Files
system76-edk2/MdePkg/Library/BaseLib/X64/VmgExit.nasm
Tom Lendacky f8422f1e0b MdePkg/BaseLib: Add support for the VMGEXIT instruction
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.kinney@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
2020-08-16 16:45:42 +00:00

33 lines
725 B
NASM

;------------------------------------------------------------------------------
;
; 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