qemu: allow restore with non-migratable XML input

Convert input XML to migratable before using it in
qemuDomainSaveImageOpen.

XML in the save image is migratable, i.e. doesn't contain implicit
controllers. If these controllers were in a non-default order in the
input XML, the ABI check would fail. Removing and re-adding these
controllers fixes it.

https://bugzilla.redhat.com/show_bug.cgi?id=834196

src/qemu/qemu_domain.c

@@ -1275,6 +1275,35 @@ void qemuDomainObjExitRemote(virDomainObjPtr obj)
 }
 
 
+virDomainDefPtr
+qemuDomainDefCopy(virQEMUDriverPtr driver,
+                  virDomainDefPtr src,
+                  unsigned int flags)
+{
+    virBuffer buf = VIR_BUFFER_INITIALIZER;
+    virDomainDefPtr ret = NULL;
+    virCapsPtr caps = NULL;
+    const char *xml = NULL;
+
+    if (qemuDomainDefFormatBuf(driver, src, flags, &buf) < 0)
+        goto cleanup;
+
+    xml = virBufferContentAndReset(&buf);
+
+    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
+        goto cleanup;
+
+    if (!(ret = virDomainDefParseString(xml, caps, driver->xmlopt,
+                                        QEMU_EXPECTED_VIRT_TYPES,
+                                        VIR_DOMAIN_XML_INACTIVE)))
+        goto cleanup;
+
+cleanup:
+    VIR_FREE(xml);
+    virObjectUnref(caps);
+    return ret;
+}
+
 int
 qemuDomainDefFormatBuf(virQEMUDriverPtr driver,
                        virDomainDefPtr def,

src/qemu/qemu_domain.h

@@ -241,6 +241,10 @@ void qemuDomainObjEnterRemote(virDomainObjPtr obj)
 void qemuDomainObjExitRemote(virDomainObjPtr obj)
     ATTRIBUTE_NONNULL(1);
 
+virDomainDefPtr qemuDomainDefCopy(virQEMUDriverPtr driver,
+                                  virDomainDefPtr src,
+                                  unsigned int flags);
+
 int qemuDomainDefFormatBuf(virQEMUDriverPtr driver,
                            virDomainDefPtr vm,
                            unsigned int flags,

src/qemu/qemu_driver.c

@@ -4877,17 +4877,24 @@ qemuDomainSaveImageOpen(virQEMUDriverPtr driver,
         goto error;
     if (xmlin) {
         virDomainDefPtr def2 = NULL;
+        virDomainDefPtr newdef = NULL;
 
         if (!(def2 = virDomainDefParseString(xmlin, caps, driver->xmlopt,
                                              QEMU_EXPECTED_VIRT_TYPES,
                                              VIR_DOMAIN_XML_INACTIVE)))
             goto error;
-        if (!virDomainDefCheckABIStability(def, def2)) {
+
-            virDomainDefFree(def2);
+        newdef = qemuDomainDefCopy(driver, def2, VIR_DOMAIN_XML_MIGRATABLE);
+        virDomainDefFree(def2);
+        if (!newdef)
+            goto error;
+
+        if (!virDomainDefCheckABIStability(def, newdef)) {
+            virDomainDefFree(newdef);
             goto error;
         }
         virDomainDefFree(def);
-        def = def2;
+        def = newdef;
     }
 
     VIR_FREE(xml);