BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198

Under SEV-ES, a VMMCALL intercept generates a #VC exception. VMGEXIT must
be used to allow the hypervisor to handle this intercept.

Cc: Eric Dong <eric.dong@...>
Cc: Ray Ni <ray.ni@...>
Cc: Laszlo Ersek <lersek@...>
Signed-off-by: Tom Lendacky <thomas.lendacky@...>
---
.../X64/ArchAMDSevVcHandler.c | 34 +++++++++++++++++++
1 file changed, 34 insertions(+)

diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchAMDSevVcHandler.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchAMDSevVcHandler.c
index a0dd5e2adcc9..354d027f08f3 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchAMDSevVcHandler.c
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchAMDSevVcHandler.c
@@ -609,6 +609,36 @@ WbinvdExit (
return 0;
}

+STATIC
+UINT64
+VmmCallExit (
+ GHCB *Ghcb,
+ EFI_SYSTEM_CONTEXT_X64 *Regs,
+ SEV_ES_INSTRUCTION_DATA *InstructionData
+ )
+{
+ UINT64 Status;
+
+ DecodeModRm (Regs, InstructionData);
+
+ Ghcb->SaveArea.Rax = Regs->Rax;
+ GhcbSetRegValid (Ghcb, GhcbRax);
+ Ghcb->SaveArea.Cpl = (UINT8) (Regs->Cs & 0x3);
+ GhcbSetRegValid (Ghcb, GhcbCpl);
+
+ Status = VmgExit (Ghcb, SvmExitVmmCall, 0, 0);
+ if (Status) {
+ return Status;
+ }
+
+ if (!GhcbIsRegValid (Ghcb, GhcbRax)) {
+ return UnsupportedExit (Ghcb, Regs, InstructionData);
+ }
+ Regs->Rax = Ghcb->SaveArea.Rax;
+
+ return 0;
+}
+
STATIC
UINT64
MsrExit (
@@ -1005,6 +1035,10 @@ DoVcCommon (
NaeExit = MsrExit;
break;

+ case SvmExitVmmCall:
+ NaeExit = VmmCallExit;
+ break;
+
case SvmExitWbinvd:
NaeExit = WbinvdExit;
break;
--
2.17.1