[edk2-devel] [PATCH 3/6] UefiCpuPkg/MtrrLib: Substract TME-MK KEY_ID_BITS from CPU max PA

[Ni, Ray]

CPUID enumeration of MAX_PA is unaffected by TME-MK activation and
will continue to report the maximum physical address bits available
for software to use, irrespective of the number of KeyID bits.

So, we need to check if TME is enabled and adjust the PA size
accordingly.

Signed-off-by: Ray Ni <ray.ni at intel.com>
Cc: Eric Dong <eric.dong at intel.com>
Cc: Rahul Kumar <rahul1.kumar at intel.com>
Cc: Gerd Hoffmann <kraxel at redhat.com>
Cc: Michael D Kinney <michael.d.kinney at intel.com>
Cc: Ahmad Anadani <ahmad.anadani at intel.com>
---
 UefiCpuPkg/Library/MtrrLib/MtrrLib.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
index e5c862c83d..a66357e305 100644
--- a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
+++ b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
@@ -756,8 +756,11 @@ MtrrLibInitializeMtrrMask (
   OUT UINT64  *MtrrValidAddressMask
   )
 {
-  UINT32                          MaxExtendedFunction;
-  CPUID_VIR_PHY_ADDRESS_SIZE_EAX  VirPhyAddressSize;
+  UINT32                                       MaxExtendedFunction;
+  CPUID_VIR_PHY_ADDRESS_SIZE_EAX               VirPhyAddressSize;
+  UINT32                                       MaxFunction;
+  CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS_ECX  ExtendedFeatureFlagsEcx;
+  MSR_IA32_TME_ACTIVATE_REGISTER               TmeActivate;
 
   AsmCpuid (CPUID_EXTENDED_FUNCTION, &MaxExtendedFunction, NULL, NULL, NULL);
 
@@ -767,6 +770,23 @@ MtrrLibInitializeMtrrMask (
     VirPhyAddressSize.Bits.PhysicalAddressBits = 36;
   }
 
+  //
+  // CPUID enumeration of MAX_PA is unaffected by TME-MK activation and will continue
+  // to report the maximum physical address bits available for software to use,
+  // irrespective of the number of KeyID bits.
+  // So, we need to check if TME is enabled and adjust the PA size accordingly.
+  //
+  AsmCpuid (CPUID_SIGNATURE, &MaxFunction, NULL, NULL, NULL);
+  if (MaxFunction >= CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS) {
+    AsmCpuidEx (CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS, 0, NULL, NULL, &ExtendedFeatureFlagsEcx.Uint32, NULL);
+    if (ExtendedFeatureFlagsEcx.Bits.TME_EN == 1) {
+      TmeActivate.Uint64 = AsmReadMsr64 (MSR_IA32_TME_ACTIVATE);
+      if (TmeActivate.Bits.TmeEnable == 1) {
+        VirPhyAddressSize.Bits.PhysicalAddressBits -= TmeActivate.Bits.MkTmeKeyidBits;
+      }
+    }
+  }
+
   *MtrrValidBitsMask    = LShiftU64 (1, VirPhyAddressSize.Bits.PhysicalAddressBits) - 1;
   *MtrrValidAddressMask = *MtrrValidBitsMask & 0xfffffffffffff000ULL;
 }
-- 
2.39.1.windows.1



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