Commit cc70e737 authored by Avi Kivity's avatar Avi Kivity
Browse files

KVM: MMU: Disable write access on clean large pages 



By forcing clean huge pages to be read-only, we have separate roles
for the shadow of a clean large page and the shadow of a dirty large
page.  This is necessary because different ptes will be instantiated
for the two cases, even for read faults.

Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent c22e3514

drivers/kvm/paging_tmpl.h

+2 −0
Original line number Diff line number Diff line
@@ -382,6 +382,8 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, 
			metaphysical = 1;

			hugepage_access = walker->pte;

			hugepage_access &= PT_USER_MASK | PT_WRITABLE_MASK;

			if (!is_dirty_pte(walker->pte))

				hugepage_access &= ~PT_WRITABLE_MASK;

			hugepage_access >>= PT_WRITABLE_SHIFT;

			if (walker->pte & PT64_NX_MASK)

				hugepage_access |= (1 << 2);