x86: fix pte_flags() to only return flags, fix lguest (updated) (c2e3277f) · Commits · 戴 / test

(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 '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 <rusty@rustcorp.com.au> Acked-by:

Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-and-morning-tea-spilled-by:

Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/paravirt.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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,

include/asm-x86/page.h

+6 −1

Original line number	Diff line number	Diff line
		@@ -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 */

include/asm-x86/paravirt.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -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;
		}

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