From: Tom Lendacky <thomas.lenda...@amd.com> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198
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.kin...@intel.com> Cc: Liming Gao <liming....@intel.com> Reviewed-by: Liming Gao <liming....@intel.com> Signed-off-by: Tom Lendacky <thomas.lenda...@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 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 + -- 2.27.0 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#63849): https://edk2.groups.io/g/devel/message/63849 Mute This Topic: https://groups.io/mt/76056483/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
