Adding upstream version 7.0.6-dfsg.upstream/7.0.6-dfsgupstream

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

1 files changed, 1933 insertions, 0 deletions

diff --git a/src/VBox/Devices/PC/DevPcBios.cpp b/src/VBox/Devices/PC/DevPcBios.cpp
new file mode 100644
index 00000000..fab38b3a
--- /dev/null
+++ b/src/VBox/Devices/PC/DevPcBios.cpp
@@ -0,0 +1,1933 @@
+/* $Id: DevPcBios.cpp $ */
+/** @file
+ * DevPcBios - PC BIOS Device.
+ */
+
+/*
+ * Copyright (C) 2006-2022 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP LOG_GROUP_DEV_PC_BIOS
+#include <VBox/vmm/pdmdev.h>
+#include <VBox/vmm/pdmstorageifs.h>
+#include <VBox/vmm/mm.h>
+#include <VBox/vmm/pgm.h>
+#include <VBox/vmm/cpum.h>
+
+#include <VBox/log.h>
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/buildconfig.h>
+#include <iprt/file.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/uuid.h>
+#include <iprt/cdefs.h>
+#include <VBox/bios.h>
+#include <VBox/err.h>
+#include <VBox/param.h>
+
+#include "VBoxDD.h"
+#include "VBoxDD2.h"
+#include "DevPcBios.h"
+#include "DevFwCommon.h"
+
+#define NET_BOOT_DEVS   4
+
+
+/** @page pg_devbios_cmos_assign    CMOS Assignments (BIOS)
+ *
+ * The BIOS uses a CMOS to store configuration data.
+ * It is currently used as follows:
+ *
+ * @verbatim
+  First CMOS bank (offsets 0x00 to 0x7f):
+    Floppy drive type:
+         0x10
+    Hard disk type (old):
+         0x12
+    Equipment byte:
+         0x14
+    Base memory:
+         0x15
+         0x16
+    Extended memory:
+         0x17
+         0x18
+         0x30
+         0x31
+    First IDE HDD:
+         0x19
+         0x1e - 0x25
+    Second IDE HDD:
+         0x1a
+         0x26 - 0x2d
+    Checksum of 0x10-0x2d:
+         0x2e
+         0x2f
+    Amount of memory above 16M and below 4GB in 64KB units:
+         0x34
+         0x35
+    Boot device (BOCHS BIOS specific):
+         0x38
+         0x3c
+         0x3d
+    PXE debug:
+         0x3f
+    First SATA HDD:
+         0x40 - 0x47
+    Second SATA HDD:
+         0x48 - 0x4f
+    Third SATA HDD:
+         0x50 - 0x57
+    Fourth SATA HDD:
+         0x58 - 0x5f
+    Number of CPUs:
+         0x60
+    RAM above 4G in 64KB units:
+         0x61 - 0x65
+    Third IDE HDD:
+         0x67 - 0x6e
+    Fourth IDE HDD:
+         0x70 - 0x77
+    APIC/x2APIC settings:
+         0x78
+
+  Second CMOS bank (offsets 0x80 to 0xff):
+    Reserved for internal use by PXE ROM:
+         0x80 - 0x81
+    First net boot device PCI bus/dev/fn:
+         0x82 - 0x83
+    Second to third net boot devices:
+         0x84 - 0x89
+    First SCSI HDD:
+         0x90 - 0x97
+    Second SCSI HDD:
+         0x98 - 0x9f
+    Third SCSI HDD:
+         0xa0 - 0xa7
+    Fourth SCSI HDD:
+         0xa8 - 0xaf
+
+@endverbatim
+ *
+ * @todo Mark which bits are compatible with which BIOSes and
+ *       which are our own definitions.
+ */
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/**
+ * The boot device.
+ */
+typedef enum DEVPCBIOSBOOT
+{
+    DEVPCBIOSBOOT_NONE,
+    DEVPCBIOSBOOT_FLOPPY,
+    DEVPCBIOSBOOT_HD,
+    DEVPCBIOSBOOT_DVD,
+    DEVPCBIOSBOOT_LAN
+} DEVPCBIOSBOOT;
+
+/**
+ * PC Bios instance data structure.
+ */
+typedef struct DEVPCBIOS
+{
+    /** Pointer back to the device instance. */
+    PPDMDEVINS      pDevIns;
+
+    /** Boot devices (ordered). */
+    DEVPCBIOSBOOT   aenmBootDevice[4];
+    /** Bochs control string index. */
+    uint32_t        iControl;
+    /** Floppy device. */
+    char           *pszFDDevice;
+    /** Harddisk device. */
+    char           *pszHDDevice;
+    /** Sata harddisk device. */
+    char           *pszSataDevice;
+    /** LUNs of the four BIOS-accessible SATA disks. */
+    uint32_t        iSataHDLUN[4];
+    /** SCSI harddisk device. */
+    char           *pszScsiDevice;
+    /** LUNs of the four BIOS-accessible SCSI disks. */
+    uint32_t        iScsiHDLUN[4];
+    /** Bios message buffer. */
+    char            szMsg[256];
+    /** Bios message buffer index. */
+    uint32_t        iMsg;
+    /** The system BIOS ROM data. */
+    uint8_t        *pu8PcBios;
+    /** The size of the system BIOS ROM. */
+    uint32_t        cbPcBios;
+    /** The name of the BIOS ROM file. */
+    char           *pszPcBiosFile;
+    /** The LAN boot ROM data. */
+    uint8_t        *pu8LanBoot;
+    /** The name of the LAN boot ROM file. */
+    char           *pszLanBootFile;
+    /** The size of the LAN boot ROM. */
+    uint64_t        cbLanBoot;
+    /** The DMI tables. */
+    uint8_t         au8DMIPage[0x1000];
+    /** The boot countdown (in seconds). */
+    uint8_t         uBootDelay;
+    /** I/O-APIC enabled? */
+    uint8_t         u8IOAPIC;
+    /** APIC mode to be set up by BIOS */
+    uint8_t         u8APICMode;
+    /** PXE debug logging enabled? */
+    uint8_t         u8PXEDebug;
+    /** Physical address of the MP table. */
+    uint32_t        u32MPTableAddr;
+    /** PXE boot PCI bus/dev/fn list. */
+    uint16_t        au16NetBootDev[NET_BOOT_DEVS];
+    /** Number of logical CPUs in guest */
+    uint16_t        cCpus;
+    /* Physical address of PCI config space MMIO region. Currently unused. */
+    uint64_t        u64McfgBase;
+    /* Length of PCI config space MMIO region. Currently unused. */
+    uint64_t        cbMcfgLength;
+
+    /** Firmware registration structure.   */
+    PDMFWREG        FwReg;
+    /** Dummy. */
+    PCPDMFWHLPR3    pFwHlpR3;
+    /** Number of soft resets we've logged. */
+    uint32_t        cLoggedSoftResets;
+    /** Whether to consult the shutdown status (CMOS[0xf]) for deciding upon soft
+     * or hard reset. */
+    bool            fCheckShutdownStatusForSoftReset;
+    /** Whether to clear the shutdown status on hard reset. */
+    bool            fClearShutdownStatusOnHardReset;
+    /** Current port number for Bochs shutdown (used by APM). */
+    RTIOPORT        ShutdownPort;
+    /** True=use new port number for Bochs shutdown (used by APM). */
+    bool            fNewShutdownPort;
+    bool            afPadding[3+4];
+    /** The shudown I/O port, either at 0x040f or 0x8900 (old saved state). */
+    IOMMMIOHANDLE   hIoPortShutdown;
+} DEVPCBIOS;
+/** Pointer to the BIOS device state. */
+typedef DEVPCBIOS *PDEVPCBIOS;
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** The saved state version. */
+#define PCBIOS_SSM_VERSION 0
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Saved state DEVPCBIOS field descriptors. */
+static SSMFIELD const g_aPcBiosFields[] =
+{
+    SSMFIELD_ENTRY(         DEVPCBIOS, fNewShutdownPort),
+    SSMFIELD_ENTRY_TERM()
+};
+
+
+/**
+ * @callback_method_impl{FNIOMIOPORTNEWIN, Bochs Debug.}
+ */
+static DECLCALLBACK(VBOXSTRICTRC)
+pcbiosIOPortDebugRead(PPDMDEVINS pDevIns, void *pvUser, RTIOPORT offPort, uint32_t *pu32, unsigned cb)
+{
+    RT_NOREF5(pDevIns, pvUser, offPort, pu32, cb);
+    return VERR_IOM_IOPORT_UNUSED;
+}
+
+
+/**
+ * @callback_method_impl{FNIOMIOPORTNEWOUT, Bochs Debug.}
+ */
+static DECLCALLBACK(VBOXSTRICTRC)
+pcbiosIOPortDebugWrite(PPDMDEVINS pDevIns, void *pvUser, RTIOPORT offPort, uint32_t u32, unsigned cb)
+{
+    PDEVPCBIOS pThis = PDMDEVINS_2_DATA(pDevIns, PDEVPCBIOS);
+    RT_NOREF(pvUser);
+    Assert(offPort < 4);
+
+    /*
+     * Bochs BIOS char printing.
+     */
+    if (    cb == 1
+        &&  (   offPort == 2
+             || offPort == 3))
+    {
+        /* The raw version. */
+        switch (u32)
+        {
+            case '\r': Log2(("pcbios: <return>\n")); break;
+            case '\n': Log2(("pcbios: <newline>\n")); break;
+            case '\t': Log2(("pcbios: <tab>\n")); break;
+            default:   Log2(("pcbios: %c (%02x)\n", u32, u32)); break;
+        }
+
+        /* The readable, buffered version. */
+        uint32_t iMsg = pThis->iMsg;
+        if (u32 == '\n' || u32 == '\r')
+        {
+            AssertStmt(iMsg < sizeof(pThis->szMsg), iMsg = sizeof(pThis->szMsg) - 1);
+            pThis->szMsg[iMsg] = '\0';
+            if (iMsg)
+                Log(("pcbios: %s\n", pThis->szMsg));
+            iMsg = 0;
+        }
+        else
+        {
+            if (iMsg >= sizeof(pThis->szMsg) - 1)
+            {
+                pThis->szMsg[iMsg] = '\0';
+                Log(("pcbios: %s\n", pThis->szMsg));
+                iMsg = 0;
+            }
+            pThis->szMsg[iMsg] = (char)u32;
+            pThis->szMsg[++iMsg] = '\0';
+        }
+        pThis->iMsg = iMsg;
+        return VINF_SUCCESS;
+    }
+
+    /* not in use. */
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * @callback_method_impl{FNIOMIOPORTNEWIN, Bochs Shutdown port.}
+ */
+static DECLCALLBACK(VBOXSTRICTRC)
+pcbiosIOPortShutdownRead(PPDMDEVINS pDevIns, void *pvUser, RTIOPORT offPort, uint32_t *pu32, unsigned cb)
+{
+    RT_NOREF5(pDevIns, pvUser, offPort, pu32, cb);
+    return VERR_IOM_IOPORT_UNUSED;
+}
+
+
+/**
+ * @callback_method_impl{FNIOMIOPORTNEWOUT, Bochs Shutdown port.}
+ */
+static DECLCALLBACK(VBOXSTRICTRC)
+pcbiosIOPortShutdownWrite(PPDMDEVINS pDevIns, void *pvUser, RTIOPORT offPort, uint32_t u32, unsigned cb)
+{
+    PDEVPCBIOS pThis = PDMDEVINS_2_DATA(pDevIns, PDEVPCBIOS);
+    RT_NOREF(pvUser, offPort);
+    Assert(offPort == 0);
+
+    if (cb == 1)
+    {
+        static const unsigned char s_szShutdown[] = "Shutdown";
+        static const unsigned char s_szBootfail[] = "Bootfail";
+        AssertCompile(sizeof(s_szShutdown) == sizeof(s_szBootfail));
+
+        if (pThis->iControl < sizeof(s_szShutdown)) /* paranoia */
+        {
+            if (u32 == s_szShutdown[pThis->iControl])
+            {
+
+                pThis->iControl++;
+                if (pThis->iControl >= 8)
+                {
+                    pThis->iControl = 0;
+                    LogRel(("PcBios: APM shutdown request\n"));
+                    return PDMDevHlpVMPowerOff(pDevIns);
+                }
+            }
+            else if (u32 == s_szBootfail[pThis->iControl])
+            {
+                pThis->iControl++;
+                if (pThis->iControl >= 8)
+                {
+                    pThis->iControl = 0;
+                    LogRel(("PcBios: Boot failure\n"));
+                    int rc = PDMDevHlpVMSetRuntimeError(pDevIns, 0 /*fFlags*/, "VMBootFail",
+                                                        N_("The VM failed to boot. This is possibly caused by not having an operating system installed or a misconfigured boot order. Maybe picking a guest OS install DVD will resolve the situation"));
+                    AssertRC(rc);
+                }
+            }
+            else
+                pThis->iControl = 0;
+        }
+        else
+            pThis->iControl = 0;
+    }
+    /* else: not in use. */
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Register the Bochs shutdown port.
+ * This is used by pcbiosConstruct, pcbiosReset and pcbiosLoadExec.
+ */
+static int pcbiosRegisterShutdown(PPDMDEVINS pDevIns, PDEVPCBIOS pThis, bool fNewShutdownPort)
+{
+    if (pThis->ShutdownPort != 0)
+    {
+        int rc = PDMDevHlpIoPortUnmap(pDevIns, pThis->hIoPortShutdown);
+        AssertRC(rc);
+    }
+
+    pThis->fNewShutdownPort = fNewShutdownPort;
+    if (fNewShutdownPort)
+        pThis->ShutdownPort = VBOX_BIOS_SHUTDOWN_PORT;
+    else
+        pThis->ShutdownPort = VBOX_BIOS_OLD_SHUTDOWN_PORT;
+    return PDMDevHlpIoPortMap(pDevIns, pThis->hIoPortShutdown, pThis->ShutdownPort);
+}
+
+
+/**
+ * @callback_method_impl{FNSSMDEVSAVEEXEC}
+ */
+static DECLCALLBACK(int) pcbiosSaveExec(PPDMDEVINS pDevIns, PSSMHANDLE pSSM)
+{
+    PDEVPCBIOS pThis = PDMDEVINS_2_DATA(pDevIns, PDEVPCBIOS);
+    return pDevIns->pHlpR3->pfnSSMPutStruct(pSSM, pThis, g_aPcBiosFields);
+}
+
+
+/**
+ * @callback_method_impl{FNSSMDEVLOADPREP,
+ *      Clears the fNewShutdownPort flag prior to loading the state so that old
+ *      saved VM states keeps using the old port address (no pcbios state)}
+ */
+static DECLCALLBACK(int) pcbiosLoadPrep(PPDMDEVINS pDevIns, PSSMHANDLE pSSM)
+{
+    RT_NOREF(pSSM);
+    PDEVPCBIOS pThis = PDMDEVINS_2_DATA(pDevIns, PDEVPCBIOS);
+
+    /* Since there are legacy saved state files without any SSM data for PCBIOS
+     * this is the only way to handle them correctly. */
+    pThis->fNewShutdownPort = false;
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * @callback_method_impl{FNSSMDEVLOADEXEC}
+ */
+static DECLCALLBACK(int) pcbiosLoadExec(PPDMDEVINS pDevIns, PSSMHANDLE pSSM, uint32_t uVersion, uint32_t uPass)
+{
+    PDEVPCBIOS pThis = PDMDEVINS_2_DATA(pDevIns, PDEVPCBIOS);
+
+    if (uVersion > PCBIOS_SSM_VERSION)
+        return VERR_SSM_UNSUPPORTED_DATA_UNIT_VERSION;
+    Assert(uPass == SSM_PASS_FINAL); NOREF(uPass);
+
+    return pDevIns->pHlpR3->pfnSSMGetStruct(pSSM, pThis, g_aPcBiosFields);
+}
+
+
+/**
+ * @callback_method_impl{FNSSMDEVLOADDONE,
+ *      Updates the shutdown port registration to match the flag loaded (or not).}
+ */
+static DECLCALLBACK(int) pcbiosLoadDone(PPDMDEVINS pDevIns, PSSMHANDLE pSSM)
+{
+    RT_NOREF(pSSM);
+    PDEVPCBIOS pThis = PDMDEVINS_2_DATA(pDevIns, PDEVPCBIOS);
+    return pcbiosRegisterShutdown(pDevIns, pThis, pThis->fNewShutdownPort);
+}
+
+
+/**
+ * Write to CMOS memory.
+ * This is used by the init complete code.
+ */
+static void pcbiosCmosWrite(PPDMDEVINS pDevIns, int off, uint32_t u32Val)
+{
+    Assert(off < 256);
+    Assert(u32Val < 256);
+
+    int rc = PDMDevHlpCMOSWrite(pDevIns, off, u32Val);
+    AssertRC(rc);
+}
+
+
+/**
+ * Read from CMOS memory.
+ * This is used by the init complete code.
+ */
+static uint8_t pcbiosCmosRead(PPDMDEVINS pDevIns, unsigned off)
+{
+    Assert(off < 256);
+
+    uint8_t u8val;
+    int rc = PDMDevHlpCMOSRead(pDevIns, off, &u8val);
+    AssertRC(rc);
+
+    return u8val;
+}
+
+
+/**
+ * @interface_method_impl{PDMFWREG,pfnIsHardReset}
+ */
+static DECLCALLBACK(bool) pcbiosFw_IsHardReset(PPDMDEVINS pDevIns, uint32_t fFlags)
+{
+    RT_NOREF1(fFlags);
+    PDEVPCBIOS pThis = PDMDEVINS_2_DATA(pDevIns, PDEVPCBIOS);
+    if (pThis->fCheckShutdownStatusForSoftReset)
+    {
+        uint8_t bShutdownStatus = pcbiosCmosRead(pDevIns, 0xf);
+        if (   bShutdownStatus == 0x5
+            || bShutdownStatus == 0x9
+            || bShutdownStatus == 0xa)
+        {
+            const uint32_t cMaxLogged = 10;
+            if (pThis->cLoggedSoftResets < cMaxLogged)
+            {
+                RTFAR16 Far16 = { 0xfeed, 0xface };
+                PDMDevHlpPhysRead(pDevIns, 0x467, &Far16, sizeof(Far16));
+                pThis->cLoggedSoftResets++;
+                LogRel(("PcBios: Soft reset #%u - shutdown status %#x, warm reset vector (0040:0067) is %04x:%04x%s\n",
+                        pThis->cLoggedSoftResets, bShutdownStatus, Far16.sel, Far16.off,
+                        pThis->cLoggedSoftResets < cMaxLogged ? "." : " - won't log any more!"));
+            }
+            return false;
+        }
+    }
+    return true;
+}
+
+
+/**
+ * @interface_method_impl{PDMDEVREG,pfnReset}
+ */
+static DECLCALLBACK(void) pcbiosReset(PPDMDEVINS pDevIns)
+{
+    PDEVPCBIOS pThis = PDMDEVINS_2_DATA(pDevIns, PDEVPCBIOS);
+
+    if (pThis->fClearShutdownStatusOnHardReset)
+    {
+        uint8_t bShutdownStatus = pcbiosCmosRead(pDevIns, 0xf);
+        if (bShutdownStatus != 0)
+        {
+            LogRel(("PcBios: Clearing shutdown status code %02x.\n", bShutdownStatus));
+            pcbiosCmosWrite(pDevIns, 0xf, 0);
+        }
+    }
+
+    /* After reset the new BIOS code is active, use the new shutdown port. */
+    pcbiosRegisterShutdown(pDevIns, pThis, true /* fNewShutdownPort */);
+}
+
+
+/**
+ * Attempt to guess the LCHS disk geometry from the MS-DOS master boot record
+ * (partition table).
+ *
+ * @returns VBox status code.
+ * @param   pMedia          The media device interface of the disk.
+ * @param   pLCHSGeometry   Where to return the disk geometry on success
+ */
+static int biosGuessDiskLCHS(PPDMIMEDIA pMedia, PPDMMEDIAGEOMETRY pLCHSGeometry)
+{
+    uint8_t aMBR[512], *p;
+    int rc;
+    uint32_t iEndHead, iEndSector, cLCHSCylinders, cLCHSHeads, cLCHSSectors;
+
+    if (!pMedia)
+        return VERR_INVALID_PARAMETER;
+    rc = pMedia->pfnReadPcBios(pMedia, 0, aMBR, sizeof(aMBR));
+    if (RT_FAILURE(rc))
+        return rc;
+    /* Test MBR magic number. */
+    if (aMBR[510] != 0x55 || aMBR[511] != 0xaa)
+        return VERR_INVALID_PARAMETER;
+    for (uint32_t i = 0; i < 4; i++)
+    {
+        /* Figure out the start of a partition table entry. */
+        p = &aMBR[0x1be + i * 16];
+        iEndHead = p[5];
+        iEndSector = p[6] & 63;
+        if ((p[12] | p[13] | p[14] | p[15]) && iEndSector && iEndHead)
+        {
+            /* Assumption: partition terminates on a cylinder boundary. */
+            cLCHSHeads = iEndHead + 1;
+            cLCHSSectors = iEndSector;
+            cLCHSCylinders = RT_MIN(1024, pMedia->pfnGetSize(pMedia) / (512 * cLCHSHeads * cLCHSSectors));
+            if (cLCHSCylinders >= 1)
+            {
+                pLCHSGeometry->cCylinders = cLCHSCylinders;
+                pLCHSGeometry->cHeads = cLCHSHeads;
+                pLCHSGeometry->cSectors = cLCHSSectors;
+                Log(("%s: LCHS=%d %d %d\n", __FUNCTION__, cLCHSCylinders, cLCHSHeads, cLCHSSectors));
+                return VINF_SUCCESS;
+            }
+        }
+    }
+    return VERR_INVALID_PARAMETER;
+}
+
+
+/**
+ * Initializes the CMOS data for one harddisk.
+ */
+static void pcbiosCmosInitHardDisk(PPDMDEVINS pDevIns, int offType, int offInfo, PCPDMMEDIAGEOMETRY pLCHSGeometry)
+{
+    Log2(("%s: offInfo=%#x: LCHS=%d/%d/%d\n", __FUNCTION__, offInfo, pLCHSGeometry->cCylinders, pLCHSGeometry->cHeads, pLCHSGeometry->cSectors));
+    if (offType)
+        pcbiosCmosWrite(pDevIns, offType, 47);
+    /* Cylinders low */
+    pcbiosCmosWrite(pDevIns, offInfo + 0, RT_MIN(pLCHSGeometry->cCylinders, 1024) & 0xff);
+    /* Cylinders high */
+    pcbiosCmosWrite(pDevIns, offInfo + 1, RT_MIN(pLCHSGeometry->cCylinders, 1024) >> 8);
+    /* Heads */
+    pcbiosCmosWrite(pDevIns, offInfo + 2, pLCHSGeometry->cHeads);
+    /* Landing zone low */
+    pcbiosCmosWrite(pDevIns, offInfo + 3, 0xff);
+    /* Landing zone high */
+    pcbiosCmosWrite(pDevIns, offInfo + 4, 0xff);
+    /* Write precomp low */
+    pcbiosCmosWrite(pDevIns, offInfo + 5, 0xff);
+    /* Write precomp high */
+    pcbiosCmosWrite(pDevIns, offInfo + 6, 0xff);
+    /* Sectors */
+    pcbiosCmosWrite(pDevIns, offInfo + 7, pLCHSGeometry->cSectors);
+}
+
+
+/**
+ * Set logical CHS geometry for a hard disk
+ *
+ * @returns VBox status code.
+ * @param   pBase         Base interface for the device.
+ * @param   pHardDisk     The hard disk.
+ * @param   pLCHSGeometry Where to store the geometry settings.
+ */
+static int setLogicalDiskGeometry(PPDMIBASE pBase, PPDMIMEDIA pHardDisk, PPDMMEDIAGEOMETRY pLCHSGeometry)
+{
+    RT_NOREF1(pBase);
+
+    PDMMEDIAGEOMETRY LCHSGeometry;
+    int rc = pHardDisk->pfnBiosGetLCHSGeometry(pHardDisk, &LCHSGeometry);
+    if (   rc == VERR_PDM_GEOMETRY_NOT_SET
+        || LCHSGeometry.cCylinders == 0
+        || LCHSGeometry.cHeads == 0
+        || LCHSGeometry.cHeads > 255
+        || LCHSGeometry.cSectors == 0
+        || LCHSGeometry.cSectors > 63)
+    {
+        /* No LCHS geometry, autodetect and set. */
+        rc = biosGuessDiskLCHS(pHardDisk, &LCHSGeometry);
+        if (RT_FAILURE(rc))
+        {
+            /* Try if PCHS geometry works, otherwise fall back. */
+            rc = pHardDisk->pfnBiosGetPCHSGeometry(pHardDisk, &LCHSGeometry);
+        }
+        if (   RT_FAILURE(rc)
+            || LCHSGeometry.cCylinders == 0
+            || LCHSGeometry.cCylinders > 1024
+            || LCHSGeometry.cHeads == 0
+            || LCHSGeometry.cHeads > 255
+            || LCHSGeometry.cSectors == 0
+            || LCHSGeometry.cSectors > 63)
+        {
+            uint64_t cSectors = pHardDisk->pfnGetSize(pHardDisk) / 512;
+            if (cSectors / 16 / 63 <= 1024)
+            {
+                LCHSGeometry.cCylinders = RT_MAX(cSectors / 16 / 63, 1);
+                LCHSGeometry.cHeads = 16;
+            }
+            else if (cSectors / 32 / 63 <= 1024)
+            {
+                LCHSGeometry.cCylinders = RT_MAX(cSectors / 32 / 63, 1);
+                LCHSGeometry.cHeads = 32;
+            }
+            else if (cSectors / 64 / 63 <= 1024)
+            {
+                LCHSGeometry.cCylinders = cSectors / 64 / 63;
+                LCHSGeometry.cHeads = 64;
+            }
+            else if (cSectors / 128 / 63 <= 1024)
+            {
+                LCHSGeometry.cCylinders = cSectors / 128 / 63;
+                LCHSGeometry.cHeads = 128;
+            }
+            else
+            {
+                LCHSGeometry.cCylinders = RT_MIN(cSectors / 255 / 63, 1024);
+                LCHSGeometry.cHeads = 255;
+            }
+            LCHSGeometry.cSectors = 63;
+
+        }
+        rc = pHardDisk->pfnBiosSetLCHSGeometry(pHardDisk, &LCHSGeometry);
+        if (rc == VERR_VD_IMAGE_READ_ONLY)
+        {
+            LogRel(("PcBios: ATA failed to update LCHS geometry, read only\n"));
+            rc = VINF_SUCCESS;
+        }
+        else if (rc == VERR_PDM_GEOMETRY_NOT_SET)
+        {
+            LogRel(("PcBios: ATA failed to update LCHS geometry, backend refused\n"));
+            rc = VINF_SUCCESS;
+        }
+    }
+
+    *pLCHSGeometry = LCHSGeometry;
+
+    return rc;
+}
+
+
+/**
+ * Get logical CHS geometry for a hard disk, intended for SCSI/SAS drives
+ * with no physical geometry.
+ *
+ * @returns VBox status code.
+ * @param   pHardDisk     The hard disk.
+ * @param   pLCHSGeometry Where to store the geometry settings.
+ */
+static int getLogicalDiskGeometry(PPDMIMEDIA pHardDisk, PPDMMEDIAGEOMETRY pLCHSGeometry)
+{
+    PDMMEDIAGEOMETRY LCHSGeometry;
+    int rc = VINF_SUCCESS;
+
+    rc = pHardDisk->pfnBiosGetLCHSGeometry(pHardDisk, &LCHSGeometry);
+    if (   rc == VERR_PDM_GEOMETRY_NOT_SET
+        || LCHSGeometry.cCylinders == 0
+        || LCHSGeometry.cHeads == 0
+        || LCHSGeometry.cHeads > 255
+        || LCHSGeometry.cSectors == 0
+        || LCHSGeometry.cSectors > 63)
+    {
+        /* Unlike the ATA case, if the image does not provide valid logical
+         * geometry, we leave things alone and let the BIOS decide what the
+         * logical geometry should be.
+         */
+        rc = VERR_PDM_GEOMETRY_NOT_SET;
+    }
+    else
+        *pLCHSGeometry = LCHSGeometry;
+
+    return rc;
+}
+
+
+/**
+ * Get BIOS boot code from enmBootDevice in order
+ *
+ * @todo r=bird: This is a rather silly function since the conversion is 1:1.
+ */
+static uint8_t getBiosBootCode(PDEVPCBIOS pThis, unsigned iOrder)
+{
+    switch (pThis->aenmBootDevice[iOrder])
+    {
+        case DEVPCBIOSBOOT_NONE:
+            return 0;
+        case DEVPCBIOSBOOT_FLOPPY:
+            return 1;
+        case DEVPCBIOSBOOT_HD:
+            return 2;
+        case DEVPCBIOSBOOT_DVD:
+            return 3;
+        case DEVPCBIOSBOOT_LAN:
+            return 4;
+        default:
+            AssertMsgFailed(("aenmBootDevice[%d]=%d\n", iOrder, pThis->aenmBootDevice[iOrder]));
+            return 0;
+    }
+}
+
+
+/**
+ * @interface_method_impl{PDMDEVREG,pfnInitComplete}
+ *
+ * This routine will write information needed by the bios to the CMOS.
+ *
+ * @see     http://www.brl.ntt.co.jp/people/takehiko/interrupt/CMOS.LST.txt for
+ *          a description of standard and non-standard CMOS registers.
+ */
+static DECLCALLBACK(int) pcbiosInitComplete(PPDMDEVINS pDevIns)
+{
+    PDEVPCBIOS      pThis = PDMDEVINS_2_DATA(pDevIns, PDEVPCBIOS);
+    uint32_t        u32;
+    unsigned        i;
+    PPDMIMEDIA      apHDs[4] = {0};
+    LogFlow(("pcbiosInitComplete:\n"));
+
+    uint64_t const  cbRamSize  = PDMDevHlpMMPhysGetRamSize(pDevIns);
+    uint32_t const  cbBelow4GB = PDMDevHlpMMPhysGetRamSizeBelow4GB(pDevIns);
+    uint64_t const  cbAbove4GB = PDMDevHlpMMPhysGetRamSizeAbove4GB(pDevIns);
+
+    /*
+     * Memory sizes.
+     */
+    /* base memory. */
+    u32 = cbRamSize > 640 ? 640 : (uint32_t)cbRamSize / _1K; /* <-- this test is wrong, but it doesn't matter since we never assign less than 1MB */
+    pcbiosCmosWrite(pDevIns, 0x15, RT_BYTE1(u32));  /* 15h - Base Memory in K, Low Byte */
+    pcbiosCmosWrite(pDevIns, 0x16, RT_BYTE2(u32));  /* 16h - Base Memory in K, High Byte */
+
+    /* Extended memory, up to 65MB */
+    u32 = cbRamSize >= 65 * _1M ? 0xffff : ((uint32_t)cbRamSize - _1M) / _1K;
+    pcbiosCmosWrite(pDevIns, 0x17, RT_BYTE1(u32));  /* 17h - Extended Memory in K, Low Byte */
+    pcbiosCmosWrite(pDevIns, 0x18, RT_BYTE2(u32));  /* 18h - Extended Memory in K, High Byte */
+    pcbiosCmosWrite(pDevIns, 0x30, RT_BYTE1(u32));  /* 30h - Extended Memory in K, Low Byte */
+    pcbiosCmosWrite(pDevIns, 0x31, RT_BYTE2(u32));  /* 31h - Extended Memory in K, High Byte */
+
+    /* Bochs BIOS specific? Anyway, it's the amount of memory above 16MB
+       and below 4GB (as it can only hold 4GB-16M). We have to chop off the
+       top 32MB or it conflict with what the ACPI tables return. (Should these
+       be adjusted, we still have to chop it at 0xfffc0000 or it'll conflict
+       with the high BIOS mapping.) */
+    if (cbRamSize > 16 * _1M)
+        u32 = (RT_MIN(cbBelow4GB, UINT32_C(0xfe000000)) - 16U * _1M) / _64K;
+    else
+        u32 = 0;
+    pcbiosCmosWrite(pDevIns, 0x34, RT_BYTE1(u32));
+    pcbiosCmosWrite(pDevIns, 0x35, RT_BYTE2(u32));
+
+    /* Bochs/VBox BIOS specific way of specifying memory above 4GB in 64KB units.
+       Bochs got these in a different location which we've already used for SATA,
+       it also lacks the last two. */
+    uint64_t c64KBAbove4GB = cbAbove4GB / _64K;
+    /* Make sure it doesn't hit the limits of the current BIOS code (RAM limit of ~255TB). */
+    AssertLogRelMsgReturn((c64KBAbove4GB >> (3 * 8)) < 255, ("%#RX64\n", c64KBAbove4GB), VERR_OUT_OF_RANGE);
+    pcbiosCmosWrite(pDevIns, 0x61, RT_BYTE1(c64KBAbove4GB));
+    pcbiosCmosWrite(pDevIns, 0x62, RT_BYTE2(c64KBAbove4GB));
+    pcbiosCmosWrite(pDevIns, 0x63, RT_BYTE3(c64KBAbove4GB));
+    pcbiosCmosWrite(pDevIns, 0x64, RT_BYTE4(c64KBAbove4GB));
+    pcbiosCmosWrite(pDevIns, 0x65, RT_BYTE5(c64KBAbove4GB));
+
+    /*
+     * Number of CPUs.
+     */
+    pcbiosCmosWrite(pDevIns, 0x60, pThis->cCpus & 0xff);
+
+    /*
+     * APIC mode.
+     */
+    pcbiosCmosWrite(pDevIns, 0x78, pThis->u8APICMode);
+
+    /*
+     * Bochs BIOS specifics - boot device.
+     * We do both new and old (ami-style) settings.
+     * See rombios.c line ~7215 (int19_function).
+     */
+
+    uint8_t reg3d = getBiosBootCode(pThis, 0) | (getBiosBootCode(pThis, 1) << 4);
+    uint8_t reg38 = /* pcbiosCmosRead(pDevIns, 0x38) | */ getBiosBootCode(pThis, 2) << 4;
+    /* This is an extension. Bochs BIOS normally supports only 3 boot devices. */
+    uint8_t reg3c = getBiosBootCode(pThis, 3) | (pThis->uBootDelay << 4);
+    pcbiosCmosWrite(pDevIns, 0x3d, reg3d);
+    pcbiosCmosWrite(pDevIns, 0x38, reg38);
+    pcbiosCmosWrite(pDevIns, 0x3c, reg3c);
+
+    /*
+     * PXE debug option.
+     */
+    pcbiosCmosWrite(pDevIns, 0x3f, pThis->u8PXEDebug);
+
+    /*
+     * Network boot device list.
+     */
+    for (i = 0; i < NET_BOOT_DEVS; ++i)
+    {
+        pcbiosCmosWrite(pDevIns, 0x82 + i * 2, RT_BYTE1(pThis->au16NetBootDev[i]));
+        pcbiosCmosWrite(pDevIns, 0x83 + i * 2, RT_BYTE2(pThis->au16NetBootDev[i]));
+    }
+
+    /*
+     * Floppy drive type.
+     */
+    uint32_t cFDs = 0;
+    u32 = 0;
+    for (i = 0; i < 2; i++)
+    {
+        PPDMIBASE pBase;
+        int rc = PDMDevHlpQueryLun(pDevIns, pThis->pszFDDevice, 0, i, &pBase);
+        if (RT_SUCCESS(rc))
+        {
+            PPDMIMEDIA pFD = PDMIBASE_QUERY_INTERFACE(pBase, PDMIMEDIA);
+            if (pFD)
+            {
+                cFDs++;
+                unsigned cShift = i == 0 ? 4 : 0;
+                switch (pFD->pfnGetType(pFD))
+                {
+                    case PDMMEDIATYPE_FLOPPY_360:       u32 |= 1  << cShift; break;
+                    case PDMMEDIATYPE_FLOPPY_1_20:      u32 |= 2  << cShift; break;
+                    case PDMMEDIATYPE_FLOPPY_720:       u32 |= 3  << cShift; break;
+                    case PDMMEDIATYPE_FLOPPY_1_44:      u32 |= 4  << cShift; break;
+                    case PDMMEDIATYPE_FLOPPY_2_88:      u32 |= 5  << cShift; break;
+                    case PDMMEDIATYPE_FLOPPY_FAKE_15_6: u32 |= 14 << cShift; break;
+                    case PDMMEDIATYPE_FLOPPY_FAKE_63_5: u32 |= 15 << cShift; break;
+                    default:                        AssertFailed(); break;
+                }
+            }
+        }
+    }
+    pcbiosCmosWrite(pDevIns, 0x10, u32);                                        /* 10h - Floppy Drive Type */
+
+    /*
+     * Equipment byte.
+     */
+    if (cFDs > 0)
+        u32 = ((cFDs - 1) << 6) | 0x01;    /* floppy installed, additional drives. */
+    else
+        u32 = 0x00;                        /* floppy not installed. */
+    u32 |= RT_BIT(1);                      /* math coprocessor installed  */
+    u32 |= RT_BIT(2);                      /* keyboard enabled (or mouse?) */
+    u32 |= RT_BIT(3);                      /* display enabled (monitory type is 0, i.e. vga) */
+    pcbiosCmosWrite(pDevIns, 0x14, u32);                                        /* 14h - Equipment Byte */
+
+    /*
+     * IDE harddisks.
+     */
+    for (i = 0; i < RT_ELEMENTS(apHDs); i++)
+    {
+        PPDMIBASE pBase;
+        int rc = PDMDevHlpQueryLun(pDevIns, pThis->pszHDDevice, 0, i, &pBase);
+        if (RT_SUCCESS(rc))
+            apHDs[i] = PDMIBASE_QUERY_INTERFACE(pBase, PDMIMEDIA);
+        if (   apHDs[i]
+            && (   apHDs[i]->pfnGetType(apHDs[i]) != PDMMEDIATYPE_HARD_DISK
+                || !apHDs[i]->pfnBiosIsVisible(apHDs[i])))
+            apHDs[i] = NULL;
+        if (apHDs[i])
+        {
+            PDMMEDIAGEOMETRY LCHSGeometry;
+            int rc2 = setLogicalDiskGeometry(pBase, apHDs[i], &LCHSGeometry);
+            AssertRC(rc2);
+
+            if (i < 4)
+            {
+                /* Award BIOS extended drive types for first to fourth disk.
+                 * Used by the BIOS for setting the logical geometry. */
+                int offType, offInfo;
+                switch (i)
+                {
+                    case 0:
+                        offType = 0x19;
+                        offInfo = 0x1e;
+                        break;
+                    case 1:
+                        offType = 0x1a;
+                        offInfo = 0x26;
+                        break;
+                    case 2:
+                        offType = 0x00;
+                        offInfo = 0x67;
+                        break;
+                    case 3:
+                    default:
+                        offType = 0x00;
+                        offInfo = 0x70;
+                        break;
+                }
+                pcbiosCmosInitHardDisk(pDevIns, offType, offInfo,
+                                       &LCHSGeometry);
+            }
+            LogRel(("PcBios: ATA LUN#%d LCHS=%u/%u/%u\n", i, LCHSGeometry.cCylinders, LCHSGeometry.cHeads, LCHSGeometry.cSectors));
+        }
+    }
+
+    /* 0Fh means extended and points to 19h, 1Ah */
+    u32 = (apHDs[0] ? 0xf0 : 0) | (apHDs[1] ? 0x0f : 0);
+    pcbiosCmosWrite(pDevIns, 0x12, u32);
+
+    /*
+     * SATA harddisks.
+     */
+    if (pThis->pszSataDevice)
+    {
+        /* Clear pointers to the block devices. */
+        for (i = 0; i < RT_ELEMENTS(apHDs); i++)
+            apHDs[i] = NULL;
+
+        for (i = 0; i < RT_ELEMENTS(apHDs); i++)
+        {
+            PPDMIBASE pBase;
+            int rc = PDMDevHlpQueryLun(pDevIns, pThis->pszSataDevice, 0, pThis->iSataHDLUN[i], &pBase);
+            if (RT_SUCCESS(rc))
+                apHDs[i] = PDMIBASE_QUERY_INTERFACE(pBase, PDMIMEDIA);
+            if (   apHDs[i]
+                && (   apHDs[i]->pfnGetType(apHDs[i]) != PDMMEDIATYPE_HARD_DISK
+                    || !apHDs[i]->pfnBiosIsVisible(apHDs[i])))
+                apHDs[i] = NULL;
+            if (apHDs[i])
+            {
+                PDMMEDIAGEOMETRY LCHSGeometry;
+                rc = setLogicalDiskGeometry(pBase, apHDs[i], &LCHSGeometry);
+                AssertRC(rc);
+
+                if (i < 4)
+                {
+                    /* Award BIOS extended drive types for first to fourth disk.
+                     * Used by the BIOS for setting the logical geometry. */
+                    int offInfo;
+                    switch (i)
+                    {
+                        case 0:
+                            offInfo = 0x40;
+                            break;
+                        case 1:
+                            offInfo = 0x48;
+                            break;
+                        case 2:
+                            offInfo = 0x50;
+                            break;
+                        case 3:
+                        default:
+                            offInfo = 0x58;
+                            break;
+                    }
+                    pcbiosCmosInitHardDisk(pDevIns, 0x00, offInfo,
+                                           &LCHSGeometry);
+                }
+                LogRel(("PcBios: SATA LUN#%d LCHS=%u/%u/%u\n", i, LCHSGeometry.cCylinders, LCHSGeometry.cHeads, LCHSGeometry.cSectors));
+            }
+        }
+    }
+
+    /*
+     * SCSI harddisks. Not handled quite the same as SATA.
+     */
+    if (pThis->pszScsiDevice)
+    {
+        /* Clear pointers to the block devices. */
+        for (i = 0; i < RT_ELEMENTS(apHDs); i++)
+            apHDs[i] = NULL;
+
+        for (i = 0; i < RT_ELEMENTS(apHDs); i++)
+        {
+            PPDMIBASE pBase;
+            int rc = PDMDevHlpQueryLun(pDevIns, pThis->pszScsiDevice, 0, pThis->iScsiHDLUN[i], &pBase);
+            if (RT_SUCCESS(rc))
+                apHDs[i] = PDMIBASE_QUERY_INTERFACE(pBase, PDMIMEDIA);
+            if (   apHDs[i]
+                && (   apHDs[i]->pfnGetType(apHDs[i]) != PDMMEDIATYPE_HARD_DISK
+                    || !apHDs[i]->pfnBiosIsVisible(apHDs[i])))
+                apHDs[i] = NULL;
+            if (apHDs[i])
+            {
+                PDMMEDIAGEOMETRY LCHSGeometry;
+                rc = getLogicalDiskGeometry(apHDs[i], &LCHSGeometry);
+
+                if (i < 4 && RT_SUCCESS(rc))
+                {
+                    /* Extended drive information (for SCSI disks).
+                     * Used by the BIOS for setting the logical geometry, but
+                     * only if the image provided valid data.
+                     */
+                    int offInfo;
+                    switch (i)
+                    {
+                        case 0:
+                            offInfo = 0x90;
+                            break;
+                        case 1:
+                            offInfo = 0x98;
+                            break;
+                        case 2:
+                            offInfo = 0xa0;
+                            break;
+                        case 3:
+                        default:
+                            offInfo = 0xa8;
+                            break;
+                    }
+                    pcbiosCmosInitHardDisk(pDevIns, 0x00, offInfo, &LCHSGeometry);
+                    LogRel(("PcBios: SCSI LUN#%d LCHS=%u/%u/%u\n", i, LCHSGeometry.cCylinders, LCHSGeometry.cHeads, LCHSGeometry.cSectors));
+                }
+                else
+                    LogRel(("PcBios: SCSI LUN#%d LCHS not provided\n", i));
+            }
+        }
+    }
+
+    /* Calculate and store AT-style CMOS checksum. */
+    uint16_t    cksum = 0;
+    for (i = 0x10; i < 0x2e; ++i)
+        cksum += pcbiosCmosRead(pDevIns, i);
+    pcbiosCmosWrite(pDevIns, 0x2e, RT_BYTE1(cksum));
+    pcbiosCmosWrite(pDevIns, 0x2f, RT_BYTE2(cksum));
+
+    LogFlow(("%s: returns VINF_SUCCESS\n", __FUNCTION__));
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * @interface_method_impl{PDMDEVREG,pfnMemSetup}
+ */
+static DECLCALLBACK(void) pcbiosMemSetup(PPDMDEVINS pDevIns, PDMDEVMEMSETUPCTX enmCtx)
+{
+    RT_NOREF1(enmCtx);
+    PDEVPCBIOS pThis = PDMDEVINS_2_DATA(pDevIns, PDEVPCBIOS);
+    LogFlow(("pcbiosMemSetup:\n"));
+
+    if (pThis->u8IOAPIC)
+        FwCommonPlantMpsFloatPtr(pDevIns, pThis->u32MPTableAddr);
+
+    /*
+     * Re-shadow the LAN ROM image and make it RAM/RAM.
+     *
+     * This is normally done by the BIOS code, but since we're currently lacking
+     * the chipset support for this we do it here (and in the constructor).
+     */
+    uint32_t    cPages = RT_ALIGN_64(pThis->cbLanBoot, GUEST_PAGE_SIZE) >> GUEST_PAGE_SHIFT;
+    RTGCPHYS    GCPhys = VBOX_LANBOOT_SEG << 4;
+    while (cPages > 0)
+    {
+        uint8_t abPage[GUEST_PAGE_SIZE];
+        int     rc;
+
+        /* Read the (original) ROM page and write it back to the RAM page. */
+        rc = PDMDevHlpROMProtectShadow(pDevIns, GCPhys, GUEST_PAGE_SIZE, PGMROMPROT_READ_ROM_WRITE_RAM);
+        AssertLogRelRC(rc);
+
+        rc = PDMDevHlpPhysRead(pDevIns, GCPhys, abPage, GUEST_PAGE_SIZE);
+        AssertLogRelRC(rc);
+        if (RT_FAILURE(rc))
+            memset(abPage, 0xcc, sizeof(abPage));
+
+        rc = PDMDevHlpPhysWrite(pDevIns, GCPhys, abPage, GUEST_PAGE_SIZE);
+        AssertLogRelRC(rc);
+
+        /* Switch to the RAM/RAM mode. */
+        rc = PDMDevHlpROMProtectShadow(pDevIns, GCPhys, GUEST_PAGE_SIZE, PGMROMPROT_READ_RAM_WRITE_RAM);
+        AssertLogRelRC(rc);
+
+        /* Advance */
+        GCPhys += GUEST_PAGE_SIZE;
+        cPages--;
+    }
+}
+
+
+/**
+ * @interface_method_impl{PDMDEVREG,pfnDestruct}
+ */
+static DECLCALLBACK(int) pcbiosDestruct(PPDMDEVINS pDevIns)
+{
+    PDMDEV_CHECK_VERSIONS_RETURN_QUIET(pDevIns);
+    PDEVPCBIOS  pThis = PDMDEVINS_2_DATA(pDevIns, PDEVPCBIOS);
+    LogFlow(("pcbiosDestruct:\n"));
+
+    /*
+     * Free MM heap pointers.
+     */
+    if (pThis->pu8PcBios)
+    {
+        PDMDevHlpMMHeapFree(pDevIns, pThis->pu8PcBios);
+        pThis->pu8PcBios = NULL;
+    }
+
+    if (pThis->pszPcBiosFile)
+    {
+        PDMDevHlpMMHeapFree(pDevIns, pThis->pszPcBiosFile);
+        pThis->pszPcBiosFile = NULL;
+    }
+
+    if (pThis->pu8LanBoot)
+    {
+        PDMDevHlpMMHeapFree(pDevIns, pThis->pu8LanBoot);
+        pThis->pu8LanBoot = NULL;
+    }
+
+    if (pThis->pszLanBootFile)
+    {
+        PDMDevHlpMMHeapFree(pDevIns, pThis->pszLanBootFile);
+        pThis->pszLanBootFile = NULL;
+    }
+
+    if (pThis->pszHDDevice)
+    {
+        PDMDevHlpMMHeapFree(pDevIns, pThis->pszHDDevice);
+        pThis->pszHDDevice = NULL;
+    }
+
+    if (pThis->pszFDDevice)
+    {
+        PDMDevHlpMMHeapFree(pDevIns, pThis->pszFDDevice);
+        pThis->pszFDDevice = NULL;
+    }
+
+    if (pThis->pszSataDevice)
+    {
+        PDMDevHlpMMHeapFree(pDevIns, pThis->pszSataDevice);
+        pThis->pszSataDevice = NULL;
+    }
+
+    if (pThis->pszScsiDevice)
+    {
+        PDMDevHlpMMHeapFree(pDevIns, pThis->pszScsiDevice);
+        pThis->pszScsiDevice = NULL;
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Convert config value to DEVPCBIOSBOOT.
+ *
+ * @returns VBox status code.
+ * @param   pDevIns         Device instance data.
+ * @param   pCfg            Configuration handle.
+ * @param   pszParam        The name of the value to read.
+ * @param   penmBoot        Where to store the boot method.
+ */
+static int pcbiosBootFromCfg(PPDMDEVINS pDevIns, PCFGMNODE pCfg, const char *pszParam, DEVPCBIOSBOOT *penmBoot)
+{
+    PCPDMDEVHLPR3 pHlp = pDevIns->pHlpR3;
+
+    char szBuf[64];
+    int rc = pHlp->pfnCFGMQueryString(pCfg, pszParam, szBuf, sizeof(szBuf));
+    if (RT_FAILURE(rc))
+        return PDMDevHlpVMSetError(pDevIns, rc, RT_SRC_POS,
+                                   N_("Configuration error: Querying \"%s\" as a string failed"), pszParam);
+
+    if (!strcmp(szBuf, "DVD") || !strcmp(szBuf, "CDROM"))
+        *penmBoot = DEVPCBIOSBOOT_DVD;
+    else if (!strcmp(szBuf, "IDE"))
+        *penmBoot = DEVPCBIOSBOOT_HD;
+    else if (!strcmp(szBuf, "FLOPPY"))
+        *penmBoot = DEVPCBIOSBOOT_FLOPPY;
+    else if (!strcmp(szBuf, "LAN"))
+        *penmBoot = DEVPCBIOSBOOT_LAN;
+    else if (!strcmp(szBuf, "NONE"))
+        *penmBoot = DEVPCBIOSBOOT_NONE;
+    else
+        rc = PDMDevHlpVMSetError(pDevIns, VERR_INVALID_PARAMETER, RT_SRC_POS,
+                                 N_("Configuration error: The \"%s\" value \"%s\" is unknown"),  pszParam, szBuf);
+    return rc;
+}
+
+
+/**
+ * @interface_method_impl{PDMDEVREG,pfnConstruct}
+ */
+static DECLCALLBACK(int)  pcbiosConstruct(PPDMDEVINS pDevIns, int iInstance, PCFGMNODE pCfg)
+{
+    PDMDEV_CHECK_VERSIONS_RETURN(pDevIns);
+    PDEVPCBIOS      pThis   = PDMDEVINS_2_DATA(pDevIns, PDEVPCBIOS);
+    PCPDMDEVHLPR3   pHlp    = pDevIns->pHlpR3;
+    int             rc;
+    int             cb;
+    Assert(iInstance == 0); RT_NOREF(iInstance);
+
+    /*
+     * Validate configuration.
+     */
+    PDMDEV_VALIDATE_CONFIG_RETURN(pDevIns,
+                                  "BootDevice0"
+                                  "|BootDevice1"
+                                  "|BootDevice2"
+                                  "|BootDevice3"
+                                  "|HardDiskDevice"
+                                  "|SataHardDiskDevice"
+                                  "|SataLUN1"
+                                  "|SataLUN2"
+                                  "|SataLUN3"
+                                  "|SataLUN4"
+                                  "|ScsiHardDiskDevice"
+                                  "|ScsiLUN1"
+                                  "|ScsiLUN2"
+                                  "|ScsiLUN3"
+                                  "|ScsiLUN4"
+                                  "|FloppyDevice"
+                                  "|DelayBoot"
+                                  "|BiosRom"
+                                  "|LanBootRom"
+                                  "|PXEDebug"
+                                  "|UUID"
+                                  "|UuidLe"
+                                  "|IOAPIC"
+                                  "|APIC"
+                                  "|NumCPUs"
+                                  "|McfgBase"
+                                  "|McfgLength"
+                                  "|DmiBIOSFirmwareMajor"
+                                  "|DmiBIOSFirmwareMinor"
+                                  "|DmiBIOSReleaseDate"
+                                  "|DmiBIOSReleaseMajor"
+                                  "|DmiBIOSReleaseMinor"
+                                  "|DmiBIOSVendor"
+                                  "|DmiBIOSVersion"
+                                  "|DmiSystemFamily"
+                                  "|DmiSystemProduct"
+                                  "|DmiSystemSerial"
+                                  "|DmiSystemSKU"
+                                  "|DmiSystemUuid"
+                                  "|DmiSystemVendor"
+                                  "|DmiSystemVersion"
+                                  "|DmiBoardAssetTag"
+                                  "|DmiBoardBoardType"
+                                  "|DmiBoardLocInChass"
+                                  "|DmiBoardProduct"
+                                  "|DmiBoardSerial"
+                                  "|DmiBoardVendor"
+                                  "|DmiBoardVersion"
+                                  "|DmiChassisAssetTag"
+                                  "|DmiChassisSerial"
+                                  "|DmiChassisType"
+                                  "|DmiChassisVendor"
+                                  "|DmiChassisVersion"
+                                  "|DmiProcManufacturer"
+                                  "|DmiProcVersion"
+                                  "|DmiOEMVBoxVer"
+                                  "|DmiOEMVBoxRev"
+                                  "|DmiUseHostInfo"
+                                  "|DmiExposeMemoryTable"
+                                  "|DmiExposeProcInf"
+                                  "|CheckShutdownStatusForSoftReset"
+                                  "|ClearShutdownStatusOnHardReset"
+                                  ,
+                                  "NetBoot");
+    /*
+     * Init the data.
+     */
+    rc = pHlp->pfnCFGMQueryU16Def(pCfg, "NumCPUs", &pThis->cCpus, 1);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc, N_("Configuration error: Querying \"NumCPUs\" as integer failed"));
+
+    rc = pHlp->pfnCFGMQueryU64Def(pCfg, "McfgBase", &pThis->u64McfgBase, 0);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc, N_("Configuration error: Querying \"\" as integer failed"));
+    rc = pHlp->pfnCFGMQueryU64Def(pCfg, "McfgLength", &pThis->cbMcfgLength, 0);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc, N_("Configuration error: Querying \"McfgLength\" as integer failed"));
+
+
+    LogRel(("PcBios: [SMP] BIOS with %u CPUs\n", pThis->cCpus));
+
+    rc = pHlp->pfnCFGMQueryU8Def(pCfg, "IOAPIC", &pThis->u8IOAPIC, 1);
+    if (RT_FAILURE (rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc, N_("Configuration error: Failed to read \"IOAPIC\""));
+
+    rc = pHlp->pfnCFGMQueryU8Def(pCfg, "APIC", &pThis->u8APICMode, 1);
+    if (RT_FAILURE (rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc, N_("Configuration error: Failed to read \"APIC\""));
+
+    static const char * const s_apszBootDevices[] = { "BootDevice0", "BootDevice1", "BootDevice2", "BootDevice3" };
+    Assert(RT_ELEMENTS(s_apszBootDevices) == RT_ELEMENTS(pThis->aenmBootDevice));
+    for (unsigned i = 0; i < RT_ELEMENTS(pThis->aenmBootDevice); i++)
+    {
+        rc = pcbiosBootFromCfg(pDevIns, pCfg, s_apszBootDevices[i], &pThis->aenmBootDevice[i]);
+        if (RT_FAILURE(rc))
+            return rc;
+    }
+
+    rc = pHlp->pfnCFGMQueryStringAlloc(pCfg, "HardDiskDevice", &pThis->pszHDDevice);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc, N_("Configuration error: Querying \"HardDiskDevice\" as a string failed"));
+
+    rc = pHlp->pfnCFGMQueryStringAlloc(pCfg, "FloppyDevice", &pThis->pszFDDevice);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc, N_("Configuration error: Querying \"FloppyDevice\" as a string failed"));
+
+    rc = pHlp->pfnCFGMQueryStringAlloc(pCfg, "SataHardDiskDevice", &pThis->pszSataDevice);
+    if (rc == VERR_CFGM_VALUE_NOT_FOUND)
+        pThis->pszSataDevice = NULL;
+    else if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc, N_("Configuration error: Querying \"SataHardDiskDevice\" as a string failed"));
+
+    if (pThis->pszSataDevice)
+    {
+        static const char * const s_apszSataDisks[] = { "SataLUN1", "SataLUN2", "SataLUN3", "SataLUN4" };
+        Assert(RT_ELEMENTS(s_apszSataDisks) == RT_ELEMENTS(pThis->iSataHDLUN));
+        for (unsigned i = 0; i < RT_ELEMENTS(pThis->iSataHDLUN); i++)
+        {
+            rc = pHlp->pfnCFGMQueryU32(pCfg, s_apszSataDisks[i], &pThis->iSataHDLUN[i]);
+            if (rc == VERR_CFGM_VALUE_NOT_FOUND)
+                pThis->iSataHDLUN[i] = i;
+            else if (RT_FAILURE(rc))
+                return PDMDevHlpVMSetError(pDevIns, rc, RT_SRC_POS,
+                                           N_("Configuration error: Querying \"%s\" as a string failed"), s_apszSataDisks);
+        }
+    }
+
+    /* Repeat the exercise for SCSI drives. */
+    rc = pHlp->pfnCFGMQueryStringAlloc(pCfg, "ScsiHardDiskDevice", &pThis->pszScsiDevice);
+    if (rc == VERR_CFGM_VALUE_NOT_FOUND)
+        pThis->pszScsiDevice = NULL;
+    else if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc, N_("Configuration error: Querying \"ScsiHardDiskDevice\" as a string failed"));
+
+    if (pThis->pszScsiDevice)
+    {
+        static const char * const s_apszScsiDisks[] = { "ScsiLUN1", "ScsiLUN2", "ScsiLUN3", "ScsiLUN4" };
+        Assert(RT_ELEMENTS(s_apszScsiDisks) == RT_ELEMENTS(pThis->iScsiHDLUN));
+        for (unsigned i = 0; i < RT_ELEMENTS(pThis->iScsiHDLUN); i++)
+        {
+            rc = pHlp->pfnCFGMQueryU32(pCfg, s_apszScsiDisks[i], &pThis->iScsiHDLUN[i]);
+            if (rc == VERR_CFGM_VALUE_NOT_FOUND)
+                pThis->iScsiHDLUN[i] = i;
+            else if (RT_FAILURE(rc))
+                return PDMDevHlpVMSetError(pDevIns, rc, RT_SRC_POS,
+                                           N_("Configuration error: Querying \"%s\" as a string failed"), s_apszScsiDisks);
+        }
+    }
+
+    /* PXE debug logging option. */
+    rc = pHlp->pfnCFGMQueryU8Def(pCfg, "PXEDebug", &pThis->u8PXEDebug, false);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc, N_("Configuration error: Querying \"PXEDebug\" as integer failed"));
+
+
+    /*
+     * Register the I/O Ports.
+     */
+    IOMIOPORTHANDLE hIoPorts;
+    rc = PDMDevHlpIoPortCreateAndMap(pDevIns, 0x400 /*uPort*/, 4 /*cPorts*/, pcbiosIOPortDebugWrite, pcbiosIOPortDebugRead,
+                                     "Bochs PC BIOS - Panic & Debug", NULL, &hIoPorts);
+    AssertRCReturn(rc, rc);
+
+    rc = PDMDevHlpIoPortCreateIsa(pDevIns, 1 /*cPorts*/, pcbiosIOPortShutdownWrite, pcbiosIOPortShutdownRead, NULL /*pvUser*/,
+                                  "Bochs PC BIOS - Shutdown", NULL /*paExtDescs*/, &pThis->hIoPortShutdown);
+    AssertRCReturn(rc, rc);
+    rc = pcbiosRegisterShutdown(pDevIns, pThis, true /* fNewShutdownPort */);
+    AssertRCReturn(rc, rc);
+
+    /*
+     * Register SSM handlers, for remembering which shutdown port to use.
+     */
+    rc = PDMDevHlpSSMRegisterEx(pDevIns, PCBIOS_SSM_VERSION, 1 /* cbGuess */, NULL,
+                                NULL, NULL, NULL,
+                                NULL, pcbiosSaveExec, NULL,
+                                pcbiosLoadPrep, pcbiosLoadExec, pcbiosLoadDone);
+
+    /* Clear the net boot device list. All bits set invokes old behavior,
+     * as if no second CMOS bank was present.
+     */
+    memset(&pThis->au16NetBootDev, 0xff, sizeof(pThis->au16NetBootDev));
+
+    /*
+     * Determine the network boot order.
+     */
+    PCFGMNODE pCfgNetBoot = pHlp->pfnCFGMGetChild(pCfg, "NetBoot");
+    if (pCfgNetBoot == NULL)
+    {
+        /* Do nothing. */
+        rc = VINF_SUCCESS;
+    }
+    else
+    {
+        PCFGMNODE   pCfgNetBootDevice;
+        uint8_t     u8PciBus;
+        uint8_t     u8PciDev;
+        uint8_t     u8PciFn;
+        uint16_t    u16BusDevFn;
+        char        szIndex[] = "?";
+
+        Assert(pCfgNetBoot);
+        for (unsigned i = 0; i < NET_BOOT_DEVS; ++i)
+        {
+            szIndex[0] = '0' + i;
+            pCfgNetBootDevice = pHlp->pfnCFGMGetChild(pCfgNetBoot, szIndex);
+
+            rc = pHlp->pfnCFGMQueryU8(pCfgNetBootDevice, "PCIBusNo", &u8PciBus);
+            if (rc == VERR_CFGM_VALUE_NOT_FOUND || rc == VERR_CFGM_NO_PARENT)
+            {
+                /* Do nothing and stop iterating. */
+                rc = VINF_SUCCESS;
+                break;
+            }
+            else if (RT_FAILURE(rc))
+                return PDMDEV_SET_ERROR(pDevIns, rc,
+                                        N_("Configuration error: Querying \"Netboot/x/PCIBusNo\" as integer failed"));
+            rc = pHlp->pfnCFGMQueryU8(pCfgNetBootDevice, "PCIDeviceNo", &u8PciDev);
+            if (rc == VERR_CFGM_VALUE_NOT_FOUND || rc == VERR_CFGM_NO_PARENT)
+            {
+                /* Do nothing and stop iterating. */
+                rc = VINF_SUCCESS;
+                break;
+            }
+            else if (RT_FAILURE(rc))
+                return PDMDEV_SET_ERROR(pDevIns, rc,
+                                        N_("Configuration error: Querying \"Netboot/x/PCIDeviceNo\" as integer failed"));
+            rc = pHlp->pfnCFGMQueryU8(pCfgNetBootDevice, "PCIFunctionNo", &u8PciFn);
+            if (rc == VERR_CFGM_VALUE_NOT_FOUND || rc == VERR_CFGM_NO_PARENT)
+            {
+                /* Do nothing and stop iterating. */
+                rc = VINF_SUCCESS;
+                break;
+            }
+            else if (RT_FAILURE(rc))
+                return PDMDEV_SET_ERROR(pDevIns, rc,
+                                        N_("Configuration error: Querying \"Netboot/x/PCIFunctionNo\" as integer failed"));
+            u16BusDevFn = (((uint16_t)u8PciBus) << 8) | ((u8PciDev & 0x1F) << 3) | (u8PciFn & 0x7);
+            pThis->au16NetBootDev[i] = u16BusDevFn;
+        }
+    }
+
+    /*
+     * Get the system BIOS ROM file name.
+     */
+    rc = pHlp->pfnCFGMQueryStringAlloc(pCfg, "BiosRom", &pThis->pszPcBiosFile);
+    if (rc == VERR_CFGM_VALUE_NOT_FOUND)
+    {
+        pThis->pszPcBiosFile = NULL;
+        rc = VINF_SUCCESS;
+    }
+    else if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Querying \"BiosRom\" as a string failed"));
+    else if (!*pThis->pszPcBiosFile)
+    {
+        PDMDevHlpMMHeapFree(pDevIns, pThis->pszPcBiosFile);
+        pThis->pszPcBiosFile = NULL;
+    }
+
+    /*
+     * Get the CPU arch so we can load the appropriate ROMs.
+     */
+    CPUMMICROARCH const enmMicroarch = PDMDevHlpCpuGetGuestMicroarch(pDevIns);
+
+    if (pThis->pszPcBiosFile)
+    {
+        /*
+         * Load the BIOS ROM.
+         */
+        RTFILE hFilePcBios;
+        rc = RTFileOpen(&hFilePcBios, pThis->pszPcBiosFile,
+                        RTFILE_O_READ | RTFILE_O_OPEN | RTFILE_O_DENY_WRITE);
+        if (RT_SUCCESS(rc))
+        {
+            /* Figure the size and check restrictions. */
+            uint64_t cbPcBios;
+            rc = RTFileQuerySize(hFilePcBios, &cbPcBios);
+            if (RT_SUCCESS(rc))
+            {
+                pThis->cbPcBios = (uint32_t)cbPcBios;
+                if (    RT_ALIGN(pThis->cbPcBios, _64K) == pThis->cbPcBios
+                    &&  pThis->cbPcBios == cbPcBios
+                    &&  pThis->cbPcBios <= 32 * _64K
+                    &&  pThis->cbPcBios >= _64K)
+                {
+                    pThis->pu8PcBios = (uint8_t *)PDMDevHlpMMHeapAlloc(pDevIns, pThis->cbPcBios);
+                    if (pThis->pu8PcBios)
+                    {
+                        rc = RTFileRead(hFilePcBios, pThis->pu8PcBios, pThis->cbPcBios, NULL);
+                        if (RT_FAILURE(rc))
+                            rc = PDMDevHlpVMSetError(pDevIns, rc, RT_SRC_POS,
+                                                     N_("Error reading the BIOS image ('%s)"), pThis->pszPcBiosFile);
+                    }
+                    else
+                        rc = PDMDevHlpVMSetError(pDevIns, VERR_NO_MEMORY, RT_SRC_POS,
+                                                 N_("Failed to allocate %#x bytes for loading the BIOS image"),
+                                                 pThis->cbPcBios);
+                }
+                else
+                    rc = PDMDevHlpVMSetError(pDevIns, VERR_OUT_OF_RANGE, RT_SRC_POS,
+                                             N_("Invalid system BIOS file size ('%s'): %#llx (%llu)"),
+                                             pThis->pszPcBiosFile, cbPcBios, cbPcBios);
+            }
+            else
+                rc = PDMDevHlpVMSetError(pDevIns, rc, RT_SRC_POS,
+                                         N_("Failed to query the system BIOS file size ('%s')"),
+                                         pThis->pszPcBiosFile);
+            RTFileClose(hFilePcBios);
+        }
+        else
+            rc = PDMDevHlpVMSetError(pDevIns, rc, RT_SRC_POS,
+                                     N_("Failed to open system BIOS file '%s'"), pThis->pszPcBiosFile);
+        if (RT_FAILURE(rc))
+            return rc;
+
+        LogRel(("PcBios: Using BIOS ROM '%s' with a size of %#x bytes\n", pThis->pszPcBiosFile, pThis->cbPcBios));
+    }
+    else
+    {
+        /*
+         * Use one of the embedded BIOS ROM images.
+         */
+        uint8_t const *pbBios;
+        uint32_t       cbBios;
+        if (   enmMicroarch == kCpumMicroarch_Intel_8086
+            || enmMicroarch == kCpumMicroarch_Intel_80186
+            || enmMicroarch == kCpumMicroarch_NEC_V20
+            || enmMicroarch == kCpumMicroarch_NEC_V30)
+        {
+            pbBios = g_abPcBiosBinary8086;
+            cbBios = g_cbPcBiosBinary8086;
+            LogRel(("PcBios: Using the 8086 BIOS image!\n"));
+        }
+        else if (enmMicroarch == kCpumMicroarch_Intel_80286)
+        {
+            pbBios = g_abPcBiosBinary286;
+            cbBios = g_cbPcBiosBinary286;
+            LogRel(("PcBios: Using the 286 BIOS image!\n"));
+        }
+        else
+        {
+            pbBios = g_abPcBiosBinary386;
+            cbBios = g_cbPcBiosBinary386;
+            LogRel(("PcBios: Using the 386+ BIOS image.\n"));
+        }
+        pThis->pu8PcBios = (uint8_t *)PDMDevHlpMMHeapAlloc(pDevIns, cbBios);
+        if (pThis->pu8PcBios)
+        {
+            pThis->cbPcBios = cbBios;
+            memcpy(pThis->pu8PcBios, pbBios, cbBios);
+        }
+        else
+            return PDMDevHlpVMSetError(pDevIns, VERR_NO_MEMORY, RT_SRC_POS,
+                                       N_("Failed to allocate %#x bytes for loading the embedded BIOS image"), cbBios);
+    }
+    const uint8_t *pu8PcBiosBinary = pThis->pu8PcBios;
+    uint32_t       cbPcBiosBinary  = pThis->cbPcBios;
+
+    /*
+     * Query the machine's UUID for SMBIOS/DMI use.
+     */
+    RTUUID  uuid;
+    rc = pHlp->pfnCFGMQueryBytes(pCfg, "UUID", &uuid, sizeof(uuid));
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Querying \"UUID\" failed"));
+
+    bool fUuidLe;
+    rc = pHlp->pfnCFGMQueryBoolDef(pCfg, "UuidLe", &fUuidLe, false);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Querying \"UuidLe\" failed"));
+
+    if (!fUuidLe)
+    {
+        /*
+         * UUIDs are stored little endian actually (see chapter 7.2.1 System — UUID
+         * of the DMI/SMBIOS spec) but to not force reactivation of existing guests we have
+         * to carry this bug along... (see also DevEFI.cpp when changing this)
+         *
+         * Convert the UUID to network byte order. Not entirely straightforward as
+         * parts are MSB already...
+         */
+        uuid.Gen.u32TimeLow = RT_H2BE_U32(uuid.Gen.u32TimeLow);
+        uuid.Gen.u16TimeMid = RT_H2BE_U16(uuid.Gen.u16TimeMid);
+        uuid.Gen.u16TimeHiAndVersion = RT_H2BE_U16(uuid.Gen.u16TimeHiAndVersion);
+    }
+
+    uint16_t cbDmiTables = 0;
+    uint16_t cDmiTables = 0;
+    rc = FwCommonPlantDMITable(pDevIns, pThis->au8DMIPage, VBOX_DMI_TABLE_SIZE,
+                               &uuid, pCfg, pThis->cCpus, &cbDmiTables, &cDmiTables,
+                               false /*fUefi*/);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /* Look for _SM_/_DMI_ anchor strings within the BIOS and replace the table headers. */
+    unsigned       offAnchor  = ~0U;
+    unsigned const cbToSearch = pThis->cbPcBios - 32;
+    for (unsigned off = 0; off <= cbToSearch; off += 16)
+    {
+        if (   pThis->pu8PcBios[off + 0x00] != '_'
+            || pThis->pu8PcBios[off + 0x01] != 'S'
+            || pThis->pu8PcBios[off + 0x02] != 'M'
+            || pThis->pu8PcBios[off + 0x03] != '_'
+            || pThis->pu8PcBios[off + 0x10] != '_'
+            || pThis->pu8PcBios[off + 0x11] != 'D'
+            || pThis->pu8PcBios[off + 0x12] != 'M'
+            || pThis->pu8PcBios[off + 0x13] != 'I'
+            || pThis->pu8PcBios[off + 0x14] != '_')
+        { /* likely */ }
+        else
+        {
+            offAnchor = off;
+            FwCommonPlantSmbiosAndDmiHdrs(pDevIns, pThis->pu8PcBios + off, cbDmiTables, cDmiTables);
+            break;
+        }
+    }
+    AssertLogRel(offAnchor <= cbToSearch);
+
+    if (pThis->u8IOAPIC)
+    {
+        pThis->u32MPTableAddr = VBOX_DMI_TABLE_BASE + VBOX_DMI_TABLE_SIZE;
+        FwCommonPlantMpsTable(pDevIns, pThis->au8DMIPage /* aka VBOX_DMI_TABLE_BASE */ + VBOX_DMI_TABLE_SIZE,
+                              _4K - VBOX_DMI_TABLE_SIZE, pThis->cCpus);
+        LogRel(("PcBios: MPS table at %08x\n", pThis->u32MPTableAddr));
+    }
+
+    rc = PDMDevHlpROMRegister(pDevIns, VBOX_DMI_TABLE_BASE, _4K, pThis->au8DMIPage, _4K,
+                              PGMPHYS_ROM_FLAGS_PERMANENT_BINARY, "DMI tables");
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Map the BIOS into memory.
+     * There are two mappings:
+     *      1. 0x000e0000 to 0x000fffff contains the last 128 kb of the bios.
+     *         The bios code might be 64 kb in size, and will then start at 0xf0000.
+     *      2. 0xfffxxxxx to 0xffffffff contains the entire bios.
+     */
+    AssertReleaseMsg(cbPcBiosBinary >= _64K, ("cbPcBiosBinary=%#x\n", cbPcBiosBinary));
+    AssertReleaseMsg(RT_ALIGN_Z(cbPcBiosBinary, _64K) == cbPcBiosBinary,
+                     ("cbPcBiosBinary=%#x\n", cbPcBiosBinary));
+    cb = RT_MIN(cbPcBiosBinary, 128 * _1K); /* Effectively either 64 or 128K. */
+    rc = PDMDevHlpROMRegister(pDevIns, 0x00100000 - cb, cb, &pu8PcBiosBinary[cbPcBiosBinary - cb], cb,
+                              PGMPHYS_ROM_FLAGS_PERMANENT_BINARY, "PC BIOS - 0xfffff");
+    if (RT_FAILURE(rc))
+        return rc;
+    rc = PDMDevHlpROMRegister(pDevIns, (uint32_t)-(int32_t)cbPcBiosBinary, cbPcBiosBinary, pu8PcBiosBinary, cbPcBiosBinary,
+                              PGMPHYS_ROM_FLAGS_PERMANENT_BINARY, "PC BIOS - 0xffffffff");
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Get the LAN boot ROM file name.
+     */
+    rc = pHlp->pfnCFGMQueryStringAlloc(pCfg, "LanBootRom", &pThis->pszLanBootFile);
+    if (rc == VERR_CFGM_VALUE_NOT_FOUND)
+    {
+        pThis->pszLanBootFile = NULL;
+        rc = VINF_SUCCESS;
+    }
+    else if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                N_("Configuration error: Querying \"LanBootRom\" as a string failed"));
+    else if (!*pThis->pszLanBootFile)
+    {
+        PDMDevHlpMMHeapFree(pDevIns, pThis->pszLanBootFile);
+        pThis->pszLanBootFile = NULL;
+    }
+
+    /*
+     * Not loading LAN ROM for old CPUs.
+     */
+    if (   enmMicroarch != kCpumMicroarch_Intel_8086
+        && enmMicroarch != kCpumMicroarch_Intel_80186
+        && enmMicroarch != kCpumMicroarch_NEC_V20
+        && enmMicroarch != kCpumMicroarch_NEC_V30
+        && enmMicroarch != kCpumMicroarch_Intel_80286)
+    {
+        const uint8_t  *pu8LanBootBinary = NULL;
+        uint64_t        cbLanBootBinary;
+        uint64_t        cbFileLanBoot = 0;
+
+        /*
+         * Open the LAN boot ROM and figure it size.
+         * Determine the LAN boot ROM size, open specified ROM file in the process.
+         */
+        if (pThis->pszLanBootFile)
+        {
+            RTFILE hFileLanBoot = NIL_RTFILE;
+            rc = RTFileOpen(&hFileLanBoot, pThis->pszLanBootFile,
+                            RTFILE_O_READ | RTFILE_O_OPEN | RTFILE_O_DENY_WRITE);
+            if (RT_SUCCESS(rc))
+            {
+                rc = RTFileQuerySize(hFileLanBoot, &cbFileLanBoot);
+                if (RT_SUCCESS(rc))
+                {
+                    if (cbFileLanBoot <= _64K - (VBOX_LANBOOT_SEG << 4 & 0xffff))
+                    {
+                        LogRel(("PcBios: Using LAN ROM '%s' with a size of %#x bytes\n", pThis->pszLanBootFile, cbFileLanBoot));
+
+                        /*
+                         * Allocate buffer for the LAN boot ROM data and load it.
+                         */
+                        pThis->pu8LanBoot = (uint8_t *)PDMDevHlpMMHeapAllocZ(pDevIns, cbFileLanBoot);
+                        if (pThis->pu8LanBoot)
+                        {
+                            rc = RTFileRead(hFileLanBoot, pThis->pu8LanBoot, cbFileLanBoot, NULL);
+                            AssertLogRelRCReturnStmt(rc, RTFileClose(hFileLanBoot), rc);
+                        }
+                        else
+                            rc = VERR_NO_MEMORY;
+                    }
+                    else
+                        rc = VERR_TOO_MUCH_DATA;
+                }
+                RTFileClose(hFileLanBoot);
+            }
+            if (RT_FAILURE(rc))
+            {
+                /*
+                 * Play stupid and ignore failures, falling back to the built-in LAN boot ROM.
+                 */
+                /** @todo r=bird: This should have some kind of rational. We don't usually
+                 *        ignore the VM configuration.  */
+                LogRel(("PcBios: Failed to open LAN boot ROM file '%s', rc=%Rrc!\n", pThis->pszLanBootFile, rc));
+                PDMDevHlpMMHeapFree(pDevIns, pThis->pszLanBootFile);
+                pThis->pszLanBootFile = NULL;
+            }
+        }
+
+        /* If we were unable to get the data from file for whatever reason, fall
+         * back to the built-in LAN boot ROM image.
+         */
+        if (pThis->pu8LanBoot == NULL)
+        {
+#ifdef VBOX_WITH_PXE_ROM
+            pu8LanBootBinary = g_abNetBiosBinary;
+            cbLanBootBinary  = g_cbNetBiosBinary;
+#endif
+        }
+        else
+        {
+            pu8LanBootBinary = pThis->pu8LanBoot;
+            cbLanBootBinary  = cbFileLanBoot;
+        }
+
+        /*
+         * Map the Network Boot ROM into memory.
+         *
+         * Currently there is a fixed mapping: 0x000e2000 to 0x000effff contains
+         * the (up to) 56 kb ROM image.  The mapping size is fixed to trouble with
+         * the saved state (in PGM).
+         */
+        if (pu8LanBootBinary)
+        {
+            pThis->cbLanBoot = cbLanBootBinary;
+
+            rc = PDMDevHlpROMRegister(pDevIns, VBOX_LANBOOT_SEG << 4,
+                                      RT_MAX(cbLanBootBinary, _64K - (VBOX_LANBOOT_SEG << 4 & 0xffff)),
+                                      pu8LanBootBinary, cbLanBootBinary,
+                                      PGMPHYS_ROM_FLAGS_SHADOWED, "Net Boot ROM");
+            AssertRCReturn(rc, rc);
+        }
+    }
+    else if (pThis->pszLanBootFile)
+        LogRel(("PcBios: Skipping LAN ROM '%s' due to ancient target CPU.\n", pThis->pszLanBootFile));
+#ifdef VBOX_WITH_PXE_ROM
+    else
+        LogRel(("PcBios: Skipping built in ROM due to ancient target CPU.\n"));
+#endif
+
+    /*
+     * Configure Boot delay.
+     */
+    rc = pHlp->pfnCFGMQueryU8Def(pCfg, "DelayBoot", &pThis->uBootDelay, 0);
+    if (RT_FAILURE(rc))
+        return PDMDEV_SET_ERROR(pDevIns, rc,
+                                    N_("Configuration error: Querying \"DelayBoot\" as integer failed"));
+    if (pThis->uBootDelay > 15)
+        pThis->uBootDelay = 15;
+
+
+    /*
+     * Read shutdown status code config and register ourselves as the firmware device.
+     */
+
+    /** @cfgm{CheckShutdownStatusForSoftReset, boolean, true}
+     * Whether to consult the shutdown status code (CMOS register 0Fh) to
+     * determine whether the guest intended a soft or hard reset.  Currently only
+     * shutdown status codes 05h, 09h and 0Ah are considered soft reset. */
+    rc = pHlp->pfnCFGMQueryBoolDef(pCfg, "CheckShutdownStatusForSoftReset", &pThis->fCheckShutdownStatusForSoftReset, true);
+    AssertLogRelRCReturn(rc, rc);
+
+    /** @cfgm{ClearShutdownStatusOnHardReset, boolean, true}
+     * Whether to clear the shutdown status code (CMOS register 0Fh) on hard reset. */
+    rc = pHlp->pfnCFGMQueryBoolDef(pCfg, "ClearShutdownStatusOnHardReset", &pThis->fClearShutdownStatusOnHardReset, true);
+    AssertLogRelRCReturn(rc, rc);
+
+    LogRel(("PcBios: fCheckShutdownStatusForSoftReset=%RTbool  fClearShutdownStatusOnHardReset=%RTbool\n",
+            pThis->fCheckShutdownStatusForSoftReset, pThis->fClearShutdownStatusOnHardReset));
+
+    static PDMFWREG const s_FwReg = { PDM_FWREG_VERSION, pcbiosFw_IsHardReset, PDM_FWREG_VERSION };
+    rc = PDMDevHlpFirmwareRegister(pDevIns, &s_FwReg, &pThis->pFwHlpR3);
+    AssertLogRelRCReturn(rc, rc);
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * The device registration structure.
+ */
+const PDMDEVREG g_DevicePcBios =
+{
+    /* .u32Version = */             PDM_DEVREG_VERSION,
+    /* .uReserved0 = */             0,
+    /* .szName = */                 "pcbios",
+    /* .fFlags = */                 PDM_DEVREG_FLAGS_DEFAULT_BITS | PDM_DEVREG_FLAGS_NEW_STYLE,
+    /* .fClass = */                 PDM_DEVREG_CLASS_ARCH_BIOS,
+    /* .cMaxInstances = */          1,
+    /* .uSharedVersion = */         42,
+    /* .cbInstanceShared = */       sizeof(DEVPCBIOS),
+    /* .cbInstanceCC = */           0,
+    /* .cbInstanceRC = */           0,
+    /* .cMaxPciDevices = */         0,
+    /* .cMaxMsixVectors = */        0,
+    /* .pszDescription = */         "PC BIOS Device",
+#if defined(IN_RING3)
+    /* .pszRCMod = */               "",
+    /* .pszR0Mod = */               "",
+    /* .pfnConstruct = */           pcbiosConstruct,
+    /* .pfnDestruct = */            pcbiosDestruct,
+    /* .pfnRelocate = */            NULL,
+    /* .pfnMemSetup = */            pcbiosMemSetup,
+    /* .pfnPowerOn = */             NULL,
+    /* .pfnReset = */               pcbiosReset,
+    /* .pfnSuspend = */             NULL,
+    /* .pfnResume = */              NULL,
+    /* .pfnAttach = */              NULL,
+    /* .pfnDetach = */              NULL,
+    /* .pfnQueryInterface = */      NULL,
+    /* .pfnInitComplete = */        pcbiosInitComplete,
+    /* .pfnPowerOff = */            NULL,
+    /* .pfnSoftReset = */           NULL,
+    /* .pfnReserved0 = */           NULL,
+    /* .pfnReserved1 = */           NULL,
+    /* .pfnReserved2 = */           NULL,
+    /* .pfnReserved3 = */           NULL,
+    /* .pfnReserved4 = */           NULL,
+    /* .pfnReserved5 = */           NULL,
+    /* .pfnReserved6 = */           NULL,
+    /* .pfnReserved7 = */           NULL,
+#elif defined(IN_RING0)
+    /* .pfnEarlyConstruct = */      NULL,
+    /* .pfnConstruct = */           NULL,
+    /* .pfnDestruct = */            NULL,
+    /* .pfnFinalDestruct = */       NULL,
+    /* .pfnRequest = */             NULL,
+    /* .pfnReserved0 = */           NULL,
+    /* .pfnReserved1 = */           NULL,
+    /* .pfnReserved2 = */           NULL,
+    /* .pfnReserved3 = */           NULL,
+    /* .pfnReserved4 = */           NULL,
+    /* .pfnReserved5 = */           NULL,
+    /* .pfnReserved6 = */           NULL,
+    /* .pfnReserved7 = */           NULL,
+#elif defined(IN_RC)
+    /* .pfnConstruct = */           NULL,
+    /* .pfnReserved0 = */           NULL,
+    /* .pfnReserved1 = */           NULL,
+    /* .pfnReserved2 = */           NULL,
+    /* .pfnReserved3 = */           NULL,
+    /* .pfnReserved4 = */           NULL,
+    /* .pfnReserved5 = */           NULL,
+    /* .pfnReserved6 = */           NULL,
+    /* .pfnReserved7 = */           NULL,
+#else
+# error "Not in IN_RING3, IN_RING0 or IN_RC!"
+#endif
+    /* .u32VersionEnd = */          PDM_DEVREG_VERSION
+};
+