Commit da8dc75f authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Marcelo Tosatti
Browse files

KVM: MMU: fix kvm_mmu_slot_remove_write_access dropping intermediate W bits 



Only remove write access in the last sptes.

Signed-off-by: default avatarXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 38a778aa

arch/x86/kvm/mmu.c

+7 −2
Original line number Diff line number Diff line
@@ -3540,12 +3540,17 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot) 


		pt = sp->spt;

		for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {

			if (sp->role.level != PT_PAGE_TABLE_LEVEL

			    && is_large_pte(pt[i])) {

			if (!is_shadow_present_pte(pt[i]) ||

			      !is_last_spte(pt[i], sp->role.level))

				continue;



			if (is_large_pte(pt[i])) {

				drop_spte(kvm, &pt[i],

					  shadow_trap_nonpresent_pte);

				--kvm->stat.lpages;

				continue;

			}



			/* avoid RMW */

			if (is_writable_pte(pt[i]))

				update_spte(&pt[i], pt[i] & ~PT_WRITABLE_MASK);