commit 19d4e467707e187f6736f24a35f5a51275d869ce
Author: Michal Prívozník <mprivozn@redhat.com>
Date:   Thu Jan 28 14:13:32 2021 +0100

    conf: Improve virDomainVirtioOptionsCheckABIStability()
    
    The virDomainVirtioOptionsCheckABIStability() function is called
    from various ABI stability check functions. Every caller checks
    if both old and new definitions have virtio options set and only
    after that they call the function. This is suboptimal because:
    
      a) this check can be done in the function itself (making all
      callers shorter),
      b) is inherently wrong, because it doesn't catch case where one
      definition has virtio options set and the other doesn't.
    
    Do proper checks at the beginning of the function and simplify
    its calls.
    
    Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
    Reviewed-by: Ján Tomko <jtomko@redhat.com>

Index: libvirt-7.0.0/src/conf/domain_conf.c
===================================================================
--- libvirt-7.0.0.orig/src/conf/domain_conf.c
+++ libvirt-7.0.0/src/conf/domain_conf.c
@@ -21491,6 +21491,15 @@ static bool
 virDomainVirtioOptionsCheckABIStability(virDomainVirtioOptionsPtr src,
                                         virDomainVirtioOptionsPtr dst)
 {
+    if (!src && !dst)
+        return true;
+
+    if (!src || !dst) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                       _("Target device virtio options don't match the source"));
+        return false;
+    }
+
     if (src->iommu != dst->iommu) {
         virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                        _("Target device iommu option '%s' does not "
@@ -21575,8 +21584,7 @@ virDomainDiskDefCheckABIStability(virDom
         return false;
     }
 
-    if (src->virtio && dst->virtio &&
-        !virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
+    if (!virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
         return false;
 
     if (!virDomainDeviceInfoCheckABIStability(&src->info, &dst->info))
@@ -21635,8 +21643,7 @@ virDomainControllerDefCheckABIStability(
         }
     }
 
-    if (src->virtio && dst->virtio &&
-        !virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
+    if (!virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
         return false;
 
     if (!virDomainDeviceInfoCheckABIStability(&src->info, &dst->info))
@@ -21669,8 +21676,7 @@ virDomainFsDefCheckABIStability(virDomai
         return false;
     }
 
-    if (src->virtio && dst->virtio &&
-        !virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
+    if (!virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
         return false;
 
     if (!virDomainDeviceInfoCheckABIStability(&src->info, &dst->info))
@@ -21718,8 +21724,7 @@ virDomainNetDefCheckABIStability(virDoma
         return false;
     }
 
-    if (src->virtio && dst->virtio &&
-        !virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
+    if (!virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
         return false;
 
     if (!virDomainDeviceInfoCheckABIStability(&src->info, &dst->info))
@@ -21757,8 +21762,7 @@ virDomainInputDefCheckABIStability(virDo
         return false;
     }
 
-    if (src->virtio && dst->virtio &&
-        !virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
+    if (!virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
         return false;
 
     if (!virDomainDeviceInfoCheckABIStability(&src->info, &dst->info))
@@ -21857,8 +21861,7 @@ virDomainVideoDefCheckABIStability(virDo
         }
     }
 
-    if (src->virtio && dst->virtio &&
-        !virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
+    if (!virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
         return false;
 
     if (!virDomainDeviceInfoCheckABIStability(&src->info, &dst->info))
@@ -22071,8 +22074,7 @@ virDomainMemballoonDefCheckABIStability(
         return false;
     }
 
-    if (src->virtio && dst->virtio &&
-        !virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
+    if (!virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
         return false;
 
     if (!virDomainDeviceInfoCheckABIStability(&src->info, &dst->info))
@@ -22094,8 +22096,7 @@ virDomainRNGDefCheckABIStability(virDoma
         return false;
     }
 
-    if (src->virtio && dst->virtio &&
-        !virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
+    if (!virDomainVirtioOptionsCheckABIStability(src->virtio, dst->virtio))
         return false;
 
     if (!virDomainDeviceInfoCheckABIStability(&src->info, &dst->info))