VirtualBox

source: vbox/trunk/src/VBox/VMM/VMMR3/PDMBlkCache.cpp@ 55705

Last change on this file since 55705 was 55480, checked in by vboxsync, 10 years ago

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1/* $Id: PDMBlkCache.cpp 55480 2015-04-28 13:08:09Z vboxsync $ */
2/** @file
3 * PDM Block Cache.
4 */
5
6/*
7 * Copyright (C) 2006-2012 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/** @page pg_pdm_block_cache PDM Block Cache - The I/O cache
19 * This component implements an I/O cache based on the 2Q cache algorithm.
20 */
21
22/*******************************************************************************
23* Header Files *
24*******************************************************************************/
25#define LOG_GROUP LOG_GROUP_PDM_BLK_CACHE
26#include "PDMInternal.h"
27#include <iprt/asm.h>
28#include <iprt/mem.h>
29#include <iprt/path.h>
30#include <iprt/string.h>
31#include <VBox/log.h>
32#include <VBox/vmm/stam.h>
33#include <VBox/vmm/uvm.h>
34#include <VBox/vmm/vm.h>
35
36#include "PDMBlkCacheInternal.h"
37
38#ifdef VBOX_STRICT
39# define PDMACFILECACHE_IS_CRITSECT_OWNER(Cache) \
40 do \
41 { \
42 AssertMsg(RTCritSectIsOwner(&Cache->CritSect), \
43 ("Thread does not own critical section\n"));\
44 } while (0)
45
46# define PDMACFILECACHE_EP_IS_SEMRW_WRITE_OWNER(pEpCache) \
47 do \
48 { \
49 AssertMsg(RTSemRWIsWriteOwner(pEpCache->SemRWEntries), \
50 ("Thread is not exclusive owner of the per endpoint RW semaphore\n")); \
51 } while (0)
52
53# define PDMACFILECACHE_EP_IS_SEMRW_READ_OWNER(pEpCache) \
54 do \
55 { \
56 AssertMsg(RTSemRWIsReadOwner(pEpCache->SemRWEntries), \
57 ("Thread is not read owner of the per endpoint RW semaphore\n")); \
58 } while (0)
59
60#else
61# define PDMACFILECACHE_IS_CRITSECT_OWNER(Cache) do { } while (0)
62# define PDMACFILECACHE_EP_IS_SEMRW_WRITE_OWNER(pEpCache) do { } while (0)
63# define PDMACFILECACHE_EP_IS_SEMRW_READ_OWNER(pEpCache) do { } while (0)
64#endif
65
66#define PDM_BLK_CACHE_SAVED_STATE_VERSION 1
67
68/*******************************************************************************
69* Internal Functions *
70*******************************************************************************/
71
72static PPDMBLKCACHEENTRY pdmBlkCacheEntryAlloc(PPDMBLKCACHE pBlkCache,
73 uint64_t off, size_t cbData, uint8_t *pbBuffer);
74static bool pdmBlkCacheAddDirtyEntry(PPDMBLKCACHE pBlkCache, PPDMBLKCACHEENTRY pEntry);
75
76/**
77 * Decrement the reference counter of the given cache entry.
78 *
79 * @returns nothing.
80 * @param pEntry The entry to release.
81 */
82DECLINLINE(void) pdmBlkCacheEntryRelease(PPDMBLKCACHEENTRY pEntry)
83{
84 AssertMsg(pEntry->cRefs > 0, ("Trying to release a not referenced entry\n"));
85 ASMAtomicDecU32(&pEntry->cRefs);
86}
87
88/**
89 * Increment the reference counter of the given cache entry.
90 *
91 * @returns nothing.
92 * @param pEntry The entry to reference.
93 */
94DECLINLINE(void) pdmBlkCacheEntryRef(PPDMBLKCACHEENTRY pEntry)
95{
96 ASMAtomicIncU32(&pEntry->cRefs);
97}
98
99#ifdef VBOX_STRICT
100static void pdmBlkCacheValidate(PPDMBLKCACHEGLOBAL pCache)
101{
102 /* Amount of cached data should never exceed the maximum amount. */
103 AssertMsg(pCache->cbCached <= pCache->cbMax,
104 ("Current amount of cached data exceeds maximum\n"));
105
106 /* The amount of cached data in the LRU and FRU list should match cbCached */
107 AssertMsg(pCache->LruRecentlyUsedIn.cbCached + pCache->LruFrequentlyUsed.cbCached == pCache->cbCached,
108 ("Amount of cached data doesn't match\n"));
109
110 AssertMsg(pCache->LruRecentlyUsedOut.cbCached <= pCache->cbRecentlyUsedOutMax,
111 ("Paged out list exceeds maximum\n"));
112}
113#endif
114
115DECLINLINE(void) pdmBlkCacheLockEnter(PPDMBLKCACHEGLOBAL pCache)
116{
117 RTCritSectEnter(&pCache->CritSect);
118#ifdef VBOX_STRICT
119 pdmBlkCacheValidate(pCache);
120#endif
121}
122
123DECLINLINE(void) pdmBlkCacheLockLeave(PPDMBLKCACHEGLOBAL pCache)
124{
125#ifdef VBOX_STRICT
126 pdmBlkCacheValidate(pCache);
127#endif
128 RTCritSectLeave(&pCache->CritSect);
129}
130
131DECLINLINE(void) pdmBlkCacheSub(PPDMBLKCACHEGLOBAL pCache, uint32_t cbAmount)
132{
133 PDMACFILECACHE_IS_CRITSECT_OWNER(pCache);
134 pCache->cbCached -= cbAmount;
135}
136
137DECLINLINE(void) pdmBlkCacheAdd(PPDMBLKCACHEGLOBAL pCache, uint32_t cbAmount)
138{
139 PDMACFILECACHE_IS_CRITSECT_OWNER(pCache);
140 pCache->cbCached += cbAmount;
141}
142
143DECLINLINE(void) pdmBlkCacheListAdd(PPDMBLKLRULIST pList, uint32_t cbAmount)
144{
145 pList->cbCached += cbAmount;
146}
147
148DECLINLINE(void) pdmBlkCacheListSub(PPDMBLKLRULIST pList, uint32_t cbAmount)
149{
150 pList->cbCached -= cbAmount;
151}
152
153#ifdef PDMACFILECACHE_WITH_LRULIST_CHECKS
154/**
155 * Checks consistency of a LRU list.
156 *
157 * @returns nothing
158 * @param pList The LRU list to check.
159 * @param pNotInList Element which is not allowed to occur in the list.
160 */
161static void pdmBlkCacheCheckList(PPDMBLKLRULIST pList, PPDMBLKCACHEENTRY pNotInList)
162{
163 PPDMBLKCACHEENTRY pCurr = pList->pHead;
164
165 /* Check that there are no double entries and no cycles in the list. */
166 while (pCurr)
167 {
168 PPDMBLKCACHEENTRY pNext = pCurr->pNext;
169
170 while (pNext)
171 {
172 AssertMsg(pCurr != pNext,
173 ("Entry %#p is at least two times in list %#p or there is a cycle in the list\n",
174 pCurr, pList));
175 pNext = pNext->pNext;
176 }
177
178 AssertMsg(pCurr != pNotInList, ("Not allowed entry %#p is in list\n", pCurr));
179
180 if (!pCurr->pNext)
181 AssertMsg(pCurr == pList->pTail, ("End of list reached but last element is not list tail\n"));
182
183 pCurr = pCurr->pNext;
184 }
185}
186#endif
187
188/**
189 * Unlinks a cache entry from the LRU list it is assigned to.
190 *
191 * @returns nothing.
192 * @param pEntry The entry to unlink.
193 */
194static void pdmBlkCacheEntryRemoveFromList(PPDMBLKCACHEENTRY pEntry)
195{
196 PPDMBLKLRULIST pList = pEntry->pList;
197 PPDMBLKCACHEENTRY pPrev, pNext;
198
199 LogFlowFunc((": Deleting entry %#p from list %#p\n", pEntry, pList));
200
201 AssertPtr(pList);
202
203#ifdef PDMACFILECACHE_WITH_LRULIST_CHECKS
204 pdmBlkCacheCheckList(pList, NULL);
205#endif
206
207 pPrev = pEntry->pPrev;
208 pNext = pEntry->pNext;
209
210 AssertMsg(pEntry != pPrev, ("Entry links to itself as previous element\n"));
211 AssertMsg(pEntry != pNext, ("Entry links to itself as next element\n"));
212
213 if (pPrev)
214 pPrev->pNext = pNext;
215 else
216 {
217 pList->pHead = pNext;
218
219 if (pNext)
220 pNext->pPrev = NULL;
221 }
222
223 if (pNext)
224 pNext->pPrev = pPrev;
225 else
226 {
227 pList->pTail = pPrev;
228
229 if (pPrev)
230 pPrev->pNext = NULL;
231 }
232
233 pEntry->pList = NULL;
234 pEntry->pPrev = NULL;
235 pEntry->pNext = NULL;
236 pdmBlkCacheListSub(pList, pEntry->cbData);
237#ifdef PDMACFILECACHE_WITH_LRULIST_CHECKS
238 pdmBlkCacheCheckList(pList, pEntry);
239#endif
240}
241
242/**
243 * Adds a cache entry to the given LRU list unlinking it from the currently
244 * assigned list if needed.
245 *
246 * @returns nothing.
247 * @param pList List to the add entry to.
248 * @param pEntry Entry to add.
249 */
250static void pdmBlkCacheEntryAddToList(PPDMBLKLRULIST pList, PPDMBLKCACHEENTRY pEntry)
251{
252 LogFlowFunc((": Adding entry %#p to list %#p\n", pEntry, pList));
253#ifdef PDMACFILECACHE_WITH_LRULIST_CHECKS
254 pdmBlkCacheCheckList(pList, NULL);
255#endif
256
257 /* Remove from old list if needed */
258 if (pEntry->pList)
259 pdmBlkCacheEntryRemoveFromList(pEntry);
260
261 pEntry->pNext = pList->pHead;
262 if (pList->pHead)
263 pList->pHead->pPrev = pEntry;
264 else
265 {
266 Assert(!pList->pTail);
267 pList->pTail = pEntry;
268 }
269
270 pEntry->pPrev = NULL;
271 pList->pHead = pEntry;
272 pdmBlkCacheListAdd(pList, pEntry->cbData);
273 pEntry->pList = pList;
274#ifdef PDMACFILECACHE_WITH_LRULIST_CHECKS
275 pdmBlkCacheCheckList(pList, NULL);
276#endif
277}
278
279/**
280 * Destroys a LRU list freeing all entries.
281 *
282 * @returns nothing
283 * @param pList Pointer to the LRU list to destroy.
284 *
285 * @note The caller must own the critical section of the cache.
286 */
287static void pdmBlkCacheDestroyList(PPDMBLKLRULIST pList)
288{
289 while (pList->pHead)
290 {
291 PPDMBLKCACHEENTRY pEntry = pList->pHead;
292
293 pList->pHead = pEntry->pNext;
294
295 AssertMsg(!(pEntry->fFlags & (PDMBLKCACHE_ENTRY_IO_IN_PROGRESS | PDMBLKCACHE_ENTRY_IS_DIRTY)),
296 ("Entry is dirty and/or still in progress fFlags=%#x\n", pEntry->fFlags));
297
298 RTMemPageFree(pEntry->pbData, pEntry->cbData);
299 RTMemFree(pEntry);
300 }
301}
302
303/**
304 * Tries to remove the given amount of bytes from a given list in the cache
305 * moving the entries to one of the given ghosts lists
306 *
307 * @returns Amount of data which could be freed.
308 * @param pCache Pointer to the global cache data.
309 * @param cbData The amount of the data to free.
310 * @param pListSrc The source list to evict data from.
311 * @param pGhostListSrc The ghost list removed entries should be moved to
312 * NULL if the entry should be freed.
313 * @param fReuseBuffer Flag whether a buffer should be reused if it has the same size
314 * @param ppbBuf Where to store the address of the buffer if an entry with the
315 * same size was found and fReuseBuffer is true.
316 *
317 * @note This function may return fewer bytes than requested because entries
318 * may be marked as non evictable if they are used for I/O at the
319 * moment.
320 */
321static size_t pdmBlkCacheEvictPagesFrom(PPDMBLKCACHEGLOBAL pCache, size_t cbData,
322 PPDMBLKLRULIST pListSrc, PPDMBLKLRULIST pGhostListDst,
323 bool fReuseBuffer, uint8_t **ppbBuffer)
324{
325 size_t cbEvicted = 0;
326
327 PDMACFILECACHE_IS_CRITSECT_OWNER(pCache);
328
329 AssertMsg(cbData > 0, ("Evicting 0 bytes not possible\n"));
330 AssertMsg( !pGhostListDst
331 || (pGhostListDst == &pCache->LruRecentlyUsedOut),
332 ("Destination list must be NULL or the recently used but paged out list\n"));
333
334 if (fReuseBuffer)
335 {
336 AssertPtr(ppbBuffer);
337 *ppbBuffer = NULL;
338 }
339
340 /* Start deleting from the tail. */
341 PPDMBLKCACHEENTRY pEntry = pListSrc->pTail;
342
343 while ((cbEvicted < cbData) && pEntry)
344 {
345 PPDMBLKCACHEENTRY pCurr = pEntry;
346
347 pEntry = pEntry->pPrev;
348
349 /* We can't evict pages which are currently in progress or dirty but not in progress */
350 if ( !(pCurr->fFlags & PDMBLKCACHE_NOT_EVICTABLE)
351 && (ASMAtomicReadU32(&pCurr->cRefs) == 0))
352 {
353 /* Ok eviction candidate. Grab the endpoint semaphore and check again
354 * because somebody else might have raced us. */
355 PPDMBLKCACHE pBlkCache = pCurr->pBlkCache;
356 RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
357
358 if (!(pCurr->fFlags & PDMBLKCACHE_NOT_EVICTABLE)
359 && (ASMAtomicReadU32(&pCurr->cRefs) == 0))
360 {
361 LogFlow(("Evicting entry %#p (%u bytes)\n", pCurr, pCurr->cbData));
362
363 if (fReuseBuffer && pCurr->cbData == cbData)
364 {
365 STAM_COUNTER_INC(&pCache->StatBuffersReused);
366 *ppbBuffer = pCurr->pbData;
367 }
368 else if (pCurr->pbData)
369 RTMemPageFree(pCurr->pbData, pCurr->cbData);
370
371 pCurr->pbData = NULL;
372 cbEvicted += pCurr->cbData;
373
374 pdmBlkCacheEntryRemoveFromList(pCurr);
375 pdmBlkCacheSub(pCache, pCurr->cbData);
376
377 if (pGhostListDst)
378 {
379 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
380
381 PPDMBLKCACHEENTRY pGhostEntFree = pGhostListDst->pTail;
382
383 /* We have to remove the last entries from the paged out list. */
384 while ( pGhostListDst->cbCached + pCurr->cbData > pCache->cbRecentlyUsedOutMax
385 && pGhostEntFree)
386 {
387 PPDMBLKCACHEENTRY pFree = pGhostEntFree;
388 PPDMBLKCACHE pBlkCacheFree = pFree->pBlkCache;
389
390 pGhostEntFree = pGhostEntFree->pPrev;
391
392 RTSemRWRequestWrite(pBlkCacheFree->SemRWEntries, RT_INDEFINITE_WAIT);
393
394 if (ASMAtomicReadU32(&pFree->cRefs) == 0)
395 {
396 pdmBlkCacheEntryRemoveFromList(pFree);
397
398 STAM_PROFILE_ADV_START(&pCache->StatTreeRemove, Cache);
399 RTAvlrU64Remove(pBlkCacheFree->pTree, pFree->Core.Key);
400 STAM_PROFILE_ADV_STOP(&pCache->StatTreeRemove, Cache);
401
402 RTMemFree(pFree);
403 }
404
405 RTSemRWReleaseWrite(pBlkCacheFree->SemRWEntries);
406 }
407
408 if (pGhostListDst->cbCached + pCurr->cbData > pCache->cbRecentlyUsedOutMax)
409 {
410 /* Couldn't remove enough entries. Delete */
411 STAM_PROFILE_ADV_START(&pCache->StatTreeRemove, Cache);
412 RTAvlrU64Remove(pCurr->pBlkCache->pTree, pCurr->Core.Key);
413 STAM_PROFILE_ADV_STOP(&pCache->StatTreeRemove, Cache);
414
415 RTMemFree(pCurr);
416 }
417 else
418 pdmBlkCacheEntryAddToList(pGhostListDst, pCurr);
419 }
420 else
421 {
422 /* Delete the entry from the AVL tree it is assigned to. */
423 STAM_PROFILE_ADV_START(&pCache->StatTreeRemove, Cache);
424 RTAvlrU64Remove(pCurr->pBlkCache->pTree, pCurr->Core.Key);
425 STAM_PROFILE_ADV_STOP(&pCache->StatTreeRemove, Cache);
426
427 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
428 RTMemFree(pCurr);
429 }
430 }
431
432 }
433 else
434 LogFlow(("Entry %#p (%u bytes) is still in progress and can't be evicted\n", pCurr, pCurr->cbData));
435 }
436
437 return cbEvicted;
438}
439
440static bool pdmBlkCacheReclaim(PPDMBLKCACHEGLOBAL pCache, size_t cbData, bool fReuseBuffer, uint8_t **ppbBuffer)
441{
442 size_t cbRemoved = 0;
443
444 if ((pCache->cbCached + cbData) < pCache->cbMax)
445 return true;
446 else if ((pCache->LruRecentlyUsedIn.cbCached + cbData) > pCache->cbRecentlyUsedInMax)
447 {
448 /* Try to evict as many bytes as possible from A1in */
449 cbRemoved = pdmBlkCacheEvictPagesFrom(pCache, cbData, &pCache->LruRecentlyUsedIn,
450 &pCache->LruRecentlyUsedOut, fReuseBuffer, ppbBuffer);
451
452 /*
453 * If it was not possible to remove enough entries
454 * try the frequently accessed cache.
455 */
456 if (cbRemoved < cbData)
457 {
458 Assert(!fReuseBuffer || !*ppbBuffer); /* It is not possible that we got a buffer with the correct size but we didn't freed enough data. */
459
460 /*
461 * If we removed something we can't pass the reuse buffer flag anymore because
462 * we don't need to evict that much data
463 */
464 if (!cbRemoved)
465 cbRemoved += pdmBlkCacheEvictPagesFrom(pCache, cbData, &pCache->LruFrequentlyUsed,
466 NULL, fReuseBuffer, ppbBuffer);
467 else
468 cbRemoved += pdmBlkCacheEvictPagesFrom(pCache, cbData - cbRemoved, &pCache->LruFrequentlyUsed,
469 NULL, false, NULL);
470 }
471 }
472 else
473 {
474 /* We have to remove entries from frequently access list. */
475 cbRemoved = pdmBlkCacheEvictPagesFrom(pCache, cbData, &pCache->LruFrequentlyUsed,
476 NULL, fReuseBuffer, ppbBuffer);
477 }
478
479 LogFlowFunc((": removed %u bytes, requested %u\n", cbRemoved, cbData));
480 return (cbRemoved >= cbData);
481}
482
483DECLINLINE(int) pdmBlkCacheEnqueue(PPDMBLKCACHE pBlkCache, uint64_t off, size_t cbXfer, PPDMBLKCACHEIOXFER pIoXfer)
484{
485 int rc = VINF_SUCCESS;
486
487 LogFlowFunc(("%s: Enqueuing hIoXfer=%#p enmXferDir=%d\n",
488 __FUNCTION__, pIoXfer, pIoXfer->enmXferDir));
489
490 switch (pBlkCache->enmType)
491 {
492 case PDMBLKCACHETYPE_DEV:
493 {
494 rc = pBlkCache->u.Dev.pfnXferEnqueue(pBlkCache->u.Dev.pDevIns,
495 pIoXfer->enmXferDir,
496 off, cbXfer,
497 &pIoXfer->SgBuf, pIoXfer);
498 break;
499 }
500 case PDMBLKCACHETYPE_DRV:
501 {
502 rc = pBlkCache->u.Drv.pfnXferEnqueue(pBlkCache->u.Drv.pDrvIns,
503 pIoXfer->enmXferDir,
504 off, cbXfer,
505 &pIoXfer->SgBuf, pIoXfer);
506 break;
507 }
508 case PDMBLKCACHETYPE_USB:
509 {
510 rc = pBlkCache->u.Usb.pfnXferEnqueue(pBlkCache->u.Usb.pUsbIns,
511 pIoXfer->enmXferDir,
512 off, cbXfer,
513 &pIoXfer->SgBuf, pIoXfer);
514 break;
515 }
516 case PDMBLKCACHETYPE_INTERNAL:
517 {
518 rc = pBlkCache->u.Int.pfnXferEnqueue(pBlkCache->u.Int.pvUser,
519 pIoXfer->enmXferDir,
520 off, cbXfer,
521 &pIoXfer->SgBuf, pIoXfer);
522 break;
523 }
524 default:
525 AssertMsgFailed(("Unknown block cache type!\n"));
526 }
527
528 LogFlowFunc(("%s: returns rc=%Rrc\n", __FUNCTION__, rc));
529 return rc;
530}
531
532/**
533 * Initiates a read I/O task for the given entry.
534 *
535 * @returns VBox status code.
536 * @param pEntry The entry to fetch the data to.
537 */
538static int pdmBlkCacheEntryReadFromMedium(PPDMBLKCACHEENTRY pEntry)
539{
540 PPDMBLKCACHE pBlkCache = pEntry->pBlkCache;
541 LogFlowFunc((": Reading data into cache entry %#p\n", pEntry));
542
543 /* Make sure no one evicts the entry while it is accessed. */
544 pEntry->fFlags |= PDMBLKCACHE_ENTRY_IO_IN_PROGRESS;
545
546 PPDMBLKCACHEIOXFER pIoXfer = (PPDMBLKCACHEIOXFER)RTMemAllocZ(sizeof(PDMBLKCACHEIOXFER));
547 if (RT_UNLIKELY(!pIoXfer))
548 return VERR_NO_MEMORY;
549
550 AssertMsg(pEntry->pbData, ("Entry is in ghost state\n"));
551
552 pIoXfer->fIoCache = true;
553 pIoXfer->pEntry = pEntry;
554 pIoXfer->SgSeg.pvSeg = pEntry->pbData;
555 pIoXfer->SgSeg.cbSeg = pEntry->cbData;
556 pIoXfer->enmXferDir = PDMBLKCACHEXFERDIR_READ;
557 RTSgBufInit(&pIoXfer->SgBuf, &pIoXfer->SgSeg, 1);
558
559 return pdmBlkCacheEnqueue(pBlkCache, pEntry->Core.Key, pEntry->cbData, pIoXfer);
560}
561
562/**
563 * Initiates a write I/O task for the given entry.
564 *
565 * @returns nothing.
566 * @param pEntry The entry to read the data from.
567 */
568static int pdmBlkCacheEntryWriteToMedium(PPDMBLKCACHEENTRY pEntry)
569{
570 PPDMBLKCACHE pBlkCache = pEntry->pBlkCache;
571 LogFlowFunc((": Writing data from cache entry %#p\n", pEntry));
572
573 /* Make sure no one evicts the entry while it is accessed. */
574 pEntry->fFlags |= PDMBLKCACHE_ENTRY_IO_IN_PROGRESS;
575
576 PPDMBLKCACHEIOXFER pIoXfer = (PPDMBLKCACHEIOXFER)RTMemAllocZ(sizeof(PDMBLKCACHEIOXFER));
577 if (RT_UNLIKELY(!pIoXfer))
578 return VERR_NO_MEMORY;
579
580 AssertMsg(pEntry->pbData, ("Entry is in ghost state\n"));
581
582 pIoXfer->fIoCache = true;
583 pIoXfer->pEntry = pEntry;
584 pIoXfer->SgSeg.pvSeg = pEntry->pbData;
585 pIoXfer->SgSeg.cbSeg = pEntry->cbData;
586 pIoXfer->enmXferDir = PDMBLKCACHEXFERDIR_WRITE;
587 RTSgBufInit(&pIoXfer->SgBuf, &pIoXfer->SgSeg, 1);
588
589 return pdmBlkCacheEnqueue(pBlkCache, pEntry->Core.Key, pEntry->cbData, pIoXfer);
590}
591
592/**
593 * Passthrough a part of a request directly to the I/O manager
594 * handling the endpoint.
595 *
596 * @returns VBox status code.
597 * @param pEndpoint The endpoint.
598 * @param pTask The task.
599 * @param pIoMemCtx The I/O memory context to use.
600 * @param offStart Offset to start transfer from.
601 * @param cbData Amount of data to transfer.
602 * @param enmTransferType The transfer type (read/write)
603 */
604static int pdmBlkCacheRequestPassthrough(PPDMBLKCACHE pBlkCache, PPDMBLKCACHEREQ pReq,
605 PRTSGBUF pSgBuf, uint64_t offStart, size_t cbData,
606 PDMBLKCACHEXFERDIR enmXferDir)
607{
608
609 PPDMBLKCACHEIOXFER pIoXfer = (PPDMBLKCACHEIOXFER)RTMemAllocZ(sizeof(PDMBLKCACHEIOXFER));
610 if (RT_UNLIKELY(!pIoXfer))
611 return VERR_NO_MEMORY;
612
613 ASMAtomicIncU32(&pReq->cXfersPending);
614 pIoXfer->fIoCache = false;
615 pIoXfer->pReq = pReq;
616 pIoXfer->enmXferDir = enmXferDir;
617 if (pSgBuf)
618 {
619 RTSgBufClone(&pIoXfer->SgBuf, pSgBuf);
620 RTSgBufAdvance(pSgBuf, cbData);
621 }
622
623 return pdmBlkCacheEnqueue(pBlkCache, offStart, cbData, pIoXfer);
624}
625
626/**
627 * Commit a single dirty entry to the endpoint
628 *
629 * @returns nothing
630 * @param pEntry The entry to commit.
631 */
632static void pdmBlkCacheEntryCommit(PPDMBLKCACHEENTRY pEntry)
633{
634 AssertMsg( (pEntry->fFlags & PDMBLKCACHE_ENTRY_IS_DIRTY)
635 && !(pEntry->fFlags & PDMBLKCACHE_ENTRY_IO_IN_PROGRESS),
636 ("Invalid flags set for entry %#p\n", pEntry));
637
638 pdmBlkCacheEntryWriteToMedium(pEntry);
639}
640
641/**
642 * Commit all dirty entries for a single endpoint.
643 *
644 * @returns nothing.
645 * @param pBlkCache The endpoint cache to commit.
646 */
647static void pdmBlkCacheCommit(PPDMBLKCACHE pBlkCache)
648{
649 uint32_t cbCommitted = 0;
650
651 /* Return if the cache was suspended. */
652 if (pBlkCache->fSuspended)
653 return;
654
655 RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
656
657 /* The list is moved to a new header to reduce locking overhead. */
658 RTLISTANCHOR ListDirtyNotCommitted;
659
660 RTListInit(&ListDirtyNotCommitted);
661 RTSpinlockAcquire(pBlkCache->LockList);
662 RTListMove(&ListDirtyNotCommitted, &pBlkCache->ListDirtyNotCommitted);
663 RTSpinlockRelease(pBlkCache->LockList);
664
665 if (!RTListIsEmpty(&ListDirtyNotCommitted))
666 {
667 PPDMBLKCACHEENTRY pEntry = RTListGetFirst(&ListDirtyNotCommitted, PDMBLKCACHEENTRY, NodeNotCommitted);
668
669 while (!RTListNodeIsLast(&ListDirtyNotCommitted, &pEntry->NodeNotCommitted))
670 {
671 PPDMBLKCACHEENTRY pNext = RTListNodeGetNext(&pEntry->NodeNotCommitted, PDMBLKCACHEENTRY,
672 NodeNotCommitted);
673 pdmBlkCacheEntryCommit(pEntry);
674 cbCommitted += pEntry->cbData;
675 RTListNodeRemove(&pEntry->NodeNotCommitted);
676 pEntry = pNext;
677 }
678
679 /* Commit the last endpoint */
680 Assert(RTListNodeIsLast(&ListDirtyNotCommitted, &pEntry->NodeNotCommitted));
681 pdmBlkCacheEntryCommit(pEntry);
682 cbCommitted += pEntry->cbData;
683 RTListNodeRemove(&pEntry->NodeNotCommitted);
684 AssertMsg(RTListIsEmpty(&ListDirtyNotCommitted),
685 ("Committed all entries but list is not empty\n"));
686 }
687
688 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
689 AssertMsg(pBlkCache->pCache->cbDirty >= cbCommitted,
690 ("Number of committed bytes exceeds number of dirty bytes\n"));
691 uint32_t cbDirtyOld = ASMAtomicSubU32(&pBlkCache->pCache->cbDirty, cbCommitted);
692
693 /* Reset the commit timer if we don't have any dirty bits. */
694 if ( !(cbDirtyOld - cbCommitted)
695 && pBlkCache->pCache->u32CommitTimeoutMs != 0)
696 TMTimerStop(pBlkCache->pCache->pTimerCommit);
697}
698
699/**
700 * Commit all dirty entries in the cache.
701 *
702 * @returns nothing.
703 * @param pCache The global cache instance.
704 */
705static void pdmBlkCacheCommitDirtyEntries(PPDMBLKCACHEGLOBAL pCache)
706{
707 bool fCommitInProgress = ASMAtomicXchgBool(&pCache->fCommitInProgress, true);
708
709 if (!fCommitInProgress)
710 {
711 pdmBlkCacheLockEnter(pCache);
712 Assert(!RTListIsEmpty(&pCache->ListUsers));
713
714 PPDMBLKCACHE pBlkCache = RTListGetFirst(&pCache->ListUsers, PDMBLKCACHE, NodeCacheUser);
715 AssertPtr(pBlkCache);
716
717 while (!RTListNodeIsLast(&pCache->ListUsers, &pBlkCache->NodeCacheUser))
718 {
719 pdmBlkCacheCommit(pBlkCache);
720
721 pBlkCache = RTListNodeGetNext(&pBlkCache->NodeCacheUser, PDMBLKCACHE,
722 NodeCacheUser);
723 }
724
725 /* Commit the last endpoint */
726 Assert(RTListNodeIsLast(&pCache->ListUsers, &pBlkCache->NodeCacheUser));
727 pdmBlkCacheCommit(pBlkCache);
728
729 pdmBlkCacheLockLeave(pCache);
730 ASMAtomicWriteBool(&pCache->fCommitInProgress, false);
731 }
732}
733
734/**
735 * Adds the given entry as a dirty to the cache.
736 *
737 * @returns Flag whether the amount of dirty bytes in the cache exceeds the threshold
738 * @param pBlkCache The endpoint cache the entry belongs to.
739 * @param pEntry The entry to add.
740 */
741static bool pdmBlkCacheAddDirtyEntry(PPDMBLKCACHE pBlkCache, PPDMBLKCACHEENTRY pEntry)
742{
743 bool fDirtyBytesExceeded = false;
744 PPDMBLKCACHEGLOBAL pCache = pBlkCache->pCache;
745
746 /* If the commit timer is disabled we commit right away. */
747 if (pCache->u32CommitTimeoutMs == 0)
748 {
749 pEntry->fFlags |= PDMBLKCACHE_ENTRY_IS_DIRTY;
750 pdmBlkCacheEntryCommit(pEntry);
751 }
752 else if (!(pEntry->fFlags & PDMBLKCACHE_ENTRY_IS_DIRTY))
753 {
754 pEntry->fFlags |= PDMBLKCACHE_ENTRY_IS_DIRTY;
755
756 RTSpinlockAcquire(pBlkCache->LockList);
757 RTListAppend(&pBlkCache->ListDirtyNotCommitted, &pEntry->NodeNotCommitted);
758 RTSpinlockRelease(pBlkCache->LockList);
759
760 uint32_t cbDirty = ASMAtomicAddU32(&pCache->cbDirty, pEntry->cbData);
761
762 /* Prevent committing if the VM was suspended. */
763 if (RT_LIKELY(!ASMAtomicReadBool(&pCache->fIoErrorVmSuspended)))
764 fDirtyBytesExceeded = (cbDirty + pEntry->cbData >= pCache->cbCommitDirtyThreshold);
765 else if (!cbDirty && pCache->u32CommitTimeoutMs > 0)
766 {
767 /* Arm the commit timer. */
768 TMTimerSetMillies(pCache->pTimerCommit, pCache->u32CommitTimeoutMs);
769 }
770 }
771
772 return fDirtyBytesExceeded;
773}
774
775static PPDMBLKCACHE pdmR3BlkCacheFindById(PPDMBLKCACHEGLOBAL pBlkCacheGlobal, const char *pcszId)
776{
777 bool fFound = false;
778 PPDMBLKCACHE pBlkCache = NULL;
779
780 RTListForEach(&pBlkCacheGlobal->ListUsers, pBlkCache, PDMBLKCACHE, NodeCacheUser)
781 {
782 if (!RTStrCmp(pBlkCache->pszId, pcszId))
783 {
784 fFound = true;
785 break;
786 }
787 }
788
789 return fFound ? pBlkCache : NULL;
790}
791
792/**
793 * Commit timer callback.
794 */
795static DECLCALLBACK(void) pdmBlkCacheCommitTimerCallback(PVM pVM, PTMTIMER pTimer, void *pvUser)
796{
797 PPDMBLKCACHEGLOBAL pCache = (PPDMBLKCACHEGLOBAL)pvUser;
798 NOREF(pVM); NOREF(pTimer);
799
800 LogFlowFunc(("Commit interval expired, commiting dirty entries\n"));
801
802 if ( ASMAtomicReadU32(&pCache->cbDirty) > 0
803 && !ASMAtomicReadBool(&pCache->fIoErrorVmSuspended))
804 pdmBlkCacheCommitDirtyEntries(pCache);
805
806 LogFlowFunc(("Entries committed, going to sleep\n"));
807}
808
809static DECLCALLBACK(int) pdmR3BlkCacheSaveExec(PVM pVM, PSSMHANDLE pSSM)
810{
811 PPDMBLKCACHEGLOBAL pBlkCacheGlobal = pVM->pUVM->pdm.s.pBlkCacheGlobal;
812
813 AssertPtr(pBlkCacheGlobal);
814
815 pdmBlkCacheLockEnter(pBlkCacheGlobal);
816
817 SSMR3PutU32(pSSM, pBlkCacheGlobal->cRefs);
818
819 /* Go through the list and save all dirty entries. */
820 PPDMBLKCACHE pBlkCache;
821 RTListForEach(&pBlkCacheGlobal->ListUsers, pBlkCache, PDMBLKCACHE, NodeCacheUser)
822 {
823 uint32_t cEntries = 0;
824 PPDMBLKCACHEENTRY pEntry;
825
826 RTSemRWRequestRead(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
827 SSMR3PutU32(pSSM, (uint32_t)strlen(pBlkCache->pszId));
828 SSMR3PutStrZ(pSSM, pBlkCache->pszId);
829
830 /* Count the number of entries to safe. */
831 RTListForEach(&pBlkCache->ListDirtyNotCommitted, pEntry, PDMBLKCACHEENTRY, NodeNotCommitted)
832 {
833 cEntries++;
834 }
835
836 SSMR3PutU32(pSSM, cEntries);
837
838 /* Walk the list of all dirty entries and save them. */
839 RTListForEach(&pBlkCache->ListDirtyNotCommitted, pEntry, PDMBLKCACHEENTRY, NodeNotCommitted)
840 {
841 /* A few sanity checks. */
842 AssertMsg(!pEntry->cRefs, ("The entry is still referenced\n"));
843 AssertMsg(pEntry->fFlags & PDMBLKCACHE_ENTRY_IS_DIRTY, ("Entry is not dirty\n"));
844 AssertMsg(!(pEntry->fFlags & ~PDMBLKCACHE_ENTRY_IS_DIRTY), ("Invalid flags set\n"));
845 AssertMsg(!pEntry->pWaitingHead && !pEntry->pWaitingTail, ("There are waiting requests\n"));
846 AssertMsg( pEntry->pList == &pBlkCacheGlobal->LruRecentlyUsedIn
847 || pEntry->pList == &pBlkCacheGlobal->LruFrequentlyUsed,
848 ("Invalid list\n"));
849 AssertMsg(pEntry->cbData == pEntry->Core.KeyLast - pEntry->Core.Key + 1,
850 ("Size and range do not match\n"));
851
852 /* Save */
853 SSMR3PutU64(pSSM, pEntry->Core.Key);
854 SSMR3PutU32(pSSM, pEntry->cbData);
855 SSMR3PutMem(pSSM, pEntry->pbData, pEntry->cbData);
856 }
857
858 RTSemRWReleaseRead(pBlkCache->SemRWEntries);
859 }
860
861 pdmBlkCacheLockLeave(pBlkCacheGlobal);
862
863 /* Terminator */
864 return SSMR3PutU32(pSSM, UINT32_MAX);
865}
866
867static DECLCALLBACK(int) pdmR3BlkCacheLoadExec(PVM pVM, PSSMHANDLE pSSM, uint32_t uVersion, uint32_t uPass)
868{
869 PPDMBLKCACHEGLOBAL pBlkCacheGlobal = pVM->pUVM->pdm.s.pBlkCacheGlobal;
870 uint32_t cRefs;
871
872 NOREF(uPass);
873 AssertPtr(pBlkCacheGlobal);
874
875 pdmBlkCacheLockEnter(pBlkCacheGlobal);
876
877 if (uVersion != PDM_BLK_CACHE_SAVED_STATE_VERSION)
878 return VERR_SSM_UNSUPPORTED_DATA_UNIT_VERSION;
879
880 SSMR3GetU32(pSSM, &cRefs);
881
882 /*
883 * Fewer users in the saved state than in the current VM are allowed
884 * because that means that there are only new ones which don't have any saved state
885 * which can get lost.
886 * More saved state entries than registered cache users are only allowed if the
887 * missing users don't have any data saved in the cache.
888 */
889 int rc = VINF_SUCCESS;
890 char *pszId = NULL;
891
892 while ( cRefs > 0
893 && RT_SUCCESS(rc))
894 {
895 PPDMBLKCACHE pBlkCache = NULL;
896 uint32_t cbId = 0;
897
898 SSMR3GetU32(pSSM, &cbId);
899 Assert(cbId > 0);
900
901 cbId++; /* Include terminator */
902 pszId = (char *)RTMemAllocZ(cbId * sizeof(char));
903 if (!pszId)
904 {
905 rc = VERR_NO_MEMORY;
906 break;
907 }
908
909 rc = SSMR3GetStrZ(pSSM, pszId, cbId);
910 AssertRC(rc);
911
912 /* Search for the block cache with the provided id. */
913 pBlkCache = pdmR3BlkCacheFindById(pBlkCacheGlobal, pszId);
914
915 /* Get the entries */
916 uint32_t cEntries;
917 SSMR3GetU32(pSSM, &cEntries);
918
919 if (!pBlkCache && (cEntries > 0))
920 {
921 rc = SSMR3SetCfgError(pSSM, RT_SRC_POS,
922 N_("The VM is missing a block device and there is data in the cache. Please make sure the source and target VMs have compatible storage configurations"));
923 break;
924 }
925
926 RTMemFree(pszId);
927 pszId = NULL;
928
929 while (cEntries > 0)
930 {
931 PPDMBLKCACHEENTRY pEntry;
932 uint64_t off;
933 uint32_t cbEntry;
934
935 SSMR3GetU64(pSSM, &off);
936 SSMR3GetU32(pSSM, &cbEntry);
937
938 pEntry = pdmBlkCacheEntryAlloc(pBlkCache, off, cbEntry, NULL);
939 if (!pEntry)
940 {
941 rc = VERR_NO_MEMORY;
942 break;
943 }
944
945 rc = SSMR3GetMem(pSSM, pEntry->pbData, cbEntry);
946 if (RT_FAILURE(rc))
947 {
948 RTMemFree(pEntry->pbData);
949 RTMemFree(pEntry);
950 break;
951 }
952
953 /* Insert into the tree. */
954 bool fInserted = RTAvlrU64Insert(pBlkCache->pTree, &pEntry->Core);
955 Assert(fInserted); NOREF(fInserted);
956
957 /* Add to the dirty list. */
958 pdmBlkCacheAddDirtyEntry(pBlkCache, pEntry);
959 pdmBlkCacheEntryAddToList(&pBlkCacheGlobal->LruRecentlyUsedIn, pEntry);
960 pdmBlkCacheAdd(pBlkCacheGlobal, cbEntry);
961 pdmBlkCacheEntryRelease(pEntry);
962 cEntries--;
963 }
964
965 cRefs--;
966 }
967
968 if (pszId)
969 RTMemFree(pszId);
970
971 if (cRefs && RT_SUCCESS(rc))
972 rc = SSMR3SetCfgError(pSSM, RT_SRC_POS,
973 N_("Unexpected error while restoring state. Please make sure the source and target VMs have compatible storage configurations"));
974
975 pdmBlkCacheLockLeave(pBlkCacheGlobal);
976
977 if (RT_SUCCESS(rc))
978 {
979 uint32_t u32 = 0;
980 rc = SSMR3GetU32(pSSM, &u32);
981 if (RT_SUCCESS(rc))
982 AssertMsgReturn(u32 == UINT32_MAX, ("%#x\n", u32), VERR_SSM_DATA_UNIT_FORMAT_CHANGED);
983 }
984
985 return rc;
986}
987
988int pdmR3BlkCacheInit(PVM pVM)
989{
990 int rc = VINF_SUCCESS;
991 PUVM pUVM = pVM->pUVM;
992 PPDMBLKCACHEGLOBAL pBlkCacheGlobal;
993
994 LogFlowFunc((": pVM=%p\n", pVM));
995
996 VM_ASSERT_EMT(pVM);
997
998 PCFGMNODE pCfgRoot = CFGMR3GetRoot(pVM);
999 PCFGMNODE pCfgBlkCache = CFGMR3GetChild(CFGMR3GetChild(pCfgRoot, "PDM"), "BlkCache");
1000
1001 pBlkCacheGlobal = (PPDMBLKCACHEGLOBAL)RTMemAllocZ(sizeof(PDMBLKCACHEGLOBAL));
1002 if (!pBlkCacheGlobal)
1003 return VERR_NO_MEMORY;
1004
1005 RTListInit(&pBlkCacheGlobal->ListUsers);
1006 pBlkCacheGlobal->pVM = pVM;
1007 pBlkCacheGlobal->cRefs = 0;
1008 pBlkCacheGlobal->cbCached = 0;
1009 pBlkCacheGlobal->fCommitInProgress = false;
1010
1011 /* Initialize members */
1012 pBlkCacheGlobal->LruRecentlyUsedIn.pHead = NULL;
1013 pBlkCacheGlobal->LruRecentlyUsedIn.pTail = NULL;
1014 pBlkCacheGlobal->LruRecentlyUsedIn.cbCached = 0;
1015
1016 pBlkCacheGlobal->LruRecentlyUsedOut.pHead = NULL;
1017 pBlkCacheGlobal->LruRecentlyUsedOut.pTail = NULL;
1018 pBlkCacheGlobal->LruRecentlyUsedOut.cbCached = 0;
1019
1020 pBlkCacheGlobal->LruFrequentlyUsed.pHead = NULL;
1021 pBlkCacheGlobal->LruFrequentlyUsed.pTail = NULL;
1022 pBlkCacheGlobal->LruFrequentlyUsed.cbCached = 0;
1023
1024 do
1025 {
1026 rc = CFGMR3QueryU32Def(pCfgBlkCache, "CacheSize", &pBlkCacheGlobal->cbMax, 5 * _1M);
1027 AssertLogRelRCBreak(rc);
1028 LogFlowFunc(("Maximum number of bytes cached %u\n", pBlkCacheGlobal->cbMax));
1029
1030 pBlkCacheGlobal->cbRecentlyUsedInMax = (pBlkCacheGlobal->cbMax / 100) * 25; /* 25% of the buffer size */
1031 pBlkCacheGlobal->cbRecentlyUsedOutMax = (pBlkCacheGlobal->cbMax / 100) * 50; /* 50% of the buffer size */
1032 LogFlowFunc(("cbRecentlyUsedInMax=%u cbRecentlyUsedOutMax=%u\n",
1033 pBlkCacheGlobal->cbRecentlyUsedInMax, pBlkCacheGlobal->cbRecentlyUsedOutMax));
1034
1035 /** @todo r=aeichner: Experiment to find optimal default values */
1036 rc = CFGMR3QueryU32Def(pCfgBlkCache, "CacheCommitIntervalMs", &pBlkCacheGlobal->u32CommitTimeoutMs, 10000 /* 10sec */);
1037 AssertLogRelRCBreak(rc);
1038 rc = CFGMR3QueryU32Def(pCfgBlkCache, "CacheCommitThreshold", &pBlkCacheGlobal->cbCommitDirtyThreshold, pBlkCacheGlobal->cbMax / 2);
1039 AssertLogRelRCBreak(rc);
1040 } while (0);
1041
1042 if (RT_SUCCESS(rc))
1043 {
1044 STAMR3Register(pVM, &pBlkCacheGlobal->cbMax,
1045 STAMTYPE_U32, STAMVISIBILITY_ALWAYS,
1046 "/PDM/BlkCache/cbMax",
1047 STAMUNIT_BYTES,
1048 "Maximum cache size");
1049 STAMR3Register(pVM, &pBlkCacheGlobal->cbCached,
1050 STAMTYPE_U32, STAMVISIBILITY_ALWAYS,
1051 "/PDM/BlkCache/cbCached",
1052 STAMUNIT_BYTES,
1053 "Currently used cache");
1054 STAMR3Register(pVM, &pBlkCacheGlobal->LruRecentlyUsedIn.cbCached,
1055 STAMTYPE_U32, STAMVISIBILITY_ALWAYS,
1056 "/PDM/BlkCache/cbCachedMruIn",
1057 STAMUNIT_BYTES,
1058 "Number of bytes cached in MRU list");
1059 STAMR3Register(pVM, &pBlkCacheGlobal->LruRecentlyUsedOut.cbCached,
1060 STAMTYPE_U32, STAMVISIBILITY_ALWAYS,
1061 "/PDM/BlkCache/cbCachedMruOut",
1062 STAMUNIT_BYTES,
1063 "Number of bytes cached in FRU list");
1064 STAMR3Register(pVM, &pBlkCacheGlobal->LruFrequentlyUsed.cbCached,
1065 STAMTYPE_U32, STAMVISIBILITY_ALWAYS,
1066 "/PDM/BlkCache/cbCachedFru",
1067 STAMUNIT_BYTES,
1068 "Number of bytes cached in FRU ghost list");
1069
1070#ifdef VBOX_WITH_STATISTICS
1071 STAMR3Register(pVM, &pBlkCacheGlobal->cHits,
1072 STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS,
1073 "/PDM/BlkCache/CacheHits",
1074 STAMUNIT_COUNT, "Number of hits in the cache");
1075 STAMR3Register(pVM, &pBlkCacheGlobal->cPartialHits,
1076 STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS,
1077 "/PDM/BlkCache/CachePartialHits",
1078 STAMUNIT_COUNT, "Number of partial hits in the cache");
1079 STAMR3Register(pVM, &pBlkCacheGlobal->cMisses,
1080 STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS,
1081 "/PDM/BlkCache/CacheMisses",
1082 STAMUNIT_COUNT, "Number of misses when accessing the cache");
1083 STAMR3Register(pVM, &pBlkCacheGlobal->StatRead,
1084 STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS,
1085 "/PDM/BlkCache/CacheRead",
1086 STAMUNIT_BYTES, "Number of bytes read from the cache");
1087 STAMR3Register(pVM, &pBlkCacheGlobal->StatWritten,
1088 STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS,
1089 "/PDM/BlkCache/CacheWritten",
1090 STAMUNIT_BYTES, "Number of bytes written to the cache");
1091 STAMR3Register(pVM, &pBlkCacheGlobal->StatTreeGet,
1092 STAMTYPE_PROFILE_ADV, STAMVISIBILITY_ALWAYS,
1093 "/PDM/BlkCache/CacheTreeGet",
1094 STAMUNIT_TICKS_PER_CALL, "Time taken to access an entry in the tree");
1095 STAMR3Register(pVM, &pBlkCacheGlobal->StatTreeInsert,
1096 STAMTYPE_PROFILE_ADV, STAMVISIBILITY_ALWAYS,
1097 "/PDM/BlkCache/CacheTreeInsert",
1098 STAMUNIT_TICKS_PER_CALL, "Time taken to insert an entry in the tree");
1099 STAMR3Register(pVM, &pBlkCacheGlobal->StatTreeRemove,
1100 STAMTYPE_PROFILE_ADV, STAMVISIBILITY_ALWAYS,
1101 "/PDM/BlkCache/CacheTreeRemove",
1102 STAMUNIT_TICKS_PER_CALL, "Time taken to remove an entry an the tree");
1103 STAMR3Register(pVM, &pBlkCacheGlobal->StatBuffersReused,
1104 STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS,
1105 "/PDM/BlkCache/CacheBuffersReused",
1106 STAMUNIT_COUNT, "Number of times a buffer could be reused");
1107#endif
1108
1109 /* Initialize the critical section */
1110 rc = RTCritSectInit(&pBlkCacheGlobal->CritSect);
1111 }
1112
1113 if (RT_SUCCESS(rc))
1114 {
1115 /* Create the commit timer */
1116 if (pBlkCacheGlobal->u32CommitTimeoutMs > 0)
1117 rc = TMR3TimerCreateInternal(pVM, TMCLOCK_REAL,
1118 pdmBlkCacheCommitTimerCallback,
1119 pBlkCacheGlobal,
1120 "BlkCache-Commit",
1121 &pBlkCacheGlobal->pTimerCommit);
1122
1123 if (RT_SUCCESS(rc))
1124 {
1125 /* Register saved state handler. */
1126 rc = SSMR3RegisterInternal(pVM, "pdmblkcache", 0, PDM_BLK_CACHE_SAVED_STATE_VERSION, pBlkCacheGlobal->cbMax,
1127 NULL, NULL, NULL,
1128 NULL, pdmR3BlkCacheSaveExec, NULL,
1129 NULL, pdmR3BlkCacheLoadExec, NULL);
1130 if (RT_SUCCESS(rc))
1131 {
1132 LogRel(("BlkCache: Cache successfully initialized. Cache size is %u bytes\n", pBlkCacheGlobal->cbMax));
1133 LogRel(("BlkCache: Cache commit interval is %u ms\n", pBlkCacheGlobal->u32CommitTimeoutMs));
1134 LogRel(("BlkCache: Cache commit threshold is %u bytes\n", pBlkCacheGlobal->cbCommitDirtyThreshold));
1135 pUVM->pdm.s.pBlkCacheGlobal = pBlkCacheGlobal;
1136 return VINF_SUCCESS;
1137 }
1138 }
1139
1140 RTCritSectDelete(&pBlkCacheGlobal->CritSect);
1141 }
1142
1143 if (pBlkCacheGlobal)
1144 RTMemFree(pBlkCacheGlobal);
1145
1146 LogFlowFunc((": returns rc=%Rrc\n", pVM, rc));
1147 return rc;
1148}
1149
1150void pdmR3BlkCacheTerm(PVM pVM)
1151{
1152 PPDMBLKCACHEGLOBAL pBlkCacheGlobal = pVM->pUVM->pdm.s.pBlkCacheGlobal;
1153
1154 if (pBlkCacheGlobal)
1155 {
1156 /* Make sure no one else uses the cache now */
1157 pdmBlkCacheLockEnter(pBlkCacheGlobal);
1158
1159 /* Cleanup deleting all cache entries waiting for in progress entries to finish. */
1160 pdmBlkCacheDestroyList(&pBlkCacheGlobal->LruRecentlyUsedIn);
1161 pdmBlkCacheDestroyList(&pBlkCacheGlobal->LruRecentlyUsedOut);
1162 pdmBlkCacheDestroyList(&pBlkCacheGlobal->LruFrequentlyUsed);
1163
1164 pdmBlkCacheLockLeave(pBlkCacheGlobal);
1165
1166 RTCritSectDelete(&pBlkCacheGlobal->CritSect);
1167 RTMemFree(pBlkCacheGlobal);
1168 pVM->pUVM->pdm.s.pBlkCacheGlobal = NULL;
1169 }
1170}
1171
1172int pdmR3BlkCacheResume(PVM pVM)
1173{
1174 PPDMBLKCACHEGLOBAL pBlkCacheGlobal = pVM->pUVM->pdm.s.pBlkCacheGlobal;
1175
1176 LogFlowFunc(("pVM=%#p\n", pVM));
1177
1178 if ( pBlkCacheGlobal
1179 && ASMAtomicXchgBool(&pBlkCacheGlobal->fIoErrorVmSuspended, false))
1180 {
1181 /* The VM was suspended because of an I/O error, commit all dirty entries. */
1182 pdmBlkCacheCommitDirtyEntries(pBlkCacheGlobal);
1183 }
1184
1185 return VINF_SUCCESS;
1186}
1187
1188static int pdmR3BlkCacheRetain(PVM pVM, PPPDMBLKCACHE ppBlkCache, const char *pcszId)
1189{
1190 int rc = VINF_SUCCESS;
1191 PPDMBLKCACHE pBlkCache = NULL;
1192 PPDMBLKCACHEGLOBAL pBlkCacheGlobal = pVM->pUVM->pdm.s.pBlkCacheGlobal;
1193
1194 if (!pBlkCacheGlobal)
1195 return VERR_NOT_SUPPORTED;
1196
1197 /*
1198 * Check that no other user cache has the same id first,
1199 * Unique id's are necessary in case the state is saved.
1200 */
1201 pdmBlkCacheLockEnter(pBlkCacheGlobal);
1202
1203 pBlkCache = pdmR3BlkCacheFindById(pBlkCacheGlobal, pcszId);
1204
1205 if (!pBlkCache)
1206 {
1207 pBlkCache = (PPDMBLKCACHE)RTMemAllocZ(sizeof(PDMBLKCACHE));
1208
1209 if (pBlkCache)
1210 pBlkCache->pszId = RTStrDup(pcszId);
1211
1212 if ( pBlkCache
1213 && pBlkCache->pszId)
1214 {
1215 pBlkCache->fSuspended = false;
1216 pBlkCache->pCache = pBlkCacheGlobal;
1217 RTListInit(&pBlkCache->ListDirtyNotCommitted);
1218
1219 rc = RTSpinlockCreate(&pBlkCache->LockList, RTSPINLOCK_FLAGS_INTERRUPT_UNSAFE, "pdmR3BlkCacheRetain");
1220 if (RT_SUCCESS(rc))
1221 {
1222 rc = RTSemRWCreate(&pBlkCache->SemRWEntries);
1223 if (RT_SUCCESS(rc))
1224 {
1225 pBlkCache->pTree = (PAVLRU64TREE)RTMemAllocZ(sizeof(AVLRFOFFTREE));
1226 if (pBlkCache->pTree)
1227 {
1228#ifdef VBOX_WITH_STATISTICS
1229 STAMR3RegisterF(pBlkCacheGlobal->pVM, &pBlkCache->StatWriteDeferred,
1230 STAMTYPE_COUNTER, STAMVISIBILITY_ALWAYS,
1231 STAMUNIT_COUNT, "Number of deferred writes",
1232 "/PDM/BlkCache/%s/Cache/DeferredWrites", pBlkCache->pszId);
1233#endif
1234
1235 /* Add to the list of users. */
1236 pBlkCacheGlobal->cRefs++;
1237 RTListAppend(&pBlkCacheGlobal->ListUsers, &pBlkCache->NodeCacheUser);
1238 pdmBlkCacheLockLeave(pBlkCacheGlobal);
1239
1240 *ppBlkCache = pBlkCache;
1241 LogFlowFunc(("returns success\n"));
1242 return VINF_SUCCESS;
1243 }
1244
1245 rc = VERR_NO_MEMORY;
1246 RTSemRWDestroy(pBlkCache->SemRWEntries);
1247 }
1248
1249 RTSpinlockDestroy(pBlkCache->LockList);
1250 }
1251
1252 RTStrFree(pBlkCache->pszId);
1253 }
1254 else
1255 rc = VERR_NO_MEMORY;
1256
1257 if (pBlkCache)
1258 RTMemFree(pBlkCache);
1259 }
1260 else
1261 rc = VERR_ALREADY_EXISTS;
1262
1263 pdmBlkCacheLockLeave(pBlkCacheGlobal);
1264
1265 LogFlowFunc(("Leave rc=%Rrc\n", rc));
1266 return rc;
1267}
1268
1269VMMR3DECL(int) PDMR3BlkCacheRetainDriver(PVM pVM, PPDMDRVINS pDrvIns, PPPDMBLKCACHE ppBlkCache,
1270 PFNPDMBLKCACHEXFERCOMPLETEDRV pfnXferComplete,
1271 PFNPDMBLKCACHEXFERENQUEUEDRV pfnXferEnqueue,
1272 PFNPDMBLKCACHEXFERENQUEUEDISCARDDRV pfnXferEnqueueDiscard,
1273 const char *pcszId)
1274{
1275 int rc = VINF_SUCCESS;
1276 PPDMBLKCACHE pBlkCache;
1277
1278 rc = pdmR3BlkCacheRetain(pVM, &pBlkCache, pcszId);
1279 if (RT_SUCCESS(rc))
1280 {
1281 pBlkCache->enmType = PDMBLKCACHETYPE_DRV;
1282 pBlkCache->u.Drv.pfnXferComplete = pfnXferComplete;
1283 pBlkCache->u.Drv.pfnXferEnqueue = pfnXferEnqueue;
1284 pBlkCache->u.Drv.pfnXferEnqueueDiscard = pfnXferEnqueueDiscard;
1285 pBlkCache->u.Drv.pDrvIns = pDrvIns;
1286 *ppBlkCache = pBlkCache;
1287 }
1288
1289 LogFlowFunc(("Leave rc=%Rrc\n", rc));
1290 return rc;
1291}
1292
1293VMMR3DECL(int) PDMR3BlkCacheRetainDevice(PVM pVM, PPDMDEVINS pDevIns, PPPDMBLKCACHE ppBlkCache,
1294 PFNPDMBLKCACHEXFERCOMPLETEDEV pfnXferComplete,
1295 PFNPDMBLKCACHEXFERENQUEUEDEV pfnXferEnqueue,
1296 PFNPDMBLKCACHEXFERENQUEUEDISCARDDEV pfnXferEnqueueDiscard,
1297 const char *pcszId)
1298{
1299 int rc = VINF_SUCCESS;
1300 PPDMBLKCACHE pBlkCache;
1301
1302 rc = pdmR3BlkCacheRetain(pVM, &pBlkCache, pcszId);
1303 if (RT_SUCCESS(rc))
1304 {
1305 pBlkCache->enmType = PDMBLKCACHETYPE_DEV;
1306 pBlkCache->u.Dev.pfnXferComplete = pfnXferComplete;
1307 pBlkCache->u.Dev.pfnXferEnqueue = pfnXferEnqueue;
1308 pBlkCache->u.Dev.pfnXferEnqueueDiscard = pfnXferEnqueueDiscard;
1309 pBlkCache->u.Dev.pDevIns = pDevIns;
1310 *ppBlkCache = pBlkCache;
1311 }
1312
1313 LogFlowFunc(("Leave rc=%Rrc\n", rc));
1314 return rc;
1315
1316}
1317
1318VMMR3DECL(int) PDMR3BlkCacheRetainUsb(PVM pVM, PPDMUSBINS pUsbIns, PPPDMBLKCACHE ppBlkCache,
1319 PFNPDMBLKCACHEXFERCOMPLETEUSB pfnXferComplete,
1320 PFNPDMBLKCACHEXFERENQUEUEUSB pfnXferEnqueue,
1321 PFNPDMBLKCACHEXFERENQUEUEDISCARDUSB pfnXferEnqueueDiscard,
1322 const char *pcszId)
1323{
1324 int rc = VINF_SUCCESS;
1325 PPDMBLKCACHE pBlkCache;
1326
1327 rc = pdmR3BlkCacheRetain(pVM, &pBlkCache, pcszId);
1328 if (RT_SUCCESS(rc))
1329 {
1330 pBlkCache->enmType = PDMBLKCACHETYPE_USB;
1331 pBlkCache->u.Usb.pfnXferComplete = pfnXferComplete;
1332 pBlkCache->u.Usb.pfnXferEnqueue = pfnXferEnqueue;
1333 pBlkCache->u.Usb.pfnXferEnqueueDiscard = pfnXferEnqueueDiscard;
1334 pBlkCache->u.Usb.pUsbIns = pUsbIns;
1335 *ppBlkCache = pBlkCache;
1336 }
1337
1338 LogFlowFunc(("Leave rc=%Rrc\n", rc));
1339 return rc;
1340
1341}
1342
1343VMMR3DECL(int) PDMR3BlkCacheRetainInt(PVM pVM, void *pvUser, PPPDMBLKCACHE ppBlkCache,
1344 PFNPDMBLKCACHEXFERCOMPLETEINT pfnXferComplete,
1345 PFNPDMBLKCACHEXFERENQUEUEINT pfnXferEnqueue,
1346 PFNPDMBLKCACHEXFERENQUEUEDISCARDINT pfnXferEnqueueDiscard,
1347 const char *pcszId)
1348{
1349 int rc = VINF_SUCCESS;
1350 PPDMBLKCACHE pBlkCache;
1351
1352 rc = pdmR3BlkCacheRetain(pVM, &pBlkCache, pcszId);
1353 if (RT_SUCCESS(rc))
1354 {
1355 pBlkCache->enmType = PDMBLKCACHETYPE_INTERNAL;
1356 pBlkCache->u.Int.pfnXferComplete = pfnXferComplete;
1357 pBlkCache->u.Int.pfnXferEnqueue = pfnXferEnqueue;
1358 pBlkCache->u.Int.pfnXferEnqueueDiscard = pfnXferEnqueueDiscard;
1359 pBlkCache->u.Int.pvUser = pvUser;
1360 *ppBlkCache = pBlkCache;
1361 }
1362
1363 LogFlowFunc(("Leave rc=%Rrc\n", rc));
1364 return rc;
1365
1366}
1367
1368/**
1369 * Callback for the AVL destroy routine. Frees a cache entry for this endpoint.
1370 *
1371 * @returns IPRT status code.
1372 * @param pNode The node to destroy.
1373 * @param pvUser Opaque user data.
1374 */
1375static int pdmBlkCacheEntryDestroy(PAVLRU64NODECORE pNode, void *pvUser)
1376{
1377 PPDMBLKCACHEENTRY pEntry = (PPDMBLKCACHEENTRY)pNode;
1378 PPDMBLKCACHEGLOBAL pCache = (PPDMBLKCACHEGLOBAL)pvUser;
1379 PPDMBLKCACHE pBlkCache = pEntry->pBlkCache;
1380
1381 while (ASMAtomicReadU32(&pEntry->fFlags) & PDMBLKCACHE_ENTRY_IO_IN_PROGRESS)
1382 {
1383 /* Leave the locks to let the I/O thread make progress but reference the entry to prevent eviction. */
1384 pdmBlkCacheEntryRef(pEntry);
1385 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
1386 pdmBlkCacheLockLeave(pCache);
1387
1388 RTThreadSleep(250);
1389
1390 /* Re-enter all locks */
1391 pdmBlkCacheLockEnter(pCache);
1392 RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
1393 pdmBlkCacheEntryRelease(pEntry);
1394 }
1395
1396 AssertMsg(!(pEntry->fFlags & PDMBLKCACHE_ENTRY_IO_IN_PROGRESS),
1397 ("Entry is dirty and/or still in progress fFlags=%#x\n", pEntry->fFlags));
1398
1399 bool fUpdateCache = pEntry->pList == &pCache->LruFrequentlyUsed
1400 || pEntry->pList == &pCache->LruRecentlyUsedIn;
1401
1402 pdmBlkCacheEntryRemoveFromList(pEntry);
1403
1404 if (fUpdateCache)
1405 pdmBlkCacheSub(pCache, pEntry->cbData);
1406
1407 RTMemPageFree(pEntry->pbData, pEntry->cbData);
1408 RTMemFree(pEntry);
1409
1410 return VINF_SUCCESS;
1411}
1412
1413/**
1414 * Destroys all cache resources used by the given endpoint.
1415 *
1416 * @returns nothing.
1417 * @param pEndpoint The endpoint to the destroy.
1418 */
1419VMMR3DECL(void) PDMR3BlkCacheRelease(PPDMBLKCACHE pBlkCache)
1420{
1421 PPDMBLKCACHEGLOBAL pCache = pBlkCache->pCache;
1422
1423 /*
1424 * Commit all dirty entries now (they are waited on for completion during the
1425 * destruction of the AVL tree below).
1426 * The exception is if the VM was paused because of an I/O error before.
1427 */
1428 if (!ASMAtomicReadBool(&pCache->fIoErrorVmSuspended))
1429 pdmBlkCacheCommit(pBlkCache);
1430
1431 /* Make sure nobody is accessing the cache while we delete the tree. */
1432 pdmBlkCacheLockEnter(pCache);
1433 RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
1434 RTAvlrU64Destroy(pBlkCache->pTree, pdmBlkCacheEntryDestroy, pCache);
1435 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
1436
1437 RTSpinlockDestroy(pBlkCache->LockList);
1438
1439 pCache->cRefs--;
1440 RTListNodeRemove(&pBlkCache->NodeCacheUser);
1441
1442 pdmBlkCacheLockLeave(pCache);
1443
1444 RTSemRWDestroy(pBlkCache->SemRWEntries);
1445
1446#ifdef VBOX_WITH_STATISTICS
1447 STAMR3DeregisterF(pCache->pVM->pUVM, "/PDM/BlkCache/%s/Cache/DeferredWrites", pBlkCache->pszId);
1448#endif
1449
1450 RTStrFree(pBlkCache->pszId);
1451 RTMemFree(pBlkCache);
1452}
1453
1454VMMR3DECL(void) PDMR3BlkCacheReleaseDevice(PVM pVM, PPDMDEVINS pDevIns)
1455{
1456 LogFlow(("%s: pDevIns=%p\n", __FUNCTION__, pDevIns));
1457
1458 /*
1459 * Validate input.
1460 */
1461 if (!pDevIns)
1462 return;
1463 VM_ASSERT_EMT(pVM);
1464
1465 PPDMBLKCACHEGLOBAL pBlkCacheGlobal = pVM->pUVM->pdm.s.pBlkCacheGlobal;
1466 PPDMBLKCACHE pBlkCache, pBlkCacheNext;
1467
1468 /* Return silently if not supported. */
1469 if (!pBlkCacheGlobal)
1470 return;
1471
1472 pdmBlkCacheLockEnter(pBlkCacheGlobal);
1473
1474 RTListForEachSafe(&pBlkCacheGlobal->ListUsers, pBlkCache, pBlkCacheNext, PDMBLKCACHE, NodeCacheUser)
1475 {
1476 if ( pBlkCache->enmType == PDMBLKCACHETYPE_DEV
1477 && pBlkCache->u.Dev.pDevIns == pDevIns)
1478 PDMR3BlkCacheRelease(pBlkCache);
1479 }
1480
1481 pdmBlkCacheLockLeave(pBlkCacheGlobal);
1482}
1483
1484VMMR3DECL(void) PDMR3BlkCacheReleaseDriver(PVM pVM, PPDMDRVINS pDrvIns)
1485{
1486 LogFlow(("%s: pDrvIns=%p\n", __FUNCTION__, pDrvIns));
1487
1488 /*
1489 * Validate input.
1490 */
1491 if (!pDrvIns)
1492 return;
1493 VM_ASSERT_EMT(pVM);
1494
1495 PPDMBLKCACHEGLOBAL pBlkCacheGlobal = pVM->pUVM->pdm.s.pBlkCacheGlobal;
1496 PPDMBLKCACHE pBlkCache, pBlkCacheNext;
1497
1498 /* Return silently if not supported. */
1499 if (!pBlkCacheGlobal)
1500 return;
1501
1502 pdmBlkCacheLockEnter(pBlkCacheGlobal);
1503
1504 RTListForEachSafe(&pBlkCacheGlobal->ListUsers, pBlkCache, pBlkCacheNext, PDMBLKCACHE, NodeCacheUser)
1505 {
1506 if ( pBlkCache->enmType == PDMBLKCACHETYPE_DRV
1507 && pBlkCache->u.Drv.pDrvIns == pDrvIns)
1508 PDMR3BlkCacheRelease(pBlkCache);
1509 }
1510
1511 pdmBlkCacheLockLeave(pBlkCacheGlobal);
1512}
1513
1514VMMR3DECL(void) PDMR3BlkCacheReleaseUsb(PVM pVM, PPDMUSBINS pUsbIns)
1515{
1516 LogFlow(("%s: pUsbIns=%p\n", __FUNCTION__, pUsbIns));
1517
1518 /*
1519 * Validate input.
1520 */
1521 if (!pUsbIns)
1522 return;
1523 VM_ASSERT_EMT(pVM);
1524
1525 PPDMBLKCACHEGLOBAL pBlkCacheGlobal = pVM->pUVM->pdm.s.pBlkCacheGlobal;
1526 PPDMBLKCACHE pBlkCache, pBlkCacheNext;
1527
1528 /* Return silently if not supported. */
1529 if (!pBlkCacheGlobal)
1530 return;
1531
1532 pdmBlkCacheLockEnter(pBlkCacheGlobal);
1533
1534 RTListForEachSafe(&pBlkCacheGlobal->ListUsers, pBlkCache, pBlkCacheNext, PDMBLKCACHE, NodeCacheUser)
1535 {
1536 if ( pBlkCache->enmType == PDMBLKCACHETYPE_USB
1537 && pBlkCache->u.Usb.pUsbIns == pUsbIns)
1538 PDMR3BlkCacheRelease(pBlkCache);
1539 }
1540
1541 pdmBlkCacheLockLeave(pBlkCacheGlobal);
1542}
1543
1544static PPDMBLKCACHEENTRY pdmBlkCacheGetCacheEntryByOffset(PPDMBLKCACHE pBlkCache, uint64_t off)
1545{
1546 STAM_PROFILE_ADV_START(&pBlkCache->pCache->StatTreeGet, Cache);
1547
1548 RTSemRWRequestRead(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
1549 PPDMBLKCACHEENTRY pEntry = (PPDMBLKCACHEENTRY)RTAvlrU64RangeGet(pBlkCache->pTree, off);
1550 if (pEntry)
1551 pdmBlkCacheEntryRef(pEntry);
1552 RTSemRWReleaseRead(pBlkCache->SemRWEntries);
1553
1554 STAM_PROFILE_ADV_STOP(&pBlkCache->pCache->StatTreeGet, Cache);
1555
1556 return pEntry;
1557}
1558
1559/**
1560 * Return the best fit cache entries for the given offset.
1561 *
1562 * @returns nothing.
1563 * @param pBlkCache The endpoint cache.
1564 * @param off The offset.
1565 * @param pEntryAbove Where to store the pointer to the best fit entry above the
1566 * the given offset. NULL if not required.
1567 */
1568static void pdmBlkCacheGetCacheBestFitEntryByOffset(PPDMBLKCACHE pBlkCache, uint64_t off,
1569 PPDMBLKCACHEENTRY *ppEntryAbove)
1570{
1571 STAM_PROFILE_ADV_START(&pBlkCache->pCache->StatTreeGet, Cache);
1572
1573 RTSemRWRequestRead(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
1574 if (ppEntryAbove)
1575 {
1576 *ppEntryAbove = (PPDMBLKCACHEENTRY)RTAvlrU64GetBestFit(pBlkCache->pTree, off, true /*fAbove*/);
1577 if (*ppEntryAbove)
1578 pdmBlkCacheEntryRef(*ppEntryAbove);
1579 }
1580
1581 RTSemRWReleaseRead(pBlkCache->SemRWEntries);
1582
1583 STAM_PROFILE_ADV_STOP(&pBlkCache->pCache->StatTreeGet, Cache);
1584}
1585
1586static void pdmBlkCacheInsertEntry(PPDMBLKCACHE pBlkCache, PPDMBLKCACHEENTRY pEntry)
1587{
1588 STAM_PROFILE_ADV_START(&pBlkCache->pCache->StatTreeInsert, Cache);
1589 RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
1590 bool fInserted = RTAvlrU64Insert(pBlkCache->pTree, &pEntry->Core);
1591 AssertMsg(fInserted, ("Node was not inserted into tree\n")); NOREF(fInserted);
1592 STAM_PROFILE_ADV_STOP(&pBlkCache->pCache->StatTreeInsert, Cache);
1593 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
1594}
1595
1596/**
1597 * Allocates and initializes a new entry for the cache.
1598 * The entry has a reference count of 1.
1599 *
1600 * @returns Pointer to the new cache entry or NULL if out of memory.
1601 * @param pBlkCache The cache the entry belongs to.
1602 * @param off Start offset.
1603 * @param cbData Size of the cache entry.
1604 * @param pbBuffer Pointer to the buffer to use.
1605 * NULL if a new buffer should be allocated.
1606 * The buffer needs to have the same size of the entry.
1607 */
1608static PPDMBLKCACHEENTRY pdmBlkCacheEntryAlloc(PPDMBLKCACHE pBlkCache,
1609 uint64_t off, size_t cbData, uint8_t *pbBuffer)
1610{
1611 AssertReturn(cbData <= UINT32_MAX, NULL);
1612 PPDMBLKCACHEENTRY pEntryNew = (PPDMBLKCACHEENTRY)RTMemAllocZ(sizeof(PDMBLKCACHEENTRY));
1613
1614 if (RT_UNLIKELY(!pEntryNew))
1615 return NULL;
1616
1617 pEntryNew->Core.Key = off;
1618 pEntryNew->Core.KeyLast = off + cbData - 1;
1619 pEntryNew->pBlkCache = pBlkCache;
1620 pEntryNew->fFlags = 0;
1621 pEntryNew->cRefs = 1; /* We are using it now. */
1622 pEntryNew->pList = NULL;
1623 pEntryNew->cbData = (uint32_t)cbData;
1624 pEntryNew->pWaitingHead = NULL;
1625 pEntryNew->pWaitingTail = NULL;
1626 if (pbBuffer)
1627 pEntryNew->pbData = pbBuffer;
1628 else
1629 pEntryNew->pbData = (uint8_t *)RTMemPageAlloc(cbData);
1630
1631 if (RT_UNLIKELY(!pEntryNew->pbData))
1632 {
1633 RTMemFree(pEntryNew);
1634 return NULL;
1635 }
1636
1637 return pEntryNew;
1638}
1639
1640/**
1641 * Checks that a set of flags is set/clear acquiring the R/W semaphore
1642 * in exclusive mode.
1643 *
1644 * @returns true if the flag in fSet is set and the one in fClear is clear.
1645 * false otherwise.
1646 * The R/W semaphore is only held if true is returned.
1647 *
1648 * @param pBlkCache The endpoint cache instance data.
1649 * @param pEntry The entry to check the flags for.
1650 * @param fSet The flag which is tested to be set.
1651 * @param fClear The flag which is tested to be clear.
1652 */
1653DECLINLINE(bool) pdmBlkCacheEntryFlagIsSetClearAcquireLock(PPDMBLKCACHE pBlkCache,
1654 PPDMBLKCACHEENTRY pEntry,
1655 uint32_t fSet, uint32_t fClear)
1656{
1657 uint32_t fFlags = ASMAtomicReadU32(&pEntry->fFlags);
1658 bool fPassed = ((fFlags & fSet) && !(fFlags & fClear));
1659
1660 if (fPassed)
1661 {
1662 /* Acquire the lock and check again because the completion callback might have raced us. */
1663 RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
1664
1665 fFlags = ASMAtomicReadU32(&pEntry->fFlags);
1666 fPassed = ((fFlags & fSet) && !(fFlags & fClear));
1667
1668 /* Drop the lock if we didn't passed the test. */
1669 if (!fPassed)
1670 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
1671 }
1672
1673 return fPassed;
1674}
1675
1676/**
1677 * Adds a segment to the waiting list for a cache entry
1678 * which is currently in progress.
1679 *
1680 * @returns nothing.
1681 * @param pEntry The cache entry to add the segment to.
1682 * @param pSeg The segment to add.
1683 */
1684DECLINLINE(void) pdmBlkCacheEntryAddWaiter(PPDMBLKCACHEENTRY pEntry,
1685 PPDMBLKCACHEWAITER pWaiter)
1686{
1687 pWaiter->pNext = NULL;
1688
1689 if (pEntry->pWaitingHead)
1690 {
1691 AssertPtr(pEntry->pWaitingTail);
1692
1693 pEntry->pWaitingTail->pNext = pWaiter;
1694 pEntry->pWaitingTail = pWaiter;
1695 }
1696 else
1697 {
1698 Assert(!pEntry->pWaitingTail);
1699
1700 pEntry->pWaitingHead = pWaiter;
1701 pEntry->pWaitingTail = pWaiter;
1702 }
1703}
1704
1705/**
1706 * Add a buffer described by the I/O memory context
1707 * to the entry waiting for completion.
1708 *
1709 * @returns VBox status code.
1710 * @param pEntry The entry to add the buffer to.
1711 * @param pTask Task associated with the buffer.
1712 * @param pIoMemCtx The memory context to use.
1713 * @param offDiff Offset from the start of the buffer
1714 * in the entry.
1715 * @param cbData Amount of data to wait for onthis entry.
1716 * @param fWrite Flag whether the task waits because it wants to write
1717 * to the cache entry.
1718 */
1719static int pdmBlkCacheEntryWaitersAdd(PPDMBLKCACHEENTRY pEntry,
1720 PPDMBLKCACHEREQ pReq,
1721 PRTSGBUF pSgBuf, uint64_t offDiff,
1722 size_t cbData, bool fWrite)
1723{
1724 PPDMBLKCACHEWAITER pWaiter = (PPDMBLKCACHEWAITER)RTMemAllocZ(sizeof(PDMBLKCACHEWAITER));
1725 if (!pWaiter)
1726 return VERR_NO_MEMORY;
1727
1728 ASMAtomicIncU32(&pReq->cXfersPending);
1729 pWaiter->pReq = pReq;
1730 pWaiter->offCacheEntry = offDiff;
1731 pWaiter->cbTransfer = cbData;
1732 pWaiter->fWrite = fWrite;
1733 RTSgBufClone(&pWaiter->SgBuf, pSgBuf);
1734 RTSgBufAdvance(pSgBuf, cbData);
1735
1736 pdmBlkCacheEntryAddWaiter(pEntry, pWaiter);
1737
1738 return VINF_SUCCESS;
1739}
1740
1741/**
1742 * Calculate aligned offset and size for a new cache entry which do not
1743 * intersect with an already existing entry and the file end.
1744 *
1745 * @returns The number of bytes the entry can hold of the requested amount
1746 * of bytes.
1747 * @param pEndpoint The endpoint.
1748 * @param pBlkCache The endpoint cache.
1749 * @param off The start offset.
1750 * @param cb The number of bytes the entry needs to hold at
1751 * least.
1752 * @param pcbEntry Where to store the number of bytes the entry can hold.
1753 * Can be less than given because of other entries.
1754 */
1755static uint32_t pdmBlkCacheEntryBoundariesCalc(PPDMBLKCACHE pBlkCache,
1756 uint64_t off, uint32_t cb,
1757 uint32_t *pcbEntry)
1758{
1759 /* Get the best fit entries around the offset */
1760 PPDMBLKCACHEENTRY pEntryAbove = NULL;
1761 pdmBlkCacheGetCacheBestFitEntryByOffset(pBlkCache, off, &pEntryAbove);
1762
1763 /* Log the info */
1764 LogFlow(("%sest fit entry above off=%llu (BestFit=%llu BestFitEnd=%llu BestFitSize=%u)\n",
1765 pEntryAbove ? "B" : "No b",
1766 off,
1767 pEntryAbove ? pEntryAbove->Core.Key : 0,
1768 pEntryAbove ? pEntryAbove->Core.KeyLast : 0,
1769 pEntryAbove ? pEntryAbove->cbData : 0));
1770
1771 uint32_t cbNext;
1772 uint32_t cbInEntry;
1773 if ( pEntryAbove
1774 && off + cb > pEntryAbove->Core.Key)
1775 {
1776 cbInEntry = (uint32_t)(pEntryAbove->Core.Key - off);
1777 cbNext = (uint32_t)(pEntryAbove->Core.Key - off);
1778 }
1779 else
1780 {
1781 cbInEntry = cb;
1782 cbNext = cb;
1783 }
1784
1785 /* A few sanity checks */
1786 AssertMsg(!pEntryAbove || off + cbNext <= pEntryAbove->Core.Key,
1787 ("Aligned size intersects with another cache entry\n"));
1788 Assert(cbInEntry <= cbNext);
1789
1790 if (pEntryAbove)
1791 pdmBlkCacheEntryRelease(pEntryAbove);
1792
1793 LogFlow(("off=%llu cbNext=%u\n", off, cbNext));
1794
1795 *pcbEntry = cbNext;
1796
1797 return cbInEntry;
1798}
1799
1800/**
1801 * Create a new cache entry evicting data from the cache if required.
1802 *
1803 * @returns Pointer to the new cache entry or NULL
1804 * if not enough bytes could be evicted from the cache.
1805 * @param pEndpoint The endpoint.
1806 * @param pBlkCache The endpoint cache.
1807 * @param off The offset.
1808 * @param cb Number of bytes the cache entry should have.
1809 * @param pcbData Where to store the number of bytes the new
1810 * entry can hold. May be lower than actually requested
1811 * due to another entry intersecting the access range.
1812 */
1813static PPDMBLKCACHEENTRY pdmBlkCacheEntryCreate(PPDMBLKCACHE pBlkCache,
1814 uint64_t off, size_t cb,
1815 size_t *pcbData)
1816{
1817 uint32_t cbEntry = 0;
1818
1819 *pcbData = pdmBlkCacheEntryBoundariesCalc(pBlkCache, off, (uint32_t)cb, &cbEntry);
1820 AssertReturn(cb <= UINT32_MAX, NULL);
1821
1822 PPDMBLKCACHEGLOBAL pCache = pBlkCache->pCache;
1823 pdmBlkCacheLockEnter(pCache);
1824
1825 PPDMBLKCACHEENTRY pEntryNew = NULL;
1826 uint8_t *pbBuffer = NULL;
1827 bool fEnough = pdmBlkCacheReclaim(pCache, cbEntry, true, &pbBuffer);
1828 if (fEnough)
1829 {
1830 LogFlow(("Evicted enough bytes (%u requested). Creating new cache entry\n", cbEntry));
1831
1832 pEntryNew = pdmBlkCacheEntryAlloc(pBlkCache, off, cbEntry, pbBuffer);
1833 if (RT_LIKELY(pEntryNew))
1834 {
1835 pdmBlkCacheEntryAddToList(&pCache->LruRecentlyUsedIn, pEntryNew);
1836 pdmBlkCacheAdd(pCache, cbEntry);
1837 pdmBlkCacheLockLeave(pCache);
1838
1839 pdmBlkCacheInsertEntry(pBlkCache, pEntryNew);
1840
1841 AssertMsg( (off >= pEntryNew->Core.Key)
1842 && (off + *pcbData <= pEntryNew->Core.KeyLast + 1),
1843 ("Overflow in calculation off=%llu\n", off));
1844 }
1845 else
1846 pdmBlkCacheLockLeave(pCache);
1847 }
1848 else
1849 pdmBlkCacheLockLeave(pCache);
1850
1851 return pEntryNew;
1852}
1853
1854static PPDMBLKCACHEREQ pdmBlkCacheReqAlloc(void *pvUser)
1855{
1856 PPDMBLKCACHEREQ pReq = (PPDMBLKCACHEREQ)RTMemAlloc(sizeof(PDMBLKCACHEREQ));
1857
1858 if (RT_LIKELY(pReq))
1859 {
1860 pReq->pvUser = pvUser;
1861 pReq->rcReq = VINF_SUCCESS;
1862 pReq->cXfersPending = 0;
1863 }
1864
1865 return pReq;
1866}
1867
1868static void pdmBlkCacheReqComplete(PPDMBLKCACHE pBlkCache, PPDMBLKCACHEREQ pReq)
1869{
1870 switch (pBlkCache->enmType)
1871 {
1872 case PDMBLKCACHETYPE_DEV:
1873 {
1874 pBlkCache->u.Dev.pfnXferComplete(pBlkCache->u.Dev.pDevIns,
1875 pReq->pvUser, pReq->rcReq);
1876 break;
1877 }
1878 case PDMBLKCACHETYPE_DRV:
1879 {
1880 pBlkCache->u.Drv.pfnXferComplete(pBlkCache->u.Drv.pDrvIns,
1881 pReq->pvUser, pReq->rcReq);
1882 break;
1883 }
1884 case PDMBLKCACHETYPE_USB:
1885 {
1886 pBlkCache->u.Usb.pfnXferComplete(pBlkCache->u.Usb.pUsbIns,
1887 pReq->pvUser, pReq->rcReq);
1888 break;
1889 }
1890 case PDMBLKCACHETYPE_INTERNAL:
1891 {
1892 pBlkCache->u.Int.pfnXferComplete(pBlkCache->u.Int.pvUser,
1893 pReq->pvUser, pReq->rcReq);
1894 break;
1895 }
1896 default:
1897 AssertMsgFailed(("Unknown block cache type!\n"));
1898 }
1899
1900 RTMemFree(pReq);
1901}
1902
1903static bool pdmBlkCacheReqUpdate(PPDMBLKCACHE pBlkCache, PPDMBLKCACHEREQ pReq,
1904 int rcReq, bool fCallHandler)
1905{
1906 if (RT_FAILURE(rcReq))
1907 ASMAtomicCmpXchgS32(&pReq->rcReq, rcReq, VINF_SUCCESS);
1908
1909 AssertMsg(pReq->cXfersPending > 0, ("No transfers are pending for this request\n"));
1910 uint32_t cXfersPending = ASMAtomicDecU32(&pReq->cXfersPending);
1911
1912 if (!cXfersPending)
1913 {
1914 if (fCallHandler)
1915 pdmBlkCacheReqComplete(pBlkCache, pReq);
1916 return true;
1917 }
1918
1919 LogFlowFunc(("pReq=%#p cXfersPending=%u\n", pReq, cXfersPending));
1920 return false;
1921}
1922
1923VMMR3DECL(int) PDMR3BlkCacheRead(PPDMBLKCACHE pBlkCache, uint64_t off,
1924 PCRTSGBUF pcSgBuf, size_t cbRead, void *pvUser)
1925{
1926 int rc = VINF_SUCCESS;
1927 PPDMBLKCACHEGLOBAL pCache = pBlkCache->pCache;
1928 PPDMBLKCACHEENTRY pEntry;
1929 PPDMBLKCACHEREQ pReq;
1930
1931 LogFlowFunc((": pBlkCache=%#p{%s} off=%llu pcSgBuf=%#p cbRead=%u pvUser=%#p\n",
1932 pBlkCache, pBlkCache->pszId, off, pcSgBuf, cbRead, pvUser));
1933
1934 AssertPtrReturn(pBlkCache, VERR_INVALID_POINTER);
1935 AssertReturn(!pBlkCache->fSuspended, VERR_INVALID_STATE);
1936
1937 RTSGBUF SgBuf;
1938 RTSgBufClone(&SgBuf, pcSgBuf);
1939
1940 /* Allocate new request structure. */
1941 pReq = pdmBlkCacheReqAlloc(pvUser);
1942 if (RT_UNLIKELY(!pReq))
1943 return VERR_NO_MEMORY;
1944
1945 /* Increment data transfer counter to keep the request valid while we access it. */
1946 ASMAtomicIncU32(&pReq->cXfersPending);
1947
1948 while (cbRead)
1949 {
1950 size_t cbToRead;
1951
1952 pEntry = pdmBlkCacheGetCacheEntryByOffset(pBlkCache, off);
1953
1954 /*
1955 * If there is no entry we try to create a new one eviciting unused pages
1956 * if the cache is full. If this is not possible we will pass the request through
1957 * and skip the caching (all entries may be still in progress so they can't
1958 * be evicted)
1959 * If we have an entry it can be in one of the LRU lists where the entry
1960 * contains data (recently used or frequently used LRU) so we can just read
1961 * the data we need and put the entry at the head of the frequently used LRU list.
1962 * In case the entry is in one of the ghost lists it doesn't contain any data.
1963 * We have to fetch it again evicting pages from either T1 or T2 to make room.
1964 */
1965 if (pEntry)
1966 {
1967 uint64_t offDiff = off - pEntry->Core.Key;
1968
1969 AssertMsg(off >= pEntry->Core.Key,
1970 ("Overflow in calculation off=%llu OffsetAligned=%llu\n",
1971 off, pEntry->Core.Key));
1972
1973 AssertPtr(pEntry->pList);
1974
1975 cbToRead = RT_MIN(pEntry->cbData - offDiff, cbRead);
1976
1977 AssertMsg(off + cbToRead <= pEntry->Core.Key + pEntry->Core.KeyLast + 1,
1978 ("Buffer of cache entry exceeded off=%llu cbToRead=%d\n",
1979 off, cbToRead));
1980
1981 cbRead -= cbToRead;
1982
1983 if (!cbRead)
1984 STAM_COUNTER_INC(&pCache->cHits);
1985 else
1986 STAM_COUNTER_INC(&pCache->cPartialHits);
1987
1988 STAM_COUNTER_ADD(&pCache->StatRead, cbToRead);
1989
1990 /* Ghost lists contain no data. */
1991 if ( (pEntry->pList == &pCache->LruRecentlyUsedIn)
1992 || (pEntry->pList == &pCache->LruFrequentlyUsed))
1993 {
1994 if (pdmBlkCacheEntryFlagIsSetClearAcquireLock(pBlkCache, pEntry,
1995 PDMBLKCACHE_ENTRY_IO_IN_PROGRESS,
1996 PDMBLKCACHE_ENTRY_IS_DIRTY))
1997 {
1998 /* Entry didn't completed yet. Append to the list */
1999 pdmBlkCacheEntryWaitersAdd(pEntry, pReq,
2000 &SgBuf, offDiff, cbToRead,
2001 false /* fWrite */);
2002 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
2003 }
2004 else
2005 {
2006 /* Read as much as we can from the entry. */
2007 RTSgBufCopyFromBuf(&SgBuf, pEntry->pbData + offDiff, cbToRead);
2008 }
2009
2010 /* Move this entry to the top position */
2011 if (pEntry->pList == &pCache->LruFrequentlyUsed)
2012 {
2013 pdmBlkCacheLockEnter(pCache);
2014 pdmBlkCacheEntryAddToList(&pCache->LruFrequentlyUsed, pEntry);
2015 pdmBlkCacheLockLeave(pCache);
2016 }
2017 /* Release the entry */
2018 pdmBlkCacheEntryRelease(pEntry);
2019 }
2020 else
2021 {
2022 uint8_t *pbBuffer = NULL;
2023
2024 LogFlow(("Fetching data for ghost entry %#p from file\n", pEntry));
2025
2026 pdmBlkCacheLockEnter(pCache);
2027 pdmBlkCacheEntryRemoveFromList(pEntry); /* Remove it before we remove data, otherwise it may get freed when evicting data. */
2028 bool fEnough = pdmBlkCacheReclaim(pCache, pEntry->cbData, true, &pbBuffer);
2029
2030 /* Move the entry to Am and fetch it to the cache. */
2031 if (fEnough)
2032 {
2033 pdmBlkCacheEntryAddToList(&pCache->LruFrequentlyUsed, pEntry);
2034 pdmBlkCacheAdd(pCache, pEntry->cbData);
2035 pdmBlkCacheLockLeave(pCache);
2036
2037 if (pbBuffer)
2038 pEntry->pbData = pbBuffer;
2039 else
2040 pEntry->pbData = (uint8_t *)RTMemPageAlloc(pEntry->cbData);
2041 AssertPtr(pEntry->pbData);
2042
2043 pdmBlkCacheEntryWaitersAdd(pEntry, pReq,
2044 &SgBuf, offDiff, cbToRead,
2045 false /* fWrite */);
2046 pdmBlkCacheEntryReadFromMedium(pEntry);
2047 /* Release the entry */
2048 pdmBlkCacheEntryRelease(pEntry);
2049 }
2050 else
2051 {
2052 RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
2053 STAM_PROFILE_ADV_START(&pCache->StatTreeRemove, Cache);
2054 RTAvlrU64Remove(pBlkCache->pTree, pEntry->Core.Key);
2055 STAM_PROFILE_ADV_STOP(&pCache->StatTreeRemove, Cache);
2056 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
2057
2058 pdmBlkCacheLockLeave(pCache);
2059
2060 RTMemFree(pEntry);
2061
2062 pdmBlkCacheRequestPassthrough(pBlkCache, pReq,
2063 &SgBuf, off, cbToRead,
2064 PDMBLKCACHEXFERDIR_READ);
2065 }
2066 }
2067 }
2068 else
2069 {
2070#ifdef VBOX_WITH_IO_READ_CACHE
2071 /* No entry found for this offset. Create a new entry and fetch the data to the cache. */
2072 PPDMBLKCACHEENTRY pEntryNew = pdmBlkCacheEntryCreate(pBlkCache,
2073 off, cbRead,
2074 &cbToRead);
2075
2076 cbRead -= cbToRead;
2077
2078 if (pEntryNew)
2079 {
2080 if (!cbRead)
2081 STAM_COUNTER_INC(&pCache->cMisses);
2082 else
2083 STAM_COUNTER_INC(&pCache->cPartialHits);
2084
2085 pdmBlkCacheEntryWaitersAdd(pEntryNew, pReq,
2086 &SgBuf,
2087 off - pEntryNew->Core.Key,
2088 cbToRead,
2089 false /* fWrite */);
2090 pdmBlkCacheEntryReadFromMedium(pEntryNew);
2091 pdmBlkCacheEntryRelease(pEntryNew); /* it is protected by the I/O in progress flag now. */
2092 }
2093 else
2094 {
2095 /*
2096 * There is not enough free space in the cache.
2097 * Pass the request directly to the I/O manager.
2098 */
2099 LogFlow(("Couldn't evict %u bytes from the cache. Remaining request will be passed through\n", cbToRead));
2100
2101 pdmBlkCacheRequestPassthrough(pBlkCache, pReq,
2102 &SgBuf, off, cbToRead,
2103 PDMBLKCACHEXFERDIR_READ);
2104 }
2105#else
2106 /* Clip read size if necessary. */
2107 PPDMBLKCACHEENTRY pEntryAbove;
2108 pdmBlkCacheGetCacheBestFitEntryByOffset(pBlkCache, off, &pEntryAbove);
2109
2110 if (pEntryAbove)
2111 {
2112 if (off + cbRead > pEntryAbove->Core.Key)
2113 cbToRead = pEntryAbove->Core.Key - off;
2114 else
2115 cbToRead = cbRead;
2116
2117 pdmBlkCacheEntryRelease(pEntryAbove);
2118 }
2119 else
2120 cbToRead = cbRead;
2121
2122 cbRead -= cbToRead;
2123 pdmBlkCacheRequestPassthrough(pBlkCache, pReq,
2124 &SgBuf, off, cbToRead,
2125 PDMBLKCACHEXFERDIR_READ);
2126#endif
2127 }
2128 off += cbToRead;
2129 }
2130
2131 if (!pdmBlkCacheReqUpdate(pBlkCache, pReq, rc, false))
2132 rc = VINF_AIO_TASK_PENDING;
2133 else
2134 {
2135 rc = pReq->rcReq;
2136 RTMemFree(pReq);
2137 }
2138
2139 LogFlowFunc((": Leave rc=%Rrc\n", rc));
2140
2141 return rc;
2142}
2143
2144VMMR3DECL(int) PDMR3BlkCacheWrite(PPDMBLKCACHE pBlkCache, uint64_t off,
2145 PCRTSGBUF pcSgBuf, size_t cbWrite, void *pvUser)
2146{
2147 int rc = VINF_SUCCESS;
2148 PPDMBLKCACHEGLOBAL pCache = pBlkCache->pCache;
2149 PPDMBLKCACHEENTRY pEntry;
2150 PPDMBLKCACHEREQ pReq;
2151
2152 LogFlowFunc((": pBlkCache=%#p{%s} off=%llu pcSgBuf=%#p cbWrite=%u pvUser=%#p\n",
2153 pBlkCache, pBlkCache->pszId, off, pcSgBuf, cbWrite, pvUser));
2154
2155 AssertPtrReturn(pBlkCache, VERR_INVALID_POINTER);
2156 AssertReturn(!pBlkCache->fSuspended, VERR_INVALID_STATE);
2157
2158 RTSGBUF SgBuf;
2159 RTSgBufClone(&SgBuf, pcSgBuf);
2160
2161 /* Allocate new request structure. */
2162 pReq = pdmBlkCacheReqAlloc(pvUser);
2163 if (RT_UNLIKELY(!pReq))
2164 return VERR_NO_MEMORY;
2165
2166 /* Increment data transfer counter to keep the request valid while we access it. */
2167 ASMAtomicIncU32(&pReq->cXfersPending);
2168
2169 while (cbWrite)
2170 {
2171 size_t cbToWrite;
2172
2173 pEntry = pdmBlkCacheGetCacheEntryByOffset(pBlkCache, off);
2174 if (pEntry)
2175 {
2176 /* Write the data into the entry and mark it as dirty */
2177 AssertPtr(pEntry->pList);
2178
2179 uint64_t offDiff = off - pEntry->Core.Key;
2180
2181 AssertMsg(off >= pEntry->Core.Key,
2182 ("Overflow in calculation off=%llu OffsetAligned=%llu\n",
2183 off, pEntry->Core.Key));
2184
2185 cbToWrite = RT_MIN(pEntry->cbData - offDiff, cbWrite);
2186 cbWrite -= cbToWrite;
2187
2188 if (!cbWrite)
2189 STAM_COUNTER_INC(&pCache->cHits);
2190 else
2191 STAM_COUNTER_INC(&pCache->cPartialHits);
2192
2193 STAM_COUNTER_ADD(&pCache->StatWritten, cbToWrite);
2194
2195 /* Ghost lists contain no data. */
2196 if ( (pEntry->pList == &pCache->LruRecentlyUsedIn)
2197 || (pEntry->pList == &pCache->LruFrequentlyUsed))
2198 {
2199 /* Check if the entry is dirty. */
2200 if (pdmBlkCacheEntryFlagIsSetClearAcquireLock(pBlkCache, pEntry,
2201 PDMBLKCACHE_ENTRY_IS_DIRTY,
2202 0))
2203 {
2204 /* If it is already dirty but not in progress just update the data. */
2205 if (!(pEntry->fFlags & PDMBLKCACHE_ENTRY_IO_IN_PROGRESS))
2206 RTSgBufCopyToBuf(&SgBuf, pEntry->pbData + offDiff, cbToWrite);
2207 else
2208 {
2209 /* The data isn't written to the file yet */
2210 pdmBlkCacheEntryWaitersAdd(pEntry, pReq,
2211 &SgBuf, offDiff, cbToWrite,
2212 true /* fWrite */);
2213 STAM_COUNTER_INC(&pBlkCache->StatWriteDeferred);
2214 }
2215
2216 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
2217 }
2218 else /* Dirty bit not set */
2219 {
2220 /*
2221 * Check if a read is in progress for this entry.
2222 * We have to defer processing in that case.
2223 */
2224 if (pdmBlkCacheEntryFlagIsSetClearAcquireLock(pBlkCache, pEntry,
2225 PDMBLKCACHE_ENTRY_IO_IN_PROGRESS,
2226 0))
2227 {
2228 pdmBlkCacheEntryWaitersAdd(pEntry, pReq,
2229 &SgBuf, offDiff, cbToWrite,
2230 true /* fWrite */);
2231 STAM_COUNTER_INC(&pBlkCache->StatWriteDeferred);
2232 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
2233 }
2234 else /* I/O in progress flag not set */
2235 {
2236 /* Write as much as we can into the entry and update the file. */
2237 RTSgBufCopyToBuf(&SgBuf, pEntry->pbData + offDiff, cbToWrite);
2238
2239 bool fCommit = pdmBlkCacheAddDirtyEntry(pBlkCache, pEntry);
2240 if (fCommit)
2241 pdmBlkCacheCommitDirtyEntries(pCache);
2242 }
2243 } /* Dirty bit not set */
2244
2245 /* Move this entry to the top position */
2246 if (pEntry->pList == &pCache->LruFrequentlyUsed)
2247 {
2248 pdmBlkCacheLockEnter(pCache);
2249 pdmBlkCacheEntryAddToList(&pCache->LruFrequentlyUsed, pEntry);
2250 pdmBlkCacheLockLeave(pCache);
2251 }
2252
2253 pdmBlkCacheEntryRelease(pEntry);
2254 }
2255 else /* Entry is on the ghost list */
2256 {
2257 uint8_t *pbBuffer = NULL;
2258
2259 pdmBlkCacheLockEnter(pCache);
2260 pdmBlkCacheEntryRemoveFromList(pEntry); /* Remove it before we remove data, otherwise it may get freed when evicting data. */
2261 bool fEnough = pdmBlkCacheReclaim(pCache, pEntry->cbData, true, &pbBuffer);
2262
2263 if (fEnough)
2264 {
2265 /* Move the entry to Am and fetch it to the cache. */
2266 pdmBlkCacheEntryAddToList(&pCache->LruFrequentlyUsed, pEntry);
2267 pdmBlkCacheAdd(pCache, pEntry->cbData);
2268 pdmBlkCacheLockLeave(pCache);
2269
2270 if (pbBuffer)
2271 pEntry->pbData = pbBuffer;
2272 else
2273 pEntry->pbData = (uint8_t *)RTMemPageAlloc(pEntry->cbData);
2274 AssertPtr(pEntry->pbData);
2275
2276 pdmBlkCacheEntryWaitersAdd(pEntry, pReq,
2277 &SgBuf, offDiff, cbToWrite,
2278 true /* fWrite */);
2279 STAM_COUNTER_INC(&pBlkCache->StatWriteDeferred);
2280 pdmBlkCacheEntryReadFromMedium(pEntry);
2281
2282 /* Release the reference. If it is still needed the I/O in progress flag should protect it now. */
2283 pdmBlkCacheEntryRelease(pEntry);
2284 }
2285 else
2286 {
2287 RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
2288 STAM_PROFILE_ADV_START(&pCache->StatTreeRemove, Cache);
2289 RTAvlrU64Remove(pBlkCache->pTree, pEntry->Core.Key);
2290 STAM_PROFILE_ADV_STOP(&pCache->StatTreeRemove, Cache);
2291 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
2292
2293 pdmBlkCacheLockLeave(pCache);
2294
2295 RTMemFree(pEntry);
2296 pdmBlkCacheRequestPassthrough(pBlkCache, pReq,
2297 &SgBuf, off, cbToWrite,
2298 PDMBLKCACHEXFERDIR_WRITE);
2299 }
2300 }
2301 }
2302 else /* No entry found */
2303 {
2304 /*
2305 * No entry found. Try to create a new cache entry to store the data in and if that fails
2306 * write directly to the file.
2307 */
2308 PPDMBLKCACHEENTRY pEntryNew = pdmBlkCacheEntryCreate(pBlkCache,
2309 off, cbWrite,
2310 &cbToWrite);
2311
2312 cbWrite -= cbToWrite;
2313
2314 if (pEntryNew)
2315 {
2316 uint64_t offDiff = off - pEntryNew->Core.Key;
2317
2318 STAM_COUNTER_INC(&pCache->cHits);
2319
2320 /*
2321 * Check if it is possible to just write the data without waiting
2322 * for it to get fetched first.
2323 */
2324 if (!offDiff && pEntryNew->cbData == cbToWrite)
2325 {
2326 RTSgBufCopyToBuf(&SgBuf, pEntryNew->pbData, cbToWrite);
2327
2328 bool fCommit = pdmBlkCacheAddDirtyEntry(pBlkCache, pEntryNew);
2329 if (fCommit)
2330 pdmBlkCacheCommitDirtyEntries(pCache);
2331 STAM_COUNTER_ADD(&pCache->StatWritten, cbToWrite);
2332 }
2333 else
2334 {
2335 /* Defer the write and fetch the data from the endpoint. */
2336 pdmBlkCacheEntryWaitersAdd(pEntryNew, pReq,
2337 &SgBuf, offDiff, cbToWrite,
2338 true /* fWrite */);
2339 STAM_COUNTER_INC(&pBlkCache->StatWriteDeferred);
2340 pdmBlkCacheEntryReadFromMedium(pEntryNew);
2341 }
2342
2343 pdmBlkCacheEntryRelease(pEntryNew);
2344 }
2345 else
2346 {
2347 /*
2348 * There is not enough free space in the cache.
2349 * Pass the request directly to the I/O manager.
2350 */
2351 LogFlow(("Couldn't evict %u bytes from the cache. Remaining request will be passed through\n", cbToWrite));
2352
2353 STAM_COUNTER_INC(&pCache->cMisses);
2354
2355 pdmBlkCacheRequestPassthrough(pBlkCache, pReq,
2356 &SgBuf, off, cbToWrite,
2357 PDMBLKCACHEXFERDIR_WRITE);
2358 }
2359 }
2360
2361 off += cbToWrite;
2362 }
2363
2364 if (!pdmBlkCacheReqUpdate(pBlkCache, pReq, rc, false))
2365 rc = VINF_AIO_TASK_PENDING;
2366 else
2367 {
2368 rc = pReq->rcReq;
2369 RTMemFree(pReq);
2370 }
2371
2372 LogFlowFunc((": Leave rc=%Rrc\n", rc));
2373
2374 return rc;
2375}
2376
2377VMMR3DECL(int) PDMR3BlkCacheFlush(PPDMBLKCACHE pBlkCache, void *pvUser)
2378{
2379 int rc = VINF_SUCCESS;
2380 PPDMBLKCACHEREQ pReq;
2381
2382 LogFlowFunc((": pBlkCache=%#p{%s}\n", pBlkCache, pBlkCache->pszId));
2383
2384 AssertPtrReturn(pBlkCache, VERR_INVALID_POINTER);
2385 AssertReturn(!pBlkCache->fSuspended, VERR_INVALID_STATE);
2386
2387 /* Commit dirty entries in the cache. */
2388 pdmBlkCacheCommit(pBlkCache);
2389
2390 /* Allocate new request structure. */
2391 pReq = pdmBlkCacheReqAlloc(pvUser);
2392 if (RT_UNLIKELY(!pReq))
2393 return VERR_NO_MEMORY;
2394
2395 rc = pdmBlkCacheRequestPassthrough(pBlkCache, pReq, NULL, 0, 0,
2396 PDMBLKCACHEXFERDIR_FLUSH);
2397 AssertRC(rc);
2398
2399 LogFlowFunc((": Leave rc=%Rrc\n", rc));
2400 return VINF_AIO_TASK_PENDING;
2401}
2402
2403VMMR3DECL(int) PDMR3BlkCacheDiscard(PPDMBLKCACHE pBlkCache, PCRTRANGE paRanges,
2404 unsigned cRanges, void *pvUser)
2405{
2406 int rc = VINF_SUCCESS;
2407 PPDMBLKCACHEGLOBAL pCache = pBlkCache->pCache;
2408 PPDMBLKCACHEENTRY pEntry;
2409 PPDMBLKCACHEREQ pReq;
2410
2411 LogFlowFunc((": pBlkCache=%#p{%s} paRanges=%#p cRanges=%u pvUser=%#p\n",
2412 pBlkCache, pBlkCache->pszId, paRanges, cRanges, pvUser));
2413
2414 AssertPtrReturn(pBlkCache, VERR_INVALID_POINTER);
2415 AssertReturn(!pBlkCache->fSuspended, VERR_INVALID_STATE);
2416
2417 /* Allocate new request structure. */
2418 pReq = pdmBlkCacheReqAlloc(pvUser);
2419 if (RT_UNLIKELY(!pReq))
2420 return VERR_NO_MEMORY;
2421
2422 /* Increment data transfer counter to keep the request valid while we access it. */
2423 ASMAtomicIncU32(&pReq->cXfersPending);
2424
2425 for (unsigned i = 0; i < cRanges; i++)
2426 {
2427 uint64_t offCur = paRanges[i].offStart;
2428 size_t cbLeft = paRanges[i].cbRange;
2429
2430 while (cbLeft)
2431 {
2432 size_t cbThisDiscard = 0;
2433
2434 pEntry = pdmBlkCacheGetCacheEntryByOffset(pBlkCache, offCur);
2435
2436 if (pEntry)
2437 {
2438 /* Write the data into the entry and mark it as dirty */
2439 AssertPtr(pEntry->pList);
2440
2441 uint64_t offDiff = offCur - pEntry->Core.Key;
2442
2443 AssertMsg(offCur >= pEntry->Core.Key,
2444 ("Overflow in calculation offCur=%llu OffsetAligned=%llu\n",
2445 offCur, pEntry->Core.Key));
2446
2447 cbThisDiscard = RT_MIN(pEntry->cbData - offDiff, cbLeft);
2448
2449 /* Ghost lists contain no data. */
2450 if ( (pEntry->pList == &pCache->LruRecentlyUsedIn)
2451 || (pEntry->pList == &pCache->LruFrequentlyUsed))
2452 {
2453 /* Check if the entry is dirty. */
2454 if (pdmBlkCacheEntryFlagIsSetClearAcquireLock(pBlkCache, pEntry,
2455 PDMBLKCACHE_ENTRY_IS_DIRTY,
2456 0))
2457 {
2458 /* If it is dirty but not yet in progress remove it. */
2459 if (!(pEntry->fFlags & PDMBLKCACHE_ENTRY_IO_IN_PROGRESS))
2460 {
2461 pdmBlkCacheLockEnter(pCache);
2462 pdmBlkCacheEntryRemoveFromList(pEntry);
2463
2464 STAM_PROFILE_ADV_START(&pCache->StatTreeRemove, Cache);
2465 RTAvlrU64Remove(pBlkCache->pTree, pEntry->Core.Key);
2466 STAM_PROFILE_ADV_STOP(&pCache->StatTreeRemove, Cache);
2467
2468 pdmBlkCacheLockLeave(pCache);
2469
2470 RTMemFree(pEntry);
2471 }
2472 else
2473 {
2474#if 0
2475 /* The data isn't written to the file yet */
2476 pdmBlkCacheEntryWaitersAdd(pEntry, pReq,
2477 &SgBuf, offDiff, cbToWrite,
2478 true /* fWrite */);
2479 STAM_COUNTER_INC(&pBlkCache->StatWriteDeferred);
2480#endif
2481 }
2482
2483 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
2484 pdmBlkCacheEntryRelease(pEntry);
2485 }
2486 else /* Dirty bit not set */
2487 {
2488 /*
2489 * Check if a read is in progress for this entry.
2490 * We have to defer processing in that case.
2491 */
2492 if(pdmBlkCacheEntryFlagIsSetClearAcquireLock(pBlkCache, pEntry,
2493 PDMBLKCACHE_ENTRY_IO_IN_PROGRESS,
2494 0))
2495 {
2496#if 0
2497 pdmBlkCacheEntryWaitersAdd(pEntry, pReq,
2498 &SgBuf, offDiff, cbToWrite,
2499 true /* fWrite */);
2500#endif
2501 STAM_COUNTER_INC(&pBlkCache->StatWriteDeferred);
2502 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
2503 pdmBlkCacheEntryRelease(pEntry);
2504 }
2505 else /* I/O in progress flag not set */
2506 {
2507 pdmBlkCacheLockEnter(pCache);
2508 pdmBlkCacheEntryRemoveFromList(pEntry);
2509
2510 RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
2511 STAM_PROFILE_ADV_START(&pCache->StatTreeRemove, Cache);
2512 RTAvlrU64Remove(pBlkCache->pTree, pEntry->Core.Key);
2513 STAM_PROFILE_ADV_STOP(&pCache->StatTreeRemove, Cache);
2514 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
2515
2516 pdmBlkCacheLockLeave(pCache);
2517
2518 RTMemFree(pEntry);
2519 }
2520 } /* Dirty bit not set */
2521 }
2522 else /* Entry is on the ghost list just remove cache entry. */
2523 {
2524 pdmBlkCacheLockEnter(pCache);
2525 pdmBlkCacheEntryRemoveFromList(pEntry);
2526
2527 RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
2528 STAM_PROFILE_ADV_START(&pCache->StatTreeRemove, Cache);
2529 RTAvlrU64Remove(pBlkCache->pTree, pEntry->Core.Key);
2530 STAM_PROFILE_ADV_STOP(&pCache->StatTreeRemove, Cache);
2531 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
2532
2533 pdmBlkCacheLockLeave(pCache);
2534
2535 RTMemFree(pEntry);
2536 }
2537 }
2538 /* else: no entry found. */
2539
2540 offCur += cbThisDiscard;
2541 cbLeft -= cbThisDiscard;
2542 }
2543 }
2544
2545 if (!pdmBlkCacheReqUpdate(pBlkCache, pReq, rc, false))
2546 rc = VINF_AIO_TASK_PENDING;
2547 else
2548 {
2549 rc = pReq->rcReq;
2550 RTMemFree(pReq);
2551 }
2552
2553 LogFlowFunc((": Leave rc=%Rrc\n", rc));
2554
2555 return rc;
2556}
2557
2558/**
2559 * Completes a task segment freeing all resources and completes the task handle
2560 * if everything was transferred.
2561 *
2562 * @returns Next task segment handle.
2563 * @param pTaskSeg Task segment to complete.
2564 * @param rc Status code to set.
2565 */
2566static PPDMBLKCACHEWAITER pdmBlkCacheWaiterComplete(PPDMBLKCACHE pBlkCache,
2567 PPDMBLKCACHEWAITER pWaiter,
2568 int rc)
2569{
2570 PPDMBLKCACHEWAITER pNext = pWaiter->pNext;
2571 PPDMBLKCACHEREQ pReq = pWaiter->pReq;
2572
2573 pdmBlkCacheReqUpdate(pBlkCache, pReq, rc, true);
2574
2575 RTMemFree(pWaiter);
2576
2577 return pNext;
2578}
2579
2580static void pdmBlkCacheIoXferCompleteEntry(PPDMBLKCACHE pBlkCache, PPDMBLKCACHEIOXFER hIoXfer, int rcIoXfer)
2581{
2582 PPDMBLKCACHEENTRY pEntry = hIoXfer->pEntry;
2583 PPDMBLKCACHEGLOBAL pCache = pBlkCache->pCache;
2584
2585 /* Reference the entry now as we are clearing the I/O in progress flag
2586 * which protected the entry till now. */
2587 pdmBlkCacheEntryRef(pEntry);
2588
2589 RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
2590 pEntry->fFlags &= ~PDMBLKCACHE_ENTRY_IO_IN_PROGRESS;
2591
2592 /* Process waiting segment list. The data in entry might have changed in-between. */
2593 bool fDirty = false;
2594 PPDMBLKCACHEWAITER pComplete = pEntry->pWaitingHead;
2595 PPDMBLKCACHEWAITER pCurr = pComplete;
2596
2597 AssertMsg((pCurr && pEntry->pWaitingTail) || (!pCurr && !pEntry->pWaitingTail),
2598 ("The list tail was not updated correctly\n"));
2599 pEntry->pWaitingTail = NULL;
2600 pEntry->pWaitingHead = NULL;
2601
2602 if (hIoXfer->enmXferDir == PDMBLKCACHEXFERDIR_WRITE)
2603 {
2604 /*
2605 * An error here is difficult to handle as the original request completed already.
2606 * The error is logged for now and the VM is paused.
2607 * If the user continues the entry is written again in the hope
2608 * the user fixed the problem and the next write succeeds.
2609 */
2610 if (RT_FAILURE(rcIoXfer))
2611 {
2612 LogRel(("I/O cache: Error while writing entry at offset %llu (%u bytes) to medium \"%s\" (rc=%Rrc)\n",
2613 pEntry->Core.Key, pEntry->cbData, pBlkCache->pszId, rcIoXfer));
2614
2615 if (!ASMAtomicXchgBool(&pCache->fIoErrorVmSuspended, true))
2616 {
2617 int rc = VMSetRuntimeError(pCache->pVM, VMSETRTERR_FLAGS_SUSPEND | VMSETRTERR_FLAGS_NO_WAIT, "BLKCACHE_IOERR",
2618 N_("The I/O cache encountered an error while updating data in medium \"%s\" (rc=%Rrc). "
2619 "Make sure there is enough free space on the disk and that the disk is working properly. "
2620 "Operation can be resumed afterwards"),
2621 pBlkCache->pszId, rcIoXfer);
2622 AssertRC(rc);
2623 }
2624
2625 /* Mark the entry as dirty again to get it added to the list later on. */
2626 fDirty = true;
2627 }
2628
2629 pEntry->fFlags &= ~PDMBLKCACHE_ENTRY_IS_DIRTY;
2630
2631 while (pCurr)
2632 {
2633 AssertMsg(pCurr->fWrite, ("Completed write entries should never have read tasks attached\n"));
2634
2635 RTSgBufCopyToBuf(&pCurr->SgBuf, pEntry->pbData + pCurr->offCacheEntry, pCurr->cbTransfer);
2636 fDirty = true;
2637 pCurr = pCurr->pNext;
2638 }
2639 }
2640 else
2641 {
2642 AssertMsg(hIoXfer->enmXferDir == PDMBLKCACHEXFERDIR_READ, ("Invalid transfer type\n"));
2643 AssertMsg(!(pEntry->fFlags & PDMBLKCACHE_ENTRY_IS_DIRTY),
2644 ("Invalid flags set\n"));
2645
2646 while (pCurr)
2647 {
2648 if (pCurr->fWrite)
2649 {
2650 RTSgBufCopyToBuf(&pCurr->SgBuf, pEntry->pbData + pCurr->offCacheEntry, pCurr->cbTransfer);
2651 fDirty = true;
2652 }
2653 else
2654 RTSgBufCopyFromBuf(&pCurr->SgBuf, pEntry->pbData + pCurr->offCacheEntry, pCurr->cbTransfer);
2655
2656 pCurr = pCurr->pNext;
2657 }
2658 }
2659
2660 bool fCommit = false;
2661 if (fDirty)
2662 fCommit = pdmBlkCacheAddDirtyEntry(pBlkCache, pEntry);
2663
2664 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
2665
2666 /* Dereference so that it isn't protected anymore except we issued anyother write for it. */
2667 pdmBlkCacheEntryRelease(pEntry);
2668
2669 if (fCommit)
2670 pdmBlkCacheCommitDirtyEntries(pCache);
2671
2672 /* Complete waiters now. */
2673 while (pComplete)
2674 pComplete = pdmBlkCacheWaiterComplete(pBlkCache, pComplete, rcIoXfer);
2675}
2676
2677VMMR3DECL(void) PDMR3BlkCacheIoXferComplete(PPDMBLKCACHE pBlkCache, PPDMBLKCACHEIOXFER hIoXfer, int rcIoXfer)
2678{
2679 LogFlowFunc(("pBlkCache=%#p hIoXfer=%#p rcIoXfer=%Rrc\n", pBlkCache, hIoXfer, rcIoXfer));
2680
2681 if (hIoXfer->fIoCache)
2682 pdmBlkCacheIoXferCompleteEntry(pBlkCache, hIoXfer, rcIoXfer);
2683 else
2684 pdmBlkCacheReqUpdate(pBlkCache, hIoXfer->pReq, rcIoXfer, true);
2685 RTMemFree(hIoXfer);
2686}
2687
2688/**
2689 * Callback for the AVL do with all routine. Waits for a cachen entry to finish any pending I/O.
2690 *
2691 * @returns IPRT status code.
2692 * @param pNode The node to destroy.
2693 * @param pvUser Opaque user data.
2694 */
2695static int pdmBlkCacheEntryQuiesce(PAVLRU64NODECORE pNode, void *pvUser)
2696{
2697 PPDMBLKCACHEENTRY pEntry = (PPDMBLKCACHEENTRY)pNode;
2698 PPDMBLKCACHE pBlkCache = pEntry->pBlkCache;
2699 NOREF(pvUser);
2700
2701 while (ASMAtomicReadU32(&pEntry->fFlags) & PDMBLKCACHE_ENTRY_IO_IN_PROGRESS)
2702 {
2703 /* Leave the locks to let the I/O thread make progress but reference the entry to prevent eviction. */
2704 pdmBlkCacheEntryRef(pEntry);
2705 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
2706
2707 RTThreadSleep(1);
2708
2709 /* Re-enter all locks and drop the reference. */
2710 RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
2711 pdmBlkCacheEntryRelease(pEntry);
2712 }
2713
2714 AssertMsg(!(pEntry->fFlags & PDMBLKCACHE_ENTRY_IO_IN_PROGRESS),
2715 ("Entry is dirty and/or still in progress fFlags=%#x\n", pEntry->fFlags));
2716
2717 return VINF_SUCCESS;
2718}
2719
2720VMMR3DECL(int) PDMR3BlkCacheSuspend(PPDMBLKCACHE pBlkCache)
2721{
2722 int rc = VINF_SUCCESS;
2723 LogFlowFunc(("pBlkCache=%#p\n", pBlkCache));
2724
2725 AssertPtrReturn(pBlkCache, VERR_INVALID_POINTER);
2726
2727 if (!ASMAtomicReadBool(&pBlkCache->pCache->fIoErrorVmSuspended))
2728 pdmBlkCacheCommit(pBlkCache); /* Can issue new I/O requests. */
2729 ASMAtomicXchgBool(&pBlkCache->fSuspended, true);
2730
2731 /* Wait for all I/O to complete. */
2732 RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
2733 rc = RTAvlrU64DoWithAll(pBlkCache->pTree, true, pdmBlkCacheEntryQuiesce, NULL);
2734 AssertRC(rc);
2735 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
2736
2737 return rc;
2738}
2739
2740VMMR3DECL(int) PDMR3BlkCacheResume(PPDMBLKCACHE pBlkCache)
2741{
2742 LogFlowFunc(("pBlkCache=%#p\n", pBlkCache));
2743
2744 AssertPtrReturn(pBlkCache, VERR_INVALID_POINTER);
2745
2746 ASMAtomicXchgBool(&pBlkCache->fSuspended, false);
2747
2748 return VINF_SUCCESS;
2749}
2750
2751VMMR3DECL(int) PDMR3BlkCacheClear(PPDMBLKCACHE pBlkCache)
2752{
2753 int rc = VINF_SUCCESS;
2754 PPDMBLKCACHEGLOBAL pCache = pBlkCache->pCache;
2755
2756 /*
2757 * Commit all dirty entries now (they are waited on for completion during the
2758 * destruction of the AVL tree below).
2759 * The exception is if the VM was paused because of an I/O error before.
2760 */
2761 if (!ASMAtomicReadBool(&pCache->fIoErrorVmSuspended))
2762 pdmBlkCacheCommit(pBlkCache);
2763
2764 /* Make sure nobody is accessing the cache while we delete the tree. */
2765 pdmBlkCacheLockEnter(pCache);
2766 RTSemRWRequestWrite(pBlkCache->SemRWEntries, RT_INDEFINITE_WAIT);
2767 RTAvlrU64Destroy(pBlkCache->pTree, pdmBlkCacheEntryDestroy, pCache);
2768 RTSemRWReleaseWrite(pBlkCache->SemRWEntries);
2769
2770 pdmBlkCacheLockLeave(pCache);
2771 return rc;
2772}
2773
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