On 04/22/21 15:35, Tom Lendacky wrote: > On 4/22/21 12:28 AM, Laszlo Ersek wrote: >> On 04/21/21 00:54, Lendacky, Thomas wrote: >>> From: Tom Lendacky <thomas.lenda...@amd.com> >>> >>> BZ: >>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugzilla.tianocore.org%2Fshow_bug.cgi%3Fid%3D3345&data=04%7C01%7Cthomas.lendacky%40amd.com%7C22bf3a3ae9cb4421e93208d9054f79c8%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637546661229697941%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=1EmUDf%2FfuCuu%2BkXPZijzatfliplMhKEQH8kiZ9Z8ZF0%3D&reserved=0 >>> >>> The MOVZX and MOVSX instructions use the ModRM byte in the instruction, >>> but the instruction decoding support was not decoding it. This resulted >>> in invalid decoding and failing of the MMIO operation. Also, when >>> performing the zero-extend or sign-extend operation, the memory operation >>> should be using the size, and not the size enumeration value. >>> >>> Add the ModRM byte decoding for the MOVZX and MOVSX opcodes and use the >>> true data size to perform the extend operations. Additionally, add a >>> DEBUG statement identifying the MMIO address being flagged as encrypted >>> during the MMIO address validation. >>> >>> Fixes: c45f678a1ea2080344e125dc55b14e4b9f98483d >>> Cc: Laszlo Ersek <ler...@redhat.com> >>> Cc: Ard Biesheuvel <ardb+tianoc...@kernel.org> >>> Cc: Jordan Justen <jordan.l.jus...@intel.com> >>> Cc: Brijesh Singh <brijesh.si...@amd.com> >>> Cc: James Bottomley <j...@linux.ibm.com> >>> Cc: Jiewen Yao <jiewen....@intel.com> >>> Cc: Min Xu <min.m...@intel.com> >>> Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com> >>> --- >>> OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c | 7 +++++-- >>> 1 file changed, 5 insertions(+), 2 deletions(-) >>> >>> diff --git a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c >>> b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c >>> index 24259060fd65..273f36499988 100644 >>> --- a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c >>> +++ b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c >>> @@ -643,6 +643,7 @@ ValidateMmioMemory ( >>> // >>> // Any state other than unencrypted is an error, issue a #GP. >>> // >>> + DEBUG ((DEBUG_INFO, "MMIO using encrypted memory: %lx\n", >>> MemoryAddress)); >>> GpEvent.Uint64 = 0; >>> GpEvent.Elements.Vector = GP_EXCEPTION; >>> GpEvent.Elements.Type = GHCB_EVENT_INJECTION_TYPE_EXCEPTION; >> >> (1) This can potentially generate a large number of debug messages; >> please use the DEBUG_VERBOSE log mask. > > Actually, you will see this only once since the code will propagate a GP > and the guest will terminate in this situation.
Ugh, sorry, I must have completely lost track of the context here. I apologize. In that case however, it should be DEBUG_ERROR. Thanks, Laszlo > >> >> (2) "MemoryAddress" has type UINTN, but %lx takes UINT64. Given that >> this is X64-only code, functionally there is no bug, but it's still >> cleaner to pass "(UINT64)MemoryAddress" to %lx. > > Will do. > > Thanks, > Tom > >> >> With that: >> >> Acked-by: Laszlo Ersek <ler...@redhat.com> >> >> Thanks >> Laszlo >> >> >>> @@ -817,6 +818,7 @@ MmioExit ( >>> // fall through >>> // >>> case 0xB7: >>> + DecodeModRm (Regs, InstructionData); >>> Bytes = (Bytes != 0) ? Bytes : 2; >>> >>> Status = ValidateMmioMemory (Ghcb, InstructionData->Ext.RmData, Bytes); >>> @@ -835,7 +837,7 @@ MmioExit ( >>> } >>> >>> Register = GetRegisterPointer (Regs, InstructionData->Ext.ModRm.Reg); >>> - SetMem (Register, InstructionData->DataSize, 0); >>> + SetMem (Register, (UINTN) (1 << InstructionData->DataSize), 0); >>> CopyMem (Register, Ghcb->SharedBuffer, Bytes); >>> break; >>> >>> @@ -848,6 +850,7 @@ MmioExit ( >>> // fall through >>> // >>> case 0xBF: >>> + DecodeModRm (Regs, InstructionData); >>> Bytes = (Bytes != 0) ? Bytes : 2; >>> >>> Status = ValidateMmioMemory (Ghcb, InstructionData->Ext.RmData, Bytes); >>> @@ -878,7 +881,7 @@ MmioExit ( >>> } >>> >>> Register = GetRegisterPointer (Regs, InstructionData->Ext.ModRm.Reg); >>> - SetMem (Register, InstructionData->DataSize, SignByte); >>> + SetMem (Register, (UINTN) (1 << InstructionData->DataSize), SignByte); >>> CopyMem (Register, Ghcb->SharedBuffer, Bytes); >>> break; >>> >>> >> > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#74386): https://edk2.groups.io/g/devel/message/74386 Mute This Topic: https://groups.io/mt/82247952/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
