summaryrefslogtreecommitdiffstats
path: root/src/VBox/VMM/VMMR3/EMR3Nem.cpp
blob: cc977299bf5cc6793425974a398e8e209ef43938 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
/* $Id: EMR3Nem.cpp $ */
/** @file
 * EM - Execution Monitor / Manager - NEM interface.
 */

/*
 * 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
 */


/*********************************************************************************************************************************
*   Header Files                                                                                                                 *
*********************************************************************************************************************************/
#define LOG_GROUP LOG_GROUP_EM
#define VMCPU_INCL_CPUM_GST_CTX
#include <VBox/vmm/em.h>
#include <VBox/vmm/vmm.h>
#include <VBox/vmm/selm.h>
#include <VBox/vmm/trpm.h>
#include <VBox/vmm/iem.h>
#include <VBox/vmm/iom.h>
#include <VBox/vmm/nem.h>
#include <VBox/vmm/dbgf.h>
#include <VBox/vmm/pgm.h>
#include <VBox/vmm/tm.h>
#include <VBox/vmm/mm.h>
#include <VBox/vmm/ssm.h>
#include <VBox/vmm/pdmapi.h>
#include <VBox/vmm/pdmcritsect.h>
#include <VBox/vmm/pdmqueue.h>
#include "EMInternal.h"
#include <VBox/vmm/vm.h>
#include <VBox/vmm/gim.h>
#include <VBox/vmm/cpumdis.h>
#include <VBox/dis.h>
#include <VBox/disopcode.h>
#include <VBox/err.h>
#include <VBox/vmm/dbgf.h>
#include "VMMTracing.h"

#include <iprt/asm.h>


/*********************************************************************************************************************************
*   Internal Functions                                                                                                           *
*********************************************************************************************************************************/
static int      emR3NemHandleRC(PVM pVM, PVMCPU pVCpu, int rc);
DECLINLINE(int) emR3NemExecuteInstruction(PVM pVM, PVMCPU pVCpu, const char *pszPrefix, int rcGC = VINF_SUCCESS);
static int      emR3NemExecuteIOInstruction(PVM pVM, PVMCPU pVCpu);
static int      emR3NemForcedActions(PVM pVM, PVMCPU pVCpu);

#define EMHANDLERC_WITH_NEM
#define emR3ExecuteInstruction   emR3NemExecuteInstruction
#define emR3ExecuteIOInstruction emR3NemExecuteIOInstruction
#include "EMHandleRCTmpl.h"


/**
 * Executes instruction in NEM mode if we can.
 *
 * This is somewhat comparable to REMR3EmulateInstruction.
 *
 * @returns VBox strict status code.
 * @retval  VINF_EM_DBG_STEPPED on success.
 * @retval  VERR_EM_CANNOT_EXEC_GUEST if we cannot execute guest instructions in
 *          HM right now.
 *
 * @param   pVM     The cross context VM structure.
 * @param   pVCpu   The cross context virtual CPU structure for the calling EMT.
 * @param   fFlags  Combinations of EM_ONE_INS_FLAGS_XXX.
 * @thread  EMT.
 */
VBOXSTRICTRC emR3NemSingleInstruction(PVM pVM, PVMCPU pVCpu, uint32_t fFlags)
{
    Assert(!(fFlags & ~EM_ONE_INS_FLAGS_MASK));

    if (!NEMR3CanExecuteGuest(pVM, pVCpu))
        return VINF_EM_RESCHEDULE;

    uint64_t const uOldRip = pVCpu->cpum.GstCtx.rip;
    for (;;)
    {
        /*
         * Service necessary FFs before going into HM.
         */
        if (   VM_FF_IS_ANY_SET(pVM, VM_FF_HIGH_PRIORITY_PRE_RAW_MASK)
            || VMCPU_FF_IS_ANY_SET(pVCpu, VMCPU_FF_HIGH_PRIORITY_PRE_RAW_MASK))
        {
            VBOXSTRICTRC rcStrict = emR3NemForcedActions(pVM, pVCpu);
            if (rcStrict != VINF_SUCCESS)
            {
                Log(("emR3NemSingleInstruction: FFs before -> %Rrc\n", VBOXSTRICTRC_VAL(rcStrict)));
                return rcStrict;
            }
        }

        /*
         * Go execute it.
         */
        bool fOld = NEMR3SetSingleInstruction(pVM, pVCpu, true);
        VBOXSTRICTRC rcStrict = NEMR3RunGC(pVM, pVCpu);
        NEMR3SetSingleInstruction(pVM, pVCpu, fOld);
        LogFlow(("emR3NemSingleInstruction: %Rrc\n", VBOXSTRICTRC_VAL(rcStrict)));

        /*
         * Handle high priority FFs and informational status codes.  We don't do
         * normal FF processing the caller or the next call can deal with them.
         */
        VMCPU_FF_CLEAR_MASK(pVCpu, VMCPU_FF_RESUME_GUEST_MASK);
        if (   VM_FF_IS_ANY_SET(pVM, VM_FF_HIGH_PRIORITY_POST_MASK)
            || VMCPU_FF_IS_ANY_SET(pVCpu, VMCPU_FF_HIGH_PRIORITY_POST_MASK))
        {
            rcStrict = emR3HighPriorityPostForcedActions(pVM, pVCpu, rcStrict);
            LogFlow(("emR3NemSingleInstruction: FFs after -> %Rrc\n", VBOXSTRICTRC_VAL(rcStrict)));
        }

        if (rcStrict != VINF_SUCCESS && (rcStrict < VINF_EM_FIRST || rcStrict > VINF_EM_LAST))
        {
            rcStrict = emR3NemHandleRC(pVM, pVCpu, VBOXSTRICTRC_TODO(rcStrict));
            Log(("emR3NemSingleInstruction: emR3NemHandleRC -> %Rrc\n", VBOXSTRICTRC_VAL(rcStrict)));
        }

        /*
         * Done?
         */
        CPUM_ASSERT_NOT_EXTRN(pVCpu, CPUMCTX_EXTRN_RIP);
        if (   (rcStrict != VINF_SUCCESS && rcStrict != VINF_EM_DBG_STEPPED)
            || !(fFlags & EM_ONE_INS_FLAGS_RIP_CHANGE)
            || pVCpu->cpum.GstCtx.rip != uOldRip)
        {
            if (rcStrict == VINF_SUCCESS && pVCpu->cpum.GstCtx.rip != uOldRip)
                rcStrict = VINF_EM_DBG_STEPPED;
            Log(("emR3NemSingleInstruction: returns %Rrc (rip %llx -> %llx)\n",
                 VBOXSTRICTRC_VAL(rcStrict), uOldRip, pVCpu->cpum.GstCtx.rip));
            CPUM_IMPORT_EXTRN_RET(pVCpu, ~CPUMCTX_EXTRN_KEEPER_MASK);
            return rcStrict;
        }
    }
}


/**
 * Executes one (or perhaps a few more) instruction(s).
 *
 * @returns VBox status code suitable for EM.
 *
 * @param   pVM         The cross context VM structure.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   rcRC        Return code from RC.
 * @param   pszPrefix   Disassembly prefix. If not NULL we'll disassemble the
 *                      instruction and prefix the log output with this text.
 */
#if defined(LOG_ENABLED) || defined(DOXYGEN_RUNNING)
static int emR3NemExecuteInstructionWorker(PVM pVM, PVMCPU pVCpu, int rcRC, const char *pszPrefix)
#else
static int emR3NemExecuteInstructionWorker(PVM pVM, PVMCPU pVCpu, int rcRC)
#endif
{
    NOREF(rcRC);

#ifdef LOG_ENABLED
    /*
     * Log it.
     */
    Log(("EMINS: %04x:%RGv RSP=%RGv\n", pVCpu->cpum.GstCtx.cs.Sel, (RTGCPTR)pVCpu->cpum.GstCtx.rip, (RTGCPTR)pVCpu->cpum.GstCtx.rsp));
    if (pszPrefix)
    {
        DBGFR3_INFO_LOG(pVM, pVCpu, "cpumguest", pszPrefix);
        DBGFR3_DISAS_INSTR_CUR_LOG(pVCpu, pszPrefix);
    }
#endif

    /*
     * Use IEM and fallback on REM if the functionality is missing.
     * Once IEM gets mature enough, nothing should ever fall back.
     */
    STAM_PROFILE_START(&pVCpu->em.s.StatIEMEmu, a);

    VBOXSTRICTRC rcStrict;
    uint32_t     idxContinueExitRec = pVCpu->em.s.idxContinueExitRec;
    RT_UNTRUSTED_NONVOLATILE_COPY_FENCE();
    if (idxContinueExitRec >= RT_ELEMENTS(pVCpu->em.s.aExitRecords))
    {
        CPUM_IMPORT_EXTRN_RET(pVCpu, IEM_CPUMCTX_EXTRN_MUST_MASK);
        rcStrict = IEMExecOne(pVCpu);
    }
    else
    {
        RT_UNTRUSTED_VALIDATED_FENCE();
        rcStrict = EMHistoryExec(pVCpu, &pVCpu->em.s.aExitRecords[idxContinueExitRec], 0);
        LogFlow(("emR3NemExecuteInstruction: %Rrc (EMHistoryExec)\n", VBOXSTRICTRC_VAL(rcStrict)));
    }

    STAM_PROFILE_STOP(&pVCpu->em.s.StatIEMEmu, a);

    NOREF(pVM);
    return VBOXSTRICTRC_TODO(rcStrict);
}


/**
 * Executes one (or perhaps a few more) instruction(s).
 * This is just a wrapper for discarding pszPrefix in non-logging builds.
 *
 * @returns VBox status code suitable for EM.
 * @param   pVM         The cross context VM structure.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pszPrefix   Disassembly prefix. If not NULL we'll disassemble the
 *                      instruction and prefix the log output with this text.
 * @param   rcGC        GC return code
 */
DECLINLINE(int) emR3NemExecuteInstruction(PVM pVM, PVMCPU pVCpu, const char *pszPrefix, int rcGC)
{
#ifdef LOG_ENABLED
    return emR3NemExecuteInstructionWorker(pVM, pVCpu, rcGC, pszPrefix);
#else
    RT_NOREF_PV(pszPrefix);
    return emR3NemExecuteInstructionWorker(pVM, pVCpu, rcGC);
#endif
}

/**
 * Executes one (or perhaps a few more) IO instruction(s).
 *
 * @returns VBox status code suitable for EM.
 * @param   pVM         The cross context VM structure.
 * @param   pVCpu       The cross context virtual CPU structure.
 */
static int emR3NemExecuteIOInstruction(PVM pVM, PVMCPU pVCpu)
{
    RT_NOREF_PV(pVM);
    STAM_PROFILE_START(&pVCpu->em.s.StatIOEmu, a);

    /*
     * Hand it over to the interpreter.
     */
    CPUM_IMPORT_EXTRN_RET(pVCpu, IEM_CPUMCTX_EXTRN_MUST_MASK);
    VBOXSTRICTRC rcStrict;
    uint32_t     idxContinueExitRec = pVCpu->em.s.idxContinueExitRec;
    RT_UNTRUSTED_NONVOLATILE_COPY_FENCE();
    if (idxContinueExitRec >= RT_ELEMENTS(pVCpu->em.s.aExitRecords))
    {
        rcStrict = IEMExecOne(pVCpu);
        LogFlow(("emR3NemExecuteIOInstruction: %Rrc (IEMExecOne)\n", VBOXSTRICTRC_VAL(rcStrict)));
        STAM_COUNTER_INC(&pVCpu->em.s.StatIoIem);
    }
    else
    {
        RT_UNTRUSTED_VALIDATED_FENCE();
        rcStrict = EMHistoryExec(pVCpu, &pVCpu->em.s.aExitRecords[idxContinueExitRec], 0);
        LogFlow(("emR3NemExecuteIOInstruction: %Rrc (EMHistoryExec)\n", VBOXSTRICTRC_VAL(rcStrict)));
        STAM_COUNTER_INC(&pVCpu->em.s.StatIoRestarted);
    }

    STAM_PROFILE_STOP(&pVCpu->em.s.StatIOEmu, a);
    return VBOXSTRICTRC_TODO(rcStrict);
}


/**
 * Process NEM specific forced actions.
 *
 * This function is called when any FFs in VM_FF_HIGH_PRIORITY_PRE_RAW_MASK
 * or/and VMCPU_FF_HIGH_PRIORITY_PRE_RAW_MASK are pending.
 *
 * @returns VBox status code. May return VINF_EM_NO_MEMORY but none of the other
 *          EM statuses.
 * @param   pVM         The cross context VM structure.
 * @param   pVCpu       The cross context virtual CPU structure.
 */
static int emR3NemForcedActions(PVM pVM, PVMCPU pVCpu)
{
    /*
     * Sync page directory should not happen in NEM mode.
     */
    if (VMCPU_FF_IS_ANY_SET(pVCpu, VMCPU_FF_PGM_SYNC_CR3 | VMCPU_FF_PGM_SYNC_CR3_NON_GLOBAL))
    {
        Log(("NEM: TODO: Make VMCPU_FF_PGM_SYNC_CR3 / VMCPU_FF_PGM_SYNC_CR3_NON_GLOBAL quiet! (%#RX64)\n", (uint64_t)pVCpu->fLocalForcedActions));
        VMCPU_FF_CLEAR_MASK(pVCpu, VMCPU_FF_PGM_SYNC_CR3 | VMCPU_FF_PGM_SYNC_CR3_NON_GLOBAL);
    }

    /*
     * Allocate handy pages (just in case the above actions have consumed some pages).
     */
    if (VM_FF_IS_PENDING_EXCEPT(pVM, VM_FF_PGM_NEED_HANDY_PAGES, VM_FF_PGM_NO_MEMORY))
    {
        int rc = PGMR3PhysAllocateHandyPages(pVM);
        if (RT_FAILURE(rc))
            return rc;
    }

    /*
     * Check whether we're out of memory now.
     *
     * This may stem from some of the above actions or operations that has been executed
     * since we ran FFs. The allocate handy pages must for instance always be followed by
     * this check.
     */
    if (VM_FF_IS_SET(pVM, VM_FF_PGM_NO_MEMORY))
        return VINF_EM_NO_MEMORY;

    return VINF_SUCCESS;
}


/**
 * Executes hardware accelerated raw code. (Intel VT-x & AMD-V)
 *
 * This function contains the raw-mode version of the inner
 * execution loop (the outer loop being in EMR3ExecuteVM()).
 *
 * @returns VBox status code. The most important ones are: VINF_EM_RESCHEDULE, VINF_EM_RESCHEDULE_RAW,
 *          VINF_EM_RESCHEDULE_REM, VINF_EM_SUSPEND, VINF_EM_RESET and VINF_EM_TERMINATE.
 *
 * @param   pVM         The cross context VM structure.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pfFFDone    Where to store an indicator telling whether or not
 *                      FFs were done before returning.
 */
VBOXSTRICTRC emR3NemExecute(PVM pVM, PVMCPU pVCpu, bool *pfFFDone)
{
    VBOXSTRICTRC rcStrict = VERR_IPE_UNINITIALIZED_STATUS;

    LogFlow(("emR3NemExecute%d: (cs:eip=%04x:%RGv)\n", pVCpu->idCpu, pVCpu->cpum.GstCtx.cs.Sel, (RTGCPTR)pVCpu->cpum.GstCtx.rip));
    *pfFFDone = false;

    STAM_REL_COUNTER_INC(&pVCpu->em.s.StatNEMExecuteCalled);

    /*
     * Spin till we get a forced action which returns anything but VINF_SUCCESS.
     */
    for (;;)
    {
        STAM_PROFILE_ADV_START(&pVCpu->em.s.StatNEMEntry, a);

        /*
         * Check that we can execute in NEM mode.
         */
        if (NEMR3CanExecuteGuest(pVM, pVCpu))
        { /* likely */ }
        else
        {
            rcStrict = VINF_EM_RESCHEDULE_REM;
            break;
        }

        /*
         * Process high priority pre-execution raw-mode FFs.
         */
        if (   VM_FF_IS_ANY_SET(pVM, VM_FF_HIGH_PRIORITY_PRE_RAW_MASK)
            || VMCPU_FF_IS_ANY_SET(pVCpu, VMCPU_FF_HIGH_PRIORITY_PRE_RAW_MASK))
        {
            rcStrict = emR3NemForcedActions(pVM, pVCpu);
            if (rcStrict != VINF_SUCCESS)
                break;
        }

#ifdef LOG_ENABLED
        /*
         * Log important stuff before entering GC.
         */
        if (TRPMHasTrap(pVCpu))
            Log(("CPU%d: Pending hardware interrupt=0x%x cs:rip=%04X:%RGv\n", pVCpu->idCpu, TRPMGetTrapNo(pVCpu), pVCpu->cpum.GstCtx.cs.Sel, (RTGCPTR)pVCpu->cpum.GstCtx.rip));

        if (!(pVCpu->cpum.GstCtx.fExtrn & (  CPUMCTX_EXTRN_RIP | CPUMCTX_EXTRN_CS  | CPUMCTX_EXTRN_RFLAGS | CPUMCTX_EXTRN_SS
                                           | CPUMCTX_EXTRN_RSP | CPUMCTX_EXTRN_CR0 | CPUMCTX_EXTRN_CR4    | CPUMCTX_EXTRN_EFER)))
        {
            uint32_t cpl = CPUMGetGuestCPL(pVCpu);
            if (pVM->cCpus == 1)
            {
                if (pVCpu->cpum.GstCtx.eflags.Bits.u1VM)
                    Log(("NEMV86: %08x IF=%d\n", pVCpu->cpum.GstCtx.eip, pVCpu->cpum.GstCtx.eflags.Bits.u1IF));
                else if (CPUMIsGuestIn64BitCodeEx(&pVCpu->cpum.GstCtx))
                    Log(("NEMR%d: %04x:%RGv ESP=%RGv IF=%d IOPL=%d CR0=%x CR4=%x EFER=%x\n", cpl, pVCpu->cpum.GstCtx.cs.Sel, (RTGCPTR)pVCpu->cpum.GstCtx.rip, pVCpu->cpum.GstCtx.rsp, pVCpu->cpum.GstCtx.eflags.Bits.u1IF, pVCpu->cpum.GstCtx.eflags.Bits.u2IOPL, (uint32_t)pVCpu->cpum.GstCtx.cr0, (uint32_t)pVCpu->cpum.GstCtx.cr4, (uint32_t)pVCpu->cpum.GstCtx.msrEFER));
                else
                    Log(("NEMR%d: %04x:%08x ESP=%08X IF=%d IOPL=%d CR0=%x CR4=%x EFER=%x\n", cpl, pVCpu->cpum.GstCtx.cs.Sel,          pVCpu->cpum.GstCtx.eip, pVCpu->cpum.GstCtx.esp, pVCpu->cpum.GstCtx.eflags.Bits.u1IF, pVCpu->cpum.GstCtx.eflags.Bits.u2IOPL, (uint32_t)pVCpu->cpum.GstCtx.cr0, (uint32_t)pVCpu->cpum.GstCtx.cr4, (uint32_t)pVCpu->cpum.GstCtx.msrEFER));
            }
            else
            {
                if (pVCpu->cpum.GstCtx.eflags.Bits.u1VM)
                    Log(("NEMV86-CPU%d: %08x IF=%d\n", pVCpu->idCpu, pVCpu->cpum.GstCtx.eip, pVCpu->cpum.GstCtx.eflags.Bits.u1IF));
                else if (CPUMIsGuestIn64BitCodeEx(&pVCpu->cpum.GstCtx))
                    Log(("NEMR%d-CPU%d: %04x:%RGv ESP=%RGv IF=%d IOPL=%d CR0=%x CR4=%x EFER=%x\n", cpl, pVCpu->idCpu, pVCpu->cpum.GstCtx.cs.Sel, (RTGCPTR)pVCpu->cpum.GstCtx.rip, pVCpu->cpum.GstCtx.rsp, pVCpu->cpum.GstCtx.eflags.Bits.u1IF, pVCpu->cpum.GstCtx.eflags.Bits.u2IOPL, (uint32_t)pVCpu->cpum.GstCtx.cr0, (uint32_t)pVCpu->cpum.GstCtx.cr4, (uint32_t)pVCpu->cpum.GstCtx.msrEFER));
                else
                    Log(("NEMR%d-CPU%d: %04x:%08x ESP=%08X IF=%d IOPL=%d CR0=%x CR4=%x EFER=%x\n", cpl, pVCpu->idCpu, pVCpu->cpum.GstCtx.cs.Sel,          pVCpu->cpum.GstCtx.eip, pVCpu->cpum.GstCtx.esp, pVCpu->cpum.GstCtx.eflags.Bits.u1IF, pVCpu->cpum.GstCtx.eflags.Bits.u2IOPL, (uint32_t)pVCpu->cpum.GstCtx.cr0, (uint32_t)pVCpu->cpum.GstCtx.cr4, (uint32_t)pVCpu->cpum.GstCtx.msrEFER));
            }
        }
        else if (pVM->cCpus == 1)
            Log(("NEMRx: -> NEMR3RunGC\n"));
        else
            Log(("NEMRx-CPU%u: -> NEMR3RunGC\n",  pVCpu->idCpu));
#endif /* LOG_ENABLED */

        /*
         * Execute the code.
         */
        if (RT_LIKELY(emR3IsExecutionAllowed(pVM, pVCpu)))
        {
            STAM_PROFILE_ADV_STOP(&pVCpu->em.s.StatNEMEntry, a);
            STAM_REL_PROFILE_START(&pVCpu->em.s.StatNEMExec, x);
            rcStrict = NEMR3RunGC(pVM, pVCpu);
            STAM_REL_PROFILE_STOP(&pVCpu->em.s.StatNEMExec, x);
        }
        else
        {
            /* Give up this time slice; virtual time continues */
            STAM_PROFILE_ADV_STOP(&pVCpu->em.s.StatNEMEntry, a);
            STAM_REL_PROFILE_ADV_START(&pVCpu->em.s.StatCapped, u);
            RTThreadSleep(5);
            STAM_REL_PROFILE_ADV_STOP(&pVCpu->em.s.StatCapped, u);
            rcStrict = VINF_SUCCESS;
        }


        /*
         * Deal with high priority post execution FFs before doing anything else.
         */
        VMCPU_FF_CLEAR_MASK(pVCpu, VMCPU_FF_RESUME_GUEST_MASK);
        if (   VM_FF_IS_ANY_SET(pVM, VM_FF_HIGH_PRIORITY_POST_MASK)
            || VMCPU_FF_IS_ANY_SET(pVCpu, VMCPU_FF_HIGH_PRIORITY_POST_MASK))
            rcStrict = emR3HighPriorityPostForcedActions(pVM, pVCpu, rcStrict);

        /*
         * Process the returned status code.
         */
        if (rcStrict >= VINF_EM_FIRST && rcStrict <= VINF_EM_LAST)
            break;

        rcStrict = emR3NemHandleRC(pVM, pVCpu, VBOXSTRICTRC_TODO(rcStrict));
        if (rcStrict != VINF_SUCCESS)
            break;

        /*
         * Check and execute forced actions.
         */
#ifdef VBOX_HIGH_RES_TIMERS_HACK
        TMTimerPollVoid(pVM, pVCpu);
#endif
        if (   VM_FF_IS_ANY_SET(pVM, VM_FF_ALL_MASK)
            || VMCPU_FF_IS_ANY_SET(pVCpu, VMCPU_FF_ALL_MASK))
        {
            rcStrict = emR3ForcedActions(pVM, pVCpu, VBOXSTRICTRC_TODO(rcStrict));
            VBOXVMM_EM_FF_ALL_RET(pVCpu, VBOXSTRICTRC_VAL(rcStrict));
            if (   rcStrict != VINF_SUCCESS
                && rcStrict != VINF_EM_RESCHEDULE_HM)
            {
                *pfFFDone = true;
                break;
            }
        }
    }

    /*
     * Return to outer loop, making sure the fetch all state as we leave.
     *
     * Note! Not using CPUM_IMPORT_EXTRN_RET here, to prioritize an rcStrict error
     *       status over import errors.
     */
    if (pVCpu->cpum.GstCtx.fExtrn)
    {
        int rcImport = NEMImportStateOnDemand(pVCpu, pVCpu->cpum.GstCtx.fExtrn);
        AssertReturn(RT_SUCCESS(rcImport) || RT_FAILURE_NP(rcStrict), rcImport);
    }
#if defined(LOG_ENABLED) && defined(DEBUG)
    RTLogFlush(NULL);
#endif
    return rcStrict;
}