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Commit 815af8d4 authored by Avi Kivity's avatar Avi Kivity Committed by Linus Torvalds
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[PATCH] KVM: MMU: Let the walker extract the target page gfn from the pte 



This fixes a problem where set_pte_common() looked for shadowed pages based on
the page directory gfn (a huge page) instead of the actual gfn being mapped.

Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 374cbac0

drivers/kvm/mmu.c

+4 −3
Original line number Diff line number Diff line
@@ -752,7 +752,8 @@ static inline void set_pte_common(struct kvm_vcpu *vcpu, 
			     u64 *shadow_pte,

			     gpa_t gaddr,

			     int dirty,

			     u64 access_bits)

			     u64 access_bits,

			     gfn_t gfn)

{

	hpa_t paddr;
@@ -779,10 +780,10 @@ static inline void set_pte_common(struct kvm_vcpu *vcpu, 
	if (access_bits & PT_WRITABLE_MASK) {

		struct kvm_mmu_page *shadow;



		shadow = kvm_mmu_lookup_page(vcpu, gaddr >> PAGE_SHIFT);

		shadow = kvm_mmu_lookup_page(vcpu, gfn);

		if (shadow) {

			pgprintk("%s: found shadow page for %lx, marking ro\n",

				 __FUNCTION__, (gfn_t)(gaddr >> PAGE_SHIFT));

				 __FUNCTION__, gfn);

			access_bits &= ~PT_WRITABLE_MASK;

			*shadow_pte &= ~PT_WRITABLE_MASK;

		}

drivers/kvm/paging_tmpl.h

+27 −14
Original line number Diff line number Diff line
@@ -62,6 +62,7 @@ struct guest_walker { 
	pt_element_t *table;

	pt_element_t *ptep;

	pt_element_t inherited_ar;

	gfn_t gfn;

};



/*
@@ -113,12 +114,23 @@ static void FNAME(walk_addr)(struct guest_walker *walker, 
		if (is_present_pte(*ptep) && !(*ptep &  PT_ACCESSED_MASK))

			*ptep |= PT_ACCESSED_MASK;



		if (!is_present_pte(*ptep) ||

		    walker->level == PT_PAGE_TABLE_LEVEL ||

		    (walker->level == PT_DIRECTORY_LEVEL &&

		     (*ptep & PT_PAGE_SIZE_MASK) &&

		     (PTTYPE == 64 || is_pse(vcpu))))

		if (!is_present_pte(*ptep))

			break;



		if (walker->level == PT_PAGE_TABLE_LEVEL) {

			walker->gfn = (*ptep & PT_BASE_ADDR_MASK)

				>> PAGE_SHIFT;

			break;

		}



		if (walker->level == PT_DIRECTORY_LEVEL

		    && (*ptep & PT_PAGE_SIZE_MASK)

		    && (PTTYPE == 64 || is_pse(vcpu))) {

			walker->gfn = (*ptep & PT_DIR_BASE_ADDR_MASK)

				>> PAGE_SHIFT;

			walker->gfn += PT_INDEX(addr, PT_PAGE_TABLE_LEVEL);

			break;

		}



		if (walker->level != 3 || is_long_mode(vcpu))

			walker->inherited_ar &= walker->table[index];
@@ -143,30 +155,29 @@ static void FNAME(release_walker)(struct guest_walker *walker) 
}



static void FNAME(set_pte)(struct kvm_vcpu *vcpu, u64 guest_pte,

			   u64 *shadow_pte, u64 access_bits)

			   u64 *shadow_pte, u64 access_bits, gfn_t gfn)

{

	ASSERT(*shadow_pte == 0);

	access_bits &= guest_pte;

	*shadow_pte = (guest_pte & PT_PTE_COPY_MASK);

	set_pte_common(vcpu, shadow_pte, guest_pte & PT_BASE_ADDR_MASK,

		       guest_pte & PT_DIRTY_MASK, access_bits);

		       guest_pte & PT_DIRTY_MASK, access_bits, gfn);

}



static void FNAME(set_pde)(struct kvm_vcpu *vcpu, u64 guest_pde,

			   u64 *shadow_pte, u64 access_bits,

			   int index)

			   u64 *shadow_pte, u64 access_bits, gfn_t gfn)

{

	gpa_t gaddr;



	ASSERT(*shadow_pte == 0);

	access_bits &= guest_pde;

	gaddr = (guest_pde & PT_DIR_BASE_ADDR_MASK) + PAGE_SIZE * index;

	gaddr = (gpa_t)gfn << PAGE_SHIFT;

	if (PTTYPE == 32 && is_cpuid_PSE36())

		gaddr |= (guest_pde & PT32_DIR_PSE36_MASK) <<

			(32 - PT32_DIR_PSE36_SHIFT);

	*shadow_pte = guest_pde & PT_PTE_COPY_MASK;

	set_pte_common(vcpu, shadow_pte, gaddr,

		       guest_pde & PT_DIRTY_MASK, access_bits);

		       guest_pde & PT_DIRTY_MASK, access_bits, gfn);

}



/*
@@ -214,10 +225,12 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, 
					*prev_shadow_ent |= PT_SHADOW_PS_MARK;

				FNAME(set_pde)(vcpu, *guest_ent, shadow_ent,

					       walker->inherited_ar,

				          PT_INDEX(addr, PT_PAGE_TABLE_LEVEL));

					       walker->gfn);

			} else {

				ASSERT(walker->level == PT_PAGE_TABLE_LEVEL);

				FNAME(set_pte)(vcpu, *guest_ent, shadow_ent, walker->inherited_ar);

				FNAME(set_pte)(vcpu, *guest_ent, shadow_ent,

					       walker->inherited_ar,

					       walker->gfn);

			}

			return shadow_ent;

		}
@@ -291,7 +304,7 @@ static int FNAME(fix_write_pf)(struct kvm_vcpu *vcpu, 
		return 0;

	}



	gfn = (*guest_ent & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;

	gfn = walker->gfn;

	if (kvm_mmu_lookup_page(vcpu, gfn)) {

		pgprintk("%s: found shadow page for %lx, marking ro\n",

			 __FUNCTION__, gfn);