OvmfPkg/XenBusDxe: Add XenStore client implementation

XenStore is a key/value database, which is running on another virtual
machine. It can be accessed through shared memory. This is a client
implementation.

Change in V3:
- moving xs_wire.h from patch #1 to this patch
- fix return value of XenStoreListDirectory
- Use a timeout to print a debug message if the other side of the
  xenstore ring does not notify through the event channel.
  This is done with the new XenStoreWaitForEvent function.
- Have XenStoreReadReply check status of XenStoreProcessMessage and
  return an error if needed.
- Have XenStoreTalkv return the status of XenStoreReadReply.
- Have a loop to check for the quiescent of the response ring in the
  XenStoreInitComms function. (with a timeout of 5 seconds)
- use the recently introduced XenStore 'closing' feature.

Change in V2:
- Change comment style, from freebsd to ovmf
- Fix type of EventChannel
- Fix debug print, no more cast
- Implement XenStoreDeinit.
- Clean up comments
- Fix few codding style issue
- Add FAIL xenstore status value.

Origin: FreeBSD 10.0
License: This patch adds several files under the MIT licence.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16267 6f19259b-4bc3-4df7-8a09-765794883524

OvmfPkg/Include/IndustryStandard/Xen/io/xs_wire.h

@@ -0,0 +1,149 @@
+/*
+ * Details of the "wire" protocol between Xen Store Daemon and client
+ * library or guest kernel.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Copyright (C) 2005 Rusty Russell IBM Corporation
+ */
+
+#ifndef _XS_WIRE_H
+#define _XS_WIRE_H
+
+enum xsd_sockmsg_type
+{
+    XS_DEBUG,
+    XS_DIRECTORY,
+    XS_READ,
+    XS_GET_PERMS,
+    XS_WATCH,
+    XS_UNWATCH,
+    XS_TRANSACTION_START,
+    XS_TRANSACTION_END,
+    XS_INTRODUCE,
+    XS_RELEASE,
+    XS_GET_DOMAIN_PATH,
+    XS_WRITE,
+    XS_MKDIR,
+    XS_RM,
+    XS_SET_PERMS,
+    XS_WATCH_EVENT,
+    XS_ERROR,
+    XS_IS_DOMAIN_INTRODUCED,
+    XS_RESUME,
+    XS_SET_TARGET,
+    XS_RESTRICT,
+    XS_RESET_WATCHES,
+
+    XS_INVALID = 0xffff /* Guaranteed to remain an invalid type */
+};
+
+#define XS_WRITE_NONE "NONE"
+#define XS_WRITE_CREATE "CREATE"
+#define XS_WRITE_CREATE_EXCL "CREATE|EXCL"
+
+/* We hand errors as strings, for portability. */
+struct xsd_errors
+{
+    INT32 errnum;
+    const CHAR8 *errstring;
+};
+#ifdef EINVAL
+#define XSD_ERROR(x) { x, #x }
+/* LINTED: static unused */
+static struct xsd_errors xsd_errors[]
+#if defined(__GNUC__)
+__attribute__((unused))
+#endif
+    = {
+    XSD_ERROR(EINVAL),
+    XSD_ERROR(EACCES),
+    XSD_ERROR(EEXIST),
+    XSD_ERROR(EISDIR),
+    XSD_ERROR(ENOENT),
+    XSD_ERROR(ENOMEM),
+    XSD_ERROR(ENOSPC),
+    XSD_ERROR(EIO),
+    XSD_ERROR(ENOTEMPTY),
+    XSD_ERROR(ENOSYS),
+    XSD_ERROR(EROFS),
+    XSD_ERROR(EBUSY),
+    XSD_ERROR(EAGAIN),
+    XSD_ERROR(EISCONN),
+    XSD_ERROR(E2BIG)
+};
+#endif
+
+struct xsd_sockmsg
+{
+    UINT32 type;  /* XS_??? */
+    UINT32 req_id;/* Request identifier, echoed in daemon's response.  */
+    UINT32 tx_id; /* Transaction id (0 if not related to a transaction). */
+    UINT32 len;   /* Length of data following this. */
+
+    /* Generally followed by nul-terminated string(s). */
+};
+
+enum xs_watch_type
+{
+    XS_WATCH_PATH = 0,
+    XS_WATCH_TOKEN
+};
+
+/*
+ * `incontents 150 xenstore_struct XenStore wire protocol.
+ *
+ * Inter-domain shared memory communications. */
+#define XENSTORE_RING_SIZE 1024
+typedef UINT32 XENSTORE_RING_IDX;
+#define MASK_XENSTORE_IDX(idx) ((idx) & (XENSTORE_RING_SIZE-1))
+struct xenstore_domain_interface {
+    CHAR8 req[XENSTORE_RING_SIZE]; /* Requests to xenstore daemon. */
+    CHAR8 rsp[XENSTORE_RING_SIZE]; /* Replies and async watch events. */
+    XENSTORE_RING_IDX req_cons, req_prod;
+    XENSTORE_RING_IDX rsp_cons, rsp_prod;
+    UINT32 server_features; /* Bitmap of features supported by the server */
+    UINT32 connection;
+};
+
+/* Violating this is very bad.  See docs/misc/xenstore.txt. */
+#define XENSTORE_PAYLOAD_MAX 4096
+
+/* Violating these just gets you an error back */
+#define XENSTORE_ABS_PATH_MAX 3072
+#define XENSTORE_REL_PATH_MAX 2048
+
+/* The ability to reconnect a ring */
+#define XENSTORE_SERVER_FEATURE_RECONNECTION 1
+
+/* Valid values for the connection field */
+#define XENSTORE_CONNECTED 0 /* the steady-state */
+#define XENSTORE_RECONNECT 1 /* guest has initiated a reconnect */
+
+#endif /* _XS_WIRE_H */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */

OvmfPkg/Include/Protocol/XenBus.h

@@ -32,6 +32,35 @@
 ///
 typedef struct _XENBUS_PROTOCOL XENBUS_PROTOCOL;
 
+typedef enum xenbus_state XenBusState;
+
+typedef struct
+{
+  UINT32 Id;
+} XENSTORE_TRANSACTION;
+
+#define XST_NIL ((XENSTORE_TRANSACTION) { 0 })
+
+typedef enum {
+  XENSTORE_STATUS_SUCCESS = 0,
+  XENSTORE_STATUS_FAIL,
+  XENSTORE_STATUS_EINVAL,
+  XENSTORE_STATUS_EACCES,
+  XENSTORE_STATUS_EEXIST,
+  XENSTORE_STATUS_EISDIR,
+  XENSTORE_STATUS_ENOENT,
+  XENSTORE_STATUS_ENOMEM,
+  XENSTORE_STATUS_ENOSPC,
+  XENSTORE_STATUS_EIO,
+  XENSTORE_STATUS_ENOTEMPTY,
+  XENSTORE_STATUS_ENOSYS,
+  XENSTORE_STATUS_EROFS,
+  XENSTORE_STATUS_EBUSY,
+  XENSTORE_STATUS_EAGAIN,
+  XENSTORE_STATUS_EISCONN,
+  XENSTORE_STATUS_E2BIG
+} XENSTORE_STATUS;
+
 
 #include <IndustryStandard/Xen/grant_table.h>
 

OvmfPkg/XenBusDxe/XenBusDxe.c

@@ -31,6 +31,7 @@
 
 #include "XenHypercall.h"
 #include "GrantTable.h"
+#include "XenStore.h"
 
 
 ///
@@ -346,6 +347,9 @@ XenBusDxeDriverBindingStart (
 
   XenGrantTableInit (Dev, MmioAddr);
 
+  Status = XenStoreInit (Dev);
+  ASSERT_EFI_ERROR (Status);
+
   Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,
                              NotifyExitBoot,
                              (VOID*) Dev,
@@ -399,6 +403,7 @@ XenBusDxeDriverBindingStop (
   XENBUS_DEVICE *Dev = mMyDevice;
 
   gBS->CloseEvent (Dev->ExitBootEvent);
+  XenStoreDeinit (Dev);
   XenGrantTableDeinit (Dev);
 
   gBS->CloseProtocol (ControllerHandle, &gEfiPciIoProtocolGuid,

OvmfPkg/XenBusDxe/XenBusDxe.inf

@@ -42,6 +42,8 @@
   GrantTable.h
   EventChannel.c
   EventChannel.h
+  XenStore.c
+  XenStore.h
 
 [Sources.IA32]
   Ia32/hypercall.S

OvmfPkg/XenBusDxe/XenStore.h

@@ -0,0 +1,292 @@
+/** @file
+  Method declarations and structures for accessing the XenStore
+
+  Copyright (C) 2005 Rusty Russell, IBM Corporation
+  Copyright (C) 2005 XenSource Ltd.
+  Copyright (C) 2009,2010 Spectra Logic Corporation
+  Copyright (C) 2014, Citrix Ltd.
+
+  This file may be distributed separately from the Linux kernel, or
+  incorporated into other software packages, subject to the following license:
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this source file (the "Software"), to deal in the Software without
+  restriction, including without limitation the rights to use, copy, modify,
+  merge, publish, distribute, sublicense, and/or sell copies of the Software,
+  and to permit persons to whom the Software is furnished to do so, subject to
+  the following conditions:
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+  IN THE SOFTWARE.
+**/
+
+#ifndef _XEN_XENSTORE_XENSTOREVAR_H
+#define _XEN_XENSTORE_XENSTOREVAR_H
+
+#include "XenBusDxe.h"
+
+#include <IndustryStandard/Xen/io/xs_wire.h>
+
+typedef struct _XENSTORE_WATCH XENSTORE_WATCH;
+
+/**
+  Fetch the contents of a directory in the XenStore.
+
+  @param Transaction        The XenStore transaction covering this request.
+  @param DirectoryPath      The dirname of the path to read.
+  @param Node               The basename of the path to read.
+  @param DirectoryCountPtr  The returned number of directory entries.
+  @param DirectoryListPtr   An array of directory entry strings.
+
+  @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
+           indicating the type of failure.
+
+  @note The results buffer is alloced and should be free'd by the
+        caller.
+**/
+XENSTORE_STATUS
+XenStoreListDirectory (
+  IN  XENSTORE_TRANSACTION  Transaction,
+  IN  CONST CHAR8           *DirectoryPath,
+  IN  CONST CHAR8           *Node,
+  OUT UINT32                *DirectoryCountPtr,
+  OUT CONST CHAR8           ***DirectoryListPtr
+  );
+
+/**
+  Determine if a path exists in the XenStore.
+
+  @param Transaction  The XenStore transaction covering this request.
+  @param Directory    The dirname of the path to read.
+  @param Node         The basename of the path to read.
+
+  @retval TRUE  The path exists.
+  @retval FALSE The path does not exist or an error occurred attempting
+                to make that determination.
+**/
+BOOLEAN
+XenStorePathExists (
+  IN XENSTORE_TRANSACTION  Transaction,
+  IN CONST CHAR8 *Directory,
+  IN CONST CHAR8 *Node
+  );
+
+/**
+  Get the contents of a single "file".  Returns the contents in *Result which
+  should be freed after use.  The length of the value in bytes is returned in
+  *LenPtr.
+
+  @param Transaction    The XenStore transaction covering this request.
+  @param DirectoryPath  The dirname of the file to read.
+  @param Node           The basename of the file to read.
+  @param LenPtr         The amount of data read.
+  @param Result         The returned contents from this file.
+
+  @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
+           indicating the type of failure.
+
+  @note The results buffer is malloced and should be free'd by the
+        caller.
+**/
+XENSTORE_STATUS
+XenStoreRead (
+  IN  XENSTORE_TRANSACTION    Transaction,
+  IN  CONST CHAR8             *DirectoryPath,
+  IN  CONST CHAR8             *Node,
+  OUT UINT32                  *LenPtr OPTIONAL,
+  OUT VOID                    **Result
+  );
+
+/**
+  Write to a single file.
+
+  @param Transaction    The XenStore transaction covering this request.
+  @param DirectoryPath  The dirname of the file to write.
+  @param Node           The basename of the file to write.
+  @param Str            The NUL terminated string of data to write.
+
+  @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
+           indicating the type of failure.
+**/
+XENSTORE_STATUS
+XenStoreWrite (
+  IN XENSTORE_TRANSACTION  Transaction,
+  IN CONST CHAR8           *DirectoryPath,
+  IN CONST CHAR8           *Node,
+  IN CONST CHAR8           *Str
+  );
+
+/**
+  Remove a file or directory (directories must be empty).
+
+  @param Transaction    The XenStore transaction covering this request.
+  @param DirectoryPath  The dirname of the directory to remove.
+  @param Node           The basename of the directory to remove.
+
+  @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
+           indicating the type of failure.
+**/
+XENSTORE_STATUS
+XenStoreRemove (
+  IN XENSTORE_TRANSACTION   Transaction,
+  IN CONST CHAR8            *DirectoryPath,
+  IN CONST CHAR8            *Node
+  );
+
+/**
+  Start a transaction.
+
+  Changes by others will not be seen during the lifetime of this
+  transaction, and changes will not be visible to others until it
+  is committed (XenStoreTransactionEnd).
+
+  @param Transaction  The returned transaction.
+
+  @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
+           indicating the type of failure.
+**/
+XENSTORE_STATUS
+XenStoreTransactionStart (
+  OUT XENSTORE_TRANSACTION  *Transaction
+  );
+
+/**
+  End a transaction.
+
+  @param Transaction  The transaction to end/commit.
+  @param Abort        If TRUE, the transaction is discarded
+                      instead of committed.
+
+  @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
+           indicating the type of failure.
+**/
+XENSTORE_STATUS
+XenStoreTransactionEnd (
+  IN XENSTORE_TRANSACTION   Transaction,
+  IN BOOLEAN                Abort
+  );
+
+/**
+  Printf formatted write to a XenStore file.
+
+  @param Transaction      The XenStore transaction covering this request.
+  @param DirectoryPath    The dirname of the path to read.
+  @param Node             The basename of the path to read.
+  @param FormatString     AsciiSPrint format string followed by a variable number
+                          of arguments.
+
+  @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
+           indicating the type of write failure.
+**/
+XENSTORE_STATUS
+EFIAPI
+XenStoreSPrint (
+  IN XENSTORE_TRANSACTION   Transaction,
+  IN CONST CHAR8            *DirectoryPath,
+  IN CONST CHAR8            *Node,
+  IN CONST CHAR8            *FormatString,
+  ...
+  );
+
+/**
+  VA_LIST version of XenStoreSPrint().
+
+  @param Transaction    The XenStore transaction covering this request.
+  @param DirectoryPath  The dirname of the path to read.
+  @param Node           The basename of the path to read.
+  @param FormatString   Printf format string.
+  @param Marker         VA_LIST of printf arguments.
+
+  @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
+           indicating the type of write failure.
+**/
+XENSTORE_STATUS
+XenStoreVSPrint (
+  IN XENSTORE_TRANSACTION  Transaction,
+  IN CONST CHAR8           *DirectoryPath,
+  IN CONST CHAR8           *Node,
+  IN CONST CHAR8           *FormatString,
+  IN VA_LIST               Marker
+  );
+
+/**
+  Register a XenStore watch.
+
+  XenStore watches allow a client to be notified via a callback (embedded
+  within the watch object) of changes to an object in the XenStore.
+
+  @param DirectoryPath  The dirname of the path to watch.
+  @param Node           The basename of the path to watch.
+  @param WatchPtr       A returned XENSTORE_WATCH pointer.
+
+  @return  On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
+           indicating the type of write failure.  EEXIST errors from the
+           XenStore are supressed, allowing multiple, physically different,
+           xenbus_watch objects, to watch the same path in the XenStore.
+**/
+XENSTORE_STATUS
+XenStoreRegisterWatch (
+  IN  CONST CHAR8     *DirectoryPath,
+  IN  CONST CHAR8     *Node,
+  OUT XENSTORE_WATCH  **WatchPtr
+  );
+
+/**
+  Unregister a XenStore watch.
+
+  @param Watch  An XENSTORE_WATCH object previously returned by a successful
+                call to XenStoreRegisterWatch ().
+**/
+VOID
+XenStoreUnregisterWatch (
+  IN XENSTORE_WATCH *Watch
+  );
+
+/**
+  Allocate and return the XenStore path string <DirectoryPath>/<Node>.  If name
+  is the NUL string, the returned value contains the path string
+  <DirectoryPath>.
+
+  @param DirectoryPath	The NUL terminated directory prefix for new path.
+  @param Node           The NUL terminated basename for the new path.
+
+  @return  A buffer containing the joined path.
+ */
+CHAR8 *
+XenStoreJoin (
+  IN CONST CHAR8 *DirectoryPath,
+  IN CONST CHAR8 *Node
+  );
+
+
+/**
+  Initialize the XenStore states and rings.
+
+  @param Dev  A pointer to a XENBUS_DEVICE instance.
+
+  @return     EFI_SUCCESS if everything went smoothly.
+**/
+EFI_STATUS
+XenStoreInit (
+  XENBUS_DEVICE *Dev
+  );
+
+/**
+  Deinitialize the XenStore states and rings.
+
+  @param Dev  A pointer to a XENBUS_DEVICE instance.
+**/
+VOID
+XenStoreDeinit (
+  IN XENBUS_DEVICE *Dev
+  );
+
+#endif /* _XEN_XENSTORE_XENSTOREVAR_H */