[edk2-devel] [PATCH v14 07/46] MdePkg/BaseLib: Add support for the VMGEXIT instruction
Lendacky, Thomas
thomas.lendacky at amd.com
Mon Aug 10 19:12:44 UTC 2020
On 8/10/20 1:47 PM, Laszlo Ersek wrote:
> Hi Tom,
Hi Laszlo,
>
> On 08/07/20 21:38, Lendacky, Thomas wrote:
>> From: Tom Lendacky <thomas.lendacky at amd.com>
>>
>> BZ: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugzilla.tianocore.org%2Fshow_bug.cgi%3Fid%3D2198&data=02%7C01%7Cthomas.lendacky%40amd.com%7C243b5723f67c4fe89ed008d83d5dd5db%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637326820522631996&sdata=vyh1QG9W%2Fi%2FOHrjG6oiOySzF6B5%2BTi76pZ2UYAH5e3M%3D&reserved=0
>>
>> VMGEXIT is a new instruction used for Hypervisor/Guest communication when
>> running as an SEV-ES guest. A VMGEXIT will cause an automatic exit (AE)
>> to occur, resulting in a #VMEXIT with an exit code value of 0x403.
>>
>> Since SEV-ES is only supported in X64, provide the necessary X64 support
>> to execute the VMGEXIT instruction, which is coded as "rep vmmcall". For
>> IA32, since "vmmcall" is not supported in NASM 32-bit mode and VMGEXIT
>> should never be called, provide a stub implementation that is identical
>> to CpuBreakpoint().
>>
>> Cc: Michael D Kinney <michael.d.kinney at intel.com>
>> Cc: Liming Gao <liming.gao at intel.com>
>> Reviewed-by: Liming Gao <liming.gao at intel.com>
>> Signed-off-by: Tom Lendacky <thomas.lendacky at amd.com>
>> ---
>> MdePkg/Library/BaseLib/BaseLib.inf | 2 ++
>> MdePkg/Include/Library/BaseLib.h | 14 +++++++++
>> MdePkg/Library/BaseLib/Ia32/VmgExit.nasm | 38 ++++++++++++++++++++++++
>> MdePkg/Library/BaseLib/X64/VmgExit.nasm | 32 ++++++++++++++++++++
>> 4 files changed, 86 insertions(+)
>> create mode 100644 MdePkg/Library/BaseLib/Ia32/VmgExit.nasm
>> create mode 100644 MdePkg/Library/BaseLib/X64/VmgExit.nasm
>
> this patch is identical to the one in v13, but you forgot to pick up my:
>
> Reviewed-by: Laszlo Ersek <lersek at redhat.com>
Yup, sorry about that, I missed it.
Thanks,
Tom
>
> from:
>
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fedk2.groups.io%2Fg%2Fdevel%2Fmessage%2F63568&data=02%7C01%7Cthomas.lendacky%40amd.com%7C243b5723f67c4fe89ed008d83d5dd5db%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637326820522631996&sdata=jWS0M5i780Nt53YX6CjEdIxP51CNhYhEo3qReHJUQvw%3D&reserved=0
> https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmid.mail-archive.com%2F98ff9331-c73b-07f9-de49-f08365c6e003%40redhat.com&data=02%7C01%7Cthomas.lendacky%40amd.com%7C243b5723f67c4fe89ed008d83d5dd5db%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637326820522631996&sdata=ZZHmJPS9MNeEqI08WDDgPwnwsi8TPV7JjyPgziseYm4%3D&reserved=0
>
> Liming, when you push this series, please add my R-b to the commit
> message on this patch.
>
> Thanks
> Laszlo
>
>>
>> diff --git a/MdePkg/Library/BaseLib/BaseLib.inf b/MdePkg/Library/BaseLib/BaseLib.inf
>> index 3b93b5db8d24..3b85c56c3c03 100644
>> --- a/MdePkg/Library/BaseLib/BaseLib.inf
>> +++ b/MdePkg/Library/BaseLib/BaseLib.inf
>> @@ -184,6 +184,7 @@ [Sources.Ia32]
>> Ia32/DisableCache.nasm| GCC
>> Ia32/RdRand.nasm
>> Ia32/XGetBv.nasm
>> + Ia32/VmgExit.nasm
>>
>> Ia32/DivS64x64Remainder.c
>> Ia32/InternalSwitchStack.c | MSFT
>> @@ -317,6 +318,7 @@ [Sources.X64]
>> X64/DisablePaging64.nasm
>> X64/RdRand.nasm
>> X64/XGetBv.nasm
>> + X64/VmgExit.nasm
>> ChkStkGcc.c | GCC
>>
>> [Sources.EBC]
>> diff --git a/MdePkg/Include/Library/BaseLib.h b/MdePkg/Include/Library/BaseLib.h
>> index 7edf0051a0a0..04fb329eaabb 100644
>> --- a/MdePkg/Include/Library/BaseLib.h
>> +++ b/MdePkg/Include/Library/BaseLib.h
>> @@ -7848,6 +7848,20 @@ AsmXGetBv (
>> );
>>
>>
>> +/**
>> + Executes a VMGEXIT instruction (VMMCALL with a REP prefix)
>> +
>> + Executes a VMGEXIT instruction. This function is only available on IA-32 and
>> + x64.
>> +
>> +**/
>> +VOID
>> +EFIAPI
>> +AsmVmgExit (
>> + VOID
>> + );
>> +
>> +
>> /**
>> Patch the immediate operand of an IA32 or X64 instruction such that the byte,
>> word, dword or qword operand is encoded at the end of the instruction's
>> diff --git a/MdePkg/Library/BaseLib/Ia32/VmgExit.nasm b/MdePkg/Library/BaseLib/Ia32/VmgExit.nasm
>> new file mode 100644
>> index 000000000000..69f7fbf3506a
>> --- /dev/null
>> +++ b/MdePkg/Library/BaseLib/Ia32/VmgExit.nasm
>> @@ -0,0 +1,38 @@
>> +;------------------------------------------------------------------------------
>> +;
>> +; Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
>> +; SPDX-License-Identifier: BSD-2-Clause-Patent
>> +;
>> +; Module Name:
>> +;
>> +; VmgExit.Asm
>> +;
>> +; Abstract:
>> +;
>> +; AsmVmgExit function
>> +;
>> +; Notes:
>> +;
>> +;------------------------------------------------------------------------------
>> +
>> + SECTION .text
>> +
>> +;------------------------------------------------------------------------------
>> +; VOID
>> +; EFIAPI
>> +; AsmVmgExit (
>> +; VOID
>> +; );
>> +;------------------------------------------------------------------------------
>> +global ASM_PFX(AsmVmgExit)
>> +ASM_PFX(AsmVmgExit):
>> +;
>> +; NASM doesn't support the vmmcall instruction in 32-bit mode and NASM versions
>> +; before 2.12 cannot translate the 64-bit "rep vmmcall" instruction into elf32
>> +; format. Given that VMGEXIT does not make sense on IA32, provide a stub
>> +; implementation that is identical to CpuBreakpoint(). In practice, AsmVmgExit()
>> +; should never be called on IA32.
>> +;
>> + int 3
>> + ret
>> +
>> diff --git a/MdePkg/Library/BaseLib/X64/VmgExit.nasm b/MdePkg/Library/BaseLib/X64/VmgExit.nasm
>> new file mode 100644
>> index 000000000000..26f034593c67
>> --- /dev/null
>> +++ b/MdePkg/Library/BaseLib/X64/VmgExit.nasm
>> @@ -0,0 +1,32 @@
>> +;------------------------------------------------------------------------------
>> +;
>> +; Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
>> +; SPDX-License-Identifier: BSD-2-Clause-Patent
>> +;
>> +; Module Name:
>> +;
>> +; VmgExit.Asm
>> +;
>> +; Abstract:
>> +;
>> +; AsmVmgExit function
>> +;
>> +; Notes:
>> +;
>> +;------------------------------------------------------------------------------
>> +
>> + DEFAULT REL
>> + SECTION .text
>> +
>> +;------------------------------------------------------------------------------
>> +; VOID
>> +; EFIAPI
>> +; AsmVmgExit (
>> +; VOID
>> +; );
>> +;------------------------------------------------------------------------------
>> +global ASM_PFX(AsmVmgExit)
>> +ASM_PFX(AsmVmgExit):
>> + rep vmmcall
>> + ret
>> +
>>
>
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