From c2e3277f875b83e5adc34e96989d6d87ec5f80f7 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 22 Jul 2008 15:40:46 +1000 Subject: [PATCH] x86: fix pte_flags() to only return flags, fix lguest (updated) (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. Signed-off-by: Rusty Russell Acked-by: Jeremy Fitzhardinge Signed-off-and-morning-tea-spilled-by: Ingo Molnar --- arch/x86/kernel/paravirt.c | 2 +- include/asm-x86/page.h | 7 ++++++- include/asm-x86/paravirt.h | 3 +++ 3 files changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index 097d8a6797f..94da4d52d79 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -443,7 +443,7 @@ 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 --git a/include/asm-x86/page.h b/include/asm-x86/page.h index 28d7b4533b1..05d9bea2bfd 100644 --- a/include/asm-x86/page.h +++ b/include/asm-x86/page.h @@ -144,6 +144,11 @@ static inline pteval_t native_pte_val(pte_t pte) 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(pte_t pte) #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 --git a/include/asm-x86/paravirt.h b/include/asm-x86/paravirt.h index aec9767836b..5ca4639dc7d 100644 --- a/include/asm-x86/paravirt.h +++ b/include/asm-x86/paravirt.h @@ -1088,6 +1088,9 @@ static inline pteval_t pte_flags(pte_t pte) ret = PVOP_CALL1(pteval_t, pv_mmu_ops.pte_flags, pte.pte); +#ifdef CONFIG_PARAVIRT_DEBUG + BUG_ON(ret & PTE_MASK); +#endif return ret; } -- 2.41.0