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. > > (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 (#74365): https://edk2.groups.io/g/devel/message/74365 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] -=-=-=-=-=-=-=-=-=-=-=-
