The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: a0a8d15a798be4b8f20aca2ba91bf6b688c6a640 Gitweb: https://git.kernel.org/tip/a0a8d15a798be4b8f20aca2ba91bf6b688c6a640 Author: Kirill A. Shutemov kirill.shutemov@linux.intel.com AuthorDate: Wed, 24 Apr 2024 11:20:35 +03:00 Committer: Dave Hansen dave.hansen@linux.intel.com CommitterDate: Wed, 24 Apr 2024 08:11:43 -07:00

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 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... --- arch/x86/include/asm/coco.h | 1 + arch/x86/include/asm/pgtable_types.h | 3 ++- 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/coco.h b/arch/x86/include/asm/coco.h index c086699..aa6c8f8 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 0b748ee..9abb8cc 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)