PDMAllCritSect.cpp@ 55889

Last change on this file since 55889 was 50000, checked in by vboxsync, 11 years ago
pdmR3R0CritSectEnterContended: That worked but wasn't entirely correct, so next attempt.
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1	/* $Id: PDMAllCritSect.cpp 50000 2013-12-24 21:03:10Z vboxsync $ */
2	/** @file
3	* PDM - Write-Only Critical Section, All Contexts.
4	*/
5
6	/*
7	* Copyright (C) 2006-2013 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/hm.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	# else
102	NOREF(pSrcPos);
103	# endif
104
105	STAM_PROFILE_ADV_START(&pCritSect->s.StatLocked, l);
106	return VINF_SUCCESS;
107	}
108
109
110	#if defined(IN_RING3) \|\| defined(IN_RING0)
111	/**
112	* Deals with the contended case in ring-3 and ring-0.
113	*
114	* @retval VINF_SUCCESS on success.
115	* @retval VERR_SEM_DESTROYED if destroyed.
116	*
117	* @param pCritSect The critsect.
118	* @param hNativeSelf The native thread handle.
119	*/
120	static int pdmR3R0CritSectEnterContended(PPDMCRITSECT pCritSect, RTNATIVETHREAD hNativeSelf, PCRTLOCKVALSRCPOS pSrcPos)
121	{
122	/*
123	* Start waiting.
124	*/
125	if (ASMAtomicIncS32(&pCritSect->s.Core.cLockers) == 0)
126	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
127	# ifdef IN_RING3
128	STAM_COUNTER_INC(&pCritSect->s.StatContentionR3);
129	# else
130	STAM_COUNTER_INC(&pCritSect->s.StatContentionRZLock);
131	# endif
132
133	/*
134	* The wait loop.
135	*/
136	PSUPDRVSESSION pSession = pCritSect->s.CTX_SUFF(pVM)->pSession;
137	SUPSEMEVENT hEvent = (SUPSEMEVENT)pCritSect->s.Core.EventSem;
138	# ifdef IN_RING3
139	# ifdef PDMCRITSECT_STRICT
140	RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
141	int rc2 = RTLockValidatorRecExclCheckOrder(pCritSect->s.Core.pValidatorRec, hThreadSelf, pSrcPos, RT_INDEFINITE_WAIT);
142	if (RT_FAILURE(rc2))
143	return rc2;
144	# else
145	RTTHREAD hThreadSelf = RTThreadSelf();
146	# endif
147	# endif
148	for (;;)
149	{
150	/*
151	* Do the wait.
152	*
153	* In ring-3 this gets cluttered by lock validation and thread state
154	* maintainence.
155	*
156	* In ring-0 we have to deal with the possibility that the thread has
157	* been signalled and the interruptible wait function returning
158	* immediately. In that case we do normal R0/RC rcBusy handling.
159	*/
160	# ifdef IN_RING3
161	# ifdef PDMCRITSECT_STRICT
162	int rc9 = RTLockValidatorRecExclCheckBlocking(pCritSect->s.Core.pValidatorRec, hThreadSelf, pSrcPos,
163	!(pCritSect->s.Core.fFlags & RTCRITSECT_FLAGS_NO_NESTING),
164	RT_INDEFINITE_WAIT, RTTHREADSTATE_CRITSECT, true);
165	if (RT_FAILURE(rc9))
166	return rc9;
167	# else
168	RTThreadBlocking(hThreadSelf, RTTHREADSTATE_CRITSECT, true);
169	# endif
170	int rc = SUPSemEventWaitNoResume(pSession, hEvent, RT_INDEFINITE_WAIT);
171	RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_CRITSECT);
172	# else /* IN_RING0 */
173	int rc = SUPSemEventWaitNoResume(pSession, hEvent, RT_INDEFINITE_WAIT);
174	# endif /* IN_RING0 */
175
176	/*
177	* Deal with the return code and critsect destruction.
178	*/
179	if (RT_UNLIKELY(pCritSect->s.Core.u32Magic != RTCRITSECT_MAGIC))
180	return VERR_SEM_DESTROYED;
181	if (rc == VINF_SUCCESS)
182	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
183	AssertMsg(rc == VERR_INTERRUPTED, ("rc=%Rrc\n", rc));
184
185	# ifdef IN_RING0
186	/* Something is pending (signal, APC, debugger, whatever), just go back
187	to ring-3 so the kernel can deal with it when leaving kernel context.
188
189	Note! We've incremented cLockers already and cannot safely decrement
190	it without creating a race with PDMCritSectLeave, resulting in
191	spurious wakeups. */
192	PVM pVM = pCritSect->s.CTX_SUFF(pVM); AssertPtr(pVM);
193	PVMCPU pVCpu = VMMGetCpu(pVM); AssertPtr(pVCpu);
194	rc = VMMRZCallRing3(pVM, pVCpu, VMMCALLRING3_VM_R0_PREEMPT, NULL);
195	AssertRC(rc);
196	# endif
197	}
198	/* won't get here */
199	}
200	#endif /* IN_RING3 \|\| IN_RING0 */
201
202
203	/**
204	* Common worker for the debug and normal APIs.
205	*
206	* @returns VINF_SUCCESS if entered successfully.
207	* @returns rcBusy when encountering a busy critical section in GC/R0.
208	* @retval VERR_SEM_DESTROYED if the critical section is delete before or
209	* during the operation.
210	*
211	* @param pCritSect The PDM critical section to enter.
212	* @param rcBusy The status code to return when we're in GC or R0
213	* and the section is busy.
214	*/
215	DECL_FORCE_INLINE(int) pdmCritSectEnter(PPDMCRITSECT pCritSect, int rcBusy, PCRTLOCKVALSRCPOS pSrcPos)
216	{
217	Assert(pCritSect->s.Core.cNestings < 8); /* useful to catch incorrect locking */
218	Assert(pCritSect->s.Core.cNestings >= 0);
219
220	/*
221	* If the critical section has already been destroyed, then inform the caller.
222	*/
223	AssertMsgReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC,
224	("%p %RX32\n", pCritSect, pCritSect->s.Core.u32Magic),
225	VERR_SEM_DESTROYED);
226
227	/*
228	* See if we're lucky.
229	*/
230	/* NOP ... */
231	if (pCritSect->s.Core.fFlags & RTCRITSECT_FLAGS_NOP)
232	return VINF_SUCCESS;
233
234	RTNATIVETHREAD hNativeSelf = pdmCritSectGetNativeSelf(pCritSect);
235	/* ... not owned ... */
236	if (ASMAtomicCmpXchgS32(&pCritSect->s.Core.cLockers, 0, -1))
237	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
238
239	/* ... or nested. */
240	if (pCritSect->s.Core.NativeThreadOwner == hNativeSelf)
241	{
242	ASMAtomicIncS32(&pCritSect->s.Core.cLockers);
243	ASMAtomicIncS32(&pCritSect->s.Core.cNestings);
244	Assert(pCritSect->s.Core.cNestings > 1);
245	return VINF_SUCCESS;
246	}
247
248	/*
249	* Spin for a bit without incrementing the counter.
250	*/
251	/** @todo Move this to cfgm variables since it doesn't make sense to spin on UNI
252	* cpu systems. */
253	int32_t cSpinsLeft = CTX_SUFF(PDMCRITSECT_SPIN_COUNT_);
254	while (cSpinsLeft-- > 0)
255	{
256	if (ASMAtomicCmpXchgS32(&pCritSect->s.Core.cLockers, 0, -1))
257	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
258	ASMNopPause();
259	/** @todo Should use monitor/mwait on e.g. &cLockers here, possibly with a
260	cli'ed pendingpreemption check up front using sti w/ instruction fusing
261	for avoiding races. Hmm ... This is assuming the other party is actually
262	executing code on another CPU ... which we could keep track of if we
263	wanted. */
264	}
265
266	#ifdef IN_RING3
267	/*
268	* Take the slow path.
269	*/
270	NOREF(rcBusy);
271	return pdmR3R0CritSectEnterContended(pCritSect, hNativeSelf, pSrcPos);
272
273	#else
274	# ifdef IN_RING0
275	/** @todo If preemption is disabled it means we're in VT-x/AMD-V context
276	* and would be better off switching out of that while waiting for
277	* the lock. Several of the locks jumps back to ring-3 just to
278	* get the lock, the ring-3 code will then call the kernel to do
279	* the lock wait and when the call return it will call ring-0
280	* again and resume via in setjmp style. Not very efficient. */
281	# if 0
282	if (ASMIntAreEnabled()) /** @todo this can be handled as well by changing
283	* callers not prepared for longjmp/blocking to
284	* use PDMCritSectTryEnter. */
285	{
286	/*
287	* Leave HM context while waiting if necessary.
288	*/
289	int rc;
290	if (RTThreadPreemptIsEnabled(NIL_RTTHREAD))
291	{
292	STAM_REL_COUNTER_ADD(&pCritSect->s.StatContentionRZLock, 1000000);
293	rc = pdmR3R0CritSectEnterContended(pCritSect, hNativeSelf, pSrcPos);
294	}
295	else
296	{
297	STAM_REL_COUNTER_ADD(&pCritSect->s.StatContentionRZLock, 1000000000);
298	PVM pVM = pCritSect->s.CTX_SUFF(pVM);
299	PVMCPU pVCpu = VMMGetCpu(pVM);
300	HMR0Leave(pVM, pVCpu);
301	RTThreadPreemptRestore(NIL_RTTHREAD, XXX);
302
303	rc = pdmR3R0CritSectEnterContended(pCritSect, hNativeSelf, pSrcPos);
304
305	RTThreadPreemptDisable(NIL_RTTHREAD, XXX);
306	HMR0Enter(pVM, pVCpu);
307	}
308	return rc;
309	}
310	# else
311	/*
312	* We preemption hasn't been disabled, we can block here in ring-0.
313	*/
314	if ( RTThreadPreemptIsEnabled(NIL_RTTHREAD)
315	&& ASMIntAreEnabled())
316	return pdmR3R0CritSectEnterContended(pCritSect, hNativeSelf, pSrcPos);
317	# endif
318	#endif /* IN_RING0 */
319
320	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionRZLock);
321
322	/*
323	* Call ring-3 to acquire the critical section?
324	*/
325	if (rcBusy == VINF_SUCCESS)
326	{
327	PVM pVM = pCritSect->s.CTX_SUFF(pVM); AssertPtr(pVM);
328	PVMCPU pVCpu = VMMGetCpu(pVM); AssertPtr(pVCpu);
329	return VMMRZCallRing3(pVM, pVCpu, VMMCALLRING3_PDM_CRIT_SECT_ENTER, MMHyperCCToR3(pVM, pCritSect));
330	}
331
332	/*
333	* Return busy.
334	*/
335	LogFlow(("PDMCritSectEnter: locked => R3 (%Rrc)\n", rcBusy));
336	return rcBusy;
337	#endif /* !IN_RING3 */
338	}
339
340
341	/**
342	* Enters a PDM critical section.
343	*
344	* @returns VINF_SUCCESS if entered successfully.
345	* @returns rcBusy when encountering a busy critical section in RC/R0.
346	* @retval VERR_SEM_DESTROYED if the critical section is delete before or
347	* during the operation.
348	*
349	* @param pCritSect The PDM critical section to enter.
350	* @param rcBusy The status code to return when we're in RC or R0
351	* and the section is busy. Pass VINF_SUCCESS to
352	* acquired the critical section thru a ring-3
353	* call if necessary.
354	*/
355	VMMDECL(int) PDMCritSectEnter(PPDMCRITSECT pCritSect, int rcBusy)
356	{
357	#ifndef PDMCRITSECT_STRICT
358	return pdmCritSectEnter(pCritSect, rcBusy, NULL);
359	#else
360	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
361	return pdmCritSectEnter(pCritSect, rcBusy, &SrcPos);
362	#endif
363	}
364
365
366	/**
367	* Enters a PDM critical section, with location information for debugging.
368	*
369	* @returns VINF_SUCCESS if entered successfully.
370	* @returns rcBusy when encountering a busy critical section in RC/R0.
371	* @retval VERR_SEM_DESTROYED if the critical section is delete before or
372	* during the operation.
373	*
374	* @param pCritSect The PDM critical section to enter.
375	* @param rcBusy The status code to return when we're in RC or R0
376	* and the section is busy. Pass VINF_SUCCESS to
377	* acquired the critical section thru a ring-3
378	* call if necessary.
379	* @param uId Some kind of locking location ID. Typically a
380	* return address up the stack. Optional (0).
381	* @param pszFile The file where the lock is being acquired from.
382	* Optional.
383	* @param iLine The line number in that file. Optional (0).
384	* @param pszFunction The function where the lock is being acquired
385	* from. Optional.
386	*/
387	VMMDECL(int) PDMCritSectEnterDebug(PPDMCRITSECT pCritSect, int rcBusy, RTHCUINTPTR uId, RT_SRC_POS_DECL)
388	{
389	#ifdef PDMCRITSECT_STRICT
390	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
391	return pdmCritSectEnter(pCritSect, rcBusy, &SrcPos);
392	#else
393	NOREF(uId); RT_SRC_POS_NOREF();
394	return pdmCritSectEnter(pCritSect, rcBusy, NULL);
395	#endif
396	}
397
398
399	/**
400	* Common worker for the debug and normal APIs.
401	*
402	* @retval VINF_SUCCESS on success.
403	* @retval VERR_SEM_BUSY if the critsect was owned.
404	* @retval VERR_SEM_NESTED if nested enter on a no nesting section. (Asserted.)
405	* @retval VERR_SEM_DESTROYED if the critical section is delete before or
406	* during the operation.
407	*
408	* @param pCritSect The critical section.
409	*/
410	static int pdmCritSectTryEnter(PPDMCRITSECT pCritSect, PCRTLOCKVALSRCPOS pSrcPos)
411	{
412	/*
413	* If the critical section has already been destroyed, then inform the caller.
414	*/
415	AssertMsgReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC,
416	("%p %RX32\n", pCritSect, pCritSect->s.Core.u32Magic),
417	VERR_SEM_DESTROYED);
418
419	/*
420	* See if we're lucky.
421	*/
422	/* NOP ... */
423	if (pCritSect->s.Core.fFlags & RTCRITSECT_FLAGS_NOP)
424	return VINF_SUCCESS;
425
426	RTNATIVETHREAD hNativeSelf = pdmCritSectGetNativeSelf(pCritSect);
427	/* ... not owned ... */
428	if (ASMAtomicCmpXchgS32(&pCritSect->s.Core.cLockers, 0, -1))
429	return pdmCritSectEnterFirst(pCritSect, hNativeSelf, pSrcPos);
430
431	/* ... or nested. */
432	if (pCritSect->s.Core.NativeThreadOwner == hNativeSelf)
433	{
434	ASMAtomicIncS32(&pCritSect->s.Core.cLockers);
435	ASMAtomicIncS32(&pCritSect->s.Core.cNestings);
436	Assert(pCritSect->s.Core.cNestings > 1);
437	return VINF_SUCCESS;
438	}
439
440	/* no spinning */
441
442	/*
443	* Return busy.
444	*/
445	#ifdef IN_RING3
446	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionR3);
447	#else
448	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionRZLock);
449	#endif
450	LogFlow(("PDMCritSectTryEnter: locked\n"));
451	return VERR_SEM_BUSY;
452	}
453
454
455	/**
456	* Try enter a critical section.
457	*
458	* @retval VINF_SUCCESS on success.
459	* @retval VERR_SEM_BUSY if the critsect was owned.
460	* @retval VERR_SEM_NESTED if nested enter on a no nesting section. (Asserted.)
461	* @retval VERR_SEM_DESTROYED if the critical section is delete before or
462	* during the operation.
463	*
464	* @param pCritSect The critical section.
465	*/
466	VMMDECL(int) PDMCritSectTryEnter(PPDMCRITSECT pCritSect)
467	{
468	#ifndef PDMCRITSECT_STRICT
469	return pdmCritSectTryEnter(pCritSect, NULL);
470	#else
471	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
472	return pdmCritSectTryEnter(pCritSect, &SrcPos);
473	#endif
474	}
475
476
477	/**
478	* Try enter a critical section, with location information for debugging.
479	*
480	* @retval VINF_SUCCESS on success.
481	* @retval VERR_SEM_BUSY if the critsect was owned.
482	* @retval VERR_SEM_NESTED if nested enter on a no nesting section. (Asserted.)
483	* @retval VERR_SEM_DESTROYED if the critical section is delete before or
484	* during the operation.
485	*
486	* @param pCritSect The critical section.
487	* @param uId Some kind of locking location ID. Typically a
488	* return address up the stack. Optional (0).
489	* @param pszFile The file where the lock is being acquired from.
490	* Optional.
491	* @param iLine The line number in that file. Optional (0).
492	* @param pszFunction The function where the lock is being acquired
493	* from. Optional.
494	*/
495	VMMDECL(int) PDMCritSectTryEnterDebug(PPDMCRITSECT pCritSect, RTHCUINTPTR uId, RT_SRC_POS_DECL)
496	{
497	#ifdef PDMCRITSECT_STRICT
498	RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
499	return pdmCritSectTryEnter(pCritSect, &SrcPos);
500	#else
501	NOREF(uId); RT_SRC_POS_NOREF();
502	return pdmCritSectTryEnter(pCritSect, NULL);
503	#endif
504	}
505
506
507	#ifdef IN_RING3
508	/**
509	* Enters a PDM critical section.
510	*
511	* @returns VINF_SUCCESS if entered successfully.
512	* @returns rcBusy when encountering a busy critical section in GC/R0.
513	* @retval VERR_SEM_DESTROYED if the critical section is delete before or
514	* during the operation.
515	*
516	* @param pCritSect The PDM critical section to enter.
517	* @param fCallRing3 Whether this is a VMMRZCallRing3()request.
518	*/
519	VMMR3DECL(int) PDMR3CritSectEnterEx(PPDMCRITSECT pCritSect, bool fCallRing3)
520	{
521	int rc = PDMCritSectEnter(pCritSect, VERR_IGNORED);
522	if ( rc == VINF_SUCCESS
523	&& fCallRing3
524	&& pCritSect->s.Core.pValidatorRec
525	&& pCritSect->s.Core.pValidatorRec->hThread != NIL_RTTHREAD)
526	RTLockValidatorRecExclReleaseOwnerUnchecked(pCritSect->s.Core.pValidatorRec);
527	return rc;
528	}
529	#endif /* IN_RING3 */
530
531
532	/**
533	* Leaves a critical section entered with PDMCritSectEnter().
534	*
535	* @returns Indication whether we really exited the critical section.
536	* @retval VINF_SUCCESS if we really exited.
537	* @retval VINF_SEM_NESTED if we only reduced the nesting count.
538	* @retval VERR_NOT_OWNER if you somehow ignore release assertions.
539	*
540	* @param pCritSect The PDM critical section to leave.
541	*/
542	VMMDECL(int) PDMCritSectLeave(PPDMCRITSECT pCritSect)
543	{
544	AssertMsg(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC, ("%p %RX32\n", pCritSect, pCritSect->s.Core.u32Magic));
545	Assert(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC);
546
547	/* Check for NOP sections before asserting ownership. */
548	if (pCritSect->s.Core.fFlags & RTCRITSECT_FLAGS_NOP)
549	return VINF_SUCCESS;
550
551	/*
552	* Always check that the caller is the owner (screw performance).
553	*/
554	RTNATIVETHREAD const hNativeSelf = pdmCritSectGetNativeSelf(pCritSect);
555	AssertReleaseMsgReturn(pCritSect->s.Core.NativeThreadOwner == hNativeSelf,
556	("%p %s: %p != %p; cLockers=%d cNestings=%d\n", pCritSect, R3STRING(pCritSect->s.pszName),
557	pCritSect->s.Core.NativeThreadOwner, hNativeSelf,
558	pCritSect->s.Core.cLockers, pCritSect->s.Core.cNestings),
559	VERR_NOT_OWNER);
560	Assert(pCritSect->s.Core.cNestings >= 1);
561
562	/*
563	* Nested leave.
564	*/
565	if (pCritSect->s.Core.cNestings > 1)
566	{
567	ASMAtomicDecS32(&pCritSect->s.Core.cNestings);
568	Assert(pCritSect->s.Core.cNestings >= 1);
569	ASMAtomicDecS32(&pCritSect->s.Core.cLockers);
570	Assert(pCritSect->s.Core.cLockers >= 0);
571	return VINF_SEM_NESTED;
572	}
573
574	#ifdef IN_RING0
575	# if 0 /** @todo Make SUPSemEventSignal interrupt safe (handle table++) and enable this for: defined(RT_OS_LINUX) \|\| defined(RT_OS_OS2) */
576	if (1) /* SUPSemEventSignal is safe */
577	# else
578	if (ASMIntAreEnabled())
579	# endif
580	#endif
581	#if defined(IN_RING3) \|\| defined(IN_RING0)
582	{
583	/*
584	* Leave for real.
585	*/
586	/* update members. */
587	# ifdef IN_RING3
588	RTSEMEVENT hEventToSignal = pCritSect->s.EventToSignal;
589	pCritSect->s.EventToSignal = NIL_RTSEMEVENT;
590	# if defined(PDMCRITSECT_STRICT)
591	if (pCritSect->s.Core.pValidatorRec->hThread != NIL_RTTHREAD)
592	RTLockValidatorRecExclReleaseOwnerUnchecked(pCritSect->s.Core.pValidatorRec);
593	# endif
594	Assert(!pCritSect->s.Core.pValidatorRec \|\| pCritSect->s.Core.pValidatorRec->hThread == NIL_RTTHREAD);
595	# endif
596	ASMAtomicAndU32(&pCritSect->s.Core.fFlags, ~PDMCRITSECT_FLAGS_PENDING_UNLOCK);
597	ASMAtomicWriteHandle(&pCritSect->s.Core.NativeThreadOwner, NIL_RTNATIVETHREAD);
598	ASMAtomicDecS32(&pCritSect->s.Core.cNestings);
599	Assert(pCritSect->s.Core.cNestings == 0);
600
601	/* stop and decrement lockers. */
602	STAM_PROFILE_ADV_STOP(&pCritSect->s.StatLocked, l);
603	ASMCompilerBarrier();
604	if (ASMAtomicDecS32(&pCritSect->s.Core.cLockers) >= 0)
605	{
606	/* Someone is waiting, wake up one of them. */
607	SUPSEMEVENT hEvent = (SUPSEMEVENT)pCritSect->s.Core.EventSem;
608	PSUPDRVSESSION pSession = pCritSect->s.CTX_SUFF(pVM)->pSession;
609	int rc = SUPSemEventSignal(pSession, hEvent);
610	AssertRC(rc);
611	}
612
613	# ifdef IN_RING3
614	/* Signal exit event. */
615	if (hEventToSignal != NIL_RTSEMEVENT)
616	{
617	LogBird(("Signalling %#x\n", hEventToSignal));
618	int rc = RTSemEventSignal(hEventToSignal);
619	AssertRC(rc);
620	}
621	# endif
622
623	# if defined(DEBUG_bird) && defined(IN_RING0)
624	VMMTrashVolatileXMMRegs();
625	# endif
626	}
627	#endif /* IN_RING3 \|\| IN_RING0 */
628	#ifdef IN_RING0
629	else
630	#endif
631	#if defined(IN_RING0) \|\| defined(IN_RC)
632	{
633	/*
634	* Try leave it.
635	*/
636	if (pCritSect->s.Core.cLockers == 0)
637	{
638	ASMAtomicWriteS32(&pCritSect->s.Core.cNestings, 0);
639	RTNATIVETHREAD hNativeThread = pCritSect->s.Core.NativeThreadOwner;
640	ASMAtomicAndU32(&pCritSect->s.Core.fFlags, ~PDMCRITSECT_FLAGS_PENDING_UNLOCK);
641	STAM_PROFILE_ADV_STOP(&pCritSect->s.StatLocked, l);
642
643	ASMAtomicWriteHandle(&pCritSect->s.Core.NativeThreadOwner, NIL_RTNATIVETHREAD);
644	if (ASMAtomicCmpXchgS32(&pCritSect->s.Core.cLockers, -1, 0))
645	return VINF_SUCCESS;
646
647	/* darn, someone raced in on us. */
648	ASMAtomicWriteHandle(&pCritSect->s.Core.NativeThreadOwner, hNativeThread);
649	STAM_PROFILE_ADV_START(&pCritSect->s.StatLocked, l);
650	Assert(pCritSect->s.Core.cNestings == 0);
651	ASMAtomicWriteS32(&pCritSect->s.Core.cNestings, 1);
652	}
653	ASMAtomicOrU32(&pCritSect->s.Core.fFlags, PDMCRITSECT_FLAGS_PENDING_UNLOCK);
654
655	/*
656	* Queue the request.
657	*/
658	PVM pVM = pCritSect->s.CTX_SUFF(pVM); AssertPtr(pVM);
659	PVMCPU pVCpu = VMMGetCpu(pVM); AssertPtr(pVCpu);
660	uint32_t i = pVCpu->pdm.s.cQueuedCritSectLeaves++;
661	LogFlow(("PDMCritSectLeave: [%d]=%p => R3\n", i, pCritSect));
662	AssertFatal(i < RT_ELEMENTS(pVCpu->pdm.s.apQueuedCritSectLeaves));
663	pVCpu->pdm.s.apQueuedCritSectLeaves[i] = MMHyperCCToR3(pVM, pCritSect);
664	VMCPU_FF_SET(pVCpu, VMCPU_FF_PDM_CRITSECT);
665	VMCPU_FF_SET(pVCpu, VMCPU_FF_TO_R3);
666	STAM_REL_COUNTER_INC(&pVM->pdm.s.StatQueuedCritSectLeaves);
667	STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionRZUnlock);
668	}
669	#endif /* IN_RING0 \|\| IN_RC */
670
671	return VINF_SUCCESS;
672	}
673
674
675	/**
676	* Checks the caller is the owner of the critical section.
677	*
678	* @returns true if owner.
679	* @returns false if not owner.
680	* @param pCritSect The critical section.
681	*/
682	VMMDECL(bool) PDMCritSectIsOwner(PCPDMCRITSECT pCritSect)
683	{
684	#ifdef IN_RING3
685	return RTCritSectIsOwner(&pCritSect->s.Core);
686	#else
687	PVM pVM = pCritSect->s.CTX_SUFF(pVM); AssertPtr(pVM);
688	PVMCPU pVCpu = VMMGetCpu(pVM); AssertPtr(pVCpu);
689	if (pCritSect->s.Core.NativeThreadOwner != pVCpu->hNativeThread)
690	return false;
691	return (pCritSect->s.Core.fFlags & PDMCRITSECT_FLAGS_PENDING_UNLOCK) == 0
692	\|\| pCritSect->s.Core.cNestings > 1;
693	#endif
694	}
695
696
697	/**
698	* Checks the specified VCPU is the owner of the critical section.
699	*
700	* @returns true if owner.
701	* @returns false if not owner.
702	* @param pCritSect The critical section.
703	* @param pVCpu Pointer to the VMCPU.
704	*/
705	VMMDECL(bool) PDMCritSectIsOwnerEx(PCPDMCRITSECT pCritSect, PVMCPU pVCpu)
706	{
707	#ifdef IN_RING3
708	NOREF(pVCpu);
709	return RTCritSectIsOwner(&pCritSect->s.Core);
710	#else
711	Assert(&pVCpu->CTX_SUFF(pVM)->aCpus[pVCpu->idCpu] == pVCpu);
712	if (pCritSect->s.Core.NativeThreadOwner != pVCpu->hNativeThread)
713	return false;
714	return (pCritSect->s.Core.fFlags & PDMCRITSECT_FLAGS_PENDING_UNLOCK) == 0
715	\|\| pCritSect->s.Core.cNestings > 1;
716	#endif
717	}
718
719
720	/**
721	* Checks if anyone is waiting on the critical section we own.
722	*
723	* @returns true if someone is waiting.
724	* @returns false if no one is waiting.
725	* @param pCritSect The critical section.
726	*/
727	VMMDECL(bool) PDMCritSectHasWaiters(PCPDMCRITSECT pCritSect)
728	{
729	AssertReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC, false);
730	Assert(pCritSect->s.Core.NativeThreadOwner == pdmCritSectGetNativeSelf(pCritSect));
731	return pCritSect->s.Core.cLockers >= pCritSect->s.Core.cNestings;
732	}
733
734
735	/**
736	* Checks if a critical section is initialized or not.
737	*
738	* @returns true if initialized.
739	* @returns false if not initialized.
740	* @param pCritSect The critical section.
741	*/
742	VMMDECL(bool) PDMCritSectIsInitialized(PCPDMCRITSECT pCritSect)
743	{
744	return RTCritSectIsInitialized(&pCritSect->s.Core);
745	}
746
747
748	/**
749	* Gets the recursion depth.
750	*
751	* @returns The recursion depth.
752	* @param pCritSect The critical section.
753	*/
754	VMMDECL(uint32_t) PDMCritSectGetRecursion(PCPDMCRITSECT pCritSect)
755	{
756	return RTCritSectGetRecursion(&pCritSect->s.Core);
757	}
758

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source: vbox/trunk/src/VBox/VMM/VMMAll/PDMAllCritSect.cpp@ 55889

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