PDMAllCritSect.cpp@ 93762

Last change on this file since 93762 was 93725, checked in by vboxsync, 3 years ago
VMM: More arm64 adjustments. bugref:9898
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1	/* $Id: PDMAllCritSect.cpp 93725 2022-02-14 13:46:16Z vboxsync $ */
2	/** @file
3	* PDM - Write-Only Critical Section, All Contexts.
4	*/
5
6	/*
7	* Copyright (C) 2006-2022 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*/
17
18
19	/*********************************************************************************************************************************
20	* Header Files *
21	*********************************************************************************************************************************/
22	#define LOG_GROUP LOG_GROUP_PDM_CRITSECT
23	#include "PDMInternal.h"
24	#include <VBox/vmm/pdmcritsect.h>
25	#include <VBox/vmm/mm.h>
26	#include <VBox/vmm/vmm.h>
27	#include <VBox/vmm/vmcc.h>
28	#include <VBox/err.h>
29	#include <VBox/vmm/hm.h>
30
31	#include <VBox/log.h>
32	#include <iprt/asm.h>
33	#include <iprt/assert.h>
34	#ifdef IN_RING3
35	# include <iprt/lockvalidator.h>
36	#endif
37	#if defined(IN_RING3) \|\| defined(IN_RING0)
38	# include <iprt/semaphore.h>
39	#endif
40	#ifdef IN_RING0
41	# include <iprt/time.h>
42	#endif
43	#if defined(IN_RING3) \|\| defined(IN_RING0)
44	# include <iprt/thread.h>
45	#endif
46
47
48	/*********************************************************************************************************************************
49	* Defined Constants And Macros *
50	*********************************************************************************************************************************/
51	/** The number loops to spin for in ring-3. */
52	#define PDMCRITSECT_SPIN_COUNT_R3 20
53	/** The number loops to spin for in ring-0. */
54	#define PDMCRITSECT_SPIN_COUNT_R0 256
55	/** The number loops to spin for in the raw-mode context. */
56	#define PDMCRITSECT_SPIN_COUNT_RC 256
57
58
59	/** Skips some of the overly paranoid atomic updates.
60	* Makes some assumptions about cache coherence, though not brave enough not to
61	* always end with an atomic update. */
62	#define PDMCRITSECT_WITH_LESS_ATOMIC_STUFF
63
64	/* Undefine the automatic VBOX_STRICT API mappings. */
65	#undef PDMCritSectEnter
66	#undef PDMCritSectTryEnter
67
68
69	/**
70	* Gets the ring-3 native thread handle of the calling thread.
71	*
72	* @returns native thread handle (ring-3).
73	* @param pVM The cross context VM structure.
74	* @param pCritSect The critical section. This is used in R0 and RC.
75	*/
76	DECL_FORCE_INLINE(RTNATIVETHREAD) pdmCritSectGetNativeSelf(PVMCC pVM, PCPDMCRITSECT pCritSect)
77	{
78	#ifdef IN_RING3
79	RT_NOREF(pVM, pCritSect);
80	RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
81
82	#elif defined(IN_RING0)
83	AssertMsgReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC, ("%RX32\n", pCritSect->s.Core.u32Magic),
84	NIL_RTNATIVETHREAD);
85	RTNATIVETHREAD hNativeSelf = GVMMR0GetRing3ThreadForSelf(pVM);
86	Assert(hNativeSelf != NIL_RTNATIVETHREAD);
87
88	#else
89	# error "Invalid context"
90	#endif
91	return hNativeSelf;
92	}
93
94
95	#ifdef IN_RING0
96	/**
97	* Marks the critical section as corrupted.
98	*/
99	DECL_NO_INLINE(static, int) pdmCritSectCorrupted(PPDMCRITSECT pCritSect, const char *pszMsg)
100	{
101	ASMAtomicWriteU32(&pCritSect->s.Core.u32Magic, PDMCRITSECT_MAGIC_CORRUPTED);
102	LogRel(("PDMCritSect: %s pCritSect=%p\n", pszMsg, pCritSect));
103	return VERR_PDM_CRITSECT_IPE;
104	}
105	#endif
106
107
108	/**
109	* Tail code called when we've won the battle for the lock.
110	*
111	* @returns VINF_SUCCESS.
112	*
113	* @param pCritSect The critical section.
114	* @param hNativeSelf The native handle of this thread.
115	* @param pSrcPos The source position of the lock operation.
116	*/
117	DECL_FORCE_INLINE(int) pdmCritSectEnterFirst(PPDMCRITSECT pCritSect, RTNATIVETHREAD hNativeSelf, PCRTLOCKVALSRCPOS pSrcPos)
118	{
119	Assert(hNativeSelf != NIL_RTNATIVETHREAD);
120	AssertMsg(pCritSect->s.Core.NativeThreadOwner == NIL_RTNATIVETHREAD, ("NativeThreadOwner=%p\n", pCritSect->s.Core.NativeThreadOwner));
121	Assert(!(pCritSect->s.Core.fFlags & PDMCRITSECT_FLAGS_PENDING_UNLOCK));
122
123	# ifdef PDMCRITSECT_WITH_LESS_ATOMIC_STUFF
124	pCritSect->s.Core.cNestings = 1;
125	# else
126	ASMAtomicWriteS32(&pCritSect->s.Core.cNestings, 1);
127	# endif
128	Assert(pCritSect->s.Core.cNestings == 1);
129	ASMAtomicWriteHandle(&pCritSect->s.Core.NativeThreadOwner, hNativeSelf);
130
131	# ifdef PDMCRITSECT_STRICT
132	RTLockValidatorRecExclSetOwner(pCritSect->s.Core.pValidatorRec, NIL_RTTHREAD, pSrcPos, true);
133	# else
134	NOREF(pSrcPos);
135	# endif
136	if (pSrcPos)
137	Log12Func(("%p: uId=%p ln=%u fn=%s\n", pCritSect, pSrcPos->uId, pSrcPos->uLine, pSrcPos->pszFunction));
138	else
139	Log12Func(("%p\n", pCritSect));
140
141	STAM_PROFILE_ADV_START(&pCritSect->s.StatLocked, l);
142	return VINF_SUCCESS;
143	}
144
145
146	#if defined(IN_RING3) \|\| defined(IN_RING0)
147	/**
148	* Deals with the contended case in ring-3 and ring-0.
149	*
150	* @retval VINF_SUCCESS on success.
151	* @retval VERR_SEM_DESTROYED if destroyed.
152	*
153	* @param pVM The cross context VM structure.
154	* @param pVCpu The cross context virtual CPU structure if ring-0 and on
155	* an EMT, otherwise NULL.
156	* @param pCritSect The critsect.
157	* @param hNativeSelf The native thread handle.
158	* @param pSrcPos The source position of the lock operation.
159	* @param rcBusy The status code to return when we're in RC or R0
160	*/
161	static int pdmR3R0CritSectEnterContended(PVMCC pVM, PVMCPU pVCpu, PPDMCRITSECT pCritSect, RTNATIVETHREAD hNativeSelf,
162	PCRTLOCKVALSRCPOS pSrcPos, int rcBusy)
163	{
164	# ifdef IN_RING0
165	/*
166	* If we've got queued critical section leave operations and rcBusy isn't
167	* VINF_SUCCESS, return to ring-3 immediately to avoid deadlocks.
168	*/
169	if ( !pVCpu
170	\|\| !VMCPU_FF_IS_SET(pVCpu, VMCPU_FF_PDM_CRITSECT)
171	\|\| rcBusy == VINF_SUCCESS )
172	{ /* likely */ }
173	else
174	{
175	/** @todo statistics. */
176	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionRZLock);
177	return rcBusy;
178	}
179	# endif
180
181	/*
182	* Start waiting.
183	*/
184	if (ASMAtomicIncS32(&pCritSect->s.Core.cLockers) == 0)
185	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
186	# ifdef IN_RING3
187	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionR3);
188	# else
189	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionRZLock);
190	# endif
191
192	/*
193	* The wait loop.
194	*
195	* This handles VERR_TIMEOUT and VERR_INTERRUPTED.
196	*/
197	STAM_REL_PROFILE_START(&pCritSect->s.CTX_MID_Z(StatContention,Wait), a);
198	PSUPDRVSESSION const pSession = pVM->pSession;
199	SUPSEMEVENT const hEvent = (SUPSEMEVENT)pCritSect->s.Core.EventSem;
200	# ifdef IN_RING3
201	# ifdef PDMCRITSECT_STRICT
202	RTTHREAD const hThreadSelf = RTThreadSelfAutoAdopt();
203	int rc2 = RTLockValidatorRecExclCheckOrder(pCritSect->s.Core.pValidatorRec, hThreadSelf, pSrcPos, RT_INDEFINITE_WAIT);
204	if (RT_FAILURE(rc2))
205	return rc2;
206	# else
207	RTTHREAD const hThreadSelf = RTThreadSelf();
208	# endif
209	# else /* IN_RING0 */
210	uint64_t const tsStart = RTTimeNanoTS();
211	uint64_t const cNsMaxTotalDef = RT_NS_5MIN;
212	uint64_t cNsMaxTotal = cNsMaxTotalDef;
213	uint64_t const cNsMaxRetry = RT_NS_15SEC;
214	uint32_t cMsMaxOne = RT_MS_5SEC;
215	bool fNonInterruptible = false;
216	# endif
217	for (;;)
218	{
219	/*
220	* Do the wait.
221	*
222	* In ring-3 this gets cluttered by lock validation and thread state
223	* maintainence.
224	*
225	* In ring-0 we have to deal with the possibility that the thread has
226	* been signalled and the interruptible wait function returning
227	* immediately. In that case we do normal R0/RC rcBusy handling.
228	*
229	* We always do a timed wait here, so the event handle is revalidated
230	* regularly and we won't end up stuck waiting for a destroyed critsect.
231	*/
232	/** @todo Make SUPSemEventClose wake up all waiters. */
233	# ifdef IN_RING3
234	# ifdef PDMCRITSECT_STRICT
235	int rc9 = RTLockValidatorRecExclCheckBlocking(pCritSect->s.Core.pValidatorRec, hThreadSelf, pSrcPos,
236	!(pCritSect->s.Core.fFlags & RTCRITSECT_FLAGS_NO_NESTING),
237	RT_INDEFINITE_WAIT, RTTHREADSTATE_CRITSECT, true);
238	if (RT_FAILURE(rc9))
239	return rc9;
240	# else
241	RTThreadBlocking(hThreadSelf, RTTHREADSTATE_CRITSECT, true);
242	# endif
243	int const rc = SUPSemEventWaitNoResume(pSession, hEvent, RT_MS_5SEC);
244	RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_CRITSECT);
245	# else /* IN_RING0 */
246	int const rc = !fNonInterruptible
247	? SUPSemEventWaitNoResume(pSession, hEvent, cMsMaxOne)
248	: SUPSemEventWait(pSession, hEvent, cMsMaxOne);
249	Log11Func(("%p: rc=%Rrc %'RU64 ns (cMsMaxOne=%RU64 hOwner=%p)\n",
250	pCritSect, rc, RTTimeNanoTS() - tsStart, cMsMaxOne, pCritSect->s.Core.NativeThreadOwner));
251	# endif /* IN_RING0 */
252
253	/*
254	* Make sure the critical section hasn't been delete before continuing.
255	*/
256	if (RT_LIKELY(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC))
257	{ /* likely */ }
258	else
259	{
260	LogRel(("PDMCritSectEnter: Destroyed while waiting; pCritSect=%p rc=%Rrc\n", pCritSect, rc));
261	return VERR_SEM_DESTROYED;
262	}
263
264	/*
265	* Most likely we're here because we got signalled.
266	*/
267	if (rc == VINF_SUCCESS)
268	{
269	STAM_REL_PROFILE_STOP(&pCritSect->s.CTX_MID_Z(StatContention,Wait), a);
270	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
271	}
272
273	/*
274	* Timeout and interrupted waits needs careful handling in ring-0
275	* because we're cooperating with ring-3 on this critical section
276	* and thus need to make absolutely sure we won't get stuck here.
277	*
278	* The r0 interrupted case means something is pending (termination,
279	* signal, APC, debugger, whatever), so we must try our best to
280	* return to the caller and to ring-3 so it can be dealt with.
281	*/
282	if (RT_LIKELY(rc == VERR_TIMEOUT \|\| rc == VERR_INTERRUPTED))
283	{
284	# ifdef IN_RING0
285	uint64_t const cNsElapsed = RTTimeNanoTS() - tsStart;
286	int const rcTerm = RTThreadQueryTerminationStatus(NIL_RTTHREAD);
287	AssertMsg(rcTerm == VINF_SUCCESS \|\| rcTerm == VERR_NOT_SUPPORTED \|\| rcTerm == VINF_THREAD_IS_TERMINATING,
288	("rcTerm=%Rrc\n", rcTerm));
289	if (rcTerm == VERR_NOT_SUPPORTED && cNsMaxTotal == cNsMaxTotalDef)
290	cNsMaxTotal = RT_NS_1MIN;
291
292	if (rc == VERR_TIMEOUT)
293	{
294	/* Try return get out of here with a non-VINF_SUCCESS status if
295	the thread is terminating or if the timeout has been exceeded. */
296	STAM_REL_COUNTER_INC(&pVM->pdm.s.StatCritSectVerrTimeout);
297	if ( rcTerm != VINF_THREAD_IS_TERMINATING
298	&& cNsElapsed <= cNsMaxTotal)
299	continue;
300	}
301	else
302	{
303	/* For interrupt cases, we must return if we can. If rcBusy is VINF_SUCCESS,
304	we will try non-interruptible sleep for a while to help resolve the issue
305	w/o guru'ing. */
306	STAM_REL_COUNTER_INC(&pVM->pdm.s.StatCritSectVerrInterrupted);
307	if ( rcTerm != VINF_THREAD_IS_TERMINATING
308	&& rcBusy == VINF_SUCCESS
309	&& pVCpu != NULL
310	&& cNsElapsed <= cNsMaxTotal)
311	{
312	if (!fNonInterruptible)
313	{
314	STAM_REL_COUNTER_INC(&pVM->pdm.s.StatCritSectNonInterruptibleWaits);
315	fNonInterruptible = true;
316	cMsMaxOne = 32;
317	uint64_t cNsLeft = cNsMaxTotal - cNsElapsed;
318	if (cNsLeft > RT_NS_10SEC)
319	cNsMaxTotal = cNsElapsed + RT_NS_10SEC;
320	}
321	continue;
322	}
323	}
324
325	/*
326	* Let try get out of here. We must very carefully undo the
327	* cLockers increment we did using compare-and-exchange so that
328	* we don't race the semaphore signalling in PDMCritSectLeave
329	* and end up with spurious wakeups and two owners at once.
330	*/
331	uint32_t cNoIntWaits = 0;
332	uint32_t cCmpXchgs = 0;
333	int32_t cLockers = ASMAtomicReadS32(&pCritSect->s.Core.cLockers);
334	for (;;)
335	{
336	if (pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC)
337	{
338	if (cLockers > 0 && cCmpXchgs < _64M)
339	{
340	bool fRc = ASMAtomicCmpXchgExS32(&pCritSect->s.Core.cLockers, cLockers - 1, cLockers, &cLockers);
341	if (fRc)
342	{
343	LogFunc(("Aborting wait on %p (rc=%Rrc rcTerm=%Rrc cNsElapsed=%'RU64) -> %Rrc\n", pCritSect,
344	rc, rcTerm, cNsElapsed, rcBusy != VINF_SUCCESS ? rcBusy : rc));
345	STAM_REL_COUNTER_INC(&pVM->pdm.s.StatAbortedCritSectEnters);
346	return rcBusy != VINF_SUCCESS ? rcBusy : rc;
347	}
348	cCmpXchgs++;
349	if ((cCmpXchgs & 0xffff) == 0)
350	Log11Func(("%p: cLockers=%d cCmpXchgs=%u (hOwner=%p)\n",
351	pCritSect, cLockers, cCmpXchgs, pCritSect->s.Core.NativeThreadOwner));
352	ASMNopPause();
353	continue;
354	}
355
356	if (cLockers == 0)
357	{
358	/*
359	* We are racing someone in PDMCritSectLeave.
360	*
361	* For the VERR_TIMEOUT case we'll just retry taking it the normal
362	* way for a while. For VERR_INTERRUPTED we're in for more fun as
363	* the previous owner might not have signalled the semaphore yet,
364	* so we'll do a short non-interruptible wait instead and then guru.
365	*/
366	if ( rc == VERR_TIMEOUT
367	&& RTTimeNanoTS() - tsStart <= cNsMaxTotal + cNsMaxRetry)
368	break;
369
370	if ( rc == VERR_INTERRUPTED
371	&& ( cNoIntWaits == 0
372	\|\| RTTimeNanoTS() - (tsStart + cNsElapsed) < RT_NS_100MS))
373	{
374	int const rc2 = SUPSemEventWait(pSession, hEvent, 1 /ms/);
375	if (rc2 == VINF_SUCCESS)
376	{
377	STAM_REL_COUNTER_INC(&pVM->pdm.s.StatCritSectEntersWhileAborting);
378	STAM_REL_PROFILE_STOP(&pCritSect->s.CTX_MID_Z(StatContention,Wait), a);
379	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
380	}
381	cNoIntWaits++;
382	cLockers = ASMAtomicReadS32(&pCritSect->s.Core.cLockers);
383	continue;
384	}
385	}
386	else
387	LogFunc(("Critical section %p has a broken cLockers count. Aborting.\n", pCritSect));
388
389	/* Sabotage the critical section and return error to caller. */
390	ASMAtomicWriteU32(&pCritSect->s.Core.u32Magic, PDMCRITSECT_MAGIC_FAILED_ABORT);
391	LogRel(("PDMCritSectEnter: Failed to abort wait on pCritSect=%p (rc=%Rrc rcTerm=%Rrc)\n",
392	pCritSect, rc, rcTerm));
393	return VERR_PDM_CRITSECT_ABORT_FAILED;
394	}
395	LogRel(("PDMCritSectEnter: Destroyed while aborting wait; pCritSect=%p/%#x rc=%Rrc rcTerm=%Rrc\n",
396	pCritSect, pCritSect->s.Core.u32Magic, rc, rcTerm));
397	return VERR_SEM_DESTROYED;
398	}
399
400	/* We get here if we timed out. Just retry now that it
401	appears someone left already. */
402	Assert(rc == VERR_TIMEOUT);
403	cMsMaxOne = 10 /ms/;
404
405	# else /* IN_RING3 */
406	RT_NOREF(pVM, pVCpu, rcBusy);
407	# endif /* IN_RING3 */
408	}
409	/*
410	* Any other return code is fatal.
411	*/
412	else
413	{
414	AssertMsgFailed(("rc=%Rrc\n", rc));
415	return RT_FAILURE_NP(rc) ? rc : -rc;
416	}
417	}
418	/* won't get here */
419	}
420	#endif /* IN_RING3 \|\| IN_RING0 */
421
422
423	/**
424	* Common worker for the debug and normal APIs.
425	*
426	* @returns VINF_SUCCESS if entered successfully.
427	* @returns rcBusy when encountering a busy critical section in RC/R0.
428	* @retval VERR_SEM_DESTROYED if the critical section is delete before or
429	* during the operation.
430	*
431	* @param pVM The cross context VM structure.
432	* @param pCritSect The PDM critical section to enter.
433	* @param rcBusy The status code to return when we're in RC or R0
434	* @param pSrcPos The source position of the lock operation.
435	*/
436	DECL_FORCE_INLINE(int) pdmCritSectEnter(PVMCC pVM, PPDMCRITSECT pCritSect, int rcBusy, PCRTLOCKVALSRCPOS pSrcPos)
437	{
438	Assert(pCritSect->s.Core.cNestings < 8); /* useful to catch incorrect locking */
439	Assert(pCritSect->s.Core.cNestings >= 0);
440	#if defined(VBOX_STRICT) && defined(IN_RING0)
441	/* Hope we're not messing with critical sections while in the no-block
442	zone, that would complicate things a lot. */
443	PVMCPUCC pVCpuAssert = VMMGetCpu(pVM);
444	Assert(pVCpuAssert && VMMRZCallRing3IsEnabled(pVCpuAssert));
445	#endif
446
447	/*
448	* If the critical section has already been destroyed, then inform the caller.
449	*/
450	AssertMsgReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC,
451	("%p %RX32\n", pCritSect, pCritSect->s.Core.u32Magic),
452	VERR_SEM_DESTROYED);
453
454	/*
455	* See if we're lucky.
456	*/
457	/* NOP ... */
458	if (!(pCritSect->s.Core.fFlags & RTCRITSECT_FLAGS_NOP))
459	{ /* We're more likely to end up here with real critsects than a NOP one. */ }
460	else
461	return VINF_SUCCESS;
462
463	RTNATIVETHREAD hNativeSelf = pdmCritSectGetNativeSelf(pVM, pCritSect);
464	AssertReturn(hNativeSelf != NIL_RTNATIVETHREAD, VERR_VM_THREAD_NOT_EMT);
465	/* ... not owned ... */
466	if (ASMAtomicCmpXchgS32(&pCritSect->s.Core.cLockers, 0, -1))
467	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
468
469	/* ... or nested. */
470	if (pCritSect->s.Core.NativeThreadOwner == hNativeSelf)
471	{
472	Assert(pCritSect->s.Core.cNestings >= 1);
473	# ifdef PDMCRITSECT_WITH_LESS_ATOMIC_STUFF
474	pCritSect->s.Core.cNestings += 1;
475	# else
476	ASMAtomicIncS32(&pCritSect->s.Core.cNestings);
477	# endif
478	ASMAtomicIncS32(&pCritSect->s.Core.cLockers);
479	Log12Func(("%p: cNestings=%d cLockers=%d\n", pCritSect, pCritSect->s.Core.cNestings, pCritSect->s.Core.cLockers));
480	return VINF_SUCCESS;
481	}
482
483	/*
484	* Spin for a bit without incrementing the counter.
485	*/
486	/** @todo Move this to cfgm variables since it doesn't make sense to spin on UNI
487	* cpu systems. */
488	int32_t cSpinsLeft = CTX_SUFF(PDMCRITSECT_SPIN_COUNT_);
489	while (cSpinsLeft-- > 0)
490	{
491	if (ASMAtomicCmpXchgS32(&pCritSect->s.Core.cLockers, 0, -1))
492	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
493	ASMNopPause();
494	/** @todo Should use monitor/mwait on e.g. &cLockers here, possibly with a
495	cli'ed pendingpreemption check up front using sti w/ instruction fusing
496	for avoiding races. Hmm ... This is assuming the other party is actually
497	executing code on another CPU ... which we could keep track of if we
498	wanted. */
499	}
500
501	#ifdef IN_RING3
502	/*
503	* Take the slow path.
504	*/
505	NOREF(rcBusy);
506	return pdmR3R0CritSectEnterContended(pVM, NULL, pCritSect, hNativeSelf, pSrcPos, rcBusy);
507
508	#elif defined(IN_RING0)
509	# if 1 /* new code */
510	/*
511	* In ring-0 context we have to take the special VT-x/AMD-V HM context into
512	* account when waiting on contended locks.
513	*
514	* While we usually (it can be VINF_SUCCESS) have the option of returning
515	* rcBusy and force the caller to go back to ring-3 and to re-start the work
516	* there, it's almost always more efficient to try wait for the lock here.
517	* The rcBusy will be used if we encounter an VERR_INTERRUPTED situation
518	* though.
519	*/
520	PVMCPUCC pVCpu = VMMGetCpu(pVM);
521	if (pVCpu)
522	{
523	VMMR0EMTBLOCKCTX Ctx;
524	int rc = VMMR0EmtPrepareToBlock(pVCpu, rcBusy, __FUNCTION__, pCritSect, &Ctx);
525	if (rc == VINF_SUCCESS)
526	{
527	Assert(RTThreadPreemptIsEnabled(NIL_RTTHREAD));
528
529	rc = pdmR3R0CritSectEnterContended(pVM, pVCpu, pCritSect, hNativeSelf, pSrcPos, rcBusy);
530
531	VMMR0EmtResumeAfterBlocking(pVCpu, &Ctx);
532	}
533	else
534	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionRZLockBusy);
535	return rc;
536	}
537
538	/* Non-EMT. */
539	Assert(RTThreadPreemptIsEnabled(NIL_RTTHREAD));
540	return pdmR3R0CritSectEnterContended(pVM, NULL, pCritSect, hNativeSelf, pSrcPos, rcBusy);
541
542	# else /* old code: */
543	/*
544	* We preemption hasn't been disabled, we can block here in ring-0.
545	*/
546	if ( RTThreadPreemptIsEnabled(NIL_RTTHREAD)
547	&& ASMIntAreEnabled())
548	return pdmR3R0CritSectEnterContended(pVM, VMMGetCpu(pVM), pCritSect, hNativeSelf, pSrcPos, rcBusy);
549
550	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionRZLock);
551
552	/*
553	* Call ring-3 to acquire the critical section?
554	*/
555	if (rcBusy == VINF_SUCCESS)
556	{
557	PVMCPUCC pVCpu = VMMGetCpu(pVM);
558	AssertReturn(pVCpu, VERR_PDM_CRITSECT_IPE);
559	return VMMRZCallRing3(pVM, pVCpu, VMMCALLRING3_PDM_CRIT_SECT_ENTER, MMHyperCCToR3(pVM, pCritSect));
560	}
561
562	/*
563	* Return busy.
564	*/
565	LogFlow(("PDMCritSectEnter: locked => R3 (%Rrc)\n", rcBusy));
566	return rcBusy;
567	# endif /* old code */
568	#else
569	# error "Unsupported context"
570	#endif
571	}
572
573
574	/**
575	* Enters a PDM critical section.
576	*
577	* @returns VINF_SUCCESS if entered successfully.
578	* @returns rcBusy when encountering a busy critical section in RC/R0.
579	* @retval VERR_SEM_DESTROYED if the critical section is delete before or
580	* during the operation.
581	*
582	* @param pVM The cross context VM structure.
583	* @param pCritSect The PDM critical section to enter.
584	* @param rcBusy The status code to return when we're in RC or R0
585	* and the section is busy. Pass VINF_SUCCESS to
586	* acquired the critical section thru a ring-3
587	* call if necessary.
588	*
589	* @note Even callers setting @a rcBusy to VINF_SUCCESS must either handle
590	* possible failures in ring-0 or apply
591	* PDM_CRITSECT_RELEASE_ASSERT_RC(),
592	* PDM_CRITSECT_RELEASE_ASSERT_RC_DEV(),
593	* PDM_CRITSECT_RELEASE_ASSERT_RC_DRV() or
594	* PDM_CRITSECT_RELEASE_ASSERT_RC_USB() to the return value of this
595	* function.
596	*/
597	VMMDECL(DECL_CHECK_RETURN_NOT_R3(int)) PDMCritSectEnter(PVMCC pVM, PPDMCRITSECT pCritSect, int rcBusy)
598	{
599	#ifndef PDMCRITSECT_STRICT
600	return pdmCritSectEnter(pVM, pCritSect, rcBusy, NULL);
601	#else
602	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
603	return pdmCritSectEnter(pVM, pCritSect, rcBusy, &SrcPos);
604	#endif
605	}
606
607
608	/**
609	* Enters a PDM critical section, with location information for debugging.
610	*
611	* @returns VINF_SUCCESS if entered successfully.
612	* @returns rcBusy when encountering a busy critical section in RC/R0.
613	* @retval VERR_SEM_DESTROYED if the critical section is delete before or
614	* during the operation.
615	*
616	* @param pVM The cross context VM structure.
617	* @param pCritSect The PDM critical section to enter.
618	* @param rcBusy The status code to return when we're in RC or R0
619	* and the section is busy. Pass VINF_SUCCESS to
620	* acquired the critical section thru a ring-3
621	* call if necessary.
622	* @param uId Some kind of locking location ID. Typically a
623	* return address up the stack. Optional (0).
624	* @param SRC_POS The source position where to lock is being
625	* acquired from. Optional.
626	*/
627	VMMDECL(DECL_CHECK_RETURN_NOT_R3(int))
628	PDMCritSectEnterDebug(PVMCC pVM, PPDMCRITSECT pCritSect, int rcBusy, RTHCUINTPTR uId, RT_SRC_POS_DECL)
629	{
630	#ifdef PDMCRITSECT_STRICT
631	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
632	return pdmCritSectEnter(pVM, pCritSect, rcBusy, &SrcPos);
633	#else
634	NOREF(uId); RT_SRC_POS_NOREF();
635	return pdmCritSectEnter(pVM, pCritSect, rcBusy, NULL);
636	#endif
637	}
638
639
640	/**
641	* Common worker for the debug and normal APIs.
642	*
643	* @retval VINF_SUCCESS on success.
644	* @retval VERR_SEM_BUSY if the critsect was owned.
645	* @retval VERR_SEM_NESTED if nested enter on a no nesting section. (Asserted.)
646	* @retval VERR_SEM_DESTROYED if the critical section is delete before or
647	* during the operation.
648	*
649	* @param pVM The cross context VM structure.
650	* @param pCritSect The critical section.
651	* @param pSrcPos The source position of the lock operation.
652	*/
653	static int pdmCritSectTryEnter(PVMCC pVM, PPDMCRITSECT pCritSect, PCRTLOCKVALSRCPOS pSrcPos)
654	{
655	/*
656	* If the critical section has already been destroyed, then inform the caller.
657	*/
658	AssertMsgReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC,
659	("%p %RX32\n", pCritSect, pCritSect->s.Core.u32Magic),
660	VERR_SEM_DESTROYED);
661
662	/*
663	* See if we're lucky.
664	*/
665	/* NOP ... */
666	if (!(pCritSect->s.Core.fFlags & RTCRITSECT_FLAGS_NOP))
667	{ /* We're more likely to end up here with real critsects than a NOP one. */ }
668	else
669	return VINF_SUCCESS;
670
671	RTNATIVETHREAD hNativeSelf = pdmCritSectGetNativeSelf(pVM, pCritSect);
672	AssertReturn(hNativeSelf != NIL_RTNATIVETHREAD, VERR_VM_THREAD_NOT_EMT);
673	/* ... not owned ... */
674	if (ASMAtomicCmpXchgS32(&pCritSect->s.Core.cLockers, 0, -1))
675	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
676
677	/* ... or nested. */
678	if (pCritSect->s.Core.NativeThreadOwner == hNativeSelf)
679	{
680	Assert(pCritSect->s.Core.cNestings >= 1);
681	# ifdef PDMCRITSECT_WITH_LESS_ATOMIC_STUFF
682	pCritSect->s.Core.cNestings += 1;
683	# else
684	ASMAtomicIncS32(&pCritSect->s.Core.cNestings);
685	# endif
686	ASMAtomicIncS32(&pCritSect->s.Core.cLockers);
687	Log12Func(("%p: cNestings=%d cLockers=%d\n", pCritSect, pCritSect->s.Core.cNestings, pCritSect->s.Core.cLockers));
688	return VINF_SUCCESS;
689	}
690
691	/* no spinning */
692
693	/*
694	* Return busy.
695	*/
696	#ifdef IN_RING3
697	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionR3);
698	#else
699	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionRZLockBusy);
700	#endif
701	LogFlow(("PDMCritSectTryEnter: locked\n"));
702	return VERR_SEM_BUSY;
703	}
704
705
706	/**
707	* Try enter a critical section.
708	*
709	* @retval VINF_SUCCESS on success.
710	* @retval VERR_SEM_BUSY if the critsect was owned.
711	* @retval VERR_SEM_NESTED if nested enter on a no nesting section. (Asserted.)
712	* @retval VERR_SEM_DESTROYED if the critical section is delete before or
713	* during the operation.
714	*
715	* @param pVM The cross context VM structure.
716	* @param pCritSect The critical section.
717	*/
718	VMMDECL(DECL_CHECK_RETURN(int)) PDMCritSectTryEnter(PVMCC pVM, PPDMCRITSECT pCritSect)
719	{
720	#ifndef PDMCRITSECT_STRICT
721	return pdmCritSectTryEnter(pVM, pCritSect, NULL);
722	#else
723	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
724	return pdmCritSectTryEnter(pVM, pCritSect, &SrcPos);
725	#endif
726	}
727
728
729	/**
730	* Try enter a critical section, with location information for debugging.
731	*
732	* @retval VINF_SUCCESS on success.
733	* @retval VERR_SEM_BUSY if the critsect was owned.
734	* @retval VERR_SEM_NESTED if nested enter on a no nesting section. (Asserted.)
735	* @retval VERR_SEM_DESTROYED if the critical section is delete before or
736	* during the operation.
737	*
738	* @param pVM The cross context VM structure.
739	* @param pCritSect The critical section.
740	* @param uId Some kind of locking location ID. Typically a
741	* return address up the stack. Optional (0).
742	* @param SRC_POS The source position where to lock is being
743	* acquired from. Optional.
744	*/
745	VMMDECL(DECL_CHECK_RETURN(int))
746	PDMCritSectTryEnterDebug(PVMCC pVM, PPDMCRITSECT pCritSect, RTHCUINTPTR uId, RT_SRC_POS_DECL)
747	{
748	#ifdef PDMCRITSECT_STRICT
749	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
750	return pdmCritSectTryEnter(pVM, pCritSect, &SrcPos);
751	#else
752	NOREF(uId); RT_SRC_POS_NOREF();
753	return pdmCritSectTryEnter(pVM, pCritSect, NULL);
754	#endif
755	}
756
757
758	#ifdef IN_RING3
759	/**
760	* Enters a PDM critical section.
761	*
762	* @returns VINF_SUCCESS if entered successfully.
763	* @returns rcBusy when encountering a busy critical section in GC/R0.
764	* @retval VERR_SEM_DESTROYED if the critical section is delete before or
765	* during the operation.
766	*
767	* @param pVM The cross context VM structure.
768	* @param pCritSect The PDM critical section to enter.
769	* @param fCallRing3 Whether this is a VMMRZCallRing3()request.
770	*/
771	VMMR3DECL(int) PDMR3CritSectEnterEx(PVM pVM, PPDMCRITSECT pCritSect, bool fCallRing3)
772	{
773	int rc = PDMCritSectEnter(pVM, pCritSect, VERR_IGNORED);
774	if ( rc == VINF_SUCCESS
775	&& fCallRing3
776	&& pCritSect->s.Core.pValidatorRec
777	&& pCritSect->s.Core.pValidatorRec->hThread != NIL_RTTHREAD)
778	RTLockValidatorRecExclReleaseOwnerUnchecked(pCritSect->s.Core.pValidatorRec);
779	return rc;
780	}
781	#endif /* IN_RING3 */
782
783
784	/**
785	* Leaves a critical section entered with PDMCritSectEnter().
786	*
787	* @returns Indication whether we really exited the critical section.
788	* @retval VINF_SUCCESS if we really exited.
789	* @retval VINF_SEM_NESTED if we only reduced the nesting count.
790	* @retval VERR_NOT_OWNER if you somehow ignore release assertions.
791	*
792	* @param pVM The cross context VM structure.
793	* @param pCritSect The PDM critical section to leave.
794	*
795	* @remarks Can be called from no-ring-3-call context in ring-0 (TM/VirtualSync)
796	* where we'll queue leaving operation for ring-3 processing.
797	*/
798	VMMDECL(int) PDMCritSectLeave(PVMCC pVM, PPDMCRITSECT pCritSect)
799	{
800	AssertMsg(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC, ("%p %RX32\n", pCritSect, pCritSect->s.Core.u32Magic));
801	Assert(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC);
802
803	/*
804	* Check for NOP sections before asserting ownership.
805	*/
806	if (!(pCritSect->s.Core.fFlags & RTCRITSECT_FLAGS_NOP))
807	{ /* We're more likely to end up here with real critsects than a NOP one. */ }
808	else
809	return VINF_SUCCESS;
810
811	/*
812	* Always check that the caller is the owner (screw performance).
813	*/
814	RTNATIVETHREAD const hNativeSelf = pdmCritSectGetNativeSelf(pVM, pCritSect);
815	VMM_ASSERT_RELEASE_MSG_RETURN(pVM, pCritSect->s.Core.NativeThreadOwner == hNativeSelf && hNativeSelf != NIL_RTNATIVETHREAD,
816	("%p %s: %p != %p; cLockers=%d cNestings=%d\n", pCritSect, R3STRING(pCritSect->s.pszName),
817	pCritSect->s.Core.NativeThreadOwner, hNativeSelf,
818	pCritSect->s.Core.cLockers, pCritSect->s.Core.cNestings),
819	VERR_NOT_OWNER);
820
821	/*
822	* Nested leave.
823	*/
824	int32_t const cNestings = pCritSect->s.Core.cNestings;
825	Assert(cNestings >= 1);
826	if (cNestings > 1)
827	{
828	#ifdef PDMCRITSECT_WITH_LESS_ATOMIC_STUFF
829	pCritSect->s.Core.cNestings = cNestings - 1;
830	#else
831	ASMAtomicWriteS32(&pCritSect->s.Core.cNestings, cNestings - 1);
832	#endif
833	int32_t const cLockers = ASMAtomicDecS32(&pCritSect->s.Core.cLockers);
834	Assert(cLockers >= 0); RT_NOREF(cLockers);
835	Log12Func(("%p: cNestings=%d cLockers=%d\n", pCritSect, cNestings - 1, cLockers));
836	return VINF_SEM_NESTED;
837	}
838
839	Log12Func(("%p: cNestings=%d cLockers=%d hOwner=%p - leave for real\n",
840	pCritSect, cNestings, pCritSect->s.Core.cLockers, pCritSect->s.Core.NativeThreadOwner));
841
842	#ifdef IN_RING3
843	/*
844	* Ring-3: Leave for real.
845	*/
846	SUPSEMEVENT const hEventToSignal = pCritSect->s.hEventToSignal;
847	pCritSect->s.hEventToSignal = NIL_SUPSEMEVENT;
848
849	# if defined(PDMCRITSECT_STRICT)
850	if (pCritSect->s.Core.pValidatorRec->hThread != NIL_RTTHREAD)
851	RTLockValidatorRecExclReleaseOwnerUnchecked(pCritSect->s.Core.pValidatorRec);
852	# endif
853	Assert(!pCritSect->s.Core.pValidatorRec \|\| pCritSect->s.Core.pValidatorRec->hThread == NIL_RTTHREAD);
854
855	# ifdef PDMCRITSECT_WITH_LESS_ATOMIC_STUFF
856	//pCritSect->s.Core.cNestings = 0; /* not really needed */
857	pCritSect->s.Core.NativeThreadOwner = NIL_RTNATIVETHREAD;
858	# else
859	ASMAtomicWriteS32(&pCritSect->s.Core.cNestings, 0);
860	ASMAtomicWriteHandle(&pCritSect->s.Core.NativeThreadOwner, NIL_RTNATIVETHREAD);
861	# endif
862	ASMAtomicAndU32(&pCritSect->s.Core.fFlags, ~PDMCRITSECT_FLAGS_PENDING_UNLOCK);
863
864	/* Stop profiling and decrement lockers. */
865	STAM_PROFILE_ADV_STOP(&pCritSect->s.StatLocked, l);
866	ASMCompilerBarrier();
867	int32_t const cLockers = ASMAtomicDecS32(&pCritSect->s.Core.cLockers);
868	if (cLockers < 0)
869	AssertMsg(cLockers == -1, ("cLockers=%d\n", cLockers));
870	else
871	{
872	/* Someone is waiting, wake up one of them. */
873	Assert(cLockers < _8K);
874	Log8(("PDMCritSectLeave: Waking up %p (cLockers=%u)\n", pCritSect, cLockers));
875	SUPSEMEVENT hEvent = (SUPSEMEVENT)pCritSect->s.Core.EventSem;
876	int rc = SUPSemEventSignal(pVM->pSession, hEvent);
877	AssertRC(rc);
878	}
879
880	/* Signal exit event. */
881	if (RT_LIKELY(hEventToSignal == NIL_SUPSEMEVENT))
882	{ /* likely */ }
883	else
884	{
885	Log8(("PDMCritSectLeave: Signalling %#p (%p)\n", hEventToSignal, pCritSect));
886	int rc = SUPSemEventSignal(pVM->pSession, hEventToSignal);
887	AssertRC(rc);
888	}
889
890	return VINF_SUCCESS;
891
892
893	#elif defined(IN_RING0)
894	/*
895	* Ring-0: Try leave for real, depends on host and context.
896	*/
897	SUPSEMEVENT const hEventToSignal = pCritSect->s.hEventToSignal;
898	pCritSect->s.hEventToSignal = NIL_SUPSEMEVENT;
899	PVMCPUCC pVCpu = VMMGetCpu(pVM);
900	bool fQueueOnTrouble = false; /* Set this to true to test queueing. */
901	if ( pVCpu == NULL /* non-EMT access, if we implement it must be able to block */
902	\|\| VMMRZCallRing3IsEnabled(pVCpu)
903	\|\| RTSemEventIsSignalSafe()
904	\|\| ( VMMR0ThreadCtxHookIsEnabled(pVCpu) /* Doesn't matter if Signal() blocks if we have hooks, ... */
905	&& RTThreadPreemptIsEnabled(NIL_RTTHREAD) /* ... and preemption is still enabled, */
906	&& ASMIntAreEnabled()) /* ... and interrupts hasn't yet been disabled. Special pre-GC HM env. */
907	\|\| (fQueueOnTrouble = ( hEventToSignal == NIL_SUPSEMEVENT
908	&& ASMAtomicUoReadS32(&pCritSect->s.Core.cLockers) == 0)) )
909	{
910	pCritSect->s.hEventToSignal = NIL_SUPSEMEVENT;
911
912	# ifdef PDMCRITSECT_WITH_LESS_ATOMIC_STUFF
913	//pCritSect->s.Core.cNestings = 0; /* not really needed */
914	pCritSect->s.Core.NativeThreadOwner = NIL_RTNATIVETHREAD;
915	# else
916	ASMAtomicWriteS32(&pCritSect->s.Core.cNestings, 0);
917	ASMAtomicWriteHandle(&pCritSect->s.Core.NativeThreadOwner, NIL_RTNATIVETHREAD);
918	# endif
919	ASMAtomicAndU32(&pCritSect->s.Core.fFlags, ~PDMCRITSECT_FLAGS_PENDING_UNLOCK);
920
921	/*
922	* Stop profiling and decrement lockers.
923	*/
924	STAM_PROFILE_ADV_STOP(&pCritSect->s.StatLocked, l);
925	ASMCompilerBarrier();
926
927	bool fQueueIt = false;
928	int32_t cLockers;
929	if (!fQueueOnTrouble)
930	cLockers = ASMAtomicDecS32(&pCritSect->s.Core.cLockers);
931	else
932	{
933	cLockers = -1;
934	if (!ASMAtomicCmpXchgS32(&pCritSect->s.Core.cLockers, -1, 0))
935	fQueueIt = true;
936	}
937	if (!fQueueIt)
938	{
939	VMMR0EMTBLOCKCTX Ctx;
940	bool fLeaveCtx = false;
941	if (cLockers < 0)
942	AssertMsg(cLockers == -1, ("cLockers=%d\n", cLockers));
943	else
944	{
945	/* Someone is waiting, wake up one of them. */
946	Assert(cLockers < _8K);
947	SUPSEMEVENT hEvent = (SUPSEMEVENT)pCritSect->s.Core.EventSem;
948	if (!RTSemEventIsSignalSafe() && (pVCpu = VMMGetCpu(pVM)) != NULL)
949	{
950	int rc = VMMR0EmtPrepareToBlock(pVCpu, VINF_SUCCESS, __FUNCTION__, pCritSect, &Ctx);
951	VMM_ASSERT_RELEASE_MSG_RETURN(pVM, RT_SUCCESS(rc), ("rc=%Rrc\n", rc), rc);
952	fLeaveCtx = true;
953	}
954	int rc = SUPSemEventSignal(pVM->pSession, hEvent);
955	AssertRC(rc);
956	}
957
958	/*
959	* Signal exit event.
960	*/
961	if (RT_LIKELY(hEventToSignal == NIL_SUPSEMEVENT))
962	{ /* likely */ }
963	else
964	{
965	if (!fLeaveCtx && pVCpu != NULL && !RTSemEventIsSignalSafe() && (pVCpu = VMMGetCpu(pVM)) != NULL)
966	{
967	int rc = VMMR0EmtPrepareToBlock(pVCpu, VINF_SUCCESS, __FUNCTION__, pCritSect, &Ctx);
968	VMM_ASSERT_RELEASE_MSG_RETURN(pVM, RT_SUCCESS(rc), ("rc=%Rrc\n", rc), rc);
969	fLeaveCtx = true;
970	}
971	Log8(("Signalling %#p\n", hEventToSignal));
972	int rc = SUPSemEventSignal(pVM->pSession, hEventToSignal);
973	AssertRC(rc);
974	}
975
976	/*
977	* Restore HM context if needed.
978	*/
979	if (!fLeaveCtx)
980	{ /* contention should be unlikely */ }
981	else
982	VMMR0EmtResumeAfterBlocking(pVCpu, &Ctx);
983
984	# ifdef DEBUG_bird
985	VMMTrashVolatileXMMRegs();
986	# endif
987	return VINF_SUCCESS;
988	}
989
990	/*
991	* Darn, someone raced in on us. Restore the state (this works only
992	* because the semaphore is effectively controlling ownership).
993	*/
994	bool fRc;
995	RTNATIVETHREAD hMessOwner = NIL_RTNATIVETHREAD;
996	ASMAtomicCmpXchgExHandle(&pCritSect->s.Core.NativeThreadOwner, hNativeSelf, NIL_RTNATIVETHREAD, fRc, &hMessOwner);
997	AssertLogRelMsgReturn(fRc, ("pCritSect=%p hMessOwner=%p\n", pCritSect, hMessOwner),
998	pdmCritSectCorrupted(pCritSect, "owner race"));
999	STAM_PROFILE_ADV_START(&pCritSect->s.StatLocked, l);
1000	# ifdef PDMCRITSECT_WITH_LESS_ATOMIC_STUFF
1001	//pCritSect->s.Core.cNestings = 1;
1002	Assert(pCritSect->s.Core.cNestings == 1);
1003	# else
1004	//Assert(pCritSect->s.Core.cNestings == 0);
1005	ASMAtomicWriteS32(&pCritSect->s.Core.cNestings, 1);
1006	# endif
1007	Assert(hEventToSignal == NIL_SUPSEMEVENT);
1008	}
1009
1010
1011	#else /* IN_RC */
1012	/*
1013	* Raw-mode: Try leave it.
1014	*/
1015	# error "This context is not use..."
1016	if (pCritSect->s.Core.cLockers == 0)
1017	{
1018	# ifdef PDMCRITSECT_WITH_LESS_ATOMIC_STUFF
1019	//pCritSect->s.Core.cNestings = 0; /* not really needed */
1020	# else
1021	ASMAtomicWriteS32(&pCritSect->s.Core.cNestings, 0);
1022	# endif
1023	ASMAtomicAndU32(&pCritSect->s.Core.fFlags, ~PDMCRITSECT_FLAGS_PENDING_UNLOCK);
1024	STAM_PROFILE_ADV_STOP(&pCritSect->s.StatLocked, l);
1025
1026	ASMAtomicWriteHandle(&pCritSect->s.Core.NativeThreadOwner, NIL_RTNATIVETHREAD);
1027	if (ASMAtomicCmpXchgS32(&pCritSect->s.Core.cLockers, -1, 0))
1028	return VINF_SUCCESS;
1029
1030	/*
1031	* Darn, someone raced in on us. Restore the state (this works only
1032	* because the semaphore is effectively controlling ownership).
1033	*/
1034	bool fRc;
1035	RTNATIVETHREAD hMessOwner = NIL_RTNATIVETHREAD;
1036	ASMAtomicCmpXchgExHandle(&pCritSect->s.Core.NativeThreadOwner, hNativeSelf, NIL_RTNATIVETHREAD, fRc, &hMessOwner);
1037	AssertLogRelMsgReturn(fRc, ("pCritSect=%p hMessOwner=%p\n", pCritSect, hMessOwner),
1038	pdmCritSectCorrupted(pCritSect, "owner race"));
1039	STAM_PROFILE_ADV_START(&pCritSect->s.StatLocked, l);
1040	# ifdef PDMCRITSECT_WITH_LESS_ATOMIC_STUFF
1041	//pCritSect->s.Core.cNestings = 1;
1042	Assert(pCritSect->s.Core.cNestings == 1);
1043	# else
1044	//Assert(pCritSect->s.Core.cNestings == 0);
1045	ASMAtomicWriteS32(&pCritSect->s.Core.cNestings, 1);
1046	# endif
1047	}
1048	#endif /* IN_RC */
1049
1050
1051	#ifndef IN_RING3
1052	/*
1053	* Ring-0/raw-mode: Unable to leave. Queue the leave for ring-3.
1054	*/
1055	ASMAtomicOrU32(&pCritSect->s.Core.fFlags, PDMCRITSECT_FLAGS_PENDING_UNLOCK);
1056	# ifndef IN_RING0
1057	PVMCPUCC pVCpu = VMMGetCpu(pVM);
1058	# endif
1059	uint32_t i = pVCpu->pdm.s.cQueuedCritSectLeaves++;
1060	LogFlow(("PDMCritSectLeave: [%d]=%p => R3\n", i, pCritSect));
1061	VMM_ASSERT_RELEASE_MSG_RETURN(pVM, i < RT_ELEMENTS(pVCpu->pdm.s.apQueuedCritSectLeaves), ("%d\n", i), VERR_PDM_CRITSECT_IPE);
1062	pVCpu->pdm.s.apQueuedCritSectLeaves[i] = pCritSect->s.pSelfR3;
1063	VMM_ASSERT_RELEASE_MSG_RETURN(pVM,
1064	RT_VALID_PTR(pVCpu->pdm.s.apQueuedCritSectLeaves[i])
1065	&& ((uintptr_t)pVCpu->pdm.s.apQueuedCritSectLeaves[i] & HOST_PAGE_OFFSET_MASK)
1066	== ((uintptr_t)pCritSect & HOST_PAGE_OFFSET_MASK),
1067	("%p vs %p\n", pVCpu->pdm.s.apQueuedCritSectLeaves[i], pCritSect),
1068	pdmCritSectCorrupted(pCritSect, "Invalid pSelfR3 value"));
1069	VMCPU_FF_SET(pVCpu, VMCPU_FF_PDM_CRITSECT); /** @todo handle VMCPU_FF_PDM_CRITSECT in ring-0 outside the no-call-ring-3 part. */
1070	VMCPU_FF_SET(pVCpu, VMCPU_FF_TO_R3); /* unnecessary paranoia */
1071	STAM_REL_COUNTER_INC(&pVM->pdm.s.StatQueuedCritSectLeaves);
1072	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionRZUnlock);
1073
1074	return VINF_SUCCESS;
1075	#endif /* IN_RING3 */
1076	}
1077
1078
1079	#if defined(IN_RING0) \|\| defined(IN_RING3)
1080	/**
1081	* Schedule a event semaphore for signalling upon critsect exit.
1082	*
1083	* @returns VINF_SUCCESS on success.
1084	* @returns VERR_TOO_MANY_SEMAPHORES if an event was already scheduled.
1085	* @returns VERR_NOT_OWNER if we're not the critsect owner (ring-3 only).
1086	* @returns VERR_SEM_DESTROYED if RTCritSectDelete was called while waiting.
1087	*
1088	* @param pCritSect The critical section.
1089	* @param hEventToSignal The support driver event semaphore that should be
1090	* signalled.
1091	*/
1092	VMMDECL(int) PDMHCCritSectScheduleExitEvent(PPDMCRITSECT pCritSect, SUPSEMEVENT hEventToSignal)
1093	{
1094	AssertPtr(pCritSect);
1095	Assert(!(pCritSect->s.Core.fFlags & RTCRITSECT_FLAGS_NOP));
1096	Assert(hEventToSignal != NIL_SUPSEMEVENT);
1097	# ifdef IN_RING3
1098	if (RT_UNLIKELY(!RTCritSectIsOwner(&pCritSect->s.Core)))
1099	return VERR_NOT_OWNER;
1100	# endif
1101	if (RT_LIKELY( pCritSect->s.hEventToSignal == NIL_RTSEMEVENT
1102	\|\| pCritSect->s.hEventToSignal == hEventToSignal))
1103	{
1104	pCritSect->s.hEventToSignal = hEventToSignal;
1105	return VINF_SUCCESS;
1106	}
1107	return VERR_TOO_MANY_SEMAPHORES;
1108	}
1109	#endif /* IN_RING0 \|\| IN_RING3 */
1110
1111
1112	/**
1113	* Checks the caller is the owner of the critical section.
1114	*
1115	* @returns true if owner.
1116	* @returns false if not owner.
1117	* @param pVM The cross context VM structure.
1118	* @param pCritSect The critical section.
1119	*/
1120	VMMDECL(bool) PDMCritSectIsOwner(PVMCC pVM, PCPDMCRITSECT pCritSect)
1121	{
1122	#ifdef IN_RING3
1123	RT_NOREF(pVM);
1124	return RTCritSectIsOwner(&pCritSect->s.Core);
1125	#else
1126	PVMCPUCC pVCpu = VMMGetCpu(pVM);
1127	if ( !pVCpu
1128	\|\| pCritSect->s.Core.NativeThreadOwner != pVCpu->hNativeThread)
1129	return false;
1130	return (pCritSect->s.Core.fFlags & PDMCRITSECT_FLAGS_PENDING_UNLOCK) == 0
1131	\|\| pCritSect->s.Core.cNestings > 1;
1132	#endif
1133	}
1134
1135
1136	/**
1137	* Checks the specified VCPU is the owner of the critical section.
1138	*
1139	* @returns true if owner.
1140	* @returns false if not owner.
1141	* @param pVCpu The cross context virtual CPU structure.
1142	* @param pCritSect The critical section.
1143	*/
1144	VMMDECL(bool) PDMCritSectIsOwnerEx(PVMCPUCC pVCpu, PCPDMCRITSECT pCritSect)
1145	{
1146	#ifdef IN_RING3
1147	NOREF(pVCpu);
1148	return RTCritSectIsOwner(&pCritSect->s.Core);
1149	#else
1150	Assert(VMCC_GET_CPU(pVCpu->CTX_SUFF(pVM), pVCpu->idCpu) == pVCpu);
1151	if (pCritSect->s.Core.NativeThreadOwner != pVCpu->hNativeThread)
1152	return false;
1153	return (pCritSect->s.Core.fFlags & PDMCRITSECT_FLAGS_PENDING_UNLOCK) == 0
1154	\|\| pCritSect->s.Core.cNestings > 1;
1155	#endif
1156	}
1157
1158
1159	/**
1160	* Checks if anyone is waiting on the critical section we own.
1161	*
1162	* @returns true if someone is waiting.
1163	* @returns false if no one is waiting.
1164	* @param pVM The cross context VM structure.
1165	* @param pCritSect The critical section.
1166	*/
1167	VMMDECL(bool) PDMCritSectHasWaiters(PVMCC pVM, PCPDMCRITSECT pCritSect)
1168	{
1169	AssertReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC, false);
1170	Assert(pCritSect->s.Core.NativeThreadOwner == pdmCritSectGetNativeSelf(pVM, pCritSect)); RT_NOREF(pVM);
1171	return pCritSect->s.Core.cLockers >= pCritSect->s.Core.cNestings;
1172	}
1173
1174
1175	/**
1176	* Checks if a critical section is initialized or not.
1177	*
1178	* @returns true if initialized.
1179	* @returns false if not initialized.
1180	* @param pCritSect The critical section.
1181	*/
1182	VMMDECL(bool) PDMCritSectIsInitialized(PCPDMCRITSECT pCritSect)
1183	{
1184	return RTCritSectIsInitialized(&pCritSect->s.Core);
1185	}
1186
1187
1188	/**
1189	* Gets the recursion depth.
1190	*
1191	* @returns The recursion depth.
1192	* @param pCritSect The critical section.
1193	*/
1194	VMMDECL(uint32_t) PDMCritSectGetRecursion(PCPDMCRITSECT pCritSect)
1195	{
1196	return RTCritSectGetRecursion(&pCritSect->s.Core);
1197	}
1198

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source: vbox/trunk/src/VBox/VMM/VMMAll/PDMAllCritSect.cpp@ 93762

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