From: Kirill A. Shutemov Date: Wed, 24 Apr 2024 08:20:35 +0000 (+0300) Subject: x86/tdx: Preserve shared bit on mprotect() X-Git-Tag: v6.9-rc6~2^2~2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a0a8d15a798be4b8f20aca2ba91bf6b688c6a640;p=thirdparty%2Fkernel%2Flinux.git x86/tdx: Preserve shared bit on mprotect() The TDX guest platform takes one bit from the physical address to indicate if the page is shared (accessible by VMM). This bit is not part of the physical_mask and is not preserved during mprotect(). As a result, the 'shared' bit is lost during mprotect() on shared mappings. _COMMON_PAGE_CHG_MASK specifies which PTE bits need to be preserved during modification. AMD includes 'sme_me_mask' in the define to preserve the 'encrypt' bit. To cover both Intel and AMD cases, include 'cc_mask' in _COMMON_PAGE_CHG_MASK instead of 'sme_me_mask'. Reported-and-tested-by: Chris Oo Fixes: 41394e33f3a0 ("x86/tdx: Extend the confidential computing API to support TDX guests") Signed-off-by: Kirill A. Shutemov Signed-off-by: Dave Hansen Reviewed-by: Rick Edgecombe Reviewed-by: Kuppuswamy Sathyanarayanan Reviewed-by: Tom Lendacky Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20240424082035.4092071-1-kirill.shutemov%40linux.intel.com --- diff --git a/arch/x86/include/asm/coco.h b/arch/x86/include/asm/coco.h index c086699b0d0c5..aa6c8f8ca9588 100644 --- a/arch/x86/include/asm/coco.h +++ b/arch/x86/include/asm/coco.h @@ -25,6 +25,7 @@ u64 cc_mkdec(u64 val); void cc_random_init(void); #else #define cc_vendor (CC_VENDOR_NONE) +static const u64 cc_mask = 0; static inline u64 cc_mkenc(u64 val) { diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 0b748ee16b3d9..9abb8cc4cd474 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -148,7 +148,7 @@ #define _COMMON_PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \ _PAGE_SPECIAL | _PAGE_ACCESSED | \ _PAGE_DIRTY_BITS | _PAGE_SOFT_DIRTY | \ - _PAGE_DEVMAP | _PAGE_ENC | _PAGE_UFFD_WP) + _PAGE_DEVMAP | _PAGE_CC | _PAGE_UFFD_WP) #define _PAGE_CHG_MASK (_COMMON_PAGE_CHG_MASK | _PAGE_PAT) #define _HPAGE_CHG_MASK (_COMMON_PAGE_CHG_MASK | _PAGE_PSE | _PAGE_PAT_LARGE) @@ -173,6 +173,7 @@ enum page_cache_mode { }; #endif +#define _PAGE_CC (_AT(pteval_t, cc_mask)) #define _PAGE_ENC (_AT(pteval_t, sme_me_mask)) #define _PAGE_CACHE_MASK (_PAGE_PWT | _PAGE_PCD | _PAGE_PAT)