OvmfPkg/PlatformPei: Add RAM for Xen in InitializeRamRegions

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15207 6f19259b-4bc3-4df7-8a09-765794883524

OvmfPkg/PlatformPei/MemDetect.c

@@ -168,5 +168,10 @@ InitializeRamRegions (
   VOID
   )
 {
-  QemuInitializeRam ();
+  if (!mXen) {
+    QemuInitializeRam ();
+  } else {
+    DEBUG ((EFI_D_INFO, "Using memory map provided by Xen\n"));
+    XenPublishRamRegions ();
+  }
 }