Re: [edk2-devel] [PATCH v10 06/46] MdePkg/BaseLib: Add support for the XGETBV instruction

["Laszlo Ersek" <lersek@redhat.com>]

Hi Tom,

On 07/14/20 16:27, Lendacky, Thomas wrote:
> From: Tom Lendacky <thomas.lendacky@amd.com>
> 
> 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.kinney@intel.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Signed-off-by: Tom Lendacky <thomas.lendacky@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(+)
>  create mode 100644 MdePkg/Library/BaseLib/Ia32/XGetBv.nasm
>  create mode 100644 MdePkg/Library/BaseLib/X64/XGetBv.nasm

This patch no longer applies, it conflicts with commit d3c9e40abcc8
("MdePkg/BaseLib: Break out IA32/X64 GCC inline privileged functions",
2020-07-15).

The conflict persists if I successfully apply the series on c7195b9ec3c5
-- just preceding Mike's series "[Patch v3 00/16] UnitTestFrameworkPkg:
Enhancements and bug fixes" --, and then try to rebase to current master
(e77966b341b9) from there.

Can you please investigate?

Thanks,
Laszlo

> 
> 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
> +
>