[edk2-devel] [PATCH v2 08/13] MdePkg/BaseLib: add support for RMPADJUST instruction
Laszlo Ersek
lersek at redhat.com
Mon May 17 03:25:50 UTC 2021
On 05/13/21 01:46, Brijesh Singh wrote:
> From: Tom Lendacky <thomas.lendacky at amd.com>
>
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275
>
> The RMPADJUST instruction will be used by the SEV-SNP guest to modify the
> RMP permissions for a guest page. See AMD APM volume 3 for further
> details.
>
> Cc: James Bottomley <jejb at linux.ibm.com>
> Cc: Min Xu <min.m.xu at intel.com>
> Cc: Jiewen Yao <jiewen.yao at intel.com>
> Cc: Tom Lendacky <thomas.lendacky at amd.com>
> Cc: Jordan Justen <jordan.l.justen at intel.com>
> Cc: Ard Biesheuvel <ardb+tianocore at kernel.org>
> Cc: Laszlo Ersek <lersek at redhat.com>
> Cc: Erdem Aktas <erdemaktas at google.com>
> Cc: Michael D Kinney <michael.d.kinney at intel.com>
> Cc: Liming Gao <gaoliming at byosoft.com.cn>
> Cc: Zhiguang Liu <zhiguang.liu at intel.com>
> Reviewed-by: Laszlo Ersek <lersek at redhat.com>
> Reviewed-by: Liming Gao <gaoliming at byosoft.com.cn>
> Signed-off-by: Tom Lendacky <thomas.lendacky at amd.com>
> Signed-off-by: Brijesh Singh <brijesh.singh at amd.com>
> ---
> MdePkg/Library/BaseLib/BaseLib.inf | 1 +
> MdePkg/Include/Library/BaseLib.h | 35 ++++++++++++++++++++
> MdePkg/Include/X64/Nasm.inc | 8 +++++
> MdePkg/Library/BaseLib/X64/RmpAdjust.nasm | 40 +++++++++++++++++++++++
> 4 files changed, 84 insertions(+)
> create mode 100644 MdePkg/Library/BaseLib/X64/RmpAdjust.nasm
>
> diff --git a/MdePkg/Library/BaseLib/BaseLib.inf b/MdePkg/Library/BaseLib/BaseLib.inf
> index 89a52f72c08a..6ccb8997b7e8 100644
> --- a/MdePkg/Library/BaseLib/BaseLib.inf
> +++ b/MdePkg/Library/BaseLib/BaseLib.inf
> @@ -319,6 +319,7 @@ [Sources.X64]
> X64/DisablePaging64.nasm
> X64/Pvalidate.nasm
> X64/RdRand.nasm
> + X64/RmpAdjust.nasm
> X64/XGetBv.nasm
> X64/XSetBv.nasm
> X64/VmgExit.nasm
> diff --git a/MdePkg/Include/Library/BaseLib.h b/MdePkg/Include/Library/BaseLib.h
> index a2cd134bea9a..e8eff32716b8 100644
> --- a/MdePkg/Include/Library/BaseLib.h
> +++ b/MdePkg/Include/Library/BaseLib.h
> @@ -4861,6 +4861,41 @@ AsmPvalidate (
> IN BOOLEAN Validate,
> IN PHYSICAL_ADDRESS Address
> );
> +
> +//
> +// RDX settings for RMPADJUST
> +//
> +#define RMPADJUST_VMPL_MAX 3
> +#define RMPADJUST_VMPL_MASK 0xFF
> +#define RMPADJUST_VMPL_SHIFT 0
> +#define RMPADJUST_PERMISSION_MASK_MASK 0xFF
> +#define RMPADJUST_PERMISSION_MASK_SHIFT 8
> +#define RMPADJUST_VMSA_PAGE_BIT BIT16
> +
> +/**
> + Adjusts the permissions of an SEV-SNP guest page.
> +
> + Executes a RMPADJUST instruction with the register state specified by Rax,
> + Rcx, and Rdx. Returns Rax. This function is only available on X64.
> +
> + The instruction is available only when CPUID Fn8000_001F_EAX[SNP]=1.
> +
> + @param[in] Rax The value to load into RAX before executing the RMPADJUST
> + instruction.
> + @param[in] Rcx The value to load into RCX before executing the RMPADJUST
> + instruction.
> + @param[in] Rdx The value to load into RDX before executing the RMPADJUST
> + instruction.
> +
> + @return Rax
> +**/
> +UINT32
> +EFIAPI
> +AsmRmpAdjust (
> + IN UINT64 Rax,
> + IN UINT64 Rcx,
> + IN UINT64 Rdx
> + );
> #endif
(1) Relative to v1, the updates are all good (thanks!), except for one:
"@return Rax" is actually a regression -- "@return Eax" was correct, in
my opinion.
This also affects the top of the leading comment, where Eax was also
replaced with Rax.
My R-b stands, but please fix the docs on this function again, because
now the documentation ("Rax", twice) is actually inconsistent with the
return type UINT32.
Thanks
Laszlo
>
>
> diff --git a/MdePkg/Include/X64/Nasm.inc b/MdePkg/Include/X64/Nasm.inc
> index 528bb3385609..cfb14edc9449 100644
> --- a/MdePkg/Include/X64/Nasm.inc
> +++ b/MdePkg/Include/X64/Nasm.inc
> @@ -41,6 +41,14 @@
> DB 0xF2, 0x0F, 0x01, 0xFF
> %endmacro
>
> +;
> +; Macro for the RMPADJUST instruction, defined in AMD APM volume 3.
> +; NASM feature request URL: https://bugzilla.nasm.us/show_bug.cgi?id=3392754
> +;
> +%macro RMPADJUST 0
> + DB 0xF3, 0x0F, 0x01, 0xFE
> +%endmacro
> +
> ; NASM provides built-in macros STRUC and ENDSTRUC for structure definition.
> ; For example, to define a structure called mytype containing a longword,
> ; a word, a byte and a string of bytes, you might code
> diff --git a/MdePkg/Library/BaseLib/X64/RmpAdjust.nasm b/MdePkg/Library/BaseLib/X64/RmpAdjust.nasm
> new file mode 100644
> index 000000000000..c307f64b518a
> --- /dev/null
> +++ b/MdePkg/Library/BaseLib/X64/RmpAdjust.nasm
> @@ -0,0 +1,40 @@
> +;-----------------------------------------------------------------------------
> +;
> +; Copyright (c) 2021, Advanced Micro Devices, Inc. All rights reserved.<BR>
> +; SPDX-License-Identifier: BSD-2-Clause-Patent
> +;
> +; Module Name:
> +;
> +; RmpAdjust.Asm
> +;
> +; Abstract:
> +;
> +; AsmRmpAdjust function
> +;
> +; Notes:
> +;
> +;-----------------------------------------------------------------------------
> +
> +%include "Nasm.inc"
> +
> + SECTION .text
> +
> +;-----------------------------------------------------------------------------
> +; UINT32
> +; EFIAPI
> +; AsmRmpAdjust (
> +; IN UINT64 Rax,
> +; IN UINT64 Rcx,
> +; IN UINT64 Rdx
> +; )
> +;-----------------------------------------------------------------------------
> +global ASM_PFX(AsmRmpAdjust)
> +ASM_PFX(AsmRmpAdjust):
> + mov rax, rcx ; Input Rax is in RCX by calling convention
> + mov rcx, rdx ; Input Rcx is in RDX by calling convention
> + mov rdx, r8 ; Input Rdx is in R8 by calling convention
> +
> + RMPADJUST
> +
> + ; RMPADJUST returns the status in the EAX register.
> + ret
>
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