From 5a7cbd54a161dd135381d753758269189200013c Mon Sep 17 00:00:00 2001 From: Brijesh Singh Date: Wed, 19 May 2021 13:19:43 -0500 Subject: [PATCH] MdePkg/BaseLib: add support for PVALIDATE instruction 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 Cc: Min Xu Cc: Jiewen Yao Cc: Tom Lendacky Cc: Jordan Justen Cc: Ard Biesheuvel Cc: Laszlo Ersek Cc: Erdem Aktas Cc: Michael D Kinney Cc: Liming Gao Cc: Zhiguang Liu Reviewed-by: Liming Gao Reviewed-by: Laszlo Ersek Signed-off-by: Brijesh Singh Message-Id: <20210519181949.6574-8-brijesh.singh@amd.com> --- MdePkg/Include/Library/BaseLib.h | 50 +++++++++++++++++++++++ MdePkg/Include/X64/Nasm.inc | 8 ++++ MdePkg/Library/BaseLib/BaseLib.inf | 1 + MdePkg/Library/BaseLib/X64/Pvalidate.nasm | 42 +++++++++++++++++++ 4 files changed, 101 insertions(+) create mode 100644 MdePkg/Library/BaseLib/X64/Pvalidate.nasm diff --git a/MdePkg/Include/Library/BaseLib.h b/MdePkg/Include/Library/BaseLib.h index 7253997a6f..a2cd134bea 100644 --- a/MdePkg/Include/Library/BaseLib.h +++ b/MdePkg/Include/Library/BaseLib.h @@ -4813,6 +4813,56 @@ SpeculationBarrier ( VOID ); +#if defined (MDE_CPU_X64) +// +// The page size for the PVALIDATE instruction +// +typedef enum { + PvalidatePageSize4K = 0, + PvalidatePageSize2MB, +} PVALIDATE_PAGE_SIZE; + +// +// PVALIDATE Return Code. +// +#define PVALIDATE_RET_SUCCESS 0 +#define PVALIDATE_RET_FAIL_INPUT 1 +#define PVALIDATE_RET_SIZE_MISMATCH 6 + +// +// The PVALIDATE instruction did not make any changes to the RMP entry. +// +#define PVALIDATE_RET_NO_RMPUPDATE 255 + +/** + Execute a PVALIDATE instruction to validate or to rescinds validation of a guest + page's RMP entry. + + The instruction is available only when CPUID Fn8000_001F_EAX[SNP]=1. + + The function is available on X64. + + @param[in] PageSize The page size to use. + @param[in] Validate If TRUE, validate the guest virtual address + otherwise invalidate the guest virtual address. + @param[in] Address The guest virtual address. + + @retval PVALIDATE_RET_SUCCESS The PVALIDATE instruction succeeded, and + updated the RMP entry. + @retval PVALIDATE_RET_NO_RMPUPDATE The PVALIDATE instruction succeeded, but + did not update the RMP entry. + @return Failure code from the PVALIDATE + instruction. +**/ +UINT32 +EFIAPI +AsmPvalidate ( + IN PVALIDATE_PAGE_SIZE PageSize, + IN BOOLEAN Validate, + IN PHYSICAL_ADDRESS Address + ); +#endif + #if defined (MDE_CPU_IA32) || defined (MDE_CPU_X64) /// diff --git a/MdePkg/Include/X64/Nasm.inc b/MdePkg/Include/X64/Nasm.inc index 527f71e9eb..528bb33856 100644 --- a/MdePkg/Include/X64/Nasm.inc +++ b/MdePkg/Include/X64/Nasm.inc @@ -33,6 +33,14 @@ DB 0xF3, 0x48, 0x0F, 0xAE, 0xE8 %endmacro +; +; Macro for the PVALIDATE instruction, defined in AMD APM volume 3. +; NASM feature request URL: https://bugzilla.nasm.us/show_bug.cgi?id=3392753 +; +%macro PVALIDATE 0 + DB 0xF2, 0x0F, 0x01, 0xFF +%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/BaseLib.inf b/MdePkg/Library/BaseLib/BaseLib.inf index b76f3af380..89a52f72c0 100644 --- a/MdePkg/Library/BaseLib/BaseLib.inf +++ b/MdePkg/Library/BaseLib/BaseLib.inf @@ -317,6 +317,7 @@ X64/GccInlinePriv.c | GCC X64/EnableDisableInterrupts.nasm X64/DisablePaging64.nasm + X64/Pvalidate.nasm X64/RdRand.nasm X64/XGetBv.nasm X64/XSetBv.nasm diff --git a/MdePkg/Library/BaseLib/X64/Pvalidate.nasm b/MdePkg/Library/BaseLib/X64/Pvalidate.nasm new file mode 100644 index 0000000000..a7d1779134 --- /dev/null +++ b/MdePkg/Library/BaseLib/X64/Pvalidate.nasm @@ -0,0 +1,42 @@ +;----------------------------------------------------------------------------- +; +; Copyright (c) 2021, AMD. All rights reserved.
+; SPDX-License-Identifier: BSD-2-Clause-Patent +; +;----------------------------------------------------------------------------- + +%include "Nasm.inc" + + SECTION .text + +;----------------------------------------------------------------------------- +; UINT32 +; EFIAPI +; AsmPvalidate ( +; IN UINT32 PageSize +; IN UINT32 Validate, +; IN UINT64 Address +; ) +;----------------------------------------------------------------------------- +global ASM_PFX(AsmPvalidate) +ASM_PFX(AsmPvalidate): + mov rax, r8 + + PVALIDATE + + ; Save the carry flag. + setc dl + + ; The PVALIDATE instruction returns the status in rax register. + cmp rax, 0 + jne PvalidateExit + + ; Check the carry flag to determine if RMP entry was updated. + cmp dl, 0 + je PvalidateExit + + ; Return the PVALIDATE_RET_NO_RMPUPDATE. + mov rax, 255 + +PvalidateExit: + ret -- 2.39.2