OvmfPkg: Introduce XenBus Protocol.

This protocol will be used for communication between a PV driver (like a
PV block driver) and the XenBus/XenStore.

Change in V5:
- Replace the license by the commonly used file header text.

Change in V3:
- Add disclaimer about the volatile nature of the protocol.
- Add a description on the two introduced members to the protocol.

Change in V2:
- Comment, file header
- Protocol License
- Declare xen interface version earlier
- Rename protocol from Xenbus to XenBus

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16262 6f19259b-4bc3-4df7-8a09-765794883524

OvmfPkg/Include/Protocol/XenBus.h

@@ -0,0 +1,92 @@
+
+/** @file
+  XenBus protocol to be used between the XenBus bus driver and Xen PV devices.
+
+  DISCLAIMER: the XENBUS_PROTOCOL introduced here is a work in progress, and
+  should not be used outside of the EDK II tree.
+
+  This protocol provide the necessary for a Xen PV driver frontend to
+  communicate with the bus driver, and perform several task to
+  initialize/shutdown a PV device and perform IO with a PV backend.
+
+  Copyright (C) 2014, Citrix Ltd.
+
+  This program and the accompanying materials
+  are licensed and made available under the terms and conditions of the BSD License
+  which accompanies this distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#ifndef __PROTOCOL_XENBUS_H__
+#define __PROTOCOL_XENBUS_H__
+
+#define XENBUS_PROTOCOL_GUID \
+  {0x3d3ca290, 0xb9a5, 0x11e3, {0xb7, 0x5d, 0xb8, 0xac, 0x6f, 0x7d, 0x65, 0xe6}}
+
+///
+/// Forward declaration
+///
+typedef struct _XENBUS_PROTOCOL XENBUS_PROTOCOL;
+
+
+#include <IndustryStandard/Xen/grant_table.h>
+
+///
+/// Function prototypes
+///
+
+/**
+  Grant access to the page Frame to the domain DomainId.
+
+  @param This       A pointer to XENBUS_PROTOCOL instance.
+  @param DomainId   ID of the domain to grant acces to.
+  @param Frame      Frame Number of the page to grant access to.
+  @param ReadOnly   Provide read-only or read-write access.
+  @param RefPtr     Reference number of the grant will be writen to this pointer.
+**/
+typedef
+EFI_STATUS
+(EFIAPI *XENBUS_GRANT_ACCESS)(
+  IN  XENBUS_PROTOCOL *This,
+  IN  domid_t         DomainId,
+  IN  UINTN           Frame,
+  IN  BOOLEAN         ReadOnly,
+  OUT grant_ref_t     *refp
+  );
+
+/**
+  End access to grant Ref, previously return by XenBusGrantAccess.
+
+  @param This       A pointer to XENBUS_PROTOCOL instance.
+  @param Ref        Reference numeber of a grant previously returned by
+                    XenBusGrantAccess.
+**/
+typedef
+EFI_STATUS
+(EFIAPI *XENBUS_GRANT_END_ACCESS)(
+  IN XENBUS_PROTOCOL  *This,
+  IN grant_ref_t      Ref
+  );
+
+
+///
+/// Protocol structure
+///
+/// DISCLAIMER: the XENBUS_PROTOCOL introduced here is a work in progress, and
+/// should not be used outside of the EDK II tree.
+///
+struct _XENBUS_PROTOCOL {
+  XENBUS_GRANT_ACCESS           GrantAccess;
+  XENBUS_GRANT_END_ACCESS       GrantEndAccess;
+  //
+  // Protocol data fields
+  //
+};
+
+extern EFI_GUID gXenBusProtocolGuid;
+
+#endif

OvmfPkg/OvmfPkg.dec

@@ -47,6 +47,7 @@
 [Protocols]
   gVirtioDeviceProtocolGuid       = {0xfa920010, 0x6785, 0x4941, {0xb6, 0xec, 0x49, 0x8c, 0x57, 0x9f, 0x16, 0x0a}}
   gBlockMmioProtocolGuid          = {0x6b558ce3, 0x69e5, 0x4c67, {0xa6, 0x34, 0xf7, 0xfe, 0x72, 0xad, 0xbe, 0x84}}
+  gXenBusProtocolGuid             = {0x3d3ca290, 0xb9a5, 0x11e3, {0xb7, 0x5d, 0xb8, 0xac, 0x6f, 0x7d, 0x65, 0xe6}}
 
 [PcdsFixedAtBuild]
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfPeiMemFvBase|0x0|UINT32|0

OvmfPkg/XenBusDxe/XenBusDxe.h

@@ -18,6 +18,11 @@
 
 #include <Uefi.h>
 
+//
+// Xen interface version used
+//
+#define  __XEN_INTERFACE_VERSION__ 0x00040400
+
 //
 // Libraries
 //
@@ -45,6 +50,7 @@
 //
 // Produced Protocols
 //
+#include <Protocol/XenBus.h>
 
 
 //

OvmfPkg/XenBusDxe/XenBusDxe.inf

@@ -62,6 +62,7 @@
   gEfiPciIoProtocolGuid
   gEfiComponentName2ProtocolGuid
   gEfiComponentNameProtocolGuid
+  gXenBusProtocolGuid
 
 
 [Guids]