path: root/src/VBox/VMM/VMMR3/PGMPool.cpp

/* $Id: PGMPool.cpp $ */
/** @file
 * PGM Shadow Page Pool.
 */

/*
 * Copyright (C) 2006-2023 Oracle and/or its affiliates.
 *
 * This file is part of VirtualBox base platform packages, as
 * available from https://www.virtualbox.org.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation, in version 3 of the
 * License.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <https://www.gnu.org/licenses>.
 *
 * SPDX-License-Identifier: GPL-3.0-only
 */

/** @page pg_pgm_pool       PGM Shadow Page Pool
 *
 * Motivations:
 *      -# Relationship between shadow page tables and physical guest pages. This
 *         should allow us to skip most of the global flushes now following access
 *         handler changes. The main expense is flushing shadow pages.
 *      -# Limit the pool size if necessary (default is kind of limitless).
 *      -# Allocate shadow pages from RC. We use to only do this in SyncCR3.
 *      -# Required for 64-bit guests.
 *      -# Combining the PD cache and page pool in order to simplify caching.
 *
 *
 * @section sec_pgm_pool_outline    Design Outline
 *
 * The shadow page pool tracks pages used for shadowing paging structures (i.e.
 * page tables, page directory, page directory pointer table and page map
 * level-4). Each page in the pool has an unique identifier. This identifier is
 * used to link a guest physical page to a shadow PT. The identifier is a
 * non-zero value and has a relativly low max value - say 14 bits. This makes it
 * possible to fit it into the upper bits of the of the aHCPhys entries in the
 * ram range.
 *
 * By restricting host physical memory to the first 48 bits (which is the
 * announced physical memory range of the K8L chip (scheduled for 2008)), we
 * can safely use the upper 16 bits for shadow page ID and reference counting.
 *
 * Update: The 48 bit assumption will be lifted with the new physical memory
 * management (PGMPAGE), so we won't have any trouble when someone stuffs 2TB
 * into a box in some years.
 *
 * Now, it's possible for a page to be aliased, i.e. mapped by more than one PT
 * or PD. This is solved by creating a list of physical cross reference extents
 * when ever this happens. Each node in the list (extent) is can contain 3 page
 * pool indexes. The list it self is chained using indexes into the paPhysExt
 * array.
 *
 *
 * @section sec_pgm_pool_life       Life Cycle of a Shadow Page
 *
 * -# The SyncPT function requests a page from the pool.
 *    The request includes the kind of page it is (PT/PD, PAE/legacy), the
 *    address of the page it's shadowing, and more.
 * -# The pool responds to the request by allocating a new page.
 *    When the cache is enabled, it will first check if it's in the cache.
 *    Should the pool be exhausted, one of two things can be done:
 *      -# Flush the whole pool and current CR3.
 *      -# Use the cache to find a page which can be flushed (~age).
 * -# The SyncPT function will sync one or more pages and insert it into the
 *    shadow PD.
 * -# The SyncPage function may sync more pages on a later \#PFs.
 * -# The page is freed / flushed in SyncCR3 (perhaps) and some other cases.
 *    When caching is enabled, the page isn't flush but remains in the cache.
 *
 *
 * @section sec_pgm_pool_monitoring Monitoring
 *
 * We always monitor GUEST_PAGE_SIZE chunks of memory. When we've got multiple
 * shadow pages for the same GUEST_PAGE_SIZE of guest memory (PAE and mixed
 * PD/PT) the pages sharing the monitor get linked using the
 * iMonitoredNext/Prev. The head page is the pvUser to the access handlers.
 *
 *
 * @section sec_pgm_pool_impl       Implementation
 *
 * The pool will take pages from the MM page pool. The tracking data
 * (attributes, bitmaps and so on) are allocated from the hypervisor heap. The
 * pool content can be accessed both by using the page id and the physical
 * address (HC). The former is managed by means of an array, the latter by an
 * offset based AVL tree.
 *
 * Flushing of a pool page means that we iterate the content (we know what kind
 * it is) and updates the link information in the ram range.
 *
 * ...
 */


/*********************************************************************************************************************************
*   Header Files                                                                                                                 *
*********************************************************************************************************************************/
#define LOG_GROUP LOG_GROUP_PGM_POOL
#define VBOX_WITHOUT_PAGING_BIT_FIELDS /* 64-bit bitfields are just asking for trouble. See @bugref{9841} and others. */
#include <VBox/vmm/pgm.h>
#include <VBox/vmm/mm.h>
#include "PGMInternal.h"
#include <VBox/vmm/vmcc.h>
#include <VBox/vmm/uvm.h>
#include "PGMInline.h"

#include <VBox/log.h>
#include <VBox/err.h>
#include <iprt/asm.h>
#include <iprt/string.h>
#include <VBox/dbg.h>


/*********************************************************************************************************************************
*   Structures and Typedefs                                                                                                      *
*********************************************************************************************************************************/
typedef struct PGMPOOLCHECKERSTATE
{
    PDBGCCMDHLP     pCmdHlp;
    PVM             pVM;
    PPGMPOOL        pPool;
    PPGMPOOLPAGE    pPage;
    bool            fFirstMsg;
    uint32_t        cErrors;
} PGMPOOLCHECKERSTATE;
typedef PGMPOOLCHECKERSTATE *PPGMPOOLCHECKERSTATE;



/*********************************************************************************************************************************
*   Internal Functions                                                                                                           *
*********************************************************************************************************************************/
static FNDBGFHANDLERINT pgmR3PoolInfoPages;
static FNDBGFHANDLERINT pgmR3PoolInfoRoots;

#ifdef VBOX_WITH_DEBUGGER
static FNDBGCCMD pgmR3PoolCmdCheck;

/** Command descriptors. */
static const DBGCCMD    g_aCmds[] =
{
    /* pszCmd,  cArgsMin, cArgsMax, paArgDesc, cArgDescs, fFlags, pfnHandler          pszSyntax,  ....pszDescription */
    { "pgmpoolcheck",  0, 0,        NULL,      0,         0,      pgmR3PoolCmdCheck,  "",         "Check the pgm pool pages." },
};
#endif

/**
 * Initializes the pool
 *
 * @returns VBox status code.
 * @param   pVM     The cross context VM structure.
 */
int pgmR3PoolInit(PVM pVM)
{
    int rc;

    AssertCompile(NIL_PGMPOOL_IDX == 0);
    /* pPage->cLocked is an unsigned byte. */
    AssertCompile(VMM_MAX_CPU_COUNT <= 255);

    /*
     * Query Pool config.
     */
    PCFGMNODE pCfg = CFGMR3GetChild(CFGMR3GetRoot(pVM), "/PGM/Pool");

    /* Default pgm pool size is 1024 pages (4MB). */
    uint16_t cMaxPages = 1024;

    /* Adjust it up relative to the RAM size, using the nested paging formula. */
    uint64_t cbRam;
    rc = CFGMR3QueryU64Def(CFGMR3GetRoot(pVM), "RamSize", &cbRam, 0); AssertRCReturn(rc, rc);
    /** @todo guest x86 specific */
    uint64_t u64MaxPages = (cbRam >> 9)
                         + (cbRam >> 18)
                         + (cbRam >> 27)
                         + 32 * GUEST_PAGE_SIZE;
    u64MaxPages >>= GUEST_PAGE_SHIFT;
    if (u64MaxPages > PGMPOOL_IDX_LAST)
        cMaxPages = PGMPOOL_IDX_LAST;
    else
        cMaxPages = (uint16_t)u64MaxPages;

    /** @cfgm{/PGM/Pool/MaxPages, uint16_t, \#pages, 16, 0x3fff, F(ram-size)}
     * The max size of the shadow page pool in pages. The pool will grow dynamically
     * up to this limit.
     */
    rc = CFGMR3QueryU16Def(pCfg, "MaxPages", &cMaxPages, cMaxPages);
    AssertLogRelRCReturn(rc, rc);
    AssertLogRelMsgReturn(cMaxPages <= PGMPOOL_IDX_LAST && cMaxPages >= RT_ALIGN(PGMPOOL_IDX_FIRST, 16),
                          ("cMaxPages=%u (%#x)\n", cMaxPages, cMaxPages), VERR_INVALID_PARAMETER);
    AssertCompile(RT_IS_POWER_OF_TWO(PGMPOOL_CFG_MAX_GROW));
    if (cMaxPages < PGMPOOL_IDX_LAST)
        cMaxPages = RT_ALIGN(cMaxPages, PGMPOOL_CFG_MAX_GROW / 2);
    if (cMaxPages > PGMPOOL_IDX_LAST)
        cMaxPages = PGMPOOL_IDX_LAST;
    LogRel(("PGM: PGMPool: cMaxPages=%u (u64MaxPages=%llu)\n", cMaxPages, u64MaxPages));

    /** @todo
     * We need to be much more careful with our allocation strategy here.
     * For nested paging we don't need pool user info nor extents at all, but
     * we can't check for nested paging here (too early during init to get a
     * confirmation it can be used).  The default for large memory configs is a
     * bit large for shadow paging, so I've restricted the extent maximum to 8k
     * (8k * 16 = 128k of hyper heap).
     *
     * Also when large page support is enabled, we typically don't need so much,
     * although that depends on the availability of 2 MB chunks on the host.
     */

    /** @cfgm{/PGM/Pool/MaxUsers, uint16_t, \#users, MaxUsers, 32K, MaxPages*2}
     * The max number of shadow page user tracking records. Each shadow page has
     * zero of other shadow pages (or CR3s) that references it, or uses it if you
     * like. The structures describing these relationships are allocated from a
     * fixed sized pool. This configuration variable defines the pool size.
     */
    uint16_t cMaxUsers;
    rc = CFGMR3QueryU16Def(pCfg, "MaxUsers", &cMaxUsers, cMaxPages * 2);
    AssertLogRelRCReturn(rc, rc);
    AssertLogRelMsgReturn(cMaxUsers >= cMaxPages && cMaxPages <= _32K,
                          ("cMaxUsers=%u (%#x)\n", cMaxUsers, cMaxUsers), VERR_INVALID_PARAMETER);

    /** @cfgm{/PGM/Pool/MaxPhysExts, uint16_t, \#extents, 16, MaxPages * 2, MIN(MaxPages*2\,8192)}
     * The max number of extents for tracking aliased guest pages.
     */
    uint16_t cMaxPhysExts;
    rc = CFGMR3QueryU16Def(pCfg, "MaxPhysExts", &cMaxPhysExts,
                           RT_MIN(cMaxPages * 2, 8192 /* 8Ki max as this eat too much hyper heap */));
    AssertLogRelRCReturn(rc, rc);
    AssertLogRelMsgReturn(cMaxPhysExts >= 16 && cMaxPhysExts <= PGMPOOL_IDX_LAST,
                          ("cMaxPhysExts=%u (%#x)\n", cMaxPhysExts, cMaxPhysExts), VERR_INVALID_PARAMETER);

    /** @cfgm{/PGM/Pool/ChacheEnabled, bool, true}
     * Enables or disabling caching of shadow pages. Caching means that we will try
     * reuse shadow pages instead of recreating them everything SyncCR3, SyncPT or
     * SyncPage requests one. When reusing a shadow page, we can save time
     * reconstructing it and it's children.
     */
    bool fCacheEnabled;
    rc = CFGMR3QueryBoolDef(pCfg, "CacheEnabled", &fCacheEnabled, true);
    AssertLogRelRCReturn(rc, rc);

    LogRel(("PGM: pgmR3PoolInit: cMaxPages=%#RX16 cMaxUsers=%#RX16 cMaxPhysExts=%#RX16 fCacheEnable=%RTbool\n",
             cMaxPages, cMaxUsers, cMaxPhysExts, fCacheEnabled));

    /*
     * Allocate the data structures.
     */
    uint32_t cb = RT_UOFFSETOF_DYN(PGMPOOL, aPages[cMaxPages]);
    cb += cMaxUsers * sizeof(PGMPOOLUSER);
    cb += cMaxPhysExts * sizeof(PGMPOOLPHYSEXT);
    PPGMPOOL pPool;
    RTR0PTR  pPoolR0;
    rc = SUPR3PageAllocEx(RT_ALIGN_32(cb, HOST_PAGE_SIZE) >> HOST_PAGE_SHIFT, 0 /*fFlags*/, (void **)&pPool, &pPoolR0, NULL);
    if (RT_FAILURE(rc))
        return rc;
    Assert(ASMMemIsZero(pPool, cb));
    pVM->pgm.s.pPoolR3 = pPool->pPoolR3 = pPool;
    pVM->pgm.s.pPoolR0 = pPool->pPoolR0 = pPoolR0;

    /*
     * Initialize it.
     */
    pPool->pVMR3     = pVM;
    pPool->pVMR0     = pVM->pVMR0ForCall;
    pPool->cMaxPages = cMaxPages;
    pPool->cCurPages = PGMPOOL_IDX_FIRST;
    pPool->iUserFreeHead = 0;
    pPool->cMaxUsers = cMaxUsers;
    PPGMPOOLUSER paUsers = (PPGMPOOLUSER)&pPool->aPages[pPool->cMaxPages];
    pPool->paUsersR3 = paUsers;
    pPool->paUsersR0 = pPoolR0 + (uintptr_t)paUsers - (uintptr_t)pPool;
    for (unsigned i = 0; i < cMaxUsers; i++)
    {
        paUsers[i].iNext = i + 1;
        paUsers[i].iUser = NIL_PGMPOOL_IDX;
        paUsers[i].iUserTable = 0xfffffffe;
    }
    paUsers[cMaxUsers - 1].iNext = NIL_PGMPOOL_USER_INDEX;
    pPool->iPhysExtFreeHead = 0;
    pPool->cMaxPhysExts = cMaxPhysExts;
    PPGMPOOLPHYSEXT paPhysExts = (PPGMPOOLPHYSEXT)&paUsers[cMaxUsers];
    pPool->paPhysExtsR3 = paPhysExts;
    pPool->paPhysExtsR0 = pPoolR0 + (uintptr_t)paPhysExts - (uintptr_t)pPool;
    for (unsigned i = 0; i < cMaxPhysExts; i++)
    {
        paPhysExts[i].iNext = i + 1;
        paPhysExts[i].aidx[0] = NIL_PGMPOOL_IDX;
        paPhysExts[i].apte[0] = NIL_PGMPOOL_PHYSEXT_IDX_PTE;
        paPhysExts[i].aidx[1] = NIL_PGMPOOL_IDX;
        paPhysExts[i].apte[1] = NIL_PGMPOOL_PHYSEXT_IDX_PTE;
        paPhysExts[i].aidx[2] = NIL_PGMPOOL_IDX;
        paPhysExts[i].apte[2] = NIL_PGMPOOL_PHYSEXT_IDX_PTE;
    }
    paPhysExts[cMaxPhysExts - 1].iNext = NIL_PGMPOOL_PHYSEXT_INDEX;
    for (unsigned i = 0; i < RT_ELEMENTS(pPool->aiHash); i++)
        pPool->aiHash[i] = NIL_PGMPOOL_IDX;
    pPool->iAgeHead = NIL_PGMPOOL_IDX;
    pPool->iAgeTail = NIL_PGMPOOL_IDX;
    pPool->fCacheEnabled = fCacheEnabled;

    pPool->hAccessHandlerType = NIL_PGMPHYSHANDLERTYPE;
    rc = PGMR3HandlerPhysicalTypeRegister(pVM, PGMPHYSHANDLERKIND_WRITE, PGMPHYSHANDLER_F_KEEP_PGM_LOCK,
                                          pgmPoolAccessHandler, "Guest Paging Access Handler", &pPool->hAccessHandlerType);
    AssertLogRelRCReturn(rc, rc);

    pPool->HCPhysTree = 0;

    /*
     * The NIL entry.
     */
    Assert(NIL_PGMPOOL_IDX == 0);
    pPool->aPages[NIL_PGMPOOL_IDX].enmKind          = PGMPOOLKIND_INVALID;
    pPool->aPages[NIL_PGMPOOL_IDX].idx              = NIL_PGMPOOL_IDX;
    pPool->aPages[NIL_PGMPOOL_IDX].Core.Key         = NIL_RTHCPHYS;
    pPool->aPages[NIL_PGMPOOL_IDX].GCPhys           = NIL_RTGCPHYS;
    pPool->aPages[NIL_PGMPOOL_IDX].iNext            = NIL_PGMPOOL_IDX;
    /* pPool->aPages[NIL_PGMPOOL_IDX].cLocked          = INT32_MAX; - test this out... */
    pPool->aPages[NIL_PGMPOOL_IDX].pvPageR3         = 0;
    pPool->aPages[NIL_PGMPOOL_IDX].iUserHead        = NIL_PGMPOOL_USER_INDEX;
    pPool->aPages[NIL_PGMPOOL_IDX].iModifiedNext    = NIL_PGMPOOL_IDX;
    pPool->aPages[NIL_PGMPOOL_IDX].iModifiedPrev    = NIL_PGMPOOL_IDX;
    pPool->aPages[NIL_PGMPOOL_IDX].iMonitoredNext   = NIL_PGMPOOL_IDX;
    pPool->aPages[NIL_PGMPOOL_IDX].iMonitoredPrev   = NIL_PGMPOOL_IDX;
    pPool->aPages[NIL_PGMPOOL_IDX].iAgeNext         = NIL_PGMPOOL_IDX;
    pPool->aPages[NIL_PGMPOOL_IDX].iAgePrev         = NIL_PGMPOOL_IDX;

    Assert(pPool->aPages[NIL_PGMPOOL_IDX].idx == NIL_PGMPOOL_IDX);
    Assert(pPool->aPages[NIL_PGMPOOL_IDX].GCPhys == NIL_RTGCPHYS);
    Assert(!pPool->aPages[NIL_PGMPOOL_IDX].fSeenNonGlobal);
    Assert(!pPool->aPages[NIL_PGMPOOL_IDX].fMonitored);
    Assert(!pPool->aPages[NIL_PGMPOOL_IDX].fCached);
    Assert(!pPool->aPages[NIL_PGMPOOL_IDX].fZeroed);
    Assert(!pPool->aPages[NIL_PGMPOOL_IDX].fReusedFlushPending);

    /*
     * Register statistics.
     */
    STAM_REL_REG(pVM, &pPool->StatGrow,                 STAMTYPE_PROFILE,   "/PGM/Pool/Grow",           STAMUNIT_TICKS_PER_CALL,    "Profiling PGMR0PoolGrow");
#ifdef VBOX_WITH_STATISTICS
    STAM_REG(pVM, &pPool->cCurPages,                    STAMTYPE_U16,       "/PGM/Pool/cCurPages",      STAMUNIT_PAGES,             "Current pool size.");
    STAM_REG(pVM, &pPool->cMaxPages,                    STAMTYPE_U16,       "/PGM/Pool/cMaxPages",      STAMUNIT_PAGES,             "Max pool size.");
    STAM_REG(pVM, &pPool->cUsedPages,                   STAMTYPE_U16,       "/PGM/Pool/cUsedPages",     STAMUNIT_PAGES,             "The number of pages currently in use.");
    STAM_REG(pVM, &pPool->cUsedPagesHigh,               STAMTYPE_U16_RESET, "/PGM/Pool/cUsedPagesHigh", STAMUNIT_PAGES,             "The high watermark for cUsedPages.");
    STAM_REG(pVM, &pPool->StatAlloc,                  STAMTYPE_PROFILE_ADV, "/PGM/Pool/Alloc",          STAMUNIT_TICKS_PER_CALL,    "Profiling of pgmPoolAlloc.");
    STAM_REG(pVM, &pPool->StatClearAll,                 STAMTYPE_PROFILE,   "/PGM/Pool/ClearAll",       STAMUNIT_TICKS_PER_CALL,    "Profiling of pgmR3PoolClearAll.");
    STAM_REG(pVM, &pPool->StatR3Reset,                  STAMTYPE_PROFILE,   "/PGM/Pool/R3Reset",        STAMUNIT_TICKS_PER_CALL,    "Profiling of pgmR3PoolReset.");
    STAM_REG(pVM, &pPool->StatFlushPage,                STAMTYPE_PROFILE,   "/PGM/Pool/FlushPage",      STAMUNIT_TICKS_PER_CALL,    "Profiling of pgmPoolFlushPage.");
    STAM_REG(pVM, &pPool->StatFree,                     STAMTYPE_PROFILE,   "/PGM/Pool/Free",           STAMUNIT_TICKS_PER_CALL,    "Profiling of pgmPoolFree.");
    STAM_REG(pVM, &pPool->StatForceFlushPage,           STAMTYPE_COUNTER,   "/PGM/Pool/FlushForce",     STAMUNIT_OCCURENCES,        "Counting explicit flushes by PGMPoolFlushPage().");
    STAM_REG(pVM, &pPool->StatForceFlushDirtyPage,      STAMTYPE_COUNTER,   "/PGM/Pool/FlushForceDirty",     STAMUNIT_OCCURENCES,   "Counting explicit flushes of dirty pages by PGMPoolFlushPage().");
    STAM_REG(pVM, &pPool->StatForceFlushReused,         STAMTYPE_COUNTER,   "/PGM/Pool/FlushReused",    STAMUNIT_OCCURENCES,        "Counting flushes for reused pages.");
    STAM_REG(pVM, &pPool->StatZeroPage,                 STAMTYPE_PROFILE,   "/PGM/Pool/ZeroPage",       STAMUNIT_TICKS_PER_CALL,    "Profiling time spent zeroing pages. Overlaps with Alloc.");
    STAM_REG(pVM, &pPool->cMaxUsers,                    STAMTYPE_U16,       "/PGM/Pool/Track/cMaxUsers",            STAMUNIT_COUNT,      "Max user tracking records.");
    STAM_REG(pVM, &pPool->cPresent,                     STAMTYPE_U32,       "/PGM/Pool/Track/cPresent",             STAMUNIT_COUNT,      "Number of present page table entries.");
    STAM_REG(pVM, &pPool->StatTrackDeref,               STAMTYPE_PROFILE,   "/PGM/Pool/Track/Deref",                STAMUNIT_TICKS_PER_CALL, "Profiling of pgmPoolTrackDeref.");
    STAM_REG(pVM, &pPool->StatTrackFlushGCPhysPT,       STAMTYPE_PROFILE,   "/PGM/Pool/Track/FlushGCPhysPT",        STAMUNIT_TICKS_PER_CALL, "Profiling of pgmPoolTrackFlushGCPhysPT.");
    STAM_REG(pVM, &pPool->StatTrackFlushGCPhysPTs,      STAMTYPE_PROFILE,   "/PGM/Pool/Track/FlushGCPhysPTs",       STAMUNIT_TICKS_PER_CALL, "Profiling of pgmPoolTrackFlushGCPhysPTs.");
    STAM_REG(pVM, &pPool->StatTrackFlushGCPhysPTsSlow,  STAMTYPE_PROFILE,   "/PGM/Pool/Track/FlushGCPhysPTsSlow",   STAMUNIT_TICKS_PER_CALL, "Profiling of pgmPoolTrackFlushGCPhysPTsSlow.");
    STAM_REG(pVM, &pPool->StatTrackFlushEntry,          STAMTYPE_COUNTER,   "/PGM/Pool/Track/Entry/Flush",          STAMUNIT_COUNT,          "Nr of flushed entries.");
    STAM_REG(pVM, &pPool->StatTrackFlushEntryKeep,      STAMTYPE_COUNTER,   "/PGM/Pool/Track/Entry/Update",         STAMUNIT_COUNT,          "Nr of updated entries.");
    STAM_REG(pVM, &pPool->StatTrackFreeUpOneUser,       STAMTYPE_COUNTER,   "/PGM/Pool/Track/FreeUpOneUser",        STAMUNIT_TICKS_PER_CALL, "The number of times we were out of user tracking records.");
    STAM_REG(pVM, &pPool->StatTrackDerefGCPhys,         STAMTYPE_PROFILE,   "/PGM/Pool/Track/DrefGCPhys",           STAMUNIT_TICKS_PER_CALL, "Profiling deref activity related tracking GC physical pages.");
    STAM_REG(pVM, &pPool->StatTrackLinearRamSearches,   STAMTYPE_COUNTER,   "/PGM/Pool/Track/LinearRamSearches",    STAMUNIT_OCCURENCES, "The number of times we had to do linear ram searches.");
    STAM_REG(pVM, &pPool->StamTrackPhysExtAllocFailures,STAMTYPE_COUNTER,   "/PGM/Pool/Track/PhysExtAllocFailures", STAMUNIT_OCCURENCES, "The number of failing pgmPoolTrackPhysExtAlloc calls.");

    STAM_REG(pVM, &pPool->StatMonitorPfRZ,                STAMTYPE_PROFILE, "/PGM/Pool/Monitor/RZ/#PF",                 STAMUNIT_TICKS_PER_CALL, "Profiling the RC/R0 #PF access handler.");
    STAM_REG(pVM, &pPool->StatMonitorPfRZEmulateInstr,    STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/#PF/EmulateInstr",    STAMUNIT_OCCURENCES,     "Times we've failed interpreting the instruction.");
    STAM_REG(pVM, &pPool->StatMonitorPfRZFlushPage,       STAMTYPE_PROFILE, "/PGM/Pool/Monitor/RZ/#PF/FlushPage",       STAMUNIT_TICKS_PER_CALL, "Profiling the pgmPoolFlushPage calls made from the RC/R0 access handler.");
    STAM_REG(pVM, &pPool->StatMonitorPfRZFlushReinit,     STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/#PF/FlushReinit",     STAMUNIT_OCCURENCES,     "Times we've detected a page table reinit.");
    STAM_REG(pVM, &pPool->StatMonitorPfRZFlushModOverflow,STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/#PF/FlushOverflow",   STAMUNIT_OCCURENCES,     "Counting flushes for pages that are modified too often.");
    STAM_REG(pVM, &pPool->StatMonitorPfRZFork,            STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/#PF/Fork",            STAMUNIT_OCCURENCES,     "Times we've detected fork().");
    STAM_REG(pVM, &pPool->StatMonitorPfRZHandled,         STAMTYPE_PROFILE, "/PGM/Pool/Monitor/RZ/#PF/Handled",         STAMUNIT_TICKS_PER_CALL, "Profiling the RC/R0 #PF access we've handled (except REP STOSD).");
    STAM_REG(pVM, &pPool->StatMonitorPfRZIntrFailPatch1,  STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/#PF/IntrFailPatch1",  STAMUNIT_OCCURENCES,     "Times we've failed interpreting a patch code instruction.");
    STAM_REG(pVM, &pPool->StatMonitorPfRZIntrFailPatch2,  STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/#PF/IntrFailPatch2",  STAMUNIT_OCCURENCES,     "Times we've failed interpreting a patch code instruction during flushing.");
    STAM_REG(pVM, &pPool->StatMonitorPfRZRepPrefix,       STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/#PF/RepPrefix",       STAMUNIT_OCCURENCES,     "The number of times we've seen rep prefixes we can't handle.");
    STAM_REG(pVM, &pPool->StatMonitorPfRZRepStosd,        STAMTYPE_PROFILE, "/PGM/Pool/Monitor/RZ/#PF/RepStosd",        STAMUNIT_TICKS_PER_CALL, "Profiling the REP STOSD cases we've handled.");

    STAM_REG(pVM, &pPool->StatMonitorRZ,                  STAMTYPE_PROFILE, "/PGM/Pool/Monitor/RZ/IEM",                 STAMUNIT_TICKS_PER_CALL, "Profiling the regular access handler.");
    STAM_REG(pVM, &pPool->StatMonitorRZFlushPage,         STAMTYPE_PROFILE, "/PGM/Pool/Monitor/RZ/IEM/FlushPage",       STAMUNIT_TICKS_PER_CALL, "Profiling the pgmPoolFlushPage calls made from the regular access handler.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[0],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size01",          STAMUNIT_OCCURENCES,     "Number of 1 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[1],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size02",          STAMUNIT_OCCURENCES,     "Number of 2 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[2],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size03",          STAMUNIT_OCCURENCES,     "Number of 3 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[3],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size04",          STAMUNIT_OCCURENCES,     "Number of 4 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[4],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size05",          STAMUNIT_OCCURENCES,     "Number of 5 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[5],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size06",          STAMUNIT_OCCURENCES,     "Number of 6 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[6],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size07",          STAMUNIT_OCCURENCES,     "Number of 7 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[7],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size08",          STAMUNIT_OCCURENCES,     "Number of 8 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[8],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size09",          STAMUNIT_OCCURENCES,     "Number of 9 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[9],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size0a",          STAMUNIT_OCCURENCES,     "Number of 10 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[10],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size0b",          STAMUNIT_OCCURENCES,     "Number of 11 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[11],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size0c",          STAMUNIT_OCCURENCES,     "Number of 12 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[12],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size0d",          STAMUNIT_OCCURENCES,     "Number of 13 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[13],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size0e",          STAMUNIT_OCCURENCES,     "Number of 14 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[14],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size0f",          STAMUNIT_OCCURENCES,     "Number of 15 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[15],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size10",          STAMUNIT_OCCURENCES,     "Number of 16 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[16],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size11-2f",       STAMUNIT_OCCURENCES,     "Number of 17-31 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[17],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size20-3f",       STAMUNIT_OCCURENCES,     "Number of 32-63 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZSizes[18],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Size40+",         STAMUNIT_OCCURENCES,     "Number of 64+ byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorRZMisaligned[0],    STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Misaligned1",     STAMUNIT_OCCURENCES,     "Number of misaligned access with offset 1.");
    STAM_REG(pVM, &pPool->aStatMonitorRZMisaligned[1],    STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Misaligned2",     STAMUNIT_OCCURENCES,     "Number of misaligned access with offset 2.");
    STAM_REG(pVM, &pPool->aStatMonitorRZMisaligned[2],    STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Misaligned3",     STAMUNIT_OCCURENCES,     "Number of misaligned access with offset 3.");
    STAM_REG(pVM, &pPool->aStatMonitorRZMisaligned[3],    STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Misaligned4",     STAMUNIT_OCCURENCES,     "Number of misaligned access with offset 4.");
    STAM_REG(pVM, &pPool->aStatMonitorRZMisaligned[4],    STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Misaligned5",     STAMUNIT_OCCURENCES,     "Number of misaligned access with offset 5.");
    STAM_REG(pVM, &pPool->aStatMonitorRZMisaligned[5],    STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Misaligned6",     STAMUNIT_OCCURENCES,     "Number of misaligned access with offset 6.");
    STAM_REG(pVM, &pPool->aStatMonitorRZMisaligned[6],    STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/IEM/Misaligned7",     STAMUNIT_OCCURENCES,     "Number of misaligned access with offset 7.");

    STAM_REG(pVM, &pPool->StatMonitorRZFaultPT,           STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/Fault/PT",            STAMUNIT_OCCURENCES,     "Nr of handled PT faults.");
    STAM_REG(pVM, &pPool->StatMonitorRZFaultPD,           STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/Fault/PD",            STAMUNIT_OCCURENCES,     "Nr of handled PD faults.");
    STAM_REG(pVM, &pPool->StatMonitorRZFaultPDPT,         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/Fault/PDPT",          STAMUNIT_OCCURENCES,     "Nr of handled PDPT faults.");
    STAM_REG(pVM, &pPool->StatMonitorRZFaultPML4,         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/RZ/Fault/PML4",          STAMUNIT_OCCURENCES,     "Nr of handled PML4 faults.");

    STAM_REG(pVM, &pPool->StatMonitorR3,                  STAMTYPE_PROFILE, "/PGM/Pool/Monitor/R3",                     STAMUNIT_TICKS_PER_CALL, "Profiling the R3 access handler.");
    STAM_REG(pVM, &pPool->StatMonitorR3FlushPage,         STAMTYPE_PROFILE, "/PGM/Pool/Monitor/R3/FlushPage",           STAMUNIT_TICKS_PER_CALL, "Profiling the pgmPoolFlushPage calls made from the R3 access handler.");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[0],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size01",              STAMUNIT_OCCURENCES,     "Number of 1 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[1],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size02",              STAMUNIT_OCCURENCES,     "Number of 2 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[2],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size03",              STAMUNIT_OCCURENCES,     "Number of 3 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[3],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size04",              STAMUNIT_OCCURENCES,     "Number of 4 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[4],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size05",              STAMUNIT_OCCURENCES,     "Number of 5 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[5],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size06",              STAMUNIT_OCCURENCES,     "Number of 6 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[6],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size07",              STAMUNIT_OCCURENCES,     "Number of 7 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[7],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size08",              STAMUNIT_OCCURENCES,     "Number of 8 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[8],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size09",              STAMUNIT_OCCURENCES,     "Number of 9 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[9],         STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size0a",              STAMUNIT_OCCURENCES,     "Number of 10 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[10],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size0b",              STAMUNIT_OCCURENCES,     "Number of 11 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[11],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size0c",              STAMUNIT_OCCURENCES,     "Number of 12 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[12],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size0d",              STAMUNIT_OCCURENCES,     "Number of 13 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[13],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size0e",              STAMUNIT_OCCURENCES,     "Number of 14 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[14],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size0f",              STAMUNIT_OCCURENCES,     "Number of 15 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[15],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size10",              STAMUNIT_OCCURENCES,     "Number of 16 byte accesses (R3).");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[16],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size11-2f",           STAMUNIT_OCCURENCES,     "Number of 17-31 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[17],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size20-3f",           STAMUNIT_OCCURENCES,     "Number of 32-63 byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorR3Sizes[18],        STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Size40+",             STAMUNIT_OCCURENCES,     "Number of 64+ byte accesses.");
    STAM_REG(pVM, &pPool->aStatMonitorR3Misaligned[0],    STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Misaligned1",         STAMUNIT_OCCURENCES,     "Number of misaligned access with offset 1 in R3.");
    STAM_REG(pVM, &pPool->aStatMonitorR3Misaligned[1],    STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Misaligned2",         STAMUNIT_OCCURENCES,     "Number of misaligned access with offset 2 in R3.");
    STAM_REG(pVM, &pPool->aStatMonitorR3Misaligned[2],    STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Misaligned3",         STAMUNIT_OCCURENCES,     "Number of misaligned access with offset 3 in R3.");
    STAM_REG(pVM, &pPool->aStatMonitorR3Misaligned[3],    STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Misaligned4",         STAMUNIT_OCCURENCES,     "Number of misaligned access with offset 4 in R3.");
    STAM_REG(pVM, &pPool->aStatMonitorR3Misaligned[4],    STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Misaligned5",         STAMUNIT_OCCURENCES,     "Number of misaligned access with offset 5 in R3.");
    STAM_REG(pVM, &pPool->aStatMonitorR3Misaligned[5],    STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Misaligned6",         STAMUNIT_OCCURENCES,     "Number of misaligned access with offset 6 in R3.");
    STAM_REG(pVM, &pPool->aStatMonitorR3Misaligned[6],    STAMTYPE_COUNTER, "/PGM/Pool/Monitor/R3/Misaligned7",         STAMUNIT_OCCURENCES,     "Number of misaligned access with offset 7 in R3.");

    STAM_REG(pVM, &pPool->StatMonitorR3FaultPT,         STAMTYPE_COUNTER,   "/PGM/Pool/Monitor/R3/Fault/PT",        STAMUNIT_OCCURENCES,     "Nr of handled PT faults.");
    STAM_REG(pVM, &pPool->StatMonitorR3FaultPD,         STAMTYPE_COUNTER,   "/PGM/Pool/Monitor/R3/Fault/PD",        STAMUNIT_OCCURENCES,     "Nr of handled PD faults.");
    STAM_REG(pVM, &pPool->StatMonitorR3FaultPDPT,       STAMTYPE_COUNTER,   "/PGM/Pool/Monitor/R3/Fault/PDPT",      STAMUNIT_OCCURENCES,     "Nr of handled PDPT faults.");
    STAM_REG(pVM, &pPool->StatMonitorR3FaultPML4,       STAMTYPE_COUNTER,   "/PGM/Pool/Monitor/R3/Fault/PML4",      STAMUNIT_OCCURENCES,     "Nr of handled PML4 faults.");

    STAM_REG(pVM, &pPool->cModifiedPages,               STAMTYPE_U16,       "/PGM/Pool/Monitor/cModifiedPages",     STAMUNIT_PAGES,          "The current cModifiedPages value.");
    STAM_REG(pVM, &pPool->cModifiedPagesHigh,           STAMTYPE_U16_RESET, "/PGM/Pool/Monitor/cModifiedPagesHigh", STAMUNIT_PAGES,          "The high watermark for cModifiedPages.");
    STAM_REG(pVM, &pPool->StatResetDirtyPages,          STAMTYPE_COUNTER,   "/PGM/Pool/Monitor/Dirty/Resets",       STAMUNIT_OCCURENCES,     "Times we've called pgmPoolResetDirtyPages (and there were dirty page).");
    STAM_REG(pVM, &pPool->StatDirtyPage,                STAMTYPE_COUNTER,   "/PGM/Pool/Monitor/Dirty/Pages",        STAMUNIT_OCCURENCES,     "Times we've called pgmPoolAddDirtyPage.");
    STAM_REG(pVM, &pPool->StatDirtyPageDupFlush,        STAMTYPE_COUNTER,   "/PGM/Pool/Monitor/Dirty/FlushDup",     STAMUNIT_OCCURENCES,     "Times we've had to flush duplicates for dirty page management.");
    STAM_REG(pVM, &pPool->StatDirtyPageOverFlowFlush,   STAMTYPE_COUNTER,   "/PGM/Pool/Monitor/Dirty/FlushOverflow",STAMUNIT_OCCURENCES,     "Times we've had to flush because of overflow.");
    STAM_REG(pVM, &pPool->StatCacheHits,                STAMTYPE_COUNTER,   "/PGM/Pool/Cache/Hits",                 STAMUNIT_OCCURENCES, "The number of pgmPoolAlloc calls satisfied by the cache.");
    STAM_REG(pVM, &pPool->StatCacheMisses,              STAMTYPE_COUNTER,   "/PGM/Pool/Cache/Misses",               STAMUNIT_OCCURENCES, "The number of pgmPoolAlloc calls not statisfied by the cache.");
    STAM_REG(pVM, &pPool->StatCacheKindMismatches,      STAMTYPE_COUNTER,   "/PGM/Pool/Cache/KindMismatches",       STAMUNIT_OCCURENCES, "The number of shadow page kind mismatches. (Better be low, preferably 0!)");
    STAM_REG(pVM, &pPool->StatCacheFreeUpOne,           STAMTYPE_COUNTER,   "/PGM/Pool/Cache/FreeUpOne",            STAMUNIT_OCCURENCES, "The number of times the cache was asked to free up a page.");
    STAM_REG(pVM, &pPool->StatCacheCacheable,           STAMTYPE_COUNTER,   "/PGM/Pool/Cache/Cacheable",            STAMUNIT_OCCURENCES, "The number of cacheable allocations.");
    STAM_REG(pVM, &pPool->StatCacheUncacheable,         STAMTYPE_COUNTER,   "/PGM/Pool/Cache/Uncacheable",          STAMUNIT_OCCURENCES, "The number of uncacheable allocations.");
#endif /* VBOX_WITH_STATISTICS */

    DBGFR3InfoRegisterInternalEx(pVM, "pgmpoolpages", "Lists page pool pages.", pgmR3PoolInfoPages, 0);
    DBGFR3InfoRegisterInternalEx(pVM, "pgmpoolroots", "Lists page pool roots.", pgmR3PoolInfoRoots, 0);

#ifdef VBOX_WITH_DEBUGGER
    /*
     * Debugger commands.
     */
    static bool s_fRegisteredCmds = false;
    if (!s_fRegisteredCmds)
    {
        rc = DBGCRegisterCommands(&g_aCmds[0], RT_ELEMENTS(g_aCmds));
        if (RT_SUCCESS(rc))
            s_fRegisteredCmds = true;
    }
#endif

    return VINF_SUCCESS;
}


/**
 * Relocate the page pool data.
 *
 * @param   pVM     The cross context VM structure.
 */
void pgmR3PoolRelocate(PVM pVM)
{
    RT_NOREF(pVM);
}


/**
 * Grows the shadow page pool.
 *
 * I.e. adds more pages to it, assuming that hasn't reached cMaxPages yet.
 *
 * @returns VBox status code.
 * @param   pVM     The cross context VM structure.
 * @param   pVCpu   The cross context virtual CPU structure of the calling EMT.
 */
VMMR3_INT_DECL(int) PGMR3PoolGrow(PVM pVM, PVMCPU pVCpu)
{
    /* This used to do a lot of stuff, but it has moved to ring-0 (PGMR0PoolGrow). */
    AssertReturn(pVM->pgm.s.pPoolR3->cCurPages < pVM->pgm.s.pPoolR3->cMaxPages, VERR_PGM_POOL_MAXED_OUT_ALREADY);
    int rc = VMMR3CallR0Emt(pVM, pVCpu, VMMR0_DO_PGM_POOL_GROW, 0, NULL);
    if (rc == VINF_SUCCESS)
        return rc;
    LogRel(("PGMR3PoolGrow: rc=%Rrc cCurPages=%#x cMaxPages=%#x\n",
            rc, pVM->pgm.s.pPoolR3->cCurPages, pVM->pgm.s.pPoolR3->cMaxPages));
    if (pVM->pgm.s.pPoolR3->cCurPages > 128 && RT_FAILURE_NP(rc))
        return -rc;
    return rc;
}


/**
 * Rendezvous callback used by pgmR3PoolClearAll that clears all shadow pages
 * and all modification counters.
 *
 * This is only called on one of the EMTs while the other ones are waiting for
 * it to complete this function.
 *
 * @returns VINF_SUCCESS (VBox strict status code).
 * @param   pVM     The cross context VM structure.
 * @param   pVCpu   The cross context virtual CPU structure of the calling EMT. Unused.
 * @param   fpvFlushRemTlb  When not NULL, we'll flush the REM TLB as well.
 *                          (This is the pvUser, so it has to be void *.)
 *
 */
DECLCALLBACK(VBOXSTRICTRC) pgmR3PoolClearAllRendezvous(PVM pVM, PVMCPU pVCpu, void *fpvFlushRemTlb)
{
    PPGMPOOL pPool = pVM->pgm.s.CTX_SUFF(pPool);
    STAM_PROFILE_START(&pPool->StatClearAll, c);
    NOREF(pVCpu);

    PGM_LOCK_VOID(pVM);
    Log(("pgmR3PoolClearAllRendezvous: cUsedPages=%d fpvFlushRemTlb=%RTbool\n", pPool->cUsedPages, !!fpvFlushRemTlb));

    /*
     * Iterate all the pages until we've encountered all that are in use.
     * This is a simple but not quite optimal solution.
     */
    unsigned cModifiedPages = 0; NOREF(cModifiedPages);
    unsigned cLeft = pPool->cUsedPages;
    uint32_t iPage = pPool->cCurPages;
    while (--iPage >= PGMPOOL_IDX_FIRST)
    {
        PPGMPOOLPAGE pPage = &pPool->aPages[iPage];
        if (pPage->GCPhys != NIL_RTGCPHYS)
        {
            switch (pPage->enmKind)
            {
                /*
                 * We only care about shadow page tables that reference physical memory
                 */
#ifdef PGM_WITH_LARGE_PAGES
                case PGMPOOLKIND_PAE_PD_PHYS:   /* Large pages reference 2 MB of physical memory, so we must clear them. */
                    if (pPage->cPresent)
                    {
                        PX86PDPAE pShwPD = (PX86PDPAE)PGMPOOL_PAGE_2_PTR_V2(pPool->CTX_SUFF(pVM), pVCpu, pPage);
                        for (unsigned i = 0; i < RT_ELEMENTS(pShwPD->a); i++)
                        {
                            //Assert((pShwPD->a[i].u & UINT64_C(0xfff0000000000f80)) == 0); - bogus, includes X86_PDE_PS.
                            if ((pShwPD->a[i].u & (X86_PDE_P | X86_PDE_PS)) == (X86_PDE_P | X86_PDE_PS))
                            {
                                pShwPD->a[i].u = 0;
                                Assert(pPage->cPresent);
                                pPage->cPresent--;
                            }
                        }
                        if (pPage->cPresent == 0)
                            pPage->iFirstPresent = NIL_PGMPOOL_PRESENT_INDEX;
                    }
                    goto default_case;

                case PGMPOOLKIND_EPT_PD_FOR_PHYS: /* Large pages reference 2 MB of physical memory, so we must clear them. */
                    if (pPage->cPresent)
                    {
                        PEPTPD pShwPD = (PEPTPD)PGMPOOL_PAGE_2_PTR_V2(pPool->CTX_SUFF(pVM), pVCpu, pPage);
                        for (unsigned i = 0; i < RT_ELEMENTS(pShwPD->a); i++)
                        {
                            if ((pShwPD->a[i].u & (EPT_E_READ | EPT_E_LEAF)) == (EPT_E_READ | EPT_E_LEAF))
                            {
                                pShwPD->a[i].u = 0;
                                Assert(pPage->cPresent);
                                pPage->cPresent--;
                            }
                        }
                        if (pPage->cPresent == 0)
                            pPage->iFirstPresent = NIL_PGMPOOL_PRESENT_INDEX;
                    }
                    goto default_case;

# ifdef VBOX_WITH_NESTED_HWVIRT_VMX_EPT
                case PGMPOOLKIND_EPT_PD_FOR_EPT_PD: /* Large pages reference 2 MB of physical memory, so we must clear them. */
                    if (pPage->cPresent)
                    {
                        PEPTPD pShwPD = (PEPTPD)PGMPOOL_PAGE_2_PTR_V2(pPool->CTX_SUFF(pVM), pVCpu, pPage);
                        for (unsigned i = 0; i < RT_ELEMENTS(pShwPD->a); i++)
                        {
                            if (   (pShwPD->a[i].u & EPT_PRESENT_MASK)
                                && (pShwPD->a[i].u & EPT_E_LEAF))
                            {
                                pShwPD->a[i].u = 0;
                                Assert(pPage->cPresent);
                                pPage->cPresent--;
                            }
                        }
                        if (pPage->cPresent == 0)
                            pPage->iFirstPresent = NIL_PGMPOOL_PRESENT_INDEX;
                    }
                    goto default_case;
# endif /* VBOX_WITH_NESTED_HWVIRT_VMX_EPT */
#endif /* PGM_WITH_LARGE_PAGES */

                case PGMPOOLKIND_32BIT_PT_FOR_32BIT_PT:
                case PGMPOOLKIND_32BIT_PT_FOR_32BIT_4MB:
                case PGMPOOLKIND_PAE_PT_FOR_32BIT_PT:
                case PGMPOOLKIND_PAE_PT_FOR_32BIT_4MB:
                case PGMPOOLKIND_PAE_PT_FOR_PAE_PT:
                case PGMPOOLKIND_PAE_PT_FOR_PAE_2MB:
                case PGMPOOLKIND_32BIT_PT_FOR_PHYS:
                case PGMPOOLKIND_PAE_PT_FOR_PHYS:
                case PGMPOOLKIND_EPT_PT_FOR_PHYS:
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX_EPT
                case PGMPOOLKIND_EPT_PT_FOR_EPT_PT:
                case PGMPOOLKIND_EPT_PT_FOR_EPT_2MB:
                case PGMPOOLKIND_EPT_PDPT_FOR_EPT_PDPT:
                case PGMPOOLKIND_EPT_PML4_FOR_EPT_PML4:
#endif
                {
                    if (pPage->cPresent)
                    {
                        void *pvShw = PGMPOOL_PAGE_2_PTR_V2(pPool->CTX_SUFF(pVM), pVCpu, pPage);
                        STAM_PROFILE_START(&pPool->StatZeroPage, z);
#if 0
                        /* Useful check for leaking references; *very* expensive though. */
                        switch (pPage->enmKind)
                        {
                            case PGMPOOLKIND_PAE_PT_FOR_32BIT_PT:
                            case PGMPOOLKIND_PAE_PT_FOR_32BIT_4MB:
                            case PGMPOOLKIND_PAE_PT_FOR_PAE_PT:
                            case PGMPOOLKIND_PAE_PT_FOR_PAE_2MB:
                            case PGMPOOLKIND_PAE_PT_FOR_PHYS:
                            {
                                bool fFoundFirst = false;
                                PPGMSHWPTPAE pPT = (PPGMSHWPTPAE)pvShw;
                                for (unsigned ptIndex = 0; ptIndex < RT_ELEMENTS(pPT->a); ptIndex++)
                                {
                                    if (pPT->a[ptIndex].u)
                                    {
                                        if (!fFoundFirst)
                                        {
                                            AssertFatalMsg(pPage->iFirstPresent <= ptIndex, ("ptIndex = %d first present = %d\n", ptIndex, pPage->iFirstPresent));
                                            if (pPage->iFirstPresent != ptIndex)
                                                Log(("ptIndex = %d first present = %d\n", ptIndex, pPage->iFirstPresent));
                                            fFoundFirst = true;
                                        }
                                        if (PGMSHWPTEPAE_IS_P(pPT->a[ptIndex]))
                                        {
                                            pgmPoolTracDerefGCPhysHint(pPool, pPage, PGMSHWPTEPAE_GET_HCPHYS(pPT->a[ptIndex]), NIL_RTGCPHYS);
                                            if (pPage->iFirstPresent == ptIndex)
                                                pPage->iFirstPresent = NIL_PGMPOOL_PRESENT_INDEX;
                                        }
                                    }
                                }
                                AssertFatalMsg(pPage->cPresent == 0, ("cPresent = %d pPage = %RGv\n", pPage->cPresent, pPage->GCPhys));
                                break;
                            }
                            default:
                                break;
                        }
#endif
                        ASMMemZeroPage(pvShw);
                        STAM_PROFILE_STOP(&pPool->StatZeroPage, z);
                        pPage->cPresent = 0;
                        pPage->iFirstPresent = NIL_PGMPOOL_PRESENT_INDEX;
                    }
                }
                RT_FALL_THRU();
                default:
#ifdef PGM_WITH_LARGE_PAGES
                default_case:
#endif
                    Assert(!pPage->cModifications || ++cModifiedPages);
                    Assert(pPage->iModifiedNext == NIL_PGMPOOL_IDX || pPage->cModifications);
                    Assert(pPage->iModifiedPrev == NIL_PGMPOOL_IDX || pPage->cModifications);
                    pPage->iModifiedNext = NIL_PGMPOOL_IDX;
                    pPage->iModifiedPrev = NIL_PGMPOOL_IDX;
                    pPage->cModifications = 0;
                    break;

            }
            if (!--cLeft)
                break;
        }
    }

#ifndef DEBUG_michael
    AssertMsg(cModifiedPages == pPool->cModifiedPages, ("%d != %d\n", cModifiedPages, pPool->cModifiedPages));
#endif
    pPool->iModifiedHead = NIL_PGMPOOL_IDX;
    pPool->cModifiedPages = 0;

    /*
     * Clear all the GCPhys links and rebuild the phys ext free list.
     */
    for (PPGMRAMRANGE pRam = pPool->CTX_SUFF(pVM)->pgm.s.CTX_SUFF(pRamRangesX);
         pRam;
         pRam = pRam->CTX_SUFF(pNext))
    {
        iPage = pRam->cb >> GUEST_PAGE_SHIFT;
        while (iPage-- > 0)
            PGM_PAGE_SET_TRACKING(pVM, &pRam->aPages[iPage], 0);
    }

    pPool->iPhysExtFreeHead = 0;
    PPGMPOOLPHYSEXT paPhysExts = pPool->CTX_SUFF(paPhysExts);
    const unsigned cMaxPhysExts = pPool->cMaxPhysExts;
    for (unsigned i = 0; i < cMaxPhysExts; i++)
    {
        paPhysExts[i].iNext = i + 1;
        paPhysExts[i].aidx[0] = NIL_PGMPOOL_IDX;
        paPhysExts[i].apte[0] = NIL_PGMPOOL_PHYSEXT_IDX_PTE;
        paPhysExts[i].aidx[1] = NIL_PGMPOOL_IDX;
        paPhysExts[i].apte[1] = NIL_PGMPOOL_PHYSEXT_IDX_PTE;
        paPhysExts[i].aidx[2] = NIL_PGMPOOL_IDX;
        paPhysExts[i].apte[2] = NIL_PGMPOOL_PHYSEXT_IDX_PTE;
    }
    paPhysExts[cMaxPhysExts - 1].iNext = NIL_PGMPOOL_PHYSEXT_INDEX;


#ifdef PGMPOOL_WITH_OPTIMIZED_DIRTY_PT
    /* Reset all dirty pages to reactivate the page monitoring. */
    /* Note: we must do this *after* clearing all page references and shadow page tables as there might be stale references to
     *       recently removed MMIO ranges around that might otherwise end up asserting in pgmPoolTracDerefGCPhysHint
     */
    for (unsigned i = 0; i < RT_ELEMENTS(pPool->aDirtyPages); i++)
    {
        unsigned idxPage = pPool->aidxDirtyPages[i];
        if (idxPage == NIL_PGMPOOL_IDX)
            continue;

        PPGMPOOLPAGE pPage = &pPool->aPages[idxPage];
        Assert(pPage->idx == idxPage);
        Assert(pPage->iMonitoredNext == NIL_PGMPOOL_IDX && pPage->iMonitoredPrev == NIL_PGMPOOL_IDX);

        AssertMsg(pPage->fDirty, ("Page %RGp (slot=%d) not marked dirty!", pPage->GCPhys, i));

        Log(("Reactivate dirty page %RGp\n", pPage->GCPhys));

        /* First write protect the page again to catch all write accesses. (before checking for changes -> SMP) */
        int rc = PGMHandlerPhysicalReset(pVM, pPage->GCPhys & ~(RTGCPHYS)GUEST_PAGE_OFFSET_MASK);
        AssertRCSuccess(rc);
        pPage->fDirty = false;

        pPool->aidxDirtyPages[i] = NIL_PGMPOOL_IDX;
    }

    /* Clear all dirty pages. */
    pPool->idxFreeDirtyPage = 0;
    pPool->cDirtyPages      = 0;
#endif

    /* Clear the PGM_SYNC_CLEAR_PGM_POOL flag on all VCPUs to prevent redundant flushes. */
    for (VMCPUID idCpu = 0; idCpu < pVM->cCpus; idCpu++)
        pVM->apCpusR3[idCpu]->pgm.s.fSyncFlags &= ~PGM_SYNC_CLEAR_PGM_POOL;

    /* Flush job finished. */
    VM_FF_CLEAR(pVM, VM_FF_PGM_POOL_FLUSH_PENDING);
    pPool->cPresent = 0;
    PGM_UNLOCK(pVM);

    PGM_INVL_ALL_VCPU_TLBS(pVM);

    if (fpvFlushRemTlb)
        for (VMCPUID idCpu = 0; idCpu < pVM->cCpus; idCpu++)
            CPUMSetChangedFlags(pVM->apCpusR3[idCpu], CPUM_CHANGED_GLOBAL_TLB_FLUSH);

    STAM_PROFILE_STOP(&pPool->StatClearAll, c);
    return VINF_SUCCESS;
}


/**
 * Clears the shadow page pool.
 *
 * @param   pVM             The cross context VM structure.
 * @param   fFlushRemTlb    When set, the REM TLB is scheduled for flushing as
 *                          well.
 */
void pgmR3PoolClearAll(PVM pVM, bool fFlushRemTlb)
{
    int rc = VMMR3EmtRendezvous(pVM, VMMEMTRENDEZVOUS_FLAGS_TYPE_ONCE, pgmR3PoolClearAllRendezvous, &fFlushRemTlb);
    AssertRC(rc);
}


/**
 * Stringifies a PGMPOOLACCESS value.
 */
static const char *pgmPoolPoolAccessToStr(uint8_t enmAccess)
{
    switch ((PGMPOOLACCESS)enmAccess)
    {
        case PGMPOOLACCESS_DONTCARE:         return "DONTCARE";
        case PGMPOOLACCESS_USER_RW:          return "USER_RW";
        case PGMPOOLACCESS_USER_R:           return "USER_R";
        case PGMPOOLACCESS_USER_RW_NX:       return "USER_RW_NX";
        case PGMPOOLACCESS_USER_R_NX:        return "USER_R_NX";
        case PGMPOOLACCESS_SUPERVISOR_RW:    return "SUPERVISOR_RW";
        case PGMPOOLACCESS_SUPERVISOR_R:     return "SUPERVISOR_R";
        case PGMPOOLACCESS_SUPERVISOR_RW_NX: return "SUPERVISOR_RW_NX";
        case PGMPOOLACCESS_SUPERVISOR_R_NX:  return "SUPERVISOR_R_NX";
    }
    return "Unknown Access";
}


/**
 * Stringifies a PGMPOOLKIND value.
 */
static const char *pgmPoolPoolKindToStr(uint8_t enmKind)
{
    switch ((PGMPOOLKIND)enmKind)
    {
        case PGMPOOLKIND_INVALID:
            return "INVALID";
        case PGMPOOLKIND_FREE:
            return "FREE";
        case PGMPOOLKIND_32BIT_PT_FOR_PHYS:
            return "32BIT_PT_FOR_PHYS";
        case PGMPOOLKIND_32BIT_PT_FOR_32BIT_PT:
            return "32BIT_PT_FOR_32BIT_PT";
        case PGMPOOLKIND_32BIT_PT_FOR_32BIT_4MB:
            return "32BIT_PT_FOR_32BIT_4MB";
        case PGMPOOLKIND_PAE_PT_FOR_PHYS:
            return "PAE_PT_FOR_PHYS";
        case PGMPOOLKIND_PAE_PT_FOR_32BIT_PT:
            return "PAE_PT_FOR_32BIT_PT";
        case PGMPOOLKIND_PAE_PT_FOR_32BIT_4MB:
            return "PAE_PT_FOR_32BIT_4MB";
        case PGMPOOLKIND_PAE_PT_FOR_PAE_PT:
            return "PAE_PT_FOR_PAE_PT";
        case PGMPOOLKIND_PAE_PT_FOR_PAE_2MB:
            return "PAE_PT_FOR_PAE_2MB";
        case PGMPOOLKIND_32BIT_PD:
            return "32BIT_PD";
        case PGMPOOLKIND_32BIT_PD_PHYS:
            return "32BIT_PD_PHYS";
        case PGMPOOLKIND_PAE_PD0_FOR_32BIT_PD:
            return "PAE_PD0_FOR_32BIT_PD";
        case PGMPOOLKIND_PAE_PD1_FOR_32BIT_PD:
            return "PAE_PD1_FOR_32BIT_PD";
        case PGMPOOLKIND_PAE_PD2_FOR_32BIT_PD:
            return "PAE_PD2_FOR_32BIT_PD";
        case PGMPOOLKIND_PAE_PD3_FOR_32BIT_PD:
            return "PAE_PD3_FOR_32BIT_PD";
        case PGMPOOLKIND_PAE_PD_FOR_PAE_PD:
            return "PAE_PD_FOR_PAE_PD";
        case PGMPOOLKIND_PAE_PD_PHYS:
            return "PAE_PD_PHYS";
        case PGMPOOLKIND_PAE_PDPT_FOR_32BIT:
            return "PAE_PDPT_FOR_32BIT";
        case PGMPOOLKIND_PAE_PDPT:
            return "PAE_PDPT";
        case PGMPOOLKIND_PAE_PDPT_PHYS:
            return "PAE_PDPT_PHYS";
        case PGMPOOLKIND_64BIT_PDPT_FOR_64BIT_PDPT:
            return "64BIT_PDPT_FOR_64BIT_PDPT";
        case PGMPOOLKIND_64BIT_PDPT_FOR_PHYS:
            return "64BIT_PDPT_FOR_PHYS";
        case PGMPOOLKIND_64BIT_PD_FOR_64BIT_PD:
            return "64BIT_PD_FOR_64BIT_PD";
        case PGMPOOLKIND_64BIT_PD_FOR_PHYS:
            return "64BIT_PD_FOR_PHYS";
        case PGMPOOLKIND_64BIT_PML4:
            return "64BIT_PML4";
        case PGMPOOLKIND_EPT_PDPT_FOR_PHYS:
            return "EPT_PDPT_FOR_PHYS";
        case PGMPOOLKIND_EPT_PD_FOR_PHYS:
            return "EPT_PD_FOR_PHYS";
        case PGMPOOLKIND_EPT_PT_FOR_PHYS:
            return "EPT_PT_FOR_PHYS";
        case PGMPOOLKIND_ROOT_NESTED:
            return "ROOT_NESTED";
        case PGMPOOLKIND_EPT_PT_FOR_EPT_PT:
            return "EPT_PT_FOR_EPT_PT";
        case PGMPOOLKIND_EPT_PT_FOR_EPT_2MB:
            return "EPT_PT_FOR_EPT_2MB";
        case PGMPOOLKIND_EPT_PD_FOR_EPT_PD:
            return "EPT_PD_FOR_EPT_PD";
        case PGMPOOLKIND_EPT_PDPT_FOR_EPT_PDPT:
            return "EPT_PDPT_FOR_EPT_PDPT";
        case PGMPOOLKIND_EPT_PML4_FOR_EPT_PML4:
            return "EPT_PML4_FOR_EPT_PML4";
    }
    return "Unknown kind!";
}


/**
 * Protect all pgm pool page table entries to monitor writes
 *
 * @param   pVM         The cross context VM structure.
 *
 * @remarks ASSUMES the caller will flush all TLBs!!
 */
void pgmR3PoolWriteProtectPages(PVM pVM)
{
    PGM_LOCK_ASSERT_OWNER(pVM);
    PPGMPOOL pPool = pVM->pgm.s.CTX_SUFF(pPool);
    unsigned cLeft = pPool->cUsedPages;
    unsigned iPage = pPool->cCurPages;
    while (--iPage >= PGMPOOL_IDX_FIRST)
    {
        PPGMPOOLPAGE pPage = &pPool->aPages[iPage];
        if (    pPage->GCPhys != NIL_RTGCPHYS
            &&  pPage->cPresent)
        {
            union
            {
                void           *pv;
                PX86PT          pPT;
                PPGMSHWPTPAE    pPTPae;
                PEPTPT          pPTEpt;
            } uShw;
            uShw.pv = PGMPOOL_PAGE_2_PTR(pVM, pPage);

            switch (pPage->enmKind)
            {
                /*
                 * We only care about shadow page tables.
                 */
                case PGMPOOLKIND_32BIT_PT_FOR_32BIT_PT:
                case PGMPOOLKIND_32BIT_PT_FOR_32BIT_4MB:
                case PGMPOOLKIND_32BIT_PT_FOR_PHYS:
                    for (unsigned iShw = 0; iShw < RT_ELEMENTS(uShw.pPT->a); iShw++)
                        if (uShw.pPT->a[iShw].u & X86_PTE_P)
                            uShw.pPT->a[iShw].u = ~(X86PGUINT)X86_PTE_RW;
                    break;

                case PGMPOOLKIND_PAE_PT_FOR_32BIT_PT:
                case PGMPOOLKIND_PAE_PT_FOR_32BIT_4MB:
                case PGMPOOLKIND_PAE_PT_FOR_PAE_PT:
                case PGMPOOLKIND_PAE_PT_FOR_PAE_2MB:
                case PGMPOOLKIND_PAE_PT_FOR_PHYS:
                    for (unsigned iShw = 0; iShw < RT_ELEMENTS(uShw.pPTPae->a); iShw++)
                        if (PGMSHWPTEPAE_IS_P(uShw.pPTPae->a[iShw]))
                            PGMSHWPTEPAE_SET_RO(uShw.pPTPae->a[iShw]);
                    break;

                case PGMPOOLKIND_EPT_PT_FOR_PHYS:
                    for (unsigned iShw = 0; iShw < RT_ELEMENTS(uShw.pPTEpt->a); iShw++)
                        if (uShw.pPTEpt->a[iShw].u & EPT_E_READ)
                            uShw.pPTEpt->a[iShw].u &= ~(X86PGPAEUINT)EPT_E_WRITE;
                    break;

                default:
                    break;
            }
            if (!--cLeft)
                break;
        }
    }
}


/**
 * @callback_method_impl{FNDBGFHANDLERINT, pgmpoolpages}
 */
static DECLCALLBACK(void) pgmR3PoolInfoPages(PVM pVM, PCDBGFINFOHLP pHlp, const char *pszArgs)
{
    RT_NOREF(pszArgs);

    PPGMPOOL const pPool  = pVM->pgm.s.CTX_SUFF(pPool);
    unsigned const cPages = pPool->cCurPages;
    unsigned       cLeft  = pPool->cUsedPages;
    for (unsigned iPage = 0; iPage < cPages; iPage++)
    {
        PGMPOOLPAGE volatile const *pPage = (PGMPOOLPAGE volatile const *)&pPool->aPages[iPage];
        RTGCPHYS const GCPhys = pPage->GCPhys;
        uint8_t const enmKind = pPage->enmKind;
        if (   enmKind != PGMPOOLKIND_INVALID
            && enmKind != PGMPOOLKIND_FREE)
        {
            pHlp->pfnPrintf(pHlp, "#%04x: HCPhys=%RHp GCPhys=%RGp %s %s %s%s%s\n",
                            iPage, pPage->Core.Key, GCPhys, pPage->fA20Enabled ? "A20 " : "!A20",
                            pgmPoolPoolKindToStr(enmKind),
                            pPage->enmAccess == PGMPOOLACCESS_DONTCARE ? "" : pgmPoolPoolAccessToStr(pPage->enmAccess),
                            pPage->fCached ? " cached" : "", pPage->fMonitored ? " monitored" : "");
            if (!--cLeft)
                break;
        }
    }
}


/**
 * @callback_method_impl{FNDBGFHANDLERINT, pgmpoolroots}
 */
static DECLCALLBACK(void) pgmR3PoolInfoRoots(PVM pVM, PCDBGFINFOHLP pHlp, const char *pszArgs)
{
    RT_NOREF(pszArgs);

    PPGMPOOL const pPool  = pVM->pgm.s.CTX_SUFF(pPool);
    unsigned const cPages = pPool->cCurPages;
    unsigned       cLeft  = pPool->cUsedPages;
    for (unsigned iPage = 0; iPage < cPages; iPage++)
    {
        PGMPOOLPAGE volatile const *pPage = (PGMPOOLPAGE volatile const *)&pPool->aPages[iPage];
        RTGCPHYS const GCPhys = pPage->GCPhys;
        if (GCPhys != NIL_RTGCPHYS)
        {
            uint8_t const enmKind = pPage->enmKind;
            switch (enmKind)
            {
                default:
                    break;

                case PGMPOOLKIND_PAE_PDPT_FOR_32BIT:
                case PGMPOOLKIND_PAE_PDPT:
                case PGMPOOLKIND_PAE_PDPT_PHYS:
                case PGMPOOLKIND_64BIT_PML4:
                case PGMPOOLKIND_ROOT_NESTED:
                case PGMPOOLKIND_EPT_PML4_FOR_EPT_PML4:
                    pHlp->pfnPrintf(pHlp, "#%04x: HCPhys=%RHp GCPhys=%RGp %s %s %s\n",
                                    iPage, pPage->Core.Key, GCPhys, pPage->fA20Enabled ? "A20 " : "!A20",
                                    pgmPoolPoolKindToStr(enmKind), pPage->fMonitored ? " monitored" : "");
                    break;
            }
            if (!--cLeft)
                break;
        }
    }
}

#ifdef VBOX_WITH_DEBUGGER

/**
 * Helper for pgmR3PoolCmdCheck that reports an error.
 */
static void pgmR3PoolCheckError(PPGMPOOLCHECKERSTATE pState, const char *pszFormat, ...)
{
    if (pState->fFirstMsg)
    {
        DBGCCmdHlpPrintf(pState->pCmdHlp, "Checking pool page #%i for %RGp %s\n",
                         pState->pPage->idx, pState->pPage->GCPhys, pgmPoolPoolKindToStr(pState->pPage->enmKind));
        pState->fFirstMsg = false;
    }

    va_list va;
    va_start(va, pszFormat);
    pState->pCmdHlp->pfnPrintfV(pState->pCmdHlp, NULL, pszFormat, va);
    va_end(va);
}


/**
 * @callback_method_impl{FNDBGCCMD, The '.pgmpoolcheck' command.}
 */
static DECLCALLBACK(int) pgmR3PoolCmdCheck(PCDBGCCMD pCmd, PDBGCCMDHLP pCmdHlp, PUVM pUVM, PCDBGCVAR paArgs, unsigned cArgs)
{
    DBGC_CMDHLP_REQ_UVM_RET(pCmdHlp, pCmd, pUVM);
    PVM pVM = pUVM->pVM;
    VM_ASSERT_VALID_EXT_RETURN(pVM, VERR_INVALID_VM_HANDLE);
    DBGC_CMDHLP_ASSERT_PARSER_RET(pCmdHlp, pCmd, -1, cArgs == 0);
    NOREF(paArgs);

    PGM_LOCK_VOID(pVM);
    PPGMPOOL            pPool = pVM->pgm.s.CTX_SUFF(pPool);
    PGMPOOLCHECKERSTATE State = { pCmdHlp, pVM, pPool, NULL, true, 0 };
    for (unsigned i = 0; i < pPool->cCurPages; i++)
    {
        PPGMPOOLPAGE pPage = &pPool->aPages[i];
        State.pPage     = pPage;
        State.fFirstMsg = true;

        if (pPage->idx != i)
            pgmR3PoolCheckError(&State, "Invalid idx value: %#x, expected %#x", pPage->idx, i);

        if (pPage->enmKind == PGMPOOLKIND_FREE)
            continue;
        if (pPage->enmKind > PGMPOOLKIND_LAST || pPage->enmKind <= PGMPOOLKIND_INVALID)
        {
            if (pPage->enmKind != PGMPOOLKIND_INVALID || pPage->idx != 0)
                pgmR3PoolCheckError(&State, "Invalid enmKind value: %#x\n", pPage->enmKind);
            continue;
        }

        void const     *pvGuestPage = NULL;
        PGMPAGEMAPLOCK  LockPage;
        if (   pPage->enmKind != PGMPOOLKIND_EPT_PDPT_FOR_PHYS
            && pPage->enmKind != PGMPOOLKIND_EPT_PD_FOR_PHYS
            && pPage->enmKind != PGMPOOLKIND_EPT_PT_FOR_PHYS
            && pPage->enmKind != PGMPOOLKIND_ROOT_NESTED)
        {
            int rc = PGMPhysGCPhys2CCPtrReadOnly(pVM, pPage->GCPhys, &pvGuestPage, &LockPage);
            if (RT_FAILURE(rc))
            {
                pgmR3PoolCheckError(&State, "PGMPhysGCPhys2CCPtrReadOnly failed for %RGp: %Rrc\n", pPage->GCPhys, rc);
                continue;
            }
        }
# define HCPHYS_TO_POOL_PAGE(a_HCPhys) (PPGMPOOLPAGE)RTAvloHCPhysGet(&pPool->HCPhysTree, (a_HCPhys))

        /*
         * Check if something obvious is out of sync.
         */
        switch (pPage->enmKind)
        {
            case PGMPOOLKIND_PAE_PT_FOR_PAE_PT:
            {
                PCPGMSHWPTPAE const pShwPT = (PCPGMSHWPTPAE)PGMPOOL_PAGE_2_PTR(pPool->CTX_SUFF(pVM), pPage);
                PCX86PDPAE const    pGstPT = (PCX86PDPAE)pvGuestPage;
                for (unsigned j = 0; j < RT_ELEMENTS(pShwPT->a); j++)
                    if (PGMSHWPTEPAE_IS_P(pShwPT->a[j]))
                    {
                        RTHCPHYS HCPhys = NIL_RTHCPHYS;
                        int rc = PGMPhysGCPhys2HCPhys(pPool->CTX_SUFF(pVM), pGstPT->a[j].u & X86_PTE_PAE_PG_MASK, &HCPhys);
                        if (   rc != VINF_SUCCESS
                            || PGMSHWPTEPAE_GET_HCPHYS(pShwPT->a[j]) != HCPhys)
                            pgmR3PoolCheckError(&State, "Mismatch HCPhys: rc=%Rrc idx=%#x guest %RX64 shw=%RX64 vs %RHp\n",
                                                rc, j, pGstPT->a[j].u, PGMSHWPTEPAE_GET_LOG(pShwPT->a[j]), HCPhys);
                        else if (   PGMSHWPTEPAE_IS_RW(pShwPT->a[j])
                                 && !(pGstPT->a[j].u & X86_PTE_RW))
                            pgmR3PoolCheckError(&State, "Mismatch r/w gst/shw: idx=%#x guest %RX64 shw=%RX64 vs %RHp\n",
                                                j, pGstPT->a[j].u, PGMSHWPTEPAE_GET_LOG(pShwPT->a[j]), HCPhys);
                    }
                break;
            }

            case PGMPOOLKIND_EPT_PT_FOR_EPT_PT:
            {
                PCEPTPT const pShwPT = (PCEPTPT)PGMPOOL_PAGE_2_PTR(pPool->CTX_SUFF(pVM), pPage);
                PCEPTPT const pGstPT = (PCEPTPT)pvGuestPage;
                for (unsigned j = 0; j < RT_ELEMENTS(pShwPT->a); j++)
                {
                    uint64_t const uShw = pShwPT->a[j].u;
                    if (uShw & EPT_PRESENT_MASK)
                    {
                        uint64_t const uGst   = pGstPT->a[j].u;
                        RTHCPHYS       HCPhys = NIL_RTHCPHYS;
                        int rc = PGMPhysGCPhys2HCPhys(pPool->CTX_SUFF(pVM), uGst & EPT_E_PG_MASK, &HCPhys);
                        if (   rc != VINF_SUCCESS
                            || (uShw & EPT_E_PG_MASK) != HCPhys)
                            pgmR3PoolCheckError(&State, "Mismatch HCPhys: rc=%Rrc idx=%#x guest %RX64 shw=%RX64 vs %RHp\n",
                                                rc, j, uGst, uShw, HCPhys);
                        if (      (uShw & (EPT_E_READ | EPT_E_WRITE | EPT_E_EXECUTE))
                               != (EPT_E_READ | EPT_E_WRITE | EPT_E_EXECUTE)
                            && (   ((uShw & EPT_E_READ)    && !(uGst & EPT_E_READ))
                                || ((uShw & EPT_E_WRITE)   && !(uGst & EPT_E_WRITE))
                                || ((uShw & EPT_E_EXECUTE) && !(uGst & EPT_E_EXECUTE)) ) )
                            pgmR3PoolCheckError(&State, "Mismatch r/w/x: idx=%#x guest %RX64 shw=%RX64\n", j, uGst, uShw);
                    }
                }
                break;
            }

            case PGMPOOLKIND_EPT_PT_FOR_EPT_2MB:
            {
                PCEPTPT const pShwPT = (PCEPTPT)PGMPOOL_PAGE_2_PTR(pPool->CTX_SUFF(pVM), pPage);
                for (unsigned j = 0; j < RT_ELEMENTS(pShwPT->a); j++)
                {
                    uint64_t const uShw = pShwPT->a[j].u;
                    if (uShw & EPT_E_LEAF)
                        pgmR3PoolCheckError(&State, "Leafness-error: idx=%#x shw=%RX64 (2MB)\n", j, uShw);
                    else if (uShw & EPT_PRESENT_MASK)
                    {
                        RTGCPHYS const GCPhysSubPage = pPage->GCPhys | (j << PAGE_SHIFT);
                        RTHCPHYS       HCPhys        = NIL_RTHCPHYS;
                        int rc = PGMPhysGCPhys2HCPhys(pPool->CTX_SUFF(pVM), GCPhysSubPage, &HCPhys);
                        if (   rc != VINF_SUCCESS
                            || (uShw & EPT_E_PG_MASK) != HCPhys)
                            pgmR3PoolCheckError(&State, "Mismatch HCPhys: rc=%Rrc idx=%#x guest %RX64 shw=%RX64 vs %RHp\n",
                                                rc, j, GCPhysSubPage, uShw, HCPhys);
                    }
                }
                break;
            }

            case PGMPOOLKIND_EPT_PD_FOR_EPT_PD:
            {
                PCEPTPD const pShwPD = (PCEPTPD)PGMPOOL_PAGE_2_PTR(pPool->CTX_SUFF(pVM), pPage);
                PCEPTPD const pGstPD = (PCEPTPD)pvGuestPage;
                for (unsigned j = 0; j < RT_ELEMENTS(pShwPD->a); j++)
                {
                    uint64_t const uShw = pShwPD->a[j].u;
                    if (uShw & EPT_PRESENT_MASK)
                    {
                        uint64_t const uGst = pGstPD->a[j].u;
                        if (uShw & EPT_E_LEAF)
                        {
                            if (!(uGst & EPT_E_LEAF))
                                pgmR3PoolCheckError(&State, "Leafness-mismatch: idx=%#x guest %RX64 shw=%RX64\n", j, uGst, uShw);
                            else
                            {
                                RTHCPHYS HCPhys = NIL_RTHCPHYS;
                                int rc = PGMPhysGCPhys2HCPhys(pPool->CTX_SUFF(pVM), uGst & EPT_PDE2M_PG_MASK, &HCPhys);
                                if (   rc != VINF_SUCCESS
                                    || (uShw & EPT_E_PG_MASK) != HCPhys)
                                    pgmR3PoolCheckError(&State, "Mismatch HCPhys: rc=%Rrc idx=%#x guest %RX64 shw=%RX64 vs %RHp (2MB)\n",
                                                        rc, j, uGst, uShw, HCPhys);
                            }
                        }
                        else
                        {
                            PPGMPOOLPAGE pSubPage = HCPHYS_TO_POOL_PAGE(uShw & EPT_E_PG_MASK);
                            if (pSubPage)
                            {
                                if (   pSubPage->enmKind != PGMPOOLKIND_EPT_PT_FOR_EPT_PT
                                    && pSubPage->enmKind != PGMPOOLKIND_EPT_PT_FOR_EPT_2MB)
                                    pgmR3PoolCheckError(&State, "Wrong sub-table type: idx=%#x guest %RX64 shw=%RX64: idxSub=%#x %s\n",
                                                        j, uGst, uShw, pSubPage->idx, pgmPoolPoolKindToStr(pSubPage->enmKind));
                                if (pSubPage->fA20Enabled != pPage->fA20Enabled)
                                    pgmR3PoolCheckError(&State, "Wrong sub-table A20: idx=%#x guest %RX64 shw=%RX64: idxSub=%#x A20=%d, expected %d\n",
                                                        j, uGst, uShw, pSubPage->idx, pSubPage->fA20Enabled, pPage->fA20Enabled);
                                if (pSubPage->GCPhys != (uGst & EPT_E_PG_MASK))
                                    pgmR3PoolCheckError(&State, "Wrong sub-table GCPhys: idx=%#x guest %RX64 shw=%RX64: GCPhys=%#RGp idxSub=%#x\n",
                                                        j, uGst, uShw, pSubPage->GCPhys, pSubPage->idx);
                            }
                            else
                                pgmR3PoolCheckError(&State, "sub table not found: idx=%#x shw=%RX64\n", j, uShw);
                        }
                        if (      (uShw & (EPT_E_READ | EPT_E_WRITE | EPT_E_EXECUTE))
                               != (EPT_E_READ | EPT_E_WRITE | EPT_E_EXECUTE)
                            && (   ((uShw & EPT_E_READ)    && !(uGst & EPT_E_READ))
                                || ((uShw & EPT_E_WRITE)   && !(uGst & EPT_E_WRITE))
                                || ((uShw & EPT_E_EXECUTE) && !(uGst & EPT_E_EXECUTE)) ) )
                            pgmR3PoolCheckError(&State, "Mismatch r/w/x: idx=%#x guest %RX64 shw=%RX64\n",
                                                j, uGst, uShw);
                    }
                }
                break;
            }

            case PGMPOOLKIND_EPT_PDPT_FOR_EPT_PDPT:
            {
                PCEPTPDPT const pShwPDPT = (PCEPTPDPT)PGMPOOL_PAGE_2_PTR(pPool->CTX_SUFF(pVM), pPage);
                PCEPTPDPT const pGstPDPT = (PCEPTPDPT)pvGuestPage;
                for (unsigned j = 0; j < RT_ELEMENTS(pShwPDPT->a); j++)
                {
                    uint64_t const uShw = pShwPDPT->a[j].u;
                    if (uShw & EPT_PRESENT_MASK)
                    {
                        uint64_t const uGst = pGstPDPT->a[j].u;
                        if (uShw & EPT_E_LEAF)
                            pgmR3PoolCheckError(&State, "No 1GiB shadow pages: idx=%#x guest %RX64 shw=%RX64\n", j, uGst, uShw);
                        else
                        {
                            PPGMPOOLPAGE pSubPage = HCPHYS_TO_POOL_PAGE(uShw & EPT_E_PG_MASK);
                            if (pSubPage)
                            {
                                if (pSubPage->enmKind != PGMPOOLKIND_EPT_PD_FOR_EPT_PD)
                                    pgmR3PoolCheckError(&State, "Wrong sub-table type: idx=%#x guest %RX64 shw=%RX64: idxSub=%#x %s\n",
                                                        j, uGst, uShw, pSubPage->idx, pgmPoolPoolKindToStr(pSubPage->enmKind));
                                if (pSubPage->fA20Enabled != pPage->fA20Enabled)
                                    pgmR3PoolCheckError(&State, "Wrong sub-table A20: idx=%#x guest %RX64 shw=%RX64: idxSub=%#x A20=%d, expected %d\n",
                                                        j, uGst, uShw, pSubPage->idx, pSubPage->fA20Enabled, pPage->fA20Enabled);
                                if (pSubPage->GCPhys != (uGst & EPT_E_PG_MASK))
                                    pgmR3PoolCheckError(&State, "Wrong sub-table GCPhys: idx=%#x guest %RX64 shw=%RX64: GCPhys=%#RGp idxSub=%#x\n",
                                                        j, uGst, uShw, pSubPage->GCPhys, pSubPage->idx);
                            }
                            else
                                pgmR3PoolCheckError(&State, "sub table not found: idx=%#x shw=%RX64\n", j, uShw);

                        }
                        if (      (uShw & (EPT_E_READ | EPT_E_WRITE | EPT_E_EXECUTE))
                               != (EPT_E_READ | EPT_E_WRITE | EPT_E_EXECUTE)
                            && (   ((uShw & EPT_E_READ)    && !(uGst & EPT_E_READ))
                                || ((uShw & EPT_E_WRITE)   && !(uGst & EPT_E_WRITE))
                                || ((uShw & EPT_E_EXECUTE) && !(uGst & EPT_E_EXECUTE)) ) )
                            pgmR3PoolCheckError(&State, "Mismatch r/w/x: idx=%#x guest %RX64 shw=%RX64\n",
                                                j, uGst, uShw);
                    }
                }
                break;
            }

            case PGMPOOLKIND_EPT_PML4_FOR_EPT_PML4:
            {
                PCEPTPML4 const pShwPML4 = (PCEPTPML4)PGMPOOL_PAGE_2_PTR(pPool->CTX_SUFF(pVM), pPage);
                PCEPTPML4 const pGstPML4 = (PCEPTPML4)pvGuestPage;
                for (unsigned j = 0; j < RT_ELEMENTS(pShwPML4->a); j++)
                {
                    uint64_t const uShw = pShwPML4->a[j].u;
                    if (uShw & EPT_PRESENT_MASK)
                    {
                        uint64_t const uGst = pGstPML4->a[j].u;
                        if (uShw & EPT_E_LEAF)
                            pgmR3PoolCheckError(&State, "No 0.5TiB shadow pages: idx=%#x guest %RX64 shw=%RX64\n", j, uGst, uShw);
                        else
                        {
                            PPGMPOOLPAGE pSubPage = HCPHYS_TO_POOL_PAGE(uShw & EPT_E_PG_MASK);
                            if (pSubPage)
                            {
                                if (pSubPage->enmKind != PGMPOOLKIND_EPT_PDPT_FOR_EPT_PDPT)
                                    pgmR3PoolCheckError(&State, "Wrong sub-table type: idx=%#x guest %RX64 shw=%RX64: idxSub=%#x %s\n",
                                                        j, uGst, uShw, pSubPage->idx, pgmPoolPoolKindToStr(pSubPage->enmKind));
                                if (pSubPage->fA20Enabled != pPage->fA20Enabled)
                                    pgmR3PoolCheckError(&State, "Wrong sub-table A20: idx=%#x guest %RX64 shw=%RX64: idxSub=%#x A20=%d, expected %d\n",
                                                        j, uGst, uShw, pSubPage->idx, pSubPage->fA20Enabled, pPage->fA20Enabled);
                                if (pSubPage->GCPhys != (uGst & EPT_E_PG_MASK))
                                    pgmR3PoolCheckError(&State, "Wrong sub-table GCPhys: idx=%#x guest %RX64 shw=%RX64: GCPhys=%#RGp idxSub=%#x\n",
                                                        j, uGst, uShw, pSubPage->GCPhys, pSubPage->idx);
                            }
                            else
                                pgmR3PoolCheckError(&State, "sub table not found: idx=%#x shw=%RX64\n", j, uShw);

                        }
                        if (      (uShw & (EPT_E_READ | EPT_E_WRITE | EPT_E_EXECUTE))
                               != (EPT_E_READ | EPT_E_WRITE | EPT_E_EXECUTE)
                            && (   ((uShw & EPT_E_READ)    && !(uGst & EPT_E_READ))
                                || ((uShw & EPT_E_WRITE)   && !(uGst & EPT_E_WRITE))
                                || ((uShw & EPT_E_EXECUTE) && !(uGst & EPT_E_EXECUTE)) ) )
                            pgmR3PoolCheckError(&State, "Mismatch r/w/x: idx=%#x guest %RX64 shw=%RX64\n",
                                                j, uGst, uShw);
                    }
                }
                break;
            }
        }

#undef HCPHYS_TO_POOL_PAGE
        if (pvGuestPage)
            PGMPhysReleasePageMappingLock(pVM, &LockPage);
    }
    PGM_UNLOCK(pVM);

    if (State.cErrors > 0)
        return DBGCCmdHlpFail(pCmdHlp, pCmd, "Found %#x errors", State.cErrors);
    DBGCCmdHlpPrintf(pCmdHlp, "no errors found\n");
    return VINF_SUCCESS;
}

#endif /* VBOX_WITH_DEBUGGER */