This patch rework XenStoreProcessMessage in order to avoid memory
allocation when a reply is expected. Instead of allocating a buffer
for this reply, we are going to copy to a buffer passed by the caller.
For messages that aren't fully received, they will be stored in a
buffer that have been allocated at the initialisation of the driver.
A temporary memory allocation is made in XenStoreTalkv but that will
be removed in a further patch.
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2190
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---
OvmfPkg/XenBusDxe/XenStore.c | 297 +++++++++++++++--------------------
1 file changed, 130 insertions(+), 167 deletions(-)
diff --git a/OvmfPkg/XenBusDxe/XenStore.c b/OvmfPkg/XenBusDxe/XenStore.c
index ca7be12d68..004d3b6022 100644
--- a/OvmfPkg/XenBusDxe/XenStore.c
+++ b/OvmfPkg/XenBusDxe/XenStore.c
@@ -72,27 +72,6 @@ struct _XENSTORE_WATCH
#define XENSTORE_WATCH_FROM_LINK(l) \
CR (l, XENSTORE_WATCH, Link, XENSTORE_WATCH_SIGNATURE)
-
-/**
- * Structure capturing messages received from the XenStore service.
- */
-#define XENSTORE_MESSAGE_SIGNATURE SIGNATURE_32 ('X', 'S', 's', 'm')
-typedef struct {
- UINT32 Signature;
- LIST_ENTRY Link;
-
- struct xsd_sockmsg Header;
-
- union {
- /* Queued replies. */
- struct {
- CHAR8 *Body;
- } Reply;
- } u;
-} XENSTORE_MESSAGE;
-#define XENSTORE_MESSAGE_FROM_LINK(r) \
- CR (r, XENSTORE_MESSAGE, Link, XENSTORE_MESSAGE_SIGNATURE)
-
/**
* Container for all XenStore related state.
*/
@@ -105,21 +84,6 @@ typedef struct {
XENBUS_DEVICE *Dev;
- /**
- * A list of replies to our requests.
- *
- * The reply list is filled by xs_rcv_thread(). It
- * is consumed by the context that issued the request
- * to which a reply is made. The requester blocks in
- * XenStoreReadReply ().
- *
- * /note Only one requesting context can be active at a time.
- */
- LIST_ENTRY ReplyList;
-
- /** Lock protecting the reply list. */
- EFI_LOCK ReplyLock;
-
/**
* List of registered watches.
*/
@@ -136,6 +100,13 @@ typedef struct {
/** Handle for XenStore events. */
EFI_EVENT EventChannelEvent;
+
+ /** Buffer used to copy payloads from the xenstore ring */
+ // The + 1 is to allow to have a \0.
+ CHAR8 Buffer[XENSTORE_PAYLOAD_MAX + 1];
+
+ /** ID used when sending messages to xenstored */
+ UINTN NextRequestId;
} XENSTORE_PRIVATE;
//
@@ -148,6 +119,12 @@ static XENSTORE_PRIVATE xs;
// Private Utility Functions
//
+STATIC
+XENSTORE_STATUS
+XenStoreGetError (
+ CONST CHAR8 *ErrorStr
+ );
+
/**
Count and optionally record pointers to a number of NUL terminated
strings in a buffer.
@@ -613,70 +590,106 @@ XenStoreReadStore (
Block reading the next message from the XenStore service and
process the result.
+ @param ExpectedRequestId Block until a reply to with this ID is seen.
+ @param ExpectedTransactionId Idem, but should also match this ID.
+ @param BufferSize IN: size of the buffer
+ OUT: The returned length of the reply.
+ @param Buffer The returned body of the reply.
+
@return XENSTORE_STATUS_SUCCESS on success. Otherwise an errno value
indicating the type of failure encountered.
**/
STATIC
XENSTORE_STATUS
XenStoreProcessMessage (
- VOID
+ IN UINT32 ExpectedRequestId,
+ IN UINT32 ExpectedTransactionId,
+ IN OUT UINTN *BufferSize OPTIONAL,
+ IN OUT CHAR8 *Buffer OPTIONAL
)
{
- XENSTORE_MESSAGE *Message;
- CHAR8 *Body;
- XENSTORE_STATUS Status;
-
- Message = AllocateZeroPool (sizeof (XENSTORE_MESSAGE));
- Message->Signature = XENSTORE_MESSAGE_SIGNATURE;
- Status = XenStoreReadStore (&Message->Header, sizeof (Message->Header));
- if (Status != XENSTORE_STATUS_SUCCESS) {
- FreePool (Message);
- DEBUG ((EFI_D_ERROR, "XenStore: Error read store (%d)\n", Status));
- return Status;
- }
-
- Body = AllocatePool (Message->Header.len + 1);
- Status = XenStoreReadStore (Body, Message->Header.len);
- if (Status != XENSTORE_STATUS_SUCCESS) {
- FreePool (Body);
- FreePool (Message);
- DEBUG ((EFI_D_ERROR, "XenStore: Error read store (%d)\n", Status));
- return Status;
- }
- Body[Message->Header.len] = '\0';
+ struct xsd_sockmsg Header;
+ CHAR8 *Payload;
+ XENSTORE_STATUS Status;
- if (Message->Header.type == XS_WATCH_EVENT) {
- CONST CHAR8 *WatchEventPath;
- CONST CHAR8 *WatchEventToken;
- VOID *ConvertedToken;
- XENSTORE_WATCH *Watch;
+ while (TRUE) {
- //
- // Parse WATCH_EVENT messages
- // <path>\0<token>\0
- //
- WatchEventPath = Body;
- WatchEventToken = WatchEventPath + AsciiStrSize (WatchEventPath);
+ Status = XenStoreReadStore (&Header, sizeof (Header));
+ if (Status != XENSTORE_STATUS_SUCCESS) {
+ DEBUG ((DEBUG_ERROR, "XenStore: Error read store (%d)\n", Status));
+ return Status;
+ }
- ConvertedToken = (VOID *) AsciiStrHexToUintn (WatchEventToken);
+ ASSERT (Header.len <= XENSTORE_PAYLOAD_MAX);
+ if (Header.len > XENSTORE_PAYLOAD_MAX) {
+ DEBUG ((DEBUG_ERROR, "XenStore: Message payload over %d (is %d)\n",
+ XENSTORE_PAYLOAD_MAX, Header.len));
+ Header.len = XENSTORE_PAYLOAD_MAX;
+ }
- EfiAcquireLock (&xs.RegisteredWatchesLock);
- Watch = XenStoreFindWatch (ConvertedToken);
- DEBUG ((DEBUG_INFO, "XenStore: Watch event %a\n", WatchEventToken));
- if (Watch != NULL) {
- Watch->Triggered = TRUE;
- } else {
- DEBUG ((EFI_D_WARN, "XenStore: Watch handle %a not found\n",
- WatchEventToken));
+ Payload = xs.Buffer;
+ Status = XenStoreReadStore (Payload, Header.len);
+ if (Status != XENSTORE_STATUS_SUCCESS) {
+ DEBUG ((DEBUG_ERROR, "XenStore: Error read store (%d)\n", Status));
+ return Status;
}
- EfiReleaseLock (&xs.RegisteredWatchesLock);
- FreePool (Message);
- FreePool (Body);
- } else {
- Message->u.Reply.Body = Body;
- EfiAcquireLock (&xs.ReplyLock);
- InsertTailList (&xs.ReplyList, &Message->Link);
- EfiReleaseLock (&xs.ReplyLock);
+ Payload[Header.len] = '\0';
+
+ if (Header.type == XS_WATCH_EVENT) {
+ CONST CHAR8 *WatchEventPath;
+ CONST CHAR8 *WatchEventToken;
+ VOID *ConvertedToken;
+ XENSTORE_WATCH *Watch;
+
+ //
+ // Parse WATCH_EVENT messages
+ // <path>\0<token>\0
+ //
+ WatchEventPath = Payload;
+ WatchEventToken = WatchEventPath + AsciiStrSize (WatchEventPath);
+
+ ConvertedToken = (VOID *) AsciiStrHexToUintn (WatchEventToken);
+
+ EfiAcquireLock (&xs.RegisteredWatchesLock);
+ Watch = XenStoreFindWatch (ConvertedToken);
+ DEBUG ((DEBUG_INFO, "XenStore: Watch event %a\n", WatchEventToken));
+ if (Watch != NULL) {
+ Watch->Triggered = TRUE;
+ } else {
+ DEBUG ((DEBUG_WARN, "XenStore: Watch handle %a not found\n",
+ WatchEventToken));
+ }
+ EfiReleaseLock (&xs.RegisteredWatchesLock);
+
+ if (Header.req_id == ExpectedRequestId
+ && Header.tx_id == ExpectedTransactionId
+ && Buffer == NULL) {
+ //
+ // We were waiting for a watch event
+ //
+ return XENSTORE_STATUS_SUCCESS;
+ }
+ } else if (Header.req_id == ExpectedRequestId
+ && Header.tx_id == ExpectedTransactionId) {
+ Status = XENSTORE_STATUS_SUCCESS;
+ if (Header.type == XS_ERROR) {
+ Status = XenStoreGetError (Payload);
+ } else if (Buffer != NULL) {
+ ASSERT (BufferSize != NULL);
+ ASSERT (*BufferSize >= Header.len);
+ CopyMem (Buffer, Payload, MIN (Header.len + 1, *BufferSize));
+ *BufferSize = Header.len;
+ } else {
+ //
+ // Payload should be "OK" if the function sending a request doesn't
+ // expect a reply.
+ //
+ ASSERT (Header.len == 3);
+ ASSERT (AsciiStrCmp (Payload, "OK") == 0);
+ }
+ return Status;
+ }
+
}
return XENSTORE_STATUS_SUCCESS;
@@ -736,51 +749,6 @@ XenStoreGetError (
return XENSTORE_STATUS_EINVAL;
}
-/**
- Block waiting for a reply to a message request.
-
- @param TypePtr The returned type of the reply.
- @param LenPtr The returned body length of the reply.
- @param Result The returned body of the reply.
-**/
-STATIC
-XENSTORE_STATUS
-XenStoreReadReply (
- OUT enum xsd_sockmsg_type *TypePtr,
- OUT UINT32 *LenPtr OPTIONAL,
- OUT VOID **Result
- )
-{
- XENSTORE_MESSAGE *Message;
- LIST_ENTRY *Entry;
- CHAR8 *Body;
-
- while (IsListEmpty (&xs.ReplyList)) {
- XENSTORE_STATUS Status;
- Status = XenStoreProcessMessage ();
- if (Status != XENSTORE_STATUS_SUCCESS && Status != XENSTORE_STATUS_EAGAIN) {
- DEBUG ((DEBUG_ERROR, "XenStore, error while reading the ring (%d).\n",
- Status));
- return Status;
- }
- }
- EfiAcquireLock (&xs.ReplyLock);
- Entry = GetFirstNode (&xs.ReplyList);
- Message = XENSTORE_MESSAGE_FROM_LINK (Entry);
- RemoveEntryList (Entry);
- EfiReleaseLock (&xs.ReplyLock);
-
- *TypePtr = Message->Header.type;
- if (LenPtr != NULL) {
- *LenPtr = Message->Header.len;
- }
- Body = Message->u.Reply.Body;
-
- FreePool (Message);
- *Result = Body;
- return XENSTORE_STATUS_SUCCESS;
-}
-
/**
Send a message with an optionally muti-part body to the XenStore service.
@@ -806,16 +774,17 @@ XenStoreTalkv (
)
{
struct xsd_sockmsg Message;
- void *Return = NULL;
- UINT32 Index;
- XENSTORE_STATUS Status;
+ UINTN Index;
+ XENSTORE_STATUS Status;
+ VOID *Buffer;
+ UINTN BufferSize;
if (Transaction == XST_NIL) {
Message.tx_id = 0;
} else {
Message.tx_id = Transaction->Id;
}
- Message.req_id = 0;
+ Message.req_id = xs.NextRequestId++;
Message.type = RequestType;
Message.len = 0;
for (Index = 0; Index < NumRequests; Index++) {
@@ -836,29 +805,36 @@ XenStoreTalkv (
}
}
- Status = XenStoreReadReply ((enum xsd_sockmsg_type *)&Message.type, LenPtr, &Return);
-
-Error:
- if (Status != XENSTORE_STATUS_SUCCESS) {
- return Status;
+ if (ResultPtr) {
+ Buffer = AllocatePool (XENSTORE_PAYLOAD_MAX + 1);
+ BufferSize = XENSTORE_PAYLOAD_MAX;
+ } else {
+ Buffer = NULL;
+ BufferSize = 0;
}
- if (Message.type == XS_ERROR) {
- Status = XenStoreGetError (Return);
- FreePool (Return);
+ //
+ // Wait for a reply to our request
+ //
+ Status = XenStoreProcessMessage (Message.req_id, Message.tx_id,
+ &BufferSize, Buffer);
+
+ if (Status != XENSTORE_STATUS_SUCCESS) {
+ DEBUG ((DEBUG_ERROR, "XenStore, error while reading the ring (%d).\n",
+ Status));
+ FreePool (Buffer);
return Status;
}
- /* Reply is either error or an echo of our request message type. */
- ASSERT ((enum xsd_sockmsg_type)Message.type == RequestType);
-
if (ResultPtr) {
- *ResultPtr = Return;
- } else {
- FreePool (Return);
+ *ResultPtr = Buffer;
+ if (LenPtr) {
+ *LenPtr = BufferSize;
+ }
}
- return XENSTORE_STATUS_SUCCESS;
+Error:
+ return Status;
}
/**
@@ -975,7 +951,7 @@ XenStoreWaitWatch (
return XENSTORE_STATUS_SUCCESS;
}
- Status = XenStoreProcessMessage ();
+ Status = XenStoreProcessMessage (0, 0, NULL, NULL);
if (Status != XENSTORE_STATUS_SUCCESS && Status != XENSTORE_STATUS_EAGAIN) {
return Status;
}
@@ -1060,12 +1036,12 @@ XenStoreInit (
DEBUG ((EFI_D_INFO, "XenBusInit: XenBus rings @%p, event channel %x\n",
xs.XenStore, xs.EventChannel));
- InitializeListHead (&xs.ReplyList);
InitializeListHead (&xs.RegisteredWatches);
- EfiInitializeLock (&xs.ReplyLock, TPL_NOTIFY);
EfiInitializeLock (&xs.RegisteredWatchesLock, TPL_NOTIFY);
+ xs.NextRequestId = 1;
+
/* Initialize the shared memory rings to talk to xenstored */
Status = XenStoreInitComms (&xs);
@@ -1095,19 +1071,6 @@ XenStoreDeinit (
}
}
- if (!IsListEmpty (&xs.ReplyList)) {
- XENSTORE_MESSAGE *Message;
- LIST_ENTRY *Entry;
- Entry = GetFirstNode (&xs.ReplyList);
- while (!IsNull (&xs.ReplyList, Entry)) {
- Message = XENSTORE_MESSAGE_FROM_LINK (Entry);
- Entry = GetNextNode (&xs.ReplyList, Entry);
- RemoveEntryList (&Message->Link);
- FreePool (Message->u.Reply.Body);
- FreePool (Message);
- }
- }
-
gBS->CloseEvent (xs.EventChannelEvent);
if (xs.XenStore->server_features & XENSTORE_SERVER_FEATURE_RECONNECTION) {
--
Anthony PERARD
-=-=-=-=-=-=-=-=-=-=-=-
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-=-=-=-=-=-=-=-=-=-=-=-
On 09/13/19 16:50, Anthony PERARD wrote:
> This patch rework XenStoreProcessMessage in order to avoid memory
> allocation when a reply is expected. Instead of allocating a buffer
> for this reply, we are going to copy to a buffer passed by the caller.
> For messages that aren't fully received, they will be stored in a
> buffer that have been allocated at the initialisation of the driver.
>
> A temporary memory allocation is made in XenStoreTalkv but that will
> be removed in a further patch.
>
> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2190
> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
> ---
> OvmfPkg/XenBusDxe/XenStore.c | 297 +++++++++++++++--------------------
> 1 file changed, 130 insertions(+), 167 deletions(-)
Sorry, too big for a detailed review, and I'd like to go through the
series today. So, based on the diffstat,
Acked-by: Laszlo Ersek <lersek@redhat.com>
Thanks
Laszlo
> diff --git a/OvmfPkg/XenBusDxe/XenStore.c b/OvmfPkg/XenBusDxe/XenStore.c
> index ca7be12d68..004d3b6022 100644
> --- a/OvmfPkg/XenBusDxe/XenStore.c
> +++ b/OvmfPkg/XenBusDxe/XenStore.c
> @@ -72,27 +72,6 @@ struct _XENSTORE_WATCH
> #define XENSTORE_WATCH_FROM_LINK(l) \
> CR (l, XENSTORE_WATCH, Link, XENSTORE_WATCH_SIGNATURE)
>
> -
> -/**
> - * Structure capturing messages received from the XenStore service.
> - */
> -#define XENSTORE_MESSAGE_SIGNATURE SIGNATURE_32 ('X', 'S', 's', 'm')
> -typedef struct {
> - UINT32 Signature;
> - LIST_ENTRY Link;
> -
> - struct xsd_sockmsg Header;
> -
> - union {
> - /* Queued replies. */
> - struct {
> - CHAR8 *Body;
> - } Reply;
> - } u;
> -} XENSTORE_MESSAGE;
> -#define XENSTORE_MESSAGE_FROM_LINK(r) \
> - CR (r, XENSTORE_MESSAGE, Link, XENSTORE_MESSAGE_SIGNATURE)
> -
> /**
> * Container for all XenStore related state.
> */
> @@ -105,21 +84,6 @@ typedef struct {
>
> XENBUS_DEVICE *Dev;
>
> - /**
> - * A list of replies to our requests.
> - *
> - * The reply list is filled by xs_rcv_thread(). It
> - * is consumed by the context that issued the request
> - * to which a reply is made. The requester blocks in
> - * XenStoreReadReply ().
> - *
> - * /note Only one requesting context can be active at a time.
> - */
> - LIST_ENTRY ReplyList;
> -
> - /** Lock protecting the reply list. */
> - EFI_LOCK ReplyLock;
> -
> /**
> * List of registered watches.
> */
> @@ -136,6 +100,13 @@ typedef struct {
>
> /** Handle for XenStore events. */
> EFI_EVENT EventChannelEvent;
> +
> + /** Buffer used to copy payloads from the xenstore ring */
> + // The + 1 is to allow to have a \0.
> + CHAR8 Buffer[XENSTORE_PAYLOAD_MAX + 1];
> +
> + /** ID used when sending messages to xenstored */
> + UINTN NextRequestId;
> } XENSTORE_PRIVATE;
>
> //
> @@ -148,6 +119,12 @@ static XENSTORE_PRIVATE xs;
> // Private Utility Functions
> //
>
> +STATIC
> +XENSTORE_STATUS
> +XenStoreGetError (
> + CONST CHAR8 *ErrorStr
> + );
> +
> /**
> Count and optionally record pointers to a number of NUL terminated
> strings in a buffer.
> @@ -613,70 +590,106 @@ XenStoreReadStore (
> Block reading the next message from the XenStore service and
> process the result.
>
> + @param ExpectedRequestId Block until a reply to with this ID is seen.
> + @param ExpectedTransactionId Idem, but should also match this ID.
> + @param BufferSize IN: size of the buffer
> + OUT: The returned length of the reply.
> + @param Buffer The returned body of the reply.
> +
> @return XENSTORE_STATUS_SUCCESS on success. Otherwise an errno value
> indicating the type of failure encountered.
> **/
> STATIC
> XENSTORE_STATUS
> XenStoreProcessMessage (
> - VOID
> + IN UINT32 ExpectedRequestId,
> + IN UINT32 ExpectedTransactionId,
> + IN OUT UINTN *BufferSize OPTIONAL,
> + IN OUT CHAR8 *Buffer OPTIONAL
> )
> {
> - XENSTORE_MESSAGE *Message;
> - CHAR8 *Body;
> - XENSTORE_STATUS Status;
> -
> - Message = AllocateZeroPool (sizeof (XENSTORE_MESSAGE));
> - Message->Signature = XENSTORE_MESSAGE_SIGNATURE;
> - Status = XenStoreReadStore (&Message->Header, sizeof (Message->Header));
> - if (Status != XENSTORE_STATUS_SUCCESS) {
> - FreePool (Message);
> - DEBUG ((EFI_D_ERROR, "XenStore: Error read store (%d)\n", Status));
> - return Status;
> - }
> -
> - Body = AllocatePool (Message->Header.len + 1);
> - Status = XenStoreReadStore (Body, Message->Header.len);
> - if (Status != XENSTORE_STATUS_SUCCESS) {
> - FreePool (Body);
> - FreePool (Message);
> - DEBUG ((EFI_D_ERROR, "XenStore: Error read store (%d)\n", Status));
> - return Status;
> - }
> - Body[Message->Header.len] = '\0';
> + struct xsd_sockmsg Header;
> + CHAR8 *Payload;
> + XENSTORE_STATUS Status;
>
> - if (Message->Header.type == XS_WATCH_EVENT) {
> - CONST CHAR8 *WatchEventPath;
> - CONST CHAR8 *WatchEventToken;
> - VOID *ConvertedToken;
> - XENSTORE_WATCH *Watch;
> + while (TRUE) {
>
> - //
> - // Parse WATCH_EVENT messages
> - // <path>\0<token>\0
> - //
> - WatchEventPath = Body;
> - WatchEventToken = WatchEventPath + AsciiStrSize (WatchEventPath);
> + Status = XenStoreReadStore (&Header, sizeof (Header));
> + if (Status != XENSTORE_STATUS_SUCCESS) {
> + DEBUG ((DEBUG_ERROR, "XenStore: Error read store (%d)\n", Status));
> + return Status;
> + }
>
> - ConvertedToken = (VOID *) AsciiStrHexToUintn (WatchEventToken);
> + ASSERT (Header.len <= XENSTORE_PAYLOAD_MAX);
> + if (Header.len > XENSTORE_PAYLOAD_MAX) {
> + DEBUG ((DEBUG_ERROR, "XenStore: Message payload over %d (is %d)\n",
> + XENSTORE_PAYLOAD_MAX, Header.len));
> + Header.len = XENSTORE_PAYLOAD_MAX;
> + }
>
> - EfiAcquireLock (&xs.RegisteredWatchesLock);
> - Watch = XenStoreFindWatch (ConvertedToken);
> - DEBUG ((DEBUG_INFO, "XenStore: Watch event %a\n", WatchEventToken));
> - if (Watch != NULL) {
> - Watch->Triggered = TRUE;
> - } else {
> - DEBUG ((EFI_D_WARN, "XenStore: Watch handle %a not found\n",
> - WatchEventToken));
> + Payload = xs.Buffer;
> + Status = XenStoreReadStore (Payload, Header.len);
> + if (Status != XENSTORE_STATUS_SUCCESS) {
> + DEBUG ((DEBUG_ERROR, "XenStore: Error read store (%d)\n", Status));
> + return Status;
> }
> - EfiReleaseLock (&xs.RegisteredWatchesLock);
> - FreePool (Message);
> - FreePool (Body);
> - } else {
> - Message->u.Reply.Body = Body;
> - EfiAcquireLock (&xs.ReplyLock);
> - InsertTailList (&xs.ReplyList, &Message->Link);
> - EfiReleaseLock (&xs.ReplyLock);
> + Payload[Header.len] = '\0';
> +
> + if (Header.type == XS_WATCH_EVENT) {
> + CONST CHAR8 *WatchEventPath;
> + CONST CHAR8 *WatchEventToken;
> + VOID *ConvertedToken;
> + XENSTORE_WATCH *Watch;
> +
> + //
> + // Parse WATCH_EVENT messages
> + // <path>\0<token>\0
> + //
> + WatchEventPath = Payload;
> + WatchEventToken = WatchEventPath + AsciiStrSize (WatchEventPath);
> +
> + ConvertedToken = (VOID *) AsciiStrHexToUintn (WatchEventToken);
> +
> + EfiAcquireLock (&xs.RegisteredWatchesLock);
> + Watch = XenStoreFindWatch (ConvertedToken);
> + DEBUG ((DEBUG_INFO, "XenStore: Watch event %a\n", WatchEventToken));
> + if (Watch != NULL) {
> + Watch->Triggered = TRUE;
> + } else {
> + DEBUG ((DEBUG_WARN, "XenStore: Watch handle %a not found\n",
> + WatchEventToken));
> + }
> + EfiReleaseLock (&xs.RegisteredWatchesLock);
> +
> + if (Header.req_id == ExpectedRequestId
> + && Header.tx_id == ExpectedTransactionId
> + && Buffer == NULL) {
> + //
> + // We were waiting for a watch event
> + //
> + return XENSTORE_STATUS_SUCCESS;
> + }
> + } else if (Header.req_id == ExpectedRequestId
> + && Header.tx_id == ExpectedTransactionId) {
> + Status = XENSTORE_STATUS_SUCCESS;
> + if (Header.type == XS_ERROR) {
> + Status = XenStoreGetError (Payload);
> + } else if (Buffer != NULL) {
> + ASSERT (BufferSize != NULL);
> + ASSERT (*BufferSize >= Header.len);
> + CopyMem (Buffer, Payload, MIN (Header.len + 1, *BufferSize));
> + *BufferSize = Header.len;
> + } else {
> + //
> + // Payload should be "OK" if the function sending a request doesn't
> + // expect a reply.
> + //
> + ASSERT (Header.len == 3);
> + ASSERT (AsciiStrCmp (Payload, "OK") == 0);
> + }
> + return Status;
> + }
> +
> }
>
> return XENSTORE_STATUS_SUCCESS;
> @@ -736,51 +749,6 @@ XenStoreGetError (
> return XENSTORE_STATUS_EINVAL;
> }
>
> -/**
> - Block waiting for a reply to a message request.
> -
> - @param TypePtr The returned type of the reply.
> - @param LenPtr The returned body length of the reply.
> - @param Result The returned body of the reply.
> -**/
> -STATIC
> -XENSTORE_STATUS
> -XenStoreReadReply (
> - OUT enum xsd_sockmsg_type *TypePtr,
> - OUT UINT32 *LenPtr OPTIONAL,
> - OUT VOID **Result
> - )
> -{
> - XENSTORE_MESSAGE *Message;
> - LIST_ENTRY *Entry;
> - CHAR8 *Body;
> -
> - while (IsListEmpty (&xs.ReplyList)) {
> - XENSTORE_STATUS Status;
> - Status = XenStoreProcessMessage ();
> - if (Status != XENSTORE_STATUS_SUCCESS && Status != XENSTORE_STATUS_EAGAIN) {
> - DEBUG ((DEBUG_ERROR, "XenStore, error while reading the ring (%d).\n",
> - Status));
> - return Status;
> - }
> - }
> - EfiAcquireLock (&xs.ReplyLock);
> - Entry = GetFirstNode (&xs.ReplyList);
> - Message = XENSTORE_MESSAGE_FROM_LINK (Entry);
> - RemoveEntryList (Entry);
> - EfiReleaseLock (&xs.ReplyLock);
> -
> - *TypePtr = Message->Header.type;
> - if (LenPtr != NULL) {
> - *LenPtr = Message->Header.len;
> - }
> - Body = Message->u.Reply.Body;
> -
> - FreePool (Message);
> - *Result = Body;
> - return XENSTORE_STATUS_SUCCESS;
> -}
> -
> /**
> Send a message with an optionally muti-part body to the XenStore service.
>
> @@ -806,16 +774,17 @@ XenStoreTalkv (
> )
> {
> struct xsd_sockmsg Message;
> - void *Return = NULL;
> - UINT32 Index;
> - XENSTORE_STATUS Status;
> + UINTN Index;
> + XENSTORE_STATUS Status;
> + VOID *Buffer;
> + UINTN BufferSize;
>
> if (Transaction == XST_NIL) {
> Message.tx_id = 0;
> } else {
> Message.tx_id = Transaction->Id;
> }
> - Message.req_id = 0;
> + Message.req_id = xs.NextRequestId++;
> Message.type = RequestType;
> Message.len = 0;
> for (Index = 0; Index < NumRequests; Index++) {
> @@ -836,29 +805,36 @@ XenStoreTalkv (
> }
> }
>
> - Status = XenStoreReadReply ((enum xsd_sockmsg_type *)&Message.type, LenPtr, &Return);
> -
> -Error:
> - if (Status != XENSTORE_STATUS_SUCCESS) {
> - return Status;
> + if (ResultPtr) {
> + Buffer = AllocatePool (XENSTORE_PAYLOAD_MAX + 1);
> + BufferSize = XENSTORE_PAYLOAD_MAX;
> + } else {
> + Buffer = NULL;
> + BufferSize = 0;
> }
>
> - if (Message.type == XS_ERROR) {
> - Status = XenStoreGetError (Return);
> - FreePool (Return);
> + //
> + // Wait for a reply to our request
> + //
> + Status = XenStoreProcessMessage (Message.req_id, Message.tx_id,
> + &BufferSize, Buffer);
> +
> + if (Status != XENSTORE_STATUS_SUCCESS) {
> + DEBUG ((DEBUG_ERROR, "XenStore, error while reading the ring (%d).\n",
> + Status));
> + FreePool (Buffer);
> return Status;
> }
>
> - /* Reply is either error or an echo of our request message type. */
> - ASSERT ((enum xsd_sockmsg_type)Message.type == RequestType);
> -
> if (ResultPtr) {
> - *ResultPtr = Return;
> - } else {
> - FreePool (Return);
> + *ResultPtr = Buffer;
> + if (LenPtr) {
> + *LenPtr = BufferSize;
> + }
> }
>
> - return XENSTORE_STATUS_SUCCESS;
> +Error:
> + return Status;
> }
>
> /**
> @@ -975,7 +951,7 @@ XenStoreWaitWatch (
> return XENSTORE_STATUS_SUCCESS;
> }
>
> - Status = XenStoreProcessMessage ();
> + Status = XenStoreProcessMessage (0, 0, NULL, NULL);
> if (Status != XENSTORE_STATUS_SUCCESS && Status != XENSTORE_STATUS_EAGAIN) {
> return Status;
> }
> @@ -1060,12 +1036,12 @@ XenStoreInit (
> DEBUG ((EFI_D_INFO, "XenBusInit: XenBus rings @%p, event channel %x\n",
> xs.XenStore, xs.EventChannel));
>
> - InitializeListHead (&xs.ReplyList);
> InitializeListHead (&xs.RegisteredWatches);
>
> - EfiInitializeLock (&xs.ReplyLock, TPL_NOTIFY);
> EfiInitializeLock (&xs.RegisteredWatchesLock, TPL_NOTIFY);
>
> + xs.NextRequestId = 1;
> +
> /* Initialize the shared memory rings to talk to xenstored */
> Status = XenStoreInitComms (&xs);
>
> @@ -1095,19 +1071,6 @@ XenStoreDeinit (
> }
> }
>
> - if (!IsListEmpty (&xs.ReplyList)) {
> - XENSTORE_MESSAGE *Message;
> - LIST_ENTRY *Entry;
> - Entry = GetFirstNode (&xs.ReplyList);
> - while (!IsNull (&xs.ReplyList, Entry)) {
> - Message = XENSTORE_MESSAGE_FROM_LINK (Entry);
> - Entry = GetNextNode (&xs.ReplyList, Entry);
> - RemoveEntryList (&Message->Link);
> - FreePool (Message->u.Reply.Body);
> - FreePool (Message);
> - }
> - }
> -
> gBS->CloseEvent (xs.EventChannelEvent);
>
> if (xs.XenStore->server_features & XENSTORE_SERVER_FEATURE_RECONNECTION) {
>
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