From: Tom Lendacky <thomas.lenda...@amd.com> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198
Under SEV-ES, a RDTSC intercept generates a #VC exception. VMGEXIT must be used to allow the hypervisor to handle this intercept. Cc: Jordan Justen <jordan.l.jus...@intel.com> Cc: Laszlo Ersek <ler...@redhat.com> Cc: Ard Biesheuvel <ard.biesheu...@arm.com> Acked-by: Laszlo Ersek <ler...@redhat.com> Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com> --- OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c | 43 +++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c index bf07f960e380..65af57046063 100644 --- a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c +++ b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c @@ -1221,6 +1221,45 @@ CpuidExit ( return 0; } +/** + Handle a RDTSC event. + + Use the VMGEXIT instruction to handle a RDTSC 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 +RdtscExit ( + IN OUT GHCB *Ghcb, + IN OUT EFI_SYSTEM_CONTEXT_X64 *Regs, + IN SEV_ES_INSTRUCTION_DATA *InstructionData + ) +{ + UINT64 Status; + + Status = VmgExit (Ghcb, SVM_EXIT_RDTSC, 0, 0); + if (Status != 0) { + return Status; + } + + if (!GhcbIsRegValid (Ghcb, GhcbRax) || + !GhcbIsRegValid (Ghcb, GhcbRdx)) { + return UnsupportedExit (Ghcb, Regs, InstructionData); + } + Regs->Rax = Ghcb->SaveArea.Rax; + Regs->Rdx = Ghcb->SaveArea.Rdx; + + return 0; +} + /** Handle a #VC exception. @@ -1265,6 +1304,10 @@ VmgExitHandleVc ( ExitCode = Regs->ExceptionData; switch (ExitCode) { + case SVM_EXIT_RDTSC: + NaeExit = RdtscExit; + break; + case SVM_EXIT_CPUID: NaeExit = CpuidExit; break; -- 2.27.0 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#62522): https://edk2.groups.io/g/devel/message/62522 Mute This Topic: https://groups.io/mt/75499861/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-