PDMAllCritSect.cpp@ 39012

Last change on this file since 39012 was 38944, checked in by vboxsync, 14 years ago
PDMCritSectLeave: Indicate whether it was a nested exit or a real one.
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1	/* $Id: PDMAllCritSect.cpp 38944 2011-10-05 14:03:53Z vboxsync $ */
2	/** @file
3	* PDM - Critical Sections, All Contexts.
4	*/
5
6	/*
7	* Copyright (C) 2006-2007 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/vm.h>
28	#include <VBox/err.h>
29	#include <VBox/vmm/hwaccm.h>
30
31	#include <VBox/log.h>
32	#include <iprt/asm.h>
33	#include <iprt/asm-amd64-x86.h>
34	#include <iprt/assert.h>
35	#ifdef IN_RING3
36	# include <iprt/lockvalidator.h>
37	# include <iprt/semaphore.h>
38	#endif
39	#if defined(IN_RING3) \|\| defined(IN_RING0)
40	# include <iprt/thread.h>
41	#endif
42
43
44	/*******************************************************************************
45	* Defined Constants And Macros *
46	*******************************************************************************/
47	/** The number loops to spin for in ring-3. */
48	#define PDMCRITSECT_SPIN_COUNT_R3 20
49	/** The number loops to spin for in ring-0. */
50	#define PDMCRITSECT_SPIN_COUNT_R0 256
51	/** The number loops to spin for in the raw-mode context. */
52	#define PDMCRITSECT_SPIN_COUNT_RC 256
53
54
55	/* Undefine the automatic VBOX_STRICT API mappings. */
56	#undef PDMCritSectEnter
57	#undef PDMCritSectTryEnter
58
59
60	/**
61	* Gets the ring-3 native thread handle of the calling thread.
62	*
63	* @returns native thread handle (ring-3).
64	* @param pCritSect The critical section. This is used in R0 and RC.
65	*/
66	DECL_FORCE_INLINE(RTNATIVETHREAD) pdmCritSectGetNativeSelf(PCPDMCRITSECT pCritSect)
67	{
68	#ifdef IN_RING3
69	NOREF(pCritSect);
70	RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
71	#else
72	AssertMsgReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC, ("%RX32\n", pCritSect->s.Core.u32Magic),
73	NIL_RTNATIVETHREAD);
74	PVM pVM = pCritSect->s.CTX_SUFF(pVM); AssertPtr(pVM);
75	PVMCPU pVCpu = VMMGetCpu(pVM); AssertPtr(pVCpu);
76	RTNATIVETHREAD hNativeSelf = pVCpu->hNativeThread; Assert(hNativeSelf != NIL_RTNATIVETHREAD);
77	#endif
78	return hNativeSelf;
79	}
80
81
82	/**
83	* Tail code called when we've won the battle for the lock.
84	*
85	* @returns VINF_SUCCESS.
86	*
87	* @param pCritSect The critical section.
88	* @param hNativeSelf The native handle of this thread.
89	*/
90	DECL_FORCE_INLINE(int) pdmCritSectEnterFirst(PPDMCRITSECT pCritSect, RTNATIVETHREAD hNativeSelf, PCRTLOCKVALSRCPOS pSrcPos)
91	{
92	AssertMsg(pCritSect->s.Core.NativeThreadOwner == NIL_RTNATIVETHREAD, ("NativeThreadOwner=%p\n", pCritSect->s.Core.NativeThreadOwner));
93	Assert(!(pCritSect->s.Core.fFlags & PDMCRITSECT_FLAGS_PENDING_UNLOCK));
94
95	ASMAtomicWriteS32(&pCritSect->s.Core.cNestings, 1);
96	Assert(pCritSect->s.Core.cNestings == 1);
97	ASMAtomicWriteHandle(&pCritSect->s.Core.NativeThreadOwner, hNativeSelf);
98
99	# ifdef PDMCRITSECT_STRICT
100	RTLockValidatorRecExclSetOwner(pCritSect->s.Core.pValidatorRec, NIL_RTTHREAD, pSrcPos, true);
101	# endif
102
103	STAM_PROFILE_ADV_START(&pCritSect->s.StatLocked, l);
104	return VINF_SUCCESS;
105	}
106
107
108	#if defined(IN_RING3) \|\| defined(IN_RING0)
109	/**
110	* Deals with the contended case in ring-3 and ring-0.
111	*
112	* @returns VINF_SUCCESS or VERR_SEM_DESTROYED.
113	* @param pCritSect The critsect.
114	* @param hNativeSelf The native thread handle.
115	*/
116	static int pdmR3R0CritSectEnterContended(PPDMCRITSECT pCritSect, RTNATIVETHREAD hNativeSelf, PCRTLOCKVALSRCPOS pSrcPos)
117	{
118	/*
119	* Start waiting.
120	*/
121	if (ASMAtomicIncS32(&pCritSect->s.Core.cLockers) == 0)
122	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
123	# ifdef IN_RING3
124	STAM_COUNTER_INC(&pCritSect->s.StatContentionR3);
125	# else
126	STAM_COUNTER_INC(&pCritSect->s.StatContentionRZLock);
127	# endif
128
129	/*
130	* The wait loop.
131	*/
132	PSUPDRVSESSION pSession = pCritSect->s.CTX_SUFF(pVM)->pSession;
133	SUPSEMEVENT hEvent = (SUPSEMEVENT)pCritSect->s.Core.EventSem;
134	# ifdef IN_RING3
135	# ifdef PDMCRITSECT_STRICT
136	RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
137	int rc2 = RTLockValidatorRecExclCheckOrder(pCritSect->s.Core.pValidatorRec, hThreadSelf, pSrcPos, RT_INDEFINITE_WAIT);
138	if (RT_FAILURE(rc2))
139	return rc2;
140	# else
141	RTTHREAD hThreadSelf = RTThreadSelf();
142	# endif
143	# endif
144	for (;;)
145	{
146	# ifdef PDMCRITSECT_STRICT
147	int rc9 = RTLockValidatorRecExclCheckBlocking(pCritSect->s.Core.pValidatorRec, hThreadSelf, pSrcPos,
148	!(pCritSect->s.Core.fFlags & RTCRITSECT_FLAGS_NO_NESTING),
149	RT_INDEFINITE_WAIT, RTTHREADSTATE_CRITSECT, true);
150	if (RT_FAILURE(rc9))
151	return rc9;
152	# elif defined(IN_RING3)
153	RTThreadBlocking(hThreadSelf, RTTHREADSTATE_CRITSECT, true);
154	# endif
155	int rc = SUPSemEventWaitNoResume(pSession, hEvent, RT_INDEFINITE_WAIT);
156	# ifdef IN_RING3
157	RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_CRITSECT);
158	# endif
159
160	if (RT_UNLIKELY(pCritSect->s.Core.u32Magic != RTCRITSECT_MAGIC))
161	return VERR_SEM_DESTROYED;
162	if (rc == VINF_SUCCESS)
163	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
164	AssertMsg(rc == VERR_INTERRUPTED, ("rc=%Rrc\n", rc));
165	}
166	/* won't get here */
167	}
168	#endif /* IN_RING3 \|\| IN_RING0 */
169
170
171	/**
172	* Common worker for the debug and normal APIs.
173	*
174	* @returns VINF_SUCCESS if entered successfully.
175	* @returns rcBusy when encountering a busy critical section in GC/R0.
176	* @returns VERR_SEM_DESTROYED if the critical section is dead.
177	*
178	* @param pCritSect The PDM critical section to enter.
179	* @param rcBusy The status code to return when we're in GC or R0
180	* and the section is busy.
181	*/
182	DECL_FORCE_INLINE(int) pdmCritSectEnter(PPDMCRITSECT pCritSect, int rcBusy, PCRTLOCKVALSRCPOS pSrcPos)
183	{
184	Assert(pCritSect->s.Core.cNestings < 8); /* useful to catch incorrect locking */
185	Assert(pCritSect->s.Core.cNestings >= 0);
186
187	/*
188	* If the critical section has already been destroyed, then inform the caller.
189	*/
190	AssertMsgReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC,
191	("%p %RX32\n", pCritSect, pCritSect->s.Core.u32Magic),
192	VERR_SEM_DESTROYED);
193
194	/*
195	* See if we're lucky.
196	*/
197	/* NOP ... */
198	if (pCritSect->s.Core.fFlags & RTCRITSECT_FLAGS_NOP)
199	return VINF_SUCCESS;
200
201	RTNATIVETHREAD hNativeSelf = pdmCritSectGetNativeSelf(pCritSect);
202	/* ... not owned ... */
203	if (ASMAtomicCmpXchgS32(&pCritSect->s.Core.cLockers, 0, -1))
204	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
205
206	/* ... or nested. */
207	if (pCritSect->s.Core.NativeThreadOwner == hNativeSelf)
208	{
209	ASMAtomicIncS32(&pCritSect->s.Core.cLockers);
210	ASMAtomicIncS32(&pCritSect->s.Core.cNestings);
211	Assert(pCritSect->s.Core.cNestings > 1);
212	return VINF_SUCCESS;
213	}
214
215	/*
216	* Spin for a bit without incrementing the counter.
217	*/
218	/** @todo Move this to cfgm variables since it doesn't make sense to spin on UNI
219	* cpu systems. */
220	int32_t cSpinsLeft = CTX_SUFF(PDMCRITSECT_SPIN_COUNT_);
221	while (cSpinsLeft-- > 0)
222	{
223	if (ASMAtomicCmpXchgS32(&pCritSect->s.Core.cLockers, 0, -1))
224	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
225	ASMNopPause();
226	/** @todo Should use monitor/mwait on e.g. &cLockers here, possibly with a
227	cli'ed pendingpreemption check up front using sti w/ instruction fusing
228	for avoiding races. Hmm ... This is assuming the other party is actually
229	executing code on another CPU ... which we could keep track of if we
230	wanted. */
231	}
232
233	#ifdef IN_RING3
234	/*
235	* Take the slow path.
236	*/
237	return pdmR3R0CritSectEnterContended(pCritSect, hNativeSelf, pSrcPos);
238
239	#else
240	# ifdef IN_RING0
241	/** @todo If preemption is disabled it means we're in VT-x/AMD-V context
242	* and would be better off switching out of that while waiting for
243	* the lock. Several of the locks jumps back to ring-3 just to
244	* get the lock, the ring-3 code will then call the kernel to do
245	* the lock wait and when the call return it will call ring-0
246	* again and resume via in setjmp style. Not very efficient. */
247	# if 0
248	if (ASMIntAreEnabled()) /** @todo this can be handled as well by changing
249	* callers not prepared for longjmp/blocking to
250	* use PDMCritSectTryEnter. */
251	{
252	/*
253	* Leave HWACCM context while waiting if necessary.
254	*/
255	int rc;
256	if (RTThreadPreemptIsEnabled(NIL_RTTHREAD))
257	{
258	STAM_REL_COUNTER_ADD(&pCritSect->s.StatContentionRZLock, 1000000);
259	rc = pdmR3R0CritSectEnterContended(pCritSect, hNativeSelf, pSrcPos);
260	}
261	else
262	{
263	STAM_REL_COUNTER_ADD(&pCritSect->s.StatContentionRZLock, 1000000000);
264	PVM pVM = pCritSect->s.CTX_SUFF(pVM);
265	PVMCPU pVCpu = VMMGetCpu(pVM);
266	HWACCMR0Leave(pVM, pVCpu);
267	RTThreadPreemptRestore(NIL_RTTHREAD, ????);
268
269	rc = pdmR3R0CritSectEnterContended(pCritSect, hNativeSelf, pSrcPos);
270
271	RTThreadPreemptDisable(NIL_RTTHREAD, ????);
272	HWACCMR0Enter(pVM, pVCpu);
273	}
274	return rc;
275	}
276	# else
277	/*
278	* We preemption hasn't been disabled, we can block here in ring-0.
279	*/
280	if ( RTThreadPreemptIsEnabled(NIL_RTTHREAD)
281	&& ASMIntAreEnabled())
282	return pdmR3R0CritSectEnterContended(pCritSect, hNativeSelf, pSrcPos);
283	# endif
284	#endif /* IN_RING0 */
285
286	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionRZLock);
287
288	/*
289	* Call ring-3 to acquire the critical section?
290	*/
291	if (rcBusy == VINF_SUCCESS)
292	{
293	PVM pVM = pCritSect->s.CTX_SUFF(pVM); AssertPtr(pVM);
294	PVMCPU pVCpu = VMMGetCpu(pVM); AssertPtr(pVCpu);
295	return VMMRZCallRing3(pVM, pVCpu, VMMCALLRING3_PDM_CRIT_SECT_ENTER, MMHyperCCToR3(pVM, pCritSect));
296	}
297
298	/*
299	* Return busy.
300	*/
301	LogFlow(("PDMCritSectEnter: locked => R3 (%Rrc)\n", rcBusy));
302	return rcBusy;
303	#endif /* !IN_RING3 */
304	}
305
306
307	/**
308	* Enters a PDM critical section.
309	*
310	* @returns VINF_SUCCESS if entered successfully.
311	* @returns rcBusy when encountering a busy critical section in GC/R0.
312	* @returns VERR_SEM_DESTROYED if the critical section is dead.
313	*
314	* @param pCritSect The PDM critical section to enter.
315	* @param rcBusy The status code to return when we're in GC or R0
316	* and the section is busy. Pass VINF_SUCCESS to
317	* acquired the critical section thru a ring-3
318	* call if necessary.
319	*/
320	VMMDECL(int) PDMCritSectEnter(PPDMCRITSECT pCritSect, int rcBusy)
321	{
322	#ifndef PDMCRITSECT_STRICT
323	return pdmCritSectEnter(pCritSect, rcBusy, NULL);
324	#else
325	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
326	return pdmCritSectEnter(pCritSect, rcBusy, &SrcPos);
327	#endif
328	}
329
330
331	/**
332	* Enters a PDM critical section, with location information for debugging.
333	*
334	* @returns VINF_SUCCESS if entered successfully.
335	* @returns rcBusy when encountering a busy critical section in GC/R0.
336	* @returns VERR_SEM_DESTROYED if the critical section is dead.
337	*
338	* @param pCritSect The PDM critical section to enter.
339	* @param rcBusy The status code to return when we're in GC or R0
340	* and the section is busy. Pass VINF_SUCCESS to
341	* acquired the critical section thru a ring-3
342	* call if necessary.
343	* @param uId Some kind of locking location ID. Typically a
344	* return address up the stack. Optional (0).
345	* @param pszFile The file where the lock is being acquired from.
346	* Optional.
347	* @param iLine The line number in that file. Optional (0).
348	* @param pszFunction The function where the lock is being acquired
349	* from. Optional.
350	*/
351	VMMDECL(int) PDMCritSectEnterDebug(PPDMCRITSECT pCritSect, int rcBusy, RTHCUINTPTR uId, RT_SRC_POS_DECL)
352	{
353	#ifdef PDMCRITSECT_STRICT
354	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
355	return pdmCritSectEnter(pCritSect, rcBusy, &SrcPos);
356	#else
357	return pdmCritSectEnter(pCritSect, rcBusy, NULL);
358	#endif
359	}
360
361
362	/**
363	* Common worker for the debug and normal APIs.
364	*
365	* @retval VINF_SUCCESS on success.
366	* @retval VERR_SEM_BUSY if the critsect was owned.
367	* @retval VERR_SEM_NESTED if nested enter on a no nesting section. (Asserted.)
368	* @retval VERR_SEM_DESTROYED if RTCritSectDelete was called while waiting.
369	*
370	* @param pCritSect The critical section.
371	*/
372	static int pdmCritSectTryEnter(PPDMCRITSECT pCritSect, PCRTLOCKVALSRCPOS pSrcPos)
373	{
374	/*
375	* If the critical section has already been destroyed, then inform the caller.
376	*/
377	AssertMsgReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC,
378	("%p %RX32\n", pCritSect, pCritSect->s.Core.u32Magic),
379	VERR_SEM_DESTROYED);
380
381	/*
382	* See if we're lucky.
383	*/
384	/* NOP ... */
385	if (pCritSect->s.Core.fFlags & RTCRITSECT_FLAGS_NOP)
386	return VINF_SUCCESS;
387
388	RTNATIVETHREAD hNativeSelf = pdmCritSectGetNativeSelf(pCritSect);
389	/* ... not owned ... */
390	if (ASMAtomicCmpXchgS32(&pCritSect->s.Core.cLockers, 0, -1))
391	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
392
393	/* ... or nested. */
394	if (pCritSect->s.Core.NativeThreadOwner == hNativeSelf)
395	{
396	ASMAtomicIncS32(&pCritSect->s.Core.cLockers);
397	ASMAtomicIncS32(&pCritSect->s.Core.cNestings);
398	Assert(pCritSect->s.Core.cNestings > 1);
399	return VINF_SUCCESS;
400	}
401
402	/* no spinning */
403
404	/*
405	* Return busy.
406	*/
407	#ifdef IN_RING3
408	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionR3);
409	#else
410	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionRZLock);
411	#endif
412	LogFlow(("PDMCritSectTryEnter: locked\n"));
413	return VERR_SEM_BUSY;
414	}
415
416
417	/**
418	* Try enter a critical section.
419	*
420	* @retval VINF_SUCCESS on success.
421	* @retval VERR_SEM_BUSY if the critsect was owned.
422	* @retval VERR_SEM_NESTED if nested enter on a no nesting section. (Asserted.)
423	* @retval VERR_SEM_DESTROYED if RTCritSectDelete was called while waiting.
424	*
425	* @param pCritSect The critical section.
426	*/
427	VMMDECL(int) PDMCritSectTryEnter(PPDMCRITSECT pCritSect)
428	{
429	#ifndef PDMCRITSECT_STRICT
430	return pdmCritSectTryEnter(pCritSect, NULL);
431	#else
432	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
433	return pdmCritSectTryEnter(pCritSect, &SrcPos);
434	#endif
435	}
436
437
438	/**
439	* Try enter a critical section, with location information for debugging.
440	*
441	* @retval VINF_SUCCESS on success.
442	* @retval VERR_SEM_BUSY if the critsect was owned.
443	* @retval VERR_SEM_NESTED if nested enter on a no nesting section. (Asserted.)
444	* @retval VERR_SEM_DESTROYED if RTCritSectDelete was called while waiting.
445	*
446	* @param pCritSect The critical section.
447	* @param uId Some kind of locking location ID. Typically a
448	* return address up the stack. Optional (0).
449	* @param pszFile The file where the lock is being acquired from.
450	* Optional.
451	* @param iLine The line number in that file. Optional (0).
452	* @param pszFunction The function where the lock is being acquired
453	* from. Optional.
454	*/
455	VMMDECL(int) PDMCritSectTryEnterDebug(PPDMCRITSECT pCritSect, RTHCUINTPTR uId, RT_SRC_POS_DECL)
456	{
457	#ifdef PDMCRITSECT_STRICT
458	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
459	return pdmCritSectTryEnter(pCritSect, &SrcPos);
460	#else
461	return pdmCritSectTryEnter(pCritSect, NULL);
462	#endif
463	}
464
465
466	#ifdef IN_RING3
467	/**
468	* Enters a PDM critical section.
469	*
470	* @returns VINF_SUCCESS if entered successfully.
471	* @returns rcBusy when encountering a busy critical section in GC/R0.
472	* @returns VERR_SEM_DESTROYED if the critical section is dead.
473	*
474	* @param pCritSect The PDM critical section to enter.
475	* @param fCallRing3 Whether this is a VMMRZCallRing3()request.
476	*/
477	VMMR3DECL(int) PDMR3CritSectEnterEx(PPDMCRITSECT pCritSect, bool fCallRing3)
478	{
479	int rc = PDMCritSectEnter(pCritSect, VERR_INTERNAL_ERROR);
480	if ( rc == VINF_SUCCESS
481	&& fCallRing3
482	&& pCritSect->s.Core.pValidatorRec
483	&& pCritSect->s.Core.pValidatorRec->hThread != NIL_RTTHREAD)
484	RTLockValidatorRecExclReleaseOwnerUnchecked(pCritSect->s.Core.pValidatorRec);
485	return rc;
486	}
487	#endif /* IN_RING3 */
488
489
490	/**
491	* Leaves a critical section entered with PDMCritSectEnter().
492	*
493	* @returns Indication whether we really exited the critical section.
494	* @retval VINF_SUCCESS if we really exited.
495	* @retval VINF_SEM_NESTED if we only reduced the nesting count.
496	* @retval VERR_NOT_OWNER if you somehow ignore release assertions.
497	*
498	* @param pCritSect The PDM critical section to leave.
499	*/
500	VMMDECL(int) PDMCritSectLeave(PPDMCRITSECT pCritSect)
501	{
502	AssertMsg(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC, ("%p %RX32\n", pCritSect, pCritSect->s.Core.u32Magic));
503	Assert(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC);
504
505	/* Check for NOP sections before asserting ownership. */
506	if (pCritSect->s.Core.fFlags & RTCRITSECT_FLAGS_NOP)
507	return VINF_SUCCESS;
508
509	/*
510	* Always check that the caller is the owner (screw performance).
511	*/
512	RTNATIVETHREAD const hNativeSelf = pdmCritSectGetNativeSelf(pCritSect);
513	AssertReleaseMsgReturn(pCritSect->s.Core.NativeThreadOwner == hNativeSelf,
514	("%p %s: %p != %p; cLockers=%d cNestings=%d\n", pCritSect, R3STRING(pCritSect->s.pszName),
515	pCritSect->s.Core.NativeThreadOwner, hNativeSelf,
516	pCritSect->s.Core.cLockers, pCritSect->s.Core.cNestings),
517	VERR_NOT_OWNER);
518	Assert(pCritSect->s.Core.cNestings >= 1);
519
520	/*
521	* Nested leave.
522	*/
523	if (pCritSect->s.Core.cNestings > 1)
524	{
525	ASMAtomicDecS32(&pCritSect->s.Core.cNestings);
526	Assert(pCritSect->s.Core.cNestings >= 1);
527	ASMAtomicDecS32(&pCritSect->s.Core.cLockers);
528	Assert(pCritSect->s.Core.cLockers >= 0);
529	return VINF_SEM_NESTED;
530	}
531
532	#ifdef IN_RING0
533	# if 0 /** @todo Make SUPSemEventSignal interrupt safe (handle table++) and enable this for: defined(RT_OS_LINUX) \|\| defined(RT_OS_OS2) */
534	if (1) /* SUPSemEventSignal is safe */
535	# else
536	if (ASMIntAreEnabled())
537	# endif
538	#endif
539	#if defined(IN_RING3) \|\| defined(IN_RING0)
540	{
541	/*
542	* Leave for real.
543	*/
544	/* update members. */
545	# ifdef IN_RING3
546	RTSEMEVENT hEventToSignal = pCritSect->s.EventToSignal;
547	pCritSect->s.EventToSignal = NIL_RTSEMEVENT;
548	# if defined(PDMCRITSECT_STRICT)
549	if (pCritSect->s.Core.pValidatorRec->hThread != NIL_RTTHREAD)
550	RTLockValidatorRecExclReleaseOwnerUnchecked(pCritSect->s.Core.pValidatorRec);
551	# endif
552	Assert(!pCritSect->s.Core.pValidatorRec \|\| pCritSect->s.Core.pValidatorRec->hThread == NIL_RTTHREAD);
553	# endif
554	ASMAtomicAndU32(&pCritSect->s.Core.fFlags, ~PDMCRITSECT_FLAGS_PENDING_UNLOCK);
555	ASMAtomicWriteHandle(&pCritSect->s.Core.NativeThreadOwner, NIL_RTNATIVETHREAD);
556	ASMAtomicDecS32(&pCritSect->s.Core.cNestings);
557	Assert(pCritSect->s.Core.cNestings == 0);
558
559	/* stop and decrement lockers. */
560	STAM_PROFILE_ADV_STOP(&pCritSect->s.StatLocked, l);
561	ASMCompilerBarrier();
562	if (ASMAtomicDecS32(&pCritSect->s.Core.cLockers) >= 0)
563	{
564	/* Someone is waiting, wake up one of them. */
565	SUPSEMEVENT hEvent = (SUPSEMEVENT)pCritSect->s.Core.EventSem;
566	PSUPDRVSESSION pSession = pCritSect->s.CTX_SUFF(pVM)->pSession;
567	int rc = SUPSemEventSignal(pSession, hEvent);
568	AssertRC(rc);
569	}
570
571	# ifdef IN_RING3
572	/* Signal exit event. */
573	if (hEventToSignal != NIL_RTSEMEVENT)
574	{
575	LogBird(("Signalling %#x\n", hEventToSignal));
576	int rc = RTSemEventSignal(hEventToSignal);
577	AssertRC(rc);
578	}
579	# endif
580
581	# if defined(DEBUG_bird) && defined(IN_RING0)
582	VMMTrashVolatileXMMRegs();
583	# endif
584	}
585	#endif /* IN_RING3 \|\| IN_RING0 */
586	#ifdef IN_RING0
587	else
588	#endif
589	#if defined(IN_RING0) \|\| defined(IN_RC)
590	{
591	/*
592	* Try leave it.
593	*/
594	if (pCritSect->s.Core.cLockers == 0)
595	{
596	ASMAtomicWriteS32(&pCritSect->s.Core.cNestings, 0);
597	RTNATIVETHREAD hNativeThread = pCritSect->s.Core.NativeThreadOwner;
598	ASMAtomicAndU32(&pCritSect->s.Core.fFlags, ~PDMCRITSECT_FLAGS_PENDING_UNLOCK);
599	STAM_PROFILE_ADV_STOP(&pCritSect->s.StatLocked, l);
600
601	ASMAtomicWriteHandle(&pCritSect->s.Core.NativeThreadOwner, NIL_RTNATIVETHREAD);
602	if (ASMAtomicCmpXchgS32(&pCritSect->s.Core.cLockers, -1, 0))
603	return VINF_SUCCESS;
604
605	/* darn, someone raced in on us. */
606	ASMAtomicWriteHandle(&pCritSect->s.Core.NativeThreadOwner, hNativeThread);
607	STAM_PROFILE_ADV_START(&pCritSect->s.StatLocked, l);
608	Assert(pCritSect->s.Core.cNestings == 0);
609	ASMAtomicWriteS32(&pCritSect->s.Core.cNestings, 1);
610	}
611	ASMAtomicOrU32(&pCritSect->s.Core.fFlags, PDMCRITSECT_FLAGS_PENDING_UNLOCK);
612
613	/*
614	* Queue the request.
615	*/
616	PVM pVM = pCritSect->s.CTX_SUFF(pVM); AssertPtr(pVM);
617	PVMCPU pVCpu = VMMGetCpu(pVM); AssertPtr(pVCpu);
618	uint32_t i = pVCpu->pdm.s.cQueuedCritSectLeaves++;
619	LogFlow(("PDMCritSectLeave: [%d]=%p => R3\n", i, pCritSect));
620	AssertFatal(i < RT_ELEMENTS(pVCpu->pdm.s.apQueuedCritSectsLeaves));
621	pVCpu->pdm.s.apQueuedCritSectsLeaves[i] = MMHyperCCToR3(pVM, pCritSect);
622	VMCPU_FF_SET(pVCpu, VMCPU_FF_PDM_CRITSECT);
623	VMCPU_FF_SET(pVCpu, VMCPU_FF_TO_R3);
624	STAM_REL_COUNTER_INC(&pVM->pdm.s.StatQueuedCritSectLeaves);
625	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionRZUnlock);
626	}
627	#endif /* IN_RING0 \|\| IN_RC */
628
629	return VINF_SUCCESS;
630	}
631
632
633	#if defined(IN_RING3) \|\| defined(IN_RING0)
634	/**
635	* Process the critical sections queued for ring-3 'leave'.
636	*
637	* @param pVCpu The VMCPU handle.
638	*/
639	VMMDECL(void) PDMCritSectFF(PVMCPU pVCpu)
640	{
641	Assert(pVCpu->pdm.s.cQueuedCritSectLeaves > 0);
642
643	const RTUINT c = pVCpu->pdm.s.cQueuedCritSectLeaves;
644	for (RTUINT i = 0; i < c; i++)
645	{
646	# ifdef IN_RING3
647	PPDMCRITSECT pCritSect = pVCpu->pdm.s.apQueuedCritSectsLeaves[i];
648	# else
649	PPDMCRITSECT pCritSect = (PPDMCRITSECT)MMHyperR3ToCC(pVCpu->CTX_SUFF(pVM), pVCpu->pdm.s.apQueuedCritSectsLeaves[i]);
650	# endif
651
652	PDMCritSectLeave(pCritSect);
653	LogFlow(("PDMR3CritSectFF: %p\n", pCritSect));
654	}
655
656	pVCpu->pdm.s.cQueuedCritSectLeaves = 0;
657	VMCPU_FF_CLEAR(pVCpu, VMCPU_FF_PDM_CRITSECT);
658	}
659	#endif /* IN_RING3 \|\| IN_RING0 */
660
661
662	/**
663	* Checks the caller is the owner of the critical section.
664	*
665	* @returns true if owner.
666	* @returns false if not owner.
667	* @param pCritSect The critical section.
668	*/
669	VMMDECL(bool) PDMCritSectIsOwner(PCPDMCRITSECT pCritSect)
670	{
671	#ifdef IN_RING3
672	return RTCritSectIsOwner(&pCritSect->s.Core);
673	#else
674	PVM pVM = pCritSect->s.CTX_SUFF(pVM); AssertPtr(pVM);
675	PVMCPU pVCpu = VMMGetCpu(pVM); AssertPtr(pVCpu);
676	if (pCritSect->s.Core.NativeThreadOwner != pVCpu->hNativeThread)
677	return false;
678	return (pCritSect->s.Core.fFlags & PDMCRITSECT_FLAGS_PENDING_UNLOCK) == 0
679	\|\| pCritSect->s.Core.cNestings > 1;
680	#endif
681	}
682
683
684	/**
685	* Checks the specified VCPU is the owner of the critical section.
686	*
687	* @returns true if owner.
688	* @returns false if not owner.
689	* @param pCritSect The critical section.
690	* @param pVCpu The virtual CPU handle.
691	*/
692	VMMDECL(bool) PDMCritSectIsOwnerEx(PCPDMCRITSECT pCritSect, PVMCPU pVCpu)
693	{
694	#ifdef IN_RING3
695	NOREF(pVCpu);
696	return RTCritSectIsOwner(&pCritSect->s.Core);
697	#else
698	Assert(&pVCpu->CTX_SUFF(pVM)->aCpus[pVCpu->idCpu] == pVCpu);
699	if (pCritSect->s.Core.NativeThreadOwner != pVCpu->hNativeThread)
700	return false;
701	return (pCritSect->s.Core.fFlags & PDMCRITSECT_FLAGS_PENDING_UNLOCK) == 0
702	\|\| pCritSect->s.Core.cNestings > 1;
703	#endif
704	}
705
706
707	/**
708	* Checks if anyone is waiting on the critical section we own.
709	*
710	* @returns true if someone is waiting.
711	* @returns false if no one is waiting.
712	* @param pCritSect The critical section.
713	*/
714	VMMDECL(bool) PDMCritSectHasWaiters(PCPDMCRITSECT pCritSect)
715	{
716	AssertReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC, false);
717	Assert(pCritSect->s.Core.NativeThreadOwner == pdmCritSectGetNativeSelf(pCritSect));
718	return pCritSect->s.Core.cLockers >= pCritSect->s.Core.cNestings;
719	}
720
721
722	/**
723	* Checks if a critical section is initialized or not.
724	*
725	* @returns true if initialized.
726	* @returns false if not initialized.
727	* @param pCritSect The critical section.
728	*/
729	VMMDECL(bool) PDMCritSectIsInitialized(PCPDMCRITSECT pCritSect)
730	{
731	return RTCritSectIsInitialized(&pCritSect->s.Core);
732	}
733
734
735	/**
736	* Gets the recursion depth.
737	*
738	* @returns The recursion depth.
739	* @param pCritSect The critical section.
740	*/
741	VMMDECL(uint32_t) PDMCritSectGetRecursion(PCPDMCRITSECT pCritSect)
742	{
743	return RTCritSectGetRecursion(&pCritSect->s.Core);
744	}

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source: vbox/trunk/src/VBox/VMM/VMMAll/PDMAllCritSect.cpp@ 39012

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