Messages in this thread Patch in this message | | | From | Rusty Russell <> | Subject | [PATCH] x86: fix pte_flags() to only return flags, fix lguest (updated) | Date | Tue, 22 Jul 2008 15:40:46 +1000 |
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(Jeremy said: rusty: use PTE_MASK rusty: use PTE_MASK rusty: use PTE_MASK When I asked: jsgf: does that include the NX flag? He responded eloquently: rusty: use PTE_MASK rusty: use PTE_MASK yes, it's the official constant of masking flags out of ptes )
Change a15af1c9ea2750a9ff01e51615c45950bad8221b 'x86/paravirt: add pte_flags to just get pte flags' removed lguest's private pte_flags() in favor of a generic one.
Unfortunately, the generic one doesn't filter out the non-flags bits: this results in lguest creating corrupt shadow page tables and blowing up host memory.
Since noone is supposed to use the pfn part of pte_flags(), it seems safest to always do the filtering.
Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff -r ee1a6adad3d2 arch/x86/kernel/paravirt.c --- a/arch/x86/kernel/paravirt.c Mon Jul 21 12:49:25 2008 +1000 +++ b/arch/x86/kernel/paravirt.c Tue Jul 22 15:31:04 2008 +1000 @@ -428,7 +428,7 @@ struct pv_mmu_ops pv_mmu_ops = { #endif /* PAGETABLE_LEVELS >= 3 */ .pte_val = native_pte_val, - .pte_flags = native_pte_val, + .pte_flags = native_pte_flags, .pgd_val = native_pgd_val, .make_pte = native_make_pte, diff -r ee1a6adad3d2 include/asm-x86/page.h --- a/include/asm-x86/page.h Mon Jul 21 12:49:25 2008 +1000 +++ b/include/asm-x86/page.h Tue Jul 22 15:31:04 2008 +1000 @@ -144,6 +144,11 @@ static inline pteval_t native_pte_val(pt return pte.pte; } +static inline pteval_t native_pte_flags(pte_t pte) +{ + return native_pte_val(pte) & ~PTE_MASK; +} + #define pgprot_val(x) ((x).pgprot) #define __pgprot(x) ((pgprot_t) { (x) } ) @@ -165,7 +170,7 @@ static inline pteval_t native_pte_val(pt #endif #define pte_val(x) native_pte_val(x) -#define pte_flags(x) native_pte_val(x) +#define pte_flags(x) native_pte_flags(x) #define __pte(x) native_make_pte(x) #endif /* CONFIG_PARAVIRT */ diff -r ee1a6adad3d2 include/asm-x86/paravirt.h --- a/include/asm-x86/paravirt.h Mon Jul 21 12:49:25 2008 +1000 +++ b/include/asm-x86/paravirt.h Tue Jul 22 15:31:04 2008 +1000 @@ -1083,6 +1083,9 @@ static inline pteval_t pte_flags(pte_t p ret = PVOP_CALL1(pteval_t, pv_mmu_ops.pte_flags, pte.pte); +#ifdef CONFIG_PARAVIRT_DEBUG + BUG_ON(ret & PTE_MASK); +#endif return ret; }
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