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.
Provide the necessary support to execute the VMGEXIT instruction, which
is "rep; vmmcall".
Cc: Michael D Kinney <michael.d.kin...@intel.com>
Cc: 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/GccInline.c | 17 +++++++++++
MdePkg/Library/BaseLib/X64/GccInline.c | 17 +++++++++++
MdePkg/Library/BaseLib/Ia32/VmgExit.nasm | 37 ++++++++++++++++++++++++
MdePkg/Library/BaseLib/X64/VmgExit.nasm | 32 ++++++++++++++++++++
6 files changed, 119 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 da6bc22a3e2b..7cf6467fa77b 100644
--- a/MdePkg/Library/BaseLib/BaseLib.inf
+++ b/MdePkg/Library/BaseLib/BaseLib.inf
@@ -154,6 +154,7 @@ [Sources.Ia32]
Ia32/EnableCache.c | MSFT
Ia32/DisableCache.c | MSFT
Ia32/XGetBv.nasm | MSFT
+ Ia32/VmgExit.nasm | MSFT
Ia32/GccInline.c | GCC
@@ -289,6 +290,7 @@ [Sources.X64]
X64/ReadCr0.nasm| MSFT
X64/ReadEflags.nasm| MSFT
X64/XGetBv.nasm | MSFT
+ X64/VmgExit.nasm | MSFT
X64/Non-existing.c
diff --git a/MdePkg/Include/Library/BaseLib.h b/MdePkg/Include/Library/BaseLib.h
index 049fd1b872b8..2d131b2ac8a1 100644
--- a/MdePkg/Include/Library/BaseLib.h
+++ b/MdePkg/Include/Library/BaseLib.h
@@ -7959,6 +7959,20 @@ 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/GccInline.c
b/MdePkg/Library/BaseLib/Ia32/GccInline.c
index 591f0bb0e097..ee8c62c79c93 100644
--- a/MdePkg/Library/BaseLib/Ia32/GccInline.c
+++ b/MdePkg/Library/BaseLib/Ia32/GccInline.c
@@ -1791,3 +1791,20 @@ AsmXGetBv (
}
+/**
+ Executes a VMGEXIT instruction.
+
+ Executes a VMGEXIT instruction. This function is only available on IA-32 and
+ X64.
+
+**/
+VOID
+EFIAPI
+AsmVmgExit (
+ VOID
+ )
+{
+ __asm__ __volatile__ ("rep; vmmcall":::"memory");
+}
+
+
diff --git a/MdePkg/Library/BaseLib/X64/GccInline.c
b/MdePkg/Library/BaseLib/X64/GccInline.c
index 3eed1205adb2..277974eff9ee 100644
--- a/MdePkg/Library/BaseLib/X64/GccInline.c
+++ b/MdePkg/Library/BaseLib/X64/GccInline.c
@@ -1828,3 +1828,20 @@ AsmXGetBv (
}
+/**
+ Executes a VMGEXIT instruction.
+
+ Executes a VMGEXIT instruction. This function is only available on IA-32 and
+ X64.
+
+**/
+VOID
+EFIAPI
+AsmVmgExit (
+ VOID
+ )
+{
+ __asm__ __volatile__ ("rep; vmmcall":::"memory");
+}
+
+
diff --git a/MdePkg/Library/BaseLib/Ia32/VmgExit.nasm
b/MdePkg/Library/BaseLib/Ia32/VmgExit.nasm
new file mode 100644
index 000000000000..a4b37385cc7a
--- /dev/null
+++ b/MdePkg/Library/BaseLib/Ia32/VmgExit.nasm
@@ -0,0 +1,37 @@
+;------------------------------------------------------------------------------
+;
+; 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, so work around
+; this by temporarily switching to 64-bit mode.
+;
+BITS 64
+ rep vmmcall
+BITS 32
+ 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
+
--
2.17.1
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