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| author | Tom Lendacky <thomas.lendacky@amd.com> | 2020-08-12 15:21:37 -0500 |
|---|---|---|
| committer | mergify[bot] <37929162+mergify[bot]@users.noreply.github.com> | 2020-08-17 02:46:39 +0000 |
| commit | 9711c9230b5485e3e652b21c5eb6da0e07e6394c (patch) | |
| tree | 4ec8121bbaf26f8d75f28e0479bb4666424797c6 | |
| parent | 6587e08d3a618facf69da6515ce0dd918d1464ea (diff) | |
| download | edk2-9711c9230b5485e3e652b21c5eb6da0e07e6394c.tar.gz edk2-9711c9230b5485e3e652b21c5eb6da0e07e6394c.tar.bz2 edk2-9711c9230b5485e3e652b21c5eb6da0e07e6394c.zip | |
OvmfPkg/VmgExitLib: Add support for MSR_PROT NAE events
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198
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.
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
| -rw-r--r-- | OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c index 476e94ce5f..f6cfd7fa29 100644 --- a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c +++ b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c @@ -375,6 +375,67 @@ UnsupportedExit ( }
/**
+ Handle an MSR event.
+
+ Use the VMGEXIT instruction to handle either a RDMSR or WRMSR event.
+
+ @param[in, out] Ghcb Pointer to the Guest-Hypervisor Communication
+ Block
+ @param[in, out] Regs x64 processor context
+ @param[in] InstructionData Instruction parsing context
+
+ @retval 0 Event handled successfully
+ @return New exception value to propagate
+
+**/
+STATIC
+UINT64
+MsrExit (
+ IN OUT GHCB *Ghcb,
+ IN OUT EFI_SYSTEM_CONTEXT_X64 *Regs,
+ IN SEV_ES_INSTRUCTION_DATA *InstructionData
+ )
+{
+ UINT64 ExitInfo1, 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);
+ //
+ // fall through
+ //
+ case 0x32: // RDMSR
+ Ghcb->SaveArea.Rcx = Regs->Rcx;
+ GhcbSetRegValid (Ghcb, GhcbRcx);
+ break;
+ default:
+ return UnsupportedExit (Ghcb, Regs, InstructionData);
+ }
+
+ Status = VmgExit (Ghcb, SVM_EXIT_MSR, ExitInfo1, 0);
+ if (Status != 0) {
+ return Status;
+ }
+
+ if (ExitInfo1 == 0) {
+ if (!GhcbIsRegValid (Ghcb, GhcbRax) ||
+ !GhcbIsRegValid (Ghcb, GhcbRdx)) {
+ return UnsupportedExit (Ghcb, Regs, InstructionData);
+ }
+ Regs->Rax = Ghcb->SaveArea.Rax;
+ Regs->Rdx = Ghcb->SaveArea.Rdx;
+ }
+
+ return 0;
+}
+
+/**
Build the IOIO event information.
The IOIO event information identifies the type of IO operation to be performed
@@ -705,6 +766,10 @@ VmgExitHandleVc ( NaeExit = IoioExit;
break;
+ case SVM_EXIT_MSR:
+ NaeExit = MsrExit;
+ break;
+
default:
NaeExit = UnsupportedExit;
}
|