OvmfPkg/XenPlatformPei: Remove Hypercall Page

XenHypercallLib now makes direct hypercalls, so HyperPages is
unnecessary and can be removed.

Change the XenPvhDetected() ASSERT to use the Xen version.  That has
never been 0, AFAIK.

Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>

OvmfPkg/Include/Guid/XenInfo.h

@@ -13,10 +13,6 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
     { 0xd3b46f3b, 0xd441, 0x1244, {0x9a, 0x12, 0x0, 0x12, 0x27, 0x3f, 0xc1, 0x4d } }
 
 typedef struct {
-  ///
-  /// Beginning of the hypercall page.
-  ///
-  VOID      *HyperPages;
   ///
   /// Hypervisor major version.
   ///

OvmfPkg/XenPlatformPei/Xen.c

@@ -128,9 +128,6 @@ EFI_STATUS
 XenConnect (
   )
 {
-  UINT32             Index;
-  UINT32             TransferReg;
-  UINT32             TransferPages;
   UINT32             XenVersion;
   EFI_XEN_OVMF_INFO  *Info;
   CHAR8              Sig[sizeof (Info->Signature) + 1];
@@ -139,24 +136,6 @@ XenConnect (
 
   ASSERT (mXenLeaf != 0);
 
-  //
-  // Prepare HyperPages to be able to make hypercalls
-  //
-
-  AsmCpuid (mXenLeaf + 2, &TransferPages, &TransferReg, NULL, NULL);
-  mXenInfo.HyperPages = AllocatePages (TransferPages);
-  if (!mXenInfo.HyperPages) {
-    return EFI_OUT_OF_RESOURCES;
-  }
-
-  for (Index = 0; Index < TransferPages; Index++) {
-    AsmWriteMsr64 (
-      TransferReg,
-      (UINTN)mXenInfo.HyperPages +
-      (Index << EFI_PAGE_SHIFT) + Index
-      );
-  }
-
   //
   // Find out the Xen version
   //
@@ -283,7 +262,7 @@ XenPvhDetected (
   //
   // This function should only be used after XenConnect
   //
-  ASSERT (mXenInfo.HyperPages != NULL);
+  ASSERT (mXenInfo.VersionMajor);
 
   return mXenHvmloaderInfo == NULL;
 }