KVM: Add make_page_dirty() to kvm_clear_guest_page()

Every write access to guest pages should be tracked.
Signed-off-by: Dor Laor <dor.laor@qumranet.com>
Signed-off-by: Izik Eidus <izike@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/kvm_main.c

@@ -706,6 +706,7 @@ int kvm_clear_guest_page(struct kvm *kvm, gfn_t gfn, int offset, int len)
 
 	kunmap_atomic(page_virt, KM_USER0);
 	kvm_release_page(page);
+	mark_page_dirty(kvm, gfn);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_clear_guest_page);