[libvirt] [PATCH v3] qemu: qemuDomainChangeNet: validity checks should be done before XML autocompletion

[Katerina Koukiou]

This patch ensures that changes in attributes of interfaces will be emit
errors accept if they are missing from the XML.
Previously we were falsely reporting successful updates, because some
changed attributes got overwritten before the validity checks.

https://bugzilla.redhat.com/show_bug.cgi?id=1599513

Signed-off-by: Katerina Koukiou <kkoukiou at redhat.com>
---
Changes from v2:
* Added check for type element in info struct.
* Moved the addr checks at start the the section with info checks.


 src/qemu/qemu_hotplug.c | 34 ++++++++++++++++++++++++++--------
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 0b84a503bb..f9805627b7 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -3598,16 +3598,22 @@ qemuDomainChangeNet(virQEMUDriverPtr driver,
         goto cleanup;
     }
 
-    /* info: if newdev->info is empty, fill it in from olddev,
-     * otherwise verify that it matches - nothing is allowed to
-     * change. (There is no helper function to do this, so
-     * individually check the few feidls of virDomainDeviceInfo that
-     * are relevant in this case).
+    /* info: Nothing is allowed to change. First fill the missing newdev->info
+     * from olddev and then check for changes.
      */
+
+    /* if addr type is missing overwrite if from olddev */
+    if (newdev->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE)
+        newdev->info.type = olddev->info.type;
+    if (olddev->info.type != newdev->info.type) {
+        virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+                       _("cannot modify network device type"));
+    }
+
+    /* if pci addr is missing or is invalid we overwrite it from olddev */
     if (!virDomainDeviceAddressIsValid(&newdev->info,
-                                       VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI) &&
-        virDomainDeviceInfoCopy(&newdev->info, &olddev->info) < 0) {
-        goto cleanup;
+                                       VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI)) {
+        newdev->info.addr.pci = olddev->info.addr.pci;
     }
     if (!virPCIDeviceAddressEqual(&olddev->info.addr.pci,
                                   &newdev->info.addr.pci)) {
@@ -3622,21 +3628,33 @@ qemuDomainChangeNet(virQEMUDriverPtr driver,
 
     /* device alias is checked already in virDomainDefCompatibleDevice */
 
+    if (newdev->info.rombar == VIR_TRISTATE_BOOL_ABSENT)
+        newdev->info.rombar = olddev->info.rombar;
     if (olddev->info.rombar != newdev->info.rombar) {
         virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
                        _("cannot modify network device rom bar setting"));
         goto cleanup;
     }
+
+    if (!newdev->info.romfile &&
+        VIR_STRDUP(newdev->info.romfile, olddev->info.romfile) < 0)
+        goto cleanup;
     if (STRNEQ_NULLABLE(olddev->info.romfile, newdev->info.romfile)) {
         virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
                        _("cannot modify network rom file"));
         goto cleanup;
     }
+
+    if (newdev->info.bootIndex == 0)
+        newdev->info.bootIndex = olddev->info.bootIndex;
     if (olddev->info.bootIndex != newdev->info.bootIndex) {
         virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
                        _("cannot modify network device boot index setting"));
         goto cleanup;
     }
+
+    if (newdev->info.romenabled == VIR_TRISTATE_BOOL_ABSENT)
+        newdev->info.romenabled = olddev->info.romenabled;
     if (olddev->info.romenabled != newdev->info.romenabled) {
         virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
                        _("cannot modify network device rom enabled setting"));
-- 
2.17.1