Messages in this thread Patch in this message | | | Date | Tue, 22 Feb 2022 14:03:12 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCHv3 02/32] x86/coco: Add API to handle encryption mask |
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On Tue, Feb 22, 2022 at 01:28:56AM +0300, Kirill A. Shutemov wrote: > On Mon, Feb 21, 2022 at 11:28:16AM -0800, Dave Hansen wrote: > > I'm just a bit confused why *this* was chosen as the cc_whatever() hook. > > Just like the mask function, it has one spot where it gets used: > > > > +#define pgprot_encrypted(prot) __pgprot(cc_mkenc(pgprot_val(prot))) > > +#define pgprot_decrypted(prot) __pgprot(cc_mkdec(pgprot_val(prot))) > > > > So, why bother having another level of abstraction? > > > > Why don't we just have: > > > > pgprot_t cc_mkenc(pgprot prot) > > pgprot_t cc_mkenc(pgprot prot) > > > > and *no* pgprot_{en,de}crypted()? > > Okay. Let me try this.
Below it how it would look like.
I don't like it, especially, tdx_enc_status_changed() case. There are more cases like this in attestation code.
I would rather make cc_mkenc()/cc_mkdec() to operate on u64 (or phys_addr_t?) while pgprot_encrypted()/pgprot_decrypted() cover pgprot_t. It also makes set_memory cleaner:
cpa.mask_set = __pgprot(enc ? cc_mkenc(0) : cc_mkdec(0)); cpa.mask_clr = __pgprot(enc ? cc_mkdec(0) : cc_mkenc(0));
Opinions?
diff --git a/arch/x86/coco/tdx.c b/arch/x86/coco/tdx.c index fb32c271fe34..bf5ba7d5b736 100644 --- a/arch/x86/coco/tdx.c +++ b/arch/x86/coco/tdx.c @@ -514,8 +514,8 @@ static int tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc) return -EINVAL; if (!enc) { - start = cc_mkenc(start); - end = cc_mkenc(end); + start |= pgprot_val(cc_mkenc(__pgprot(0))); + end |= pgprot_val(cc_mkenc(__pgprot(0))); } /* diff --git a/arch/x86/include/asm/coco.h b/arch/x86/include/asm/coco.h index 802d87d08e31..fba1dd2ef319 100644 --- a/arch/x86/include/asm/coco.h +++ b/arch/x86/include/asm/coco.h @@ -14,13 +14,18 @@ enum cc_vendor { void cc_init(enum cc_vendor, u64 mask); #ifdef CONFIG_ARCH_HAS_CC_PLATFORM -u64 cc_get_mask(bool enc); -u64 cc_mkenc(u64 val); -u64 cc_mkdec(u64 val); +pgprot_t cc_mkenc(pgprot_t prot); +pgprot_t cc_mkdec(pgprot_t prot); #else -#define cc_get_mask(enc) 0 -#define cc_mkenc(val) (val) -#define cc_mkdec(val) (val) +static inline pgprot_t cc_mkenc(pgprot_t prot) +{ + return prot; +} + +static inline pgprot_t cc_mkdec(pgprot_t prot) +{ + return prot; +} #endif #endif /* _ASM_X86_COCO_H */ diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 62ab07e24aef..8cba0d258e49 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -36,8 +36,8 @@ 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))) +#define pgprot_encrypted(prot) cc_mkenc(prot) +#define pgprot_decrypted(prot) cc_mkdec(prot) #ifdef CONFIG_DEBUG_WX #define debug_checkwx() ptdump_walk_pgd_level_checkwx() diff --git a/arch/x86/kernel/cc_platform.c b/arch/x86/kernel/cc_platform.c index 12a34e80ef50..d13a034e9a21 100644 --- a/arch/x86/kernel/cc_platform.c +++ b/arch/x86/kernel/cc_platform.c @@ -12,6 +12,7 @@ #include <asm/coco.h> #include <asm/processor.h> +#include <asm/pgtable_types.h> static u64 cc_mask; static enum cc_vendor cc_vendor; @@ -93,39 +94,27 @@ bool cc_platform_has(enum cc_attr attr) } EXPORT_SYMBOL_GPL(cc_platform_has); -u64 cc_get_mask(bool enc) +pgprot_t cc_mkenc(pgprot_t prot) { switch (cc_vendor) { case CC_VENDOR_AMD: - return enc ? cc_mask : 0; + return __pgprot(pgprot_val(prot) | cc_mask); case CC_VENDOR_INTEL: - return enc ? 0 : cc_mask; + return __pgprot(pgprot_val(prot) & ~cc_mask); default: - return 0; + return prot; } } -u64 cc_mkenc(u64 val) +pgprot_t cc_mkdec(pgprot_t prot) { switch (cc_vendor) { case CC_VENDOR_AMD: - return val | cc_mask; + return __pgprot(pgprot_val(prot) & ~cc_mask); case CC_VENDOR_INTEL: - return val & ~cc_mask; + return __pgprot(pgprot_val(prot) | cc_mask); default: - return val; - } -} - -u64 cc_mkdec(u64 val) -{ - switch (cc_vendor) { - case CC_VENDOR_AMD: - return val & ~cc_mask; - case CC_VENDOR_INTEL: - return val | cc_mask; - default: - return val; + return prot; } } EXPORT_SYMBOL_GPL(cc_mkdec); diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c index 65a27dec095f..1ef63ea377dd 100644 --- a/arch/x86/mm/pat/set_memory.c +++ b/arch/x86/mm/pat/set_memory.c @@ -1999,8 +1999,8 @@ 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 = __pgprot(cc_get_mask(enc)); - cpa.mask_clr = __pgprot(cc_get_mask(!enc)); + cpa.mask_set = enc ? cc_mkenc(__pgprot(0)) : cc_mkdec(__pgprot(0)); + cpa.mask_clr = enc ? cc_mkdec(__pgprot(0)) : cc_mkenc(__pgprot(0)); cpa.pgd = init_mm.pgd; /* Must avoid aliasing mappings in the highmem code */ -- Kirill A. Shutemov
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