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 cho@microsoft.com
Fixes: 41394e33f3a0 ("x86/tdx: Extend the confidential computing API to support TDX guests") Signed-off-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Signed-off-by: Dave Hansen dave.hansen@linux.intel.com Reviewed-by: Rick Edgecombe rick.p.edgecombe@intel.com Reviewed-by: Kuppuswamy Sathyanarayanan sathyanarayanan.kuppuswamy@linux.intel.com Reviewed-by: Tom Lendacky thomas.lendacky@amd.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20240424082035.4092071-1-kirill.shutemov%40linux... (cherry picked from commit a0a8d15a798be4b8f20aca2ba91bf6b688c6a640) Signed-off-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com --- arch/x86/include/asm/coco.h | 5 ++++- arch/x86/include/asm/pgtable_types.h | 3 ++- 2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/coco.h b/arch/x86/include/asm/coco.h index 1f97d00ad858..100a752c33bb 100644 --- a/arch/x86/include/asm/coco.h +++ b/arch/x86/include/asm/coco.h @@ -13,9 +13,10 @@ enum cc_vendor { };
extern enum cc_vendor cc_vendor; -extern u64 cc_mask;
#ifdef CONFIG_ARCH_HAS_CC_PLATFORM +extern u64 cc_mask; + static inline void cc_set_mask(u64 mask) { RIP_REL_REF(cc_mask) = mask; @@ -25,6 +26,8 @@ u64 cc_mkenc(u64 val); u64 cc_mkdec(u64 val); void cc_random_init(void); #else +static const u64 cc_mask = 0; + static inline u64 cc_mkenc(u64 val) { return val; diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index f6116b66f289..f0b9b37c4609 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -127,7 +127,7 @@ */ #define _COMMON_PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \ _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY |\ - _PAGE_SOFT_DIRTY | _PAGE_DEVMAP | _PAGE_ENC | \ + _PAGE_SOFT_DIRTY | _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) @@ -153,6 +153,7 @@ 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)