2 Low-level kernel interface to the XenStore.
4 The XenStore interface is a simple storage system that is a means of
5 communicating state and configuration data between the Xen Domain 0
6 and the various guest domains. All configuration data other than
7 a small amount of essential information required during the early
8 boot process of launching a Xen aware guest, is managed using the
11 The XenStore is ASCII string based, and has a structure and semantics
12 similar to a filesystem. There are files and directories, the directories
13 able to contain files or other directories. The depth of the hierarchy
14 is only limited by the XenStore's maximum path length.
16 The communication channel between the XenStore service and other
17 domains is via two, guest specific, ring buffers in a shared memory
18 area. One ring buffer is used for communicating in each direction.
19 The grant table references for this shared memory are given to the
20 guest either via the xen_start_info structure for a fully para-
21 virtualized guest, or via HVM hypercalls for a hardware virtualized
24 The XenStore communication relies on an event channel and thus
25 interrupts. But under OVMF this XenStore client will pull the
26 state of the event channel.
28 Several Xen services depend on the XenStore, most notably the
29 XenBus used to discover and manage Xen devices.
31 Copyright (C) 2005 Rusty Russell, IBM Corporation
32 Copyright (C) 2009,2010 Spectra Logic Corporation
33 Copyright (C) 2014, Citrix Ltd.
35 This file may be distributed separately from the Linux kernel, or
36 incorporated into other software packages, subject to the following license:
38 Permission is hereby granted, free of charge, to any person obtaining a copy
39 of this source file (the "Software"), to deal in the Software without
40 restriction, including without limitation the rights to use, copy, modify,
41 merge, publish, distribute, sublicense, and/or sell copies of the Software,
42 and to permit persons to whom the Software is furnished to do so, subject to
43 the following conditions:
45 The above copyright notice and this permission notice shall be included in
46 all copies or substantial portions of the Software.
48 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
49 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
50 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
51 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
52 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
53 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
59 #include <Library/PrintLib.h>
61 #include <IndustryStandard/Xen/hvm/params.h>
63 #include "EventChannel.h"
64 #include <Library/XenHypercallLib.h>
67 // Private Data Structures
75 /* Register callback to watch subtree (node) in the XenStore. */
76 #define XENSTORE_WATCH_SIGNATURE SIGNATURE_32 ('X','S','w','a')
77 struct _XENSTORE_WATCH
82 /* Path being watched. */
86 #define XENSTORE_WATCH_FROM_LINK(l) \
87 CR (l, XENSTORE_WATCH, Link, XENSTORE_WATCH_SIGNATURE)
91 * Structure capturing messages received from the XenStore service.
93 #define XENSTORE_MESSAGE_SIGNATURE SIGNATURE_32 ('X', 'S', 's', 'm')
98 struct xsd_sockmsg Header
;
101 /* Queued replies. */
106 /* Queued watch events. */
108 XENSTORE_WATCH
*Handle
;
109 CONST CHAR8
**Vector
;
114 #define XENSTORE_MESSAGE_FROM_LINK(r) \
115 CR (r, XENSTORE_MESSAGE, Link, XENSTORE_MESSAGE_SIGNATURE)
118 * Container for all XenStore related state.
122 * Pointer to shared memory communication structures allowing us
123 * to communicate with the XenStore service.
125 struct xenstore_domain_interface
*XenStore
;
130 * A list of replies to our requests.
132 * The reply list is filled by xs_rcv_thread(). It
133 * is consumed by the context that issued the request
134 * to which a reply is made. The requester blocks in
135 * XenStoreReadReply ().
137 * /note Only one requesting context can be active at a time.
139 LIST_ENTRY ReplyList
;
141 /** Lock protecting the reply list. */
145 * List of registered watches.
147 LIST_ENTRY RegisteredWatches
;
149 /** Lock protecting the registered watches list. */
150 EFI_LOCK RegisteredWatchesLock
;
153 * List of pending watch callback events.
155 LIST_ENTRY WatchEvents
;
157 /** Lock protecting the watch calback list. */
158 EFI_LOCK WatchEventsLock
;
161 * The event channel for communicating with the
164 evtchn_port_t EventChannel
;
166 /** Handle for XenStore events. */
167 EFI_EVENT EventChannelEvent
;
173 static XENSTORE_PRIVATE xs
;
177 // Private Utility Functions
181 Count and optionally record pointers to a number of NUL terminated
184 @param Strings A pointer to a contiguous buffer of NUL terminated strings.
185 @param Len The length of the buffer pointed to by strings.
186 @param Dst An array to store pointers to each string found in strings.
188 @return A count of the number of strings found.
193 IN CONST CHAR8
*Strings
,
195 OUT CONST CHAR8
**Dst OPTIONAL
201 for (Ptr
= Strings
; Ptr
< Strings
+ Len
; Ptr
+= AsciiStrSize (Ptr
)) {
212 Convert a contiguous buffer containing a series of NUL terminated
213 strings into an array of pointers to strings.
215 The returned pointer references the array of string pointers which
216 is followed by the storage for the string data. It is the client's
217 responsibility to free this storage.
219 The storage addressed by Strings is free'd prior to Split returning.
221 @param Strings A pointer to a contiguous buffer of NUL terminated strings.
222 @param Len The length of the buffer pointed to by strings.
223 @param NumPtr The number of strings found and returned in the strings
226 @return An array of pointers to the strings found in the input buffer.
238 ASSERT(NumPtr
!= NULL
);
239 ASSERT(Strings
!= NULL
);
241 /* Protect against unterminated buffers. */
243 Strings
[Len
- 1] = '\0';
246 /* Count the Strings. */
247 *NumPtr
= ExtractStrings (Strings
, Len
, NULL
);
249 /* Transfer to one big alloc for easy freeing by the caller. */
250 Dst
= AllocatePool (*NumPtr
* sizeof (CHAR8
*) + Len
);
251 CopyMem ((VOID
*)&Dst
[*NumPtr
], Strings
, Len
);
254 /* Extract pointers to newly allocated array. */
255 Strings
= (CHAR8
*) &Dst
[*NumPtr
];
256 ExtractStrings (Strings
, Len
, Dst
);
262 Convert from watch token (unique identifier) to the associated
263 internal tracking structure for this watch.
265 @param Tocken The unique identifier for the watch to find.
267 @return A pointer to the found watch structure or NULL.
272 IN CONST CHAR8
*Token
275 XENSTORE_WATCH
*Watch
, *WantedWatch
;
278 WantedWatch
= (VOID
*) AsciiStrHexToUintn (Token
);
280 if (IsListEmpty (&xs
.RegisteredWatches
)) {
283 for (Entry
= GetFirstNode (&xs
.RegisteredWatches
);
284 !IsNull (&xs
.RegisteredWatches
, Entry
);
285 Entry
= GetNextNode (&xs
.RegisteredWatches
, Entry
)) {
286 Watch
= XENSTORE_WATCH_FROM_LINK (Entry
);
287 if (Watch
== WantedWatch
)
295 // Public Utility Functions
296 // API comments for these methods can be found in XenStore.h
301 IN CONST CHAR8
*DirectoryPath
,
308 /* +1 for '/' and +1 for '\0' */
309 BufSize
= AsciiStrLen (DirectoryPath
) + AsciiStrLen (Node
) + 2;
310 Buf
= AllocatePool (BufSize
);
311 ASSERT (Buf
!= NULL
);
313 if (Node
[0] == '\0') {
314 AsciiSPrint (Buf
, BufSize
, "%a", DirectoryPath
);
316 AsciiSPrint (Buf
, BufSize
, "%a/%a", DirectoryPath
, Node
);
323 // Low Level Communication Management
327 Verify that the indexes for a ring are valid.
329 The difference between the producer and consumer cannot
330 exceed the size of the ring.
332 @param Cons The consumer index for the ring to test.
333 @param Prod The producer index for the ring to test.
335 @retval TRUE If indexes are in range.
336 @retval FALSE If the indexes are out of range.
340 XenStoreCheckIndexes (
341 XENSTORE_RING_IDX Cons
,
342 XENSTORE_RING_IDX Prod
345 return ((Prod
- Cons
) <= XENSTORE_RING_SIZE
);
349 Return a pointer to, and the length of, the contiguous
350 free region available for output in a ring buffer.
352 @param Cons The consumer index for the ring.
353 @param Prod The producer index for the ring.
354 @param Buffer The base address of the ring's storage.
355 @param LenPtr The amount of contiguous storage available.
357 @return A pointer to the start location of the free region.
361 XenStoreGetOutputChunk (
362 IN XENSTORE_RING_IDX Cons
,
363 IN XENSTORE_RING_IDX Prod
,
369 Len
= XENSTORE_RING_SIZE
- MASK_XENSTORE_IDX (Prod
);
370 if ((XENSTORE_RING_SIZE
- (Prod
- Cons
)) < Len
) {
371 Len
= XENSTORE_RING_SIZE
- (Prod
- Cons
);
374 return (Buffer
+ MASK_XENSTORE_IDX (Prod
));
378 Return a pointer to, and the length of, the contiguous
379 data available to read from a ring buffer.
381 @param Cons The consumer index for the ring.
382 @param Prod The producer index for the ring.
383 @param Buffer The base address of the ring's storage.
384 @param LenPtr The amount of contiguous data available to read.
386 @return A pointer to the start location of the available data.
390 XenStoreGetInputChunk (
391 IN XENSTORE_RING_IDX Cons
,
392 IN XENSTORE_RING_IDX Prod
,
393 IN CONST CHAR8
*Buffer
,
399 Len
= XENSTORE_RING_SIZE
- MASK_XENSTORE_IDX (Cons
);
400 if ((Prod
- Cons
) < Len
) {
404 return (Buffer
+ MASK_XENSTORE_IDX (Cons
));
408 Wait for an event or timeout.
410 @param Event Event to wait for.
411 @param Timeout A timeout value in 100ns units.
413 @retval EFI_SUCCESS Event have been triggered or the current TPL is not
415 @retval EFI_TIMEOUT Timeout have expired.
419 XenStoreWaitForEvent (
426 EFI_EVENT TimerEvent
;
427 EFI_EVENT WaitList
[2];
429 gBS
->CreateEvent (EVT_TIMER
, 0, NULL
, NULL
, &TimerEvent
);
430 gBS
->SetTimer (TimerEvent
, TimerRelative
, Timeout
);
432 WaitList
[0] = xs
.EventChannelEvent
;
433 WaitList
[1] = TimerEvent
;
434 Status
= gBS
->WaitForEvent (2, WaitList
, &Index
);
435 ASSERT (Status
!= EFI_INVALID_PARAMETER
);
436 gBS
->CloseEvent (TimerEvent
);
437 if (Status
== EFI_UNSUPPORTED
) {
448 Transmit data to the XenStore service.
450 The buffer pointed to by DataPtr is at least Len bytes in length.
452 @param DataPtr A pointer to the contiguous data to send.
453 @param Len The amount of data to send.
455 @return On success 0, otherwise an errno value indicating the
461 IN CONST VOID
*DataPtr
,
465 XENSTORE_RING_IDX Cons
, Prod
;
466 CONST CHAR8
*Data
= (CONST CHAR8
*)DataPtr
;
472 Cons
= xs
.XenStore
->req_cons
;
473 Prod
= xs
.XenStore
->req_prod
;
474 if ((Prod
- Cons
) == XENSTORE_RING_SIZE
) {
476 * Output ring is full. Wait for a ring event.
478 * Note that the events from both queues are combined, so being woken
479 * does not guarantee that data exist in the read ring.
483 Status
= XenStoreWaitForEvent (xs
.EventChannelEvent
,
484 EFI_TIMER_PERIOD_SECONDS (1));
485 if (Status
== EFI_TIMEOUT
) {
486 DEBUG ((EFI_D_WARN
, "XenStore Write, waiting for a ring event.\n"));
491 /* Verify queue sanity. */
492 if (!XenStoreCheckIndexes (Cons
, Prod
)) {
493 xs
.XenStore
->req_cons
= xs
.XenStore
->req_prod
= 0;
494 return XENSTORE_STATUS_EIO
;
497 Dest
= XenStoreGetOutputChunk (Cons
, Prod
, xs
.XenStore
->req
, &Available
);
498 if (Available
> Len
) {
502 CopyMem (Dest
, Data
, Available
);
507 * The store to the producer index, which indicates
508 * to the other side that new data has arrived, must
509 * be visible only after our copy of the data into the
510 * ring has completed.
513 xs
.XenStore
->req_prod
+= Available
;
516 * The other side will see the change to req_prod at the time of the
520 XenEventChannelNotify (xs
.Dev
, xs
.EventChannel
);
523 return XENSTORE_STATUS_SUCCESS
;
527 Receive data from the XenStore service.
529 The buffer pointed to by DataPtr is at least Len bytes in length.
531 @param DataPtr A pointer to the contiguous buffer to receive the data.
532 @param Len The amount of data to receive.
534 @return On success 0, otherwise an errno value indicating the
544 XENSTORE_RING_IDX Cons
, Prod
;
545 CHAR8
*Data
= (CHAR8
*) DataPtr
;
551 Cons
= xs
.XenStore
->rsp_cons
;
552 Prod
= xs
.XenStore
->rsp_prod
;
555 * Nothing to read. Wait for a ring event.
557 * Note that the events from both queues are combined, so being woken
558 * does not guarantee that data exist in the read ring.
562 Status
= XenStoreWaitForEvent (xs
.EventChannelEvent
,
563 EFI_TIMER_PERIOD_SECONDS (1));
564 if (Status
== EFI_TIMEOUT
) {
565 DEBUG ((EFI_D_WARN
, "XenStore Read, waiting for a ring event.\n"));
570 /* Verify queue sanity. */
571 if (!XenStoreCheckIndexes (Cons
, Prod
)) {
572 xs
.XenStore
->rsp_cons
= xs
.XenStore
->rsp_prod
= 0;
573 return XENSTORE_STATUS_EIO
;
576 Src
= XenStoreGetInputChunk (Cons
, Prod
, xs
.XenStore
->rsp
, &Available
);
577 if (Available
> Len
) {
582 * Insure the data we read is related to the indexes
587 CopyMem (Data
, Src
, Available
);
592 * Insure that the producer of this ring does not see
593 * the ring space as free until after we have copied it
597 xs
.XenStore
->rsp_cons
+= Available
;
600 * The producer will see the updated consumer index when the event is
604 XenEventChannelNotify (xs
.Dev
, xs
.EventChannel
);
607 return XENSTORE_STATUS_SUCCESS
;
611 // Received Message Processing
615 Block reading the next message from the XenStore service and
618 @return XENSTORE_STATUS_SUCCESS on success. Otherwise an errno value
619 indicating the type of failure encountered.
623 XenStoreProcessMessage (
627 XENSTORE_MESSAGE
*Message
;
629 XENSTORE_STATUS Status
;
631 Message
= AllocateZeroPool (sizeof (XENSTORE_MESSAGE
));
632 Message
->Signature
= XENSTORE_MESSAGE_SIGNATURE
;
633 Status
= XenStoreReadStore (&Message
->Header
, sizeof (Message
->Header
));
634 if (Status
!= XENSTORE_STATUS_SUCCESS
) {
636 DEBUG ((EFI_D_ERROR
, "XenStore: Error read store (%d)\n", Status
));
640 Body
= AllocatePool (Message
->Header
.len
+ 1);
641 Status
= XenStoreReadStore (Body
, Message
->Header
.len
);
642 if (Status
!= XENSTORE_STATUS_SUCCESS
) {
645 DEBUG ((EFI_D_ERROR
, "XenStore: Error read store (%d)\n", Status
));
648 Body
[Message
->Header
.len
] = '\0';
650 if (Message
->Header
.type
== XS_WATCH_EVENT
) {
651 Message
->u
.Watch
.Vector
= Split(Body
, Message
->Header
.len
,
652 &Message
->u
.Watch
.VectorSize
);
654 EfiAcquireLock (&xs
.RegisteredWatchesLock
);
655 Message
->u
.Watch
.Handle
=
656 XenStoreFindWatch (Message
->u
.Watch
.Vector
[XS_WATCH_TOKEN
]);
657 DEBUG ((EFI_D_INFO
, "XenStore: Watch event %a\n",
658 Message
->u
.Watch
.Vector
[XS_WATCH_TOKEN
]));
659 if (Message
->u
.Watch
.Handle
!= NULL
) {
660 EfiAcquireLock (&xs
.WatchEventsLock
);
661 InsertHeadList (&xs
.WatchEvents
, &Message
->Link
);
662 EfiReleaseLock (&xs
.WatchEventsLock
);
664 DEBUG ((EFI_D_WARN
, "XenStore: Watch handle %a not found\n",
665 Message
->u
.Watch
.Vector
[XS_WATCH_TOKEN
]));
666 FreePool((VOID
*)Message
->u
.Watch
.Vector
);
669 EfiReleaseLock (&xs
.RegisteredWatchesLock
);
671 Message
->u
.Reply
.Body
= Body
;
672 EfiAcquireLock (&xs
.ReplyLock
);
673 InsertTailList (&xs
.ReplyList
, &Message
->Link
);
674 EfiReleaseLock (&xs
.ReplyLock
);
677 return XENSTORE_STATUS_SUCCESS
;
681 // XenStore Message Request/Reply Processing
685 Convert a XenStore error string into an errno number.
687 Unknown error strings are converted to EINVAL.
689 @param errorstring The error string to convert.
691 @return The errno best matching the input string.
695 XENSTORE_STATUS Status
;
696 CONST CHAR8
*ErrorStr
;
699 static XenStoreErrors gXenStoreErrors
[] = {
700 { XENSTORE_STATUS_EINVAL
, "EINVAL" },
701 { XENSTORE_STATUS_EACCES
, "EACCES" },
702 { XENSTORE_STATUS_EEXIST
, "EEXIST" },
703 { XENSTORE_STATUS_EISDIR
, "EISDIR" },
704 { XENSTORE_STATUS_ENOENT
, "ENOENT" },
705 { XENSTORE_STATUS_ENOMEM
, "ENOMEM" },
706 { XENSTORE_STATUS_ENOSPC
, "ENOSPC" },
707 { XENSTORE_STATUS_EIO
, "EIO" },
708 { XENSTORE_STATUS_ENOTEMPTY
, "ENOTEMPTY" },
709 { XENSTORE_STATUS_ENOSYS
, "ENOSYS" },
710 { XENSTORE_STATUS_EROFS
, "EROFS" },
711 { XENSTORE_STATUS_EBUSY
, "EBUSY" },
712 { XENSTORE_STATUS_EAGAIN
, "EAGAIN" },
713 { XENSTORE_STATUS_EISCONN
, "EISCONN" },
714 { XENSTORE_STATUS_E2BIG
, "E2BIG" }
720 CONST CHAR8
*ErrorStr
725 for (Index
= 0; Index
< ARRAY_SIZE(gXenStoreErrors
); Index
++) {
726 if (!AsciiStrCmp (ErrorStr
, gXenStoreErrors
[Index
].ErrorStr
)) {
727 return gXenStoreErrors
[Index
].Status
;
730 DEBUG ((EFI_D_WARN
, "XenStore gave unknown error %a\n", ErrorStr
));
731 return XENSTORE_STATUS_EINVAL
;
735 Block waiting for a reply to a message request.
737 @param TypePtr The returned type of the reply.
738 @param LenPtr The returned body length of the reply.
739 @param Result The returned body of the reply.
744 OUT
enum xsd_sockmsg_type
*TypePtr
,
745 OUT UINT32
*LenPtr OPTIONAL
,
749 XENSTORE_MESSAGE
*Message
;
753 while (IsListEmpty (&xs
.ReplyList
)) {
754 XENSTORE_STATUS Status
;
755 Status
= XenStoreProcessMessage ();
756 if (Status
!= XENSTORE_STATUS_SUCCESS
&& Status
!= XENSTORE_STATUS_EAGAIN
) {
757 DEBUG ((EFI_D_ERROR
, "XenStore, error while reading the ring (%d).",
762 EfiAcquireLock (&xs
.ReplyLock
);
763 Entry
= GetFirstNode (&xs
.ReplyList
);
764 Message
= XENSTORE_MESSAGE_FROM_LINK (Entry
);
765 RemoveEntryList (Entry
);
766 EfiReleaseLock (&xs
.ReplyLock
);
768 *TypePtr
= Message
->Header
.type
;
769 if (LenPtr
!= NULL
) {
770 *LenPtr
= Message
->Header
.len
;
772 Body
= Message
->u
.Reply
.Body
;
776 return XENSTORE_STATUS_SUCCESS
;
780 Send a message with an optionally muti-part body to the XenStore service.
782 @param Transaction The transaction to use for this request.
783 @param RequestType The type of message to send.
784 @param WriteRequest Pointers to the body sections of the request.
785 @param NumRequests The number of body sections in the request.
786 @param LenPtr The returned length of the reply.
787 @param ResultPtr The returned body of the reply.
789 @return XENSTORE_STATUS_SUCCESS on success. Otherwise an errno indicating
790 the cause of failure.
795 IN CONST XENSTORE_TRANSACTION
*Transaction
,
796 IN
enum xsd_sockmsg_type RequestType
,
797 IN CONST WRITE_REQUEST
*WriteRequest
,
798 IN UINT32 NumRequests
,
799 OUT UINT32
*LenPtr OPTIONAL
,
800 OUT VOID
**ResultPtr OPTIONAL
803 struct xsd_sockmsg Message
;
806 XENSTORE_STATUS Status
;
808 if (Transaction
== XST_NIL
) {
811 Message
.tx_id
= Transaction
->Id
;
814 Message
.type
= RequestType
;
816 for (Index
= 0; Index
< NumRequests
; Index
++) {
817 Message
.len
+= WriteRequest
[Index
].Len
;
820 Status
= XenStoreWriteStore (&Message
, sizeof (Message
));
821 if (Status
!= XENSTORE_STATUS_SUCCESS
) {
822 DEBUG ((EFI_D_ERROR
, "XenStoreTalkv failed %d\n", Status
));
826 for (Index
= 0; Index
< NumRequests
; Index
++) {
827 Status
= XenStoreWriteStore (WriteRequest
[Index
].Data
, WriteRequest
[Index
].Len
);
828 if (Status
!= XENSTORE_STATUS_SUCCESS
) {
829 DEBUG ((EFI_D_ERROR
, "XenStoreTalkv failed %d\n", Status
));
834 Status
= XenStoreReadReply ((enum xsd_sockmsg_type
*)&Message
.type
, LenPtr
, &Return
);
837 if (Status
!= XENSTORE_STATUS_SUCCESS
) {
841 if (Message
.type
== XS_ERROR
) {
842 Status
= XenStoreGetError (Return
);
847 /* Reply is either error or an echo of our request message type. */
848 ASSERT ((enum xsd_sockmsg_type
)Message
.type
== RequestType
);
856 return XENSTORE_STATUS_SUCCESS
;
860 Wrapper for XenStoreTalkv allowing easy transmission of a message with
861 a single, contiguous, message body.
863 The returned result is provided in malloced storage and thus must be free'd
866 @param Transaction The transaction to use for this request.
867 @param RequestType The type of message to send.
868 @param Body The body of the request.
869 @param LenPtr The returned length of the reply.
870 @param Result The returned body of the reply.
872 @return 0 on success. Otherwise an errno indicating
873 the cause of failure.
878 IN CONST XENSTORE_TRANSACTION
*Transaction
,
879 IN
enum xsd_sockmsg_type RequestType
,
880 IN CONST CHAR8
*Body
,
881 OUT UINT32
*LenPtr OPTIONAL
,
882 OUT VOID
**Result OPTIONAL
885 WRITE_REQUEST WriteRequest
;
887 WriteRequest
.Data
= (VOID
*) Body
;
888 WriteRequest
.Len
= (UINT32
)AsciiStrSize (Body
);
890 return XenStoreTalkv (Transaction
, RequestType
, &WriteRequest
, 1,
895 // XenStore Watch Support
899 Transmit a watch request to the XenStore service.
901 @param Path The path in the XenStore to watch.
902 @param Tocken A unique identifier for this watch.
904 @return XENSTORE_STATUS_SUCCESS on success. Otherwise an errno indicating the
914 WRITE_REQUEST WriteRequest
[2];
916 WriteRequest
[0].Data
= (VOID
*) Path
;
917 WriteRequest
[0].Len
= (UINT32
)AsciiStrSize (Path
);
918 WriteRequest
[1].Data
= (VOID
*) Token
;
919 WriteRequest
[1].Len
= (UINT32
)AsciiStrSize (Token
);
921 return XenStoreTalkv (XST_NIL
, XS_WATCH
, WriteRequest
, 2, NULL
, NULL
);
925 Transmit an uwatch request to the XenStore service.
927 @param Path The path in the XenStore to watch.
928 @param Tocken A unique identifier for this watch.
930 @return XENSTORE_STATUS_SUCCESS on success. Otherwise an errno indicating
931 the cause of failure.
940 WRITE_REQUEST WriteRequest
[2];
942 WriteRequest
[0].Data
= (VOID
*) Path
;
943 WriteRequest
[0].Len
= (UINT32
)AsciiStrSize (Path
);
944 WriteRequest
[1].Data
= (VOID
*) Token
;
945 WriteRequest
[1].Len
= (UINT32
)AsciiStrSize (Token
);
947 return XenStoreTalkv (XST_NIL
, XS_UNWATCH
, WriteRequest
, 2, NULL
, NULL
);
956 XENSTORE_MESSAGE
*Message
;
957 LIST_ENTRY
*Entry
= NULL
;
958 LIST_ENTRY
*Last
= NULL
;
959 XENSTORE_STATUS Status
;
962 EfiAcquireLock (&xs
.WatchEventsLock
);
963 if (IsListEmpty (&xs
.WatchEvents
) ||
964 Last
== GetFirstNode (&xs
.WatchEvents
)) {
965 EfiReleaseLock (&xs
.WatchEventsLock
);
966 Status
= XenStoreProcessMessage ();
967 if (Status
!= XENSTORE_STATUS_SUCCESS
&& Status
!= XENSTORE_STATUS_EAGAIN
) {
973 for (Entry
= GetFirstNode (&xs
.WatchEvents
);
974 Entry
!= Last
&& !IsNull (&xs
.WatchEvents
, Entry
);
975 Entry
= GetNextNode (&xs
.WatchEvents
, Entry
)) {
976 Message
= XENSTORE_MESSAGE_FROM_LINK (Entry
);
977 if (Message
->u
.Watch
.Handle
== Token
) {
978 RemoveEntryList (Entry
);
979 EfiReleaseLock (&xs
.WatchEventsLock
);
980 FreePool((VOID
*)Message
->u
.Watch
.Vector
);
982 return XENSTORE_STATUS_SUCCESS
;
985 Last
= GetFirstNode (&xs
.WatchEvents
);
986 EfiReleaseLock (&xs
.WatchEventsLock
);
992 NotifyEventChannelCheckForEvent (
997 XENSTORE_PRIVATE
*xsp
;
998 xsp
= (XENSTORE_PRIVATE
*)Context
;
999 if (TestAndClearBit (xsp
->EventChannel
, xsp
->Dev
->SharedInfo
->evtchn_pending
)) {
1000 gBS
->SignalEvent (Event
);
1005 Setup communication channels with the XenStore service.
1007 @retval EFI_SUCCESS if everything went well.
1012 XENSTORE_PRIVATE
*xsp
1016 EFI_EVENT TimerEvent
;
1017 struct xenstore_domain_interface
*XenStore
= xsp
->XenStore
;
1019 Status
= gBS
->CreateEvent (EVT_TIMER
, 0, NULL
, NULL
, &TimerEvent
);
1020 Status
= gBS
->SetTimer (TimerEvent
, TimerRelative
,
1021 EFI_TIMER_PERIOD_SECONDS (5));
1022 while (XenStore
->rsp_prod
!= XenStore
->rsp_cons
) {
1023 Status
= gBS
->CheckEvent (TimerEvent
);
1024 if (!EFI_ERROR (Status
)) {
1025 DEBUG ((EFI_D_WARN
, "XENSTORE response ring is not quiescent "
1026 "(%08x:%08x): fixing up\n",
1027 XenStore
->rsp_cons
, XenStore
->rsp_prod
));
1028 XenStore
->rsp_cons
= XenStore
->rsp_prod
;
1031 gBS
->CloseEvent (TimerEvent
);
1033 Status
= gBS
->CreateEvent (EVT_NOTIFY_WAIT
, TPL_NOTIFY
,
1034 NotifyEventChannelCheckForEvent
, xsp
,
1035 &xsp
->EventChannelEvent
);
1036 ASSERT_EFI_ERROR (Status
);
1042 Initialize XenStore.
1044 @param Dev A XENBUS_DEVICE instance.
1046 @retval EFI_SUCCESS if everything went well.
1055 * The HVM guest pseudo-physical frame number. This is Xen's mapping
1056 * of the true machine frame number into our "physical address space".
1062 xs
.EventChannel
= (evtchn_port_t
)XenHypercallHvmGetParam (HVM_PARAM_STORE_EVTCHN
);
1063 XenStoreGpfn
= (UINTN
)XenHypercallHvmGetParam (HVM_PARAM_STORE_PFN
);
1064 xs
.XenStore
= (VOID
*) (XenStoreGpfn
<< EFI_PAGE_SHIFT
);
1065 DEBUG ((EFI_D_INFO
, "XenBusInit: XenBus rings @%p, event channel %x\n",
1066 xs
.XenStore
, xs
.EventChannel
));
1068 InitializeListHead (&xs
.ReplyList
);
1069 InitializeListHead (&xs
.WatchEvents
);
1070 InitializeListHead (&xs
.RegisteredWatches
);
1072 EfiInitializeLock (&xs
.ReplyLock
, TPL_NOTIFY
);
1073 EfiInitializeLock (&xs
.RegisteredWatchesLock
, TPL_NOTIFY
);
1074 EfiInitializeLock (&xs
.WatchEventsLock
, TPL_NOTIFY
);
1076 /* Initialize the shared memory rings to talk to xenstored */
1077 Status
= XenStoreInitComms (&xs
);
1078 if (EFI_ERROR (Status
)) {
1087 IN XENBUS_DEVICE
*Dev
1091 // Emptying the list RegisteredWatches, but this list should already be
1092 // empty. Every driver that is using Watches should unregister them when
1095 if (!IsListEmpty (&xs
.RegisteredWatches
)) {
1096 XENSTORE_WATCH
*Watch
;
1098 DEBUG ((EFI_D_WARN
, "XenStore: RegisteredWatches is not empty, cleaning up..."));
1099 Entry
= GetFirstNode (&xs
.RegisteredWatches
);
1100 while (!IsNull (&xs
.RegisteredWatches
, Entry
)) {
1101 Watch
= XENSTORE_WATCH_FROM_LINK (Entry
);
1102 Entry
= GetNextNode (&xs
.RegisteredWatches
, Entry
);
1104 XenStoreUnregisterWatch (Watch
);
1109 // Emptying the list WatchEvents, but this list should already be empty after
1110 // having cleanup the list RegisteredWatches.
1112 if (!IsListEmpty (&xs
.WatchEvents
)) {
1114 DEBUG ((EFI_D_WARN
, "XenStore: WatchEvents is not empty, cleaning up..."));
1115 Entry
= GetFirstNode (&xs
.WatchEvents
);
1116 while (!IsNull (&xs
.WatchEvents
, Entry
)) {
1117 XENSTORE_MESSAGE
*Message
= XENSTORE_MESSAGE_FROM_LINK (Entry
);
1118 Entry
= GetNextNode (&xs
.WatchEvents
, Entry
);
1119 RemoveEntryList (&Message
->Link
);
1120 FreePool ((VOID
*)Message
->u
.Watch
.Vector
);
1125 if (!IsListEmpty (&xs
.ReplyList
)) {
1126 XENSTORE_MESSAGE
*Message
;
1128 Entry
= GetFirstNode (&xs
.ReplyList
);
1129 while (!IsNull (&xs
.ReplyList
, Entry
)) {
1130 Message
= XENSTORE_MESSAGE_FROM_LINK (Entry
);
1131 Entry
= GetNextNode (&xs
.ReplyList
, Entry
);
1132 RemoveEntryList (&Message
->Link
);
1133 FreePool (Message
->u
.Reply
.Body
);
1138 gBS
->CloseEvent (xs
.EventChannelEvent
);
1140 if (xs
.XenStore
->server_features
& XENSTORE_SERVER_FEATURE_RECONNECTION
) {
1141 xs
.XenStore
->connection
= XENSTORE_RECONNECT
;
1142 XenEventChannelNotify (xs
.Dev
, xs
.EventChannel
);
1143 while (*(volatile UINT32
*)&xs
.XenStore
->connection
== XENSTORE_RECONNECT
) {
1144 XenStoreWaitForEvent (xs
.EventChannelEvent
, EFI_TIMER_PERIOD_MILLISECONDS (100));
1147 /* If the backend reads the state while we're erasing it then the
1148 * ring state will become corrupted, preventing guest frontends from
1149 * connecting. This is rare. To help diagnose the failure, we fill
1150 * the ring with XS_INVALID packets. */
1151 SetMem (xs
.XenStore
->req
, XENSTORE_RING_SIZE
, 0xff);
1152 SetMem (xs
.XenStore
->rsp
, XENSTORE_RING_SIZE
, 0xff);
1153 xs
.XenStore
->req_cons
= xs
.XenStore
->req_prod
= 0;
1154 xs
.XenStore
->rsp_cons
= xs
.XenStore
->rsp_prod
= 0;
1161 // API comments for these methods can be found in XenStore.h
1165 XenStoreListDirectory (
1166 IN CONST XENSTORE_TRANSACTION
*Transaction
,
1167 IN CONST CHAR8
*DirectoryPath
,
1168 IN CONST CHAR8
*Node
,
1169 OUT UINT32
*DirectoryCountPtr
,
1170 OUT CONST CHAR8
***DirectoryListPtr
1176 XENSTORE_STATUS Status
;
1178 Path
= XenStoreJoin (DirectoryPath
, Node
);
1179 Status
= XenStoreSingle (Transaction
, XS_DIRECTORY
, Path
, &Len
,
1180 (VOID
**) &TempStr
);
1182 if (Status
!= XENSTORE_STATUS_SUCCESS
) {
1186 *DirectoryListPtr
= Split (TempStr
, Len
, DirectoryCountPtr
);
1188 return XENSTORE_STATUS_SUCCESS
;
1192 XenStorePathExists (
1193 IN CONST XENSTORE_TRANSACTION
*Transaction
,
1194 IN CONST CHAR8
*Directory
,
1195 IN CONST CHAR8
*Node
1198 CONST CHAR8
**TempStr
;
1199 XENSTORE_STATUS Status
;
1202 Status
= XenStoreListDirectory (Transaction
, Directory
, Node
,
1203 &TempNum
, &TempStr
);
1204 if (Status
!= XENSTORE_STATUS_SUCCESS
) {
1207 FreePool ((VOID
*)TempStr
);
1213 IN CONST XENSTORE_TRANSACTION
*Transaction
,
1214 IN CONST CHAR8
*DirectoryPath
,
1215 IN CONST CHAR8
*Node
,
1216 OUT UINT32
*LenPtr OPTIONAL
,
1222 XENSTORE_STATUS Status
;
1224 Path
= XenStoreJoin (DirectoryPath
, Node
);
1225 Status
= XenStoreSingle (Transaction
, XS_READ
, Path
, LenPtr
, &Value
);
1227 if (Status
!= XENSTORE_STATUS_SUCCESS
) {
1232 return XENSTORE_STATUS_SUCCESS
;
1237 IN CONST XENSTORE_TRANSACTION
*Transaction
,
1238 IN CONST CHAR8
*DirectoryPath
,
1239 IN CONST CHAR8
*Node
,
1244 WRITE_REQUEST WriteRequest
[2];
1245 XENSTORE_STATUS Status
;
1247 Path
= XenStoreJoin (DirectoryPath
, Node
);
1249 WriteRequest
[0].Data
= (VOID
*) Path
;
1250 WriteRequest
[0].Len
= (UINT32
)AsciiStrSize (Path
);
1251 WriteRequest
[1].Data
= (VOID
*) Str
;
1252 WriteRequest
[1].Len
= (UINT32
)AsciiStrLen (Str
);
1254 Status
= XenStoreTalkv (Transaction
, XS_WRITE
, WriteRequest
, 2, NULL
, NULL
);
1262 IN CONST XENSTORE_TRANSACTION
*Transaction
,
1263 IN CONST CHAR8
*DirectoryPath
,
1264 IN CONST CHAR8
*Node
1268 XENSTORE_STATUS Status
;
1270 Path
= XenStoreJoin (DirectoryPath
, Node
);
1271 Status
= XenStoreSingle (Transaction
, XS_RM
, Path
, NULL
, NULL
);
1278 XenStoreTransactionStart (
1279 OUT XENSTORE_TRANSACTION
*Transaction
1283 XENSTORE_STATUS Status
;
1285 Status
= XenStoreSingle (XST_NIL
, XS_TRANSACTION_START
, "", NULL
,
1287 if (Status
== XENSTORE_STATUS_SUCCESS
) {
1288 Transaction
->Id
= (UINT32
)AsciiStrDecimalToUintn (IdStr
);
1296 XenStoreTransactionEnd (
1297 IN CONST XENSTORE_TRANSACTION
*Transaction
,
1303 AbortStr
[0] = Abort
? 'F' : 'T';
1306 return XenStoreSingle (Transaction
, XS_TRANSACTION_END
, AbortStr
, NULL
, NULL
);
1311 IN CONST XENSTORE_TRANSACTION
*Transaction
,
1312 IN CONST CHAR8
*DirectoryPath
,
1313 IN CONST CHAR8
*Node
,
1314 IN CONST CHAR8
*FormatString
,
1319 XENSTORE_STATUS Status
;
1323 VA_COPY (Marker2
, Marker
);
1324 BufSize
= SPrintLengthAsciiFormat (FormatString
, Marker2
) + 1;
1326 Buf
= AllocateZeroPool (BufSize
);
1327 AsciiVSPrint (Buf
, BufSize
, FormatString
, Marker
);
1328 Status
= XenStoreWrite (Transaction
, DirectoryPath
, Node
, Buf
);
1337 IN CONST XENSTORE_TRANSACTION
*Transaction
,
1338 IN CONST CHAR8
*DirectoryPath
,
1339 IN CONST CHAR8
*Node
,
1340 IN CONST CHAR8
*FormatString
,
1345 XENSTORE_STATUS Status
;
1347 VA_START (Marker
, FormatString
);
1348 Status
= XenStoreVSPrint (Transaction
, DirectoryPath
, Node
, FormatString
, Marker
);
1355 XenStoreRegisterWatch (
1356 IN CONST CHAR8
*DirectoryPath
,
1357 IN CONST CHAR8
*Node
,
1358 OUT XENSTORE_WATCH
**WatchPtr
1361 /* Pointer in ascii is the token. */
1362 CHAR8 Token
[sizeof (XENSTORE_WATCH
) * 2 + 1];
1363 XENSTORE_STATUS Status
;
1364 XENSTORE_WATCH
*Watch
;
1366 Watch
= AllocateZeroPool (sizeof (XENSTORE_WATCH
));
1367 Watch
->Signature
= XENSTORE_WATCH_SIGNATURE
;
1368 Watch
->Node
= XenStoreJoin (DirectoryPath
, Node
);
1370 EfiAcquireLock (&xs
.RegisteredWatchesLock
);
1371 InsertTailList (&xs
.RegisteredWatches
, &Watch
->Link
);
1372 EfiReleaseLock (&xs
.RegisteredWatchesLock
);
1374 AsciiSPrint (Token
, sizeof (Token
), "%p", (VOID
*) Watch
);
1375 Status
= XenStoreWatch (Watch
->Node
, Token
);
1377 /* Ignore errors due to multiple registration. */
1378 if (Status
== XENSTORE_STATUS_EEXIST
) {
1379 Status
= XENSTORE_STATUS_SUCCESS
;
1382 if (Status
== XENSTORE_STATUS_SUCCESS
) {
1385 EfiAcquireLock (&xs
.RegisteredWatchesLock
);
1386 RemoveEntryList (&Watch
->Link
);
1387 EfiReleaseLock (&xs
.RegisteredWatchesLock
);
1388 FreePool (Watch
->Node
);
1396 XenStoreUnregisterWatch (
1397 IN XENSTORE_WATCH
*Watch
1400 CHAR8 Token
[sizeof (Watch
) * 2 + 1];
1403 ASSERT (Watch
->Signature
== XENSTORE_WATCH_SIGNATURE
);
1405 AsciiSPrint (Token
, sizeof (Token
), "%p", (VOID
*) Watch
);
1406 if (XenStoreFindWatch (Token
) == NULL
) {
1410 EfiAcquireLock (&xs
.RegisteredWatchesLock
);
1411 RemoveEntryList (&Watch
->Link
);
1412 EfiReleaseLock (&xs
.RegisteredWatchesLock
);
1414 XenStoreUnwatch (Watch
->Node
, Token
);
1416 /* Cancel pending watch events. */
1417 EfiAcquireLock (&xs
.WatchEventsLock
);
1418 Entry
= GetFirstNode (&xs
.WatchEvents
);
1419 while (!IsNull (&xs
.WatchEvents
, Entry
)) {
1420 XENSTORE_MESSAGE
*Message
= XENSTORE_MESSAGE_FROM_LINK (Entry
);
1421 Entry
= GetNextNode (&xs
.WatchEvents
, Entry
);
1422 if (Message
->u
.Watch
.Handle
== Watch
) {
1423 RemoveEntryList (&Message
->Link
);
1424 FreePool ((VOID
*)Message
->u
.Watch
.Vector
);
1428 EfiReleaseLock (&xs
.WatchEventsLock
);
1430 FreePool (Watch
->Node
);
1441 XenBusWaitForWatch (
1442 IN XENBUS_PROTOCOL
*This
,
1446 return XenStoreWaitWatch (Token
);
1451 XenBusXenStoreRead (
1452 IN XENBUS_PROTOCOL
*This
,
1453 IN CONST XENSTORE_TRANSACTION
*Transaction
,
1454 IN CONST CHAR8
*Node
,
1458 return XenStoreRead (Transaction
, This
->Node
, Node
, NULL
, Value
);
1463 XenBusXenStoreBackendRead (
1464 IN XENBUS_PROTOCOL
*This
,
1465 IN CONST XENSTORE_TRANSACTION
*Transaction
,
1466 IN CONST CHAR8
*Node
,
1470 return XenStoreRead (Transaction
, This
->Backend
, Node
, NULL
, Value
);
1475 XenBusXenStoreRemove (
1476 IN XENBUS_PROTOCOL
*This
,
1477 IN CONST XENSTORE_TRANSACTION
*Transaction
,
1481 return XenStoreRemove (Transaction
, This
->Node
, Node
);
1486 XenBusXenStoreTransactionStart (
1487 IN XENBUS_PROTOCOL
*This
,
1488 OUT XENSTORE_TRANSACTION
*Transaction
1491 return XenStoreTransactionStart (Transaction
);
1496 XenBusXenStoreTransactionEnd (
1497 IN XENBUS_PROTOCOL
*This
,
1498 IN CONST XENSTORE_TRANSACTION
*Transaction
,
1502 return XenStoreTransactionEnd (Transaction
, Abort
);
1507 XenBusXenStoreSPrint (
1508 IN XENBUS_PROTOCOL
*This
,
1509 IN CONST XENSTORE_TRANSACTION
*Transaction
,
1510 IN CONST CHAR8
*DirectoryPath
,
1511 IN CONST CHAR8
*Node
,
1512 IN CONST CHAR8
*FormatString
,
1517 XENSTORE_STATUS Status
;
1519 VA_START (Marker
, FormatString
);
1520 Status
= XenStoreVSPrint (Transaction
, DirectoryPath
, Node
, FormatString
, Marker
);
1528 XenBusRegisterWatch (
1529 IN XENBUS_PROTOCOL
*This
,
1530 IN CONST CHAR8
*Node
,
1534 return XenStoreRegisterWatch (This
->Node
, Node
, (XENSTORE_WATCH
**) Token
);
1539 XenBusRegisterWatchBackend (
1540 IN XENBUS_PROTOCOL
*This
,
1541 IN CONST CHAR8
*Node
,
1545 return XenStoreRegisterWatch (This
->Backend
, Node
, (XENSTORE_WATCH
**) Token
);
1550 XenBusUnregisterWatch (
1551 IN XENBUS_PROTOCOL
*This
,
1555 XenStoreUnregisterWatch ((XENSTORE_WATCH
*) Token
);