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Commit c2e3277f authored by Rusty Russell's avatar Rusty Russell Committed by Ingo Molnar
Browse files

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 a15af1c9 '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: default avatarRusty Russell <rusty@rustcorp.com.au>
Acked-by: default avatarJeremy Fitzhardinge <jeremy@goop.org>
Signed-off-and-morning-tea-spilled-by: default avatarIngo Molnar <mingo@elte.hu>
parent 988781dc

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;

}