1 files changed, 32 insertions, 0 deletions
diff --git a/OvmfPkg/Sec/SecMain.c b/OvmfPkg/Sec/SecMain.c
index 60dfa61..b0bb7b2 100644
--- a/OvmfPkg/Sec/SecMain.c
+++ b/OvmfPkg/Sec/SecMain.c
@@ -29,6 +29,8 @@
 #include <Ppi/MpInitLibDep.h>
 #include <Library/TdxHelperLib.h>
 #include <Library/CcProbeLib.h>
+#include <Register/Intel/ArchitecturalMsr.h>
+#include <Register/Intel/Cpuid.h>
 #include "AmdSev.h"
 
 #define SEC_IDT_ENTRY_COUNT  34
@@ -743,6 +745,31 @@ FindAndReportEntryPoints (
   return;
 }
 
+//
+// Enable MTRR early, set default type to write back.
+// Needed to make sure caching is enabled,
+// without this lzma decompress can be very slow.
+//
+STATIC
+VOID
+SecMtrrSetup (
+  VOID
+  )
+{
+  CPUID_VERSION_INFO_EDX           Edx;
+  MSR_IA32_MTRR_DEF_TYPE_REGISTER  DefType;
+
+  AsmCpuid (CPUID_VERSION_INFO, NULL, NULL, NULL, &Edx.Uint32);
+  if (!Edx.Bits.MTRR) {
+    return;
+  }
+
+  DefType.Uint64    = AsmReadMsr64 (MSR_IA32_MTRR_DEF_TYPE);
+  DefType.Bits.Type = 6; /* write back */
+  DefType.Bits.E    = 1; /* enable */
+  AsmWriteMsr64 (MSR_IA32_MTRR_DEF_TYPE, DefType.Uint64);
+}
+
 VOID
 EFIAPI
 SecCoreStartupWithStack (
@@ -943,6 +970,11 @@ SecCoreStartupWithStack (
   DisableApicTimerInterrupt ();
 
   //
+  // Initialize MTRR
+  //
+  SecMtrrSetup ();
+
+  //
   // Initialize Debug Agent to support source level debug in SEC/PEI phases before memory ready.
   //
   InitializeDebugAgent (DEBUG_AGENT_INIT_PREMEM_SEC, &SecCoreData, SecStartupPhase2);