/* $Id: PDMCritSect.cpp 23350 2009-09-26 12:00:07Z vboxsync $ */ /** @file * PDM - Critical Sections, Ring-3. */ /* * Copyright (C) 2006-2009 Sun Microsystems, Inc. * * This file is part of VirtualBox Open Source Edition (OSE), as * available from http://www.virtualbox.org. This file is free software; * you can redistribute it and/or modify it under the terms of the GNU * General Public License (GPL) as published by the Free Software * Foundation, in version 2 as it comes in the "COPYING" file of the * VirtualBox OSE distribution. VirtualBox OSE is distributed in the * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind. * * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa * Clara, CA 95054 USA or visit http://www.sun.com if you need * additional information or have any questions. */ /******************************************************************************* * Header Files * *******************************************************************************/ #define LOG_GROUP LOG_GROUP_PDM//_CRITSECT #include "PDMInternal.h" #include #include #include #include #include #include #include #include #include #include /******************************************************************************* * Internal Functions * *******************************************************************************/ static int pdmR3CritSectDeleteOne(PVM pVM, PPDMCRITSECTINT pCritSect, PPDMCRITSECTINT pPrev, bool fFinal); /** * Initializes the critical section subcomponent. * * @returns VBox status code. * @param pVM The VM handle. * @remark Not to be confused with PDMR3CritSectInit and pdmR3CritSectInitDevice which are * for initializing a critical section. */ int pdmR3CritSectInit(PVM pVM) { STAM_REG(pVM, &pVM->pdm.s.StatQueuedCritSectLeaves, STAMTYPE_COUNTER, "/PDM/QueuedCritSectLeaves", STAMUNIT_OCCURENCES, "Number of times a critical section leave requesed needed to be queued for ring-3 execution."); return VINF_SUCCESS; } /** * Relocates all the critical sections. * * @param pVM The VM handle. */ void pdmR3CritSectRelocate(PVM pVM) { RTCritSectEnter(&pVM->pdm.s.MiscCritSect); for (PPDMCRITSECTINT pCur = pVM->pdm.s.pCritSects; pCur; pCur = pCur->pNext) pCur->pVMRC = pVM->pVMRC; RTCritSectLeave(&pVM->pdm.s.MiscCritSect); } /** * Deletes all remaining critical sections. * * This is called at the end of the termination process. * * @returns VBox status. * First error code, rest is lost. * @param pVM The VM handle. * @remark Don't confuse this with PDMR3CritSectDelete. */ VMMDECL(int) PDMR3CritSectTerm(PVM pVM) { int rc = VINF_SUCCESS; RTCritSectEnter(&pVM->pdm.s.MiscCritSect); while (pVM->pdm.s.pCritSects) { int rc2 = pdmR3CritSectDeleteOne(pVM, pVM->pdm.s.pCritSects, NULL, true /* final */); AssertRC(rc2); if (RT_FAILURE(rc2) && RT_SUCCESS(rc)) rc = rc2; } RTCritSectLeave(&pVM->pdm.s.MiscCritSect); RTCritSectDelete(&pVM->pdm.s.MiscCritSect); return rc; } /** * Initalizes a critical section and inserts it into the list. * * @returns VBox status code. * @param pVM The Vm handle. * @param pCritSect The critical section. * @param pvKey The owner key. * @param pszName The name of the critical section (for statistics). */ static int pdmR3CritSectInitOne(PVM pVM, PPDMCRITSECTINT pCritSect, void *pvKey, const char *pszName) { VM_ASSERT_EMT(pVM); /* * Allocate the semaphore. */ AssertCompile(sizeof(SUPSEMEVENT) == sizeof(pCritSect->Core.EventSem)); int rc = SUPSemEventCreate(pVM->pSession, (PSUPSEMEVENT)&pCritSect->Core.EventSem); if (RT_SUCCESS(rc)) { /* * Initialize the structure (first bit is c&p from RTCritSectInitEx). */ pCritSect->Core.u32Magic = RTCRITSECT_MAGIC; pCritSect->Core.fFlags = 0; pCritSect->Core.cNestings = 0; pCritSect->Core.cLockers = -1; pCritSect->Core.NativeThreadOwner = NIL_RTNATIVETHREAD; pCritSect->Core.Strict.ThreadOwner = NIL_RTTHREAD; pCritSect->Core.Strict.pszEnterFile = NULL; pCritSect->Core.Strict.u32EnterLine = 0; pCritSect->Core.Strict.uEnterId = 0; pCritSect->pVMR3 = pVM; pCritSect->pVMR0 = pVM->pVMR0; pCritSect->pVMRC = pVM->pVMRC; pCritSect->pvKey = pvKey; pCritSect->EventToSignal = NIL_RTSEMEVENT; pCritSect->pNext = pVM->pdm.s.pCritSects; pCritSect->pszName = RTStrDup(pszName); pVM->pdm.s.pCritSects = pCritSect; STAMR3RegisterF(pVM, &pCritSect->StatContentionRZLock, STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, STAMUNIT_OCCURENCES, NULL, "/PDM/CritSects/%s/ContentionRZLock", pszName); STAMR3RegisterF(pVM, &pCritSect->StatContentionRZUnlock,STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, STAMUNIT_OCCURENCES, NULL, "/PDM/CritSects/%s/ContentionRZUnlock", pszName); STAMR3RegisterF(pVM, &pCritSect->StatContentionR3, STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS, STAMUNIT_OCCURENCES, NULL, "/PDM/CritSects/%s/ContentionR3", pszName); #ifdef VBOX_WITH_STATISTICS STAMR3RegisterF(pVM, &pCritSect->StatLocked, STAMTYPE_PROFILE_ADV, STAMVISIBILITY_ALWAYS, STAMUNIT_TICKS_PER_OCCURENCE, NULL, "/PDM/CritSects/%s/Locked", pszName); #endif } return rc; } /** * Initializes a PDM critical section for internal use. * * The PDM critical sections are derived from the IPRT critical sections, but * works in GC as well. * * @returns VBox status code. * @param pVM The VM handle. * @param pDevIns Device instance. * @param pCritSect Pointer to the critical section. * @param pszName The name of the critical section (for statistics). * @thread EMT(0) */ VMMR3DECL(int) PDMR3CritSectInit(PVM pVM, PPDMCRITSECT pCritSect, const char *pszName) { #if HC_ARCH_BITS == 64 && GC_ARCH_BITS == 32 AssertCompile(sizeof(pCritSect->padding) >= sizeof(pCritSect->s)); #endif Assert(RT_ALIGN_P(pCritSect, sizeof(uintptr_t)) == pCritSect); return pdmR3CritSectInitOne(pVM, &pCritSect->s, pCritSect, pszName); } /** * Initializes a PDM critical section. * * The PDM critical sections are derived from the IPRT critical sections, but * works in GC as well. * * @returns VBox status code. * @param pVM The VM handle. * @param pDevIns Device instance. * @param pCritSect Pointer to the critical section. * @param pszName The name of the critical section (for statistics). */ int pdmR3CritSectInitDevice(PVM pVM, PPDMDEVINS pDevIns, PPDMCRITSECT pCritSect, const char *pszName) { return pdmR3CritSectInitOne(pVM, &pCritSect->s, pDevIns, pszName); } /** * Deletes one critical section. * * @returns Return code from RTCritSectDelete. * * @param pVM The VM handle. * @param pCritSect The critical section. * @param pPrev The previous critical section in the list. * @param fFinal Set if this is the final call and statistics shouldn't be deregistered. * * @remarks Caller must've entered the MiscCritSect. */ static int pdmR3CritSectDeleteOne(PVM pVM, PPDMCRITSECTINT pCritSect, PPDMCRITSECTINT pPrev, bool fFinal) { /* * Assert free waiters and so on (c&p from RTCritSectDelete). */ Assert(pCritSect->Core.u32Magic == RTCRITSECT_MAGIC); Assert(pCritSect->Core.cNestings == 0); Assert(pCritSect->Core.cLockers == -1); Assert(pCritSect->Core.NativeThreadOwner == NIL_RTNATIVETHREAD); Assert(RTCritSectIsOwner(&pVM->pdm.s.MiscCritSect)); /* * Unlink it. */ if (pPrev) pPrev->pNext = pCritSect->pNext; else pVM->pdm.s.pCritSects = pCritSect->pNext; /* * Delete it (parts taken from RTCritSectDelete). * In case someone is waiting we'll signal the semaphore cLockers + 1 times. */ ASMAtomicWriteU32(&pCritSect->Core.u32Magic, 0); SUPSEMEVENT hEvent = (SUPSEMEVENT)pCritSect->Core.EventSem; pCritSect->Core.EventSem = NIL_RTSEMEVENT; while (pCritSect->Core.cLockers-- >= 0) SUPSemEventSignal(pVM->pSession, hEvent); ASMAtomicWriteS32(&pCritSect->Core.cLockers, -1); int rc = SUPSemEventClose(pVM->pSession, hEvent); AssertRC(rc); pCritSect->pNext = NULL; pCritSect->pvKey = NULL; pCritSect->pVMR3 = NULL; pCritSect->pVMR0 = NIL_RTR0PTR; pCritSect->pVMRC = NIL_RTRCPTR; RTStrFree((char *)pCritSect->pszName); pCritSect->pszName = NULL; if (!fFinal) { STAMR3Deregister(pVM, &pCritSect->StatContentionRZLock); STAMR3Deregister(pVM, &pCritSect->StatContentionRZUnlock); STAMR3Deregister(pVM, &pCritSect->StatContentionR3); #ifdef VBOX_WITH_STATISTICS STAMR3Deregister(pVM, &pCritSect->StatLocked); #endif } return rc; } /** * Deletes all critical sections with a give initializer key. * * @returns VBox status code. * The entire list is processed on failure, so we'll only * return the first error code. This shouldn't be a problem * since errors really shouldn't happen here. * @param pVM The VM handle. * @param pvKey The initializer key. */ static int pdmR3CritSectDeleteByKey(PVM pVM, void *pvKey) { /* * Iterate the list and match key. */ int rc = VINF_SUCCESS; PPDMCRITSECTINT pPrev = NULL; RTCritSectEnter(&pVM->pdm.s.MiscCritSect); PPDMCRITSECTINT pCur = pVM->pdm.s.pCritSects; while (pCur) { if (pCur->pvKey == pvKey) { int rc2 = pdmR3CritSectDeleteOne(pVM, pCur, pPrev, false /* not final */); AssertRC(rc2); if (RT_FAILURE(rc2) && RT_SUCCESS(rc)) rc = rc2; } /* next */ pPrev = pCur; pCur = pCur->pNext; } RTCritSectLeave(&pVM->pdm.s.MiscCritSect); return rc; } /** * Deletes all undeleted critical sections initalized by a given device. * * @returns VBox status code. * @param pVM The VM handle. * @param pDevIns The device handle. */ int pdmR3CritSectDeleteDevice(PVM pVM, PPDMDEVINS pDevIns) { return pdmR3CritSectDeleteByKey(pVM, pDevIns); } /** * Deletes the critical section. * * @returns VBox status code. * @param pCritSect The PDM critical section to destroy. */ VMMR3DECL(int) PDMR3CritSectDelete(PPDMCRITSECT pCritSect) { if (!RTCritSectIsInitialized(&pCritSect->s.Core)) return VINF_SUCCESS; /* * Find and unlink it. */ PVM pVM = pCritSect->s.pVMR3; AssertReleaseReturn(pVM, VERR_INTERNAL_ERROR); PPDMCRITSECTINT pPrev = NULL; RTCritSectEnter(&pVM->pdm.s.MiscCritSect); PPDMCRITSECTINT pCur = pVM->pdm.s.pCritSects; while (pCur) { if (pCur == &pCritSect->s) { int rc = pdmR3CritSectDeleteOne(pVM, pCur, pPrev, false /* not final */); RTCritSectLeave(&pVM->pdm.s.MiscCritSect); return rc; } /* next */ pPrev = pCur; pCur = pCur->pNext; } RTCritSectLeave(&pVM->pdm.s.MiscCritSect); AssertReleaseMsgFailed(("pCritSect=%p wasn't found!\n", pCritSect)); return VERR_INTERNAL_ERROR; } /** * Gets the name of the critical section. * * * @returns Pointer to the critical section name (read only) on success, * NULL on failure (invalid critical section). * @param pCritSect The critical section. */ VMMR3DECL(const char *) PDMR3CritSectName(PCPDMCRITSECT pCritSect) { AssertPtrReturn(pCritSect, NULL); AssertReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC, NULL); return pCritSect->s.pszName; } /** * Yield the critical section if someone is waiting on it. * * When yielding, we'll leave the critical section and try to make sure the * other waiting threads get a chance of entering before we reclaim it. * * @retval true if yielded. * @retval false if not yielded. * @param pCritSect The critical section. */ VMMR3DECL(bool) PDMR3CritSectYield(PPDMCRITSECT pCritSect) { AssertPtrReturn(pCritSect, false); AssertReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC, false); Assert(pCritSect->s.Core.NativeThreadOwner == RTThreadNativeSelf()); /* No recursion allowed here. */ int32_t const cNestings = pCritSect->s.Core.cNestings; AssertReturn(cNestings == 1, false); int32_t const cLockers = ASMAtomicReadS32(&pCritSect->s.Core.cLockers); if (cLockers < cNestings) return false; PDMCritSectLeave(pCritSect); /* * If we're lucky, then one of the waiters has entered the lock already. * We spin a little bit in hope for this to happen so we can avoid the * yield deatour. */ if (ASMAtomicUoReadS32(&pCritSect->s.Core.cNestings) == 0) { int cLoops = 20; while ( cLoops > 0 && ASMAtomicUoReadS32(&pCritSect->s.Core.cNestings) == 0 && ASMAtomicUoReadS32(&pCritSect->s.Core.cLockers) >= 0) { ASMNopPause(); cLoops--; } if (cLoops == 0) RTThreadYield(); } int rc = PDMCritSectEnter(pCritSect, VERR_INTERNAL_ERROR); AssertLogRelRC(rc); return true; } /** * Schedule a event semaphore for signalling upon critsect exit. * * @returns VINF_SUCCESS on success. * @returns VERR_TOO_MANY_SEMAPHORES if an event was already scheduled. * @returns VERR_NOT_OWNER if we're not the critsect owner. * @returns VERR_SEM_DESTROYED if RTCritSectDelete was called while waiting. * * @param pCritSect The critical section. * @param EventToSignal The semapore that should be signalled. */ VMMR3DECL(int) PDMR3CritSectScheduleExitEvent(PPDMCRITSECT pCritSect, RTSEMEVENT EventToSignal) { Assert(EventToSignal != NIL_RTSEMEVENT); if (RT_UNLIKELY(!RTCritSectIsOwner(&pCritSect->s.Core))) return VERR_NOT_OWNER; if (RT_LIKELY( pCritSect->s.EventToSignal == NIL_RTSEMEVENT || pCritSect->s.EventToSignal == EventToSignal)) { pCritSect->s.EventToSignal = EventToSignal; return VINF_SUCCESS; } return VERR_TOO_MANY_SEMAPHORES; } /** * Counts the critical sections owned by the calling thread, optionally * returning a comma separated list naming them. * * This is for diagnostic purposes only. * * @returns Lock count. * * @param pVM The VM handle. * @param pszNames Where to return the critical section names. * @param cbNames The size of the buffer. */ VMMR3DECL(uint32_t) PDMR3CritSectCountOwned(PVM pVM, char *pszNames, size_t cbNames) { /* * Init the name buffer. */ size_t cchLeft = cbNames; if (cchLeft) { cchLeft--; pszNames[0] = pszNames[cchLeft] = '\0'; } /* * Iterate the critical sections. */ /* This is unsafe, but wtf. */ RTNATIVETHREAD const hNativeThread = RTThreadNativeSelf(); uint32_t cCritSects = 0; for (PPDMCRITSECTINT pCur = pVM->pdm.s.pCritSects; pCur; pCur = pCur->pNext) { /* Same as RTCritSectIsOwner(). */ if (pCur->Core.NativeThreadOwner == hNativeThread) { cCritSects++; /* * Copy the name if there is space. Fun stuff. */ if (cchLeft) { /* try add comma. */ if (cCritSects != 1) { *pszNames++ = ','; if (--cchLeft) { *pszNames++ = ' '; cchLeft--; } } /* try copy the name. */ if (cchLeft) { size_t const cchName = strlen(pCur->pszName); if (cchName < cchLeft) { memcpy(pszNames, pCur->pszName, cchName); pszNames += cchName; cchLeft -= cchName; } else { if (cchLeft > 2) { memcpy(pszNames, pCur->pszName, cchLeft - 2); pszNames += cchLeft - 2; cchLeft = 2; } while (cchLeft-- > 0) *pszNames++ = '+'; } } *pszNames = '\0'; } } } return cCritSects; } /** * Leave all critical sections the calling thread owns. * * @param pVM The VM handle. */ void PDMR3CritSectLeaveAll(PVM pVM) { RTNATIVETHREAD const hNativeSelf = RTThreadNativeSelf(); RTCritSectEnter(&pVM->pdm.s.MiscCritSect); for (PPDMCRITSECTINT pCur = pVM->pdm.s.pCritSects; pCur; pCur = pCur->pNext) { while ( pCur->Core.NativeThreadOwner == hNativeSelf && pCur->Core.cNestings > 0) PDMCritSectLeave((PPDMCRITSECT)pCur); } RTCritSectLeave(&pVM->pdm.s.MiscCritSect); }