Fix cleanup path if an HVM guest fails very early, before direct map is built.

Signed-off-by: Xin Li <xin.b.li@intel.com>

diff --git a/xen/arch/x86/shadow32.c b/xen/arch/x86/shadow32.c
index fe58ed94538777c492eb7b8d042e77fa41afce3b..5264b0359b144b93724c2f354f879702efcb0acf 100644 (file)
--- a/xen/arch/x86/shadow32.c
+++ b/xen/arch/x86/shadow32.c
@@ -1110,22 +1110,30 @@ fail:
 void shadow_direct_map_clean(struct vcpu *v)
 {
     int i;
+    unsigned long mfn;
+    struct domain *d = v->domain;
     l2_pgentry_t *l2e;
 
-    l2e = map_domain_page(
-      pagetable_get_pfn(v->domain->arch.phys_table));
+    mfn =  pagetable_get_pfn(d->arch.phys_table);
+
+    /*
+     * We may fail very early before direct map is built.
+     */
+    if ( !mfn )
+        return;
+
+    l2e = map_domain_page(mfn);
 
     for ( i = 0; i < L2_PAGETABLE_ENTRIES; i++ )
     {
         if ( l2e_get_flags(l2e[i]) & _PAGE_PRESENT )
             free_domheap_page(mfn_to_page(l2e_get_pfn(l2e[i])));
     }
-
-    free_domheap_page(
-            mfn_to_page(pagetable_get_pfn(v->domain->arch.phys_table)));
+    free_domheap_page(mfn_to_page(mfn));
 
     unmap_domain_page(l2e);
-    v->domain->arch.phys_table = mk_pagetable(0);
+
+    d->arch.phys_table = mk_pagetable(0);
 }
 
 int __shadow_mode_enable(struct domain *d, unsigned int mode)

diff --git a/xen/arch/x86/shadow_public.c b/xen/arch/x86/shadow_public.c
index e87188153a9b71570e47c028cbedc14fe966a05f..7dfe111f2f569dcc52391bc04eb938b719be3673 100644 (file)
--- a/xen/arch/x86/shadow_public.c
+++ b/xen/arch/x86/shadow_public.c
@@ -59,12 +59,21 @@ fail:
 
 void shadow_direct_map_clean(struct vcpu *v)
 {
+    unsigned long mfn;
+    struct domain *d = v->domain;
     l2_pgentry_t *l2e;
     l3_pgentry_t *l3e;
     int i, j;
 
-    l3e = (l3_pgentry_t *)map_domain_page(
-        pagetable_get_pfn(v->domain->arch.phys_table));
+    mfn = pagetable_get_pfn(d->arch.phys_table);
+
+    /*
+     * We may fail very early before direct map is built.
+     */
+    if ( !mfn )
+        return;
+
+    l3e = (l3_pgentry_t *)map_domain_page(mfn);
 
     for ( i = 0; i < PAE_L3_PAGETABLE_ENTRIES; i++ )
     {
@@ -81,12 +90,11 @@ void shadow_direct_map_clean(struct vcpu *v)
             free_domheap_page(mfn_to_page(l3e_get_pfn(l3e[i])));
         }
     }
-
-    free_domheap_page(
-        mfn_to_page(pagetable_get_pfn(v->domain->arch.phys_table)));
+    free_domheap_page(mfn_to_page(mfn));
 
     unmap_domain_page(l3e);
-    v->domain->arch.phys_table = mk_pagetable(0);
+
+    d->arch.phys_table = mk_pagetable(0);
 }
 
 /****************************************************************************/