Windows Driver: Add registry settings to control driver internal encryption queue Under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\veracrypt: - VeraCryptEncryptionFragmentSize (REG_DWORD): size of encryption data fragment in KiB. Default is 256. - VeraCryptEncryptionIoRequestCount (REG_DWORD): maximum number of parallel I/O requests. Default is 16. - VeraCryptEncryptionItemCount (REG_DWORD): maximum number of encryption queue items processed in parallel. Default is 8.

src/Common/Apidrvr.h

@@ -407,6 +407,10 @@ typedef struct
 #define TC_DRIVER_CONFIG_REG_VALUE_NAME DRIVER_STR("VeraCryptConfig")
 #define TC_ENCRYPTION_FREE_CPU_COUNT_REG_VALUE_NAME DRIVER_STR("VeraCryptEncryptionFreeCpuCount")
 
+#define VC_ENCRYPTION_IO_REQUEST_COUNT DRIVER_STR("VeraCryptEncryptionIoRequestCount")
+#define VC_ENCRYPTION_ITEM_COUNT DRIVER_STR("VeraCryptEncryptionItemCount")
+#define VC_ENCRYPTION_FRAGMENT_SIZE DRIVER_STR("VeraCryptEncryptionFragmentSize")
+
 // WARNING: Modifying the following values can introduce incompatibility with previous versions.
 #define TC_DRIVER_CONFIG_CACHE_BOOT_PASSWORD						0x1
 #define TC_DRIVER_CONFIG_CACHE_BOOT_PASSWORD_FOR_SYS_FAVORITES		0x2

src/Driver/EncryptedIoQueue.c

@@ -775,9 +775,10 @@ static VOID MainThreadProc (PVOID threadArg)
 
 			while (dataRemaining > 0)
 			{
-				BOOL isLastFragment = dataRemaining <= TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE;
+				ULONG queueFragmentSize = queue->FragmentSize;
+				BOOL isLastFragment = dataRemaining <= queueFragmentSize;
 
-				ULONG dataFragmentLength = isLastFragment ? dataRemaining : TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE;
+				ULONG dataFragmentLength = isLastFragment ? dataRemaining : queueFragmentSize;
 				activeFragmentBuffer = (activeFragmentBuffer == queue->FragmentBufferA ? queue->FragmentBufferB : queue->FragmentBufferA);
 
 				InterlockedIncrement (&queue->IoThreadPendingRequestCount);
@@ -847,9 +848,9 @@ static VOID MainThreadProc (PVOID threadArg)
 				if (isLastFragment)
 					break;
 
-				dataRemaining -= TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE;
+				dataRemaining -= queueFragmentSize;
-				dataBuffer += TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE;
+				dataBuffer += queueFragmentSize;
-				fragmentOffset.QuadPart += TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE;
+				fragmentOffset.QuadPart += queueFragmentSize;
 			}
 		}
 	}
@@ -971,7 +972,11 @@ NTSTATUS EncryptedIoQueueStart (EncryptedIoQueue *queue)
 {
 	NTSTATUS status;
 	EncryptedIoQueueBuffer *buffer;
-	int i;
+	int i, preallocatedIoRequestCount, preallocatedItemCount, fragmentSize;
+
+	preallocatedIoRequestCount = EncryptionIoRequestCount;
+	preallocatedItemCount = EncryptionItemCount;
+	fragmentSize = EncryptionFragmentSize;
 
 	queue->StartPending = TRUE;
 	queue->ThreadExitRequested = FALSE;
@@ -986,30 +991,84 @@ NTSTATUS EncryptedIoQueueStart (EncryptedIoQueue *queue)
 	KeInitializeEvent (&queue->PoolBufferFreeEvent, SynchronizationEvent, FALSE);
 	KeInitializeEvent (&queue->QueueResumedEvent, SynchronizationEvent, FALSE);
 
-	queue->FragmentBufferA = TCalloc (TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE);
+retry_fragmentAllocate:
+	queue->FragmentBufferA = TCalloc (fragmentSize);
 	if (!queue->FragmentBufferA)
-		goto noMemory;
+	{
+		if (fragmentSize > TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE)
+		{
+			fragmentSize = TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE;
+			goto retry_fragmentAllocate;
+		}
+		else
+			goto noMemory;
+	}
 
-	queue->FragmentBufferB = TCalloc (TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE);
+	queue->FragmentBufferB = TCalloc (fragmentSize);
 	if (!queue->FragmentBufferB)
-		goto noMemory;
+	{
+		if (fragmentSize > TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE)
+		{
+			fragmentSize = TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE;
+			TCfree (queue->FragmentBufferA);
+			queue->FragmentBufferA = NULL;
+			goto retry_fragmentAllocate;
+		}
+		else
+			goto noMemory;
+	}
+
+	queue->ReadAheadBufferValid = FALSE;
+	queue->ReadAheadBuffer = TCalloc (fragmentSize);
+	if (!queue->ReadAheadBuffer)
+	{
+		if (fragmentSize > TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE)
+		{
+			fragmentSize = TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE;
+			TCfree (queue->FragmentBufferA);
+			TCfree (queue->FragmentBufferB);
+			queue->FragmentBufferA = NULL;
+			queue->FragmentBufferB = NULL;
+			goto retry_fragmentAllocate;
+		}
+		else
+			goto noMemory;
+	}
+
+	queue->FragmentSize = fragmentSize;
 
 	KeInitializeEvent (&queue->FragmentBufferAFreeEvent, SynchronizationEvent, TRUE);
 	KeInitializeEvent (&queue->FragmentBufferBFreeEvent, SynchronizationEvent, TRUE);
 
-	queue->ReadAheadBufferValid = FALSE;
+retry_preallocated:
-	queue->ReadAheadBuffer = TCalloc (TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE);
-	if (!queue->ReadAheadBuffer)
-		goto noMemory;
-
 	// Preallocate buffers
-	for (i = 0; i < TC_ENC_IO_QUEUE_PREALLOCATED_IO_REQUEST_COUNT; ++i)
+	for (i = 0; i < preallocatedIoRequestCount; ++i)
 	{
-		if (i < TC_ENC_IO_QUEUE_PREALLOCATED_ITEM_COUNT && !GetPoolBuffer (queue, sizeof (EncryptedIoQueueItem)))
+		if (i < preallocatedItemCount && !GetPoolBuffer (queue, sizeof (EncryptedIoQueueItem)))
-			goto noMemory;
+		{
+			if (preallocatedItemCount > TC_ENC_IO_QUEUE_PREALLOCATED_ITEM_COUNT)
+			{
+				preallocatedItemCount = TC_ENC_IO_QUEUE_PREALLOCATED_ITEM_COUNT;
+				preallocatedIoRequestCount = TC_ENC_IO_QUEUE_PREALLOCATED_IO_REQUEST_COUNT;
+				FreePoolBuffers (queue);
+				goto retry_preallocated;
+			}
+			else
+				goto noMemory;
+		}
 
 		if (!GetPoolBuffer (queue, sizeof (EncryptedIoRequest)))
-			goto noMemory;
+		{
+			if (preallocatedIoRequestCount > TC_ENC_IO_QUEUE_PREALLOCATED_IO_REQUEST_COUNT)
+			{
+				preallocatedItemCount = TC_ENC_IO_QUEUE_PREALLOCATED_ITEM_COUNT;
+				preallocatedIoRequestCount = TC_ENC_IO_QUEUE_PREALLOCATED_IO_REQUEST_COUNT;
+				FreePoolBuffers (queue);
+				goto retry_preallocated;
+			}
+			else
+				goto noMemory;
+		}
 	}
 
 	for (buffer = queue->FirstPoolBuffer; buffer != NULL; buffer = buffer->NextBuffer)

src/Driver/EncryptedIoQueue.h

@@ -121,6 +121,8 @@ typedef struct
  	SIZE_T SecRegionSize;
 
 	volatile BOOL ThreadBlockReadWrite;
+
+	int FragmentSize;
 }  EncryptedIoQueue;
 
 

src/Driver/Ntdriver.c

@@ -148,6 +148,9 @@ static KeAreAllApcsDisabledFn KeAreAllApcsDisabledPtr = NULL;
 static KeSetSystemGroupAffinityThreadFn KeSetSystemGroupAffinityThreadPtr = NULL;
 static KeQueryActiveGroupCountFn KeQueryActiveGroupCountPtr = NULL;
 static KeQueryActiveProcessorCountExFn KeQueryActiveProcessorCountExPtr = NULL;
+int EncryptionIoRequestCount = 0;
+int EncryptionItemCount = 0;
+int EncryptionFragmentSize = 0;
 
 POOL_TYPE ExDefaultNonPagedPoolType = NonPagedPool;
 ULONG ExDefaultMdlProtection = 0;
@@ -4795,6 +4798,50 @@ NTSTATUS ReadRegistryConfigFlags (BOOL driverEntry)
 		TCfree (data);
 	}
 
+	if (driverEntry && NT_SUCCESS (TCReadRegistryKey (&name, VC_ENCRYPTION_IO_REQUEST_COUNT, &data)))
+	{
+		if (data->Type == REG_DWORD)
+			EncryptionIoRequestCount = *(uint32 *) data->Data;
+
+		TCfree (data);
+	}
+
+	if (driverEntry && NT_SUCCESS (TCReadRegistryKey (&name, VC_ENCRYPTION_ITEM_COUNT, &data)))
+	{
+		if (data->Type == REG_DWORD)
+			EncryptionItemCount = *(uint32 *) data->Data;
+
+		TCfree (data);
+	}
+
+	if (driverEntry && NT_SUCCESS (TCReadRegistryKey (&name, VC_ENCRYPTION_FRAGMENT_SIZE, &data)))
+	{
+		if (data->Type == REG_DWORD)
+			EncryptionFragmentSize = *(uint32 *) data->Data;
+
+		TCfree (data);
+	}
+
+	if (driverEntry)
+	{
+		if (EncryptionIoRequestCount < TC_ENC_IO_QUEUE_PREALLOCATED_IO_REQUEST_COUNT)
+			EncryptionIoRequestCount = TC_ENC_IO_QUEUE_PREALLOCATED_IO_REQUEST_COUNT;
+
+		if (EncryptionItemCount == 0)
+			EncryptionItemCount = EncryptionIoRequestCount / 2;
+		else if (EncryptionItemCount >= EncryptionIoRequestCount)
+			EncryptionItemCount = EncryptionIoRequestCount - 1;
+
+		/* EncryptionFragmentSize value in registry is expressed in KiB */
+		if (EncryptionFragmentSize == 0)
+			EncryptionFragmentSize = TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE / 1024;
+		else if (EncryptionFragmentSize > (8 * TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE / 1024))
+			EncryptionFragmentSize = 8 * TC_ENC_IO_QUEUE_MAX_FRAGMENT_SIZE / 1024;
+		
+		EncryptionFragmentSize = EncryptionFragmentSize * 1024;
+	}
+
+
 	return status;
 }
 

src/Driver/Ntdriver.h

@@ -125,6 +125,9 @@ extern BOOL CacheBootPassword;
 extern BOOL CacheBootPim;
 extern BOOL BlockSystemTrimCommand;
 extern BOOL AllowWindowsDefrag;
+extern int EncryptionIoRequestCount;
+extern int EncryptionItemCount;
+extern int EncryptionFragmentSize;
 /* Helper macro returning x seconds in units of 100 nanoseconds */
 #define WAIT_SECONDS(x) ((x)*10000000)