Adding upstream version 6.0.4-dfsg.upstream/6.0.4-dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 4806 insertions, 0 deletions

diff --git a/src/VBox/Devices/VMMDev/VMMDev.cpp b/src/VBox/Devices/VMMDev/VMMDev.cpp
new file mode 100644
index 00000000..25dd6ddb
--- /dev/null
+++ b/src/VBox/Devices/VMMDev/VMMDev.cpp
@@ -0,0 +1,4806 @@
+/* $Id: VMMDev.cpp $ */
+/** @file
+ * VMMDev - Guest <-> VMM/Host communication device.
+ */
+
+/*
+ * Copyright (C) 2006-2019 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ */
+
+/** @page pg_vmmdev   The VMM Device.
+ *
+ * The VMM device is a custom hardware device emulation for communicating with
+ * the guest additions.
+ *
+ * Whenever host wants to inform guest about something an IRQ notification will
+ * be raised.
+ *
+ * VMMDev PDM interface will contain the guest notification method.
+ *
+ * There is a 32 bit event mask which will be read by guest on an interrupt.  A
+ * non zero bit in the mask means that the specific event occurred and requires
+ * processing on guest side.
+ *
+ * After reading the event mask guest must issue a generic request
+ * AcknowlegdeEvents.
+ *
+ * IRQ line is set to 1 (request) if there are unprocessed events, that is the
+ * event mask is not zero.
+ *
+ * After receiving an interrupt and checking event mask, the guest must process
+ * events using the event specific mechanism.
+ *
+ * That is if mouse capabilities were changed, guest will use
+ * VMMDev_GetMouseStatus generic request.
+ *
+ * Event mask is only a set of flags indicating that guest must proceed with a
+ * procedure.
+ *
+ * Unsupported events are therefore ignored. The guest additions must inform
+ * host which events they want to receive, to avoid unnecessary IRQ processing.
+ * By default no events are signalled to guest.
+ *
+ * This seems to be fast method. It requires only one context switch for an
+ * event processing.
+ *
+ *
+ * @section sec_vmmdev_heartbeat    Heartbeat
+ *
+ * The heartbeat is a feature to monitor whether the guest OS is hung or not.
+ *
+ * The main kernel component of the guest additions, VBoxGuest, sets up a timer
+ * at a frequency returned by VMMDevReq_HeartbeatConfigure
+ * (VMMDevReqHeartbeat::cNsInterval, VMMDEV::cNsHeartbeatInterval) and performs
+ * a VMMDevReq_GuestHeartbeat request every time the timer ticks.
+ *
+ * The host side (VMMDev) arms a timer with a more distant deadline
+ * (VMMDEV::cNsHeartbeatTimeout), twice cNsHeartbeatInterval by default.  Each
+ * time a VMMDevReq_GuestHeartbeat request comes in, the timer is rearmed with
+ * the same relative deadline.  So, as long as VMMDevReq_GuestHeartbeat comes
+ * when they should, the host timer will never fire.
+ *
+ * When the timer fires, we consider the guest as hung / flatlined / dead.
+ * Currently we only LogRel that, but it's easy to extend this with an event in
+ * Main API.
+ *
+ * Should the guest reawaken at some later point, we LogRel that event and
+ * continue as normal.  Again something which would merit an API event.
+ *
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+/* Enable dev_vmm Log3 statements to get IRQ-related logging. */
+#define LOG_GROUP LOG_GROUP_DEV_VMM
+#include <VBox/AssertGuest.h>
+#include <VBox/VMMDev.h>
+#include <VBox/vmm/dbgf.h>
+#include <VBox/vmm/mm.h>
+#include <VBox/log.h>
+#include <VBox/param.h>
+#include <iprt/path.h>
+#include <iprt/dir.h>
+#include <iprt/file.h>
+#include <VBox/vmm/pgm.h>
+#include <VBox/err.h>
+#include <VBox/vmm/vm.h> /* for VM_IS_EMT */
+#include <VBox/dbg.h>
+#include <VBox/version.h>
+
+#include <iprt/asm.h>
+#include <iprt/asm-amd64-x86.h>
+#include <iprt/assert.h>
+#include <iprt/buildconfig.h>
+#include <iprt/string.h>
+#include <iprt/time.h>
+#ifndef IN_RC
+# include <iprt/mem.h>
+#endif
+#ifdef IN_RING3
+# include <iprt/uuid.h>
+#endif
+
+#include "VMMDevState.h"
+#ifdef VBOX_WITH_HGCM
+# include "VMMDevHGCM.h"
+#endif
+#ifndef VBOX_WITHOUT_TESTING_FEATURES
+# include "VMMDevTesting.h"
+#endif
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+#define VMMDEV_INTERFACE_VERSION_IS_1_03(s) \
+    (   RT_HIWORD((s)->guestInfo.interfaceVersion) == 1 \
+     && RT_LOWORD((s)->guestInfo.interfaceVersion) == 3 )
+
+#define VMMDEV_INTERFACE_VERSION_IS_OK(additionsVersion) \
+      (   RT_HIWORD(additionsVersion) == RT_HIWORD(VMMDEV_VERSION) \
+       && RT_LOWORD(additionsVersion) <= RT_LOWORD(VMMDEV_VERSION) )
+
+#define VMMDEV_INTERFACE_VERSION_IS_OLD(additionsVersion) \
+      (   (RT_HIWORD(additionsVersion) < RT_HIWORD(VMMDEV_VERSION) \
+       || (   RT_HIWORD(additionsVersion) == RT_HIWORD(VMMDEV_VERSION) \
+           && RT_LOWORD(additionsVersion) <= RT_LOWORD(VMMDEV_VERSION) ) )
+
+#define VMMDEV_INTERFACE_VERSION_IS_TOO_OLD(additionsVersion) \
+      ( RT_HIWORD(additionsVersion) < RT_HIWORD(VMMDEV_VERSION) )
+
+#define VMMDEV_INTERFACE_VERSION_IS_NEW(additionsVersion) \
+      (   RT_HIWORD(additionsVersion) > RT_HIWORD(VMMDEV_VERSION) \
+       || (   RT_HIWORD(additionsVersion) == RT_HIWORD(VMMDEV_VERSION) \
+           && RT_LOWORD(additionsVersion) >  RT_LOWORD(VMMDEV_VERSION) ) )
+
+/** Default interval in nanoseconds between guest heartbeats.
+ *  Used when no HeartbeatInterval is set in CFGM and for setting
+ *  HB check timer if the guest's heartbeat frequency is less than 1Hz. */
+#define VMMDEV_HEARTBEAT_DEFAULT_INTERVAL                       (2U*RT_NS_1SEC_64)
+
+
+#ifndef VBOX_DEVICE_STRUCT_TESTCASE
+#ifdef IN_RING3
+
+/* -=-=-=-=- Misc Helpers -=-=-=-=- */
+
+/**
+ * Log information about the Guest Additions.
+ *
+ * @param   pGuestInfo  The information we've got from the Guest Additions driver.
+ */
+static void vmmdevLogGuestOsInfo(VBoxGuestInfo *pGuestInfo)
+{
+    const char *pszOs;
+    switch (pGuestInfo->osType & ~VBOXOSTYPE_x64)
+    {
+        case VBOXOSTYPE_DOS:                              pszOs = "DOS";            break;
+        case VBOXOSTYPE_Win31:                            pszOs = "Windows 3.1";    break;
+        case VBOXOSTYPE_Win9x:                            pszOs = "Windows 9x";     break;
+        case VBOXOSTYPE_Win95:                            pszOs = "Windows 95";     break;
+        case VBOXOSTYPE_Win98:                            pszOs = "Windows 98";     break;
+        case VBOXOSTYPE_WinMe:                            pszOs = "Windows Me";     break;
+        case VBOXOSTYPE_WinNT:                            pszOs = "Windows NT";     break;
+        case VBOXOSTYPE_WinNT3x:                          pszOs = "Windows NT 3.x"; break;
+        case VBOXOSTYPE_WinNT4:                           pszOs = "Windows NT4";    break;
+        case VBOXOSTYPE_Win2k:                            pszOs = "Windows 2k";     break;
+        case VBOXOSTYPE_WinXP:                            pszOs = "Windows XP";     break;
+        case VBOXOSTYPE_Win2k3:                           pszOs = "Windows 2k3";    break;
+        case VBOXOSTYPE_WinVista:                         pszOs = "Windows Vista";  break;
+        case VBOXOSTYPE_Win2k8:                           pszOs = "Windows 2k8";    break;
+        case VBOXOSTYPE_Win7:                             pszOs = "Windows 7";      break;
+        case VBOXOSTYPE_Win8:                             pszOs = "Windows 8";      break;
+        case VBOXOSTYPE_Win2k12_x64 & ~VBOXOSTYPE_x64:    pszOs = "Windows 2k12";   break;
+        case VBOXOSTYPE_Win81:                            pszOs = "Windows 8.1";    break;
+        case VBOXOSTYPE_Win10:                            pszOs = "Windows 10";     break;
+        case VBOXOSTYPE_Win2k16_x64 & ~VBOXOSTYPE_x64:    pszOs = "Windows 2k16";   break;
+        case VBOXOSTYPE_OS2:                              pszOs = "OS/2";           break;
+        case VBOXOSTYPE_OS2Warp3:                         pszOs = "OS/2 Warp 3";    break;
+        case VBOXOSTYPE_OS2Warp4:                         pszOs = "OS/2 Warp 4";    break;
+        case VBOXOSTYPE_OS2Warp45:                        pszOs = "OS/2 Warp 4.5";  break;
+        case VBOXOSTYPE_ECS:                              pszOs = "OS/2 ECS";       break;
+        case VBOXOSTYPE_OS21x:                            pszOs = "OS/2 2.1x";      break;
+        case VBOXOSTYPE_Linux:                            pszOs = "Linux";          break;
+        case VBOXOSTYPE_Linux22:                          pszOs = "Linux 2.2";      break;
+        case VBOXOSTYPE_Linux24:                          pszOs = "Linux 2.4";      break;
+        case VBOXOSTYPE_Linux26:                          pszOs = "Linux >= 2.6";   break;
+        case VBOXOSTYPE_ArchLinux:                        pszOs = "ArchLinux";      break;
+        case VBOXOSTYPE_Debian:                           pszOs = "Debian";         break;
+        case VBOXOSTYPE_OpenSUSE:                         pszOs = "openSUSE";       break;
+        case VBOXOSTYPE_FedoraCore:                       pszOs = "Fedora";         break;
+        case VBOXOSTYPE_Gentoo:                           pszOs = "Gentoo";         break;
+        case VBOXOSTYPE_Mandriva:                         pszOs = "Mandriva";       break;
+        case VBOXOSTYPE_RedHat:                           pszOs = "RedHat";         break;
+        case VBOXOSTYPE_Turbolinux:                       pszOs = "TurboLinux";     break;
+        case VBOXOSTYPE_Ubuntu:                           pszOs = "Ubuntu";         break;
+        case VBOXOSTYPE_Xandros:                          pszOs = "Xandros";        break;
+        case VBOXOSTYPE_Oracle:                           pszOs = "Oracle Linux";   break;
+        case VBOXOSTYPE_FreeBSD:                          pszOs = "FreeBSD";        break;
+        case VBOXOSTYPE_OpenBSD:                          pszOs = "OpenBSD";        break;
+        case VBOXOSTYPE_NetBSD:                           pszOs = "NetBSD";         break;
+        case VBOXOSTYPE_Netware:                          pszOs = "Netware";        break;
+        case VBOXOSTYPE_Solaris:                          pszOs = "Solaris";        break;
+        case VBOXOSTYPE_OpenSolaris:                      pszOs = "OpenSolaris";    break;
+        case VBOXOSTYPE_Solaris11_x64 & ~VBOXOSTYPE_x64:  pszOs = "Solaris 11";     break;
+        case VBOXOSTYPE_MacOS:                            pszOs = "Mac OS X";       break;
+        case VBOXOSTYPE_MacOS106:                         pszOs = "Mac OS X 10.6";  break;
+        case VBOXOSTYPE_MacOS107_x64 & ~VBOXOSTYPE_x64:   pszOs = "Mac OS X 10.7";  break;
+        case VBOXOSTYPE_MacOS108_x64 & ~VBOXOSTYPE_x64:   pszOs = "Mac OS X 10.8";  break;
+        case VBOXOSTYPE_MacOS109_x64 & ~VBOXOSTYPE_x64:   pszOs = "Mac OS X 10.9";  break;
+        case VBOXOSTYPE_MacOS1010_x64 & ~VBOXOSTYPE_x64:  pszOs = "Mac OS X 10.10"; break;
+        case VBOXOSTYPE_MacOS1011_x64 & ~VBOXOSTYPE_x64:  pszOs = "Mac OS X 10.11"; break;
+        case VBOXOSTYPE_MacOS1012_x64 & ~VBOXOSTYPE_x64:  pszOs = "macOS 10.12";    break;
+        case VBOXOSTYPE_MacOS1013_x64 & ~VBOXOSTYPE_x64:  pszOs = "macOS 10.13";    break;
+        case VBOXOSTYPE_Haiku:                            pszOs = "Haiku";          break;
+        default:                                          pszOs = "unknown";        break;
+    }
+    LogRel(("VMMDev: Guest Additions information report: Interface = 0x%08X osType = 0x%08X (%s, %u-bit)\n",
+            pGuestInfo->interfaceVersion, pGuestInfo->osType, pszOs,
+            pGuestInfo->osType & VBOXOSTYPE_x64 ? 64 : 32));
+}
+
+
+/**
+ * Sets the IRQ (raise it or lower it) for 1.03 additions.
+ *
+ * @param   pThis       The VMMDev state.
+ * @thread  Any.
+ * @remarks Must be called owning the critical section.
+ */
+static void vmmdevSetIRQ_Legacy(PVMMDEV pThis)
+{
+    if (pThis->fu32AdditionsOk)
+    {
+        /* Filter unsupported events */
+        uint32_t fEvents = pThis->u32HostEventFlags & pThis->CTX_SUFF(pVMMDevRAM)->V.V1_03.u32GuestEventMask;
+
+        Log(("vmmdevSetIRQ: fEvents=%#010x, u32HostEventFlags=%#010x, u32GuestEventMask=%#010x.\n",
+             fEvents, pThis->u32HostEventFlags, pThis->CTX_SUFF(pVMMDevRAM)->V.V1_03.u32GuestEventMask));
+
+        /* Move event flags to VMMDev RAM */
+        pThis->CTX_SUFF(pVMMDevRAM)->V.V1_03.u32HostEvents = fEvents;
+
+        uint32_t uIRQLevel = 0;
+        if (fEvents)
+        {
+            /* Clear host flags which will be delivered to guest. */
+            pThis->u32HostEventFlags &= ~fEvents;
+            Log(("vmmdevSetIRQ: u32HostEventFlags=%#010x\n", pThis->u32HostEventFlags));
+            uIRQLevel = 1;
+        }
+
+        /* Set IRQ level for pin 0 (see NoWait comment in vmmdevMaybeSetIRQ). */
+        /** @todo make IRQ pin configurable, at least a symbolic constant */
+        PDMDevHlpPCISetIrqNoWait(pThis->CTX_SUFF(pDevIns), 0, uIRQLevel);
+        Log(("vmmdevSetIRQ: IRQ set %d\n", uIRQLevel));
+    }
+    else
+        Log(("vmmdevSetIRQ: IRQ is not generated, guest has not yet reported to us.\n"));
+}
+
+
+/**
+ * Sets the IRQ if there are events to be delivered.
+ *
+ * @param   pThis       The VMMDev state.
+ * @thread  Any.
+ * @remarks Must be called owning the critical section.
+ */
+static void vmmdevMaybeSetIRQ(PVMMDEV pThis)
+{
+    Log3(("vmmdevMaybeSetIRQ: u32HostEventFlags=%#010x, u32GuestFilterMask=%#010x.\n",
+          pThis->u32HostEventFlags, pThis->u32GuestFilterMask));
+
+    if (pThis->u32HostEventFlags & pThis->u32GuestFilterMask)
+    {
+        /*
+         * Note! No need to wait for the IRQs to be set (if we're not luck
+         *       with the locks, etc).  It is a notification about something,
+         *       which has already happened.
+         */
+        pThis->pVMMDevRAMR3->V.V1_04.fHaveEvents = true;
+        PDMDevHlpPCISetIrqNoWait(pThis->pDevInsR3, 0, 1);
+        Log3(("vmmdevMaybeSetIRQ: IRQ set.\n"));
+    }
+}
+
+/**
+ * Notifies the guest about new events (@a fAddEvents).
+ *
+ * @param   pThis           The VMMDev state.
+ * @param   fAddEvents      New events to add.
+ * @thread  Any.
+ * @remarks Must be called owning the critical section.
+ */
+static void vmmdevNotifyGuestWorker(PVMMDEV pThis, uint32_t fAddEvents)
+{
+    Log3(("vmmdevNotifyGuestWorker: fAddEvents=%#010x.\n", fAddEvents));
+    Assert(PDMCritSectIsOwner(&pThis->CritSect));
+
+    if (!VMMDEV_INTERFACE_VERSION_IS_1_03(pThis))
+    {
+        Log3(("vmmdevNotifyGuestWorker: New additions detected.\n"));
+
+        if (pThis->fu32AdditionsOk)
+        {
+            const bool fHadEvents = (pThis->u32HostEventFlags & pThis->u32GuestFilterMask) != 0;
+
+            Log3(("vmmdevNotifyGuestWorker: fHadEvents=%d, u32HostEventFlags=%#010x, u32GuestFilterMask=%#010x.\n",
+                  fHadEvents, pThis->u32HostEventFlags, pThis->u32GuestFilterMask));
+
+            pThis->u32HostEventFlags |= fAddEvents;
+
+            if (!fHadEvents)
+                vmmdevMaybeSetIRQ(pThis);
+        }
+        else
+        {
+            pThis->u32HostEventFlags |= fAddEvents;
+            Log(("vmmdevNotifyGuestWorker: IRQ is not generated, guest has not yet reported to us.\n"));
+        }
+    }
+    else
+    {
+        Log3(("vmmdevNotifyGuestWorker: Old additions detected.\n"));
+
+        pThis->u32HostEventFlags |= fAddEvents;
+        vmmdevSetIRQ_Legacy(pThis);
+    }
+}
+
+
+
+/* -=-=-=-=- Interfaces shared with VMMDevHGCM.cpp  -=-=-=-=- */
+
+/**
+ * Notifies the guest about new events (@a fAddEvents).
+ *
+ * This is used by VMMDev.cpp as well as VMMDevHGCM.cpp.
+ *
+ * @param   pThis           The VMMDev state.
+ * @param   fAddEvents      New events to add.
+ * @thread  Any.
+ */
+void VMMDevNotifyGuest(PVMMDEV pThis, uint32_t fAddEvents)
+{
+    Log3(("VMMDevNotifyGuest: fAddEvents=%#010x\n", fAddEvents));
+
+    /*
+     * Only notify the VM when it's running.
+     */
+    VMSTATE enmVMState = PDMDevHlpVMState(pThis->pDevInsR3);
+    if (   enmVMState == VMSTATE_RUNNING
+        || enmVMState == VMSTATE_RUNNING_LS
+        || enmVMState == VMSTATE_LOADING
+        || enmVMState == VMSTATE_RESUMING
+        || enmVMState == VMSTATE_SUSPENDING
+        || enmVMState == VMSTATE_SUSPENDING_LS
+        || enmVMState == VMSTATE_SUSPENDING_EXT_LS
+        || enmVMState == VMSTATE_DEBUGGING
+        || enmVMState == VMSTATE_DEBUGGING_LS
+       )
+    {
+        PDMCritSectEnter(&pThis->CritSect, VERR_IGNORED);
+        vmmdevNotifyGuestWorker(pThis, fAddEvents);
+        PDMCritSectLeave(&pThis->CritSect);
+    }
+    else
+        LogRel(("VMMDevNotifyGuest: fAddEvents=%#x ignored because enmVMState=%d\n", fAddEvents, enmVMState));
+}
+
+/**
+ * Code shared by VMMDevReq_CtlGuestFilterMask and HGCM for controlling the
+ * events the guest are interested in.
+ *
+ * @param   pThis           The VMMDev state.
+ * @param   fOrMask         Events to add (VMMDEV_EVENT_XXX). Pass 0 for no
+ *                          change.
+ * @param   fNotMask        Events to remove (VMMDEV_EVENT_XXX). Pass 0 for no
+ *                          change.
+ *
+ * @remarks When HGCM will automatically enable VMMDEV_EVENT_HGCM when the guest
+ *          starts submitting HGCM requests.  Otherwise, the events are
+ *          controlled by the guest.
+ */
+void VMMDevCtlSetGuestFilterMask(PVMMDEV pThis, uint32_t fOrMask, uint32_t fNotMask)
+{
+    PDMCritSectEnter(&pThis->CritSect, VERR_IGNORED);
+
+    const bool fHadEvents = (pThis->u32HostEventFlags & pThis->u32GuestFilterMask) != 0;
+
+    Log(("VMMDevCtlSetGuestFilterMask: fOrMask=%#010x, u32NotMask=%#010x, fHadEvents=%d.\n", fOrMask, fNotMask, fHadEvents));
+    if (fHadEvents)
+    {
+        if (!pThis->fNewGuestFilterMask)
+            pThis->u32NewGuestFilterMask = pThis->u32GuestFilterMask;
+
+        pThis->u32NewGuestFilterMask |= fOrMask;
+        pThis->u32NewGuestFilterMask &= ~fNotMask;
+        pThis->fNewGuestFilterMask = true;
+    }
+    else
+    {
+        pThis->u32GuestFilterMask |= fOrMask;
+        pThis->u32GuestFilterMask &= ~fNotMask;
+        vmmdevMaybeSetIRQ(pThis);
+    }
+
+    PDMCritSectLeave(&pThis->CritSect);
+}
+
+
+
+/* -=-=-=-=- Request processing functions. -=-=-=-=- */
+
+/**
+ * Handles VMMDevReq_ReportGuestInfo.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pRequestHeader  The header of the request to handle.
+ */
+static int vmmdevReqHandler_ReportGuestInfo(PVMMDEV pThis, VMMDevRequestHeader *pRequestHeader)
+{
+    AssertMsgReturn(pRequestHeader->size == sizeof(VMMDevReportGuestInfo), ("%u\n", pRequestHeader->size), VERR_INVALID_PARAMETER);
+    VBoxGuestInfo const *pInfo = &((VMMDevReportGuestInfo *)pRequestHeader)->guestInfo;
+
+    if (memcmp(&pThis->guestInfo, pInfo, sizeof(*pInfo)) != 0)
+    {
+        /* Make a copy of supplied information. */
+        pThis->guestInfo = *pInfo;
+
+        /* Check additions interface version. */
+        pThis->fu32AdditionsOk = VMMDEV_INTERFACE_VERSION_IS_OK(pThis->guestInfo.interfaceVersion);
+
+        vmmdevLogGuestOsInfo(&pThis->guestInfo);
+
+        if (pThis->pDrv && pThis->pDrv->pfnUpdateGuestInfo)
+            pThis->pDrv->pfnUpdateGuestInfo(pThis->pDrv, &pThis->guestInfo);
+    }
+
+    if (!pThis->fu32AdditionsOk)
+        return VERR_VERSION_MISMATCH;
+
+    /* Clear our IRQ in case it was high for whatever reason. */
+    PDMDevHlpPCISetIrqNoWait(pThis->pDevInsR3, 0, 0);
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_GuestHeartbeat.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis    The VMMDev instance data.
+ */
+static int vmmDevReqHandler_GuestHeartbeat(PVMMDEV pThis)
+{
+    int rc;
+    if (pThis->fHeartbeatActive)
+    {
+        uint64_t const nsNowTS = TMTimerGetNano(pThis->pFlatlinedTimer);
+        if (!pThis->fFlatlined)
+        { /* likely */ }
+        else
+        {
+            LogRel(("VMMDev: GuestHeartBeat: Guest is alive (gone %'llu ns)\n", nsNowTS - pThis->nsLastHeartbeatTS));
+            ASMAtomicWriteBool(&pThis->fFlatlined, false);
+        }
+        ASMAtomicWriteU64(&pThis->nsLastHeartbeatTS, nsNowTS);
+
+        /* Postpone (or restart if we missed a beat) the timeout timer. */
+        rc = TMTimerSetNano(pThis->pFlatlinedTimer, pThis->cNsHeartbeatTimeout);
+    }
+    else
+        rc = VINF_SUCCESS;
+    return rc;
+}
+
+
+/**
+ * Timer that fires when where have been no heartbeats for a given time.
+ *
+ * @remarks Does not take the VMMDev critsect.
+ */
+static DECLCALLBACK(void) vmmDevHeartbeatFlatlinedTimer(PPDMDEVINS pDevIns, PTMTIMER pTimer, void *pvUser)
+{
+    RT_NOREF1(pDevIns);
+    PVMMDEV pThis = (PVMMDEV)pvUser;
+    if (pThis->fHeartbeatActive)
+    {
+        uint64_t cNsElapsed = TMTimerGetNano(pTimer) - pThis->nsLastHeartbeatTS;
+        if (   !pThis->fFlatlined
+            && cNsElapsed >= pThis->cNsHeartbeatInterval)
+        {
+            LogRel(("VMMDev: vmmDevHeartbeatFlatlinedTimer: Guest seems to be unresponsive. Last heartbeat received %RU64 seconds ago\n",
+                    cNsElapsed / RT_NS_1SEC));
+            ASMAtomicWriteBool(&pThis->fFlatlined, true);
+        }
+    }
+}
+
+
+/**
+ * Handles VMMDevReq_HeartbeatConfigure.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis     The VMMDev instance data.
+ * @param   pReqHdr   The header of the request to handle.
+ */
+static int vmmDevReqHandler_HeartbeatConfigure(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    AssertMsgReturn(pReqHdr->size == sizeof(VMMDevReqHeartbeat), ("%u\n", pReqHdr->size), VERR_INVALID_PARAMETER);
+    VMMDevReqHeartbeat *pReq = (VMMDevReqHeartbeat *)pReqHdr;
+    int rc;
+
+    pReq->cNsInterval = pThis->cNsHeartbeatInterval;
+
+    if (pReq->fEnabled != pThis->fHeartbeatActive)
+    {
+        ASMAtomicWriteBool(&pThis->fHeartbeatActive, pReq->fEnabled);
+        if (pReq->fEnabled)
+        {
+            /*
+             * Activate the heartbeat monitor.
+             */
+            pThis->nsLastHeartbeatTS = TMTimerGetNano(pThis->pFlatlinedTimer);
+            rc = TMTimerSetNano(pThis->pFlatlinedTimer, pThis->cNsHeartbeatTimeout);
+            if (RT_SUCCESS(rc))
+                LogRel(("VMMDev: Heartbeat flatline timer set to trigger after %'RU64 ns\n", pThis->cNsHeartbeatTimeout));
+            else
+                LogRel(("VMMDev: Error starting flatline timer (heartbeat): %Rrc\n", rc));
+        }
+        else
+        {
+            /*
+             * Deactivate the heartbeat monitor.
+             */
+            rc = TMTimerStop(pThis->pFlatlinedTimer);
+            LogRel(("VMMDev: Heartbeat checking timer has been stopped (rc=%Rrc)\n", rc));
+        }
+    }
+    else
+    {
+        LogRel(("VMMDev: vmmDevReqHandler_HeartbeatConfigure: No change (fHeartbeatActive=%RTbool)\n", pThis->fHeartbeatActive));
+        rc = VINF_SUCCESS;
+    }
+
+    return rc;
+}
+
+
+/**
+ * Handles VMMDevReq_NtBugCheck.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis     The VMMDev instance data.
+ * @param   pReqHdr   The header of the request to handle.
+ */
+static int vmmDevReqHandler_NtBugCheck(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    if (pReqHdr->size == sizeof(VMMDevReqNtBugCheck))
+    {
+        VMMDevReqNtBugCheck const *pReq = (VMMDevReqNtBugCheck const *)pReqHdr;
+        DBGFR3ReportBugCheck(PDMDevHlpGetVM(pThis->pDevInsR3), PDMDevHlpGetVMCPU(pThis->pDevInsR3), DBGFEVENT_BSOD_VMMDEV,
+                             pReq->uBugCheck, pReq->auParameters[0], pReq->auParameters[1],
+                             pReq->auParameters[2], pReq->auParameters[3]);
+    }
+    else if (pReqHdr->size == sizeof(VMMDevRequestHeader))
+    {
+        LogRel(("VMMDev: NT BugCheck w/o data.\n"));
+        DBGFR3ReportBugCheck(PDMDevHlpGetVM(pThis->pDevInsR3), PDMDevHlpGetVMCPU(pThis->pDevInsR3), DBGFEVENT_BSOD_VMMDEV,
+                             0, 0, 0, 0, 0);
+    }
+    else
+        return VERR_INVALID_PARAMETER;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Validates a publisher tag.
+ *
+ * @returns true / false.
+ * @param   pszTag              Tag to validate.
+ */
+static bool vmmdevReqIsValidPublisherTag(const char *pszTag)
+{
+    /* Note! This character set is also found in Config.kmk. */
+    static char const s_szValidChars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz()[]{}+-.,";
+
+    while (*pszTag != '\0')
+    {
+        if (!strchr(s_szValidChars, *pszTag))
+            return false;
+        pszTag++;
+    }
+    return true;
+}
+
+
+/**
+ * Validates a build tag.
+ *
+ * @returns true / false.
+ * @param   pszTag              Tag to validate.
+ */
+static bool vmmdevReqIsValidBuildTag(const char *pszTag)
+{
+    int cchPrefix;
+    if (!strncmp(pszTag, "RC", 2))
+        cchPrefix = 2;
+    else if (!strncmp(pszTag, "BETA", 4))
+        cchPrefix = 4;
+    else if (!strncmp(pszTag, "ALPHA", 5))
+        cchPrefix = 5;
+    else
+        return false;
+
+    if (pszTag[cchPrefix] == '\0')
+        return true;
+
+    uint8_t u8;
+    int rc = RTStrToUInt8Full(&pszTag[cchPrefix], 10, &u8);
+    return rc == VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_ReportGuestInfo2.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_ReportGuestInfo2(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    AssertMsgReturn(pReqHdr->size == sizeof(VMMDevReportGuestInfo2), ("%u\n", pReqHdr->size), VERR_INVALID_PARAMETER);
+    VBoxGuestInfo2 const *pInfo2 = &((VMMDevReportGuestInfo2 *)pReqHdr)->guestInfo;
+
+    LogRel(("VMMDev: Guest Additions information report: Version %d.%d.%d r%d '%.*s'\n",
+            pInfo2->additionsMajor, pInfo2->additionsMinor, pInfo2->additionsBuild,
+            pInfo2->additionsRevision, sizeof(pInfo2->szName), pInfo2->szName));
+
+    /* The interface was introduced in 3.2 and will definitely not be
+       backported beyond 3.0 (bird). */
+    AssertMsgReturn(pInfo2->additionsMajor >= 3,
+                    ("%u.%u.%u\n", pInfo2->additionsMajor, pInfo2->additionsMinor, pInfo2->additionsBuild),
+                    VERR_INVALID_PARAMETER);
+
+    /* The version must fit in a full version compression. */
+    uint32_t uFullVersion = VBOX_FULL_VERSION_MAKE(pInfo2->additionsMajor, pInfo2->additionsMinor, pInfo2->additionsBuild);
+    AssertMsgReturn(   VBOX_FULL_VERSION_GET_MAJOR(uFullVersion) == pInfo2->additionsMajor
+                    && VBOX_FULL_VERSION_GET_MINOR(uFullVersion) == pInfo2->additionsMinor
+                    && VBOX_FULL_VERSION_GET_BUILD(uFullVersion) == pInfo2->additionsBuild,
+                    ("%u.%u.%u\n", pInfo2->additionsMajor, pInfo2->additionsMinor, pInfo2->additionsBuild),
+                    VERR_OUT_OF_RANGE);
+
+    /*
+     * Validate the name.
+     * Be less strict towards older additions (< v4.1.50).
+     */
+    AssertCompile(sizeof(pThis->guestInfo2.szName) == sizeof(pInfo2->szName));
+    AssertReturn(RTStrEnd(pInfo2->szName, sizeof(pInfo2->szName)) != NULL, VERR_INVALID_PARAMETER);
+    const char *pszName = pInfo2->szName;
+
+    /* The version number which shouldn't be there. */
+    char        szTmp[sizeof(pInfo2->szName)];
+    size_t      cchStart = RTStrPrintf(szTmp, sizeof(szTmp), "%u.%u.%u", pInfo2->additionsMajor, pInfo2->additionsMinor, pInfo2->additionsBuild);
+    AssertMsgReturn(!strncmp(pszName, szTmp, cchStart), ("%s != %s\n", pszName, szTmp), VERR_INVALID_PARAMETER);
+    pszName += cchStart;
+
+    /* Now we can either have nothing or a build tag or/and a publisher tag. */
+    if (*pszName != '\0')
+    {
+        const char *pszRelaxedName = "";
+        bool const fStrict = pInfo2->additionsMajor > 4
+                          || (pInfo2->additionsMajor == 4 && pInfo2->additionsMinor > 1)
+                          || (pInfo2->additionsMajor == 4 && pInfo2->additionsMinor == 1 && pInfo2->additionsBuild >= 50);
+        bool fOk = false;
+        if (*pszName == '_')
+        {
+            pszName++;
+            strcpy(szTmp, pszName);
+            char *pszTag2 = strchr(szTmp, '_');
+            if (!pszTag2)
+            {
+                fOk = vmmdevReqIsValidBuildTag(szTmp)
+                   || vmmdevReqIsValidPublisherTag(szTmp);
+            }
+            else
+            {
+                *pszTag2++ = '\0';
+                fOk = vmmdevReqIsValidBuildTag(szTmp);
+                if (fOk)
+                {
+                    fOk = vmmdevReqIsValidPublisherTag(pszTag2);
+                    if (!fOk)
+                        pszRelaxedName = szTmp;
+                }
+            }
+        }
+
+        if (!fOk)
+        {
+            AssertLogRelMsgReturn(!fStrict, ("%s", pszName), VERR_INVALID_PARAMETER);
+
+            /* non-strict mode, just zap the extra stuff. */
+            LogRel(("VMMDev: ReportGuestInfo2: Ignoring unparsable version name bits: '%s' -> '%s'.\n", pszName, pszRelaxedName));
+            pszName = pszRelaxedName;
+        }
+    }
+
+    /*
+     * Save the info and tell Main or whoever is listening.
+     */
+    pThis->guestInfo2.uFullVersion  = uFullVersion;
+    pThis->guestInfo2.uRevision     = pInfo2->additionsRevision;
+    pThis->guestInfo2.fFeatures     = pInfo2->additionsFeatures;
+    strcpy(pThis->guestInfo2.szName, pszName);
+
+    if (pThis->pDrv && pThis->pDrv->pfnUpdateGuestInfo2)
+        pThis->pDrv->pfnUpdateGuestInfo2(pThis->pDrv, uFullVersion, pszName, pInfo2->additionsRevision, pInfo2->additionsFeatures);
+
+    /* Clear our IRQ in case it was high for whatever reason. */
+    PDMDevHlpPCISetIrqNoWait(pThis->pDevInsR3, 0, 0);
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Allocates a new facility status entry, initializing it to inactive.
+ *
+ * @returns Pointer to a facility status entry on success, NULL on failure
+ *          (table full).
+ * @param   pThis           The VMMDev instance data.
+ * @param   enmFacility     The facility type code.
+ * @param   fFixed          This is set when allocating the standard entries
+ *                          from the constructor.
+ * @param   pTimeSpecNow    Optionally giving the entry timestamp to use (ctor).
+ */
+static PVMMDEVFACILITYSTATUSENTRY
+vmmdevAllocFacilityStatusEntry(PVMMDEV pThis, VBoxGuestFacilityType enmFacility, bool fFixed, PCRTTIMESPEC pTimeSpecNow)
+{
+    /* If full, expunge one inactive entry. */
+    if (pThis->cFacilityStatuses == RT_ELEMENTS(pThis->aFacilityStatuses))
+    {
+        uint32_t i = pThis->cFacilityStatuses;
+        while (i-- > 0)
+        {
+            if (   pThis->aFacilityStatuses[i].enmStatus == VBoxGuestFacilityStatus_Inactive
+                && !pThis->aFacilityStatuses[i].fFixed)
+            {
+                pThis->cFacilityStatuses--;
+                int cToMove = pThis->cFacilityStatuses - i;
+                if (cToMove)
+                    memmove(&pThis->aFacilityStatuses[i], &pThis->aFacilityStatuses[i + 1],
+                            cToMove * sizeof(pThis->aFacilityStatuses[i]));
+                RT_ZERO(pThis->aFacilityStatuses[pThis->cFacilityStatuses]);
+                break;
+            }
+        }
+
+        if (pThis->cFacilityStatuses == RT_ELEMENTS(pThis->aFacilityStatuses))
+            return NULL;
+    }
+
+    /* Find location in array (it's sorted). */
+    uint32_t i = pThis->cFacilityStatuses;
+    while (i-- > 0)
+        if ((uint32_t)pThis->aFacilityStatuses[i].enmFacility < (uint32_t)enmFacility)
+            break;
+    i++;
+
+    /* Move. */
+    int cToMove = pThis->cFacilityStatuses - i;
+    if (cToMove > 0)
+        memmove(&pThis->aFacilityStatuses[i + 1], &pThis->aFacilityStatuses[i],
+                cToMove * sizeof(pThis->aFacilityStatuses[i]));
+    pThis->cFacilityStatuses++;
+
+    /* Initialize. */
+    pThis->aFacilityStatuses[i].enmFacility  = enmFacility;
+    pThis->aFacilityStatuses[i].enmStatus    = VBoxGuestFacilityStatus_Inactive;
+    pThis->aFacilityStatuses[i].fFixed       = fFixed;
+    pThis->aFacilityStatuses[i].afPadding[0] = 0;
+    pThis->aFacilityStatuses[i].afPadding[1] = 0;
+    pThis->aFacilityStatuses[i].afPadding[2] = 0;
+    pThis->aFacilityStatuses[i].fFlags       = 0;
+    if (pTimeSpecNow)
+        pThis->aFacilityStatuses[i].TimeSpecTS = *pTimeSpecNow;
+    else
+        RTTimeSpecSetNano(&pThis->aFacilityStatuses[i].TimeSpecTS, 0);
+
+    return &pThis->aFacilityStatuses[i];
+}
+
+
+/**
+ * Gets a facility status entry, allocating a new one if not already present.
+ *
+ * @returns Pointer to a facility status entry on success, NULL on failure
+ *          (table full).
+ * @param   pThis           The VMMDev instance data.
+ * @param   enmFacility     The facility type code.
+ */
+static PVMMDEVFACILITYSTATUSENTRY vmmdevGetFacilityStatusEntry(PVMMDEV pThis, VBoxGuestFacilityType enmFacility)
+{
+    /** @todo change to binary search. */
+    uint32_t i = pThis->cFacilityStatuses;
+    while (i-- > 0)
+    {
+        if (pThis->aFacilityStatuses[i].enmFacility == enmFacility)
+            return &pThis->aFacilityStatuses[i];
+        if ((uint32_t)pThis->aFacilityStatuses[i].enmFacility < (uint32_t)enmFacility)
+            break;
+    }
+    return vmmdevAllocFacilityStatusEntry(pThis, enmFacility, false /*fFixed*/, NULL);
+}
+
+
+/**
+ * Handles VMMDevReq_ReportGuestStatus.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_ReportGuestStatus(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    /*
+     * Validate input.
+     */
+    AssertMsgReturn(pReqHdr->size == sizeof(VMMDevReportGuestStatus), ("%u\n", pReqHdr->size), VERR_INVALID_PARAMETER);
+    VBoxGuestStatus *pStatus = &((VMMDevReportGuestStatus *)pReqHdr)->guestStatus;
+    AssertMsgReturn(   pStatus->facility > VBoxGuestFacilityType_Unknown
+                    && pStatus->facility <= VBoxGuestFacilityType_All,
+                    ("%d\n", pStatus->facility),
+                    VERR_INVALID_PARAMETER);
+    AssertMsgReturn(pStatus->status == (VBoxGuestFacilityStatus)(uint16_t)pStatus->status,
+                    ("%#x (%u)\n", pStatus->status, pStatus->status),
+                    VERR_OUT_OF_RANGE);
+
+    /*
+     * Do the update.
+     */
+    RTTIMESPEC Now;
+    RTTimeNow(&Now);
+    if (pStatus->facility == VBoxGuestFacilityType_All)
+    {
+        uint32_t i = pThis->cFacilityStatuses;
+        while (i-- > 0)
+        {
+            pThis->aFacilityStatuses[i].TimeSpecTS = Now;
+            pThis->aFacilityStatuses[i].enmStatus  = pStatus->status;
+            pThis->aFacilityStatuses[i].fFlags     = pStatus->flags;
+        }
+    }
+    else
+    {
+        PVMMDEVFACILITYSTATUSENTRY pEntry = vmmdevGetFacilityStatusEntry(pThis, pStatus->facility);
+        if (!pEntry)
+        {
+            LogRelMax(10, ("VMMDev: Facility table is full - facility=%u status=%u\n", pStatus->facility, pStatus->status));
+            return VERR_OUT_OF_RESOURCES;
+        }
+
+        pEntry->TimeSpecTS = Now;
+        pEntry->enmStatus  = pStatus->status;
+        pEntry->fFlags     = pStatus->flags;
+    }
+
+    if (pThis->pDrv && pThis->pDrv->pfnUpdateGuestStatus)
+        pThis->pDrv->pfnUpdateGuestStatus(pThis->pDrv, pStatus->facility, pStatus->status, pStatus->flags, &Now);
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_ReportGuestUserState.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_ReportGuestUserState(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    /*
+     * Validate input.
+     */
+    VMMDevReportGuestUserState *pReq = (VMMDevReportGuestUserState *)pReqHdr;
+    AssertMsgReturn(pReq->header.size >= sizeof(*pReq), ("%u\n", pReqHdr->size), VERR_INVALID_PARAMETER);
+
+    if (   pThis->pDrv
+        && pThis->pDrv->pfnUpdateGuestUserState)
+    {
+        /* Play safe. */
+        AssertReturn(pReq->header.size      <= _2K, VERR_TOO_MUCH_DATA);
+        AssertReturn(pReq->status.cbUser    <= 256, VERR_TOO_MUCH_DATA);
+        AssertReturn(pReq->status.cbDomain  <= 256, VERR_TOO_MUCH_DATA);
+        AssertReturn(pReq->status.cbDetails <= _1K, VERR_TOO_MUCH_DATA);
+
+        /* pbDynamic marks the beginning of the struct's dynamically
+         * allocated data area. */
+        uint8_t *pbDynamic = (uint8_t *)&pReq->status.szUser;
+        uint32_t cbLeft    = pReqHdr->size - RT_UOFFSETOF(VMMDevReportGuestUserState, status.szUser);
+
+        /* The user. */
+        AssertReturn(pReq->status.cbUser > 0, VERR_INVALID_PARAMETER); /* User name is required. */
+        AssertReturn(pReq->status.cbUser <= cbLeft, VERR_INVALID_PARAMETER);
+        const char *pszUser = (const char *)pbDynamic;
+        AssertReturn(RTStrEnd(pszUser, pReq->status.cbUser), VERR_INVALID_PARAMETER);
+        int rc = RTStrValidateEncoding(pszUser);
+        AssertRCReturn(rc, rc);
+
+        /* Advance to the next field. */
+        pbDynamic += pReq->status.cbUser;
+        cbLeft    -= pReq->status.cbUser;
+
+        /* pszDomain can be NULL. */
+        AssertReturn(pReq->status.cbDomain <= cbLeft, VERR_INVALID_PARAMETER);
+        const char *pszDomain = NULL;
+        if (pReq->status.cbDomain)
+        {
+            pszDomain = (const char *)pbDynamic;
+            AssertReturn(RTStrEnd(pszDomain, pReq->status.cbDomain), VERR_INVALID_PARAMETER);
+            rc = RTStrValidateEncoding(pszDomain);
+            AssertRCReturn(rc, rc);
+
+            /* Advance to the next field. */
+            pbDynamic += pReq->status.cbDomain;
+            cbLeft    -= pReq->status.cbDomain;
+        }
+
+        /* pbDetails can be NULL. */
+        const uint8_t *pbDetails = NULL;
+        AssertReturn(pReq->status.cbDetails <= cbLeft, VERR_INVALID_PARAMETER);
+        if (pReq->status.cbDetails > 0)
+            pbDetails = pbDynamic;
+
+        pThis->pDrv->pfnUpdateGuestUserState(pThis->pDrv, pszUser, pszDomain, (uint32_t)pReq->status.state,
+                                             pbDetails, pReq->status.cbDetails);
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_ReportGuestCapabilities.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_ReportGuestCapabilities(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevReqGuestCapabilities *pReq = (VMMDevReqGuestCapabilities *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    /* Enable VMMDEV_GUEST_SUPPORTS_GRAPHICS automatically for guests using the old
+     * request to report their capabilities.
+     */
+    const uint32_t fu32Caps = pReq->caps | VMMDEV_GUEST_SUPPORTS_GRAPHICS;
+
+    if (pThis->guestCaps != fu32Caps)
+    {
+        /* make a copy of supplied information */
+        pThis->guestCaps = fu32Caps;
+
+        LogRel(("VMMDev: Guest Additions capability report (legacy): (0x%x) seamless: %s, hostWindowMapping: %s, graphics: yes\n",
+                fu32Caps,
+                fu32Caps & VMMDEV_GUEST_SUPPORTS_SEAMLESS ? "yes" : "no",
+                fu32Caps & VMMDEV_GUEST_SUPPORTS_GUEST_HOST_WINDOW_MAPPING ? "yes" : "no"));
+
+        if (pThis->pDrv && pThis->pDrv->pfnUpdateGuestCapabilities)
+            pThis->pDrv->pfnUpdateGuestCapabilities(pThis->pDrv, fu32Caps);
+    }
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_SetGuestCapabilities.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_SetGuestCapabilities(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevReqGuestCapabilities2 *pReq = (VMMDevReqGuestCapabilities2 *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    uint32_t fu32Caps = pThis->guestCaps;
+    fu32Caps |= pReq->u32OrMask;
+    fu32Caps &= ~pReq->u32NotMask;
+
+    LogRel(("VMMDev: Guest Additions capability report: (%#x -> %#x) seamless: %s, hostWindowMapping: %s, graphics: %s\n",
+            pThis->guestCaps, fu32Caps,
+            fu32Caps & VMMDEV_GUEST_SUPPORTS_SEAMLESS ? "yes" : "no",
+            fu32Caps & VMMDEV_GUEST_SUPPORTS_GUEST_HOST_WINDOW_MAPPING ? "yes" : "no",
+            fu32Caps & VMMDEV_GUEST_SUPPORTS_GRAPHICS ? "yes" : "no"));
+
+    pThis->guestCaps = fu32Caps;
+
+    if (pThis->pDrv && pThis->pDrv->pfnUpdateGuestCapabilities)
+        pThis->pDrv->pfnUpdateGuestCapabilities(pThis->pDrv, fu32Caps);
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_GetMouseStatus.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_GetMouseStatus(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevReqMouseStatus *pReq = (VMMDevReqMouseStatus *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    pReq->mouseFeatures = pThis->mouseCapabilities
+                        & VMMDEV_MOUSE_MASK;
+    pReq->pointerXPos   = pThis->mouseXAbs;
+    pReq->pointerYPos   = pThis->mouseYAbs;
+    LogRel2(("VMMDev: vmmdevReqHandler_GetMouseStatus: mouseFeatures=%#x, xAbs=%d, yAbs=%d\n",
+             pReq->mouseFeatures, pReq->pointerXPos, pReq->pointerYPos));
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_SetMouseStatus.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_SetMouseStatus(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevReqMouseStatus *pReq = (VMMDevReqMouseStatus *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    LogRelFlow(("VMMDev: vmmdevReqHandler_SetMouseStatus: mouseFeatures=%#x\n", pReq->mouseFeatures));
+
+    bool fNotify = false;
+    if (   (pReq->mouseFeatures & VMMDEV_MOUSE_NOTIFY_HOST_MASK)
+        != (  pThis->mouseCapabilities
+            & VMMDEV_MOUSE_NOTIFY_HOST_MASK))
+        fNotify = true;
+
+    pThis->mouseCapabilities &= ~VMMDEV_MOUSE_GUEST_MASK;
+    pThis->mouseCapabilities |= (pReq->mouseFeatures & VMMDEV_MOUSE_GUEST_MASK);
+
+    LogRelFlow(("VMMDev: vmmdevReqHandler_SetMouseStatus: New host capabilities: %#x\n", pThis->mouseCapabilities));
+
+    /*
+     * Notify connector if something changed.
+     */
+    if (fNotify)
+    {
+        LogRelFlow(("VMMDev: vmmdevReqHandler_SetMouseStatus: Notifying connector\n"));
+        pThis->pDrv->pfnUpdateMouseCapabilities(pThis->pDrv, pThis->mouseCapabilities);
+    }
+
+    return VINF_SUCCESS;
+}
+
+static int vmmdevVerifyPointerShape(VMMDevReqMousePointer *pReq)
+{
+    /* Should be enough for most mouse pointers. */
+    if (pReq->width > 8192 || pReq->height > 8192)
+        return VERR_INVALID_PARAMETER;
+
+    uint32_t cbShape = (pReq->width + 7) / 8 * pReq->height; /* size of the AND mask */
+    cbShape = ((cbShape + 3) & ~3) + pReq->width * 4 * pReq->height; /* + gap + size of the XOR mask */
+    if (RT_UOFFSETOF(VMMDevReqMousePointer, pointerData) + cbShape > pReq->header.size)
+        return VERR_INVALID_PARAMETER;
+
+    return VINF_SUCCESS;
+}
+
+/**
+ * Handles VMMDevReq_SetPointerShape.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_SetPointerShape(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevReqMousePointer *pReq = (VMMDevReqMousePointer *)pReqHdr;
+    if (pReq->header.size < sizeof(*pReq))
+    {
+        AssertMsg(pReq->header.size == 0x10028 && pReq->header.version == 10000,  /* don't complain about legacy!!! */
+                  ("VMMDev mouse shape structure has invalid size %d (%#x) version=%d!\n",
+                   pReq->header.size, pReq->header.size, pReq->header.version));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    bool fVisible = RT_BOOL(pReq->fFlags & VBOX_MOUSE_POINTER_VISIBLE);
+    bool fAlpha   = RT_BOOL(pReq->fFlags & VBOX_MOUSE_POINTER_ALPHA);
+    bool fShape   = RT_BOOL(pReq->fFlags & VBOX_MOUSE_POINTER_SHAPE);
+
+    Log(("VMMDevReq_SetPointerShape: visible: %d, alpha: %d, shape = %d, width: %d, height: %d\n",
+         fVisible, fAlpha, fShape, pReq->width, pReq->height));
+
+    if (pReq->header.size == sizeof(VMMDevReqMousePointer))
+    {
+        /* The guest did not provide the shape actually. */
+        fShape = false;
+    }
+
+    /* forward call to driver */
+    if (fShape)
+    {
+        int rc = vmmdevVerifyPointerShape(pReq);
+        if (RT_FAILURE(rc))
+            return rc;
+
+        pThis->pDrv->pfnUpdatePointerShape(pThis->pDrv,
+                                           fVisible,
+                                           fAlpha,
+                                           pReq->xHot, pReq->yHot,
+                                           pReq->width, pReq->height,
+                                           pReq->pointerData);
+    }
+    else
+    {
+        pThis->pDrv->pfnUpdatePointerShape(pThis->pDrv,
+                                           fVisible,
+                                           0,
+                                           0, 0,
+                                           0, 0,
+                                           NULL);
+    }
+
+    pThis->fHostCursorRequested = fVisible;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_GetHostTime.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_GetHostTime(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevReqHostTime *pReq = (VMMDevReqHostTime *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    if (RT_LIKELY(!pThis->fGetHostTimeDisabled))
+    {
+        RTTIMESPEC now;
+        pReq->time = RTTimeSpecGetMilli(PDMDevHlpTMUtcNow(pThis->pDevInsR3, &now));
+        return VINF_SUCCESS;
+    }
+    return VERR_NOT_SUPPORTED;
+}
+
+
+/**
+ * Handles VMMDevReq_GetHypervisorInfo.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_GetHypervisorInfo(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevReqHypervisorInfo *pReq = (VMMDevReqHypervisorInfo *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    return PGMR3MappingsSize(PDMDevHlpGetVM(pThis->pDevInsR3), &pReq->hypervisorSize);
+}
+
+
+/**
+ * Handles VMMDevReq_SetHypervisorInfo.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_SetHypervisorInfo(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevReqHypervisorInfo *pReq = (VMMDevReqHypervisorInfo *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    int rc;
+    PVM pVM = PDMDevHlpGetVM(pThis->pDevInsR3);
+    if (pReq->hypervisorStart == 0)
+        rc = PGMR3MappingsUnfix(pVM);
+    else
+    {
+        /* only if the client has queried the size before! */
+        uint32_t cbMappings;
+        rc = PGMR3MappingsSize(pVM, &cbMappings);
+        if (RT_SUCCESS(rc) && pReq->hypervisorSize == cbMappings)
+        {
+            /* new reservation */
+            rc = PGMR3MappingsFix(pVM, pReq->hypervisorStart, pReq->hypervisorSize);
+            LogRel(("VMMDev: Guest reported fixed hypervisor window at 0%010x LB %#x (rc=%Rrc)\n",
+                    pReq->hypervisorStart, pReq->hypervisorSize, rc));
+        }
+        else if (RT_FAILURE(rc))
+            rc = VERR_TRY_AGAIN;
+    }
+    return rc;
+}
+
+
+/**
+ * Handles VMMDevReq_RegisterPatchMemory.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_RegisterPatchMemory(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevReqPatchMemory *pReq = (VMMDevReqPatchMemory *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    return VMMR3RegisterPatchMemory(PDMDevHlpGetVM(pThis->pDevInsR3), pReq->pPatchMem, pReq->cbPatchMem);
+}
+
+
+/**
+ * Handles VMMDevReq_DeregisterPatchMemory.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_DeregisterPatchMemory(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevReqPatchMemory *pReq = (VMMDevReqPatchMemory *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    return VMMR3DeregisterPatchMemory(PDMDevHlpGetVM(pThis->pDevInsR3), pReq->pPatchMem, pReq->cbPatchMem);
+}
+
+
+/**
+ * Handles VMMDevReq_SetPowerStatus.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_SetPowerStatus(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevPowerStateRequest *pReq = (VMMDevPowerStateRequest *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    switch (pReq->powerState)
+    {
+        case VMMDevPowerState_Pause:
+        {
+            LogRel(("VMMDev: Guest requests the VM to be suspended (paused)\n"));
+            return PDMDevHlpVMSuspend(pThis->pDevInsR3);
+        }
+
+        case VMMDevPowerState_PowerOff:
+        {
+            LogRel(("VMMDev: Guest requests the VM to be turned off\n"));
+            return PDMDevHlpVMPowerOff(pThis->pDevInsR3);
+        }
+
+        case VMMDevPowerState_SaveState:
+        {
+            if (true /*pThis->fAllowGuestToSaveState*/)
+            {
+                LogRel(("VMMDev: Guest requests the VM to be saved and powered off\n"));
+                return PDMDevHlpVMSuspendSaveAndPowerOff(pThis->pDevInsR3);
+            }
+            LogRel(("VMMDev: Guest requests the VM to be saved and powered off, declined\n"));
+            return VERR_ACCESS_DENIED;
+        }
+
+        default:
+            AssertMsgFailed(("VMMDev: Invalid power state request: %d\n", pReq->powerState));
+            return VERR_INVALID_PARAMETER;
+    }
+}
+
+
+/**
+ * Handles VMMDevReq_GetDisplayChangeRequest
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ * @remarks Deprecated.
+ */
+static int vmmdevReqHandler_GetDisplayChangeRequest(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevDisplayChangeRequest *pReq = (VMMDevDisplayChangeRequest *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+/**
+ * @todo It looks like a multi-monitor guest which only uses
+ *        @c VMMDevReq_GetDisplayChangeRequest (not the *2 version) will get
+ *        into a @c VMMDEV_EVENT_DISPLAY_CHANGE_REQUEST event loop if it tries
+ *        to acknowlege host requests for additional monitors.  Should the loop
+ *        which checks for those requests be removed?
+ */
+
+    DISPLAYCHANGEREQUEST *pDispRequest = &pThis->displayChangeData.aRequests[0];
+
+    if (pReq->eventAck == VMMDEV_EVENT_DISPLAY_CHANGE_REQUEST)
+    {
+        /* Current request has been read at least once. */
+        pDispRequest->fPending = false;
+
+        /* Check if there are more pending requests. */
+        for (unsigned i = 1; i < RT_ELEMENTS(pThis->displayChangeData.aRequests); i++)
+        {
+            if (pThis->displayChangeData.aRequests[i].fPending)
+            {
+                VMMDevNotifyGuest(pThis, VMMDEV_EVENT_DISPLAY_CHANGE_REQUEST);
+                break;
+            }
+        }
+
+        /* Remember which resolution the client has queried, subsequent reads
+         * will return the same values. */
+        pDispRequest->lastReadDisplayChangeRequest = pDispRequest->displayChangeRequest;
+        pThis->displayChangeData.fGuestSentChangeEventAck = true;
+    }
+
+    /* If not a response to a VMMDEV_EVENT_DISPLAY_CHANGE_REQUEST, just
+     * read the last valid video mode hint. This happens when the guest X server
+     * determines the initial mode. */
+    VMMDevDisplayDef const *pDisplayDef = pThis->displayChangeData.fGuestSentChangeEventAck ?
+                                              &pDispRequest->lastReadDisplayChangeRequest :
+                                              &pDispRequest->displayChangeRequest;
+    pReq->xres = RT_BOOL(pDisplayDef->fDisplayFlags & VMMDEV_DISPLAY_CX)  ? pDisplayDef->cx : 0;
+    pReq->yres = RT_BOOL(pDisplayDef->fDisplayFlags & VMMDEV_DISPLAY_CY)  ? pDisplayDef->cy : 0;
+    pReq->bpp  = RT_BOOL(pDisplayDef->fDisplayFlags & VMMDEV_DISPLAY_BPP) ? pDisplayDef->cBitsPerPixel : 0;
+
+    Log(("VMMDev: returning display change request xres = %d, yres = %d, bpp = %d\n", pReq->xres, pReq->yres, pReq->bpp));
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_GetDisplayChangeRequest2.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_GetDisplayChangeRequest2(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevDisplayChangeRequest2 *pReq = (VMMDevDisplayChangeRequest2 *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    DISPLAYCHANGEREQUEST *pDispRequest = NULL;
+
+    if (pReq->eventAck == VMMDEV_EVENT_DISPLAY_CHANGE_REQUEST)
+    {
+        /* Select a pending request to report. */
+        unsigned i;
+        for (i = 0; i < RT_ELEMENTS(pThis->displayChangeData.aRequests); i++)
+        {
+            if (pThis->displayChangeData.aRequests[i].fPending)
+            {
+                pDispRequest = &pThis->displayChangeData.aRequests[i];
+                /* Remember which request should be reported. */
+                pThis->displayChangeData.iCurrentMonitor = i;
+                Log3(("VMMDev: will report pending request for %u\n", i));
+                break;
+            }
+        }
+
+        /* Check if there are more pending requests. */
+        i++;
+        for (; i < RT_ELEMENTS(pThis->displayChangeData.aRequests); i++)
+        {
+            if (pThis->displayChangeData.aRequests[i].fPending)
+            {
+                VMMDevNotifyGuest(pThis, VMMDEV_EVENT_DISPLAY_CHANGE_REQUEST);
+                Log3(("VMMDev: another pending at %u\n", i));
+                break;
+            }
+        }
+
+        if (pDispRequest)
+        {
+            /* Current request has been read at least once. */
+            pDispRequest->fPending = false;
+
+            /* Remember which resolution the client has queried, subsequent reads
+             * will return the same values. */
+            pDispRequest->lastReadDisplayChangeRequest = pDispRequest->displayChangeRequest;
+            pThis->displayChangeData.fGuestSentChangeEventAck = true;
+        }
+        else
+        {
+             Log3(("VMMDev: no pending request!!!\n"));
+        }
+    }
+
+    if (!pDispRequest)
+    {
+        Log3(("VMMDev: default to %d\n", pThis->displayChangeData.iCurrentMonitor));
+        pDispRequest = &pThis->displayChangeData.aRequests[pThis->displayChangeData.iCurrentMonitor];
+    }
+
+    /* If not a response to a VMMDEV_EVENT_DISPLAY_CHANGE_REQUEST, just
+     * read the last valid video mode hint. This happens when the guest X server
+     * determines the initial mode. */
+    VMMDevDisplayDef const *pDisplayDef = pThis->displayChangeData.fGuestSentChangeEventAck ?
+                                              &pDispRequest->lastReadDisplayChangeRequest :
+                                              &pDispRequest->displayChangeRequest;
+    pReq->xres    = RT_BOOL(pDisplayDef->fDisplayFlags & VMMDEV_DISPLAY_CX)  ? pDisplayDef->cx : 0;
+    pReq->yres    = RT_BOOL(pDisplayDef->fDisplayFlags & VMMDEV_DISPLAY_CY)  ? pDisplayDef->cy : 0;
+    pReq->bpp     = RT_BOOL(pDisplayDef->fDisplayFlags & VMMDEV_DISPLAY_BPP) ? pDisplayDef->cBitsPerPixel : 0;
+    pReq->display = pDisplayDef->idDisplay;
+
+    Log(("VMMDev: returning display change request xres = %d, yres = %d, bpp = %d at %d\n",
+         pReq->xres, pReq->yres, pReq->bpp, pReq->display));
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_GetDisplayChangeRequestEx.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_GetDisplayChangeRequestEx(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevDisplayChangeRequestEx *pReq = (VMMDevDisplayChangeRequestEx *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    DISPLAYCHANGEREQUEST *pDispRequest = NULL;
+
+    if (pReq->eventAck == VMMDEV_EVENT_DISPLAY_CHANGE_REQUEST)
+    {
+        /* Select a pending request to report. */
+        unsigned i;
+        for (i = 0; i < RT_ELEMENTS(pThis->displayChangeData.aRequests); i++)
+        {
+            if (pThis->displayChangeData.aRequests[i].fPending)
+            {
+                pDispRequest = &pThis->displayChangeData.aRequests[i];
+                /* Remember which request should be reported. */
+                pThis->displayChangeData.iCurrentMonitor = i;
+                Log3(("VMMDev: will report pending request for %d\n",
+                      i));
+                break;
+            }
+        }
+
+        /* Check if there are more pending requests. */
+        i++;
+        for (; i < RT_ELEMENTS(pThis->displayChangeData.aRequests); i++)
+        {
+            if (pThis->displayChangeData.aRequests[i].fPending)
+            {
+                VMMDevNotifyGuest(pThis, VMMDEV_EVENT_DISPLAY_CHANGE_REQUEST);
+                Log3(("VMMDev: another pending at %d\n",
+                      i));
+                break;
+            }
+        }
+
+        if (pDispRequest)
+        {
+            /* Current request has been read at least once. */
+            pDispRequest->fPending = false;
+
+            /* Remember which resolution the client has queried, subsequent reads
+             * will return the same values. */
+            pDispRequest->lastReadDisplayChangeRequest = pDispRequest->displayChangeRequest;
+            pThis->displayChangeData.fGuestSentChangeEventAck = true;
+        }
+        else
+        {
+             Log3(("VMMDev: no pending request!!!\n"));
+        }
+    }
+
+    if (!pDispRequest)
+    {
+        Log3(("VMMDev: default to %d\n",
+              pThis->displayChangeData.iCurrentMonitor));
+        pDispRequest = &pThis->displayChangeData.aRequests[pThis->displayChangeData.iCurrentMonitor];
+    }
+
+    /* If not a response to a VMMDEV_EVENT_DISPLAY_CHANGE_REQUEST, just
+     * read the last valid video mode hint. This happens when the guest X server
+     * determines the initial mode. */
+    VMMDevDisplayDef const *pDisplayDef = pThis->displayChangeData.fGuestSentChangeEventAck ?
+                                              &pDispRequest->lastReadDisplayChangeRequest :
+                                              &pDispRequest->displayChangeRequest;
+    pReq->xres          = RT_BOOL(pDisplayDef->fDisplayFlags & VMMDEV_DISPLAY_CX)  ? pDisplayDef->cx : 0;
+    pReq->yres          = RT_BOOL(pDisplayDef->fDisplayFlags & VMMDEV_DISPLAY_CY)  ? pDisplayDef->cy : 0;
+    pReq->bpp           = RT_BOOL(pDisplayDef->fDisplayFlags & VMMDEV_DISPLAY_BPP) ? pDisplayDef->cBitsPerPixel : 0;
+    pReq->display       = pDisplayDef->idDisplay;
+    pReq->cxOrigin      = pDisplayDef->xOrigin;
+    pReq->cyOrigin      = pDisplayDef->yOrigin;
+    pReq->fEnabled      = !RT_BOOL(pDisplayDef->fDisplayFlags & VMMDEV_DISPLAY_DISABLED);
+    pReq->fChangeOrigin = RT_BOOL(pDisplayDef->fDisplayFlags & VMMDEV_DISPLAY_ORIGIN);
+
+    Log(("VMMDevEx: returning display change request xres = %d, yres = %d, bpp = %d id %d xPos = %d, yPos = %d & Enabled=%d\n",
+         pReq->xres, pReq->yres, pReq->bpp, pReq->display, pReq->cxOrigin, pReq->cyOrigin, pReq->fEnabled));
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_GetDisplayChangeRequestMulti.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_GetDisplayChangeRequestMulti(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevDisplayChangeRequestMulti *pReq = (VMMDevDisplayChangeRequestMulti *)pReqHdr;
+    unsigned i;
+
+    ASSERT_GUEST_MSG_RETURN(pReq->header.size >= sizeof(*pReq),
+                            ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+    RT_UNTRUSTED_VALIDATED_FENCE();
+
+    uint32_t const cDisplays = pReq->cDisplays;
+    ASSERT_GUEST_MSG_RETURN(cDisplays > 0 && cDisplays <= RT_ELEMENTS(pThis->displayChangeData.aRequests),
+                            ("cDisplays %u\n", cDisplays), VERR_INVALID_PARAMETER);
+    RT_UNTRUSTED_VALIDATED_FENCE();
+
+    ASSERT_GUEST_MSG_RETURN(pReq->header.size >= sizeof(*pReq) + (cDisplays - 1) * sizeof(VMMDevDisplayDef),
+                            ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+    RT_UNTRUSTED_VALIDATED_FENCE();
+
+    if (pReq->eventAck == VMMDEV_EVENT_DISPLAY_CHANGE_REQUEST)
+    {
+        uint32_t cDisplaysOut = 0;
+        /* Remember which resolution the client has queried, subsequent reads
+         * will return the same values. */
+        for (i = 0; i < RT_ELEMENTS(pThis->displayChangeData.aRequests); ++i)
+        {
+            DISPLAYCHANGEREQUEST *pDCR = &pThis->displayChangeData.aRequests[i];
+
+            pDCR->lastReadDisplayChangeRequest = pDCR->displayChangeRequest;
+
+            if (pDCR->fPending)
+            {
+                if (cDisplaysOut < cDisplays)
+                    pReq->aDisplays[cDisplaysOut] = pDCR->lastReadDisplayChangeRequest;
+
+                cDisplaysOut++;
+                pDCR->fPending = false;
+            }
+        }
+
+        pReq->cDisplays = cDisplaysOut;
+        pThis->displayChangeData.fGuestSentChangeEventAck = true;
+    }
+    else
+    {
+        /* Fill the guest request with monitor layout data. */
+        for (i = 0; i < cDisplays; ++i)
+        {
+            /* If not a response to a VMMDEV_EVENT_DISPLAY_CHANGE_REQUEST, just
+             * read the last valid video mode hint. This happens when the guest X server
+             * determines the initial mode. */
+            DISPLAYCHANGEREQUEST const *pDCR = &pThis->displayChangeData.aRequests[i];
+            VMMDevDisplayDef const *pDisplayDef = pThis->displayChangeData.fGuestSentChangeEventAck ?
+                &pDCR->lastReadDisplayChangeRequest :
+                &pDCR->displayChangeRequest;
+            pReq->aDisplays[i] = *pDisplayDef;
+        }
+    }
+
+    Log(("VMMDev: returning multimonitor display change request cDisplays %d\n", cDisplays));
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_VideoModeSupported.
+ *
+ * Query whether the given video mode is supported.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_VideoModeSupported(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevVideoModeSupportedRequest *pReq = (VMMDevVideoModeSupportedRequest *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    /* forward the call */
+    return pThis->pDrv->pfnVideoModeSupported(pThis->pDrv,
+                                              0, /* primary screen. */
+                                              pReq->width,
+                                              pReq->height,
+                                              pReq->bpp,
+                                              &pReq->fSupported);
+}
+
+
+/**
+ * Handles VMMDevReq_VideoModeSupported2.
+ *
+ * Query whether the given video mode is supported for a specific display
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_VideoModeSupported2(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevVideoModeSupportedRequest2 *pReq = (VMMDevVideoModeSupportedRequest2 *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    /* forward the call */
+    return pThis->pDrv->pfnVideoModeSupported(pThis->pDrv,
+                                              pReq->display,
+                                              pReq->width,
+                                              pReq->height,
+                                              pReq->bpp,
+                                              &pReq->fSupported);
+}
+
+
+
+/**
+ * Handles VMMDevReq_GetHeightReduction.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_GetHeightReduction(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevGetHeightReductionRequest *pReq = (VMMDevGetHeightReductionRequest *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    /* forward the call */
+    return pThis->pDrv->pfnGetHeightReduction(pThis->pDrv, &pReq->heightReduction);
+}
+
+
+/**
+ * Handles VMMDevReq_AcknowledgeEvents.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_AcknowledgeEvents(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevEvents *pReq = (VMMDevEvents *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+    STAM_REL_COUNTER_INC(&pThis->StatSlowIrqAck);
+
+    if (!VMMDEV_INTERFACE_VERSION_IS_1_03(pThis))
+    {
+        /*
+         * Note! This code is duplicated in vmmdevFastRequestIrqAck.
+         */
+        if (pThis->fNewGuestFilterMask)
+        {
+            pThis->fNewGuestFilterMask = false;
+            pThis->u32GuestFilterMask = pThis->u32NewGuestFilterMask;
+        }
+
+        pReq->events = pThis->u32HostEventFlags & pThis->u32GuestFilterMask;
+
+        pThis->u32HostEventFlags &= ~pThis->u32GuestFilterMask;
+        pThis->CTX_SUFF(pVMMDevRAM)->V.V1_04.fHaveEvents = false;
+
+        PDMDevHlpPCISetIrqNoWait(pThis->CTX_SUFF(pDevIns), 0, 0);
+    }
+    else
+        vmmdevSetIRQ_Legacy(pThis);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_CtlGuestFilterMask.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_CtlGuestFilterMask(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevCtlGuestFilterMask *pReq = (VMMDevCtlGuestFilterMask *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    LogRelFlow(("VMMDev: vmmdevReqHandler_CtlGuestFilterMask: OR mask: %#x, NOT mask: %#x\n", pReq->u32OrMask, pReq->u32NotMask));
+
+    /* HGCM event notification is enabled by the VMMDev device
+     * automatically when any HGCM command is issued.  The guest
+     * cannot disable these notifications. */
+    VMMDevCtlSetGuestFilterMask(pThis, pReq->u32OrMask, pReq->u32NotMask & ~VMMDEV_EVENT_HGCM);
+    return VINF_SUCCESS;
+}
+
+#ifdef VBOX_WITH_HGCM
+
+/**
+ * Handles VMMDevReq_HGCMConnect.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ * @param   GCPhysReqHdr    The guest physical address of the request header.
+ */
+static int vmmdevReqHandler_HGCMConnect(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr, RTGCPHYS GCPhysReqHdr)
+{
+    VMMDevHGCMConnect *pReq = (VMMDevHGCMConnect *)pReqHdr;
+    AssertMsgReturn(pReq->header.header.size >= sizeof(*pReq), ("%u\n", pReq->header.header.size), VERR_INVALID_PARAMETER); /** @todo Not sure why this is >= ... */
+
+    if (pThis->pHGCMDrv)
+    {
+        Log(("VMMDevReq_HGCMConnect\n"));
+        return vmmdevHGCMConnect(pThis, pReq, GCPhysReqHdr);
+    }
+
+    Log(("VMMDevReq_HGCMConnect: HGCM Connector is NULL!\n"));
+    return VERR_NOT_SUPPORTED;
+}
+
+
+/**
+ * Handles VMMDevReq_HGCMDisconnect.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ * @param   GCPhysReqHdr    The guest physical address of the request header.
+ */
+static int vmmdevReqHandler_HGCMDisconnect(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr, RTGCPHYS GCPhysReqHdr)
+{
+    VMMDevHGCMDisconnect *pReq = (VMMDevHGCMDisconnect *)pReqHdr;
+    AssertMsgReturn(pReq->header.header.size >= sizeof(*pReq), ("%u\n", pReq->header.header.size), VERR_INVALID_PARAMETER);  /** @todo Not sure why this >= ... */
+
+    if (pThis->pHGCMDrv)
+    {
+        Log(("VMMDevReq_VMMDevHGCMDisconnect\n"));
+        return vmmdevHGCMDisconnect(pThis, pReq, GCPhysReqHdr);
+    }
+
+    Log(("VMMDevReq_VMMDevHGCMDisconnect: HGCM Connector is NULL!\n"));
+    return VERR_NOT_SUPPORTED;
+}
+
+
+/**
+ * Handles VMMDevReq_HGCMCall.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ * @param   GCPhysReqHdr    The guest physical address of the request header.
+ * @param   tsArrival       The STAM_GET_TS() value when the request arrived.
+ * @param   ppLock          Pointer to the lock info pointer (latter can be
+ *                          NULL).  Set to NULL if HGCM takes lock ownership.
+ */
+static int vmmdevReqHandler_HGCMCall(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr, RTGCPHYS GCPhysReqHdr,
+                                     uint64_t tsArrival, PVMMDEVREQLOCK *ppLock)
+{
+    VMMDevHGCMCall *pReq = (VMMDevHGCMCall *)pReqHdr;
+    AssertMsgReturn(pReq->header.header.size >= sizeof(*pReq), ("%u\n", pReq->header.header.size), VERR_INVALID_PARAMETER);
+
+    if (pThis->pHGCMDrv)
+    {
+        Log2(("VMMDevReq_HGCMCall: sizeof(VMMDevHGCMRequest) = %04X\n", sizeof(VMMDevHGCMCall)));
+        Log2(("%.*Rhxd\n", pReq->header.header.size, pReq));
+
+        return vmmdevHGCMCall(pThis, pReq, pReq->header.header.size, GCPhysReqHdr, pReq->header.header.requestType,
+                              tsArrival, ppLock);
+    }
+
+    Log(("VMMDevReq_HGCMCall: HGCM Connector is NULL!\n"));
+    return VERR_NOT_SUPPORTED;
+}
+
+/**
+ * Handles VMMDevReq_HGCMCancel.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ * @param   GCPhysReqHdr    The guest physical address of the request header.
+ */
+static int vmmdevReqHandler_HGCMCancel(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr, RTGCPHYS GCPhysReqHdr)
+{
+    VMMDevHGCMCancel *pReq = (VMMDevHGCMCancel *)pReqHdr;
+    AssertMsgReturn(pReq->header.header.size >= sizeof(*pReq), ("%u\n", pReq->header.header.size), VERR_INVALID_PARAMETER);  /** @todo Not sure why this >= ... */
+
+    if (pThis->pHGCMDrv)
+    {
+        Log(("VMMDevReq_VMMDevHGCMCancel\n"));
+        return vmmdevHGCMCancel(pThis, pReq, GCPhysReqHdr);
+    }
+
+    Log(("VMMDevReq_VMMDevHGCMCancel: HGCM Connector is NULL!\n"));
+    return VERR_NOT_SUPPORTED;
+}
+
+
+/**
+ * Handles VMMDevReq_HGCMCancel2.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_HGCMCancel2(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevHGCMCancel2 *pReq = (VMMDevHGCMCancel2 *)pReqHdr;
+    AssertMsgReturn(pReq->header.size >= sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);  /** @todo Not sure why this >= ... */
+
+    if (pThis->pHGCMDrv)
+    {
+        Log(("VMMDevReq_HGCMCancel2\n"));
+        return vmmdevHGCMCancel2(pThis, pReq->physReqToCancel);
+    }
+
+    Log(("VMMDevReq_HGCMCancel2: HGCM Connector is NULL!\n"));
+    return VERR_NOT_SUPPORTED;
+}
+
+#endif /* VBOX_WITH_HGCM */
+
+
+/**
+ * Handles VMMDevReq_VideoAccelEnable.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_VideoAccelEnable(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevVideoAccelEnable *pReq = (VMMDevVideoAccelEnable *)pReqHdr;
+    AssertMsgReturn(pReq->header.size >= sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);  /** @todo Not sure why this >= ... */
+
+    if (!pThis->pDrv)
+    {
+        Log(("VMMDevReq_VideoAccelEnable Connector is NULL!!\n"));
+        return VERR_NOT_SUPPORTED;
+    }
+
+    if (pReq->cbRingBuffer != VMMDEV_VBVA_RING_BUFFER_SIZE)
+    {
+        /* The guest driver seems compiled with different headers. */
+        LogRelMax(16,("VMMDevReq_VideoAccelEnable guest ring buffer size %#x, should be %#x!!\n", pReq->cbRingBuffer, VMMDEV_VBVA_RING_BUFFER_SIZE));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /* The request is correct. */
+    pReq->fu32Status |= VBVA_F_STATUS_ACCEPTED;
+
+    LogFlow(("VMMDevReq_VideoAccelEnable pReq->u32Enable = %d\n", pReq->u32Enable));
+
+    int rc = pReq->u32Enable
+           ? pThis->pDrv->pfnVideoAccelEnable(pThis->pDrv, true, &pThis->pVMMDevRAMR3->vbvaMemory)
+           : pThis->pDrv->pfnVideoAccelEnable(pThis->pDrv, false, NULL);
+
+    if (   pReq->u32Enable
+        && RT_SUCCESS(rc))
+    {
+        pReq->fu32Status |= VBVA_F_STATUS_ENABLED;
+
+        /* Remember that guest successfully enabled acceleration.
+         * We need to reestablish it on restoring the VM from saved state.
+         */
+        pThis->u32VideoAccelEnabled = 1;
+    }
+    else
+    {
+        /* The acceleration was not enabled. Remember that. */
+        pThis->u32VideoAccelEnabled = 0;
+    }
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_VideoAccelFlush.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_VideoAccelFlush(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevVideoAccelFlush *pReq = (VMMDevVideoAccelFlush *)pReqHdr;
+    AssertMsgReturn(pReq->header.size >= sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);  /** @todo Not sure why this >= ... */
+
+    if (!pThis->pDrv)
+    {
+        Log(("VMMDevReq_VideoAccelFlush: Connector is NULL!!!\n"));
+        return VERR_NOT_SUPPORTED;
+    }
+
+    pThis->pDrv->pfnVideoAccelFlush(pThis->pDrv);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_VideoSetVisibleRegion.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_VideoSetVisibleRegion(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevVideoSetVisibleRegion *pReq = (VMMDevVideoSetVisibleRegion *)pReqHdr;
+    AssertMsgReturn(pReq->header.size + sizeof(RTRECT) >= sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    if (!pThis->pDrv)
+    {
+        Log(("VMMDevReq_VideoSetVisibleRegion: Connector is NULL!!!\n"));
+        return VERR_NOT_SUPPORTED;
+    }
+
+    if (   pReq->cRect > _1M /* restrict to sane range */
+        || pReq->header.size != sizeof(VMMDevVideoSetVisibleRegion) + pReq->cRect * sizeof(RTRECT) - sizeof(RTRECT))
+    {
+        Log(("VMMDevReq_VideoSetVisibleRegion: cRects=%#x doesn't match size=%#x or is out of bounds\n",
+             pReq->cRect, pReq->header.size));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    Log(("VMMDevReq_VideoSetVisibleRegion %d rectangles\n", pReq->cRect));
+    /* forward the call */
+    return pThis->pDrv->pfnSetVisibleRegion(pThis->pDrv, pReq->cRect, &pReq->Rect);
+}
+
+
+/**
+ * Handles VMMDevReq_GetSeamlessChangeRequest.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_GetSeamlessChangeRequest(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevSeamlessChangeRequest *pReq = (VMMDevSeamlessChangeRequest *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    /* just pass on the information */
+    Log(("VMMDev: returning seamless change request mode=%d\n", pThis->fSeamlessEnabled));
+    if (pThis->fSeamlessEnabled)
+        pReq->mode = VMMDev_Seamless_Visible_Region;
+    else
+        pReq->mode = VMMDev_Seamless_Disabled;
+
+    if (pReq->eventAck == VMMDEV_EVENT_SEAMLESS_MODE_CHANGE_REQUEST)
+    {
+        /* Remember which mode the client has queried. */
+        pThis->fLastSeamlessEnabled = pThis->fSeamlessEnabled;
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_GetVRDPChangeRequest.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_GetVRDPChangeRequest(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevVRDPChangeRequest *pReq = (VMMDevVRDPChangeRequest *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    /* just pass on the information */
+    Log(("VMMDev: returning VRDP status %d level %d\n", pThis->fVRDPEnabled, pThis->uVRDPExperienceLevel));
+
+    pReq->u8VRDPActive = pThis->fVRDPEnabled;
+    pReq->u32VRDPExperienceLevel = pThis->uVRDPExperienceLevel;
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_GetMemBalloonChangeRequest.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_GetMemBalloonChangeRequest(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevGetMemBalloonChangeRequest *pReq = (VMMDevGetMemBalloonChangeRequest *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    /* just pass on the information */
+    Log(("VMMDev: returning memory balloon size =%d\n", pThis->cMbMemoryBalloon));
+    pReq->cBalloonChunks = pThis->cMbMemoryBalloon;
+    pReq->cPhysMemChunks = pThis->cbGuestRAM / (uint64_t)_1M;
+
+    if (pReq->eventAck == VMMDEV_EVENT_BALLOON_CHANGE_REQUEST)
+    {
+        /* Remember which mode the client has queried. */
+        pThis->cMbMemoryBalloonLast = pThis->cMbMemoryBalloon;
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_ChangeMemBalloon.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_ChangeMemBalloon(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevChangeMemBalloon *pReq = (VMMDevChangeMemBalloon *)pReqHdr;
+    AssertMsgReturn(pReq->header.size >= sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(pReq->cPages      == VMMDEV_MEMORY_BALLOON_CHUNK_PAGES, ("%u\n", pReq->cPages), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(pReq->header.size == (uint32_t)RT_UOFFSETOF_DYN(VMMDevChangeMemBalloon, aPhysPage[pReq->cPages]),
+                    ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    Log(("VMMDevReq_ChangeMemBalloon\n"));
+    int rc = PGMR3PhysChangeMemBalloon(PDMDevHlpGetVM(pThis->pDevInsR3), !!pReq->fInflate, pReq->cPages, pReq->aPhysPage);
+    if (pReq->fInflate)
+        STAM_REL_U32_INC(&pThis->StatMemBalloonChunks);
+    else
+        STAM_REL_U32_DEC(&pThis->StatMemBalloonChunks);
+    return rc;
+}
+
+
+/**
+ * Handles VMMDevReq_GetStatisticsChangeRequest.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_GetStatisticsChangeRequest(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevGetStatisticsChangeRequest *pReq = (VMMDevGetStatisticsChangeRequest *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    Log(("VMMDevReq_GetStatisticsChangeRequest\n"));
+    /* just pass on the information */
+    Log(("VMMDev: returning statistics interval %d seconds\n", pThis->u32StatIntervalSize));
+    pReq->u32StatInterval = pThis->u32StatIntervalSize;
+
+    if (pReq->eventAck == VMMDEV_EVENT_STATISTICS_INTERVAL_CHANGE_REQUEST)
+    {
+        /* Remember which mode the client has queried. */
+        pThis->u32LastStatIntervalSize= pThis->u32StatIntervalSize;
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_ReportGuestStats.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_ReportGuestStats(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevReportGuestStats *pReq = (VMMDevReportGuestStats *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    Log(("VMMDevReq_ReportGuestStats\n"));
+#ifdef LOG_ENABLED
+    VBoxGuestStatistics *pGuestStats = &pReq->guestStats;
+
+    Log(("Current statistics:\n"));
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_CPU_LOAD_IDLE)
+        Log(("CPU%u: CPU Load Idle          %-3d%%\n", pGuestStats->u32CpuId, pGuestStats->u32CpuLoad_Idle));
+
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_CPU_LOAD_KERNEL)
+        Log(("CPU%u: CPU Load Kernel        %-3d%%\n", pGuestStats->u32CpuId, pGuestStats->u32CpuLoad_Kernel));
+
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_CPU_LOAD_USER)
+        Log(("CPU%u: CPU Load User          %-3d%%\n", pGuestStats->u32CpuId, pGuestStats->u32CpuLoad_User));
+
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_THREADS)
+        Log(("CPU%u: Thread                 %d\n", pGuestStats->u32CpuId, pGuestStats->u32Threads));
+
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_PROCESSES)
+        Log(("CPU%u: Processes              %d\n", pGuestStats->u32CpuId, pGuestStats->u32Processes));
+
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_HANDLES)
+        Log(("CPU%u: Handles                %d\n", pGuestStats->u32CpuId, pGuestStats->u32Handles));
+
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_MEMORY_LOAD)
+        Log(("CPU%u: Memory Load            %d%%\n", pGuestStats->u32CpuId, pGuestStats->u32MemoryLoad));
+
+    /* Note that reported values are in pages; upper layers expect them in megabytes */
+    Log(("CPU%u: Page size              %-4d bytes\n", pGuestStats->u32CpuId, pGuestStats->u32PageSize));
+    Assert(pGuestStats->u32PageSize == 4096);
+
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_PHYS_MEM_TOTAL)
+        Log(("CPU%u: Total physical memory  %-4d MB\n", pGuestStats->u32CpuId, (pGuestStats->u32PhysMemTotal + (_1M/_4K)-1) / (_1M/_4K)));
+
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_PHYS_MEM_AVAIL)
+        Log(("CPU%u: Free physical memory   %-4d MB\n", pGuestStats->u32CpuId, pGuestStats->u32PhysMemAvail / (_1M/_4K)));
+
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_PHYS_MEM_BALLOON)
+        Log(("CPU%u: Memory balloon size    %-4d MB\n", pGuestStats->u32CpuId, pGuestStats->u32PhysMemBalloon / (_1M/_4K)));
+
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_MEM_COMMIT_TOTAL)
+        Log(("CPU%u: Committed memory       %-4d MB\n", pGuestStats->u32CpuId, pGuestStats->u32MemCommitTotal / (_1M/_4K)));
+
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_MEM_KERNEL_TOTAL)
+        Log(("CPU%u: Total kernel memory    %-4d MB\n", pGuestStats->u32CpuId, pGuestStats->u32MemKernelTotal / (_1M/_4K)));
+
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_MEM_KERNEL_PAGED)
+        Log(("CPU%u: Paged kernel memory    %-4d MB\n", pGuestStats->u32CpuId, pGuestStats->u32MemKernelPaged / (_1M/_4K)));
+
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_MEM_KERNEL_NONPAGED)
+        Log(("CPU%u: Nonpaged kernel memory %-4d MB\n", pGuestStats->u32CpuId, pGuestStats->u32MemKernelNonPaged / (_1M/_4K)));
+
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_MEM_SYSTEM_CACHE)
+        Log(("CPU%u: System cache size      %-4d MB\n", pGuestStats->u32CpuId, pGuestStats->u32MemSystemCache / (_1M/_4K)));
+
+    if (pGuestStats->u32StatCaps & VBOX_GUEST_STAT_PAGE_FILE_SIZE)
+        Log(("CPU%u: Page file size         %-4d MB\n", pGuestStats->u32CpuId, pGuestStats->u32PageFileSize / (_1M/_4K)));
+    Log(("Statistics end *******************\n"));
+#endif /* LOG_ENABLED */
+
+    /* forward the call */
+    return pThis->pDrv->pfnReportStatistics(pThis->pDrv, &pReq->guestStats);
+}
+
+
+/**
+ * Handles VMMDevReq_QueryCredentials.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_QueryCredentials(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevCredentials *pReq = (VMMDevCredentials *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    /* let's start by nulling out the data */
+    memset(pReq->szUserName, '\0', VMMDEV_CREDENTIALS_SZ_SIZE);
+    memset(pReq->szPassword, '\0', VMMDEV_CREDENTIALS_SZ_SIZE);
+    memset(pReq->szDomain, '\0', VMMDEV_CREDENTIALS_SZ_SIZE);
+
+    /* should we return whether we got credentials for a logon? */
+    if (pReq->u32Flags & VMMDEV_CREDENTIALS_QUERYPRESENCE)
+    {
+        if (   pThis->pCredentials->Logon.szUserName[0]
+            || pThis->pCredentials->Logon.szPassword[0]
+            || pThis->pCredentials->Logon.szDomain[0])
+            pReq->u32Flags |= VMMDEV_CREDENTIALS_PRESENT;
+        else
+            pReq->u32Flags &= ~VMMDEV_CREDENTIALS_PRESENT;
+    }
+
+    /* does the guest want to read logon credentials? */
+    if (pReq->u32Flags & VMMDEV_CREDENTIALS_READ)
+    {
+        if (pThis->pCredentials->Logon.szUserName[0])
+            strcpy(pReq->szUserName, pThis->pCredentials->Logon.szUserName);
+        if (pThis->pCredentials->Logon.szPassword[0])
+            strcpy(pReq->szPassword, pThis->pCredentials->Logon.szPassword);
+        if (pThis->pCredentials->Logon.szDomain[0])
+            strcpy(pReq->szDomain, pThis->pCredentials->Logon.szDomain);
+        if (!pThis->pCredentials->Logon.fAllowInteractiveLogon)
+            pReq->u32Flags |= VMMDEV_CREDENTIALS_NOLOCALLOGON;
+        else
+            pReq->u32Flags &= ~VMMDEV_CREDENTIALS_NOLOCALLOGON;
+    }
+
+    if (!pThis->fKeepCredentials)
+    {
+        /* does the caller want us to destroy the logon credentials? */
+        if (pReq->u32Flags & VMMDEV_CREDENTIALS_CLEAR)
+        {
+            memset(pThis->pCredentials->Logon.szUserName, '\0', VMMDEV_CREDENTIALS_SZ_SIZE);
+            memset(pThis->pCredentials->Logon.szPassword, '\0', VMMDEV_CREDENTIALS_SZ_SIZE);
+            memset(pThis->pCredentials->Logon.szDomain, '\0', VMMDEV_CREDENTIALS_SZ_SIZE);
+        }
+    }
+
+    /* does the guest want to read credentials for verification? */
+    if (pReq->u32Flags & VMMDEV_CREDENTIALS_READJUDGE)
+    {
+        if (pThis->pCredentials->Judge.szUserName[0])
+            strcpy(pReq->szUserName, pThis->pCredentials->Judge.szUserName);
+        if (pThis->pCredentials->Judge.szPassword[0])
+            strcpy(pReq->szPassword, pThis->pCredentials->Judge.szPassword);
+        if (pThis->pCredentials->Judge.szDomain[0])
+            strcpy(pReq->szDomain, pThis->pCredentials->Judge.szDomain);
+    }
+
+    /* does the caller want us to destroy the judgement credentials? */
+    if (pReq->u32Flags & VMMDEV_CREDENTIALS_CLEARJUDGE)
+    {
+        memset(pThis->pCredentials->Judge.szUserName, '\0', VMMDEV_CREDENTIALS_SZ_SIZE);
+        memset(pThis->pCredentials->Judge.szPassword, '\0', VMMDEV_CREDENTIALS_SZ_SIZE);
+        memset(pThis->pCredentials->Judge.szDomain, '\0', VMMDEV_CREDENTIALS_SZ_SIZE);
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_ReportCredentialsJudgement.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_ReportCredentialsJudgement(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevCredentials *pReq = (VMMDevCredentials *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    /* what does the guest think about the credentials? (note: the order is important here!) */
+    if (pReq->u32Flags & VMMDEV_CREDENTIALS_JUDGE_DENY)
+        pThis->pDrv->pfnSetCredentialsJudgementResult(pThis->pDrv, VMMDEV_CREDENTIALS_JUDGE_DENY);
+    else if (pReq->u32Flags & VMMDEV_CREDENTIALS_JUDGE_NOJUDGEMENT)
+        pThis->pDrv->pfnSetCredentialsJudgementResult(pThis->pDrv, VMMDEV_CREDENTIALS_JUDGE_NOJUDGEMENT);
+    else if (pReq->u32Flags & VMMDEV_CREDENTIALS_JUDGE_OK)
+        pThis->pDrv->pfnSetCredentialsJudgementResult(pThis->pDrv, VMMDEV_CREDENTIALS_JUDGE_OK);
+    else
+    {
+        Log(("VMMDevReq_ReportCredentialsJudgement: invalid flags: %d!!!\n", pReq->u32Flags));
+        /** @todo why don't we return VERR_INVALID_PARAMETER to the guest? */
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_GetHostVersion.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pReqHdr         The header of the request to handle.
+ * @since   3.1.0
+ * @note    The ring-0 VBoxGuestLib uses this to check whether
+ *          VMMDevHGCMParmType_PageList is supported.
+ */
+static int vmmdevReqHandler_GetHostVersion(VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevReqHostVersion *pReq = (VMMDevReqHostVersion *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    pReq->major     = RTBldCfgVersionMajor();
+    pReq->minor     = RTBldCfgVersionMinor();
+    pReq->build     = RTBldCfgVersionBuild();
+    pReq->revision  = RTBldCfgRevision();
+    pReq->features  = VMMDEV_HVF_HGCM_PHYS_PAGE_LIST
+                    | VMMDEV_HVF_HGCM_EMBEDDED_BUFFERS
+                    | VMMDEV_HVF_HGCM_CONTIGUOUS_PAGE_LIST
+                    | VMMDEV_HVF_FAST_IRQ_ACK;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_GetCpuHotPlugRequest.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_GetCpuHotPlugRequest(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevGetCpuHotPlugRequest *pReq = (VMMDevGetCpuHotPlugRequest *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    pReq->enmEventType  = pThis->enmCpuHotPlugEvent;
+    pReq->idCpuCore     = pThis->idCpuCore;
+    pReq->idCpuPackage  = pThis->idCpuPackage;
+
+    /* Clear the event */
+    pThis->enmCpuHotPlugEvent = VMMDevCpuEventType_None;
+    pThis->idCpuCore          = UINT32_MAX;
+    pThis->idCpuPackage       = UINT32_MAX;
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_SetCpuHotPlugStatus.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_SetCpuHotPlugStatus(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevCpuHotPlugStatusRequest *pReq = (VMMDevCpuHotPlugStatusRequest *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    if (pReq->enmStatusType == VMMDevCpuStatusType_Disable)
+        pThis->fCpuHotPlugEventsEnabled = false;
+    else if (pReq->enmStatusType == VMMDevCpuStatusType_Enable)
+        pThis->fCpuHotPlugEventsEnabled = true;
+    else
+        return VERR_INVALID_PARAMETER;
+    return VINF_SUCCESS;
+}
+
+
+#ifdef DEBUG
+/**
+ * Handles VMMDevReq_LogString.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_LogString(VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevReqLogString *pReq = (VMMDevReqLogString *)pReqHdr;
+    AssertMsgReturn(pReq->header.size >= sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(pReq->szString[pReq->header.size - RT_UOFFSETOF(VMMDevReqLogString, szString) - 1] == '\0',
+                    ("not null terminated\n"), VERR_INVALID_PARAMETER);
+
+    LogIt(RTLOGGRPFLAGS_LEVEL_1, LOG_GROUP_DEV_VMM_BACKDOOR, ("DEBUG LOG: %s", pReq->szString));
+    return VINF_SUCCESS;
+}
+#endif /* DEBUG */
+
+/**
+ * Handles VMMDevReq_GetSessionId.
+ *
+ * Get a unique "session" ID for this VM, where the ID will be different after each
+ * start, reset or restore of the VM.  This can be used for restore detection
+ * inside the guest.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_GetSessionId(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevReqSessionId *pReq = (VMMDevReqSessionId *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(*pReq), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    pReq->idSession = pThis->idSession;
+    return VINF_SUCCESS;
+}
+
+
+#ifdef VBOX_WITH_PAGE_SHARING
+
+/**
+ * Handles VMMDevReq_RegisterSharedModule.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_RegisterSharedModule(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    /*
+     * Basic input validation (more done by GMM).
+     */
+    VMMDevSharedModuleRegistrationRequest *pReq = (VMMDevSharedModuleRegistrationRequest *)pReqHdr;
+    AssertMsgReturn(pReq->header.size >= sizeof(VMMDevSharedModuleRegistrationRequest),
+                    ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(pReq->header.size == RT_UOFFSETOF_DYN(VMMDevSharedModuleRegistrationRequest, aRegions[pReq->cRegions]),
+                    ("%u cRegions=%u\n", pReq->header.size, pReq->cRegions), VERR_INVALID_PARAMETER);
+
+    AssertReturn(RTStrEnd(pReq->szName, sizeof(pReq->szName)), VERR_INVALID_PARAMETER);
+    AssertReturn(RTStrEnd(pReq->szVersion, sizeof(pReq->szVersion)), VERR_INVALID_PARAMETER);
+    int rc = RTStrValidateEncoding(pReq->szName);
+    AssertRCReturn(rc, rc);
+    rc = RTStrValidateEncoding(pReq->szVersion);
+    AssertRCReturn(rc, rc);
+
+    /*
+     * Forward the request to the VMM.
+     */
+    return PGMR3SharedModuleRegister(PDMDevHlpGetVM(pThis->pDevInsR3), pReq->enmGuestOS, pReq->szName, pReq->szVersion,
+                                     pReq->GCBaseAddr, pReq->cbModule, pReq->cRegions, pReq->aRegions);
+}
+
+/**
+ * Handles VMMDevReq_UnregisterSharedModule.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_UnregisterSharedModule(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    /*
+     * Basic input validation.
+     */
+    VMMDevSharedModuleUnregistrationRequest *pReq = (VMMDevSharedModuleUnregistrationRequest *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(VMMDevSharedModuleUnregistrationRequest),
+                    ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    AssertReturn(RTStrEnd(pReq->szName, sizeof(pReq->szName)), VERR_INVALID_PARAMETER);
+    AssertReturn(RTStrEnd(pReq->szVersion, sizeof(pReq->szVersion)), VERR_INVALID_PARAMETER);
+    int rc = RTStrValidateEncoding(pReq->szName);
+    AssertRCReturn(rc, rc);
+    rc = RTStrValidateEncoding(pReq->szVersion);
+    AssertRCReturn(rc, rc);
+
+    /*
+     * Forward the request to the VMM.
+     */
+    return PGMR3SharedModuleUnregister(PDMDevHlpGetVM(pThis->pDevInsR3), pReq->szName, pReq->szVersion,
+                                       pReq->GCBaseAddr, pReq->cbModule);
+}
+
+/**
+ * Handles VMMDevReq_CheckSharedModules.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_CheckSharedModules(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevSharedModuleCheckRequest *pReq = (VMMDevSharedModuleCheckRequest *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(VMMDevSharedModuleCheckRequest),
+                    ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+    return PGMR3SharedModuleCheckAll(PDMDevHlpGetVM(pThis->pDevInsR3));
+}
+
+/**
+ * Handles VMMDevReq_GetPageSharingStatus.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_GetPageSharingStatus(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevPageSharingStatusRequest *pReq = (VMMDevPageSharingStatusRequest *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(VMMDevPageSharingStatusRequest),
+                    ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    pReq->fEnabled = false;
+    int rc = pThis->pDrv->pfnIsPageFusionEnabled(pThis->pDrv, &pReq->fEnabled);
+    if (RT_FAILURE(rc))
+        pReq->fEnabled = false;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handles VMMDevReq_DebugIsPageShared.
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         The header of the request to handle.
+ */
+static int vmmdevReqHandler_DebugIsPageShared(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevPageIsSharedRequest *pReq = (VMMDevPageIsSharedRequest *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(VMMDevPageIsSharedRequest),
+                    ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+# ifdef DEBUG
+    return PGMR3SharedModuleGetPageState(PDMDevHlpGetVM(pThis->pDevInsR3), pReq->GCPtrPage, &pReq->fShared, &pReq->uPageFlags);
+# else
+    RT_NOREF1(pThis);
+    return VERR_NOT_IMPLEMENTED;
+# endif
+}
+
+#endif /* VBOX_WITH_PAGE_SHARING */
+
+
+/**
+ * Handles VMMDevReq_WriteCoreDumpe
+ *
+ * @returns VBox status code that the guest should see.
+ * @param   pThis           The VMMDev instance data.
+ * @param   pReqHdr         Pointer to the request header.
+ */
+static int vmmdevReqHandler_WriteCoreDump(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr)
+{
+    VMMDevReqWriteCoreDump *pReq = (VMMDevReqWriteCoreDump *)pReqHdr;
+    AssertMsgReturn(pReq->header.size == sizeof(VMMDevReqWriteCoreDump), ("%u\n", pReq->header.size), VERR_INVALID_PARAMETER);
+
+    /*
+     * Only available if explicitly enabled by the user.
+     */
+    if (!pThis->fGuestCoreDumpEnabled)
+        return VERR_ACCESS_DENIED;
+
+    /*
+     * User makes sure the directory exists before composing the path.
+     */
+    if (!RTDirExists(pThis->szGuestCoreDumpDir))
+        return VERR_PATH_NOT_FOUND;
+
+    char szCorePath[RTPATH_MAX];
+    RTStrCopy(szCorePath, sizeof(szCorePath), pThis->szGuestCoreDumpDir);
+    RTPathAppend(szCorePath, sizeof(szCorePath), "VBox.core");
+
+    /*
+     * Rotate existing cores based on number of additional cores to keep around.
+     */
+    if (pThis->cGuestCoreDumps > 0)
+        for (int64_t i = pThis->cGuestCoreDumps - 1; i >= 0; i--)
+        {
+            char szFilePathOld[RTPATH_MAX];
+            if (i == 0)
+                RTStrCopy(szFilePathOld, sizeof(szFilePathOld), szCorePath);
+            else
+                RTStrPrintf(szFilePathOld, sizeof(szFilePathOld), "%s.%lld", szCorePath, i);
+
+            char szFilePathNew[RTPATH_MAX];
+            RTStrPrintf(szFilePathNew, sizeof(szFilePathNew), "%s.%lld", szCorePath, i + 1);
+            int vrc = RTFileMove(szFilePathOld, szFilePathNew, RTFILEMOVE_FLAGS_REPLACE);
+            if (vrc == VERR_FILE_NOT_FOUND)
+                RTFileDelete(szFilePathNew);
+        }
+
+    /*
+     * Write the core file.
+     */
+    PUVM pUVM = PDMDevHlpGetUVM(pThis->pDevInsR3);
+    return DBGFR3CoreWrite(pUVM, szCorePath, true /*fReplaceFile*/);
+}
+
+
+/**
+ * Sets request status to VINF_HGCM_ASYNC_EXECUTE.
+ *
+ * @param   pThis           The VMM device instance data.
+ * @param   GCPhysReqHdr    The guest physical address of the request.
+ * @param   pLock           Pointer to the request locking info.  NULL if not
+ *                          locked.
+ */
+DECLINLINE(void) vmmdevReqHdrSetHgcmAsyncExecute(PVMMDEV pThis, RTGCPHYS GCPhysReqHdr, PVMMDEVREQLOCK pLock)
+{
+    if (pLock)
+        ((VMMDevRequestHeader volatile *)pLock->pvReq)->rc = VINF_HGCM_ASYNC_EXECUTE;
+    else
+    {
+        int32_t rcReq = VINF_HGCM_ASYNC_EXECUTE;
+        PDMDevHlpPhysWrite(pThis->pDevInsR3, GCPhysReqHdr + RT_UOFFSETOF(VMMDevRequestHeader, rc), &rcReq, sizeof(rcReq));
+    }
+}
+
+
+/** @name VMMDEVREQDISP_POST_F_XXX - post dispatcher optimizations.
+ * @{ */
+#define VMMDEVREQDISP_POST_F_NO_WRITE_OUT    RT_BIT_32(0)
+/** @} */
+
+
+/**
+ * Dispatch the request to the appropriate handler function.
+ *
+ * @returns Port I/O handler exit code.
+ * @param   pThis           The VMM device instance data.
+ * @param   pReqHdr         The request header (cached in host memory).
+ * @param   GCPhysReqHdr    The guest physical address of the request (for
+ *                          HGCM).
+ * @param   tsArrival       The STAM_GET_TS() value when the request arrived.
+ * @param   pfPostOptimize  HGCM optimizations, VMMDEVREQDISP_POST_F_XXX.
+ * @param   ppLock          Pointer to the lock info pointer (latter can be
+ *                          NULL).  Set to NULL if HGCM takes lock ownership.
+ */
+static int vmmdevReqDispatcher(PVMMDEV pThis, VMMDevRequestHeader *pReqHdr, RTGCPHYS GCPhysReqHdr,
+                               uint64_t tsArrival, uint32_t *pfPostOptimize, PVMMDEVREQLOCK *ppLock)
+{
+    int rcRet = VINF_SUCCESS;
+    Assert(*pfPostOptimize == 0);
+
+    switch (pReqHdr->requestType)
+    {
+        case VMMDevReq_ReportGuestInfo:
+            pReqHdr->rc = vmmdevReqHandler_ReportGuestInfo(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_ReportGuestInfo2:
+            pReqHdr->rc = vmmdevReqHandler_ReportGuestInfo2(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_ReportGuestStatus:
+            pReqHdr->rc = vmmdevReqHandler_ReportGuestStatus(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_ReportGuestUserState:
+            pReqHdr->rc = vmmdevReqHandler_ReportGuestUserState(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_ReportGuestCapabilities:
+            pReqHdr->rc = vmmdevReqHandler_ReportGuestCapabilities(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_SetGuestCapabilities:
+            pReqHdr->rc = vmmdevReqHandler_SetGuestCapabilities(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_WriteCoreDump:
+            pReqHdr->rc = vmmdevReqHandler_WriteCoreDump(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_GetMouseStatus:
+            pReqHdr->rc = vmmdevReqHandler_GetMouseStatus(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_SetMouseStatus:
+            pReqHdr->rc = vmmdevReqHandler_SetMouseStatus(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_SetPointerShape:
+            pReqHdr->rc = vmmdevReqHandler_SetPointerShape(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_GetHostTime:
+            pReqHdr->rc = vmmdevReqHandler_GetHostTime(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_GetHypervisorInfo:
+            pReqHdr->rc = vmmdevReqHandler_GetHypervisorInfo(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_SetHypervisorInfo:
+            pReqHdr->rc = vmmdevReqHandler_SetHypervisorInfo(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_RegisterPatchMemory:
+            pReqHdr->rc = vmmdevReqHandler_RegisterPatchMemory(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_DeregisterPatchMemory:
+            pReqHdr->rc = vmmdevReqHandler_DeregisterPatchMemory(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_SetPowerStatus:
+        {
+            int rc = pReqHdr->rc = vmmdevReqHandler_SetPowerStatus(pThis, pReqHdr);
+            if (rc != VINF_SUCCESS && RT_SUCCESS(rc))
+                rcRet = rc;
+            break;
+        }
+
+        case VMMDevReq_GetDisplayChangeRequest:
+            pReqHdr->rc = vmmdevReqHandler_GetDisplayChangeRequest(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_GetDisplayChangeRequest2:
+            pReqHdr->rc = vmmdevReqHandler_GetDisplayChangeRequest2(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_GetDisplayChangeRequestEx:
+            pReqHdr->rc = vmmdevReqHandler_GetDisplayChangeRequestEx(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_GetDisplayChangeRequestMulti:
+            pReqHdr->rc = vmmdevReqHandler_GetDisplayChangeRequestMulti(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_VideoModeSupported:
+            pReqHdr->rc = vmmdevReqHandler_VideoModeSupported(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_VideoModeSupported2:
+            pReqHdr->rc = vmmdevReqHandler_VideoModeSupported2(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_GetHeightReduction:
+            pReqHdr->rc = vmmdevReqHandler_GetHeightReduction(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_AcknowledgeEvents:
+            pReqHdr->rc = vmmdevReqHandler_AcknowledgeEvents(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_CtlGuestFilterMask:
+            pReqHdr->rc = vmmdevReqHandler_CtlGuestFilterMask(pThis, pReqHdr);
+            break;
+
+#ifdef VBOX_WITH_HGCM
+        case VMMDevReq_HGCMConnect:
+            vmmdevReqHdrSetHgcmAsyncExecute(pThis, GCPhysReqHdr, *ppLock);
+            pReqHdr->rc = vmmdevReqHandler_HGCMConnect(pThis, pReqHdr, GCPhysReqHdr);
+            Assert(pReqHdr->rc == VINF_HGCM_ASYNC_EXECUTE || RT_FAILURE_NP(pReqHdr->rc));
+            if (RT_SUCCESS(pReqHdr->rc))
+                *pfPostOptimize |= VMMDEVREQDISP_POST_F_NO_WRITE_OUT;
+            break;
+
+        case VMMDevReq_HGCMDisconnect:
+            vmmdevReqHdrSetHgcmAsyncExecute(pThis, GCPhysReqHdr, *ppLock);
+            pReqHdr->rc = vmmdevReqHandler_HGCMDisconnect(pThis, pReqHdr, GCPhysReqHdr);
+            Assert(pReqHdr->rc == VINF_HGCM_ASYNC_EXECUTE || RT_FAILURE_NP(pReqHdr->rc));
+            if (RT_SUCCESS(pReqHdr->rc))
+                *pfPostOptimize |= VMMDEVREQDISP_POST_F_NO_WRITE_OUT;
+            break;
+
+# ifdef VBOX_WITH_64_BITS_GUESTS
+        case VMMDevReq_HGCMCall32:
+        case VMMDevReq_HGCMCall64:
+# else
+        case VMMDevReq_HGCMCall:
+# endif /* VBOX_WITH_64_BITS_GUESTS */
+            vmmdevReqHdrSetHgcmAsyncExecute(pThis, GCPhysReqHdr, *ppLock);
+            pReqHdr->rc = vmmdevReqHandler_HGCMCall(pThis, pReqHdr, GCPhysReqHdr, tsArrival, ppLock);
+            Assert(pReqHdr->rc == VINF_HGCM_ASYNC_EXECUTE || RT_FAILURE_NP(pReqHdr->rc));
+            if (RT_SUCCESS(pReqHdr->rc))
+                *pfPostOptimize |= VMMDEVREQDISP_POST_F_NO_WRITE_OUT;
+            break;
+
+        case VMMDevReq_HGCMCancel:
+            pReqHdr->rc = vmmdevReqHandler_HGCMCancel(pThis, pReqHdr, GCPhysReqHdr);
+            break;
+
+        case VMMDevReq_HGCMCancel2:
+            pReqHdr->rc = vmmdevReqHandler_HGCMCancel2(pThis, pReqHdr);
+            break;
+#endif /* VBOX_WITH_HGCM */
+
+        case VMMDevReq_VideoAccelEnable:
+            pReqHdr->rc = vmmdevReqHandler_VideoAccelEnable(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_VideoAccelFlush:
+            pReqHdr->rc = vmmdevReqHandler_VideoAccelFlush(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_VideoSetVisibleRegion:
+            pReqHdr->rc = vmmdevReqHandler_VideoSetVisibleRegion(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_GetSeamlessChangeRequest:
+            pReqHdr->rc = vmmdevReqHandler_GetSeamlessChangeRequest(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_GetVRDPChangeRequest:
+            pReqHdr->rc = vmmdevReqHandler_GetVRDPChangeRequest(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_GetMemBalloonChangeRequest:
+            pReqHdr->rc = vmmdevReqHandler_GetMemBalloonChangeRequest(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_ChangeMemBalloon:
+            pReqHdr->rc = vmmdevReqHandler_ChangeMemBalloon(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_GetStatisticsChangeRequest:
+            pReqHdr->rc = vmmdevReqHandler_GetStatisticsChangeRequest(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_ReportGuestStats:
+            pReqHdr->rc = vmmdevReqHandler_ReportGuestStats(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_QueryCredentials:
+            pReqHdr->rc = vmmdevReqHandler_QueryCredentials(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_ReportCredentialsJudgement:
+            pReqHdr->rc = vmmdevReqHandler_ReportCredentialsJudgement(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_GetHostVersion:
+            pReqHdr->rc = vmmdevReqHandler_GetHostVersion(pReqHdr);
+            break;
+
+        case VMMDevReq_GetCpuHotPlugRequest:
+            pReqHdr->rc = vmmdevReqHandler_GetCpuHotPlugRequest(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_SetCpuHotPlugStatus:
+            pReqHdr->rc = vmmdevReqHandler_SetCpuHotPlugStatus(pThis, pReqHdr);
+            break;
+
+#ifdef VBOX_WITH_PAGE_SHARING
+        case VMMDevReq_RegisterSharedModule:
+            pReqHdr->rc = vmmdevReqHandler_RegisterSharedModule(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_UnregisterSharedModule:
+            pReqHdr->rc = vmmdevReqHandler_UnregisterSharedModule(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_CheckSharedModules:
+            pReqHdr->rc = vmmdevReqHandler_CheckSharedModules(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_GetPageSharingStatus:
+            pReqHdr->rc = vmmdevReqHandler_GetPageSharingStatus(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_DebugIsPageShared:
+            pReqHdr->rc = vmmdevReqHandler_DebugIsPageShared(pThis, pReqHdr);
+            break;
+
+#endif /* VBOX_WITH_PAGE_SHARING */
+
+#ifdef DEBUG
+        case VMMDevReq_LogString:
+            pReqHdr->rc = vmmdevReqHandler_LogString(pReqHdr);
+            break;
+#endif
+
+        case VMMDevReq_GetSessionId:
+            pReqHdr->rc = vmmdevReqHandler_GetSessionId(pThis, pReqHdr);
+            break;
+
+        /*
+         * Guest wants to give up a timeslice.
+         * Note! This was only ever used by experimental GAs!
+         */
+        /** @todo maybe we could just remove this? */
+        case VMMDevReq_Idle:
+        {
+            /* just return to EMT telling it that we want to halt */
+            rcRet = VINF_EM_HALT;
+            break;
+        }
+
+        case VMMDevReq_GuestHeartbeat:
+            pReqHdr->rc = vmmDevReqHandler_GuestHeartbeat(pThis);
+            break;
+
+        case VMMDevReq_HeartbeatConfigure:
+            pReqHdr->rc = vmmDevReqHandler_HeartbeatConfigure(pThis, pReqHdr);
+            break;
+
+        case VMMDevReq_NtBugCheck:
+            pReqHdr->rc = vmmDevReqHandler_NtBugCheck(pThis, pReqHdr);
+            break;
+
+        default:
+        {
+            pReqHdr->rc = VERR_NOT_IMPLEMENTED;
+            Log(("VMMDev unknown request type %d\n", pReqHdr->requestType));
+            break;
+        }
+    }
+    return rcRet;
+}
+
+
+/**
+ * @callback_method_impl{FNIOMIOPORTOUT,
+ * Port I/O write andler for the generic request interface.}
+ */
+static DECLCALLBACK(int) vmmdevRequestHandler(PPDMDEVINS pDevIns, void *pvUser, RTIOPORT Port, uint32_t u32, unsigned cb)
+{
+    uint64_t tsArrival;
+    STAM_GET_TS(tsArrival);
+
+    RT_NOREF2(Port, cb);
+    PVMMDEV pThis = (VMMDevState *)pvUser;
+
+    /*
+     * The caller has passed the guest context physical address of the request
+     * structure. We'll copy all of it into a heap buffer eventually, but we
+     * will have to start off with the header.
+     */
+    VMMDevRequestHeader requestHeader;
+    RT_ZERO(requestHeader);
+    PDMDevHlpPhysRead(pDevIns, (RTGCPHYS)u32, &requestHeader, sizeof(requestHeader));
+
+    /* The structure size must be greater or equal to the header size. */
+    if (requestHeader.size < sizeof(VMMDevRequestHeader))
+    {
+        Log(("VMMDev request header size too small! size = %d\n", requestHeader.size));
+        return VINF_SUCCESS;
+    }
+
+    /* Check the version of the header structure. */
+    if (requestHeader.version != VMMDEV_REQUEST_HEADER_VERSION)
+    {
+        Log(("VMMDev: guest header version (0x%08X) differs from ours (0x%08X)\n", requestHeader.version, VMMDEV_REQUEST_HEADER_VERSION));
+        return VINF_SUCCESS;
+    }
+
+    Log2(("VMMDev request issued: %d\n", requestHeader.requestType));
+
+    int rcRet = VINF_SUCCESS;
+    /* Check that is doesn't exceed the max packet size. */
+    if (requestHeader.size <= VMMDEV_MAX_VMMDEVREQ_SIZE)
+    {
+        /*
+         * We require the GAs to report it's information before we let it have
+         * access to all the functions.  The VMMDevReq_ReportGuestInfo request
+         * is the one which unlocks the access.  Newer additions will first
+         * issue VMMDevReq_ReportGuestInfo2, older ones doesn't know this one.
+         * Two exceptions: VMMDevReq_GetHostVersion and VMMDevReq_WriteCoreDump.
+         */
+        if (   pThis->fu32AdditionsOk
+            || requestHeader.requestType == VMMDevReq_ReportGuestInfo2
+            || requestHeader.requestType == VMMDevReq_ReportGuestInfo
+            || requestHeader.requestType == VMMDevReq_WriteCoreDump
+            || requestHeader.requestType == VMMDevReq_GetHostVersion
+           )
+        {
+            /*
+             * The request looks fine.  Copy it into a buffer.
+             *
+             * The buffer is only used while on this thread, and this thread is one
+             * of the EMTs, so we keep a 4KB buffer for each EMT around to avoid
+             * wasting time with the heap.  Larger allocations goes to the heap, though.
+             */
+            VMCPUID              iCpu = PDMDevHlpGetCurrentCpuId(pDevIns);
+            VMMDevRequestHeader *pRequestHeaderFree = NULL;
+            VMMDevRequestHeader *pRequestHeader     = NULL;
+            if (   requestHeader.size <= _4K
+                && iCpu < RT_ELEMENTS(pThis->apReqBufs))
+            {
+                pRequestHeader = pThis->apReqBufs[iCpu];
+                if (pRequestHeader)
+                { /* likely */ }
+                else
+                    pThis->apReqBufs[iCpu] = pRequestHeader = (VMMDevRequestHeader *)RTMemPageAlloc(_4K);
+            }
+            else
+            {
+                Assert(iCpu != NIL_VMCPUID);
+                STAM_REL_COUNTER_INC(&pThis->StatReqBufAllocs);
+                pRequestHeaderFree = pRequestHeader = (VMMDevRequestHeader *)RTMemAlloc(RT_MAX(requestHeader.size, 512));
+            }
+            if (pRequestHeader)
+            {
+                memcpy(pRequestHeader, &requestHeader, sizeof(VMMDevRequestHeader));
+
+                /* Try lock the request if it's a HGCM call and not crossing a page boundrary.
+                   Saves on PGM interaction. */
+                VMMDEVREQLOCK   Lock   = { NULL, { 0, NULL } };
+                PVMMDEVREQLOCK  pLock  = NULL;
+                size_t          cbLeft = requestHeader.size - sizeof(VMMDevRequestHeader);
+                if (cbLeft)
+                {
+                    if (   (   requestHeader.requestType == VMMDevReq_HGCMCall32
+                            || requestHeader.requestType == VMMDevReq_HGCMCall64)
+                        && ((u32 + requestHeader.size) >> X86_PAGE_SHIFT) == (u32 >> X86_PAGE_SHIFT)
+                        && RT_SUCCESS(PDMDevHlpPhysGCPhys2CCPtr(pDevIns, u32, 0 /*fFlags*/, &Lock.pvReq, &Lock.Lock)) )
+                    {
+                        memcpy((uint8_t *)pRequestHeader + sizeof(VMMDevRequestHeader),
+                               (uint8_t *)Lock.pvReq     + sizeof(VMMDevRequestHeader), cbLeft);
+                        pLock = &Lock;
+                    }
+                    else
+                        PDMDevHlpPhysRead(pDevIns,
+                                          (RTGCPHYS)u32             + sizeof(VMMDevRequestHeader),
+                                          (uint8_t *)pRequestHeader + sizeof(VMMDevRequestHeader),
+                                          cbLeft);
+                }
+
+                /*
+                 * Feed buffered request thru the dispatcher.
+                 */
+                uint32_t fPostOptimize = 0;
+                PDMCritSectEnter(&pThis->CritSect, VERR_IGNORED);
+                rcRet = vmmdevReqDispatcher(pThis, pRequestHeader, u32, tsArrival, &fPostOptimize, &pLock);
+                PDMCritSectLeave(&pThis->CritSect);
+
+                /*
+                 * Write the result back to guest memory (unless it is a locked HGCM call).
+                 */
+                if (!(fPostOptimize & VMMDEVREQDISP_POST_F_NO_WRITE_OUT))
+                {
+                    if (pLock)
+                        memcpy(pLock->pvReq, pRequestHeader, pRequestHeader->size);
+                    else
+                        PDMDevHlpPhysWrite(pDevIns, u32, pRequestHeader, pRequestHeader->size);
+                }
+
+                if (!pRequestHeaderFree)
+                { /* likely */ }
+                else
+                    RTMemFree(pRequestHeaderFree);
+                return rcRet;
+            }
+
+            Log(("VMMDev: RTMemAlloc failed!\n"));
+            requestHeader.rc = VERR_NO_MEMORY;
+        }
+        else
+        {
+            LogRelMax(10, ("VMMDev: Guest has not yet reported to us -- refusing operation of request #%d\n",
+                           requestHeader.requestType));
+            requestHeader.rc = VERR_NOT_SUPPORTED;
+        }
+    }
+    else
+    {
+        LogRelMax(50, ("VMMDev: Request packet too big (%x), refusing operation\n", requestHeader.size));
+        requestHeader.rc = VERR_NOT_SUPPORTED;
+    }
+
+    /*
+     * Write the result back to guest memory.
+     */
+    PDMDevHlpPhysWrite(pDevIns, u32, &requestHeader, sizeof(requestHeader));
+
+    return rcRet;
+}
+
+#endif /* IN_RING3 */
+
+
+/**
+ * @callback_method_impl{FNIOMIOPORTOUT, Port I/O write handler for requests
+ * that can be handled w/o going to ring-3.}
+ */
+PDMBOTHCBDECL(int) vmmdevFastRequestHandler(PPDMDEVINS pDevIns, void *pvUser, RTIOPORT Port, uint32_t u32, unsigned cb)
+{
+#ifndef IN_RING3
+# if 0 /* This functionality is offered through reading the port (vmmdevFastRequestIrqAck). Leaving it here for later. */
+    PVMMDEV pThis = (VMMDevState *)pvUser;
+    Assert(PDMINS_2_DATA(pDevIns, PVMMDEV) == pThis);
+    RT_NOREF2(Port, cb);
+
+    /*
+     * We only process a limited set of requests here, reflecting the rest down
+     * to ring-3.  So, try read the whole request into a stack buffer and check
+     * if we can handle it.
+     */
+    union
+    {
+        VMMDevRequestHeader Hdr;
+        VMMDevEvents        Ack;
+    } uReq;
+    RT_ZERO(uReq);
+
+    VBOXSTRICTRC rcStrict;
+    if (pThis->fu32AdditionsOk)
+    {
+        /* Read it into memory. */
+        uint32_t cbToRead = sizeof(uReq); /* (Adjust to stay within a page if we support more than ack requests.) */
+        rcStrict = PDMDevHlpPhysRead(pDevIns, u32, &uReq, cbToRead);
+        if (rcStrict == VINF_SUCCESS)
+        {
+            /*
+             * Validate the request and check that we want to handle it here.
+             */
+            if (   uReq.Hdr.size        >= sizeof(uReq.Hdr)
+                && uReq.Hdr.version     == VMMDEV_REQUEST_HEADER_VERSION
+                && (   uReq.Hdr.requestType == VMMDevReq_AcknowledgeEvents
+                    && uReq.Hdr.size        == sizeof(uReq.Ack)
+                    && cbToRead             == sizeof(uReq.Ack)
+                    && pThis->CTX_SUFF(pVMMDevRAM) != NULL)
+               )
+            {
+                RT_UNTRUSTED_VALIDATED_FENCE();
+
+                /*
+                 * Try grab the critical section.
+                 */
+                int rc2 = PDMCritSectEnter(&pThis->CritSect, VINF_IOM_R3_IOPORT_WRITE);
+                if (rc2 == VINF_SUCCESS)
+                {
+                    /*
+                     * Handle the request and write back the result to the guest.
+                     */
+                    uReq.Hdr.rc = vmmdevReqHandler_AcknowledgeEvents(pThis, &uReq.Hdr);
+
+                    rcStrict = PDMDevHlpPhysWrite(pDevIns, u32, &uReq, uReq.Hdr.size);
+                    PDMCritSectLeave(&pThis->CritSect);
+                    if (rcStrict == VINF_SUCCESS)
+                    { /* likely */ }
+                    else
+                        Log(("vmmdevFastRequestHandler: PDMDevHlpPhysWrite(%#RX32+rc,4) -> %Rrc (%RTbool)\n",
+                             u32, VBOXSTRICTRC_VAL(rcStrict), PGM_PHYS_RW_IS_SUCCESS(rcStrict) ));
+                }
+                else
+                {
+                    Log(("vmmdevFastRequestHandler: PDMCritSectEnter -> %Rrc\n", rc2));
+                    rcStrict = rc2;
+                }
+            }
+            else
+            {
+                Log(("vmmdevFastRequestHandler: size=%#x version=%#x requestType=%d (pVMMDevRAM=%p) -> R3\n",
+                     uReq.Hdr.size, uReq.Hdr.version, uReq.Hdr.requestType, pThis->CTX_SUFF(pVMMDevRAM) ));
+                rcStrict = VINF_IOM_R3_IOPORT_WRITE;
+            }
+        }
+        else
+            Log(("vmmdevFastRequestHandler: PDMDevHlpPhysRead(%#RX32,%#RX32) -> %Rrc\n", u32, cbToRead, VBOXSTRICTRC_VAL(rcStrict)));
+    }
+    else
+    {
+        Log(("vmmdevFastRequestHandler: additions nok-okay\n"));
+        rcStrict = VINF_IOM_R3_IOPORT_WRITE;
+    }
+
+    return VBOXSTRICTRC_VAL(rcStrict);
+# else
+    RT_NOREF(pDevIns, pvUser, Port, u32, cb);
+    return VINF_IOM_R3_IOPORT_WRITE;
+# endif
+
+#else  /* IN_RING3 */
+    return vmmdevRequestHandler(pDevIns, pvUser, Port, u32, cb);
+#endif /* IN_RING3 */
+}
+
+
+/**
+ * @callback_method_impl{FNIOMIOPORTIN,
+ * Port I/O read handler for IRQ acknowledging and getting pending events (same
+ * as VMMDevReq_AcknowledgeEvents - just faster).}
+ */
+PDMBOTHCBDECL(int) vmmdevFastRequestIrqAck(PPDMDEVINS pDevIns, void *pvUser, RTIOPORT Port, uint32_t *pu32, unsigned cb)
+{
+    PVMMDEV pThis = (VMMDevState *)pvUser;
+    Assert(PDMINS_2_DATA(pDevIns, PVMMDEV) == pThis);
+    RT_NOREF(Port);
+
+    /* Only 32-bit accesses. */
+    ASSERT_GUEST_MSG_RETURN(cb == sizeof(uint32_t), ("cb=%d\n", cb), VERR_IOM_IOPORT_UNUSED);
+
+    /* The VMMDev memory mapping might've failed, go to ring-3 in that case. */
+    VBOXSTRICTRC rcStrict;
+#ifndef IN_RING3
+    if (pThis->CTX_SUFF(pVMMDevRAM) != NULL)
+#endif
+    {
+        /* Enter critical section and check that the additions has been properly
+           initialized and that we're not in legacy v1.3 device mode. */
+        rcStrict = PDMCritSectEnter(&pThis->CritSect, VINF_IOM_R3_IOPORT_READ);
+        if (rcStrict == VINF_SUCCESS)
+        {
+            if (   pThis->fu32AdditionsOk
+                && !VMMDEV_INTERFACE_VERSION_IS_1_03(pThis))
+            {
+                /*
+                 * Do the job.
+                 *
+                 * Note! This code is duplicated in vmmdevReqHandler_AcknowledgeEvents.
+                 */
+                STAM_REL_COUNTER_INC(&pThis->CTX_SUFF_Z(StatFastIrqAck));
+
+                if (pThis->fNewGuestFilterMask)
+                {
+                    pThis->fNewGuestFilterMask = false;
+                    pThis->u32GuestFilterMask = pThis->u32NewGuestFilterMask;
+                }
+
+                *pu32 = pThis->u32HostEventFlags & pThis->u32GuestFilterMask;
+
+                pThis->u32HostEventFlags &= ~pThis->u32GuestFilterMask;
+                pThis->CTX_SUFF(pVMMDevRAM)->V.V1_04.fHaveEvents = false;
+
+                PDMDevHlpPCISetIrqNoWait(pDevIns, 0, 0);
+            }
+            else
+            {
+                Log(("vmmdevFastRequestIrqAck: fu32AdditionsOk=%d interfaceVersion=%#x\n", pThis->fu32AdditionsOk,
+                     pThis->guestInfo.interfaceVersion));
+                *pu32 = UINT32_MAX;
+            }
+
+            PDMCritSectLeave(&pThis->CritSect);
+        }
+    }
+#ifndef IN_RING3
+    else
+        rcStrict = VINF_IOM_R3_IOPORT_READ;
+#endif
+    return VBOXSTRICTRC_VAL(rcStrict);
+}
+
+
+
+#ifdef IN_RING3
+
+/* -=-=-=-=-=- PCI Device -=-=-=-=-=- */
+
+
+/**
+ * @callback_method_impl{FNPCIIOREGIONMAP,MMIO/MMIO2 regions}
+ */
+static DECLCALLBACK(int) vmmdevIORAMRegionMap(PPDMDEVINS pDevIns, PPDMPCIDEV pPciDev, uint32_t iRegion,
+                                              RTGCPHYS GCPhysAddress, RTGCPHYS cb, PCIADDRESSSPACE enmType)
+{
+    RT_NOREF1(cb);
+    LogFlow(("vmmdevR3IORAMRegionMap: iRegion=%d GCPhysAddress=%RGp cb=%RGp enmType=%d\n", iRegion, GCPhysAddress, cb, enmType));
+    PVMMDEV pThis = RT_FROM_MEMBER(pPciDev, VMMDEV, PciDev);
+    int rc;
+
+    if (iRegion == 1)
+    {
+        AssertReturn(enmType == PCI_ADDRESS_SPACE_MEM, VERR_INTERNAL_ERROR);
+        Assert(pThis->pVMMDevRAMR3 != NULL);
+        if (GCPhysAddress != NIL_RTGCPHYS)
+        {
+            /*
+             * Map the MMIO2 memory.
+             */
+            pThis->GCPhysVMMDevRAM = GCPhysAddress;
+            Assert(pThis->GCPhysVMMDevRAM == GCPhysAddress);
+            rc = PDMDevHlpMMIOExMap(pDevIns, pPciDev, iRegion, GCPhysAddress);
+        }
+        else
+        {
+            /*
+             * It is about to be unmapped, just clean up.
+             */
+            pThis->GCPhysVMMDevRAM = NIL_RTGCPHYS32;
+            rc = VINF_SUCCESS;
+        }
+    }
+    else if (iRegion == 2)
+    {
+        AssertReturn(enmType == PCI_ADDRESS_SPACE_MEM_PREFETCH, VERR_INTERNAL_ERROR);
+        Assert(pThis->pVMMDevHeapR3 != NULL);
+        if (GCPhysAddress != NIL_RTGCPHYS)
+        {
+            /*
+             * Map the MMIO2 memory.
+             */
+            pThis->GCPhysVMMDevHeap = GCPhysAddress;
+            Assert(pThis->GCPhysVMMDevHeap == GCPhysAddress);
+            rc = PDMDevHlpMMIOExMap(pDevIns, pPciDev, iRegion, GCPhysAddress);
+            if (RT_SUCCESS(rc))
+                rc = PDMDevHlpRegisterVMMDevHeap(pDevIns, GCPhysAddress, pThis->pVMMDevHeapR3, VMMDEV_HEAP_SIZE);
+        }
+        else
+        {
+            /*
+             * It is about to be unmapped, just clean up.
+             */
+            PDMDevHlpRegisterVMMDevHeap(pDevIns, NIL_RTGCPHYS, pThis->pVMMDevHeapR3, VMMDEV_HEAP_SIZE);
+            pThis->GCPhysVMMDevHeap = NIL_RTGCPHYS32;
+            rc = VINF_SUCCESS;
+        }
+    }
+    else
+    {
+        AssertMsgFailed(("%d\n", iRegion));
+        rc = VERR_INVALID_PARAMETER;
+    }
+
+    return rc;
+}
+
+
+/**
+ * @callback_method_impl{FNPCIIOREGIONMAP,I/O Port Region}
+ */
+static DECLCALLBACK(int) vmmdevIOPortRegionMap(PPDMDEVINS pDevIns, PPDMPCIDEV pPciDev, uint32_t iRegion,
+                                               RTGCPHYS GCPhysAddress, RTGCPHYS cb, PCIADDRESSSPACE enmType)
+{
+    LogFlow(("vmmdevIOPortRegionMap: iRegion=%d GCPhysAddress=%RGp cb=%RGp enmType=%d\n", iRegion, GCPhysAddress, cb, enmType));
+    RT_NOREF3(iRegion, cb, enmType);
+    PVMMDEV pThis = RT_FROM_MEMBER(pPciDev, VMMDEV, PciDev);
+
+    Assert(enmType == PCI_ADDRESS_SPACE_IO);
+    Assert(iRegion == 0);
+    AssertMsg(RT_ALIGN(GCPhysAddress, 8) == GCPhysAddress, ("Expected 8 byte alignment. GCPhysAddress=%#x\n", GCPhysAddress));
+
+    /*
+     * Register our port IO handlers.
+     */
+    int rc = PDMDevHlpIOPortRegister(pDevIns, (RTIOPORT)GCPhysAddress + VMMDEV_PORT_OFF_REQUEST, 1,
+                                     pThis, vmmdevRequestHandler, NULL, NULL, NULL, "VMMDev Request Handler");
+    AssertLogRelRCReturn(rc, rc);
+
+    /* The fast one: */
+    rc = PDMDevHlpIOPortRegister(pDevIns, (RTIOPORT)GCPhysAddress + VMMDEV_PORT_OFF_REQUEST_FAST, 1,
+                                 pThis, vmmdevFastRequestHandler, vmmdevFastRequestIrqAck, NULL, NULL, "VMMDev Fast R0/RC Requests");
+    AssertLogRelRCReturn(rc, rc);
+    if (pThis->fRZEnabled)
+    {
+        rc = PDMDevHlpIOPortRegisterR0(pDevIns, (RTIOPORT)GCPhysAddress + VMMDEV_PORT_OFF_REQUEST_FAST, 1,
+                                       PDMINS_2_DATA_R0PTR(pDevIns), "vmmdevFastRequestHandler", "vmmdevFastRequestIrqAck",
+                                       NULL, NULL, "VMMDev Fast R0/RC Requests");
+        AssertLogRelRCReturn(rc, rc);
+        rc = PDMDevHlpIOPortRegisterRC(pDevIns, (RTIOPORT)GCPhysAddress + VMMDEV_PORT_OFF_REQUEST_FAST, 1,
+                                       PDMINS_2_DATA_RCPTR(pDevIns), "vmmdevFastRequestHandler", "vmmdevFastRequestIrqAck",
+                                       NULL, NULL, "VMMDev Fast R0/RC Requests");
+        AssertLogRelRCReturn(rc, rc);
+    }
+
+    return rc;
+}
+
+
+
+/* -=-=-=-=-=- Backdoor Logging and Time Sync. -=-=-=-=-=- */
+
+/**
+ * @callback_method_impl{FNIOMIOPORTOUT, Backdoor Logging.}
+ */
+static DECLCALLBACK(int) vmmdevBackdoorLog(PPDMDEVINS pDevIns, void *pvUser, RTIOPORT Port, uint32_t u32, unsigned cb)
+{
+    RT_NOREF1(pvUser);
+    PVMMDEV pThis = PDMINS_2_DATA(pDevIns, VMMDevState *);
+
+    if (!pThis->fBackdoorLogDisabled && cb == 1 && Port == RTLOG_DEBUG_PORT)
+    {
+
+        /* The raw version. */
+        switch (u32)
+        {
+            case '\r': LogIt(RTLOGGRPFLAGS_LEVEL_2, LOG_GROUP_DEV_VMM_BACKDOOR, ("vmmdev: <return>\n")); break;
+            case '\n': LogIt(RTLOGGRPFLAGS_LEVEL_2, LOG_GROUP_DEV_VMM_BACKDOOR, ("vmmdev: <newline>\n")); break;
+            case '\t': LogIt(RTLOGGRPFLAGS_LEVEL_2, LOG_GROUP_DEV_VMM_BACKDOOR, ("vmmdev: <tab>\n")); break;
+            default:   LogIt(RTLOGGRPFLAGS_LEVEL_2, LOG_GROUP_DEV_VMM_BACKDOOR, ("vmmdev: %c (%02x)\n", u32, u32)); break;
+        }
+
+        /* The readable, buffered version. */
+        if (u32 == '\n' || u32 == '\r')
+        {
+            pThis->szMsg[pThis->iMsg] = '\0';
+            if (pThis->iMsg)
+                LogRelIt(RTLOGGRPFLAGS_LEVEL_1, LOG_GROUP_DEV_VMM_BACKDOOR, ("VMMDev: Guest Log: %s\n", pThis->szMsg));
+            pThis->iMsg = 0;
+        }
+        else
+        {
+            if (pThis->iMsg >= sizeof(pThis->szMsg)-1)
+            {
+                pThis->szMsg[pThis->iMsg] = '\0';
+                LogRelIt(RTLOGGRPFLAGS_LEVEL_1, LOG_GROUP_DEV_VMM_BACKDOOR, ("VMMDev: Guest Log: %s\n", pThis->szMsg));
+                pThis->iMsg = 0;
+            }
+            pThis->szMsg[pThis->iMsg] = (char )u32;
+            pThis->szMsg[++pThis->iMsg] = '\0';
+        }
+    }
+    return VINF_SUCCESS;
+}
+
+#ifdef VMMDEV_WITH_ALT_TIMESYNC
+
+/**
+ * @callback_method_impl{FNIOMIOPORTOUT, Alternative time synchronization.}
+ */
+static DECLCALLBACK(int) vmmdevAltTimeSyncWrite(PPDMDEVINS pDevIns, void *pvUser, RTIOPORT Port, uint32_t u32, unsigned cb)
+{
+    RT_NOREF2(pvUser, Port);
+    PVMMDEV pThis = PDMINS_2_DATA(pDevIns, VMMDevState *);
+    if (cb == 4)
+    {
+        /* Selects high (0) or low (1) DWORD. The high has to be read first. */
+        switch (u32)
+        {
+            case 0:
+                pThis->fTimesyncBackdoorLo = false;
+                break;
+            case 1:
+                pThis->fTimesyncBackdoorLo = true;
+                break;
+            default:
+                Log(("vmmdevAltTimeSyncWrite: Invalid access cb=%#x u32=%#x\n", cb, u32));
+                break;
+        }
+    }
+    else
+        Log(("vmmdevAltTimeSyncWrite: Invalid access cb=%#x u32=%#x\n", cb, u32));
+    return VINF_SUCCESS;
+}
+
+/**
+ * @callback_method_impl{FNIOMIOPORTOUT, Alternative time synchronization.}
+ */
+static DECLCALLBACK(int) vmmdevAltTimeSyncRead(PPDMDEVINS pDevIns, void *pvUser, RTIOPORT Port, uint32_t *pu32, unsigned cb)
+{
+    RT_NOREF2(pvUser, Port);
+    PVMMDEV pThis = PDMINS_2_DATA(pDevIns, VMMDevState *);
+    int     rc;
+    if (cb == 4)
+    {
+        if (pThis->fTimesyncBackdoorLo)
+            *pu32 = (uint32_t)pThis->hostTime;
+        else
+        {
+            /* Reading the high dword gets and saves the current time. */
+            RTTIMESPEC Now;
+            pThis->hostTime = RTTimeSpecGetMilli(PDMDevHlpTMUtcNow(pDevIns, &Now));
+            *pu32 = (uint32_t)(pThis->hostTime >> 32);
+        }
+        rc = VINF_SUCCESS;
+    }
+    else
+    {
+        Log(("vmmdevAltTimeSyncRead: Invalid access cb=%#x\n", cb));
+        rc = VERR_IOM_IOPORT_UNUSED;
+    }
+    return rc;
+}
+
+#endif /* VMMDEV_WITH_ALT_TIMESYNC */
+
+
+/* -=-=-=-=-=- IBase -=-=-=-=-=- */
+
+/**
+ * @interface_method_impl{PDMIBASE,pfnQueryInterface}
+ */
+static DECLCALLBACK(void *) vmmdevPortQueryInterface(PPDMIBASE pInterface, const char *pszIID)
+{
+    PVMMDEV pThis = RT_FROM_MEMBER(pInterface, VMMDEV, IBase);
+
+    PDMIBASE_RETURN_INTERFACE(pszIID, PDMIBASE, &pThis->IBase);
+    PDMIBASE_RETURN_INTERFACE(pszIID, PDMIVMMDEVPORT, &pThis->IPort);
+#ifdef VBOX_WITH_HGCM
+    PDMIBASE_RETURN_INTERFACE(pszIID, PDMIHGCMPORT, &pThis->IHGCMPort);
+#endif
+    /* Currently only for shared folders. */
+    PDMIBASE_RETURN_INTERFACE(pszIID, PDMILEDPORTS, &pThis->SharedFolders.ILeds);
+    return NULL;
+}
+
+
+/* -=-=-=-=-=- ILeds -=-=-=-=-=- */
+
+/**
+ * Gets the pointer to the status LED of a unit.
+ *
+ * @returns VBox status code.
+ * @param   pInterface      Pointer to the interface structure containing the called function pointer.
+ * @param   iLUN            The unit which status LED we desire.
+ * @param   ppLed           Where to store the LED pointer.
+ */
+static DECLCALLBACK(int) vmmdevQueryStatusLed(PPDMILEDPORTS pInterface, unsigned iLUN, PPDMLED *ppLed)
+{
+    PVMMDEV pThis = RT_FROM_MEMBER(pInterface, VMMDEV, SharedFolders.ILeds);
+    if (iLUN == 0) /* LUN 0 is shared folders */
+    {
+        *ppLed = &pThis->SharedFolders.Led;
+        return VINF_SUCCESS;
+    }
+    return VERR_PDM_LUN_NOT_FOUND;
+}
+
+
+/* -=-=-=-=-=- PDMIVMMDEVPORT (VMMDEV::IPort) -=-=-=-=-=- */
+
+/**
+ * @interface_method_impl{PDMIVMMDEVPORT,pfnQueryAbsoluteMouse}
+ */
+static DECLCALLBACK(int) vmmdevIPort_QueryAbsoluteMouse(PPDMIVMMDEVPORT pInterface, int32_t *pxAbs, int32_t *pyAbs)
+{
+    PVMMDEV pThis = RT_FROM_MEMBER(pInterface, VMMDEV, IPort);
+
+    /** @todo at the first sign of trouble in this area, just enter the critsect.
+     * As indicated by the comment below, the atomic reads serves no real purpose
+     * here since we can assume cache coherency protocoles and int32_t alignment
+     * rules making sure we won't see a halfwritten value. */
+    if (pxAbs)
+        *pxAbs = ASMAtomicReadS32(&pThis->mouseXAbs); /* why the atomic read? */
+    if (pyAbs)
+        *pyAbs = ASMAtomicReadS32(&pThis->mouseYAbs);
+
+    return VINF_SUCCESS;
+}
+
+/**
+ * @interface_method_impl{PDMIVMMDEVPORT,pfnSetAbsoluteMouse}
+ */
+static DECLCALLBACK(int) vmmdevIPort_SetAbsoluteMouse(PPDMIVMMDEVPORT pInterface, int32_t xAbs, int32_t yAbs)
+{
+    PVMMDEV pThis = RT_FROM_MEMBER(pInterface, VMMDEV, IPort);
+    PDMCritSectEnter(&pThis->CritSect, VERR_IGNORED);
+
+    if (   pThis->mouseXAbs != xAbs
+        || pThis->mouseYAbs != yAbs)
+    {
+        Log2(("vmmdevIPort_SetAbsoluteMouse : settings absolute position to x = %d, y = %d\n", xAbs, yAbs));
+        pThis->mouseXAbs = xAbs;
+        pThis->mouseYAbs = yAbs;
+        VMMDevNotifyGuest(pThis, VMMDEV_EVENT_MOUSE_POSITION_CHANGED);
+    }
+
+    PDMCritSectLeave(&pThis->CritSect);
+    return VINF_SUCCESS;
+}
+
+/**
+ * @interface_method_impl{PDMIVMMDEVPORT,pfnQueryMouseCapabilities}
+ */
+static DECLCALLBACK(int) vmmdevIPort_QueryMouseCapabilities(PPDMIVMMDEVPORT pInterface, uint32_t *pfCapabilities)
+{
+    PVMMDEV pThis = RT_FROM_MEMBER(pInterface, VMMDEV, IPort);
+    AssertPtrReturn(pfCapabilities, VERR_INVALID_PARAMETER);
+
+    *pfCapabilities = pThis->mouseCapabilities;
+    return VINF_SUCCESS;
+}
+
+/**
+ * @interface_method_impl{PDMIVMMDEVPORT,pfnUpdateMouseCapabilities}
+ */
+static DECLCALLBACK(int)
+vmmdevIPort_UpdateMouseCapabilities(PPDMIVMMDEVPORT pInterface, uint32_t fCapsAdded, uint32_t fCapsRemoved)
+{
+    PVMMDEV pThis = RT_FROM_MEMBER(pInterface, VMMDEV, IPort);
+    PDMCritSectEnter(&pThis->CritSect, VERR_IGNORED);
+
+    uint32_t fOldCaps = pThis->mouseCapabilities;
+    pThis->mouseCapabilities &= ~(fCapsRemoved & VMMDEV_MOUSE_HOST_MASK);
+    pThis->mouseCapabilities |= (fCapsAdded & VMMDEV_MOUSE_HOST_MASK)
+                              | VMMDEV_MOUSE_HOST_RECHECKS_NEEDS_HOST_CURSOR;
+    bool fNotify = fOldCaps != pThis->mouseCapabilities;
+
+    LogRelFlow(("VMMDev: vmmdevIPort_UpdateMouseCapabilities: fCapsAdded=0x%x, fCapsRemoved=0x%x, fNotify=%RTbool\n", fCapsAdded,
+                fCapsRemoved, fNotify));
+
+    if (fNotify)
+        VMMDevNotifyGuest(pThis, VMMDEV_EVENT_MOUSE_CAPABILITIES_CHANGED);
+
+    PDMCritSectLeave(&pThis->CritSect);
+    return VINF_SUCCESS;
+}
+
+static bool vmmdevIsMonitorDefEqual(VMMDevDisplayDef const *pNew, VMMDevDisplayDef const *pOld)
+{
+    bool     fEqual = pNew->idDisplay == pOld->idDisplay;
+
+    fEqual = fEqual && (   !RT_BOOL(pNew->fDisplayFlags & VMMDEV_DISPLAY_ORIGIN)    /* No change. */
+                        || (   RT_BOOL(pOld->fDisplayFlags & VMMDEV_DISPLAY_ORIGIN) /* Old value exists and */
+                            && pNew->xOrigin == pOld->xOrigin                       /* the old is equal to the new. */
+                            && pNew->yOrigin == pOld->yOrigin));
+
+    fEqual = fEqual && (   !RT_BOOL(pNew->fDisplayFlags & VMMDEV_DISPLAY_CX)
+                        || (   RT_BOOL(pOld->fDisplayFlags & VMMDEV_DISPLAY_CX)
+                            && pNew->cx == pOld->cx));
+
+    fEqual = fEqual && (   !RT_BOOL(pNew->fDisplayFlags & VMMDEV_DISPLAY_CY)
+                        || (   RT_BOOL(pOld->fDisplayFlags & VMMDEV_DISPLAY_CY)
+                            && pNew->cy == pOld->cy));
+
+    fEqual = fEqual && (   !RT_BOOL(pNew->fDisplayFlags & VMMDEV_DISPLAY_BPP)
+                        || (   RT_BOOL(pOld->fDisplayFlags & VMMDEV_DISPLAY_BPP)
+                            && pNew->cBitsPerPixel == pOld->cBitsPerPixel));
+
+    fEqual = fEqual && (   RT_BOOL(pNew->fDisplayFlags & VMMDEV_DISPLAY_DISABLED)
+                        == RT_BOOL(pOld->fDisplayFlags & VMMDEV_DISPLAY_DISABLED));
+
+    fEqual = fEqual && (   RT_BOOL(pNew->fDisplayFlags & VMMDEV_DISPLAY_PRIMARY)
+                        == RT_BOOL(pOld->fDisplayFlags & VMMDEV_DISPLAY_PRIMARY));
+
+    return fEqual;
+}
+
+/**
+ * @interface_method_impl{PDMIVMMDEVPORT,pfnRequestDisplayChange}
+ */
+static DECLCALLBACK(int)
+vmmdevIPort_RequestDisplayChange(PPDMIVMMDEVPORT pInterface, uint32_t cDisplays, VMMDevDisplayDef const *paDisplays, bool fForce)
+{
+    int rc = VINF_SUCCESS;
+
+    PVMMDEV pThis = RT_FROM_MEMBER(pInterface, VMMDEV, IPort);
+    bool fNotifyGuest = false;
+
+    PDMCritSectEnter(&pThis->CritSect, VERR_IGNORED);
+
+    uint32_t i;
+    for (i = 0; i < cDisplays; ++i)
+    {
+        VMMDevDisplayDef const *p = &paDisplays[i];
+
+        /* Either one display definition is provided or the display id must be equal to the array index. */
+        AssertBreakStmt(cDisplays == 1 || p->idDisplay == i, rc = VERR_INVALID_PARAMETER);
+        AssertBreakStmt(p->idDisplay < RT_ELEMENTS(pThis->displayChangeData.aRequests), rc = VERR_INVALID_PARAMETER);
+
+        DISPLAYCHANGEREQUEST *pRequest = &pThis->displayChangeData.aRequests[p->idDisplay];
+
+        VMMDevDisplayDef const *pLastRead = &pRequest->lastReadDisplayChangeRequest;
+
+        /* Verify that the new resolution is different and that guest does not yet know about it. */
+        bool const fDifferentResolution = fForce || !vmmdevIsMonitorDefEqual(p, pLastRead);
+
+        LogFunc(("same=%d. New: %dx%d, cBits=%d, id=%d. Old: %dx%d, cBits=%d, id=%d. @%d,%d, Enabled=%d, ChangeOrigin=%d\n",
+                 !fDifferentResolution, p->cx, p->cy, p->cBitsPerPixel, p->idDisplay,
+                 pLastRead->cx, pLastRead->cy, pLastRead->cBitsPerPixel, pLastRead->idDisplay,
+                 p->xOrigin, p->yOrigin,
+                 !RT_BOOL(p->fDisplayFlags & VMMDEV_DISPLAY_DISABLED),
+                 RT_BOOL(p->fDisplayFlags & VMMDEV_DISPLAY_ORIGIN)));
+
+        /* We could validate the information here but hey, the guest can do that as well! */
+        pRequest->displayChangeRequest = *p;
+        pRequest->fPending = fDifferentResolution;
+
+        fNotifyGuest = fNotifyGuest || fDifferentResolution;
+    }
+
+    if (RT_SUCCESS(rc))
+    {
+        if (fNotifyGuest)
+        {
+            for (i = 0; i < RT_ELEMENTS(pThis->displayChangeData.aRequests); ++i)
+            {
+                DISPLAYCHANGEREQUEST *pRequest = &pThis->displayChangeData.aRequests[i];
+                if (pRequest->fPending)
+                {
+                    VMMDevDisplayDef const *p = &pRequest->displayChangeRequest;
+                    LogRel(("VMMDev: SetVideoModeHint: Got a video mode hint (%dx%dx%d)@(%dx%d),(%d;%d) at %d\n",
+                            p->cx, p->cy, p->cBitsPerPixel, p->xOrigin, p->yOrigin,
+                            !RT_BOOL(p->fDisplayFlags & VMMDEV_DISPLAY_DISABLED),
+                            RT_BOOL(p->fDisplayFlags & VMMDEV_DISPLAY_ORIGIN), i));
+                }
+            }
+
+            /* IRQ so the guest knows what's going on */
+            VMMDevNotifyGuest(pThis, VMMDEV_EVENT_DISPLAY_CHANGE_REQUEST);
+        }
+    }
+
+    PDMCritSectLeave(&pThis->CritSect);
+    return rc;
+}
+
+/**
+ * @interface_method_impl{PDMIVMMDEVPORT,pfnRequestSeamlessChange}
+ */
+static DECLCALLBACK(int) vmmdevIPort_RequestSeamlessChange(PPDMIVMMDEVPORT pInterface, bool fEnabled)
+{
+    PVMMDEV pThis = RT_FROM_MEMBER(pInterface, VMMDEV, IPort);
+    PDMCritSectEnter(&pThis->CritSect, VERR_IGNORED);
+
+    /* Verify that the new resolution is different and that guest does not yet know about it. */
+    bool fSameMode = (pThis->fLastSeamlessEnabled == fEnabled);
+
+    Log(("vmmdevIPort_RequestSeamlessChange: same=%d. new=%d\n", fSameMode, fEnabled));
+
+    if (!fSameMode)
+    {
+        /* we could validate the information here but hey, the guest can do that as well! */
+        pThis->fSeamlessEnabled = fEnabled;
+
+        /* IRQ so the guest knows what's going on */
+        VMMDevNotifyGuest(pThis, VMMDEV_EVENT_SEAMLESS_MODE_CHANGE_REQUEST);
+    }
+
+    PDMCritSectLeave(&pThis->CritSect);
+    return VINF_SUCCESS;
+}
+
+/**
+ * @interface_method_impl{PDMIVMMDEVPORT,pfnSetMemoryBalloon}
+ */
+static DECLCALLBACK(int) vmmdevIPort_SetMemoryBalloon(PPDMIVMMDEVPORT pInterface, uint32_t cMbBalloon)
+{
+    PVMMDEV pThis = RT_FROM_MEMBER(pInterface, VMMDEV, IPort);
+    PDMCritSectEnter(&pThis->CritSect, VERR_IGNORED);
+
+    /* Verify that the new resolution is different and that guest does not yet know about it. */
+    Log(("vmmdevIPort_SetMemoryBalloon: old=%u new=%u\n", pThis->cMbMemoryBalloonLast, cMbBalloon));
+    if (pThis->cMbMemoryBalloonLast != cMbBalloon)
+    {
+        /* we could validate the information here but hey, the guest can do that as well! */
+        pThis->cMbMemoryBalloon = cMbBalloon;
+
+        /* IRQ so the guest knows what's going on */
+        VMMDevNotifyGuest(pThis, VMMDEV_EVENT_BALLOON_CHANGE_REQUEST);
+    }
+
+    PDMCritSectLeave(&pThis->CritSect);
+    return VINF_SUCCESS;
+}
+
+/**
+ * @interface_method_impl{PDMIVMMDEVPORT,pfnVRDPChange}
+ */
+static DECLCALLBACK(int) vmmdevIPort_VRDPChange(PPDMIVMMDEVPORT pInterface, bool fVRDPEnabled, uint32_t uVRDPExperienceLevel)
+{
+    PVMMDEV pThis = RT_FROM_MEMBER(pInterface, VMMDEV, IPort);
+    PDMCritSectEnter(&pThis->CritSect, VERR_IGNORED);
+
+    bool fSame = (pThis->fVRDPEnabled == fVRDPEnabled);
+
+    Log(("vmmdevIPort_VRDPChange: old=%d. new=%d\n", pThis->fVRDPEnabled, fVRDPEnabled));
+
+    if (!fSame)
+    {
+        pThis->fVRDPEnabled = fVRDPEnabled;
+        pThis->uVRDPExperienceLevel = uVRDPExperienceLevel;
+
+        VMMDevNotifyGuest(pThis, VMMDEV_EVENT_VRDP);
+    }
+
+    PDMCritSectLeave(&pThis->CritSect);
+    return VINF_SUCCESS;
+}
+
+/**
+ * @interface_method_impl{PDMIVMMDEVPORT,pfnSetStatisticsInterval}
+ */
+static DECLCALLBACK(int) vmmdevIPort_SetStatisticsInterval(PPDMIVMMDEVPORT pInterface, uint32_t cSecsStatInterval)
+{
+    PVMMDEV pThis = RT_FROM_MEMBER(pInterface, VMMDEV, IPort);
+    PDMCritSectEnter(&pThis->CritSect, VERR_IGNORED);
+
+    /* Verify that the new resolution is different and that guest does not yet know about it. */
+    bool fSame = (pThis->u32LastStatIntervalSize == cSecsStatInterval);
+
+    Log(("vmmdevIPort_SetStatisticsInterval: old=%d. new=%d\n", pThis->u32LastStatIntervalSize, cSecsStatInterval));
+
+    if (!fSame)
+    {
+        /* we could validate the information here but hey, the guest can do that as well! */
+        pThis->u32StatIntervalSize = cSecsStatInterval;
+
+        /* IRQ so the guest knows what's going on */
+        VMMDevNotifyGuest(pThis, VMMDEV_EVENT_STATISTICS_INTERVAL_CHANGE_REQUEST);
+    }
+
+    PDMCritSectLeave(&pThis->CritSect);
+    return VINF_SUCCESS;
+}
+
+/**
+ * @interface_method_impl{PDMIVMMDEVPORT,pfnSetCredentials}
+ */
+static DECLCALLBACK(int) vmmdevIPort_SetCredentials(PPDMIVMMDEVPORT pInterface, const char *pszUsername,
+                                                    const char *pszPassword, const char *pszDomain, uint32_t fFlags)
+{
+    PVMMDEV pThis = RT_FROM_MEMBER(pInterface, VMMDEV, IPort);
+    AssertReturn(fFlags & (VMMDEV_SETCREDENTIALS_GUESTLOGON | VMMDEV_SETCREDENTIALS_JUDGE), VERR_INVALID_PARAMETER);
+    size_t const cchUsername = strlen(pszUsername);
+    AssertReturn(cchUsername < VMMDEV_CREDENTIALS_SZ_SIZE, VERR_BUFFER_OVERFLOW);
+    size_t const cchPassword = strlen(pszPassword);
+    AssertReturn(cchPassword < VMMDEV_CREDENTIALS_SZ_SIZE, VERR_BUFFER_OVERFLOW);
+    size_t const cchDomain   = strlen(pszDomain);
+    AssertReturn(cchDomain < VMMDEV_CREDENTIALS_SZ_SIZE, VERR_BUFFER_OVERFLOW);
+
+    PDMCritSectEnter(&pThis->CritSect, VERR_IGNORED);
+
+    /*
+     * Logon mode
+     */
+    if (fFlags & VMMDEV_SETCREDENTIALS_GUESTLOGON)
+    {
+        /* memorize the data */
+        memcpy(pThis->pCredentials->Logon.szUserName, pszUsername, cchUsername);
+        pThis->pCredentials->Logon.szUserName[cchUsername] = '\0';
+        memcpy(pThis->pCredentials->Logon.szPassword, pszPassword, cchPassword);
+        pThis->pCredentials->Logon.szPassword[cchPassword] = '\0';
+        memcpy(pThis->pCredentials->Logon.szDomain,   pszDomain, cchDomain);
+        pThis->pCredentials->Logon.szDomain[cchDomain]     = '\0';
+        pThis->pCredentials->Logon.fAllowInteractiveLogon = !(fFlags & VMMDEV_SETCREDENTIALS_NOLOCALLOGON);
+    }
+    /*
+     * Credentials verification mode?
+     */
+    else
+    {
+        /* memorize the data */
+        memcpy(pThis->pCredentials->Judge.szUserName, pszUsername, cchUsername);
+        pThis->pCredentials->Judge.szUserName[cchUsername] = '\0';
+        memcpy(pThis->pCredentials->Judge.szPassword, pszPassword, cchPassword);
+        pThis->pCredentials->Judge.szPassword[cchPassword] = '\0';
+        memcpy(pThis->pCredentials->Judge.szDomain,   pszDomain,   cchDomain);
+        pThis->pCredentials->Judge.szDomain[cchDomain]     = '\0';
+
+        VMMDevNotifyGuest(pThis, VMMDEV_EVENT_JUDGE_CREDENTIALS);
+    }
+
+    PDMCritSectLeave(&pThis->CritSect);
+    return VINF_SUCCESS;
+}
+
+/**
+ * @interface_method_impl{PDMIVMMDEVPORT,pfnVBVAChange}
+ *
+ * Notification from the Display.  Especially useful when acceleration is
+ * disabled after a video mode change.
+ */
+static DECLCALLBACK(void) vmmdevIPort_VBVAChange(PPDMIVMMDEVPORT pInterface, bool fEnabled)
+{
+    PVMMDEV pThis = RT_FROM_MEMBER(pInterface, VMMDEV, IPort);
+    Log(("vmmdevIPort_VBVAChange: fEnabled = %d\n", fEnabled));
+
+    /* Only used by saved state, which I guess is why we don't bother with locking here. */
+    pThis->u32VideoAccelEnabled = fEnabled;
+}
+
+/**
+ * @interface_method_impl{PDMIVMMDEVPORT,pfnCpuHotUnplug}
+ */
+static DECLCALLBACK(int) vmmdevIPort_CpuHotUnplug(PPDMIVMMDEVPORT pInterface, uint32_t idCpuCore, uint32_t idCpuPackage)
+{
+    PVMMDEV pThis = RT_FROM_MEMBER(pInterface, VMMDEV, IPort);
+    int     rc    = VINF_SUCCESS;
+
+    Log(("vmmdevIPort_CpuHotUnplug: idCpuCore=%u idCpuPackage=%u\n", idCpuCore, idCpuPackage));
+
+    PDMCritSectEnter(&pThis->CritSect, VERR_IGNORED);
+
+    if (pThis->fCpuHotPlugEventsEnabled)
+    {
+        pThis->enmCpuHotPlugEvent = VMMDevCpuEventType_Unplug;
+        pThis->idCpuCore          = idCpuCore;
+        pThis->idCpuPackage       = idCpuPackage;
+        VMMDevNotifyGuest(pThis, VMMDEV_EVENT_CPU_HOTPLUG);
+    }
+    else
+        rc = VERR_VMMDEV_CPU_HOTPLUG_NOT_MONITORED_BY_GUEST;
+
+    PDMCritSectLeave(&pThis->CritSect);
+    return rc;
+}
+
+/**
+ * @interface_method_impl{PDMIVMMDEVPORT,pfnCpuHotPlug}
+ */
+static DECLCALLBACK(int) vmmdevIPort_CpuHotPlug(PPDMIVMMDEVPORT pInterface, uint32_t idCpuCore, uint32_t idCpuPackage)
+{
+    PVMMDEV pThis = RT_FROM_MEMBER(pInterface, VMMDEV, IPort);
+    int     rc    = VINF_SUCCESS;
+
+    Log(("vmmdevCpuPlug: idCpuCore=%u idCpuPackage=%u\n", idCpuCore, idCpuPackage));
+
+    PDMCritSectEnter(&pThis->CritSect, VERR_IGNORED);
+
+    if (pThis->fCpuHotPlugEventsEnabled)
+    {
+        pThis->enmCpuHotPlugEvent = VMMDevCpuEventType_Plug;
+        pThis->idCpuCore          = idCpuCore;
+        pThis->idCpuPackage       = idCpuPackage;
+        VMMDevNotifyGuest(pThis, VMMDEV_EVENT_CPU_HOTPLUG);
+    }
+    else
+        rc = VERR_VMMDEV_CPU_HOTPLUG_NOT_MONITORED_BY_GUEST;
+
+    PDMCritSectLeave(&pThis->CritSect);
+    return rc;
+}
+
+
+/* -=-=-=-=-=- Saved State -=-=-=-=-=- */
+
+/**
+ * @callback_method_impl{FNSSMDEVLIVEEXEC}
+ */
+static DECLCALLBACK(int) vmmdevLiveExec(PPDMDEVINS pDevIns, PSSMHANDLE pSSM, uint32_t uPass)
+{
+    RT_NOREF1(uPass);
+    PVMMDEV pThis = PDMINS_2_DATA(pDevIns, PVMMDEV);
+
+    SSMR3PutBool(pSSM, pThis->fGetHostTimeDisabled);
+    SSMR3PutBool(pSSM, pThis->fBackdoorLogDisabled);
+    SSMR3PutBool(pSSM, pThis->fKeepCredentials);
+    SSMR3PutBool(pSSM, pThis->fHeapEnabled);
+
+    return VINF_SSM_DONT_CALL_AGAIN;
+}
+
+
+/**
+ * @callback_method_impl{FNSSMDEVSAVEEXEC}
+ */
+static DECLCALLBACK(int) vmmdevSaveExec(PPDMDEVINS pDevIns, PSSMHANDLE pSSM)
+{
+    PVMMDEV pThis = PDMINS_2_DATA(pDevIns, PVMMDEV);
+    PDMCritSectEnter(&pThis->CritSect, VERR_IGNORED);
+
+    vmmdevLiveExec(pDevIns, pSSM, SSM_PASS_FINAL);
+
+    SSMR3PutU32(pSSM, pThis->hypervisorSize);
+    SSMR3PutU32(pSSM, pThis->mouseCapabilities);
+    SSMR3PutS32(pSSM, pThis->mouseXAbs);
+    SSMR3PutS32(pSSM, pThis->mouseYAbs);
+
+    SSMR3PutBool(pSSM, pThis->fNewGuestFilterMask);
+    SSMR3PutU32(pSSM, pThis->u32NewGuestFilterMask);
+    SSMR3PutU32(pSSM, pThis->u32GuestFilterMask);
+    SSMR3PutU32(pSSM, pThis->u32HostEventFlags);
+    /* The following is not strictly necessary as PGM restores MMIO2, keeping it for historical reasons. */
+    SSMR3PutMem(pSSM, &pThis->pVMMDevRAMR3->V, sizeof(pThis->pVMMDevRAMR3->V));
+
+    SSMR3PutMem(pSSM, &pThis->guestInfo, sizeof(pThis->guestInfo));
+    SSMR3PutU32(pSSM, pThis->fu32AdditionsOk);
+    SSMR3PutU32(pSSM, pThis->u32VideoAccelEnabled);
+    SSMR3PutBool(pSSM, pThis->displayChangeData.fGuestSentChangeEventAck);
+
+    SSMR3PutU32(pSSM, pThis->guestCaps);
+
+#ifdef VBOX_WITH_HGCM
+    vmmdevHGCMSaveState(pThis, pSSM);
+#endif /* VBOX_WITH_HGCM */
+
+    SSMR3PutU32(pSSM, pThis->fHostCursorRequested);
+
+    SSMR3PutU32(pSSM, pThis->guestInfo2.uFullVersion);
+    SSMR3PutU32(pSSM, pThis->guestInfo2.uRevision);
+    SSMR3PutU32(pSSM, pThis->guestInfo2.fFeatures);
+    SSMR3PutStrZ(pSSM, pThis->guestInfo2.szName);
+    SSMR3PutU32(pSSM, pThis->cFacilityStatuses);
+    for (uint32_t i = 0; i < pThis->cFacilityStatuses; i++)
+    {
+        SSMR3PutU32(pSSM, pThis->aFacilityStatuses[i].enmFacility);
+        SSMR3PutU32(pSSM, pThis->aFacilityStatuses[i].fFlags);
+        SSMR3PutU16(pSSM, (uint16_t)pThis->aFacilityStatuses[i].enmStatus);
+        SSMR3PutS64(pSSM, RTTimeSpecGetNano(&pThis->aFacilityStatuses[i].TimeSpecTS));
+    }
+
+    /* Heartbeat: */
+    SSMR3PutBool(pSSM, pThis->fHeartbeatActive);
+    SSMR3PutBool(pSSM, pThis->fFlatlined);
+    SSMR3PutU64(pSSM, pThis->nsLastHeartbeatTS);
+    TMR3TimerSave(pThis->pFlatlinedTimer, pSSM);
+
+    PDMCritSectLeave(&pThis->CritSect);
+    return VINF_SUCCESS;
+}
+
+/**
+ * @callback_method_impl{FNSSMDEVLOADEXEC}
+ */
+static DECLCALLBACK(int) vmmdevLoadExec(PPDMDEVINS pDevIns, PSSMHANDLE pSSM, uint32_t uVersion, uint32_t uPass)
+{
+    /** @todo The code load code is assuming we're always loaded into a freshly
+     *        constructed VM. */
+    PVMMDEV pThis = PDMINS_2_DATA(pDevIns, PVMMDEV);
+    int     rc;
+
+    if (   uVersion > VMMDEV_SAVED_STATE_VERSION
+        || uVersion < 6)
+        return VERR_SSM_UNSUPPORTED_DATA_UNIT_VERSION;
+
+    /* config */
+    if (uVersion > VMMDEV_SAVED_STATE_VERSION_VBOX_30)
+    {
+        bool f;
+        rc = SSMR3GetBool(pSSM, &f); AssertRCReturn(rc, rc);
+        if (pThis->fGetHostTimeDisabled != f)
+            LogRel(("VMMDev: Config mismatch - fGetHostTimeDisabled: config=%RTbool saved=%RTbool\n", pThis->fGetHostTimeDisabled, f));
+
+        rc = SSMR3GetBool(pSSM, &f); AssertRCReturn(rc, rc);
+        if (pThis->fBackdoorLogDisabled != f)
+            LogRel(("VMMDev: Config mismatch - fBackdoorLogDisabled: config=%RTbool saved=%RTbool\n", pThis->fBackdoorLogDisabled, f));
+
+        rc = SSMR3GetBool(pSSM, &f); AssertRCReturn(rc, rc);
+        if (pThis->fKeepCredentials != f)
+            return SSMR3SetCfgError(pSSM, RT_SRC_POS, N_("Config mismatch - fKeepCredentials: config=%RTbool saved=%RTbool"),
+                                     pThis->fKeepCredentials, f);
+        rc = SSMR3GetBool(pSSM, &f); AssertRCReturn(rc, rc);
+        if (pThis->fHeapEnabled != f)
+            return SSMR3SetCfgError(pSSM, RT_SRC_POS, N_("Config mismatch - fHeapEnabled: config=%RTbool saved=%RTbool"),
+                                    pThis->fHeapEnabled, f);
+    }
+
+    if (uPass != SSM_PASS_FINAL)
+        return VINF_SUCCESS;
+
+    /* state */
+    SSMR3GetU32(pSSM, &pThis->hypervisorSize);
+    SSMR3GetU32(pSSM, &pThis->mouseCapabilities);
+    SSMR3GetS32(pSSM, &pThis->mouseXAbs);
+    SSMR3GetS32(pSSM, &pThis->mouseYAbs);
+
+    SSMR3GetBool(pSSM, &pThis->fNewGuestFilterMask);
+    SSMR3GetU32(pSSM, &pThis->u32NewGuestFilterMask);
+    SSMR3GetU32(pSSM, &pThis->u32GuestFilterMask);
+    SSMR3GetU32(pSSM, &pThis->u32HostEventFlags);
+
+    //SSMR3GetBool(pSSM, &pThis->pVMMDevRAMR3->fHaveEvents);
+    // here be dragons (probably)
+    SSMR3GetMem(pSSM, &pThis->pVMMDevRAMR3->V, sizeof (pThis->pVMMDevRAMR3->V));
+
+    SSMR3GetMem(pSSM, &pThis->guestInfo, sizeof (pThis->guestInfo));
+    SSMR3GetU32(pSSM, &pThis->fu32AdditionsOk);
+    SSMR3GetU32(pSSM, &pThis->u32VideoAccelEnabled);
+    if (uVersion > 10)
+        SSMR3GetBool(pSSM, &pThis->displayChangeData.fGuestSentChangeEventAck);
+
+    rc = SSMR3GetU32(pSSM, &pThis->guestCaps);
+
+    /* Attributes which were temporarily introduced in r30072 */
+    if (uVersion == 7)
+    {
+        uint32_t temp;
+        SSMR3GetU32(pSSM, &temp);
+        rc = SSMR3GetU32(pSSM, &temp);
+    }
+    AssertRCReturn(rc, rc);
+
+#ifdef VBOX_WITH_HGCM
+    rc = vmmdevHGCMLoadState(pThis, pSSM, uVersion);
+    AssertRCReturn(rc, rc);
+#endif /* VBOX_WITH_HGCM */
+
+    if (uVersion >= 10)
+        rc = SSMR3GetU32(pSSM, &pThis->fHostCursorRequested);
+    AssertRCReturn(rc, rc);
+
+    if (uVersion > VMMDEV_SAVED_STATE_VERSION_MISSING_GUEST_INFO_2)
+    {
+        SSMR3GetU32(pSSM, &pThis->guestInfo2.uFullVersion);
+        SSMR3GetU32(pSSM, &pThis->guestInfo2.uRevision);
+        SSMR3GetU32(pSSM, &pThis->guestInfo2.fFeatures);
+        rc = SSMR3GetStrZ(pSSM, &pThis->guestInfo2.szName[0], sizeof(pThis->guestInfo2.szName));
+        AssertRCReturn(rc, rc);
+    }
+
+    if (uVersion > VMMDEV_SAVED_STATE_VERSION_MISSING_FACILITY_STATUSES)
+    {
+        uint32_t cFacilityStatuses;
+        rc = SSMR3GetU32(pSSM, &cFacilityStatuses);
+        AssertRCReturn(rc, rc);
+
+        for (uint32_t i = 0; i < cFacilityStatuses; i++)
+        {
+            uint32_t uFacility, fFlags;
+            uint16_t uStatus;
+            int64_t  iTimeStampNano;
+
+            SSMR3GetU32(pSSM, &uFacility);
+            SSMR3GetU32(pSSM, &fFlags);
+            SSMR3GetU16(pSSM, &uStatus);
+            rc = SSMR3GetS64(pSSM, &iTimeStampNano);
+            AssertRCReturn(rc, rc);
+
+            PVMMDEVFACILITYSTATUSENTRY pEntry = vmmdevGetFacilityStatusEntry(pThis, (VBoxGuestFacilityType)uFacility);
+            AssertLogRelMsgReturn(pEntry,
+                                  ("VMMDev: Ran out of entries restoring the guest facility statuses. Saved state has %u.\n", cFacilityStatuses),
+                                  VERR_OUT_OF_RESOURCES);
+            pEntry->enmStatus = (VBoxGuestFacilityStatus)uStatus;
+            pEntry->fFlags    = fFlags;
+            RTTimeSpecSetNano(&pEntry->TimeSpecTS, iTimeStampNano);
+        }
+    }
+
+    /*
+     * Heartbeat.
+     */
+    if (uVersion >= VMMDEV_SAVED_STATE_VERSION_HEARTBEAT)
+    {
+        SSMR3GetBool(pSSM, (bool *)&pThis->fHeartbeatActive);
+        SSMR3GetBool(pSSM, (bool *)&pThis->fFlatlined);
+        SSMR3GetU64(pSSM, (uint64_t *)&pThis->nsLastHeartbeatTS);
+        rc = TMR3TimerLoad(pThis->pFlatlinedTimer, pSSM);
+        AssertRCReturn(rc, rc);
+        if (pThis->fFlatlined)
+            LogRel(("vmmdevLoadState: Guest has flatlined. Last heartbeat %'RU64 ns before state was saved.\n",
+                    TMTimerGetNano(pThis->pFlatlinedTimer) - pThis->nsLastHeartbeatTS));
+    }
+
+    /*
+     * On a resume, we send the capabilities changed message so
+     * that listeners can sync their state again
+     */
+    Log(("vmmdevLoadState: capabilities changed (%x), informing connector\n", pThis->mouseCapabilities));
+    if (pThis->pDrv)
+    {
+        pThis->pDrv->pfnUpdateMouseCapabilities(pThis->pDrv, pThis->mouseCapabilities);
+        if (uVersion >= 10)
+            pThis->pDrv->pfnUpdatePointerShape(pThis->pDrv,
+                                               /*fVisible=*/!!pThis->fHostCursorRequested,
+                                               /*fAlpha=*/false,
+                                               /*xHot=*/0, /*yHot=*/0,
+                                               /*cx=*/0, /*cy=*/0,
+                                               /*pvShape=*/NULL);
+    }
+
+    if (pThis->fu32AdditionsOk)
+    {
+        vmmdevLogGuestOsInfo(&pThis->guestInfo);
+        if (pThis->pDrv)
+        {
+            if (pThis->guestInfo2.uFullVersion && pThis->pDrv->pfnUpdateGuestInfo2)
+                pThis->pDrv->pfnUpdateGuestInfo2(pThis->pDrv, pThis->guestInfo2.uFullVersion, pThis->guestInfo2.szName,
+                                                 pThis->guestInfo2.uRevision, pThis->guestInfo2.fFeatures);
+            if (pThis->pDrv->pfnUpdateGuestInfo)
+                pThis->pDrv->pfnUpdateGuestInfo(pThis->pDrv, &pThis->guestInfo);
+
+            if (pThis->pDrv->pfnUpdateGuestStatus)
+            {
+                for (uint32_t i = 0; i < pThis->cFacilityStatuses; i++) /* ascending order! */
+                    if (   pThis->aFacilityStatuses[i].enmStatus != VBoxGuestFacilityStatus_Inactive
+                        || !pThis->aFacilityStatuses[i].fFixed)
+                        pThis->pDrv->pfnUpdateGuestStatus(pThis->pDrv,
+                                                          pThis->aFacilityStatuses[i].enmFacility,
+                                                          (uint16_t)pThis->aFacilityStatuses[i].enmStatus,
+                                                          pThis->aFacilityStatuses[i].fFlags,
+                                                          &pThis->aFacilityStatuses[i].TimeSpecTS);
+            }
+        }
+    }
+    if (pThis->pDrv && pThis->pDrv->pfnUpdateGuestCapabilities)
+        pThis->pDrv->pfnUpdateGuestCapabilities(pThis->pDrv, pThis->guestCaps);
+
+    return VINF_SUCCESS;
+}
+
+/**
+ * Load state done callback. Notify guest of restore event.
+ *
+ * @returns VBox status code.
+ * @param   pDevIns    The device instance.
+ * @param   pSSM The handle to the saved state.
+ */
+static DECLCALLBACK(int) vmmdevLoadStateDone(PPDMDEVINS pDevIns, PSSMHANDLE pSSM)
+{
+    RT_NOREF1(pSSM);
+    PVMMDEV pThis = PDMINS_2_DATA(pDevIns, PVMMDEV);
+
+#ifdef VBOX_WITH_HGCM
+    int rc = vmmdevHGCMLoadStateDone(pThis);
+    AssertLogRelRCReturn(rc, rc);
+#endif /* VBOX_WITH_HGCM */
+
+    /* Reestablish the acceleration status. */
+    if (    pThis->u32VideoAccelEnabled
+        &&  pThis->pDrv)
+    {
+        pThis->pDrv->pfnVideoAccelEnable(pThis->pDrv, !!pThis->u32VideoAccelEnabled, &pThis->pVMMDevRAMR3->vbvaMemory);
+    }
+
+    VMMDevNotifyGuest(pThis, VMMDEV_EVENT_RESTORED);
+
+    return VINF_SUCCESS;
+}
+
+
+/* -=-=-=-=- PDMDEVREG -=-=-=-=- */
+
+/**
+ * (Re-)initializes the MMIO2 data.
+ *
+ * @param   pThis           Pointer to the VMMDev instance data.
+ */
+static void vmmdevInitRam(PVMMDEV pThis)
+{
+    memset(pThis->pVMMDevRAMR3, 0, sizeof(VMMDevMemory));
+    pThis->pVMMDevRAMR3->u32Size = sizeof(VMMDevMemory);
+    pThis->pVMMDevRAMR3->u32Version = VMMDEV_MEMORY_VERSION;
+}
+
+
+/**
+ * @interface_method_impl{PDMDEVREG,pfnReset}
+ */
+static DECLCALLBACK(void) vmmdevReset(PPDMDEVINS pDevIns)
+{
+    PVMMDEV pThis = PDMINS_2_DATA(pDevIns, PVMMDEV);
+    PDMCritSectEnter(&pThis->CritSect, VERR_IGNORED);
+
+    /*
+     * Reset the mouse integration feature bits
+     */
+    if (pThis->mouseCapabilities & VMMDEV_MOUSE_GUEST_MASK)
+    {
+        pThis->mouseCapabilities &= ~VMMDEV_MOUSE_GUEST_MASK;
+        /* notify the connector */
+        Log(("vmmdevReset: capabilities changed (%x), informing connector\n", pThis->mouseCapabilities));
+        pThis->pDrv->pfnUpdateMouseCapabilities(pThis->pDrv, pThis->mouseCapabilities);
+    }
+    pThis->fHostCursorRequested = false;
+
+    pThis->hypervisorSize = 0;
+
+    /* re-initialize the VMMDev memory */
+    if (pThis->pVMMDevRAMR3)
+        vmmdevInitRam(pThis);
+
+    /* credentials have to go away (by default) */
+    if (!pThis->fKeepCredentials)
+    {
+        memset(pThis->pCredentials->Logon.szUserName, '\0', VMMDEV_CREDENTIALS_SZ_SIZE);
+        memset(pThis->pCredentials->Logon.szPassword, '\0', VMMDEV_CREDENTIALS_SZ_SIZE);
+        memset(pThis->pCredentials->Logon.szDomain, '\0', VMMDEV_CREDENTIALS_SZ_SIZE);
+    }
+    memset(pThis->pCredentials->Judge.szUserName, '\0', VMMDEV_CREDENTIALS_SZ_SIZE);
+    memset(pThis->pCredentials->Judge.szPassword, '\0', VMMDEV_CREDENTIALS_SZ_SIZE);
+    memset(pThis->pCredentials->Judge.szDomain, '\0', VMMDEV_CREDENTIALS_SZ_SIZE);
+
+    /* Reset means that additions will report again. */
+    const bool fVersionChanged = pThis->fu32AdditionsOk
+                              || pThis->guestInfo.interfaceVersion
+                              || pThis->guestInfo.osType != VBOXOSTYPE_Unknown;
+    if (fVersionChanged)
+        Log(("vmmdevReset: fu32AdditionsOk=%d additionsVersion=%x osType=%#x\n",
+             pThis->fu32AdditionsOk, pThis->guestInfo.interfaceVersion, pThis->guestInfo.osType));
+    pThis->fu32AdditionsOk = false;
+    memset (&pThis->guestInfo, 0, sizeof (pThis->guestInfo));
+    RT_ZERO(pThis->guestInfo2);
+    const bool fCapsChanged = pThis->guestCaps != 0; /* Report transition to 0. */
+    pThis->guestCaps = 0;
+
+    /* Clear facilities. No need to tell Main as it will get a
+       pfnUpdateGuestInfo callback. */
+    RTTIMESPEC TimeStampNow;
+    RTTimeNow(&TimeStampNow);
+    uint32_t iFacility = pThis->cFacilityStatuses;
+    while (iFacility-- > 0)
+    {
+        pThis->aFacilityStatuses[iFacility].enmStatus  = VBoxGuestFacilityStatus_Inactive;
+        pThis->aFacilityStatuses[iFacility].TimeSpecTS = TimeStampNow;
+    }
+
+    /* clear pending display change request. */
+    for (unsigned i = 0; i < RT_ELEMENTS(pThis->displayChangeData.aRequests); i++)
+    {
+        DISPLAYCHANGEREQUEST *pRequest = &pThis->displayChangeData.aRequests[i];
+        memset (&pRequest->lastReadDisplayChangeRequest, 0, sizeof (pRequest->lastReadDisplayChangeRequest));
+    }
+    pThis->displayChangeData.iCurrentMonitor = 0;
+    pThis->displayChangeData.fGuestSentChangeEventAck = false;
+
+    /* disable seamless mode */
+    pThis->fLastSeamlessEnabled = false;
+
+    /* disabled memory ballooning */
+    pThis->cMbMemoryBalloonLast = 0;
+
+    /* disabled statistics updating */
+    pThis->u32LastStatIntervalSize = 0;
+
+#ifdef VBOX_WITH_HGCM
+    /* Clear the "HGCM event enabled" flag so the event can be automatically reenabled.  */
+    pThis->u32HGCMEnabled = 0;
+#endif
+
+    /*
+     * Deactive heartbeat.
+     */
+    if (pThis->fHeartbeatActive)
+    {
+        TMTimerStop(pThis->pFlatlinedTimer);
+        pThis->fFlatlined       = false;
+        pThis->fHeartbeatActive = true;
+    }
+
+    /*
+     * Clear the event variables.
+     *
+     * XXX By design we should NOT clear pThis->u32HostEventFlags because it is designed
+     *     that way so host events do not depend on guest resets. However, the pending
+     *     event flags actually _were_ cleared since ages so we mask out events from
+     *     clearing which we really need to survive the reset. See xtracker 5767.
+     */
+    pThis->u32HostEventFlags    &= VMMDEV_EVENT_DISPLAY_CHANGE_REQUEST;
+    pThis->u32GuestFilterMask    = 0;
+    pThis->u32NewGuestFilterMask = 0;
+    pThis->fNewGuestFilterMask   = 0;
+
+    /*
+     * Call the update functions as required.
+     */
+    if (fVersionChanged && pThis->pDrv && pThis->pDrv->pfnUpdateGuestInfo)
+        pThis->pDrv->pfnUpdateGuestInfo(pThis->pDrv, &pThis->guestInfo);
+    if (fCapsChanged && pThis->pDrv && pThis->pDrv->pfnUpdateGuestCapabilities)
+        pThis->pDrv->pfnUpdateGuestCapabilities(pThis->pDrv, pThis->guestCaps);
+
+    /*
+     * Generate a unique session id for this VM; it will be changed for each start, reset or restore.
+     * This can be used for restore detection inside the guest.
+     */
+    pThis->idSession = ASMReadTSC();
+
+    PDMCritSectLeave(&pThis->CritSect);
+}
+
+
+/**
+ * @interface_method_impl{PDMDEVREG,pfnRelocate}
+ */
+static DECLCALLBACK(void) vmmdevRelocate(PPDMDEVINS pDevIns, RTGCINTPTR offDelta)
+{
+    if (offDelta)
+    {
+        PVMMDEV pThis = PDMINS_2_DATA(pDevIns, PVMMDEV);
+        LogFlow(("vmmdevRelocate: offDelta=%RGv\n", offDelta));
+
+        if (pThis->pVMMDevRAMRC)
+            pThis->pVMMDevRAMRC += offDelta;
+        pThis->pDevInsRC = PDMDEVINS_2_RCPTR(pDevIns);
+    }
+}
+
+
+/**
+ * @interface_method_impl{PDMDEVREG,pfnDestruct}
+ */
+static DECLCALLBACK(int) vmmdevDestruct(PPDMDEVINS pDevIns)
+{
+    PVMMDEV pThis = PDMINS_2_DATA(pDevIns, PVMMDEV);
+    PDMDEV_CHECK_VERSIONS_RETURN(pDevIns);
+
+    /*
+     * Wipe and free the credentials.
+     */
+    if (pThis->pCredentials)
+    {
+        RTMemWipeThoroughly(pThis->pCredentials, sizeof(*pThis->pCredentials), 10);
+        RTMemFree(pThis->pCredentials);
+        pThis->pCredentials = NULL;
+    }
+
+#ifdef VBOX_WITH_HGCM
+    /*
+     * Everything HGCM.
+     */
+    vmmdevHGCMDestroy(pThis);
+#endif
+
+    /*
+     * Free the request buffers.
+     */
+    for (uint32_t iCpu = 0; iCpu < RT_ELEMENTS(pThis->apReqBufs); iCpu++)
+    {
+        pThis->apReqBufs[iCpu] = NULL;
+        RTMemPageFree(pThis->apReqBufs[iCpu], _4K);
+    }
+
+#ifndef VBOX_WITHOUT_TESTING_FEATURES
+    /*
+     * Clean up the testing device.
+     */
+    vmmdevTestingTerminate(pDevIns);
+#endif
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * @interface_method_impl{PDMDEVREG,pfnConstruct}
+ */
+static DECLCALLBACK(int) vmmdevConstruct(PPDMDEVINS pDevIns, int iInstance, PCFGMNODE pCfg)
+{
+    PVMMDEV pThis = PDMINS_2_DATA(pDevIns, PVMMDEV);
+    int rc;
+
+    Assert(iInstance == 0);
+    PDMDEV_CHECK_VERSIONS_RETURN(pDevIns);
+
+    /*
+     * Initialize data (most of it anyway).
+     */
+    /* Save PDM device instance data for future reference. */
+    pThis->pDevInsR3 = pDevIns;
+    pThis->pDevInsR0 = PDMDEVINS_2_R0PTR(pDevIns);
+    pThis->pDevInsRC = PDMDEVINS_2_RCPTR(pDevIns);
+
+    /* PCI vendor, just a free bogus value */
+    PCIDevSetVendorId(&pThis->PciDev, 0x80ee);
+    /* device ID */
+    PCIDevSetDeviceId(&pThis->PciDev, 0xcafe);
+    /* class sub code (other type of system peripheral) */
+    PCIDevSetClassSub(&pThis->PciDev, 0x80);
+    /* class base code (base system peripheral) */
+    PCIDevSetClassBase(&pThis->PciDev, 0x08);
+    /* header type */
+    PCIDevSetHeaderType(&pThis->PciDev, 0x00);
+    /* interrupt on pin 0 */
+    PCIDevSetInterruptPin(&pThis->PciDev, 0x01);
+
+    RTTIMESPEC TimeStampNow;
+    RTTimeNow(&TimeStampNow);
+    vmmdevAllocFacilityStatusEntry(pThis, VBoxGuestFacilityType_VBoxGuestDriver, true /*fFixed*/, &TimeStampNow);
+    vmmdevAllocFacilityStatusEntry(pThis, VBoxGuestFacilityType_VBoxService,     true /*fFixed*/, &TimeStampNow);
+    vmmdevAllocFacilityStatusEntry(pThis, VBoxGuestFacilityType_VBoxTrayClient,  true /*fFixed*/, &TimeStampNow);
+    vmmdevAllocFacilityStatusEntry(pThis, VBoxGuestFacilityType_Seamless,        true /*fFixed*/, &TimeStampNow);
+    vmmdevAllocFacilityStatusEntry(pThis, VBoxGuestFacilityType_Graphics,        true /*fFixed*/, &TimeStampNow);
+    Assert(pThis->cFacilityStatuses == 5);
+
+    /*
+     * Interfaces
+     */
+    /* IBase */
+    pThis->IBase.pfnQueryInterface          = vmmdevPortQueryInterface;
+
+    /* VMMDev port */
+    pThis->IPort.pfnQueryAbsoluteMouse      = vmmdevIPort_QueryAbsoluteMouse;
+    pThis->IPort.pfnSetAbsoluteMouse        = vmmdevIPort_SetAbsoluteMouse ;
+    pThis->IPort.pfnQueryMouseCapabilities  = vmmdevIPort_QueryMouseCapabilities;
+    pThis->IPort.pfnUpdateMouseCapabilities = vmmdevIPort_UpdateMouseCapabilities;
+    pThis->IPort.pfnRequestDisplayChange    = vmmdevIPort_RequestDisplayChange;
+    pThis->IPort.pfnSetCredentials          = vmmdevIPort_SetCredentials;
+    pThis->IPort.pfnVBVAChange              = vmmdevIPort_VBVAChange;
+    pThis->IPort.pfnRequestSeamlessChange   = vmmdevIPort_RequestSeamlessChange;
+    pThis->IPort.pfnSetMemoryBalloon        = vmmdevIPort_SetMemoryBalloon;
+    pThis->IPort.pfnSetStatisticsInterval   = vmmdevIPort_SetStatisticsInterval;
+    pThis->IPort.pfnVRDPChange              = vmmdevIPort_VRDPChange;
+    pThis->IPort.pfnCpuHotUnplug            = vmmdevIPort_CpuHotUnplug;
+    pThis->IPort.pfnCpuHotPlug              = vmmdevIPort_CpuHotPlug;
+
+    /* Shared folder LED */
+    pThis->SharedFolders.Led.u32Magic       = PDMLED_MAGIC;
+    pThis->SharedFolders.ILeds.pfnQueryStatusLed = vmmdevQueryStatusLed;
+
+#ifdef VBOX_WITH_HGCM
+    /* HGCM port */
+    pThis->IHGCMPort.pfnCompleted           = hgcmCompleted;
+    pThis->IHGCMPort.pfnIsCmdRestored       = hgcmIsCmdRestored;
+    pThis->IHGCMPort.pfnIsCmdCancelled      = hgcmIsCmdCancelled;
+    pThis->IHGCMPort.pfnGetRequestor        = hgcmGetRequestor;
+    pThis->IHGCMPort.pfnGetVMMDevSessionId  = hgcmGetVMMDevSessionId;
+#endif
+
+    pThis->pCredentials = (VMMDEVCREDS *)RTMemAllocZ(sizeof(*pThis->pCredentials));
+    if (!pThis->pCredentials)
+        return VERR_NO_MEMORY;
+
+
+    /*
+     * Validate and read the configuration.
+     */
+    PDMDEV_VALIDATE_CONFIG_RETURN(pDevIns,
+                                  "GetHostTimeDisabled|"
+                                  "BackdoorLogDisabled|"
+                                  "KeepCredentials|"
+                                  "HeapEnabled|"
+                                  "RZEnabled|"
+                                  "GuestCoreDumpEnabled|"
+                                  "GuestCoreDumpDir|"
+                                  "GuestCoreDumpCount|"
+                                  "HeartbeatInterval|"
+                                  "HeartbeatTimeout|"
+                                  "TestingEnabled|"
+                                  "TestingMMIO|"
+                                  "TestintXmlOutputFile"
+                                  ,
+                                  "");
+
+    rc = CFGMR3QueryBoolDef(pCfg, "GetHostTimeDisabled", &pThis->fGetHostTimeDisabled, false);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Failed querying \"GetHostTimeDisabled\" as a boolean"));
+
+    rc = CFGMR3QueryBoolDef(pCfg, "BackdoorLogDisabled", &pThis->fBackdoorLogDisabled, false);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Failed querying \"BackdoorLogDisabled\" as a boolean"));
+
+    rc = CFGMR3QueryBoolDef(pCfg, "KeepCredentials", &pThis->fKeepCredentials, false);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Failed querying \"KeepCredentials\" as a boolean"));
+
+    rc = CFGMR3QueryBoolDef(pCfg, "HeapEnabled", &pThis->fHeapEnabled, true);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Failed querying \"HeapEnabled\" as a boolean"));
+
+    rc = CFGMR3QueryBoolDef(pCfg, "RZEnabled", &pThis->fRZEnabled, true);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Failed querying \"RZEnabled\" as a boolean"));
+
+    rc = CFGMR3QueryBoolDef(pCfg, "GuestCoreDumpEnabled", &pThis->fGuestCoreDumpEnabled, false);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Failed querying \"GuestCoreDumpEnabled\" as a boolean"));
+
+    char *pszGuestCoreDumpDir = NULL;
+    rc = CFGMR3QueryStringAllocDef(pCfg, "GuestCoreDumpDir", &pszGuestCoreDumpDir, "");
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Failed querying \"GuestCoreDumpDir\" as a string"));
+
+    RTStrCopy(pThis->szGuestCoreDumpDir, sizeof(pThis->szGuestCoreDumpDir), pszGuestCoreDumpDir);
+    MMR3HeapFree(pszGuestCoreDumpDir);
+
+    rc = CFGMR3QueryU32Def(pCfg, "GuestCoreDumpCount", &pThis->cGuestCoreDumps, 3);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Failed querying \"GuestCoreDumpCount\" as a 32-bit unsigned integer"));
+
+    rc = CFGMR3QueryU64Def(pCfg, "HeartbeatInterval", &pThis->cNsHeartbeatInterval, VMMDEV_HEARTBEAT_DEFAULT_INTERVAL);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Failed querying \"HeartbeatInterval\" as a 64-bit unsigned integer"));
+    if (pThis->cNsHeartbeatInterval < RT_NS_100MS / 2)
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Heartbeat interval \"HeartbeatInterval\" too small"));
+
+    rc = CFGMR3QueryU64Def(pCfg, "HeartbeatTimeout", &pThis->cNsHeartbeatTimeout, pThis->cNsHeartbeatInterval * 2);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Failed querying \"HeartbeatTimeout\" as a 64-bit unsigned integer"));
+    if (pThis->cNsHeartbeatTimeout < RT_NS_100MS)
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Heartbeat timeout \"HeartbeatTimeout\" too small"));
+    if (pThis->cNsHeartbeatTimeout <= pThis->cNsHeartbeatInterval + RT_NS_10MS)
+        return PDMDevHlpVMSetError(pDevIns, rc, RT_SRC_POS,
+                                   N_("Configuration error: Heartbeat timeout \"HeartbeatTimeout\" value (%'ull ns) is too close to the interval (%'ull ns)"),
+                                   pThis->cNsHeartbeatTimeout, pThis->cNsHeartbeatInterval);
+
+#ifndef VBOX_WITHOUT_TESTING_FEATURES
+    rc = CFGMR3QueryBoolDef(pCfg, "TestingEnabled", &pThis->fTestingEnabled, false);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Failed querying \"TestingEnabled\" as a boolean"));
+    rc = CFGMR3QueryBoolDef(pCfg, "TestingMMIO", &pThis->fTestingMMIO, false);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Failed querying \"TestingMMIO\" as a boolean"));
+    rc = CFGMR3QueryStringAllocDef(pCfg, "TestintXmlOutputFile", &pThis->pszTestingXmlOutput, NULL);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc, N_("Configuration error: Failed querying \"TestintXmlOutputFile\" as a string"));
+
+    /** @todo image-to-load-filename? */
+#endif
+
+    pThis->cbGuestRAM = MMR3PhysGetRamSize(PDMDevHlpGetVM(pDevIns));
+
+    /*
+     * We do our own locking entirely. So, install NOP critsect for the device
+     * and create our own critsect for use where it really matters (++).
+     */
+    rc = PDMDevHlpSetDeviceCritSect(pDevIns, PDMDevHlpCritSectGetNop(pDevIns));
+    AssertRCReturn(rc, rc);
+    rc = PDMDevHlpCritSectInit(pDevIns, &pThis->CritSect, RT_SRC_POS, "VMMDev#%u", iInstance);
+    AssertRCReturn(rc, rc);
+
+    /*
+     * Register the backdoor logging port
+     */
+    rc = PDMDevHlpIOPortRegister(pDevIns, RTLOG_DEBUG_PORT, 1, NULL, vmmdevBackdoorLog,
+                                 NULL, NULL, NULL, "VMMDev backdoor logging");
+    AssertRCReturn(rc, rc);
+
+#ifdef VMMDEV_WITH_ALT_TIMESYNC
+    /*
+     * Alternative timesync source.
+     *
+     * This was orignally added for creating a simple time sync service in an
+     * OpenBSD guest without requiring VBoxGuest and VBoxService to be ported
+     * first.  We keep it in case it comes in handy.
+     */
+    rc = PDMDevHlpIOPortRegister(pDevIns, 0x505, 1, NULL,
+                                 vmmdevAltTimeSyncWrite, vmmdevAltTimeSyncRead,
+                                 NULL, NULL, "VMMDev timesync backdoor");
+    AssertRCReturn(rc, rc);
+#endif
+
+    /*
+     * Register the PCI device.
+     */
+    rc = PDMDevHlpPCIRegister(pDevIns, &pThis->PciDev);
+    if (RT_FAILURE(rc))
+        return rc;
+    if (pThis->PciDev.uDevFn != 32 || iInstance != 0)
+        Log(("!!WARNING!!: pThis->PciDev.uDevFn=%d (ignore if testcase or no started by Main)\n", pThis->PciDev.uDevFn));
+    rc = PDMDevHlpPCIIORegionRegister(pDevIns, 0, 0x20, PCI_ADDRESS_SPACE_IO, vmmdevIOPortRegionMap);
+    if (RT_FAILURE(rc))
+        return rc;
+    rc = PDMDevHlpPCIIORegionRegister(pDevIns, 1, VMMDEV_RAM_SIZE, PCI_ADDRESS_SPACE_MEM, vmmdevIORAMRegionMap);
+    if (RT_FAILURE(rc))
+        return rc;
+    if (pThis->fHeapEnabled)
+    {
+        rc = PDMDevHlpPCIIORegionRegister(pDevIns, 2, VMMDEV_HEAP_SIZE, PCI_ADDRESS_SPACE_MEM_PREFETCH, vmmdevIORAMRegionMap);
+        if (RT_FAILURE(rc))
+            return rc;
+    }
+
+    /*
+     * Allocate and initialize the MMIO2 memory.
+     *
+     * We map the first page into raw-mode and kernel contexts so we can handle
+     * interrupt acknowledge requests more timely.
+     */
+    rc = PDMDevHlpMMIO2Register(pDevIns, &pThis->PciDev, 1 /*iRegion*/, VMMDEV_RAM_SIZE, 0 /*fFlags*/,
+                                (void **)&pThis->pVMMDevRAMR3, "VMMDev");
+    if (RT_FAILURE(rc))
+        return PDMDevHlpVMSetError(pDevIns, rc, RT_SRC_POS,
+                                   N_("Failed to allocate %u bytes of memory for the VMM device"), VMMDEV_RAM_SIZE);
+    vmmdevInitRam(pThis);
+    if (pThis->fRZEnabled)
+    {
+        rc = PDMDevHlpMMIO2MapKernel(pDevIns, &pThis->PciDev, 1 /*iRegion*/, 0 /*off*/, PAGE_SIZE, "VMMDev", &pThis->pVMMDevRAMR0);
+        if (RT_FAILURE(rc))
+            return PDMDevHlpVMSetError(pDevIns, rc, RT_SRC_POS,
+                                       N_("Failed to map first page of the VMMDev ram into kernel space: %Rrc"), rc);
+
+#ifdef VBOX_WITH_RAW_MODE
+        rc = PDMDevHlpMMHyperMapMMIO2(pDevIns, &pThis->PciDev, 1 /*iRegion*/, 0 /*off*/, PAGE_SIZE, "VMMDev", &pThis->pVMMDevRAMRC);
+        if (RT_FAILURE(rc))
+            return PDMDevHlpVMSetError(pDevIns, rc, RT_SRC_POS,
+                                       N_("Failed to map first page of the VMMDev ram into raw-mode context: %Rrc"), rc);
+#endif
+    }
+
+    /*
+     * Allocate and initialize the MMIO2 heap.
+     */
+    if (pThis->fHeapEnabled)
+    {
+        rc = PDMDevHlpMMIO2Register(pDevIns, &pThis->PciDev, 2 /*iRegion*/, VMMDEV_HEAP_SIZE, 0 /*fFlags*/,
+                                    (void **)&pThis->pVMMDevHeapR3, "VMMDev Heap");
+        if (RT_FAILURE(rc))
+            return PDMDevHlpVMSetError(pDevIns, rc, RT_SRC_POS,
+                                       N_("Failed to allocate %u bytes of memory for the VMM device heap"), PAGE_SIZE);
+
+        /* Register the memory area with PDM so HM can access it before it's mapped. */
+        rc = PDMDevHlpRegisterVMMDevHeap(pDevIns, NIL_RTGCPHYS, pThis->pVMMDevHeapR3, VMMDEV_HEAP_SIZE);
+        AssertLogRelRCReturn(rc, rc);
+    }
+
+#ifndef VBOX_WITHOUT_TESTING_FEATURES
+    /*
+     * Initialize testing.
+     */
+    rc = vmmdevTestingInitialize(pDevIns);
+    if (RT_FAILURE(rc))
+        return rc;
+#endif
+
+    /*
+     * Get the corresponding connector interface
+     */
+    rc = PDMDevHlpDriverAttach(pDevIns, 0, &pThis->IBase, &pThis->pDrvBase, "VMM Driver Port");
+    if (RT_SUCCESS(rc))
+    {
+        pThis->pDrv = PDMIBASE_QUERY_INTERFACE(pThis->pDrvBase, PDMIVMMDEVCONNECTOR);
+        AssertMsgReturn(pThis->pDrv, ("LUN #0 doesn't have a VMMDev connector interface!\n"), VERR_PDM_MISSING_INTERFACE);
+#ifdef VBOX_WITH_HGCM
+        pThis->pHGCMDrv = PDMIBASE_QUERY_INTERFACE(pThis->pDrvBase, PDMIHGCMCONNECTOR);
+        if (!pThis->pHGCMDrv)
+        {
+            Log(("LUN #0 doesn't have a HGCM connector interface, HGCM is not supported. rc=%Rrc\n", rc));
+            /* this is not actually an error, just means that there is no support for HGCM */
+        }
+#endif
+        /* Query the initial balloon size. */
+        AssertPtr(pThis->pDrv->pfnQueryBalloonSize);
+        rc = pThis->pDrv->pfnQueryBalloonSize(pThis->pDrv, &pThis->cMbMemoryBalloon);
+        AssertRC(rc);
+
+        Log(("Initial balloon size %x\n", pThis->cMbMemoryBalloon));
+    }
+    else if (rc == VERR_PDM_NO_ATTACHED_DRIVER)
+    {
+        Log(("%s/%d: warning: no driver attached to LUN #0!\n", pDevIns->pReg->szName, pDevIns->iInstance));
+        rc = VINF_SUCCESS;
+    }
+    else
+        AssertMsgFailedReturn(("Failed to attach LUN #0! rc=%Rrc\n", rc), rc);
+
+    /*
+     * Attach status driver for shared folders (optional).
+     */
+    PPDMIBASE pBase;
+    rc = PDMDevHlpDriverAttach(pDevIns, PDM_STATUS_LUN, &pThis->IBase, &pBase, "Status Port");
+    if (RT_SUCCESS(rc))
+        pThis->SharedFolders.pLedsConnector = PDMIBASE_QUERY_INTERFACE(pBase, PDMILEDCONNECTORS);
+    else if (rc != VERR_PDM_NO_ATTACHED_DRIVER)
+    {
+        AssertMsgFailed(("Failed to attach to status driver. rc=%Rrc\n", rc));
+        return rc;
+    }
+
+    /*
+     * Register saved state and init the HGCM CmdList critsect.
+     */
+    rc = PDMDevHlpSSMRegisterEx(pDevIns, VMMDEV_SAVED_STATE_VERSION, sizeof(*pThis), NULL,
+                                NULL, vmmdevLiveExec, NULL,
+                                NULL, vmmdevSaveExec, NULL,
+                                NULL, vmmdevLoadExec, vmmdevLoadStateDone);
+    AssertRCReturn(rc, rc);
+
+    /*
+     * Create heartbeat checking timer.
+     */
+    rc = PDMDevHlpTMTimerCreate(pDevIns, TMCLOCK_VIRTUAL, vmmDevHeartbeatFlatlinedTimer, pThis,
+                                TMTIMER_FLAGS_NO_CRIT_SECT, "Heartbeat flatlined", &pThis->pFlatlinedTimer);
+    AssertRCReturn(rc, rc);
+
+#ifdef VBOX_WITH_HGCM
+    rc = vmmdevHGCMInit(pThis);
+    AssertRCReturn(rc, rc);
+#endif
+
+    /*
+     * In this version of VirtualBox the GUI checks whether "needs host cursor"
+     * changes.
+     */
+    pThis->mouseCapabilities |= VMMDEV_MOUSE_HOST_RECHECKS_NEEDS_HOST_CURSOR;
+
+    /*
+     * Statistics.
+     */
+    PDMDevHlpSTAMRegisterF(pDevIns, &pThis->StatMemBalloonChunks, STAMTYPE_U32, STAMVISIBILITY_ALWAYS, STAMUNIT_COUNT,
+                           "Memory balloon size",                           "/Devices/VMMDev/BalloonChunks");
+    PDMDevHlpSTAMRegisterF(pDevIns, &pThis->StatFastIrqAckR3,      STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, STAMUNIT_COUNT,
+                           "Fast IRQ acknowledgments handled in ring-3.",   "/Devices/VMMDev/FastIrqAckR3");
+    PDMDevHlpSTAMRegisterF(pDevIns, &pThis->StatFastIrqAckRZ,      STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, STAMUNIT_COUNT,
+                           "Fast IRQ acknowledgments handled in ring-0 or raw-mode.", "/Devices/VMMDev/FastIrqAckRZ");
+    PDMDevHlpSTAMRegisterF(pDevIns, &pThis->StatSlowIrqAck,        STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, STAMUNIT_COUNT,
+                           "Slow IRQ acknowledgments (old style).",         "/Devices/VMMDev/SlowIrqAck");
+    PDMDevHlpSTAMRegisterF(pDevIns, &pThis->StatReqBufAllocs,      STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, STAMUNIT_COUNT,
+                           "Times a larger request buffer was required.",   "/Devices/VMMDev/LargeReqBufAllocs");
+#ifdef VBOX_WITH_HGCM
+    PDMDevHlpSTAMRegisterF(pDevIns, &pThis->StatHgcmCmdArrival,    STAMTYPE_PROFILE, STAMVISIBILITY_ALWAYS, STAMUNIT_TICKS_PER_CALL,
+                           "Profiling HGCM call arrival processing",        "/HGCM/MsgArrival");
+    PDMDevHlpSTAMRegisterF(pDevIns, &pThis->StatHgcmCmdCompletion, STAMTYPE_PROFILE, STAMVISIBILITY_ALWAYS, STAMUNIT_TICKS_PER_CALL,
+                           "Profiling HGCM call completion processing",     "/HGCM/MsgCompletion");
+    PDMDevHlpSTAMRegisterF(pDevIns, &pThis->StatHgcmCmdTotal,      STAMTYPE_PROFILE, STAMVISIBILITY_ALWAYS, STAMUNIT_TICKS_PER_CALL,
+                           "Profiling whole HGCM call.",                    "/HGCM/MsgTotal");
+    PDMDevHlpSTAMRegisterF(pDevIns, &pThis->StatHgcmLargeCmdAllocs,STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, STAMUNIT_COUNT,
+                           "Times the allocation cache could not be used.", "/HGCM/LargeCmdAllocs");
+#endif
+
+    /*
+     * Generate a unique session id for this VM; it will be changed for each
+     * start, reset or restore. This can be used for restore detection inside
+     * the guest.
+     */
+    pThis->idSession = ASMReadTSC();
+    return rc;
+}
+
+/**
+ * The device registration structure.
+ */
+extern "C" const PDMDEVREG g_DeviceVMMDev =
+{
+    /* u32Version */
+    PDM_DEVREG_VERSION,
+    /* szName */
+    "VMMDev",
+    /* szRCMod */
+    "VBoxDDRC.rc",
+    /* szR0Mod */
+    "VBoxDDR0.r0",
+    /* pszDescription */
+    "VirtualBox VMM Device\n",
+    /* fFlags */
+    PDM_DEVREG_FLAGS_HOST_BITS_DEFAULT | PDM_DEVREG_FLAGS_GUEST_BITS_DEFAULT | PDM_DEVREG_FLAGS_RC | PDM_DEVREG_FLAGS_R0,
+    /* fClass */
+    PDM_DEVREG_CLASS_VMM_DEV,
+    /* cMaxInstances */
+    1,
+    /* cbInstance */
+    sizeof(VMMDevState),
+    /* pfnConstruct */
+    vmmdevConstruct,
+    /* pfnDestruct */
+    vmmdevDestruct,
+    /* pfnRelocate */
+    vmmdevRelocate,
+    /* pfnMemSetup */
+    NULL,
+    /* pfnPowerOn */
+    NULL,
+    /* pfnReset */
+    vmmdevReset,
+    /* pfnSuspend */
+    NULL,
+    /* pfnResume */
+    NULL,
+    /* pfnAttach */
+    NULL,
+    /* pfnDetach */
+    NULL,
+    /* pfnQueryInterface. */
+    NULL,
+    /* pfnInitComplete */
+    NULL,
+    /* pfnPowerOff */
+    NULL,
+    /* pfnSoftReset */
+    NULL,
+    /* u32VersionEnd */
+    PDM_DEVREG_VERSION
+};
+#endif /* IN_RING3 */
+#endif /* !VBOX_DEVICE_STRUCT_TESTCASE */