[CHERRY-PICK] UefiCpuPkg/MpInitLib: Use AsmCpuidEx() for CPUID_EXTEND…

…ED_TOPOLOGY leaf

The CPUID_EXTENDED_TOPOLOGY CPUID leaf takes a subleaf as input when
returning CPUID information. However, the AsmCpuid() function does not
zero out ECX before the CPUID instruction, so the input leaf is used as
the sub-leaf for the CPUID request and returns erroneous/invalid CPUID
data, since the intent of the request was to get data related to sub-leaf
0. Instead, use AsmCpuidEx() for the CPUID_EXTENDED_TOPOLOGY leaf.

Fixes: d4d7c9a ("UefiCpuPkg/MpInitLib: use BSP to do extended ...")
Signed-off-by: Tom Lendacky <[email protected]>
Reviewed-by: Ray Ni <[email protected]>

UefiCpuPkg/Library/MpInitLib/AmdSev.c

@@ -284,7 +284,14 @@ FillExchangeInfoDataSevEs (
   if (StdRangeMax >= CPUID_EXTENDED_TOPOLOGY) {
     CPUID_EXTENDED_TOPOLOGY_EBX  ExtTopoEbx;
 
-    AsmCpuid (CPUID_EXTENDED_TOPOLOGY, NULL, &ExtTopoEbx.Uint32, NULL, NULL);
+    AsmCpuidEx (
+      CPUID_EXTENDED_TOPOLOGY,
+      0,
+      NULL,
+      &ExtTopoEbx.Uint32,
+      NULL,
+      NULL
+      );
     ExchangeInfo->ExtTopoAvail = !!ExtTopoEbx.Bits.LogicalProcessors;
   }
 }