[edk2-devel] [PATCH v3 2/5] OvmfPkg/VmgExitLib: Add support for new MMIO MOV opcodes
Laszlo Ersek
lersek at redhat.com
Fri Apr 30 16:53:54 UTC 2021
On 04/29/21 19:19, Lendacky, Thomas wrote:
> On 4/29/21 12:12 PM, Tom Lendacky wrote:
>> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3345
>>
>> Enabling TPM support results in guest termination of an SEV-ES guest
>> because it uses MMIO opcodes that are not currently supported.
>>
>> Add support for the new MMIO opcodes (0xA0 - 0xA3), MOV instructions which
>> use a memory offset directly encoded in the instruction. Also, add a DEBUG
>> statement to identify an unsupported MMIO opcode being used.
>>
>> Fixes: c45f678a1ea2080344e125dc55b14e4b9f98483d
>> Cc: Laszlo Ersek <lersek at redhat.com>
>> Cc: Ard Biesheuvel <ardb+tianocore at kernel.org>
>> Cc: Jordan Justen <jordan.l.justen at intel.com>
>> Cc: Brijesh Singh <brijesh.singh at amd.com>
>> Cc: Erdem Aktas <erdemaktas at google.com>
>> Cc: James Bottomley <jejb at linux.ibm.com>
>> Cc: Jiewen Yao <jiewen.yao at intel.com>
>> Cc: Min Xu <min.m.xu at intel.com>
>> Signed-off-by: Tom Lendacky <thomas.lendacky at amd.com>
>
> Sorry, Laszlo, I forgot to include your Acked-by: on this patch.
np
Acked-by: Laszlo Ersek <lersek at redhat.com>
Thanks
Laszlo
>
> Tom
>
>> ---
>> OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c | 111 ++++++++++++++++++++
>> 1 file changed, 111 insertions(+)
>>
>> diff --git a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c
>> index b716541ad170..41b0c8cc5312 100644
>> --- a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c
>> +++ b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c
>> @@ -680,6 +680,7 @@ MmioExit (
>> UINTN Bytes;
>> UINT64 *Register;
>> UINT8 OpCode, SignByte;
>> + UINTN Address;
>>
>> Bytes = 0;
>>
>> @@ -729,6 +730,57 @@ MmioExit (
>> }
>> break;
>>
>> + //
>> + // MMIO write (MOV moffsetX, aX)
>> + //
>> + case 0xA2:
>> + Bytes = 1;
>> + //
>> + // fall through
>> + //
>> + case 0xA3:
>> + Bytes = ((Bytes != 0) ? Bytes :
>> + (InstructionData->DataSize == Size16Bits) ? 2 :
>> + (InstructionData->DataSize == Size32Bits) ? 4 :
>> + (InstructionData->DataSize == Size64Bits) ? 8 :
>> + 0);
>> +
>> + InstructionData->ImmediateSize = (UINTN) (1 << InstructionData->AddrSize);
>> + InstructionData->End += InstructionData->ImmediateSize;
>> +
>> + //
>> + // This code is X64 only, so a possible 8-byte copy to a UINTN is ok.
>> + // Use a STATIC_ASSERT to be certain the code is being built as X64.
>> + //
>> + STATIC_ASSERT (
>> + sizeof (UINTN) == sizeof (UINT64),
>> + "sizeof (UINTN) != sizeof (UINT64), this file must be built as X64"
>> + );
>> +
>> + Address = 0;
>> + CopyMem (
>> + &Address,
>> + InstructionData->Immediate,
>> + InstructionData->ImmediateSize
>> + );
>> +
>> + Status = ValidateMmioMemory (Ghcb, Address, Bytes);
>> + if (Status != 0) {
>> + return Status;
>> + }
>> +
>> + ExitInfo1 = Address;
>> + ExitInfo2 = Bytes;
>> + CopyMem (Ghcb->SharedBuffer, &Regs->Rax, Bytes);
>> +
>> + Ghcb->SaveArea.SwScratch = (UINT64) Ghcb->SharedBuffer;
>> + VmgSetOffsetValid (Ghcb, GhcbSwScratch);
>> + Status = VmgExit (Ghcb, SVM_EXIT_MMIO_WRITE, ExitInfo1, ExitInfo2);
>> + if (Status != 0) {
>> + return Status;
>> + }
>> + break;
>> +
>> //
>> // MMIO write (MOV reg/memX, immX)
>> //
>> @@ -811,6 +863,64 @@ MmioExit (
>> CopyMem (Register, Ghcb->SharedBuffer, Bytes);
>> break;
>>
>> + //
>> + // MMIO read (MOV aX, moffsetX)
>> + //
>> + case 0xA0:
>> + Bytes = 1;
>> + //
>> + // fall through
>> + //
>> + case 0xA1:
>> + Bytes = ((Bytes != 0) ? Bytes :
>> + (InstructionData->DataSize == Size16Bits) ? 2 :
>> + (InstructionData->DataSize == Size32Bits) ? 4 :
>> + (InstructionData->DataSize == Size64Bits) ? 8 :
>> + 0);
>> +
>> + InstructionData->ImmediateSize = (UINTN) (1 << InstructionData->AddrSize);
>> + InstructionData->End += InstructionData->ImmediateSize;
>> +
>> + //
>> + // This code is X64 only, so a possible 8-byte copy to a UINTN is ok.
>> + // Use a STATIC_ASSERT to be certain the code is being built as X64.
>> + //
>> + STATIC_ASSERT (
>> + sizeof (UINTN) == sizeof (UINT64),
>> + "sizeof (UINTN) != sizeof (UINT64), this file must be built as X64"
>> + );
>> +
>> + Address = 0;
>> + CopyMem (
>> + &Address,
>> + InstructionData->Immediate,
>> + InstructionData->ImmediateSize
>> + );
>> +
>> + Status = ValidateMmioMemory (Ghcb, Address, Bytes);
>> + if (Status != 0) {
>> + return Status;
>> + }
>> +
>> + ExitInfo1 = Address;
>> + ExitInfo2 = Bytes;
>> +
>> + Ghcb->SaveArea.SwScratch = (UINT64) Ghcb->SharedBuffer;
>> + VmgSetOffsetValid (Ghcb, GhcbSwScratch);
>> + Status = VmgExit (Ghcb, SVM_EXIT_MMIO_READ, ExitInfo1, ExitInfo2);
>> + if (Status != 0) {
>> + return Status;
>> + }
>> +
>> + if (Bytes == 4) {
>> + //
>> + // Zero-extend for 32-bit operation
>> + //
>> + Regs->Rax = 0;
>> + }
>> + CopyMem (&Regs->Rax, Ghcb->SharedBuffer, Bytes);
>> + break;
>> +
>> //
>> // MMIO read w/ zero-extension ((MOVZX regX, reg/memX)
>> //
>> @@ -888,6 +998,7 @@ MmioExit (
>> break;
>>
>> default:
>> + DEBUG ((DEBUG_ERROR, "Invalid MMIO opcode (%x)\n", OpCode));
>> Status = GP_EXCEPTION;
>> ASSERT (FALSE);
>> }
>>
>
>
>
>
>
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