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>

diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index d046ba8077631b2cee91badfc4d19eac2a8a9fd2..e6616a6c9cefbdabaf1ebeddc6fd44a607d60e33 100644 (file)
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -199,6 +199,11 @@ static int is_writeble_pte(unsigned long pte)
        return pte & PT_WRITABLE_MASK;
 }
 
+static int is_dirty_pte(unsigned long pte)
+{
+       return pte & PT_DIRTY_MASK;
+}
+
 static int is_io_pte(unsigned long pte)
 {
        return pte & PT_SHADOW_IO_MARK;

diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h
index 8e1e4ca6ea4eb2e42ec49cb43ba47be743c9e755..da36e48fd026b67bc5ad6ee2dc3f2e01b311bb85 100644 (file)
--- 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