Adding upstream version 6.1.22-dfsg.upstream/6.1.22-dfsgupstream

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

1 files changed, 2692 insertions, 0 deletions

diff --git a/src/VBox/VMM/VMMRZ/PGMRZDynMap.cpp b/src/VBox/VMM/VMMRZ/PGMRZDynMap.cpp
new file mode 100644
index 00000000..0f4313bb
--- /dev/null
+++ b/src/VBox/VMM/VMMRZ/PGMRZDynMap.cpp
@@ -0,0 +1,2692 @@
+/* $Id: PGMRZDynMap.cpp $ */
+/** @file
+ * PGM - Page Manager and Monitor, dynamic mapping cache.
+ */
+
+/*
+ * Copyright (C) 2008-2020 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.
+ */
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+#define LOG_GROUP LOG_GROUP_PGM_DYNMAP
+#include <VBox/vmm/pgm.h>
+#include "PGMInternal.h"
+#include <VBox/vmm/vm.h>
+#include "PGMInline.h"
+#include <VBox/err.h>
+#include <VBox/param.h>
+#include <VBox/sup.h>
+#include <iprt/asm.h>
+#include <iprt/asm-amd64-x86.h>
+#include <iprt/assert.h>
+#ifndef IN_RC
+# include <iprt/cpuset.h>
+# include <iprt/mem.h>
+# include <iprt/memobj.h>
+# include <iprt/mp.h>
+# include <iprt/semaphore.h>
+# include <iprt/spinlock.h>
+#endif
+#include <iprt/string.h>
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+#ifdef IN_RING0
+/** The max size of the mapping cache (in pages). */
+# define PGMR0DYNMAP_MAX_PAGES              ((16*_1M) >> PAGE_SHIFT)
+/** The small segment size that is adopted on out-of-memory conditions with a
+ * single big segment. */
+# define PGMR0DYNMAP_SMALL_SEG_PAGES        128
+/** The number of pages we reserve per CPU. */
+# define PGMR0DYNMAP_PAGES_PER_CPU          256
+/** The minimum number of pages we reserve per CPU.
+ * This must be equal or larger than the autoset size. */
+# define PGMR0DYNMAP_PAGES_PER_CPU_MIN      64
+/** Calcs the overload threshold (safety margin).  Current set at 50%. */
+# define PGMR0DYNMAP_CALC_OVERLOAD(cPages)  ((cPages) / 2)
+/** The number of guard pages.
+ * @remarks Never do tuning of the hashing or whatnot with a strict build! */
+# if defined(VBOX_STRICT)
+#  define PGMR0DYNMAP_GUARD_PAGES           1
+# else
+#  define PGMR0DYNMAP_GUARD_PAGES           0
+# endif
+#endif /* IN_RING0 */
+/** The dummy physical address of guard pages. */
+#define PGMR0DYNMAP_GUARD_PAGE_HCPHYS       UINT32_C(0x7777feed)
+/** The dummy reference count of guard pages. (Must be non-zero.) */
+#define PGMR0DYNMAP_GUARD_PAGE_REF_COUNT    INT32_C(0x7777feed)
+#if 0
+/** Define this to just clear the present bit on guard pages.
+ * The alternative is to replace the entire PTE with an bad not-present
+ * PTE. Either way, XNU will screw us. :-/ */
+# define PGMR0DYNMAP_GUARD_NP
+#endif
+/** The dummy PTE value for a page. */
+#define PGMR0DYNMAP_GUARD_PAGE_LEGACY_PTE   X86_PTE_PG_MASK
+/** The dummy PTE value for a page. */
+#define PGMR0DYNMAP_GUARD_PAGE_PAE_PTE      UINT64_MAX /*X86_PTE_PAE_PG_MASK*/
+
+#ifdef IN_RING0 /* Note! Assertions causes panics if preemption is disabled,
+                 *       disable this to work around that. */
+/**
+ * Acquire the spinlock.
+ * This will declare a temporary variable and expands to two statements!
+ */
+# define PGMRZDYNMAP_SPINLOCK_ACQUIRE(pThis) \
+    RTSpinlockAcquire((pThis)->hSpinlock)
+
+/**
+ * Releases the spinlock.
+ */
+# define PGMRZDYNMAP_SPINLOCK_RELEASE(pThis) \
+    RTSpinlockRelease((pThis)->hSpinlock)
+
+/**
+ * Re-acquires the spinlock.
+ */
+# define PGMRZDYNMAP_SPINLOCK_REACQUIRE(pThis) \
+    RTSpinlockAcquire((pThis)->hSpinlock)
+#else
+# define PGMRZDYNMAP_SPINLOCK_ACQUIRE(pThis)   do { } while (0)
+# define PGMRZDYNMAP_SPINLOCK_RELEASE(pThis)   do { } while (0)
+# define PGMRZDYNMAP_SPINLOCK_REACQUIRE(pThis) do { } while (0)
+#endif
+
+
+/** Converts a PGMCPUM::AutoSet pointer into a PVMCPU. */
+#define PGMRZDYNMAP_SET_2_VMCPU(pSet)       (RT_FROM_MEMBER(pSet, VMCPU, pgm.s.AutoSet))
+
+/** Converts a PGMCPUM::AutoSet pointer into a PVM. */
+#define PGMRZDYNMAP_SET_2_VM(pSet)          (PGMRZDYNMAP_SET_2_VMCPU(pSet)->CTX_SUFF(pVM))
+
+/** Converts a PGMCPUM::AutoSet pointer into a PVM. */
+#ifdef IN_RC
+# define PGMRZDYNMAP_SET_2_DYNMAP(pSet)     (PGMRZDYNMAP_SET_2_VM(pSet)->pgm.s.pRCDynMap)
+#else
+# define PGMRZDYNMAP_SET_2_DYNMAP(pSet)     (g_pPGMR0DynMap)
+#endif
+
+/**
+ * Gets the set index of the current CPU.
+ *
+ * This always returns 0 when in raw-mode context because there is only ever
+ * one EMT in that context (at least presently).
+ */
+#ifdef IN_RC
+# define PGMRZDYNMAP_CUR_CPU()              (0)
+#else
+# define PGMRZDYNMAP_CUR_CPU()              RTMpCurSetIndex()
+#endif
+
+/** PGMRZDYNMAP::u32Magic. (Jens Christian Bugge Wesseltoft) */
+#define PGMRZDYNMAP_MAGIC                   UINT32_C(0x19640201)
+
+
+/** Zaps an set entry. */
+#define PGMRZDYNMAP_ZAP_ENTRY(pEntry) \
+    do \
+    { \
+        (pEntry)->iPage        = UINT16_MAX; \
+        (pEntry)->cRefs        = 0; \
+        (pEntry)->cInlinedRefs = 0; \
+        (pEntry)->cUnrefs      = 0; \
+    } while (0)
+
+
+/** @def PGMRZDYNMAP_STRICT_RELEASE
+ * Define this to force pages to be released and make non-present ASAP after
+ * use.  This should not normally be enabled as it is a bit expensive. */
+#if 0 || defined(DOXYGEN_RUNNING)
+# define PGMRZDYNMAP_STRICT_RELEASE
+#endif
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+#ifdef IN_RING0
+/**
+ * Ring-0 dynamic mapping cache segment.
+ *
+ * The dynamic mapping cache can be extended with additional segments if the
+ * load is found to be too high.  This done the next time a VM is created, under
+ * the protection of the init mutex.  The arrays is reallocated and the new
+ * segment is added to the end of these.  Nothing is rehashed of course, as the
+ * indexes / addresses must remain unchanged.
+ *
+ * This structure is only modified while owning the init mutex or during module
+ * init / term.
+ */
+typedef struct PGMR0DYNMAPSEG
+{
+    /** Pointer to the next segment. */
+    struct PGMR0DYNMAPSEG      *pNext;
+    /** The memory object for the virtual address range that we're abusing. */
+    RTR0MEMOBJ                  hMemObj;
+    /** The start page in the cache. (I.e. index into the arrays.) */
+    uint16_t                    iPage;
+    /** The number of pages this segment contributes. */
+    uint16_t                    cPages;
+    /** The number of page tables. */
+    uint16_t                    cPTs;
+    /** The memory objects for the page tables. */
+    RTR0MEMOBJ                  ahMemObjPTs[1];
+} PGMR0DYNMAPSEG;
+/** Pointer to a ring-0 dynamic mapping cache segment. */
+typedef PGMR0DYNMAPSEG *PPGMR0DYNMAPSEG;
+
+
+/**
+ * Ring-0 dynamic mapping cache entry.
+ *
+ * @sa PGMRZDYNMAPENTRY, PGMRCDYNMAPENTRY.
+ */
+typedef struct PGMR0DYNMAPENTRY
+{
+    /** The physical address of the currently mapped page.
+     * This is duplicate for three reasons: cache locality, cache policy of the PT
+     * mappings and sanity checks. */
+    RTHCPHYS                    HCPhys;
+    /** Pointer to the page. */
+    void                       *pvPage;
+    /** The number of references. */
+    int32_t volatile            cRefs;
+    /** PTE pointer union. */
+    union PGMR0DYNMAPENTRY_PPTE
+    {
+        /** PTE pointer, 32-bit legacy version. */
+        PX86PTE                 pLegacy;
+        /** PTE pointer, PAE version. */
+        PX86PTEPAE              pPae;
+        /** PTE pointer, the void version. */
+        void                   *pv;
+    } uPte;
+    /** CPUs that haven't invalidated this entry after it's last update. */
+    RTCPUSET                    PendingSet;
+} PGMR0DYNMAPENTRY;
+/** Pointer a mapping cache entry for the ring-0.
+ * @sa PPGMRZDYNMAPENTRY, PPGMRCDYNMAPENTRY, */
+typedef PGMR0DYNMAPENTRY *PPGMR0DYNMAPENTRY;
+
+
+/**
+ * Dynamic mapping cache for ring-0.
+ *
+ * This is initialized during VMMR0 module init but no segments are allocated
+ * at that time.  Segments will be added when the first VM is started and
+ * removed again when the last VM shuts down, thus avoid consuming memory while
+ * dormant. At module termination, the remaining bits will be freed up.
+ *
+ * @sa PPGMRZDYNMAP, PGMRCDYNMAP.
+ */
+typedef struct PGMR0DYNMAP
+{
+    /** The usual magic number / eye catcher (PGMRZDYNMAP_MAGIC). */
+    uint32_t                    u32Magic;
+    /** Spinlock serializing the normal operation of the cache. */
+    RTSPINLOCK                  hSpinlock;
+    /** Array for tracking and managing the pages. */
+    PPGMR0DYNMAPENTRY           paPages;
+    /** The cache size given as a number of pages. */
+    uint32_t                    cPages;
+    /** Whether it's 32-bit legacy or PAE/AMD64 paging mode. */
+    bool                        fLegacyMode;
+    /** The current load.
+     * This does not include guard pages. */
+    uint32_t                    cLoad;
+    /** The max load ever.
+     * This is maintained to trigger the adding of more mapping space. */
+    uint32_t                    cMaxLoad;
+    /** Initialization / termination lock. */
+    RTSEMFASTMUTEX              hInitLock;
+    /** The number of guard pages. */
+    uint32_t                    cGuardPages;
+    /** The number of users (protected by hInitLock). */
+    uint32_t                    cUsers;
+    /** Array containing a copy of the original page tables.
+     * The entries are either X86PTE or X86PTEPAE according to fLegacyMode. */
+    void                       *pvSavedPTEs;
+    /** List of segments. */
+    PPGMR0DYNMAPSEG             pSegHead;
+    /** The paging mode. */
+    SUPPAGINGMODE               enmPgMode;
+} PGMR0DYNMAP;
+
+
+/**
+ * Paging level data.
+ */
+typedef struct PGMR0DYNMAPPGLVL
+{
+    uint32_t            cLevels;    /**< The number of levels. */
+    struct
+    {
+        RTHCPHYS        HCPhys;     /**< The address of the page for the current level,
+                                     *  i.e. what hMemObj/hMapObj is currently mapping. */
+        RTHCPHYS        fPhysMask;  /**< Mask for extracting HCPhys from uEntry. */
+        RTR0MEMOBJ      hMemObj;    /**< Memory object for HCPhys, PAGE_SIZE. */
+        RTR0MEMOBJ      hMapObj;    /**< Mapping object for hMemObj. */
+        uint32_t        fPtrShift;  /**< The pointer shift count. */
+        uint64_t        fPtrMask;   /**< The mask to apply to the shifted pointer to get the table index. */
+        uint64_t        fAndMask;   /**< And mask to check entry flags. */
+        uint64_t        fResMask;   /**< The result from applying fAndMask. */
+        union
+        {
+            void        *pv;        /**< hMapObj address. */
+            PX86PGUINT   paLegacy;  /**< Legacy table view. */
+            PX86PGPAEUINT paPae;    /**< PAE/AMD64 table view. */
+        } u;
+    } a[4];
+} PGMR0DYNMAPPGLVL;
+/** Pointer to paging level data. */
+typedef PGMR0DYNMAPPGLVL *PPGMR0DYNMAPPGLVL;
+#endif
+
+/** Mapping cache entry for the current context.
+ * @sa PGMR0DYNMAPENTRY, PGMRCDYNMAPENTRY */
+typedef CTX_MID(PGM,DYNMAPENTRY) PGMRZDYNMAPENTRY;
+/** Pointer a mapping cache entry for the current context.
+ * @sa PGMR0DYNMAPENTRY, PGMRCDYNMAPENTRY */
+typedef PGMRZDYNMAPENTRY *PPGMRZDYNMAPENTRY;
+
+/** Pointer to the mapping cache instance for the current context.
+ * @sa PGMR0DYNMAP, PGMRCDYNMAP */
+typedef CTX_MID(PGM,DYNMAP) *PPGMRZDYNMAP;
+
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+#ifdef IN_RING0
+/** Pointer to the ring-0 dynamic mapping cache. */
+static PGMR0DYNMAP *g_pPGMR0DynMap;
+#endif
+/** For overflow testing. */
+static bool         g_fPGMR0DynMapTestRunning = false;
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+static void pgmRZDynMapReleasePage(PPGMRZDYNMAP pThis, uint32_t iPage, uint32_t cRefs);
+#ifdef IN_RING0
+static int  pgmR0DynMapSetup(PPGMRZDYNMAP pThis);
+static int  pgmR0DynMapExpand(PPGMRZDYNMAP pThis);
+static void pgmR0DynMapTearDown(PPGMRZDYNMAP pThis);
+#endif
+#if 0 /*def DEBUG*/
+static int  pgmR0DynMapTest(PVM pVM);
+#endif
+
+
+/**
+ * Initializes the auto mapping sets for a VM.
+ *
+ * @returns VINF_SUCCESS on success, VERR_PGM_DYNMAP_IPE on failure.
+ * @param   pVM         The cross context VM structure.
+ */
+static int pgmRZDynMapInitAutoSetsForVM(PVM pVM)
+{
+    VMCPUID idCpu = pVM->cCpus;
+    AssertReturn(idCpu > 0 && idCpu <= VMM_MAX_CPU_COUNT, VERR_PGM_DYNMAP_IPE);
+    while (idCpu-- > 0)
+    {
+        PPGMMAPSET pSet = &pVM->aCpus[idCpu].pgm.s.AutoSet;
+        uint32_t j = RT_ELEMENTS(pSet->aEntries);
+        while (j-- > 0)
+        {
+            pSet->aEntries[j].pvPage        = NULL;
+            pSet->aEntries[j].HCPhys        = NIL_RTHCPHYS;
+            PGMRZDYNMAP_ZAP_ENTRY(&pSet->aEntries[j]);
+        }
+        pSet->cEntries = PGMMAPSET_CLOSED;
+        pSet->iSubset = UINT32_MAX;
+        pSet->iCpu = -1;
+        memset(&pSet->aiHashTable[0], 0xff, sizeof(pSet->aiHashTable));
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+#ifdef IN_RING0
+
+/**
+ * Initializes the ring-0 dynamic mapping cache.
+ *
+ * @returns VBox status code.
+ */
+VMMR0DECL(int) PGMR0DynMapInit(void)
+{
+    Assert(!g_pPGMR0DynMap);
+
+    /*
+     * Create and initialize the cache instance.
+     */
+    PPGMRZDYNMAP pThis = (PPGMRZDYNMAP)RTMemAllocZ(sizeof(*pThis));
+    AssertLogRelReturn(pThis, VERR_NO_MEMORY);
+    int             rc = VINF_SUCCESS;
+    pThis->enmPgMode = SUPR0GetPagingMode();
+    switch (pThis->enmPgMode)
+    {
+        case SUPPAGINGMODE_32_BIT:
+        case SUPPAGINGMODE_32_BIT_GLOBAL:
+            pThis->fLegacyMode = false;
+            break;
+        case SUPPAGINGMODE_PAE:
+        case SUPPAGINGMODE_PAE_GLOBAL:
+        case SUPPAGINGMODE_PAE_NX:
+        case SUPPAGINGMODE_PAE_GLOBAL_NX:
+        case SUPPAGINGMODE_AMD64:
+        case SUPPAGINGMODE_AMD64_GLOBAL:
+        case SUPPAGINGMODE_AMD64_NX:
+        case SUPPAGINGMODE_AMD64_GLOBAL_NX:
+            pThis->fLegacyMode = false;
+            break;
+        default:
+            rc = VERR_PGM_DYNMAP_IPE;
+            break;
+    }
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTSemFastMutexCreate(&pThis->hInitLock);
+        if (RT_SUCCESS(rc))
+        {
+            rc = RTSpinlockCreate(&pThis->hSpinlock, RTSPINLOCK_FLAGS_INTERRUPT_UNSAFE, "PGMR0DynMap");
+            if (RT_SUCCESS(rc))
+            {
+                pThis->u32Magic = PGMRZDYNMAP_MAGIC;
+                g_pPGMR0DynMap = pThis;
+                return VINF_SUCCESS;
+            }
+            RTSemFastMutexDestroy(pThis->hInitLock);
+        }
+    }
+    RTMemFree(pThis);
+    return rc;
+}
+
+
+/**
+ * Terminates the ring-0 dynamic mapping cache.
+ */
+VMMR0DECL(void) PGMR0DynMapTerm(void)
+{
+    /*
+     * Destroy the cache.
+     *
+     * There is not supposed to be any races here, the loader should
+     * make sure about that. So, don't bother locking anything.
+     *
+     * The VM objects should all be destroyed by now, so there is no
+     * dangling users or anything like that to clean up. This routine
+     * is just a mirror image of PGMR0DynMapInit.
+     */
+    PPGMRZDYNMAP pThis = g_pPGMR0DynMap;
+    if (pThis)
+    {
+        AssertPtr(pThis);
+        g_pPGMR0DynMap = NULL;
+
+        /* This should *never* happen, but in case it does try not to leak memory. */
+        AssertLogRelMsg(!pThis->cUsers && !pThis->paPages && !pThis->pvSavedPTEs && !pThis->cPages,
+                        ("cUsers=%d paPages=%p pvSavedPTEs=%p cPages=%#x\n",
+                         pThis->cUsers, pThis->paPages, pThis->pvSavedPTEs, pThis->cPages));
+        if (pThis->paPages)
+            pgmR0DynMapTearDown(pThis);
+
+        /* Free the associated resources. */
+        RTSemFastMutexDestroy(pThis->hInitLock);
+        pThis->hInitLock = NIL_RTSEMFASTMUTEX;
+        RTSpinlockDestroy(pThis->hSpinlock);
+        pThis->hSpinlock = NIL_RTSPINLOCK;
+        pThis->u32Magic = UINT32_MAX;
+        RTMemFree(pThis);
+    }
+}
+
+
+/**
+ * Initializes the dynamic mapping cache for a new VM.
+ *
+ * @returns VBox status code.
+ * @param   pVM         The cross context VM structure.
+ */
+VMMR0DECL(int) PGMR0DynMapInitVM(PVM pVM)
+{
+    AssertMsgReturn(!pVM->pgm.s.pvR0DynMapUsed, ("%p (pThis=%p)\n", pVM->pgm.s.pvR0DynMapUsed, g_pPGMR0DynMap), VERR_WRONG_ORDER);
+
+    /*
+     * Initialize the auto sets.
+     */
+    int rc = pgmRZDynMapInitAutoSetsForVM(pVM);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Do we need the cache? Skip the last bit if we don't.
+     */
+    if (VM_IS_RAW_MODE_ENABLED(pVM))
+        return VINF_SUCCESS;
+
+    /*
+     * Reference and if necessary setup or expand the cache.
+     */
+    PPGMRZDYNMAP pThis = g_pPGMR0DynMap;
+    AssertPtrReturn(pThis, VERR_PGM_DYNMAP_IPE);
+    rc = RTSemFastMutexRequest(pThis->hInitLock);
+    AssertLogRelRCReturn(rc, rc);
+
+    pThis->cUsers++;
+    if (pThis->cUsers == 1)
+    {
+        rc = pgmR0DynMapSetup(pThis);
+#if 0 /*def DEBUG*/
+        if (RT_SUCCESS(rc))
+        {
+            rc = pgmR0DynMapTest(pVM);
+            if (RT_FAILURE(rc))
+                pgmR0DynMapTearDown(pThis);
+        }
+#endif
+    }
+    else if (pThis->cMaxLoad > PGMR0DYNMAP_CALC_OVERLOAD(pThis->cPages - pThis->cGuardPages))
+        rc = pgmR0DynMapExpand(pThis);
+    if (RT_SUCCESS(rc))
+        pVM->pgm.s.pvR0DynMapUsed = pThis;
+    else
+        pThis->cUsers--;
+
+    RTSemFastMutexRelease(pThis->hInitLock);
+    return rc;
+}
+
+
+/**
+ * Terminates the dynamic mapping cache usage for a VM.
+ *
+ * @param   pVM         The cross context VM structure.
+ */
+VMMR0DECL(void) PGMR0DynMapTermVM(PVM pVM)
+{
+    /*
+     * Return immediately if we're not using the cache.
+     */
+    if (!pVM->pgm.s.pvR0DynMapUsed)
+        return;
+
+    PPGMRZDYNMAP pThis = g_pPGMR0DynMap;
+    AssertPtrReturnVoid(pThis);
+
+    int rc = RTSemFastMutexRequest(pThis->hInitLock);
+    AssertLogRelRCReturnVoid(rc);
+
+    if (pVM->pgm.s.pvR0DynMapUsed == pThis)
+    {
+        pVM->pgm.s.pvR0DynMapUsed = NULL;
+
+#ifdef VBOX_STRICT
+        PGMR0DynMapAssertIntegrity();
+#endif
+
+        /*
+         * Clean up and check the auto sets.
+         */
+        VMCPUID idCpu = pVM->cCpus;
+        while (idCpu-- > 0)
+        {
+            PPGMMAPSET pSet = &pVM->aCpus[idCpu].pgm.s.AutoSet;
+            uint32_t j = pSet->cEntries;
+            if (j <= RT_ELEMENTS(pSet->aEntries))
+            {
+                /*
+                 * The set is open, close it.
+                 */
+                while (j-- > 0)
+                {
+                    int32_t  cRefs = pSet->aEntries[j].cRefs;
+                    uint32_t iPage = pSet->aEntries[j].iPage;
+                    LogRel(("PGMR0DynMapTermVM: %d dangling refs to %#x\n", cRefs, iPage));
+                    if (iPage < pThis->cPages && cRefs > 0)
+                        pgmRZDynMapReleasePage(pThis, iPage, cRefs);
+                    else
+                        AssertLogRelMsgFailed(("cRefs=%d iPage=%#x cPages=%u\n", cRefs, iPage, pThis->cPages));
+
+                    PGMRZDYNMAP_ZAP_ENTRY(&pSet->aEntries[j]);
+                }
+                pSet->cEntries = PGMMAPSET_CLOSED;
+                pSet->iSubset = UINT32_MAX;
+                pSet->iCpu = -1;
+            }
+            else
+                AssertMsg(j == PGMMAPSET_CLOSED, ("cEntries=%#x\n", j));
+
+            j = RT_ELEMENTS(pSet->aEntries);
+            while (j-- > 0)
+            {
+                Assert(pSet->aEntries[j].iPage == UINT16_MAX);
+                Assert(!pSet->aEntries[j].cRefs);
+            }
+        }
+
+        /*
+         * Release our reference to the mapping cache.
+         */
+        Assert(pThis->cUsers > 0);
+        pThis->cUsers--;
+        if (!pThis->cUsers)
+            pgmR0DynMapTearDown(pThis);
+    }
+    else
+        AssertLogRelMsgFailed(("pvR0DynMapUsed=%p pThis=%p\n", pVM->pgm.s.pvR0DynMapUsed, pThis));
+
+    RTSemFastMutexRelease(pThis->hInitLock);
+}
+
+
+/**
+ * Shoots down the TLBs for all the cache pages, pgmR0DynMapTearDown helper.
+ *
+ * @param   idCpu           The current CPU.
+ * @param   pvUser1         The dynamic mapping cache instance.
+ * @param   pvUser2         Unused, NULL.
+ */
+static DECLCALLBACK(void) pgmR0DynMapShootDownTlbs(RTCPUID idCpu, void *pvUser1, void *pvUser2)
+{
+    Assert(!pvUser2);
+    PPGMRZDYNMAP        pThis   = (PPGMRZDYNMAP)pvUser1;
+    Assert(pThis == g_pPGMR0DynMap);
+    PPGMRZDYNMAPENTRY   paPages = pThis->paPages;
+    uint32_t            iPage   = pThis->cPages;
+    while (iPage-- > 0)
+        ASMInvalidatePage((uintptr_t)paPages[iPage].pvPage);
+}
+
+
+/**
+ * Shoot down the TLBs for every single cache entry on all CPUs.
+ *
+ * @returns IPRT status code (RTMpOnAll).
+ * @param   pThis       The dynamic mapping cache instance.
+ */
+static int pgmR0DynMapTlbShootDown(PPGMRZDYNMAP pThis)
+{
+    int rc = RTMpOnAll(pgmR0DynMapShootDownTlbs, pThis, NULL);
+    AssertRC(rc);
+    if (RT_FAILURE(rc))
+    {
+        uint32_t iPage = pThis->cPages;
+        while (iPage-- > 0)
+            ASMInvalidatePage((uintptr_t)pThis->paPages[iPage].pvPage);
+    }
+    return rc;
+}
+
+
+/**
+ * Calculate the new cache size based on cMaxLoad statistics.
+ *
+ * @returns Number of pages.
+ * @param   pThis       The dynamic mapping cache instance.
+ * @param   pcMinPages  The minimal size in pages.
+ */
+static uint32_t pgmR0DynMapCalcNewSize(PPGMRZDYNMAP pThis, uint32_t *pcMinPages)
+{
+    Assert(pThis->cPages <= PGMR0DYNMAP_MAX_PAGES);
+
+    /* cCpus * PGMR0DYNMAP_PAGES_PER_CPU(_MIN). */
+    RTCPUID     cCpus     = RTMpGetCount();
+    AssertReturn(cCpus > 0 && cCpus <= RTCPUSET_MAX_CPUS, 0);
+    uint32_t    cPages    = cCpus * PGMR0DYNMAP_PAGES_PER_CPU;
+    uint32_t    cMinPages = cCpus * PGMR0DYNMAP_PAGES_PER_CPU_MIN;
+
+    /* adjust against cMaxLoad. */
+    AssertMsg(pThis->cMaxLoad <= PGMR0DYNMAP_MAX_PAGES, ("%#x\n", pThis->cMaxLoad));
+    if (pThis->cMaxLoad > PGMR0DYNMAP_MAX_PAGES)
+        pThis->cMaxLoad = 0;
+
+    while (pThis->cMaxLoad > PGMR0DYNMAP_CALC_OVERLOAD(cPages))
+        cPages += PGMR0DYNMAP_PAGES_PER_CPU;
+
+    if (pThis->cMaxLoad > cMinPages)
+        cMinPages = pThis->cMaxLoad;
+
+    /* adjust against max and current size. */
+    if (cPages < pThis->cPages)
+        cPages = pThis->cPages;
+    cPages *= PGMR0DYNMAP_GUARD_PAGES + 1;
+    if (cPages > PGMR0DYNMAP_MAX_PAGES)
+        cPages = PGMR0DYNMAP_MAX_PAGES;
+
+    if (cMinPages < pThis->cPages)
+        cMinPages = pThis->cPages;
+    cMinPages *= PGMR0DYNMAP_GUARD_PAGES + 1;
+    if (cMinPages > PGMR0DYNMAP_MAX_PAGES)
+        cMinPages = PGMR0DYNMAP_MAX_PAGES;
+
+    Assert(cMinPages);
+    *pcMinPages = cMinPages;
+    return cPages;
+}
+
+
+/**
+ * Initializes the paging level data.
+ *
+ * @param   pThis       The dynamic mapping cache instance.
+ * @param   pPgLvl      The paging level data.
+ */
+void pgmR0DynMapPagingArrayInit(PPGMRZDYNMAP pThis, PPGMR0DYNMAPPGLVL pPgLvl)
+{
+    RTCCUINTREG     cr4 = ASMGetCR4();
+    switch (pThis->enmPgMode)
+    {
+        case SUPPAGINGMODE_32_BIT:
+        case SUPPAGINGMODE_32_BIT_GLOBAL:
+            pPgLvl->cLevels = 2;
+            pPgLvl->a[0].fPhysMask = X86_CR3_PAGE_MASK;
+            pPgLvl->a[0].fAndMask  = X86_PDE_P | X86_PDE_RW | (cr4 & X86_CR4_PSE ? X86_PDE_PS : 0);
+            pPgLvl->a[0].fResMask  = X86_PDE_P | X86_PDE_RW;
+            pPgLvl->a[0].fPtrMask  = X86_PD_MASK;
+            pPgLvl->a[0].fPtrShift = X86_PD_SHIFT;
+
+            pPgLvl->a[1].fPhysMask = X86_PDE_PG_MASK;
+            pPgLvl->a[1].fAndMask  = X86_PTE_P | X86_PTE_RW;
+            pPgLvl->a[1].fResMask  = X86_PTE_P | X86_PTE_RW;
+            pPgLvl->a[1].fPtrMask  = X86_PT_MASK;
+            pPgLvl->a[1].fPtrShift = X86_PT_SHIFT;
+            break;
+
+        case SUPPAGINGMODE_PAE:
+        case SUPPAGINGMODE_PAE_GLOBAL:
+        case SUPPAGINGMODE_PAE_NX:
+        case SUPPAGINGMODE_PAE_GLOBAL_NX:
+            pPgLvl->cLevels = 3;
+            pPgLvl->a[0].fPhysMask = X86_CR3_PAE_PAGE_MASK;
+            pPgLvl->a[0].fPtrMask  = X86_PDPT_MASK_PAE;
+            pPgLvl->a[0].fPtrShift = X86_PDPT_SHIFT;
+            pPgLvl->a[0].fAndMask  = X86_PDPE_P;
+            pPgLvl->a[0].fResMask  = X86_PDPE_P;
+
+            pPgLvl->a[1].fPhysMask = X86_PDPE_PG_MASK;
+            pPgLvl->a[1].fPtrMask  = X86_PD_PAE_MASK;
+            pPgLvl->a[1].fPtrShift = X86_PD_PAE_SHIFT;
+            pPgLvl->a[1].fAndMask  = X86_PDE_P | X86_PDE_RW | (cr4 & X86_CR4_PSE ? X86_PDE_PS : 0);
+            pPgLvl->a[1].fResMask  = X86_PDE_P | X86_PDE_RW;
+
+            pPgLvl->a[2].fPhysMask = X86_PDE_PAE_PG_MASK;
+            pPgLvl->a[2].fPtrMask  = X86_PT_PAE_MASK;
+            pPgLvl->a[2].fPtrShift = X86_PT_PAE_SHIFT;
+            pPgLvl->a[2].fAndMask  = X86_PTE_P | X86_PTE_RW;
+            pPgLvl->a[2].fResMask  = X86_PTE_P | X86_PTE_RW;
+            break;
+
+        case SUPPAGINGMODE_AMD64:
+        case SUPPAGINGMODE_AMD64_GLOBAL:
+        case SUPPAGINGMODE_AMD64_NX:
+        case SUPPAGINGMODE_AMD64_GLOBAL_NX:
+            pPgLvl->cLevels = 4;
+            pPgLvl->a[0].fPhysMask = X86_CR3_AMD64_PAGE_MASK;
+            pPgLvl->a[0].fPtrShift = X86_PML4_SHIFT;
+            pPgLvl->a[0].fPtrMask  = X86_PML4_MASK;
+            pPgLvl->a[0].fAndMask  = X86_PML4E_P | X86_PML4E_RW;
+            pPgLvl->a[0].fResMask  = X86_PML4E_P | X86_PML4E_RW;
+
+            pPgLvl->a[1].fPhysMask = X86_PML4E_PG_MASK;
+            pPgLvl->a[1].fPtrShift = X86_PDPT_SHIFT;
+            pPgLvl->a[1].fPtrMask  = X86_PDPT_MASK_AMD64;
+            pPgLvl->a[1].fAndMask  = X86_PDPE_P | X86_PDPE_RW /** @todo check for X86_PDPT_PS support. */;
+            pPgLvl->a[1].fResMask  = X86_PDPE_P | X86_PDPE_RW;
+
+            pPgLvl->a[2].fPhysMask = X86_PDPE_PG_MASK;
+            pPgLvl->a[2].fPtrShift = X86_PD_PAE_SHIFT;
+            pPgLvl->a[2].fPtrMask  = X86_PD_PAE_MASK;
+            pPgLvl->a[2].fAndMask  = X86_PDE_P | X86_PDE_RW | (cr4 & X86_CR4_PSE ? X86_PDE_PS : 0);
+            pPgLvl->a[2].fResMask  = X86_PDE_P | X86_PDE_RW;
+
+            pPgLvl->a[3].fPhysMask = X86_PDE_PAE_PG_MASK;
+            pPgLvl->a[3].fPtrShift = X86_PT_PAE_SHIFT;
+            pPgLvl->a[3].fPtrMask  = X86_PT_PAE_MASK;
+            pPgLvl->a[3].fAndMask  = X86_PTE_P | X86_PTE_RW;
+            pPgLvl->a[3].fResMask  = X86_PTE_P | X86_PTE_RW;
+            break;
+
+        default:
+            AssertFailed();
+            pPgLvl->cLevels = 0;
+            break;
+    }
+
+    for (uint32_t i = 0; i < 4; i++) /* ASSUMING array size. */
+    {
+        pPgLvl->a[i].HCPhys = NIL_RTHCPHYS;
+        pPgLvl->a[i].hMapObj = NIL_RTR0MEMOBJ;
+        pPgLvl->a[i].hMemObj = NIL_RTR0MEMOBJ;
+        pPgLvl->a[i].u.pv = NULL;
+    }
+}
+
+
+/**
+ * Maps a PTE.
+ *
+ * This will update the segment structure when new PTs are mapped.
+ *
+ * It also assumes that we (for paranoid reasons) wish to establish a mapping
+ * chain from CR3 to the PT that all corresponds to the processor we're
+ * currently running on, and go about this by running with interrupts disabled
+ * and restarting from CR3 for every change.
+ *
+ * @returns VBox status code, VINF_TRY_AGAIN if we changed any mappings and had
+ *          to re-enable interrupts.
+ * @param   pThis       The dynamic mapping cache instance.
+ * @param   pPgLvl      The paging level structure.
+ * @param   pvPage      The page.
+ * @param   pSeg        The segment.
+ * @param   cMaxPTs     The max number of PTs expected in the segment.
+ * @param   ppvPTE      Where to store the PTE address.
+ */
+static int pgmR0DynMapPagingArrayMapPte(PPGMRZDYNMAP pThis, PPGMR0DYNMAPPGLVL pPgLvl, void *pvPage,
+                                        PPGMR0DYNMAPSEG pSeg, uint32_t cMaxPTs, void **ppvPTE)
+{
+    Assert(!(ASMGetFlags() & X86_EFL_IF));
+    void           *pvEntry = NULL;
+    X86PGPAEUINT    uEntry = ASMGetCR3();
+    for (uint32_t i = 0; i < pPgLvl->cLevels; i++)
+    {
+        RTHCPHYS HCPhys = uEntry & pPgLvl->a[i].fPhysMask;
+        if (pPgLvl->a[i].HCPhys != HCPhys)
+        {
+            /*
+             * Need to remap this level.
+             * The final level, the PT, will not be freed since that is what it's all about.
+             */
+            ASMIntEnable();
+            if (i + 1 == pPgLvl->cLevels)
+                AssertReturn(pSeg->cPTs < cMaxPTs, VERR_PGM_DYNMAP_IPE);
+            else
+            {
+                int rc2 = RTR0MemObjFree(pPgLvl->a[i].hMemObj, true /* fFreeMappings */); AssertRC(rc2);
+                pPgLvl->a[i].hMemObj = pPgLvl->a[i].hMapObj = NIL_RTR0MEMOBJ;
+            }
+
+            int rc = RTR0MemObjEnterPhys(&pPgLvl->a[i].hMemObj, HCPhys, PAGE_SIZE, RTMEM_CACHE_POLICY_DONT_CARE);
+            if (RT_SUCCESS(rc))
+            {
+                rc = RTR0MemObjMapKernel(&pPgLvl->a[i].hMapObj, pPgLvl->a[i].hMemObj,
+                                         (void *)-1 /* pvFixed */, 0 /* cbAlignment */,
+                                         RTMEM_PROT_WRITE | RTMEM_PROT_READ);
+                if (RT_SUCCESS(rc))
+                {
+                    pPgLvl->a[i].u.pv   = RTR0MemObjAddress(pPgLvl->a[i].hMapObj);
+                    AssertMsg(((uintptr_t)pPgLvl->a[i].u.pv & ~(uintptr_t)PAGE_OFFSET_MASK), ("%p\n", pPgLvl->a[i].u.pv));
+                    pPgLvl->a[i].HCPhys = HCPhys;
+                    if (i + 1 == pPgLvl->cLevels)
+                        pSeg->ahMemObjPTs[pSeg->cPTs++] = pPgLvl->a[i].hMemObj;
+                    ASMIntDisable();
+                    return VINF_TRY_AGAIN;
+                }
+
+                pPgLvl->a[i].hMapObj = NIL_RTR0MEMOBJ;
+            }
+            else
+                pPgLvl->a[i].hMemObj = NIL_RTR0MEMOBJ;
+            pPgLvl->a[i].HCPhys = NIL_RTHCPHYS;
+            return rc;
+        }
+
+        /*
+         * The next level.
+         */
+        uint32_t iEntry = ((uint64_t)(uintptr_t)pvPage >> pPgLvl->a[i].fPtrShift) & pPgLvl->a[i].fPtrMask;
+        if (pThis->fLegacyMode)
+        {
+            pvEntry = &pPgLvl->a[i].u.paLegacy[iEntry];
+            uEntry  = pPgLvl->a[i].u.paLegacy[iEntry];
+        }
+        else
+        {
+            pvEntry = &pPgLvl->a[i].u.paPae[iEntry];
+            uEntry  = pPgLvl->a[i].u.paPae[iEntry];
+        }
+
+        if ((uEntry & pPgLvl->a[i].fAndMask) != pPgLvl->a[i].fResMask)
+        {
+            LogRel(("PGMR0DynMap: internal error - iPgLvl=%u cLevels=%u uEntry=%#llx fAnd=%#llx fRes=%#llx got=%#llx\n"
+                    "PGMR0DynMap: pv=%p pvPage=%p iEntry=%#x fLegacyMode=%RTbool\n",
+                    i, pPgLvl->cLevels, uEntry, pPgLvl->a[i].fAndMask, pPgLvl->a[i].fResMask, uEntry & pPgLvl->a[i].fAndMask,
+                    pPgLvl->a[i].u.pv, pvPage, iEntry, pThis->fLegacyMode));
+            return VERR_PGM_DYNMAP_IPE;
+        }
+        /*Log(("#%d: iEntry=%4d uEntry=%#llx pvEntry=%p HCPhys=%RHp \n", i, iEntry, uEntry, pvEntry, pPgLvl->a[i].HCPhys));*/
+    }
+
+    /* made it thru without needing to remap anything. */
+    *ppvPTE = pvEntry;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Sets up a guard page.
+ *
+ * @param   pThis       The dynamic mapping cache instance.
+ * @param   pPage       The page.
+ */
+DECLINLINE(void) pgmR0DynMapSetupGuardPage(PPGMRZDYNMAP pThis, PPGMRZDYNMAPENTRY pPage)
+{
+    memset(pPage->pvPage, 0xfd, PAGE_SIZE);
+    pPage->cRefs  = PGMR0DYNMAP_GUARD_PAGE_REF_COUNT;
+    pPage->HCPhys = PGMR0DYNMAP_GUARD_PAGE_HCPHYS;
+#ifdef PGMR0DYNMAP_GUARD_NP
+    ASMAtomicBitClear(pPage->uPte.pv, X86_PTE_BIT_P);
+#else
+    if (pThis->fLegacyMode)
+        ASMAtomicWriteU32(&pPage->uPte.pLegacy->u, PGMR0DYNMAP_GUARD_PAGE_LEGACY_PTE);
+    else
+        ASMAtomicWriteU64(&pPage->uPte.pPae->u,    PGMR0DYNMAP_GUARD_PAGE_PAE_PTE);
+#endif
+    pThis->cGuardPages++;
+}
+
+
+/**
+ * Adds a new segment of the specified size.
+ *
+ * @returns VBox status code.
+ * @param   pThis       The dynamic mapping cache instance.
+ * @param   cPages      The size of the new segment, give as a page count.
+ */
+static int pgmR0DynMapAddSeg(PPGMRZDYNMAP pThis, uint32_t cPages)
+{
+    int rc2;
+    AssertReturn(ASMGetFlags() & X86_EFL_IF, VERR_PREEMPT_DISABLED);
+
+    /*
+     * Do the array reallocations first.
+     * (The pages array has to be replaced behind the spinlock of course.)
+     */
+    void *pvSavedPTEs = RTMemRealloc(pThis->pvSavedPTEs, (pThis->fLegacyMode ? sizeof(X86PGUINT) : sizeof(X86PGPAEUINT)) * (pThis->cPages + cPages));
+    if (!pvSavedPTEs)
+        return VERR_NO_MEMORY;
+    pThis->pvSavedPTEs = pvSavedPTEs;
+
+    void *pvPages = RTMemAllocZ(sizeof(pThis->paPages[0]) * (pThis->cPages + cPages));
+    if (!pvPages)
+    {
+        pvSavedPTEs = RTMemRealloc(pThis->pvSavedPTEs, (pThis->fLegacyMode ? sizeof(X86PGUINT) : sizeof(X86PGPAEUINT)) * pThis->cPages);
+        if (pvSavedPTEs)
+            pThis->pvSavedPTEs = pvSavedPTEs;
+        return VERR_NO_MEMORY;
+    }
+
+    PGMRZDYNMAP_SPINLOCK_ACQUIRE(pThis);
+
+    memcpy(pvPages, pThis->paPages, sizeof(pThis->paPages[0]) * pThis->cPages);
+    void *pvToFree = pThis->paPages;
+    pThis->paPages = (PPGMRZDYNMAPENTRY)pvPages;
+
+    PGMRZDYNMAP_SPINLOCK_RELEASE(pThis);
+    RTMemFree(pvToFree);
+
+    /*
+     * Allocate the segment structure and pages of memory, then touch all the pages (paranoia).
+     */
+    uint32_t cMaxPTs = cPages / (pThis->fLegacyMode ? X86_PG_ENTRIES : X86_PG_PAE_ENTRIES) + 2;
+    PPGMR0DYNMAPSEG pSeg = (PPGMR0DYNMAPSEG)RTMemAllocZ(RT_UOFFSETOF_DYN(PGMR0DYNMAPSEG, ahMemObjPTs[cMaxPTs]));
+    if (!pSeg)
+        return VERR_NO_MEMORY;
+    pSeg->pNext  = NULL;
+    pSeg->cPages = cPages;
+    pSeg->iPage  = pThis->cPages;
+    pSeg->cPTs   = 0;
+    int rc = RTR0MemObjAllocPage(&pSeg->hMemObj, cPages << PAGE_SHIFT, false);
+    if (RT_SUCCESS(rc))
+    {
+        uint8_t            *pbPage = (uint8_t *)RTR0MemObjAddress(pSeg->hMemObj);
+        AssertMsg(VALID_PTR(pbPage) && !((uintptr_t)pbPage & PAGE_OFFSET_MASK), ("%p\n", pbPage));
+        memset(pbPage, 0xfe, cPages << PAGE_SHIFT);
+
+        /*
+         * Walk thru the pages and set them up with a mapping of their PTE and everything.
+         */
+        ASMIntDisable();
+        PGMR0DYNMAPPGLVL    PgLvl;
+        pgmR0DynMapPagingArrayInit(pThis, &PgLvl);
+        uint32_t const      iEndPage = pSeg->iPage + cPages;
+        for (uint32_t iPage = pSeg->iPage;
+             iPage < iEndPage;
+             iPage++, pbPage += PAGE_SIZE)
+        {
+            /* Initialize the page data. */
+            pThis->paPages[iPage].HCPhys = NIL_RTHCPHYS;
+            pThis->paPages[iPage].pvPage = pbPage;
+            pThis->paPages[iPage].cRefs  = 0;
+            pThis->paPages[iPage].uPte.pPae = 0;
+#ifndef IN_RC
+            RTCpuSetFill(&pThis->paPages[iPage].PendingSet);
+#endif
+
+            /* Map its page table, retry until we've got a clean run (paranoia). */
+            do
+                rc = pgmR0DynMapPagingArrayMapPte(pThis, &PgLvl, pbPage, pSeg, cMaxPTs,
+                                                  &pThis->paPages[iPage].uPte.pv);
+            while (rc == VINF_TRY_AGAIN);
+            if (RT_FAILURE(rc))
+                break;
+
+            /* Save the PTE. */
+            if (pThis->fLegacyMode)
+                ((PX86PGUINT)pThis->pvSavedPTEs)[iPage]    = pThis->paPages[iPage].uPte.pLegacy->u;
+            else
+                ((PX86PGPAEUINT)pThis->pvSavedPTEs)[iPage] = pThis->paPages[iPage].uPte.pPae->u;
+
+#ifdef VBOX_STRICT
+            /* Check that we've got the right entry. */
+            RTHCPHYS HCPhysPage = RTR0MemObjGetPagePhysAddr(pSeg->hMemObj, iPage - pSeg->iPage);
+            RTHCPHYS HCPhysPte  = pThis->fLegacyMode
+                                ? pThis->paPages[iPage].uPte.pLegacy->u & X86_PTE_PG_MASK
+                                : pThis->paPages[iPage].uPte.pPae->u    & X86_PTE_PAE_PG_MASK;
+            if (HCPhysPage != HCPhysPte)
+            {
+                LogRel(("pgmR0DynMapAddSeg: internal error - page #%u HCPhysPage=%RHp HCPhysPte=%RHp pbPage=%p pvPte=%p\n",
+                        iPage - pSeg->iPage, HCPhysPage, HCPhysPte, pbPage, pThis->paPages[iPage].uPte.pv));
+                rc = VERR_PGM_DYNMAP_IPE;
+                break;
+            }
+#endif
+        } /* for each page */
+        ASMIntEnable();
+
+        /* cleanup non-PT mappings */
+        for (uint32_t i = 0; i < PgLvl.cLevels - 1; i++)
+            RTR0MemObjFree(PgLvl.a[i].hMemObj, true /* fFreeMappings */);
+
+        if (RT_SUCCESS(rc))
+        {
+#if PGMR0DYNMAP_GUARD_PAGES > 0
+            /*
+             * Setup guard pages.
+             * (Note: TLBs will be shot down later on.)
+             */
+            uint32_t iPage = pSeg->iPage;
+            while (iPage < iEndPage)
+            {
+                for (uint32_t iGPg = 0; iGPg < PGMR0DYNMAP_GUARD_PAGES && iPage < iEndPage; iGPg++, iPage++)
+                    pgmR0DynMapSetupGuardPage(pThis, &pThis->paPages[iPage]);
+                iPage++; /* the guarded page */
+            }
+
+            /* Make sure the very last page is a guard page too. */
+            iPage = iEndPage - 1;
+            if (pThis->paPages[iPage].cRefs != PGMR0DYNMAP_GUARD_PAGE_REF_COUNT)
+                pgmR0DynMapSetupGuardPage(pThis, &pThis->paPages[iPage]);
+#endif /* PGMR0DYNMAP_GUARD_PAGES > 0 */
+
+            /*
+             * Commit it by adding the segment to the list and updating the page count.
+             */
+            pSeg->pNext = pThis->pSegHead;
+            pThis->pSegHead = pSeg;
+            pThis->cPages += cPages;
+            return VINF_SUCCESS;
+        }
+
+        /*
+         * Bail out.
+         */
+        while (pSeg->cPTs-- > 0)
+        {
+            rc2 = RTR0MemObjFree(pSeg->ahMemObjPTs[pSeg->cPTs], true /* fFreeMappings */);
+            AssertRC(rc2);
+            pSeg->ahMemObjPTs[pSeg->cPTs] = NIL_RTR0MEMOBJ;
+        }
+
+        rc2 = RTR0MemObjFree(pSeg->hMemObj, true /* fFreeMappings */);
+        AssertRC(rc2);
+        pSeg->hMemObj = NIL_RTR0MEMOBJ;
+    }
+    else if (rc == VERR_NO_PAGE_MEMORY || rc == VERR_NO_PHYS_MEMORY)
+        rc = VERR_NO_MEMORY;
+    RTMemFree(pSeg);
+
+    /* Don't bother resizing the arrays, but free them if we're the only user. */
+    if (!pThis->cPages)
+    {
+        RTMemFree(pThis->paPages);
+        pThis->paPages = NULL;
+        RTMemFree(pThis->pvSavedPTEs);
+        pThis->pvSavedPTEs = NULL;
+    }
+    return rc;
+}
+
+
+/**
+ * Called by PGMR0DynMapInitVM under the init lock.
+ *
+ * @returns VBox status code.
+ * @param   pThis       The dynamic mapping cache instance.
+ */
+static int pgmR0DynMapSetup(PPGMRZDYNMAP pThis)
+{
+    /*
+     * Calc the size and add a segment of that size.
+     */
+    uint32_t cMinPages;
+    uint32_t cPages = pgmR0DynMapCalcNewSize(pThis, &cMinPages);
+    AssertReturn(cPages, VERR_PGM_DYNMAP_IPE);
+    int rc = pgmR0DynMapAddSeg(pThis, cPages);
+    if (rc == VERR_NO_MEMORY)
+    {
+        /*
+         * Try adding smaller segments.
+         */
+        do
+            rc = pgmR0DynMapAddSeg(pThis, PGMR0DYNMAP_SMALL_SEG_PAGES);
+        while (RT_SUCCESS(rc) && pThis->cPages < cPages);
+        if (rc == VERR_NO_MEMORY && pThis->cPages >= cMinPages)
+            rc = VINF_SUCCESS;
+        if (rc == VERR_NO_MEMORY)
+        {
+            if (pThis->cPages)
+                pgmR0DynMapTearDown(pThis);
+            rc = VERR_PGM_DYNMAP_SETUP_ERROR;
+        }
+    }
+    Assert(ASMGetFlags() & X86_EFL_IF);
+
+#if PGMR0DYNMAP_GUARD_PAGES > 0
+    /* paranoia */
+    if (RT_SUCCESS(rc))
+        pgmR0DynMapTlbShootDown(pThis);
+#endif
+    return rc;
+}
+
+
+/**
+ * Called by PGMR0DynMapInitVM under the init lock.
+ *
+ * @returns VBox status code.
+ * @param   pThis       The dynamic mapping cache instance.
+ */
+static int pgmR0DynMapExpand(PPGMRZDYNMAP pThis)
+{
+    /*
+     * Calc the new target size and add a segment of the appropriate size.
+     */
+    uint32_t cMinPages;
+    uint32_t cPages = pgmR0DynMapCalcNewSize(pThis, &cMinPages);
+    AssertReturn(cPages, VERR_PGM_DYNMAP_IPE);
+    if (pThis->cPages >= cPages)
+        return VINF_SUCCESS;
+
+    uint32_t cAdd = cPages - pThis->cPages;
+    int rc = pgmR0DynMapAddSeg(pThis, cAdd);
+    if (rc == VERR_NO_MEMORY)
+    {
+        /*
+         * Try adding smaller segments.
+         */
+        do
+            rc = pgmR0DynMapAddSeg(pThis, PGMR0DYNMAP_SMALL_SEG_PAGES);
+        while (RT_SUCCESS(rc) && pThis->cPages < cPages);
+        if (rc == VERR_NO_MEMORY && pThis->cPages >= cMinPages)
+            rc = VINF_SUCCESS;
+        if (rc == VERR_NO_MEMORY)
+            rc = VERR_PGM_DYNMAP_EXPAND_ERROR;
+    }
+    Assert(ASMGetFlags() & X86_EFL_IF);
+
+#if PGMR0DYNMAP_GUARD_PAGES > 0
+    /* paranoia */
+    if (RT_SUCCESS(rc))
+        pgmR0DynMapTlbShootDown(pThis);
+#endif
+    return rc;
+}
+
+
+/**
+ * Called by PGMR0DynMapTermVM under the init lock.
+ *
+ * @returns VBox status code.
+ * @param   pThis       The dynamic mapping cache instance.
+ */
+static void pgmR0DynMapTearDown(PPGMRZDYNMAP pThis)
+{
+    /*
+     * Restore the original page table entries
+     */
+    PPGMRZDYNMAPENTRY   paPages = pThis->paPages;
+    uint32_t            iPage   = pThis->cPages;
+    if (pThis->fLegacyMode)
+    {
+        X86PGUINT const    *paSavedPTEs = (X86PGUINT const *)pThis->pvSavedPTEs;
+        while (iPage-- > 0)
+        {
+            X86PGUINT       uOld  = paPages[iPage].uPte.pLegacy->u;
+            X86PGUINT       uOld2 = uOld; NOREF(uOld2);
+            X86PGUINT       uNew  = paSavedPTEs[iPage];
+            while (!ASMAtomicCmpXchgExU32(&paPages[iPage].uPte.pLegacy->u, uNew, uOld, &uOld))
+                AssertMsgFailed(("uOld=%#x uOld2=%#x uNew=%#x\n", uOld, uOld2, uNew));
+            Assert(paPages[iPage].uPte.pLegacy->u == paSavedPTEs[iPage]);
+        }
+    }
+    else
+    {
+        X86PGPAEUINT const *paSavedPTEs = (X86PGPAEUINT const *)pThis->pvSavedPTEs;
+        while (iPage-- > 0)
+        {
+            X86PGPAEUINT    uOld  = paPages[iPage].uPte.pPae->u;
+            X86PGPAEUINT    uOld2 = uOld; NOREF(uOld2);
+            X86PGPAEUINT    uNew  = paSavedPTEs[iPage];
+            while (!ASMAtomicCmpXchgExU64(&paPages[iPage].uPte.pPae->u, uNew, uOld, &uOld))
+                AssertMsgFailed(("uOld=%#llx uOld2=%#llx uNew=%#llx\n", uOld, uOld2, uNew));
+            Assert(paPages[iPage].uPte.pPae->u == paSavedPTEs[iPage]);
+        }
+    }
+
+    /*
+     * Shoot down the TLBs on all CPUs before freeing them.
+     */
+    pgmR0DynMapTlbShootDown(pThis);
+
+    /*
+     * Free the segments.
+     */
+    while (pThis->pSegHead)
+    {
+        int             rc;
+        PPGMR0DYNMAPSEG pSeg = pThis->pSegHead;
+        pThis->pSegHead = pSeg->pNext;
+
+        uint32_t iPT = pSeg->cPTs;
+        while (iPT-- > 0)
+        {
+            rc = RTR0MemObjFree(pSeg->ahMemObjPTs[iPT], true /* fFreeMappings */); AssertRC(rc);
+            pSeg->ahMemObjPTs[iPT] = NIL_RTR0MEMOBJ;
+        }
+        rc = RTR0MemObjFree(pSeg->hMemObj, true /* fFreeMappings */); AssertRC(rc);
+        pSeg->hMemObj   = NIL_RTR0MEMOBJ;
+        pSeg->pNext     = NULL;
+        pSeg->iPage     = UINT16_MAX;
+        pSeg->cPages    = 0;
+        pSeg->cPTs      = 0;
+        RTMemFree(pSeg);
+    }
+
+    /*
+     * Free the arrays and restore the initial state.
+     * The cLoadMax value is left behind for the next setup.
+     */
+    RTMemFree(pThis->paPages);
+    pThis->paPages = NULL;
+    RTMemFree(pThis->pvSavedPTEs);
+    pThis->pvSavedPTEs = NULL;
+    pThis->cPages = 0;
+    pThis->cLoad = 0;
+    pThis->cGuardPages = 0;
+}
+
+#endif /* IN_RING0 */
+#ifdef IN_RC
+
+/**
+ * Initializes the dynamic mapping cache in raw-mode context.
+ *
+ * @returns VBox status code.
+ * @param   pVM                 The cross context VM structure.
+ */
+VMMRCDECL(int) PGMRCDynMapInit(PVM pVM)
+{
+    /*
+     * Allocate and initialize the instance data and page array.
+     */
+    PPGMRZDYNMAP    pThis;
+    size_t const    cPages = MM_HYPER_DYNAMIC_SIZE / PAGE_SIZE;
+    size_t const    cb     = RT_ALIGN_Z(sizeof(*pThis), 32)
+                           + sizeof(PGMRZDYNMAPENTRY) * cPages;
+    int rc = MMHyperAlloc(pVM, cb, 32, MM_TAG_PGM, (void **)&pThis);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    pThis->u32Magic     = PGMRZDYNMAP_MAGIC;
+    pThis->paPages      = RT_ALIGN_PT(pThis + 1, 32, PPGMRZDYNMAPENTRY);
+    pThis->cPages       = cPages;
+    pThis->cLoad        = 0;
+    pThis->cMaxLoad     = 0;
+    pThis->cGuardPages  = 0;
+    pThis->cUsers       = 1;
+
+    for (size_t iPage = 0; iPage < cPages; iPage++)
+    {
+        pThis->paPages[iPage].HCPhys = NIL_RTHCPHYS;
+        pThis->paPages[iPage].pvPage = pVM->pgm.s.pbDynPageMapBaseGC + iPage * PAGE_SIZE;
+        pThis->paPages[iPage].cRefs  = 0;
+        pThis->paPages[iPage].uPte.pLegacy = &pVM->pgm.s.paDynPageMap32BitPTEsGC[iPage];
+        pThis->paPages[iPage].uPte.pPae    = (PX86PTEPAE)&pVM->pgm.s.paDynPageMapPaePTEsGC[iPage];
+    }
+
+    pVM->pgm.s.pRCDynMap = pThis;
+
+    /*
+     * Initialize the autosets the VM.
+     */
+    rc = pgmRZDynMapInitAutoSetsForVM(pVM);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    return VINF_SUCCESS;
+}
+
+#endif /* IN_RC */
+
+/**
+ * Release references to a page, caller owns the spin lock.
+ *
+ * @param   pThis       The dynamic mapping cache instance.
+ * @param   iPage       The page.
+ * @param   cRefs       The number of references to release.
+ */
+DECLINLINE(void) pgmRZDynMapReleasePageLocked(PPGMRZDYNMAP pThis, uint32_t iPage, int32_t cRefs)
+{
+    cRefs = ASMAtomicSubS32(&pThis->paPages[iPage].cRefs, cRefs) - cRefs;
+    AssertMsg(cRefs >= 0, ("%d\n", cRefs));
+    if (!cRefs)
+    {
+        pThis->cLoad--;
+#ifdef PGMRZDYNMAP_STRICT_RELEASE
+        pThis->paPages[iPage].HCPhys = NIL_RTHCPHYS;
+        ASMAtomicBitClear(pThis->paPages[iPage].uPte.pv, X86_PTE_BIT_P);
+        ASMInvalidatePage((uintptr_t)pThis->paPages[iPage].pvPage);
+#endif
+    }
+}
+
+
+/**
+ * Release references to a page, caller does not own the spin lock.
+ *
+ * @param   pThis       The dynamic mapping cache instance.
+ * @param   iPage       The page.
+ * @param   cRefs       The number of references to release.
+ */
+static void pgmRZDynMapReleasePage(PPGMRZDYNMAP pThis, uint32_t iPage, uint32_t cRefs)
+{
+    PGMRZDYNMAP_SPINLOCK_ACQUIRE(pThis);
+    pgmRZDynMapReleasePageLocked(pThis, iPage, cRefs);
+    PGMRZDYNMAP_SPINLOCK_RELEASE(pThis);
+}
+
+
+/**
+ * pgmR0DynMapPage worker that deals with the tedious bits.
+ *
+ * @returns The page index on success, UINT32_MAX on failure.
+ * @param   pThis   The dynamic mapping cache instance.
+ * @param   HCPhys  The address of the page to be mapped.
+ * @param   iPage   The page index pgmR0DynMapPage hashed HCPhys to.
+ * @param   pVCpu   The cross context virtual CPU structure of the calling EMT.
+ *                  For statistics.
+ * @param   pfNew   Set to @c true if a new entry was made and @c false if
+ *                  an old entry was found and reused.
+ */
+static uint32_t pgmR0DynMapPageSlow(PPGMRZDYNMAP pThis, RTHCPHYS HCPhys, uint32_t iPage, PVMCPU pVCpu, bool *pfNew)
+{
+    STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapPageSlow); RT_NOREF_PV(pVCpu);
+
+    /*
+     * Check if any of the first 3 pages are unreferenced since the caller
+     * already has made sure they aren't matching.
+     */
+#ifdef VBOX_WITH_STATISTICS
+    bool                fLooped = false;
+#endif
+    uint32_t const      cPages  = pThis->cPages;
+    PPGMRZDYNMAPENTRY   paPages = pThis->paPages;
+    uint32_t            iFreePage;
+    if (!paPages[iPage].cRefs)
+        iFreePage = iPage;
+    else if (!paPages[(iPage + 1) % cPages].cRefs)
+        iFreePage   = (iPage + 1) % cPages;
+    else if (!paPages[(iPage + 2) % cPages].cRefs)
+        iFreePage   = (iPage + 2) % cPages;
+    else
+    {
+        /*
+         * Search for an unused or matching entry.
+         */
+        iFreePage = (iPage + 3) % cPages;
+        for (;;)
+        {
+            if (paPages[iFreePage].HCPhys == HCPhys)
+            {
+                STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapPageSlowLoopHits);
+                *pfNew = false;
+                return iFreePage;
+            }
+            if (!paPages[iFreePage].cRefs)
+                break;
+
+            /* advance */
+            iFreePage = (iFreePage + 1) % cPages;
+            if (RT_UNLIKELY(iFreePage == iPage))
+                return UINT32_MAX;
+        }
+        STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapPageSlowLoopMisses);
+#ifdef VBOX_WITH_STATISTICS
+        fLooped = true;
+#endif
+    }
+    Assert(iFreePage < cPages);
+
+#if 0 //def VBOX_WITH_STATISTICS
+    /* Check for lost hits. */
+    if (!fLooped)
+        for (uint32_t iPage2 = (iPage + 3) % cPages; iPage2 != iPage; iPage2 = (iPage2 + 1) % cPages)
+            if (paPages[iPage2].HCPhys == HCPhys)
+                STAM_COUNTER_INC(&pVCpu->pgm.s.StatRZDynMapPageSlowLostHits);
+#endif
+
+    /*
+     * Setup the new entry.
+     */
+    *pfNew = true;
+    /*Log6(("pgmR0DynMapPageSlow: old - %RHp %#x %#llx\n", paPages[iFreePage].HCPhys, paPages[iFreePage].cRefs, paPages[iFreePage].uPte.pPae->u));*/
+    paPages[iFreePage].HCPhys = HCPhys;
+#ifndef IN_RC
+    RTCpuSetFill(&paPages[iFreePage].PendingSet);
+
+    if (pThis->fLegacyMode)
+#endif
+    {
+        X86PGUINT       uOld  = paPages[iFreePage].uPte.pLegacy->u;
+        X86PGUINT       uOld2 = uOld; NOREF(uOld2);
+        X86PGUINT       uNew  = (uOld & (X86_PTE_G | X86_PTE_PAT | X86_PTE_PCD | X86_PTE_PWT))
+                              | X86_PTE_P | X86_PTE_RW | X86_PTE_A | X86_PTE_D
+                              | (HCPhys & X86_PTE_PG_MASK);
+        while (!ASMAtomicCmpXchgExU32(&paPages[iFreePage].uPte.pLegacy->u, uNew, uOld, &uOld))
+            AssertMsgFailed(("uOld=%#x uOld2=%#x uNew=%#x\n", uOld, uOld2, uNew));
+        Assert(paPages[iFreePage].uPte.pLegacy->u == uNew);
+    }
+#ifndef IN_RC
+    else
+#endif
+    {
+        X86PGPAEUINT    uOld  = paPages[iFreePage].uPte.pPae->u;
+        X86PGPAEUINT    uOld2 = uOld; NOREF(uOld2);
+        X86PGPAEUINT    uNew  = (uOld & (X86_PTE_G | X86_PTE_PAT | X86_PTE_PCD | X86_PTE_PWT))
+                              | X86_PTE_P | X86_PTE_RW | X86_PTE_A | X86_PTE_D
+                              | (HCPhys & X86_PTE_PAE_PG_MASK);
+        while (!ASMAtomicCmpXchgExU64(&paPages[iFreePage].uPte.pPae->u, uNew, uOld, &uOld))
+            AssertMsgFailed(("uOld=%#llx uOld2=%#llx uNew=%#llx\n", uOld, uOld2, uNew));
+        Assert(paPages[iFreePage].uPte.pPae->u == uNew);
+        /*Log6(("pgmR0DynMapPageSlow: #%x - %RHp %p %#llx\n", iFreePage, HCPhys, paPages[iFreePage].pvPage, uNew));*/
+    }
+    return iFreePage;
+}
+
+
+/**
+ * Maps a page into the pool.
+ *
+ * @returns Page index on success, UINT32_MAX on failure.
+ * @param   pThis       The dynamic mapping cache instance.
+ * @param   HCPhys      The address of the page to be mapped.
+ * @param   iRealCpu    The real cpu set index. (optimization)
+ * @param   pVCpu       The cross context virtual CPU structure of the calling
+ *                      EMT.  For statistics.
+ * @param   ppvPage     Where to the page address.
+ */
+DECLINLINE(uint32_t) pgmR0DynMapPage(PPGMRZDYNMAP pThis, RTHCPHYS HCPhys, int32_t iRealCpu, PVMCPU pVCpu, void **ppvPage)
+{
+    PGMRZDYNMAP_SPINLOCK_ACQUIRE(pThis);
+    AssertMsg(!(HCPhys & PAGE_OFFSET_MASK), ("HCPhys=%RHp\n", HCPhys));
+    STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapPage);
+
+    /*
+     * Find an entry, if possible a matching one. The HCPhys address is hashed
+     * down to a page index, collisions are handled by linear searching.
+     * Optimized for a hit in the first 3 pages.
+     *
+     * Field easy hits here and defer the tedious searching and inserting
+     * to pgmR0DynMapPageSlow().
+     */
+    bool                fNew    = false;
+    uint32_t const      cPages  = pThis->cPages;
+    uint32_t            iPage   = (HCPhys >> PAGE_SHIFT) % cPages;
+    PPGMRZDYNMAPENTRY   paPages = pThis->paPages;
+    if (RT_LIKELY(paPages[iPage].HCPhys == HCPhys))
+        STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapPageHits0);
+    else
+    {
+        uint32_t        iPage2 = (iPage + 1) % cPages;
+        if (RT_LIKELY(paPages[iPage2].HCPhys == HCPhys))
+        {
+            iPage = iPage2;
+            STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapPageHits1);
+        }
+        else
+        {
+            iPage2 = (iPage + 2) % cPages;
+            if (paPages[iPage2].HCPhys == HCPhys)
+            {
+                iPage = iPage2;
+                STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapPageHits2);
+            }
+            else
+            {
+                iPage = pgmR0DynMapPageSlow(pThis, HCPhys, iPage, pVCpu, &fNew);
+                if (RT_UNLIKELY(iPage == UINT32_MAX))
+                {
+                    PGMRZDYNMAP_SPINLOCK_RELEASE(pThis);
+                    *ppvPage = NULL;
+                    return iPage;
+                }
+            }
+        }
+    }
+
+    /*
+     * Reference it, update statistics and get the return address.
+     */
+    int32_t cRefs = ASMAtomicIncS32(&paPages[iPage].cRefs);
+    if (cRefs == 1)
+    {
+        pThis->cLoad++;
+        if (pThis->cLoad > pThis->cMaxLoad)
+            pThis->cMaxLoad = pThis->cLoad;
+        AssertMsg(pThis->cLoad <= pThis->cPages - pThis->cGuardPages, ("%d/%d\n", pThis->cLoad, pThis->cPages - pThis->cGuardPages));
+    }
+    else if (RT_UNLIKELY(cRefs <= 0))
+    {
+        ASMAtomicDecS32(&paPages[iPage].cRefs);
+        PGMRZDYNMAP_SPINLOCK_RELEASE(pThis);
+        *ppvPage = NULL;
+        AssertLogRelMsgFailedReturn(("cRefs=%d iPage=%u HCPhys=%RHp\n", cRefs, iPage, HCPhys), UINT32_MAX);
+    }
+    void *pvPage = paPages[iPage].pvPage;
+
+#ifndef IN_RC
+    /*
+     * Invalidate the entry?
+     */
+    bool fInvalidateIt = RTCpuSetIsMemberByIndex(&paPages[iPage].PendingSet, iRealCpu);
+    if (RT_UNLIKELY(fInvalidateIt))
+        RTCpuSetDelByIndex(&paPages[iPage].PendingSet, iRealCpu);
+#else
+    NOREF(iRealCpu);
+#endif
+
+    PGMRZDYNMAP_SPINLOCK_RELEASE(pThis);
+
+    /*
+     * Do the actual invalidation outside the spinlock.
+     */
+#ifdef IN_RC
+    if (RT_UNLIKELY(fNew))
+#else
+    if (RT_UNLIKELY(fInvalidateIt))
+#endif
+    {
+        STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapPageInvlPg);
+        ASMInvalidatePage((uintptr_t)pvPage);
+    }
+
+    *ppvPage = pvPage;
+    return iPage;
+}
+
+
+/**
+ * Assert the integrity of the pool.
+ *
+ * @returns VBox status code.
+ */
+static int pgmRZDynMapAssertIntegrity(PPGMRZDYNMAP pThis)
+{
+    /*
+     * Basic pool stuff that doesn't require any lock, just assumes we're a user.
+     */
+    if (!pThis)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_POINTER);
+    AssertReturn(pThis->u32Magic == PGMRZDYNMAP_MAGIC, VERR_INVALID_MAGIC);
+    if (!pThis->cUsers)
+        return VERR_INVALID_PARAMETER;
+
+    PGMRZDYNMAP_SPINLOCK_ACQUIRE(pThis);
+
+#define CHECK_RET(expr, a) \
+    do { \
+        if (RT_UNLIKELY(!(expr))) \
+        { \
+            PGMRZDYNMAP_SPINLOCK_RELEASE(pThis); \
+            RTAssertMsg1Weak(#expr, __LINE__, __FILE__, __PRETTY_FUNCTION__); \
+            RTAssertMsg2Weak a; \
+            return VERR_PGM_DYNMAP_IPE; \
+        } \
+    } while (0)
+
+    /*
+     * Check that the PTEs are correct.
+     */
+    uint32_t            cGuard      = 0;
+    uint32_t            cLoad       = 0;
+    PPGMRZDYNMAPENTRY   paPages     = pThis->paPages;
+
+#ifndef IN_RC
+    if (pThis->fLegacyMode)
+#endif
+    {
+#ifdef IN_RING0
+        PCX86PGUINT     paSavedPTEs = (PCX86PGUINT)pThis->pvSavedPTEs; NOREF(paSavedPTEs);
+#endif
+        uint32_t        iPage       = pThis->cPages;
+        while (iPage-- > 0)
+        {
+            CHECK_RET(!((uintptr_t)paPages[iPage].pvPage & PAGE_OFFSET_MASK), ("#%u: %p\n", iPage, paPages[iPage].pvPage));
+            if (    paPages[iPage].cRefs  == PGMR0DYNMAP_GUARD_PAGE_REF_COUNT
+                &&  paPages[iPage].HCPhys == PGMR0DYNMAP_GUARD_PAGE_HCPHYS)
+            {
+#ifdef PGMR0DYNMAP_GUARD_NP
+                CHECK_RET(paPages[iPage].uPte.pLegacy->u == (paSavedPTEs[iPage] & ~(X86PGUINT)X86_PTE_P),
+                          ("#%u: %#x %#x", iPage, paPages[iPage].uPte.pLegacy->u, paSavedPTEs[iPage]));
+#else
+                CHECK_RET(paPages[iPage].uPte.pLegacy->u == PGMR0DYNMAP_GUARD_PAGE_LEGACY_PTE,
+                          ("#%u: %#x", iPage, paPages[iPage].uPte.pLegacy->u));
+#endif
+                cGuard++;
+            }
+            else if (paPages[iPage].HCPhys != NIL_RTHCPHYS)
+            {
+                CHECK_RET(!(paPages[iPage].HCPhys & PAGE_OFFSET_MASK), ("#%u: %RHp\n", iPage, paPages[iPage].HCPhys));
+                X86PGUINT uPte = X86_PTE_P | X86_PTE_RW | X86_PTE_A | X86_PTE_D
+#ifdef IN_RING0
+                               | (paSavedPTEs[iPage] & (X86_PTE_G | X86_PTE_PAT | X86_PTE_PCD | X86_PTE_PWT))
+#endif
+                               | (paPages[iPage].HCPhys & X86_PTE_PAE_PG_MASK);
+                CHECK_RET(paPages[iPage].uPte.pLegacy->u == uPte,
+                          ("#%u: %#x %#x", iPage, paPages[iPage].uPte.pLegacy->u, uPte));
+                if (paPages[iPage].cRefs)
+                    cLoad++;
+            }
+#if defined(IN_RING0) && !defined(PGMRZDYNMAP_STRICT_RELEASE)
+            else
+                CHECK_RET(paPages[iPage].uPte.pLegacy->u == paSavedPTEs[iPage],
+                          ("#%u: %#x %#x", iPage, paPages[iPage].uPte.pLegacy->u, paSavedPTEs[iPage]));
+#endif
+        }
+    }
+#ifndef IN_RC
+    else
+#endif
+    {
+#ifdef IN_RING0
+        PCX86PGPAEUINT  paSavedPTEs = (PCX86PGPAEUINT)pThis->pvSavedPTEs; NOREF(paSavedPTEs);
+#endif
+        uint32_t        iPage       = pThis->cPages;
+        while (iPage-- > 0)
+        {
+            CHECK_RET(!((uintptr_t)paPages[iPage].pvPage & PAGE_OFFSET_MASK), ("#%u: %p\n", iPage, paPages[iPage].pvPage));
+            if (    paPages[iPage].cRefs  == PGMR0DYNMAP_GUARD_PAGE_REF_COUNT
+                &&  paPages[iPage].HCPhys == PGMR0DYNMAP_GUARD_PAGE_HCPHYS)
+            {
+#ifdef PGMR0DYNMAP_GUARD_NP
+                CHECK_RET(paPages[iPage].uPte.pPae->u == (paSavedPTEs[iPage] & ~(X86PGPAEUINT)X86_PTE_P),
+                          ("#%u: %#llx %#llx", iPage, paPages[iPage].uPte.pPae->u, paSavedPTEs[iPage]));
+#else
+                CHECK_RET(paPages[iPage].uPte.pPae->u == PGMR0DYNMAP_GUARD_PAGE_PAE_PTE,
+                          ("#%u: %#llx", iPage, paPages[iPage].uPte.pPae->u));
+#endif
+                cGuard++;
+            }
+            else if (paPages[iPage].HCPhys != NIL_RTHCPHYS)
+            {
+                CHECK_RET(!(paPages[iPage].HCPhys & PAGE_OFFSET_MASK), ("#%u: %RHp\n", iPage, paPages[iPage].HCPhys));
+                X86PGPAEUINT uPte = X86_PTE_P | X86_PTE_RW | X86_PTE_A | X86_PTE_D
+#ifdef IN_RING0
+                                  | (paSavedPTEs[iPage] & (X86_PTE_G | X86_PTE_PAT | X86_PTE_PCD | X86_PTE_PWT))
+#endif
+                                  | (paPages[iPage].HCPhys & X86_PTE_PAE_PG_MASK);
+                CHECK_RET(paPages[iPage].uPte.pPae->u == uPte,
+                          ("#%u: %#llx %#llx", iPage, paPages[iPage].uPte.pLegacy->u, uPte));
+                if (paPages[iPage].cRefs)
+                    cLoad++;
+            }
+#ifdef IN_RING0
+            else
+                CHECK_RET(paPages[iPage].uPte.pPae->u == paSavedPTEs[iPage],
+                          ("#%u: %#llx %#llx", iPage, paPages[iPage].uPte.pPae->u, paSavedPTEs[iPage]));
+#endif
+        }
+    }
+
+    CHECK_RET(cLoad == pThis->cLoad, ("%u %u\n", cLoad, pThis->cLoad));
+    CHECK_RET(cGuard == pThis->cGuardPages, ("%u %u\n", cGuard, pThis->cGuardPages));
+
+#undef CHECK_RET
+    PGMRZDYNMAP_SPINLOCK_RELEASE(pThis);
+    return VINF_SUCCESS;
+}
+
+#ifdef IN_RING0
+/**
+ * Assert the integrity of the pool.
+ *
+ * @returns VBox status code.
+ */
+VMMR0DECL(int) PGMR0DynMapAssertIntegrity(void)
+{
+    return pgmRZDynMapAssertIntegrity(g_pPGMR0DynMap);
+}
+#endif /* IN_RING0 */
+
+#ifdef IN_RC
+/**
+ * Assert the integrity of the pool.
+ *
+ * @returns VBox status code.
+ */
+VMMRCDECL(int) PGMRCDynMapAssertIntegrity(PVM pVM)
+{
+    return pgmRZDynMapAssertIntegrity((PPGMRZDYNMAP)pVM->pgm.s.pRCDynMap);
+}
+#endif /* IN_RC */
+
+
+/**
+ * As a final resort for a (somewhat) full auto set or full cache, try merge
+ * duplicate entries and flush the ones we can.
+ *
+ * @param   pSet        The set.
+ */
+static void pgmDynMapOptimizeAutoSet(PPGMMAPSET pSet)
+{
+    LogFlow(("pgmDynMapOptimizeAutoSet\n"));
+
+    for (uint32_t i = 0 ; i < pSet->cEntries; i++)
+    {
+        /*
+         * Try merge entries.
+         */
+        uint16_t const  iPage = pSet->aEntries[i].iPage;
+        uint32_t        j     = i + 1;
+        while (   j < pSet->cEntries
+               && (   pSet->iSubset == UINT32_MAX
+                   || pSet->iSubset < pSet->cEntries) )
+        {
+            if (pSet->aEntries[j].iPage != iPage)
+                j++;
+            else
+            {
+                uint32_t const  cHardRefs    = (uint32_t)pSet->aEntries[i].cRefs
+                                             + (uint32_t)pSet->aEntries[j].cRefs;
+                uint32_t        cInlinedRefs = (uint32_t)pSet->aEntries[i].cInlinedRefs
+                                             + (uint32_t)pSet->aEntries[j].cInlinedRefs;
+                uint32_t        cUnrefs      = (uint32_t)pSet->aEntries[i].cUnrefs
+                                             + (uint32_t)pSet->aEntries[j].cUnrefs;
+                uint32_t        cSub         = RT_MIN(cUnrefs, cInlinedRefs);
+                cInlinedRefs -= cSub;
+                cUnrefs      -= cSub;
+
+                if (    cHardRefs    < UINT16_MAX
+                    &&  cInlinedRefs < UINT16_MAX
+                    &&  cUnrefs      < UINT16_MAX)
+                {
+                    /* merge j into i removing j. */
+                    Log2(("pgmDynMapOptimizeAutoSet: Merging #%u into #%u\n", j, i));
+                    pSet->aEntries[i].cRefs        = cHardRefs;
+                    pSet->aEntries[i].cInlinedRefs = cInlinedRefs;
+                    pSet->aEntries[i].cUnrefs      = cUnrefs;
+                    pSet->cEntries--;
+                    if (j < pSet->cEntries)
+                    {
+                        pSet->aEntries[j] = pSet->aEntries[pSet->cEntries];
+                        PGMRZDYNMAP_ZAP_ENTRY(&pSet->aEntries[pSet->cEntries]);
+                    }
+                    else
+                        PGMRZDYNMAP_ZAP_ENTRY(&pSet->aEntries[j]);
+                }
+#if 0 /* too complicated, skip it. */
+                else
+                {
+                    /* migrate the max number of refs from j into i and quit the inner loop. */
+                    uint32_t cMigrate = UINT16_MAX - 1 - pSet->aEntries[i].cRefs;
+                    Assert(pSet->aEntries[j].cRefs > cMigrate);
+                    pSet->aEntries[j].cRefs -= cMigrate;
+                    pSet->aEntries[i].cRefs = UINT16_MAX - 1;
+                    break;
+                }
+#endif
+            }
+        }
+
+        /*
+         * Try make use of the unused hinting (cUnrefs) to evict entries
+         * from both the set as well as the mapping cache.
+         */
+
+        uint32_t const cTotalRefs = (uint32_t)pSet->aEntries[i].cRefs + pSet->aEntries[i].cInlinedRefs;
+        Log2(("pgmDynMapOptimizeAutoSet: #%u/%u/%u pvPage=%p iPage=%u cRefs=%u cInlinedRefs=%u cUnrefs=%u cTotalRefs=%u\n",
+              i,
+              pSet->iSubset,
+              pSet->cEntries,
+              pSet->aEntries[i].pvPage,
+              pSet->aEntries[i].iPage,
+              pSet->aEntries[i].cRefs,
+              pSet->aEntries[i].cInlinedRefs,
+              pSet->aEntries[i].cUnrefs,
+              cTotalRefs));
+        Assert(cTotalRefs >= pSet->aEntries[i].cUnrefs);
+
+        if (    cTotalRefs == pSet->aEntries[i].cUnrefs
+            &&  (   pSet->iSubset == UINT32_MAX
+                 || pSet->iSubset < pSet->cEntries)
+           )
+        {
+            Log2(("pgmDynMapOptimizeAutoSet: Releasing iPage=%d/%p\n", pSet->aEntries[i].iPage, pSet->aEntries[i].pvPage));
+            //LogFlow(("pgmDynMapOptimizeAutoSet: Releasing iPage=%d/%p\n", pSet->aEntries[i].iPage, pSet->aEntries[i].pvPage));
+            pgmRZDynMapReleasePage(PGMRZDYNMAP_SET_2_DYNMAP(pSet),
+                                   pSet->aEntries[i].iPage,
+                                   pSet->aEntries[i].cRefs);
+            pSet->cEntries--;
+            if (i < pSet->cEntries)
+            {
+                pSet->aEntries[i] = pSet->aEntries[pSet->cEntries];
+                PGMRZDYNMAP_ZAP_ENTRY(&pSet->aEntries[pSet->cEntries]);
+            }
+
+            i--;
+        }
+    }
+}
+
+
+
+
+/**
+ * Signals the start of a new set of mappings.
+ *
+ * Mostly for strictness. PGMDynMapHCPage won't work unless this
+ * API is called.
+ *
+ * @param   pVCpu       The cross context virtual CPU structure of the calling EMT.
+ */
+VMMDECL(void) PGMRZDynMapStartAutoSet(PVMCPU pVCpu)
+{
+    LogFlow(("PGMRZDynMapStartAutoSet:\n"));
+    Assert(pVCpu->pgm.s.AutoSet.cEntries == PGMMAPSET_CLOSED);
+    Assert(pVCpu->pgm.s.AutoSet.iSubset == UINT32_MAX);
+    pVCpu->pgm.s.AutoSet.cEntries = 0;
+    pVCpu->pgm.s.AutoSet.iCpu = PGMRZDYNMAP_CUR_CPU();
+}
+
+
+#ifdef IN_RING0
+/**
+ * Starts or migrates the autoset of a virtual CPU.
+ *
+ * This is used by HMR0Enter.  When we've longjumped out of the HM
+ * execution loop with the set open, we'll migrate it when re-entering.  While
+ * under normal circumstances, we'll start it so VMXR0LoadGuestState can access
+ * guest memory.
+ *
+ * @returns @c true if started, @c false if migrated.
+ * @param   pVCpu       The cross context virtual CPU structure of the calling EMT.
+ * @thread  EMT
+ */
+VMMR0DECL(bool) PGMR0DynMapStartOrMigrateAutoSet(PVMCPU pVCpu)
+{
+    bool fStartIt = pVCpu->pgm.s.AutoSet.cEntries == PGMMAPSET_CLOSED;
+    if (fStartIt)
+        PGMRZDynMapStartAutoSet(pVCpu);
+    else
+        PGMR0DynMapMigrateAutoSet(pVCpu);
+    return fStartIt;
+}
+#endif /* IN_RING0 */
+
+
+/**
+ * Checks if the set has high load.
+ *
+ * @returns true on high load, otherwise false.
+ * @param   pSet            The set.
+ */
+DECLINLINE(bool) pgmRZDynMapHasHighLoad(PPGMMAPSET pSet)
+{
+#ifdef IN_RC
+    if (pSet->cEntries < MM_HYPER_DYNAMIC_SIZE / PAGE_SIZE / 2)
+        return false;
+#endif
+
+    PPGMRZDYNMAP pThis = PGMRZDYNMAP_SET_2_DYNMAP(pSet);
+    uint32_t cUnusedPages = pThis->cPages - pThis->cLoad;
+#ifdef IN_RC
+    return cUnusedPages <= MM_HYPER_DYNAMIC_SIZE / PAGE_SIZE * 36 / 100;
+#else
+    return cUnusedPages <= PGMR0DYNMAP_PAGES_PER_CPU_MIN;
+#endif
+}
+
+
+/**
+ * Worker that performs the actual flushing of the set.
+ *
+ * @param   pSet        The set to flush.
+ * @param   cEntries    The number of entries.
+ */
+DECLINLINE(void) pgmDynMapFlushAutoSetWorker(PPGMMAPSET pSet, uint32_t cEntries)
+{
+    /*
+     * Release any pages it's referencing.
+     */
+    if (    cEntries != 0
+        &&  RT_LIKELY(cEntries <= RT_ELEMENTS(pSet->aEntries)))
+    {
+        PPGMRZDYNMAP    pThis   = PGMRZDYNMAP_SET_2_DYNMAP(pSet);
+        PGMRZDYNMAP_SPINLOCK_ACQUIRE(pThis);
+
+        uint32_t i = cEntries;
+        while (i-- > 0)
+        {
+            uint32_t iPage = pSet->aEntries[i].iPage;
+            Assert(iPage < pThis->cPages);
+            int32_t  cRefs = pSet->aEntries[i].cRefs;
+            Assert(cRefs > 0);
+            pgmRZDynMapReleasePageLocked(pThis, iPage, cRefs);
+
+            PGMRZDYNMAP_ZAP_ENTRY(&pSet->aEntries[i]);
+        }
+
+        Assert(pThis->cLoad <= pThis->cPages - pThis->cGuardPages);
+        PGMRZDYNMAP_SPINLOCK_RELEASE(pThis);
+    }
+}
+
+
+/**
+ * Releases the dynamic memory mappings made by PGMDynMapHCPage and associates
+ * since the PGMDynMapStartAutoSet call.
+ *
+ * @param   pVCpu       The cross context virtual CPU structure of the calling EMT.
+ */
+VMMDECL(void) PGMRZDynMapReleaseAutoSet(PVMCPU pVCpu)
+{
+    PPGMMAPSET  pSet = &pVCpu->pgm.s.AutoSet;
+
+    /*
+     * Close and flush the set.
+     */
+    uint32_t    cEntries = pSet->cEntries;
+    AssertReturnVoid(cEntries != PGMMAPSET_CLOSED);
+    pSet->cEntries = PGMMAPSET_CLOSED;
+    pSet->iSubset = UINT32_MAX;
+    pSet->iCpu = -1;
+
+#ifdef IN_RC
+    if (RT_ELEMENTS(pSet->aEntries) > MM_HYPER_DYNAMIC_SIZE / PAGE_SIZE)
+        STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->aStatRZDynMapSetFilledPct[(cEntries * 10 / (MM_HYPER_DYNAMIC_SIZE / PAGE_SIZE)) % 11]);
+    else
+#endif
+        STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->aStatRZDynMapSetFilledPct[(cEntries * 10 / RT_ELEMENTS(pSet->aEntries)) % 11]);
+    if (cEntries > RT_ELEMENTS(pSet->aEntries) * 50 / 100)
+        Log(("PGMRZDynMapReleaseAutoSet: cEntries=%d\n", cEntries));
+    else
+        LogFlow(("PGMRZDynMapReleaseAutoSet: cEntries=%d\n", cEntries));
+
+    pgmDynMapFlushAutoSetWorker(pSet, cEntries);
+}
+
+
+/**
+ * Flushes the set if it's above a certain threshold.
+ *
+ * @param   pVCpu       The cross context virtual CPU structure of the calling EMT.
+ */
+VMMDECL(void) PGMRZDynMapFlushAutoSet(PVMCPU pVCpu)
+{
+    PPGMMAPSET  pSet = &pVCpu->pgm.s.AutoSet;
+    AssertMsg(pSet->iCpu == PGMRZDYNMAP_CUR_CPU(), ("%d %d efl=%#x\n", pSet->iCpu, PGMRZDYNMAP_CUR_CPU(), ASMGetFlags()));
+
+    /*
+     * Only flush it if it's 45% full.
+     */
+    uint32_t cEntries = pSet->cEntries;
+    AssertReturnVoid(cEntries != PGMMAPSET_CLOSED);
+    Assert(pSet->iSubset == UINT32_MAX);
+#ifdef IN_RC
+    if (RT_ELEMENTS(pSet->aEntries) > MM_HYPER_DYNAMIC_SIZE / PAGE_SIZE)
+        STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->aStatRZDynMapSetFilledPct[(cEntries * 10 / (MM_HYPER_DYNAMIC_SIZE / PAGE_SIZE)) % 11]);
+    else
+#endif
+        STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->aStatRZDynMapSetFilledPct[(cEntries * 10 / RT_ELEMENTS(pSet->aEntries)) % 11]);
+    if (   cEntries >= RT_ELEMENTS(pSet->aEntries) * 45 / 100
+        || pgmRZDynMapHasHighLoad(pSet))
+    {
+        pSet->cEntries = 0;
+        Log(("PGMDynMapFlushAutoSet: cEntries=%d\n", pSet->cEntries));
+
+        pgmDynMapFlushAutoSetWorker(pSet, cEntries);
+        AssertMsg(pSet->iCpu == PGMRZDYNMAP_CUR_CPU(), ("%d %d efl=%#x\n", pSet->iCpu, PGMRZDYNMAP_CUR_CPU(), ASMGetFlags()));
+    }
+}
+
+
+#ifndef IN_RC
+/**
+ * Migrates the automatic mapping set of the current vCPU if it's active and
+ * necessary.
+ *
+ * This is called when re-entering the hardware assisted execution mode after a
+ * nip down to ring-3.  We run the risk that the CPU might have change and we
+ * will therefore make sure all the cache entries currently in the auto set will
+ * be valid on the new CPU.  If the cpu didn't change nothing will happen as all
+ * the entries will have been flagged as invalidated.
+ *
+ * @param   pVCpu       The cross context virtual CPU structure of the calling EMT.
+ * @thread  EMT
+ */
+VMMR0DECL(void) PGMR0DynMapMigrateAutoSet(PVMCPU pVCpu)
+{
+    LogFlow(("PGMR0DynMapMigrateAutoSet\n"));
+    PPGMMAPSET      pSet     = &pVCpu->pgm.s.AutoSet;
+    int32_t         iRealCpu = PGMRZDYNMAP_CUR_CPU();
+    if (pSet->iCpu != iRealCpu)
+    {
+        uint32_t    i        = pSet->cEntries;
+        if (i != PGMMAPSET_CLOSED)
+        {
+            AssertMsg(i <= RT_ELEMENTS(pSet->aEntries), ("%#x (%u)\n", i, i));
+            if (i != 0 && RT_LIKELY(i <= RT_ELEMENTS(pSet->aEntries)))
+            {
+                PPGMRZDYNMAP    pThis  = PGMRZDYNMAP_SET_2_DYNMAP(pSet);
+                PGMRZDYNMAP_SPINLOCK_ACQUIRE(pThis);
+
+                while (i-- > 0)
+                {
+                    Assert(pSet->aEntries[i].cRefs > 0);
+                    uint32_t iPage = pSet->aEntries[i].iPage;
+                    Assert(iPage < pThis->cPages);
+                    if (RTCpuSetIsMemberByIndex(&pThis->paPages[iPage].PendingSet, iRealCpu))
+                    {
+                        RTCpuSetDelByIndex(&pThis->paPages[iPage].PendingSet, iRealCpu);
+                        PGMRZDYNMAP_SPINLOCK_RELEASE(pThis);
+
+                        ASMInvalidatePage((uintptr_t)pThis->paPages[iPage].pvPage);
+                        STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapMigrateInvlPg);
+
+                        PGMRZDYNMAP_SPINLOCK_REACQUIRE(pThis);
+                    }
+                }
+
+                PGMRZDYNMAP_SPINLOCK_RELEASE(pThis);
+            }
+        }
+        pSet->iCpu = iRealCpu;
+    }
+}
+#endif /* !IN_RC */
+
+
+/**
+ * Worker function that flushes the current subset.
+ *
+ * This is called when the set is popped or when the set
+ * hash a too high load. As also pointed out elsewhere, the
+ * whole subset thing is a hack for working around code that
+ * accesses too many pages. Like PGMPool.
+ *
+ * @param   pSet        The set which subset to flush.
+ */
+static void pgmDynMapFlushSubset(PPGMMAPSET pSet)
+{
+    uint32_t iSubset = pSet->iSubset;
+    uint32_t i       = pSet->cEntries;
+    Assert(i <= RT_ELEMENTS(pSet->aEntries));
+    if (    i > iSubset
+        &&  i <= RT_ELEMENTS(pSet->aEntries))
+    {
+        Log(("pgmDynMapFlushSubset: cEntries=%d iSubset=%d\n", pSet->cEntries, iSubset));
+        pSet->cEntries = iSubset;
+
+        PPGMRZDYNMAP    pThis = PGMRZDYNMAP_SET_2_DYNMAP(pSet);
+        PGMRZDYNMAP_SPINLOCK_ACQUIRE(pThis);
+
+        while (i-- > iSubset)
+        {
+            uint32_t iPage = pSet->aEntries[i].iPage;
+            Assert(iPage < pThis->cPages);
+            int32_t  cRefs = pSet->aEntries[i].cRefs;
+            Assert(cRefs > 0);
+            pgmRZDynMapReleasePageLocked(pThis, iPage, cRefs);
+
+            PGMRZDYNMAP_ZAP_ENTRY(&pSet->aEntries[i]);
+        }
+
+        PGMRZDYNMAP_SPINLOCK_RELEASE(pThis);
+    }
+}
+
+
+/**
+ * Creates a subset.
+ *
+ * A subset is a hack to avoid having to rewrite code that touches a lot of
+ * pages. It prevents the mapping set from being overflowed by automatically
+ * flushing previous mappings when a certain threshold is reached.
+ *
+ * Pages mapped after calling this function are only valid until the next page
+ * is mapped.
+ *
+ * @returns The index of the previous subset. Pass this to
+ *          PGMDynMapPopAutoSubset when popping it.
+ * @param   pVCpu           The cross context virtual CPU structure of the calling EMT.
+ */
+VMMDECL(uint32_t) PGMRZDynMapPushAutoSubset(PVMCPU pVCpu)
+{
+    PPGMMAPSET      pSet = &pVCpu->pgm.s.AutoSet;
+    AssertReturn(pSet->cEntries != PGMMAPSET_CLOSED, UINT32_MAX);
+    uint32_t        iPrevSubset = pSet->iSubset;
+    LogFlow(("PGMRZDynMapPushAutoSubset: pVCpu=%p iPrevSubset=%u\n", pVCpu, iPrevSubset));
+
+    /*
+     * If it looks like we're approaching the max set size or mapping space
+     * optimize the set to drop off unused pages.
+     */
+    if (   pSet->cEntries > RT_ELEMENTS(pSet->aEntries) * 60 / 100
+        || pgmRZDynMapHasHighLoad(pSet))
+    {
+        STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapSetOptimize);
+        pgmDynMapOptimizeAutoSet(pSet);
+    }
+
+    pSet->iSubset = pSet->cEntries;
+    STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapSubsets);
+
+    AssertMsg(iPrevSubset <= pSet->iSubset || iPrevSubset == UINT32_MAX, ("iPrevSubset=%#x iSubset=%#x\n", iPrevSubset, pSet->iSubset));
+    return iPrevSubset;
+}
+
+
+/**
+ * Pops a subset created by a previous call to PGMDynMapPushAutoSubset.
+ *
+ * @param   pVCpu           The cross context virtual CPU structure of the calling EMT.
+ * @param   iPrevSubset     What PGMDynMapPushAutoSubset returned.
+ */
+VMMDECL(void) PGMRZDynMapPopAutoSubset(PVMCPU pVCpu, uint32_t iPrevSubset)
+{
+    PPGMMAPSET      pSet = &pVCpu->pgm.s.AutoSet;
+    uint32_t        cEntries = pSet->cEntries;
+    LogFlow(("PGMRZDynMapPopAutoSubset: pVCpu=%p iPrevSubset=%u iSubset=%u cEntries=%u\n", pVCpu, iPrevSubset, pSet->iSubset, cEntries));
+    AssertReturnVoid(cEntries != PGMMAPSET_CLOSED);
+    AssertMsgReturnVoid(pSet->iSubset >= iPrevSubset || iPrevSubset == UINT32_MAX, ("iPrevSubset=%u iSubset=%u cEntries=%u\n", iPrevSubset, pSet->iSubset, cEntries));
+#ifdef IN_RC
+    if (RT_ELEMENTS(pSet->aEntries) > MM_HYPER_DYNAMIC_SIZE / PAGE_SIZE)
+        STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->aStatRZDynMapSetFilledPct[(cEntries * 10 / (MM_HYPER_DYNAMIC_SIZE / PAGE_SIZE)) % 11]);
+    else
+#endif
+        STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->aStatRZDynMapSetFilledPct[(cEntries * 10 / RT_ELEMENTS(pSet->aEntries)) % 11]);
+    if (    cEntries >= RT_ELEMENTS(pSet->aEntries) * 40 / 100
+        &&  cEntries != pSet->iSubset)
+    {
+        pgmDynMapFlushSubset(pSet);
+        Assert(pSet->cEntries >= iPrevSubset || iPrevSubset == UINT32_MAX);
+    }
+    pSet->iSubset = iPrevSubset;
+}
+
+
+/**
+ * Indicates that the given page is unused and its mapping can be re-used.
+ *
+ * @param   pVCpu           The cross context virtual CPU structure of the calling EMT.
+ * @param   pvHint          The page that is now unused.  This does not have to
+ *                          point at the start of the page.  NULL is ignored.
+ */
+#ifdef LOG_ENABLED
+void pgmRZDynMapUnusedHint(PVMCPU pVCpu, void *pvHint, RT_SRC_POS_DECL)
+#else
+void pgmRZDynMapUnusedHint(PVMCPU pVCpu, void *pvHint)
+#endif
+{
+    /*
+     * Ignore NULL pointers and mask off the page offset bits.
+     */
+    if (pvHint == NULL)
+        return;
+    pvHint = (void *)((uintptr_t)pvHint & ~(uintptr_t)PAGE_OFFSET_MASK);
+
+    PPGMMAPSET  pSet    = &pVCpu->pgm.s.AutoSet;
+    uint32_t    iEntry  = pSet->cEntries;
+    AssertReturnVoid(iEntry > 0);
+
+    /*
+     * Find the entry in the usual unrolled fashion.
+     */
+    /** @todo add a hint to the set which entry was used last since it's not
+     *        always the last entry? */
+#define IS_MATCHING_ENTRY(pSet, iEntry, pvHint) \
+        (   (pSet)->aEntries[(iEntry)].pvPage == (pvHint) \
+         &&   (uint32_t)(pSet)->aEntries[(iEntry)].cRefs + (pSet)->aEntries[(iEntry)].cInlinedRefs \
+            > (pSet)->aEntries[(iEntry)].cUnrefs )
+    if (     iEntry >= 1 && IS_MATCHING_ENTRY(pSet, iEntry - 1, pvHint))
+        iEntry = iEntry - 1;
+    else if (iEntry >= 2 && IS_MATCHING_ENTRY(pSet, iEntry - 2, pvHint))
+        iEntry = iEntry - 2;
+    else if (iEntry >= 3 && IS_MATCHING_ENTRY(pSet, iEntry - 3, pvHint))
+        iEntry = iEntry - 3;
+    else if (iEntry >= 4 && IS_MATCHING_ENTRY(pSet, iEntry - 4, pvHint))
+        iEntry = iEntry - 4;
+    else if (iEntry >= 5 && IS_MATCHING_ENTRY(pSet, iEntry - 5, pvHint))
+        iEntry = iEntry - 5;
+    else if (iEntry >= 6 && IS_MATCHING_ENTRY(pSet, iEntry - 6, pvHint))
+        iEntry = iEntry - 6;
+    else if (iEntry >= 7 && IS_MATCHING_ENTRY(pSet, iEntry - 7, pvHint))
+        iEntry = iEntry - 7;
+    else
+    {
+        /*
+         * Loop till we find it.
+         */
+        bool fFound = false;
+        if (iEntry > 7)
+        {
+            iEntry -= 7;
+            while (iEntry-- > 0)
+                if (IS_MATCHING_ENTRY(pSet, iEntry, pvHint))
+                {
+                    fFound = true;
+                    break;
+                }
+        }
+        AssertMsgReturnVoid(fFound,
+                            ("pvHint=%p cEntries=%#x iSubset=%#x\n"
+                             "aEntries[0] = {%#x, %#x, %#x, %#x, %p}\n"
+                             "aEntries[1] = {%#x, %#x, %#x, %#x, %p}\n"
+                             "aEntries[2] = {%#x, %#x, %#x, %#x, %p}\n"
+                             "aEntries[3] = {%#x, %#x, %#x, %#x, %p}\n"
+                             "aEntries[4] = {%#x, %#x, %#x, %#x, %p}\n"
+                             "aEntries[5] = {%#x, %#x, %#x, %#x, %p}\n"
+                             ,
+                             pvHint, pSet->cEntries, pSet->iSubset,
+                             pSet->aEntries[0].iPage, pSet->aEntries[0].cRefs, pSet->aEntries[0].cInlinedRefs, pSet->aEntries[0].cUnrefs, pSet->aEntries[0].pvPage,
+                             pSet->aEntries[1].iPage, pSet->aEntries[1].cRefs, pSet->aEntries[1].cInlinedRefs, pSet->aEntries[1].cUnrefs, pSet->aEntries[1].pvPage,
+                             pSet->aEntries[2].iPage, pSet->aEntries[2].cRefs, pSet->aEntries[2].cInlinedRefs, pSet->aEntries[2].cUnrefs, pSet->aEntries[2].pvPage,
+                             pSet->aEntries[3].iPage, pSet->aEntries[3].cRefs, pSet->aEntries[3].cInlinedRefs, pSet->aEntries[3].cUnrefs, pSet->aEntries[3].pvPage,
+                             pSet->aEntries[4].iPage, pSet->aEntries[4].cRefs, pSet->aEntries[4].cInlinedRefs, pSet->aEntries[4].cUnrefs, pSet->aEntries[4].pvPage,
+                             pSet->aEntries[5].iPage, pSet->aEntries[5].cRefs, pSet->aEntries[5].cInlinedRefs, pSet->aEntries[5].cUnrefs, pSet->aEntries[5].pvPage));
+    }
+#undef IS_MATCHING_ENTRY
+
+    /*
+     * Update it.
+     */
+    uint32_t const  cTotalRefs = (uint32_t)pSet->aEntries[iEntry].cRefs + pSet->aEntries[iEntry].cInlinedRefs;
+    uint32_t const  cUnrefs    = pSet->aEntries[iEntry].cUnrefs;
+    LogFlow(("pgmRZDynMapUnusedHint: pvHint=%p #%u cRefs=%d cInlinedRefs=%d cUnrefs=%d (+1) cTotalRefs=%d %s(%d) %s\n",
+             pvHint, iEntry, pSet->aEntries[iEntry].cRefs, pSet->aEntries[iEntry].cInlinedRefs, cUnrefs, cTotalRefs, pszFile, iLine, pszFunction));
+    AssertReturnVoid(cTotalRefs > cUnrefs);
+
+    if (RT_LIKELY(cUnrefs < UINT16_MAX - 1))
+        pSet->aEntries[iEntry].cUnrefs++;
+    else if (pSet->aEntries[iEntry].cInlinedRefs)
+    {
+        uint32_t cSub = RT_MIN(pSet->aEntries[iEntry].cInlinedRefs, pSet->aEntries[iEntry].cUnrefs);
+        pSet->aEntries[iEntry].cInlinedRefs -= cSub;
+        pSet->aEntries[iEntry].cUnrefs      -= cSub;
+        pSet->aEntries[iEntry].cUnrefs++;
+    }
+    else
+        Log(("pgmRZDynMapUnusedHint: pvHint=%p ignored because of overflow! %s(%d) %s\n", pvHint, pszFile, iLine, pszFunction));
+
+#ifdef PGMRZDYNMAP_STRICT_RELEASE
+    /*
+     * Optimize the set to trigger the unmapping and invalidation of the page.
+     */
+    if (cUnrefs + 1 == cTotalRefs)
+        pgmDynMapOptimizeAutoSet(pSet);
+#endif
+}
+
+
+/**
+ * Common worker code for pgmRZDynMapHCPageInlined, pgmRZDynMapHCPageV2Inlined
+ * and pgmR0DynMapGCPageOffInlined.
+ *
+ * @returns VINF_SUCCESS, bails out to ring-3 on failure.
+ * @param   pSet        The set.
+ * @param   HCPhys      The physical address of the page.
+ * @param   ppv         Where to store the address of the mapping on success.
+ *
+ * @remarks This is a very hot path.
+ */
+int pgmRZDynMapHCPageCommon(PPGMMAPSET pSet, RTHCPHYS HCPhys, void **ppv RTLOG_COMMA_SRC_POS_DECL)
+{
+    AssertMsg(pSet->iCpu == PGMRZDYNMAP_CUR_CPU(), ("%d %d efl=%#x\n", pSet->iCpu, PGMRZDYNMAP_CUR_CPU(), ASMGetFlags()));
+    PVMCPU pVCpu = PGMRZDYNMAP_SET_2_VMCPU(pSet);
+    STAM_PROFILE_START(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapHCPage, a);
+
+    /*
+     * Map it.
+     */
+    void           *pvPage;
+    PPGMRZDYNMAP    pThis = PGMRZDYNMAP_SET_2_DYNMAP(pSet);
+    uint32_t        iPage = pgmR0DynMapPage(pThis, HCPhys, pSet->iCpu, pVCpu, &pvPage);
+    if (RT_UNLIKELY(iPage == UINT32_MAX))
+    {
+        /*
+         * We're out of mapping space, optimize our set to try remedy the
+         * situation.  (Only works if there are unreference hints.)
+         */
+        STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapSetOptimize);
+        pgmDynMapOptimizeAutoSet(pSet);
+
+        iPage = pgmR0DynMapPage(pThis, HCPhys, pSet->iCpu, pVCpu, &pvPage);
+        if (RT_UNLIKELY(iPage == UINT32_MAX))
+        {
+            RTAssertMsg2Weak("pgmRZDynMapHCPageCommon: cLoad=%u/%u cPages=%u cGuardPages=%u\n",
+                             pThis->cLoad, pThis->cMaxLoad, pThis->cPages, pThis->cGuardPages);
+            if (!g_fPGMR0DynMapTestRunning)
+                VMMRZCallRing3NoCpu(PGMRZDYNMAP_SET_2_VM(pSet), VMMCALLRING3_VM_R0_ASSERTION, 0);
+            *ppv = NULL;
+            STAM_PROFILE_STOP(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapHCPage, a);
+            return VERR_PGM_DYNMAP_FAILED;
+        }
+    }
+
+    /*
+     * Add the page to the auto reference set.
+     *
+     * The typical usage pattern means that the same pages will be mapped
+     * several times in the same set. We can catch most of these
+     * remappings by looking a few pages back into the set. (The searching
+     * and set optimizing path will hardly ever be used when doing this.)
+     */
+    AssertCompile(RT_ELEMENTS(pSet->aEntries) >= 8);
+    int32_t i = pSet->cEntries;
+    if (i-- < 5)
+    {
+        unsigned iEntry = pSet->cEntries++;
+        pSet->aEntries[iEntry].cRefs        = 1;
+        pSet->aEntries[iEntry].cUnrefs      = 0;
+        pSet->aEntries[iEntry].cInlinedRefs = 0;
+        pSet->aEntries[iEntry].iPage        = iPage;
+        pSet->aEntries[iEntry].pvPage       = pvPage;
+        pSet->aEntries[iEntry].HCPhys       = HCPhys;
+        pSet->aiHashTable[PGMMAPSET_HASH(HCPhys)] = iEntry;
+        LogFlow(("pgmRZDynMapHCPageCommon: pSet=%p HCPhys=%RHp #%u/%u/%p cRefs=%u/0/0 iPage=%#x  [a] %s(%d) %s\n",
+                 pSet, HCPhys, iEntry, iEntry + 1, pvPage, 1, iPage, pszFile, iLine, pszFunction));
+    }
+    /* Any of the last 5 pages? */
+    else if (   pSet->aEntries[i - 0].iPage == iPage
+             && pSet->aEntries[i - 0].cRefs < UINT16_MAX - 1)
+    {
+        pSet->aEntries[i - 0].cRefs++;
+        LogFlow(("pgmRZDynMapHCPageCommon: pSet=%p HCPhys=%RHp #%u/%u/%p cRefs=%u/%u/%u iPage=%#x [0] %s(%d) %s\n", pSet, HCPhys, i - 0, pSet->cEntries, pvPage, pSet->aEntries[i - 0].cRefs, pSet->aEntries[i - 0].cInlinedRefs, pSet->aEntries[i - 0].cUnrefs, iPage, pszFile, iLine, pszFunction));
+    }
+    else if (   pSet->aEntries[i - 1].iPage == iPage
+             && pSet->aEntries[i - 1].cRefs < UINT16_MAX - 1)
+    {
+        pSet->aEntries[i - 1].cRefs++;
+        LogFlow(("pgmRZDynMapHCPageCommon: pSet=%p HCPhys=%RHp #%u/%u/%p cRefs=%u/%u/%u iPage=%#x [1] %s(%d) %s\n", pSet, HCPhys, i - 1, pSet->cEntries, pvPage, pSet->aEntries[i - 1].cRefs, pSet->aEntries[i - 1].cInlinedRefs, pSet->aEntries[i - 1].cUnrefs, iPage, pszFile, iLine, pszFunction));
+    }
+    else if (   pSet->aEntries[i - 2].iPage == iPage
+             && pSet->aEntries[i - 2].cRefs < UINT16_MAX - 1)
+    {
+        pSet->aEntries[i - 2].cRefs++;
+        LogFlow(("pgmRZDynMapHCPageCommon: pSet=%p HCPhys=%RHp #%u/%u/%p cRefs=%u/%u/%u iPage=%#x [2] %s(%d) %s\n", pSet, HCPhys, i - 2, pSet->cEntries, pvPage, pSet->aEntries[i - 2].cRefs, pSet->aEntries[i - 2].cInlinedRefs, pSet->aEntries[i - 2].cUnrefs, iPage, pszFile, iLine, pszFunction));
+    }
+    else if (   pSet->aEntries[i - 3].iPage == iPage
+             && pSet->aEntries[i - 3].cRefs < UINT16_MAX - 1)
+    {
+        pSet->aEntries[i - 3].cRefs++;
+        LogFlow(("pgmRZDynMapHCPageCommon: pSet=%p HCPhys=%RHp #%u/%u/%p cRefs=%u/%u/%u iPage=%#x [4] %s(%d) %s\n", pSet, HCPhys, i - 3, pSet->cEntries, pvPage, pSet->aEntries[i - 3].cRefs, pSet->aEntries[i - 3].cInlinedRefs, pSet->aEntries[i - 3].cUnrefs, iPage, pszFile, iLine, pszFunction));
+    }
+    else if (   pSet->aEntries[i - 4].iPage == iPage
+             && pSet->aEntries[i - 4].cRefs < UINT16_MAX - 1)
+    {
+        pSet->aEntries[i - 4].cRefs++;
+        LogFlow(("pgmRZDynMapHCPageCommon: pSet=%p HCPhys=%RHp #%u/%u/%p cRefs=%u/%u/%u iPage=%#x [4] %s(%d) %s\n", pSet, HCPhys, i - 4, pSet->cEntries, pvPage, pSet->aEntries[i - 4].cRefs, pSet->aEntries[i - 4].cInlinedRefs, pSet->aEntries[i - 4].cUnrefs, iPage, pszFile, iLine, pszFunction));
+    }
+    /* Don't bother searching unless we're above a 60% load. */
+    else if (RT_LIKELY(i <= (int32_t)RT_ELEMENTS(pSet->aEntries) * 60 / 100))
+    {
+        unsigned iEntry = pSet->cEntries++;
+        pSet->aEntries[iEntry].cRefs        = 1;
+        pSet->aEntries[iEntry].cUnrefs      = 0;
+        pSet->aEntries[iEntry].cInlinedRefs = 0;
+        pSet->aEntries[iEntry].iPage        = iPage;
+        pSet->aEntries[iEntry].pvPage       = pvPage;
+        pSet->aEntries[iEntry].HCPhys       = HCPhys;
+        pSet->aiHashTable[PGMMAPSET_HASH(HCPhys)] = iEntry;
+        LogFlow(("pgmRZDynMapHCPageCommon: pSet=%p HCPhys=%RHp #%u/%u/%p cRefs=1/0/0 iPage=%#x [b] %s(%d) %s\n", pSet, HCPhys, iEntry, pSet->cEntries, pvPage, iPage, pszFile, iLine, pszFunction));
+    }
+    else
+    {
+        /* Search the rest of the set. */
+        Assert(pSet->cEntries <= RT_ELEMENTS(pSet->aEntries));
+        i -= 4;
+        while (i-- > 0)
+            if (    pSet->aEntries[i].iPage == iPage
+                &&  pSet->aEntries[i].cRefs < UINT16_MAX - 1)
+            {
+                pSet->aEntries[i].cRefs++;
+                STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapSetSearchHits);
+                LogFlow(("pgmRZDynMapHCPageCommon: pSet=%p HCPhys=%RHp #%u/%u/%p cRefs=%u/%u/%u iPage=%#x [c] %s(%d) %s\n", pSet, HCPhys, i, pSet->cEntries, pvPage, pSet->aEntries[i].cRefs, pSet->aEntries[i].cInlinedRefs, pSet->aEntries[i].cUnrefs, iPage, pszFile, iLine, pszFunction));
+                break;
+            }
+        if (i < 0)
+        {
+            STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapSetSearchMisses);
+#if 0 /* this is very bogus */
+            if (pSet->iSubset < pSet->cEntries)
+            {
+                STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapSetSearchFlushes);
+                STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->aStatRZDynMapSetFilledPct[(pSet->cEntries * 10 / RT_ELEMENTS(pSet->aEntries)) % 11]);
+                pgmDynMapFlushSubset(pSet);
+            }
+#endif
+
+            if (RT_UNLIKELY(pSet->cEntries >= RT_ELEMENTS(pSet->aEntries)))
+            {
+                STAM_COUNTER_INC(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapSetOptimize);
+                pgmDynMapOptimizeAutoSet(pSet);
+            }
+
+            if (RT_LIKELY(pSet->cEntries < RT_ELEMENTS(pSet->aEntries)))
+            {
+                unsigned iEntry = pSet->cEntries++;
+                pSet->aEntries[iEntry].cRefs        = 1;
+                pSet->aEntries[iEntry].cUnrefs      = 0;
+                pSet->aEntries[iEntry].cInlinedRefs = 0;
+                pSet->aEntries[iEntry].iPage        = iPage;
+                pSet->aEntries[iEntry].pvPage       = pvPage;
+                pSet->aEntries[iEntry].HCPhys       = HCPhys;
+                pSet->aiHashTable[PGMMAPSET_HASH(HCPhys)] = iEntry;
+                LogFlow(("pgmRZDynMapHCPageCommon: pSet=%p HCPhys=%RHp #%u/%u/%p cRefs=1/0/0 iPage=%#x [d] %s(%d) %s\n", pSet, HCPhys, iEntry, pSet->cEntries, pvPage, iPage, pszFile, iLine, pszFunction));
+            }
+            else
+            {
+                /* We're screwed. */
+                pgmRZDynMapReleasePage(pThis, iPage, 1);
+
+                RTAssertMsg2Weak("pgmRZDynMapHCPageCommon: set is full!\n");
+                if (!g_fPGMR0DynMapTestRunning)
+                    VMMRZCallRing3NoCpu(PGMRZDYNMAP_SET_2_VM(pSet), VMMCALLRING3_VM_R0_ASSERTION, 0);
+                *ppv = NULL;
+                STAM_PROFILE_STOP(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapHCPage, a);
+                return VERR_PGM_DYNMAP_FULL_SET;
+            }
+        }
+    }
+
+    *ppv = pvPage;
+    STAM_PROFILE_STOP(&pVCpu->pgm.s.CTX_SUFF(pStats)->StatRZDynMapHCPage, a);
+    return VINF_SUCCESS;
+}
+
+
+#if 0 /*def DEBUG*/
+/** For pgmR0DynMapTest3PerCpu. */
+typedef struct PGMR0DYNMAPTEST
+{
+    uint32_t            u32Expect;
+    uint32_t           *pu32;
+    uint32_t volatile   cFailures;
+} PGMR0DYNMAPTEST;
+typedef PGMR0DYNMAPTEST *PPGMR0DYNMAPTEST;
+
+/**
+ * Checks that the content of the page is the same on all CPUs, i.e. that there
+ * are no CPU specific PTs or similar nasty stuff involved.
+ *
+ * @param   idCpu           The current CPU.
+ * @param   pvUser1         Pointer a PGMR0DYNMAPTEST structure.
+ * @param   pvUser2         Unused, ignored.
+ */
+static DECLCALLBACK(void) pgmR0DynMapTest3PerCpu(RTCPUID idCpu, void *pvUser1, void *pvUser2)
+{
+    PPGMR0DYNMAPTEST    pTest = (PPGMR0DYNMAPTEST)pvUser1;
+    ASMInvalidatePage(pTest->pu32);
+    if (*pTest->pu32 != pTest->u32Expect)
+        ASMAtomicIncU32(&pTest->cFailures);
+    NOREF(pvUser2); NOREF(idCpu);
+}
+
+
+/**
+ * Performs some basic tests in debug builds.
+ */
+static int pgmR0DynMapTest(PVM pVM)
+{
+    LogRel(("pgmR0DynMapTest: ****** START ******\n"));
+    PPGMMAPSET      pSet  = &pVM->aCpus[0].pgm.s.AutoSet;
+    PPGMRZDYNMAP    pThis = PGMRZDYNMAP_SET_2_DYNMAP(pSet);
+    uint32_t        i;
+
+    /*
+     * Assert internal integrity first.
+     */
+    LogRel(("Test #0\n"));
+    int rc = PGMR0DynMapAssertIntegrity();
+    if (RT_FAILURE(rc))
+        return rc;
+
+    void           *pvR0DynMapUsedSaved = pVM->pgm.s.pvR0DynMapUsed;
+    pVM->pgm.s.pvR0DynMapUsed = pThis;
+    g_fPGMR0DynMapTestRunning = true;
+
+    /*
+     * Simple test, map CR3 twice and check that we're getting the
+     * same mapping address back.
+     */
+    LogRel(("Test #1\n"));
+    ASMIntDisable();
+    PGMRZDynMapStartAutoSet(&pVM->aCpus[0]);
+
+    uint64_t cr3 = ASMGetCR3() & ~(uint64_t)PAGE_OFFSET_MASK;
+    void    *pv  = (void *)(intptr_t)-1;
+    void    *pv2 = (void *)(intptr_t)-2;
+    rc           = pgmRZDynMapHCPageCommon(pVM, cr3, &pv  RTLOG_COMMA_SRC_POS);
+    int      rc2 = pgmRZDynMapHCPageCommon(pVM, cr3, &pv2 RTLOG_COMMA_SRC_POS);
+    ASMIntEnable();
+    if (    RT_SUCCESS(rc2)
+        &&  RT_SUCCESS(rc)
+        &&  pv == pv2)
+    {
+        LogRel(("Load=%u/%u/%u Set=%u/%u\n", pThis->cLoad, pThis->cMaxLoad, pThis->cPages - pThis->cPages, pSet->cEntries, RT_ELEMENTS(pSet->aEntries)));
+        rc = PGMR0DynMapAssertIntegrity();
+
+        /*
+         * Check that the simple set overflow code works by filling it
+         * with more CR3 mappings.
+         */
+        LogRel(("Test #2\n"));
+        ASMIntDisable();
+        PGMR0DynMapMigrateAutoSet(&pVM->aCpus[0]);
+        for (i = 0 ; i < UINT16_MAX*2 - 1 && RT_SUCCESS(rc) && pv2 == pv; i++)
+        {
+            pv2 = (void *)(intptr_t)-4;
+            rc = pgmRZDynMapHCPageCommon(pVM, cr3, &pv2 RTLOG_COMMA_SRC_POS);
+        }
+        ASMIntEnable();
+        if (RT_FAILURE(rc) || pv != pv2)
+        {
+            LogRel(("failed(%d): rc=%Rrc; pv=%p pv2=%p i=%p\n", __LINE__, rc, pv, pv2, i));
+            if (RT_SUCCESS(rc)) rc = VERR_PGM_DYNMAP_IPE;
+        }
+        else if (pSet->cEntries != 5)
+        {
+            LogRel(("failed(%d): cEntries=%d expected %d\n", __LINE__, pSet->cEntries, RT_ELEMENTS(pSet->aEntries) / 2));
+            rc = VERR_PGM_DYNMAP_IPE;
+        }
+        else if (   pSet->aEntries[4].cRefs != UINT16_MAX - 1
+                 || pSet->aEntries[3].cRefs != UINT16_MAX - 1
+                 || pSet->aEntries[2].cRefs != 1
+                 || pSet->aEntries[1].cRefs != 1
+                 || pSet->aEntries[0].cRefs != 1)
+        {
+            LogRel(("failed(%d): bad set dist: ", __LINE__));
+            for (i = 0; i < pSet->cEntries; i++)
+                LogRel(("[%d]=%d, ", i, pSet->aEntries[i].cRefs));
+            LogRel(("\n"));
+            rc = VERR_PGM_DYNMAP_IPE;
+        }
+        if (RT_SUCCESS(rc))
+            rc = PGMR0DynMapAssertIntegrity();
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * Trigger an set optimization run (exactly).
+             */
+            LogRel(("Test #3\n"));
+            ASMIntDisable();
+            PGMR0DynMapMigrateAutoSet(&pVM->aCpus[0]);
+            pv2 = NULL;
+            for (i = 0 ; i < RT_ELEMENTS(pSet->aEntries) - 5 && RT_SUCCESS(rc) && pv2 != pv; i++)
+            {
+                pv2 = (void *)(intptr_t)(-5 - i);
+                rc = pgmRZDynMapHCPageCommon(pVM, cr3 + PAGE_SIZE * (i + 5), &pv2 RTLOG_COMMA_SRC_POS);
+            }
+            ASMIntEnable();
+            if (RT_FAILURE(rc) || pv == pv2)
+            {
+                LogRel(("failed(%d): rc=%Rrc; pv=%p pv2=%p i=%d\n", __LINE__, rc, pv, pv2, i));
+                if (RT_SUCCESS(rc)) rc = VERR_PGM_DYNMAP_IPE;
+            }
+            else if (pSet->cEntries != RT_ELEMENTS(pSet->aEntries))
+            {
+                LogRel(("failed(%d): cEntries=%d expected %d\n", __LINE__, pSet->cEntries, RT_ELEMENTS(pSet->aEntries)));
+                rc = VERR_PGM_DYNMAP_IPE;
+            }
+            LogRel(("Load=%u/%u/%u Set=%u/%u\n", pThis->cLoad, pThis->cMaxLoad, pThis->cPages - pThis->cPages, pSet->cEntries, RT_ELEMENTS(pSet->aEntries)));
+            if (RT_SUCCESS(rc))
+                rc = PGMR0DynMapAssertIntegrity();
+            if (RT_SUCCESS(rc))
+            {
+                /*
+                 * Trigger an overflow error.
+                 */
+                LogRel(("Test #4\n"));
+                ASMIntDisable();
+                PGMR0DynMapMigrateAutoSet(&pVM->aCpus[0]);
+                for (i = 0 ; i < RT_ELEMENTS(pSet->aEntries) + 2; i++)
+                {
+                    rc = pgmRZDynMapHCPageCommon(pVM, cr3 - PAGE_SIZE * (i + 5), &pv2 RTLOG_COMMA_SRC_POS);
+                    if (RT_SUCCESS(rc))
+                        rc = PGMR0DynMapAssertIntegrity();
+                    if (RT_FAILURE(rc))
+                        break;
+                }
+                ASMIntEnable();
+                if (rc == VERR_PGM_DYNMAP_FULL_SET)
+                {
+                    /* flush the set. */
+                    LogRel(("Test #5\n"));
+                    ASMIntDisable();
+                    PGMR0DynMapMigrateAutoSet(&pVM->aCpus[0]);
+                    PGMRZDynMapReleaseAutoSet(&pVM->aCpus[0]);
+                    PGMRZDynMapStartAutoSet(&pVM->aCpus[0]);
+                    ASMIntEnable();
+
+                    rc = PGMR0DynMapAssertIntegrity();
+                }
+                else
+                {
+                    LogRel(("failed(%d): rc=%Rrc, wanted %d ; pv2=%p Set=%u/%u; i=%d\n", __LINE__,
+                            rc, VERR_PGM_DYNMAP_FULL_SET, pv2, pSet->cEntries, RT_ELEMENTS(pSet->aEntries), i));
+                    if (RT_SUCCESS(rc)) rc = VERR_PGM_DYNMAP_IPE;
+                }
+            }
+        }
+    }
+    else
+    {
+        LogRel(("failed(%d): rc=%Rrc rc2=%Rrc; pv=%p pv2=%p\n", __LINE__, rc, rc2, pv, pv2));
+        if (RT_SUCCESS(rc))
+            rc = rc2;
+    }
+
+    /*
+     * Check that everyone sees the same stuff.
+     */
+    if (RT_SUCCESS(rc))
+    {
+        LogRel(("Test #5\n"));
+        ASMIntDisable();
+        PGMR0DynMapMigrateAutoSet(&pVM->aCpus[0]);
+        RTHCPHYS  HCPhysPT = RTR0MemObjGetPagePhysAddr(pThis->pSegHead->ahMemObjPTs[0], 0);
+        rc  = pgmRZDynMapHCPageCommon(pVM, HCPhysPT, &pv RTLOG_COMMA_SRC_POS);
+        if (RT_SUCCESS(rc))
+        {
+            PGMR0DYNMAPTEST Test;
+            uint32_t       *pu32Real = &pThis->paPages[pThis->pSegHead->iPage].uPte.pLegacy->u;
+            Test.pu32       = (uint32_t *)((uintptr_t)pv | ((uintptr_t)pu32Real & PAGE_OFFSET_MASK));
+            Test.u32Expect  = *pu32Real;
+            ASMAtomicWriteU32(&Test.cFailures, 0);
+            ASMIntEnable();
+
+            rc = RTMpOnAll(pgmR0DynMapTest3PerCpu, &Test, NULL);
+            if (RT_FAILURE(rc))
+                LogRel(("failed(%d): RTMpOnAll rc=%Rrc\n", __LINE__, rc));
+            else if (Test.cFailures)
+            {
+                LogRel(("failed(%d): cFailures=%d pu32Real=%p pu32=%p u32Expect=%#x *pu32=%#x\n", __LINE__,
+                        Test.cFailures, pu32Real, Test.pu32, Test.u32Expect, *Test.pu32));
+                rc = VERR_PGM_DYNMAP_IPE;
+            }
+            else
+                LogRel(("pu32Real=%p pu32=%p u32Expect=%#x *pu32=%#x\n",
+                        pu32Real, Test.pu32, Test.u32Expect, *Test.pu32));
+        }
+        else
+        {
+            ASMIntEnable();
+            LogRel(("failed(%d): rc=%Rrc\n", rc));
+        }
+    }
+
+    /*
+     * Clean up.
+     */
+    LogRel(("Cleanup.\n"));
+    ASMIntDisable();
+    PGMR0DynMapMigrateAutoSet(&pVM->aCpus[0]);
+    PGMRZDynMapFlushAutoSet(&pVM->aCpus[0]);
+    PGMRZDynMapReleaseAutoSet(&pVM->aCpus[0]);
+    ASMIntEnable();
+
+    if (RT_SUCCESS(rc))
+        rc = PGMR0DynMapAssertIntegrity();
+    else
+        PGMR0DynMapAssertIntegrity();
+
+    g_fPGMR0DynMapTestRunning = false;
+    LogRel(("Result: rc=%Rrc Load=%u/%u/%u Set=%#x/%u\n", rc,
+            pThis->cLoad, pThis->cMaxLoad, pThis->cPages - pThis->cPages, pSet->cEntries, RT_ELEMENTS(pSet->aEntries)));
+    pVM->pgm.s.pvR0DynMapUsed = pvR0DynMapUsedSaved;
+    LogRel(("pgmR0DynMapTest: ****** END ******\n"));
+    return rc;
+}
+#endif /* DEBUG */
+