KVM: Move guest pte dirty bit management to the guest pagetable walker

This is more consistent with the accessed bit management, and makes the dirty
bit available earlier for other purposes.

Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 8 insertions, 23 deletions

diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h
index 8e1e4ca..da36e48 100644
--- a/drivers/kvm/paging_tmpl.h
+++ b/drivers/kvm/paging_tmpl.h
@@ -144,6 +144,10 @@ static int FNAME(walk_addr)(struct guest_walker *walker,
 		if (walker->level == PT_PAGE_TABLE_LEVEL) {
 			walker->gfn = (*ptep & PT_BASE_ADDR_MASK)
 				>> PAGE_SHIFT;
+			if (write_fault && !is_dirty_pte(*ptep)) {
+				mark_page_dirty(vcpu->kvm, table_gfn);
+				*ptep |= PT_DIRTY_MASK;
+			}
 			break;
 		}
 
@@ -153,6 +157,10 @@ static int FNAME(walk_addr)(struct guest_walker *walker,
 			walker->gfn = (*ptep & PT_DIR_BASE_ADDR_MASK)
 				>> PAGE_SHIFT;
 			walker->gfn += PT_INDEX(addr, PT_PAGE_TABLE_LEVEL);
+			if (write_fault && !is_dirty_pte(*ptep)) {
+				mark_page_dirty(vcpu->kvm, table_gfn);
+				*ptep |= PT_DIRTY_MASK;
+			}
 			break;
 		}
 
@@ -194,12 +202,6 @@ err:
 	return 0;
 }
 
-static void FNAME(mark_pagetable_dirty)(struct kvm *kvm,
-					struct guest_walker *walker)
-{
-	mark_page_dirty(kvm, walker->table_gfn[walker->level - 1]);
-}
-
 static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu,
 				  u64 *shadow_pte,
 				  gpa_t gaddr,
@@ -221,23 +223,6 @@ static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu,
 		 __FUNCTION__, *shadow_pte, (u64)gpte, access_bits,
 		 write_fault, user_fault, gfn);
 
-	if (write_fault && !dirty) {
-		pt_element_t *guest_ent, *tmp = NULL;
-
-		if (walker->ptep)
-			guest_ent = walker->ptep;
-		else {
-			tmp = kmap_atomic(walker->page, KM_USER0);
-			guest_ent = &tmp[walker->index];
-		}
-
-		*guest_ent |= PT_DIRTY_MASK;
-		if (!walker->ptep)
-			kunmap_atomic(tmp, KM_USER0);
-		dirty = 1;
-		FNAME(mark_pagetable_dirty)(vcpu->kvm, walker);
-	}
-
 	/*
 	 * We don't set the accessed bit, since we sometimes want to see
 	 * whether the guest actually used the pte (in order to detect