From b577f542f93cbba57f8d6185ef1fb13a41ddf162 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Tue, 22 Feb 2022 21:57:40 +0300 Subject: [PATCH] x86/coco: Add API to handle encryption mask AMD SME/SEV uses a bit in the page table entries to indicate that the page is encrypted and not accessible to the VMM. TDX uses a similar approach, but the polarity of the mask is opposite to AMD: if the bit is set the page is accessible to VMM. Provide vendor-neutral API to deal with the mask: cc_mkenc() and cc_mkdec() modify given address to make it encrypted/decrypted. It can be applied to phys_addr_t, pgprotval_t or page table entry value. pgprot_encrypted() and pgprot_decrypted() reimplemented using new helpers. The implementation will be extended to cover TDX. pgprot_decrypted() is used by drivers (i915, virtio_gpu, vfio). cc_mkdec() called by pgprot_decrypted(). Export cc_mkdec(). Signed-off-by: Kirill A. Shutemov Signed-off-by: Borislav Petkov Reviewed-by: Tom Lendacky Link: https://lore.kernel.org/r/20220222185740.26228-5-kirill.shutemov@linux.intel.com --- arch/x86/coco/core.c | 27 +++++++++++++++++++++++++++ arch/x86/include/asm/coco.h | 18 ++++++++++++++++++ arch/x86/include/asm/pgtable.h | 13 +++++++------ arch/x86/mm/mem_encrypt_identity.c | 1 + arch/x86/mm/pat/set_memory.c | 5 +++-- 5 files changed, 56 insertions(+), 8 deletions(-) diff --git a/arch/x86/coco/core.c b/arch/x86/coco/core.c index 476dcd198af5..fc1365dd927e 100644 --- a/arch/x86/coco/core.c +++ b/arch/x86/coco/core.c @@ -14,6 +14,7 @@ #include static enum cc_vendor vendor __ro_after_init; +static u64 cc_mask __ro_after_init; static bool intel_cc_platform_has(enum cc_attr attr) { @@ -84,7 +85,33 @@ bool cc_platform_has(enum cc_attr attr) } EXPORT_SYMBOL_GPL(cc_platform_has); +u64 cc_mkenc(u64 val) +{ + switch (vendor) { + case CC_VENDOR_AMD: + return val | cc_mask; + default: + return val; + } +} + +u64 cc_mkdec(u64 val) +{ + switch (vendor) { + case CC_VENDOR_AMD: + return val & ~cc_mask; + default: + return val; + } +} +EXPORT_SYMBOL_GPL(cc_mkdec); + __init void cc_set_vendor(enum cc_vendor v) { vendor = v; } + +__init void cc_set_mask(u64 mask) +{ + cc_mask = mask; +} diff --git a/arch/x86/include/asm/coco.h b/arch/x86/include/asm/coco.h index e49f9ddb6ae6..3d98c3a60d34 100644 --- a/arch/x86/include/asm/coco.h +++ b/arch/x86/include/asm/coco.h @@ -2,6 +2,8 @@ #ifndef _ASM_X86_COCO_H #define _ASM_X86_COCO_H +#include + enum cc_vendor { CC_VENDOR_NONE, CC_VENDOR_AMD, @@ -10,5 +12,21 @@ enum cc_vendor { }; void cc_set_vendor(enum cc_vendor v); +void cc_set_mask(u64 mask); + +#ifdef CONFIG_ARCH_HAS_CC_PLATFORM +u64 cc_mkenc(u64 val); +u64 cc_mkdec(u64 val); +#else +static inline u64 cc_mkenc(u64 val) +{ + return val; +} + +static inline u64 cc_mkdec(u64 val) +{ + return val; +} +#endif #endif /* _ASM_X86_COCO_H */ diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 8a9432fb3802..62ab07e24aef 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -15,17 +15,12 @@ cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS))) \ : (prot)) -/* - * Macros to add or remove encryption attribute - */ -#define pgprot_encrypted(prot) __pgprot(__sme_set(pgprot_val(prot))) -#define pgprot_decrypted(prot) __pgprot(__sme_clr(pgprot_val(prot))) - #ifndef __ASSEMBLY__ #include #include #include #include +#include #include #include @@ -38,6 +33,12 @@ void ptdump_walk_pgd_level_debugfs(struct seq_file *m, struct mm_struct *mm, void ptdump_walk_pgd_level_checkwx(void); void ptdump_walk_user_pgd_level_checkwx(void); +/* + * Macros to add or remove encryption attribute + */ +#define pgprot_encrypted(prot) __pgprot(cc_mkenc(pgprot_val(prot))) +#define pgprot_decrypted(prot) __pgprot(cc_mkdec(pgprot_val(prot))) + #ifdef CONFIG_DEBUG_WX #define debug_checkwx() ptdump_walk_pgd_level_checkwx() #define debug_checkwx_user() ptdump_walk_user_pgd_level_checkwx() diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c index 06314ae3998e..b43bc24d2bb6 100644 --- a/arch/x86/mm/mem_encrypt_identity.c +++ b/arch/x86/mm/mem_encrypt_identity.c @@ -604,5 +604,6 @@ out: if (sme_me_mask) { physical_mask &= ~sme_me_mask; cc_set_vendor(CC_VENDOR_AMD); + cc_set_mask(sme_me_mask); } } diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c index b4072115c8ef..1441db69cea5 100644 --- a/arch/x86/mm/pat/set_memory.c +++ b/arch/x86/mm/pat/set_memory.c @@ -1989,6 +1989,7 @@ int set_memory_global(unsigned long addr, int numpages) */ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc) { + pgprot_t empty = __pgprot(0); struct cpa_data cpa; int ret; @@ -1999,8 +2000,8 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc) memset(&cpa, 0, sizeof(cpa)); cpa.vaddr = &addr; cpa.numpages = numpages; - cpa.mask_set = enc ? __pgprot(_PAGE_ENC) : __pgprot(0); - cpa.mask_clr = enc ? __pgprot(0) : __pgprot(_PAGE_ENC); + cpa.mask_set = enc ? pgprot_encrypted(empty) : pgprot_decrypted(empty); + cpa.mask_clr = enc ? pgprot_decrypted(empty) : pgprot_encrypted(empty); cpa.pgd = init_mm.pgd; /* Must avoid aliasing mappings in the highmem code */