回复: [edk2-devel] [RFC PATCH 09/19] MdePkg: Add AsmPvalidate() support

["gaoliming" <gaoliming@byosoft.com.cn>]

Is this API X64 only? Or IA32 and X64 both?

Thanks
Liming
> -----邮件原件-----
> 发件人: devel@edk2.groups.io <devel@edk2.groups.io> 代表 Brijesh Singh
> 发送时间: 2021年3月24日 23:32
> 收件人: devel@edk2.groups.io
> 抄送: Brijesh Singh <brijesh.singh@amd.com>; James Bottomley
> <jejb@linux.ibm.com>; Min Xu <min.m.xu@intel.com>; Jiewen Yao
> <jiewen.yao@intel.com>; Tom Lendacky <thomas.lendacky@amd.com>;
> Jordan Justen <jordan.l.justen@intel.com>; Ard Biesheuvel
> <ardb+tianocore@kernel.org>; Laszlo Ersek <lersek@redhat.com>
> 主题: [edk2-devel] [RFC PATCH 09/19] MdePkg: Add AsmPvalidate() support
> 
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275
> 
> The PVALIDATE instruction validates or rescinds validation of a guest
> page RMP entry. Upon completion, a return code is stored in EAX, rFLAGS
> bits OF, ZF, AF, PF and SF are set based on this return code. If the
> instruction completed succesfully, the rFLAGS bit CF indicates if the
> contents of the RMP entry were changed or not.
> 
> For more information about the instruction see AMD APM volume 3.
> 
> Cc: James Bottomley <jejb@linux.ibm.com>
> Cc: Min Xu <min.m.xu@intel.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Tom Lendacky <thomas.lendacky@amd.com>
> Cc: Jordan Justen <jordan.l.justen@intel.com>
> Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
>  MdePkg/Include/Library/BaseLib.h          | 37 +++++++++++++++++
>  MdePkg/Library/BaseLib/BaseLib.inf        |  1 +
>  MdePkg/Library/BaseLib/X64/Pvalidate.nasm | 43 ++++++++++++++++++++
>  3 files changed, 81 insertions(+)
> 
> diff --git a/MdePkg/Include/Library/BaseLib.h
> b/MdePkg/Include/Library/BaseLib.h
> index 1171a0ffb5..fee27e9a1b 100644
> --- a/MdePkg/Include/Library/BaseLib.h
> +++ b/MdePkg/Include/Library/BaseLib.h
> @@ -7495,5 +7495,42 @@ PatchInstructionX86 (
>    IN  UINTN                    ValueSize
>    );
> 
> +/**
> + Execute a PVALIDATE instruction to validate or rescnids validation of a
guest
> + page's RMP entry.
> +
> + Upon completion, in addition to the return value the instruction also
> updates
> + the eFlags. A caller must check both the return code as well as eFlags
to
> + determine if the RMP entry has been updated.
> +
> + The function is available on x64.
> +
> + @param[in]    Address        The guest virtual address to validate.
> + @param[in]    PageSize       The page size to use.
> + @param[i]     Validate       Validate or rescinds.
> + @param[out]   Eflags         The value of Eflags after PVALIDATE
> completion.
> +
> + @retval       PvalidateRetValue  The return value from the PVALIDATE
> instruction.
> +**/
> +typedef enum {
> +  PVALIDATE_PAGE_SIZE_4K = 0,
> +  PVALIDATE_PAGE_SIZE_2M,
> +} PvalidatePageSize;
> +
> +typedef enum {
> +  PVALIDATE_RET_SUCCESS = 0,
> +  PVALIDATE_RET_FAIL_INPUT = 1,
> +  PVALIDATE_RET_FAIL_SIZEMISMATCH = 6,
> +} PvalidateRetValue;
> +
> +PvalidateRetValue
> +EFIAPI
> +AsmPvalidate (
> +  IN   PvalidatePageSize       PageSize,
> +  IN   BOOLEAN                 Validate,
> +  IN   UINTN                   Address,
> +  OUT  IA32_EFLAGS32           *Eflags
> +  );
> +
>  #endif // defined (MDE_CPU_IA32) || defined (MDE_CPU_X64)
>  #endif // !defined (__BASE_LIB__)
> diff --git a/MdePkg/Library/BaseLib/BaseLib.inf
> b/MdePkg/Library/BaseLib/BaseLib.inf
> index 3b85c56c3c..01aa5cc7a4 100644
> --- a/MdePkg/Library/BaseLib/BaseLib.inf
> +++ b/MdePkg/Library/BaseLib/BaseLib.inf
> @@ -319,6 +319,7 @@
>    X64/RdRand.nasm
>    X64/XGetBv.nasm
>    X64/VmgExit.nasm
> +  X64/Pvalidate.nasm
>    ChkStkGcc.c  | GCC
> 
>  [Sources.EBC]
> diff --git a/MdePkg/Library/BaseLib/X64/Pvalidate.nasm
> b/MdePkg/Library/BaseLib/X64/Pvalidate.nasm
> new file mode 100644
> index 0000000000..f2aba114ac
> --- /dev/null
> +++ b/MdePkg/Library/BaseLib/X64/Pvalidate.nasm
> @@ -0,0 +1,43 @@
>
+;--------------------------------------------------------------------------
---
> +;
> +; Copyright (c) 2020-2021, AMD. All rights reserved.<BR>
> +; SPDX-License-Identifier: BSD-2-Clause-Patent
> +;
> +; Module Name:
> +;
> +;   Pvalidate.Asm
> +;
> +; Abstract:
> +;
> +;   AsmPvalidate function
> +;
> +; Notes:
> +;
>
+;--------------------------------------------------------------------------
---
> +
> +    SECTION .text
> +
>
+;--------------------------------------------------------------------------
---
> +;  PvalidateRetValue
> +;  EFIAPI
> +;  AsmPvalidate (
> +;    IN   UINT32  RmpPageSize
> +;    IN   UINT32  Validate,
> +;    IN   UINTN   Address,
> +;    OUT  UINTN  *Eflags,
> +;    )
>
+;--------------------------------------------------------------------------
---
> +global ASM_PFX(AsmPvalidate)
> +ASM_PFX(AsmPvalidate):
> +  mov     rax, r8
> +
> +  ; PVALIDATE instruction opcode
> +  DB      0xF2, 0x0F, 0x01, 0xFF
> +
> +  ; Read the Eflags
> +  pushfq
> +  pop     r8
> +  mov     [r9], r8
> +
> +  ; The PVALIDATE instruction returns the status in rax register.
> +  ret
> --
> 2.17.1
> 
> 
> 
> 
>