[PATCH v2 15/31] OvmfPkg/XenHypercallLib: Enable it in PEIM

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

Allow to use Xen hypercalls earlier, during the PEIM stage, but
XenHypercallLibReInit() must be called once the XenInfo HOB is created
with the HyperPage setup.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---
 OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf |  2 +-
 OvmfPkg/XenPlatformPei/XenPlatformPei.inf           |  1 +
 OvmfPkg/Include/Library/XenHypercallLib.h           | 12 ++++++++++++
 OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c   | 11 +++++++++++
 OvmfPkg/XenPlatformPei/Xen.c                        |  7 +++++++
 5 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf b/OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf
index d268e540fe..e0a1889171 100644
--- a/OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf
+++ b/OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf
@@ -21,7 +21,7 @@ [Defines]
   CONSTRUCTOR                    = XenHypercallLibInit
 
 [Defines.IA32, Defines.X64]
-  LIBRARY_CLASS                  = XenHypercallLib|DXE_DRIVER UEFI_DRIVER
+  LIBRARY_CLASS                  = XenHypercallLib|PEIM DXE_DRIVER UEFI_DRIVER
 
 [Defines.ARM, Defines.AARCH64]
   LIBRARY_CLASS                  = XenHypercallLib
diff --git a/OvmfPkg/XenPlatformPei/XenPlatformPei.inf b/OvmfPkg/XenPlatformPei/XenPlatformPei.inf
index 1870e39208..bc6065a709 100644
--- a/OvmfPkg/XenPlatformPei/XenPlatformPei.inf
+++ b/OvmfPkg/XenPlatformPei/XenPlatformPei.inf
@@ -66,6 +66,7 @@ [LibraryClasses]
   MtrrLib
   MemEncryptSevLib
   PcdLib
+  XenHypercallLib
 
 [Pcd]
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfPeiMemFvBase
diff --git a/OvmfPkg/Include/Library/XenHypercallLib.h b/OvmfPkg/Include/Library/XenHypercallLib.h
index 36e3344e2f..38e64ab108 100644
--- a/OvmfPkg/Include/Library/XenHypercallLib.h
+++ b/OvmfPkg/Include/Library/XenHypercallLib.h
@@ -16,6 +16,18 @@
 #ifndef __XEN_HYPERCALL_LIB_H__
 #define __XEN_HYPERCALL_LIB_H__
 
+/**
+  To call when the gEfiXenInfoGuid HOB became available after the library init
+  function has already been executed.
+
+  This allow to make hypercall in the PEIM stage.
+**/
+VOID
+EFIAPI
+XenHypercallLibReInit (
+  VOID
+  );
+
 /**
   Check if the Xen Hypercall library is able to make calls to the Xen
   hypervisor.
diff --git a/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c b/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c
index 7cb7f46c9b..2ac7254759 100644
--- a/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c
+++ b/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c
@@ -78,6 +78,17 @@ XenHypercallLibInit (
   return RETURN_SUCCESS;
 }
 
+VOID
+EFIAPI
+XenHypercallLibReInit (
+  VOID
+  )
+{
+  if (HyperPage == NULL) {
+    XenHypercallLibInit();
+  }
+}
+
 /**
   This function will put the two arguments in the right place (registers) and
   invoke the hypercall identified by HypercallID.
diff --git a/OvmfPkg/XenPlatformPei/Xen.c b/OvmfPkg/XenPlatformPei/Xen.c
index fb01094ba9..9d9e9f8020 100644
--- a/OvmfPkg/XenPlatformPei/Xen.c
+++ b/OvmfPkg/XenPlatformPei/Xen.c
@@ -32,6 +32,7 @@
 #include <Library/ResourcePublicationLib.h>
 #include <Library/MtrrLib.h>
 #include <IndustryStandard/Xen/arch-x86/hvm/start_info.h>
+#include <Library/XenHypercallLib.h>
 
 #include "Platform.h"
 #include "Xen.h"
@@ -157,6 +158,12 @@ XenConnect (
     sizeof(mXenInfo)
     );
 
+  //
+  // Initialize the XenHypercall library, now that the XenInfo HOB is
+  // available
+  //
+  XenHypercallLibReInit ();
+
   return EFI_SUCCESS;
 }
 
-- 
Anthony PERARD