[PATCH v3 13/35] OvmfPkg/Library/XenPlatformLib: New library

["Anthony PERARD" <anthony.perard@citrix.com>]

The purpose of XenPlatformLib is to regroup the few functions that are
used in several places to detect if Xen is detected, and to get the
XenInfo HOB.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1689
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---

Notes:
    v3:
    - use SPDX
    - add XenPlatformLib.h to [LibraryClasses] in OvmfPkg.dec
    - fix typos

 OvmfPkg/OvmfPkg.dec                           |  4 ++
 OvmfPkg/OvmfXen.dsc                           |  1 +
 .../Library/XenPlatformLib/XenPlatformLib.inf | 33 +++++++++
 OvmfPkg/Include/Library/XenPlatformLib.h      | 53 ++++++++++++++
 .../Library/XenPlatformLib/XenPlatformLib.c   | 69 +++++++++++++++++++
 5 files changed, 160 insertions(+)
 create mode 100644 OvmfPkg/Library/XenPlatformLib/XenPlatformLib.inf
 create mode 100644 OvmfPkg/Include/Library/XenPlatformLib.h
 create mode 100644 OvmfPkg/Library/XenPlatformLib/XenPlatformLib.c

diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index c2a2ebfb95..04d5e29272 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -70,6 +70,10 @@ [LibraryClasses]
   #
   XenIoMmioLib|Include/Library/XenIoMmioLib.h
 
+  ##  @libraryclass  Get information about Xen
+  #
+  XenPlatformLib|Include/Library/XenPlatformLib.h
+
 [Guids]
   gUefiOvmfPkgTokenSpaceGuid          = {0x93bb96af, 0xb9f2, 0x4eb8, {0x94, 0x62, 0xe0, 0xba, 0x74, 0x56, 0x42, 0x36}}
   gEfiXenInfoGuid                     = {0xd3b46f3b, 0xd441, 0x1244, {0x9a, 0x12, 0x0, 0x12, 0x27, 0x3f, 0xc1, 0x4d}}
diff --git a/OvmfPkg/OvmfXen.dsc b/OvmfPkg/OvmfXen.dsc
index 6288394eb8..68d82da7aa 100644
--- a/OvmfPkg/OvmfXen.dsc
+++ b/OvmfPkg/OvmfXen.dsc
@@ -195,6 +195,7 @@ [LibraryClasses]
   SmbusLib|MdePkg/Library/BaseSmbusLibNull/BaseSmbusLibNull.inf
   OrderedCollectionLib|MdePkg/Library/BaseOrderedCollectionRedBlackTreeLib/BaseOrderedCollectionRedBlackTreeLib.inf
   XenHypercallLib|OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf
+  XenPlatformLib|OvmfPkg/Library/XenPlatformLib/XenPlatformLib.inf
 
   Tcg2PhysicalPresenceLib|OvmfPkg/Library/Tcg2PhysicalPresenceLibNull/DxeTcg2PhysicalPresenceLib.inf
 
diff --git a/OvmfPkg/Library/XenPlatformLib/XenPlatformLib.inf b/OvmfPkg/Library/XenPlatformLib/XenPlatformLib.inf
new file mode 100644
index 0000000000..32adb246d6
--- /dev/null
+++ b/OvmfPkg/Library/XenPlatformLib/XenPlatformLib.inf
@@ -0,0 +1,33 @@
+## @file
+#  Get information about Xen
+#
+#  This library simply allow to find out if OVMF is running under Xen and
+#  allow to get more information when it is the case.
+#
+#  Copyright (c) 2019, Citrix Systems, Inc.
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = XenPlatformLib
+  FILE_GUID                      = DB54DBB7-8142-4EE5-9364-78C824B582EB
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = XenPlatformLib
+
+[Sources]
+  XenPlatformLib.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+
+[LibraryClasses]
+  HobLib
+
+[Guids]
+  gEfiXenInfoGuid
diff --git a/OvmfPkg/Include/Library/XenPlatformLib.h b/OvmfPkg/Include/Library/XenPlatformLib.h
new file mode 100644
index 0000000000..a8347602b7
--- /dev/null
+++ b/OvmfPkg/Include/Library/XenPlatformLib.h
@@ -0,0 +1,53 @@
+/** @file
+*  Get information about Xen
+*
+*  This library simply allow to find out if OVMF is running under Xen and
+*  allow to get more information when it is the case.
+*
+*  Copyright (c) 2019, Citrix Systems, Inc.
+*
+*  SPDX-License-Identifier: BSD-2-Clause-Patent
+*
+**/
+
+#ifndef _XEN_PLATFORM_LIB_H_
+#define _XEN_PLATFORM_LIB_H_
+
+#include <Guid/XenInfo.h>
+
+/**
+  This function detects if OVMF is running on Xen.
+
+  @retval TRUE    OVMF is running on Xen
+  @retval FALSE   Xen has not been detected
+**/
+BOOLEAN
+EFIAPI
+XenDetected (
+  VOID
+  );
+
+/**
+  This function detect if OVMF have started via the PVH entry point.
+
+  @retval TRUE  PVH entry point as been used
+  @retval FALSE OVMF have started via the HVM route
+**/
+BOOLEAN
+EFIAPI
+XenPvhDetected (
+  VOID
+  );
+
+/**
+  This function return a pointer to the XenInfo HOB.
+
+  @return  XenInfo pointer or NULL if not available
+**/
+EFI_XEN_INFO *
+EFIAPI
+XenGetInfoHOB (
+  VOID
+  );
+
+#endif
diff --git a/OvmfPkg/Library/XenPlatformLib/XenPlatformLib.c b/OvmfPkg/Library/XenPlatformLib/XenPlatformLib.c
new file mode 100644
index 0000000000..6f27cbffa8
--- /dev/null
+++ b/OvmfPkg/Library/XenPlatformLib/XenPlatformLib.c
@@ -0,0 +1,69 @@
+/** @file
+*  Get information about Xen
+*
+*  This library simply allow to find out if OVMF is running under Xen and
+*  allow to get more information when it is the case.
+*
+*  Copyright (c) 2019, Citrix Systems, Inc.
+*
+*  SPDX-License-Identifier: BSD-2-Clause-Patent
+*
+**/
+
+#include <PiDxe.h>
+#include <Library/HobLib.h>
+#include <Library/XenPlatformLib.h>
+
+/**
+  This function return a pointer to the XenInfo HOB.
+
+  @return  XenInfo pointer or NULL if not available
+**/
+EFI_XEN_INFO *
+EFIAPI
+XenGetInfoHOB (
+  VOID
+  )
+{
+  EFI_HOB_GUID_TYPE  *GuidHob;
+
+  GuidHob = GetFirstGuidHob (&gEfiXenInfoGuid);
+  if (GuidHob == NULL) {
+    return NULL;
+  }
+
+  return (EFI_XEN_INFO *) GET_GUID_HOB_DATA (GuidHob);
+}
+
+/**
+  This function detects if OVMF is running on Xen.
+
+  @retval TRUE    OVMF is running on Xen
+  @retval FALSE   Xen has not been detected
+**/
+BOOLEAN
+EFIAPI
+XenDetected (
+  VOID
+  )
+{
+  return (XenGetInfoHOB () != NULL);
+}
+
+/**
+  This function detect if OVMF have started via the PVH entry point.
+
+  @retval TRUE  PVH entry point as been used
+  @retval FALSE OVMF have started via the HVM route
+**/
+BOOLEAN
+EFIAPI
+XenPvhDetected (
+  VOID
+  )
+{
+  EFI_XEN_INFO        *XenInfo;
+
+  XenInfo = XenGetInfoHOB ();
+  return (XenInfo != NULL && XenInfo->RsdpPvh != NULL);
+}
-- 
Anthony PERARD