1 
2 /** @file
3   XenBus protocol to be used between the XenBus bus driver and Xen PV devices.
4 
5   DISCLAIMER: the XENBUS_PROTOCOL introduced here is a work in progress, and
6   should not be used outside of the EDK II tree.
7 
8   This protocol provide the necessary for a Xen PV driver frontend to
9   communicate with the bus driver, and perform several task to
10   initialize/shutdown a PV device and perform IO with a PV backend.
11 
12   Copyright (C) 2014, Citrix Ltd.
13 
14   This program and the accompanying materials
15   are licensed and made available under the terms and conditions of the BSD License
16   which accompanies this distribution.  The full text of the license may be found at
17   http://opensource.org/licenses/bsd-license.php
18 
19   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
20   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
21 
22 **/
23 
24 #ifndef __PROTOCOL_XENBUS_H__
25 #define __PROTOCOL_XENBUS_H__
26 
27 #define XENBUS_PROTOCOL_GUID \
28   {0x3d3ca290, 0xb9a5, 0x11e3, {0xb7, 0x5d, 0xb8, 0xac, 0x6f, 0x7d, 0x65, 0xe6}}
29 
30 ///
31 /// Forward declaration
32 ///
33 typedef struct _XENBUS_PROTOCOL XENBUS_PROTOCOL;
34 
35 typedef enum xenbus_state XenBusState;
36 
37 typedef struct
38 {
39   UINT32 Id;
40 } XENSTORE_TRANSACTION;
41 
42 #define XST_NIL ((XENSTORE_TRANSACTION *) NULL)
43 
44 typedef enum {
45   XENSTORE_STATUS_SUCCESS = 0,
46   XENSTORE_STATUS_FAIL,
47   XENSTORE_STATUS_EINVAL,
48   XENSTORE_STATUS_EACCES,
49   XENSTORE_STATUS_EEXIST,
50   XENSTORE_STATUS_EISDIR,
51   XENSTORE_STATUS_ENOENT,
52   XENSTORE_STATUS_ENOMEM,
53   XENSTORE_STATUS_ENOSPC,
54   XENSTORE_STATUS_EIO,
55   XENSTORE_STATUS_ENOTEMPTY,
56   XENSTORE_STATUS_ENOSYS,
57   XENSTORE_STATUS_EROFS,
58   XENSTORE_STATUS_EBUSY,
59   XENSTORE_STATUS_EAGAIN,
60   XENSTORE_STATUS_EISCONN,
61   XENSTORE_STATUS_E2BIG
62 } XENSTORE_STATUS;
63 
64 
65 #include <IndustryStandard/Xen/grant_table.h>
66 #include <IndustryStandard/Xen/event_channel.h>
67 
68 ///
69 /// Function prototypes
70 ///
71 
72 /**
73   Get the contents of the node Node of the PV device. Returns the contents in
74   *Result which should be freed after use.
75 
76   @param This           A pointer to XENBUS_PROTOCOL instance.
77   @param Transaction    The XenStore transaction covering this request.
78   @param Node           The basename of the file to read.
79   @param Result         The returned contents from this file.
80 
81   @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
82            indicating the type of failure.
83 
84   @note The results buffer is malloced and should be free'd by the
85         caller.
86 **/
87 typedef
88 XENSTORE_STATUS
89 (EFIAPI *XENBUS_XS_READ)(
90   IN  XENBUS_PROTOCOL       *This,
91   IN  CONST XENSTORE_TRANSACTION *Transaction,
92   IN  CONST CHAR8           *Node,
93   OUT VOID                  **Result
94   );
95 
96 /**
97   Get the contents of the node Node of the PV device's backend. Returns the
98   contents in *Result which should be freed after use.
99 
100   @param This           A pointer to XENBUS_PROTOCOL instance.
101   @param Transaction    The XenStore transaction covering this request.
102   @param Node           The basename of the file to read.
103   @param Result         The returned contents from this file.
104 
105   @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
106            indicating the type of failure.
107 
108   @note The results buffer is malloced and should be free'd by the
109         caller.
110 **/
111 typedef
112 XENSTORE_STATUS
113 (EFIAPI *XENBUS_XS_BACKEND_READ)(
114   IN  XENBUS_PROTOCOL       *This,
115   IN  CONST XENSTORE_TRANSACTION *Transaction,
116   IN  CONST CHAR8           *Node,
117   OUT VOID                  **Result
118   );
119 
120 /**
121   Print formatted write to a XenStore node.
122 
123   @param This             A pointer to XENBUS_PROTOCOL instance.
124   @param Transaction      The XenStore transaction covering this request.
125   @param Directory        The dirname of the path to read.
126   @param Node             The basename of the path to read.
127   @param Format           AsciiSPrint format string followed by a variable number
128                           of arguments.
129 
130   @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
131            indicating the type of write failure.
132 **/
133 typedef
134 XENSTORE_STATUS
135 (EFIAPI *XENBUS_XS_PRINTF) (
136   IN XENBUS_PROTOCOL        *This,
137   IN CONST XENSTORE_TRANSACTION *Transaction,
138   IN CONST CHAR8            *Directory,
139   IN CONST CHAR8            *Node,
140   IN CONST CHAR8            *Format,
141   ...
142   );
143 
144 /**
145   Remove a node or directory (directories must be empty) of the PV driver's
146   subdirectory.
147 
148   @param This           A pointer to XENBUS_PROTOCOL instance.
149   @param Transaction    The XenStore transaction covering this request.
150   @param Node           The basename of the node to remove.
151 
152   @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
153            indicating the type of failure.
154 **/
155 typedef
156 XENSTORE_STATUS
157 (EFIAPI *XENBUS_XS_REMOVE) (
158   IN XENBUS_PROTOCOL        *This,
159   IN CONST XENSTORE_TRANSACTION *Transaction,
160   IN CONST CHAR8            *Node
161   );
162 
163 /**
164   Start a transaction.
165 
166   Changes by others will not be seen during the lifetime of this
167   transaction, and changes will not be visible to others until it
168   is committed (XsTransactionEnd).
169 
170   @param This         A pointer to XENBUS_PROTOCOL instance.
171   @param Transaction  The returned transaction.
172 
173   @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
174            indicating the type of failure.
175 **/
176 typedef
177 XENSTORE_STATUS
178 (EFIAPI *XENBUS_XS_TRANSACTION_START)(
179   IN  XENBUS_PROTOCOL       *This,
180   OUT XENSTORE_TRANSACTION  *Transaction
181   );
182 
183 /**
184   End a transaction.
185 
186   @param This         A pointer to XENBUS_PROTOCOL instance.
187   @param Transaction  The transaction to end/commit.
188   @param Abort        If TRUE, the transaction is discarded
189                       instead of committed.
190 
191   @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
192            indicating the type of failure.
193 **/
194 typedef
195 XENSTORE_STATUS
196 (EFIAPI *XENBUS_XS_TRANSACTION_END) (
197   IN XENBUS_PROTOCOL        *This,
198   IN CONST XENSTORE_TRANSACTION *Transaction,
199   IN BOOLEAN                Abort
200   );
201 
202 /**
203   Set a new state for the frontend of the PV driver.
204 
205   @param This         A pointer to XENBUS_PROTOCOL instance.
206   @param Transaction  The transaction to end/commit.
207   @param State        The new state to apply.
208 
209   @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
210            indicating the type of failure.
211 **/
212 typedef
213 XENSTORE_STATUS
214 (EFIAPI *XENBUS_SET_STATE)(
215   IN XENBUS_PROTOCOL        *This,
216   IN CONST XENSTORE_TRANSACTION *Transaction,
217   IN XenBusState            State
218   );
219 
220 /**
221   Grant access to the page Frame to the domain DomainId.
222 
223   @param This       A pointer to XENBUS_PROTOCOL instance.
224   @param DomainId   ID of the domain to grant acces to.
225   @param Frame      Frame Number of the page to grant access to.
226   @param ReadOnly   Provide read-only or read-write access.
227   @param RefPtr     Reference number of the grant will be writen to this pointer.
228 **/
229 typedef
230 EFI_STATUS
231 (EFIAPI *XENBUS_GRANT_ACCESS)(
232   IN  XENBUS_PROTOCOL *This,
233   IN  domid_t         DomainId,
234   IN  UINTN           Frame,
235   IN  BOOLEAN         ReadOnly,
236   OUT grant_ref_t     *refp
237   );
238 
239 /**
240   End access to grant Ref, previously return by XenBusGrantAccess.
241 
242   @param This       A pointer to XENBUS_PROTOCOL instance.
243   @param Ref        Reference numeber of a grant previously returned by
244                     XenBusGrantAccess.
245 **/
246 typedef
247 EFI_STATUS
248 (EFIAPI *XENBUS_GRANT_END_ACCESS)(
249   IN XENBUS_PROTOCOL  *This,
250   IN grant_ref_t      Ref
251   );
252 
253 /**
254   Allocate a port that can be bind from domain DomainId.
255 
256   @param This       A pointer to the XENBUS_PROTOCOL.
257   @param DomainId   The domain ID that can bind the newly allocated port.
258   @param Port       A pointer to a evtchn_port_t that will contain the newly
259                     allocated port.
260 
261   @retval UINT32    The return value from the hypercall, 0 if success.
262 **/
263 typedef
264 UINT32
265 (EFIAPI *XENBUS_EVENT_CHANNEL_ALLOCATE) (
266   IN  XENBUS_PROTOCOL *This,
267   IN  domid_t         DomainId,
268   OUT evtchn_port_t   *Port
269   );
270 
271 /**
272   Send an event to the remote end of the channel whose local endpoint is Port.
273 
274   @param This       A pointer to the XENBUS_PROTOCOL.
275   @param Port       Local port to the the event from.
276 
277   @retval UINT32    The return value from the hypercall, 0 if success.
278 **/
279 typedef
280 UINT32
281 (EFIAPI *XENBUS_EVENT_CHANNEL_NOTIFY) (
282   IN XENBUS_PROTOCOL  *This,
283   IN evtchn_port_t    Port
284   );
285 
286 /**
287   Close a local event channel Port.
288 
289   @param This       A pointer to the XENBUS_PROTOCOL.
290   @param Port       The event channel to close.
291 
292   @retval UINT32    The return value from the hypercall, 0 if success.
293 **/
294 typedef
295 UINT32
296 (EFIAPI *XENBUS_EVENT_CHANNEL_CLOSE) (
297   IN XENBUS_PROTOCOL  *This,
298   IN evtchn_port_t    Port
299   );
300 
301 /**
302   Register a XenStore watch.
303 
304   XenStore watches allow a client to wait for changes to an object in the
305   XenStore.
306 
307   @param This       A pointer to the XENBUS_PROTOCOL.
308   @param Node       The basename of the path to watch.
309   @param Token      A token.
310 
311   @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
312            indicating the type of write failure.  EEXIST errors from the
313            XenStore are supressed, allowing multiple, physically different,
314            xenbus_watch objects, to watch the same path in the XenStore.
315 **/
316 typedef
317 XENSTORE_STATUS
318 (EFIAPI *XENBUS_REGISTER_WATCH) (
319   IN  XENBUS_PROTOCOL *This,
320   IN  CONST CHAR8     *Node,
321   OUT VOID            **Token
322   );
323 
324 /**
325   Register a XenStore watch on a backend's node.
326 
327   XenStore watches allow a client to wait for changes to an object in the
328   XenStore.
329 
330   @param This       A pointer to the XENBUS_PROTOCOL.
331   @param Node       The basename of the path to watch.
332   @param Token      A token.
333 
334   @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
335            indicating the type of write failure.  EEXIST errors from the
336            XenStore are supressed, allowing multiple, physically different,
337            xenbus_watch objects, to watch the same path in the XenStore.
338 **/
339 typedef
340 XENSTORE_STATUS
341 (EFIAPI *XENBUS_REGISTER_WATCH_BACKEND) (
342   IN  XENBUS_PROTOCOL *This,
343   IN  CONST CHAR8     *Node,
344   OUT VOID            **Token
345   );
346 
347 /**
348   Unregister a XenStore watch.
349 
350   @param This   A pointer to the XENBUS_PROTOCOL.
351   @param Token  An token previously returned by a successful
352                 call to RegisterWatch ().
353 **/
354 typedef
355 VOID
356 (EFIAPI *XENBUS_UNREGISTER_WATCH) (
357   IN XENBUS_PROTOCOL  *This,
358   IN VOID             *Token
359   );
360 
361 /**
362   Block until the node watch by Token change.
363 
364   @param This   A pointer to the XENBUS_PROTOCOL.
365   @param Token  An token previously returned by a successful
366                 call to RegisterWatch or RegisterWatchBackend.
367 
368   @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
369            indicating the type of failure.
370 **/
371 typedef
372 XENSTORE_STATUS
373 (EFIAPI *XENBUS_WAIT_FOR_WATCH) (
374   IN XENBUS_PROTOCOL  *This,
375   IN VOID             *Token
376   );
377 
378 
379 ///
380 /// Protocol structure
381 ///
382 /// DISCLAIMER: the XENBUS_PROTOCOL introduced here is a work in progress, and
383 /// should not be used outside of the EDK II tree.
384 ///
385 struct _XENBUS_PROTOCOL {
386   XENBUS_XS_READ                XsRead;
387   XENBUS_XS_BACKEND_READ        XsBackendRead;
388   XENBUS_XS_PRINTF              XsPrintf;
389   XENBUS_XS_REMOVE              XsRemove;
390   XENBUS_XS_TRANSACTION_START   XsTransactionStart;
391   XENBUS_XS_TRANSACTION_END     XsTransactionEnd;
392   XENBUS_SET_STATE              SetState;
393 
394   XENBUS_GRANT_ACCESS           GrantAccess;
395   XENBUS_GRANT_END_ACCESS       GrantEndAccess;
396 
397   XENBUS_EVENT_CHANNEL_ALLOCATE EventChannelAllocate;
398   XENBUS_EVENT_CHANNEL_NOTIFY   EventChannelNotify;
399   XENBUS_EVENT_CHANNEL_CLOSE    EventChannelClose;
400 
401   XENBUS_REGISTER_WATCH         RegisterWatch;
402   XENBUS_REGISTER_WATCH_BACKEND RegisterWatchBackend;
403   XENBUS_UNREGISTER_WATCH       UnregisterWatch;
404   XENBUS_WAIT_FOR_WATCH         WaitForWatch;
405   //
406   // Protocol data fields
407   //
408   CONST CHAR8                   *Type;
409   UINT16                        DeviceId;
410   CONST CHAR8                   *Node;
411   CONST CHAR8                   *Backend;
412 };
413 
414 extern EFI_GUID gXenBusProtocolGuid;
415 
416 #endif
417