From: Tom Lendacky <thomas.lenda...@amd.com>
Under SEV-ES, a MSR_PROT intercept generates a #VC exception. VMGEXIT must
be used to allow the hypervisor to handle this intercept.
Add support to construct the required GHCB values to support an MSR_PROT
NAE event. Parse the instruction that generated the #VC exception to
determine whether it is RDMSR or WRMSR, setting the required register
register values in the GHCB and creating the proper SW_EXIT_INFO1 value in
the GHCB.
Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com>
---
.../X64/AMDSevVcCommon.c | 52 +++++++++++++++++++
1 file changed, 52 insertions(+)
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/AMDSevVcCommon.c
b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/AMDSevVcCommon.c
index 66cd0f9eb196..2b25919ea496 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/AMDSevVcCommon.c
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/AMDSevVcCommon.c
@@ -251,6 +251,54 @@ UnsupportedExit (
return Status;
}
+STATIC
+UINTN
+MsrExit (
+ GHCB *Ghcb,
+ EFI_SYSTEM_CONTEXT_X64 *Regs,
+ SEV_ES_INSTRUCTION_DATA *InstructionData
+ )
+{
+ UINT64 ExitInfo1;
+ UINTN Status;
+
+ ExitInfo1 = 0;
+
+ switch (*(InstructionData->OpCodes + 1)) {
+ case 0x30: // WRMSR
+ ExitInfo1 = 1;
+ Ghcb->SaveArea.Rax = Regs->Rax;
+ GhcbSetRegValid (Ghcb, GhcbRax);
+ Ghcb->SaveArea.Rdx = Regs->Rdx;
+ GhcbSetRegValid (Ghcb, GhcbRdx);
+ /* Fallthrough */
+ case 0x32: // RDMSR
+ Ghcb->SaveArea.Rcx = Regs->Rcx;
+ GhcbSetRegValid (Ghcb, GhcbRcx);
+ break;
+ default:
+ VmgExit (Ghcb, SvmExitUnsupported, SvmExitMsr, 0);
+ ASSERT (0);
+ }
+
+ Status = VmgExit (Ghcb, SvmExitMsr, ExitInfo1, 0);
+ if (Status) {
+ return Status;
+ }
+
+ if (!ExitInfo1) {
+ if (!GhcbIsRegValid (Ghcb, GhcbRax) ||
+ !GhcbIsRegValid (Ghcb, GhcbRdx)) {
+ VmgExit (Ghcb, SvmExitUnsupported, SvmExitMsr, 0);
+ ASSERT (0);
+ }
+ Regs->Rax = Ghcb->SaveArea.Rax;
+ Regs->Rdx = Ghcb->SaveArea.Rdx;
+ }
+
+ return 0;
+}
+
#define IOIO_TYPE_STR (1 << 2)
#define IOIO_TYPE_IN 1
#define IOIO_TYPE_INS (IOIO_TYPE_IN | IOIO_TYPE_STR)
@@ -538,6 +586,10 @@ DoVcCommon (
NaeExit = IoioExit;
break;
+ case SvmExitMsr:
+ NaeExit = MsrExit;
+ break;
+
default:
NaeExit = UnsupportedExit;
}
--
2.17.1
-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#46114): https://edk2.groups.io/g/devel/message/46114
Mute This Topic: https://groups.io/mt/32966286/21656
Group Owner: devel+ow...@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com]
-=-=-=-=-=-=-=-=-=-=-=-
