Commit b64b3763 authored by Avi Kivity's avatar Avi Kivity
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KVM: MMU: Don't cache guest access bits in the shadow page table 



This was once used to avoid accessing the guest pte when upgrading
the shadow pte from read-only to read-write.  But usually we need
to set the guest pte dirty or accessed bits anyway, so this wasn't
really exploited.

Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent fd97dc51

drivers/kvm/mmu.c

+0 −8
Original line number Diff line number Diff line
@@ -97,14 +97,6 @@ static int dbg = 1; 
#define PT_SHADOW_PS_MARK (1ULL << PT_FIRST_AVAIL_BITS_SHIFT)

#define PT_SHADOW_IO_MARK (1ULL << PT_FIRST_AVAIL_BITS_SHIFT)



#define PT_SHADOW_WRITABLE_SHIFT (PT_FIRST_AVAIL_BITS_SHIFT + 1)

#define PT_SHADOW_WRITABLE_MASK (1ULL << PT_SHADOW_WRITABLE_SHIFT)



#define PT_SHADOW_USER_SHIFT (PT_SHADOW_WRITABLE_SHIFT + 1)

#define PT_SHADOW_USER_MASK (1ULL << (PT_SHADOW_USER_SHIFT))



#define PT_SHADOW_BITS_OFFSET (PT_SHADOW_WRITABLE_SHIFT - PT_WRITABLE_SHIFT)



#define VALID_PAGE(x) ((x) != INVALID_PAGE)



#define PT64_LEVEL_BITS 9

drivers/kvm/paging_tmpl.h

+0 −1
Original line number Diff line number Diff line
@@ -219,7 +219,6 @@ static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu, 


	spte |= PT_PRESENT_MASK | PT_ACCESSED_MASK | PT_DIRTY_MASK;

	spte |= *gpte & PT64_NX_MASK;

	spte |= access_bits << PT_SHADOW_BITS_OFFSET;

	if (!dirty)

		access_bits &= ~PT_WRITABLE_MASK;