BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198
Under SEV-ES, a CPUID instruction requires the current value of the XCR0
register. In order to retrieve that value, the XGETBV instruction needs
to be executed.
Provide the necessary support to execute the XGETBV instruction.
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 | 17 ++++++++++
MdePkg/Library/BaseLib/Ia32/GccInline.c | 28 ++++++++++++++++
MdePkg/Library/BaseLib/X64/GccInline.c | 30 +++++++++++++++++
MdePkg/Library/BaseLib/Ia32/XGetBv.nasm | 31 ++++++++++++++++++
MdePkg/Library/BaseLib/X64/XGetBv.nasm | 34 ++++++++++++++++++++
6 files changed, 142 insertions(+)
diff --git a/MdePkg/Library/BaseLib/BaseLib.inf
b/MdePkg/Library/BaseLib/BaseLib.inf
index a57ae2da31f3..da6bc22a3e2b 100644
--- a/MdePkg/Library/BaseLib/BaseLib.inf
+++ b/MdePkg/Library/BaseLib/BaseLib.inf
@@ -153,6 +153,7 @@ [Sources.Ia32]
Ia32/ARShiftU64.c | MSFT
Ia32/EnableCache.c | MSFT
Ia32/DisableCache.c | MSFT
+ Ia32/XGetBv.nasm | MSFT
Ia32/GccInline.c | GCC
@@ -287,6 +288,7 @@ [Sources.X64]
X64/ReadCr2.nasm| MSFT
X64/ReadCr0.nasm| MSFT
X64/ReadEflags.nasm| MSFT
+ X64/XGetBv.nasm | MSFT
X64/Non-existing.c
diff --git a/MdePkg/Include/Library/BaseLib.h b/MdePkg/Include/Library/BaseLib.h
index 8e7b87cbda4e..7edf0051a0a0 100644
--- a/MdePkg/Include/Library/BaseLib.h
+++ b/MdePkg/Include/Library/BaseLib.h
@@ -7831,6 +7831,23 @@ AsmLfence (
VOID
);
+/**
+ Executes a XGETBV instruction
+
+ Executes a XGETBV instruction. This function is only available on IA-32 and
+ x64.
+
+ @param[in] Index Extended control register index
+
+ @return The current value of the extended control register
+**/
+UINT64
+EFIAPI
+AsmXGetBv (
+ IN UINT32 Index
+ );
+
+
/**
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 5287200f8754..c962bcfa4617 100644
--- a/MdePkg/Library/BaseLib/Ia32/GccInline.c
+++ b/MdePkg/Library/BaseLib/Ia32/GccInline.c
@@ -1763,3 +1763,31 @@ AsmFlushCacheLine (
}
+/**
+ Executes a XGETBV instruction
+
+ Executes a XGETBV instruction. This function is only available on IA-32 and
+ x64.
+
+ @param[in] Index Extended control register index
+
+ @return The current value of the extended control register
+**/
+UINT64
+EFIAPI
+AsmXGetBv (
+ IN UINT32 Index
+ )
+{
+ UINT64 Data;
+
+ __asm__ __volatile__ (
+ "xgetbv"
+ : "=A" (Data)
+ : "c" (Index)
+ );
+
+ return Data;
+}
+
+
diff --git a/MdePkg/Library/BaseLib/X64/GccInline.c
b/MdePkg/Library/BaseLib/X64/GccInline.c
index 154ce1f57e92..915555198f9f 100644
--- a/MdePkg/Library/BaseLib/X64/GccInline.c
+++ b/MdePkg/Library/BaseLib/X64/GccInline.c
@@ -1798,3 +1798,33 @@ AsmFlushCacheLine (
}
+/**
+ Executes a XGETBV instruction
+
+ Executes a XGETBV instruction. This function is only available on IA-32 and
+ x64.
+
+ @param[in] Index Extended control register index
+
+ @return The current value of the extended control register
+**/
+UINT64
+EFIAPI
+AsmXGetBv (
+ IN UINT32 Index
+ )
+{
+ UINT32 LowData;
+ UINT32 HighData;
+
+ __asm__ __volatile__ (
+ "xgetbv"
+ : "=a" (LowData),
+ "=d" (HighData)
+ : "c" (Index)
+ );
+
+ return (((UINT64)HighData) << 32) | LowData;
+}
+
+
diff --git a/MdePkg/Library/BaseLib/Ia32/XGetBv.nasm
b/MdePkg/Library/BaseLib/Ia32/XGetBv.nasm
new file mode 100644
index 000000000000..9f7b03bbff35
--- /dev/null
+++ b/MdePkg/Library/BaseLib/Ia32/XGetBv.nasm
@@ -0,0 +1,31 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
+; SPDX-License-Identifier: BSD-2-Clause-Patent
+;
+; Module Name:
+;
+; XGetBv.Asm
+;
+; Abstract:
+;
+; AsmXgetBv function
+;
+; Notes:
+;
+;------------------------------------------------------------------------------
+
+ SECTION .text
+
+;------------------------------------------------------------------------------
+; UINT64
+; EFIAPI
+; AsmXGetBv (
+; IN UINT32 Index
+; );
+;------------------------------------------------------------------------------
+global ASM_PFX(AsmXGetBv)
+ASM_PFX(AsmXGetBv):
+ mov ecx, [esp + 4]
+ xgetbv
+ ret
diff --git a/MdePkg/Library/BaseLib/X64/XGetBv.nasm
b/MdePkg/Library/BaseLib/X64/XGetBv.nasm
new file mode 100644
index 000000000000..09f3be8ae0a8
--- /dev/null
+++ b/MdePkg/Library/BaseLib/X64/XGetBv.nasm
@@ -0,0 +1,34 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
+; SPDX-License-Identifier: BSD-2-Clause-Patent
+;
+; Module Name:
+;
+; XGetBv.Asm
+;
+; Abstract:
+;
+; AsmXgetBv function
+;
+; Notes:
+;
+;------------------------------------------------------------------------------
+
+ DEFAULT REL
+ SECTION .text
+
+;------------------------------------------------------------------------------
+; UINT64
+; EFIAPI
+; AsmXGetBv (
+; IN UINT32 Index
+; );
+;------------------------------------------------------------------------------
+global ASM_PFX(AsmXGetBv)
+ASM_PFX(AsmXGetBv):
+ xgetbv
+ shl rdx, 32
+ or rax, rdx
+ ret
+
--
2.27.0
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