Bug 1837495

Created attachment 1689905 [details]
libvirtd debug log

Description of problem:
Can't detach interface specified by its address but not mac


Version-Release number of selected component (if applicable):
libvirt-6.0.0-19.module+el8.2.1+6538+c148631f.s390x

How reproducible:
100%

Preconditions
Guest has two interfaces of same type but on different addresses, e.g.
A. Given iface.xml = 
<interface type='network'>
      <source network='default'/>
      <model type='virtio'/>
</interface>
B. Run virsh attach-device vm iface.xml twice on vm (previously without any interface devices).

Steps to Reproduce:
1. Add iface address of one of the interfaces to iface.xml, e.g.
<interface type='network'>
      <source network='default'/>
      <model type='virtio'/>
      <address type='ccw' cssid='0xfe' ssid='0x0' devno='0x0009'/>
</interface>
2. virsh detach-device vm iface.xml

Actual results:
error: Failed to detach device from iface.xml
error: operation failed: multiple matching devices found

Expected results:
Device detached successfully

Additional info:
1. The ccw addresses in dumpxml after B. were confirmed to be different (interfaces correctly attached)
2. Expected result can be established when running steps on x86_64 using pci type address.
3. Using <mac/> instead of <address/> in step 1. leads to correct results
4. libvirtd.log indicates src/conf/domain_conf.c->virDomainNetFindIdx is involved but that code makes explicit reference only to PCI:
int
virDomainNetFindIdx(virDomainDefPtr def, virDomainNetDefPtr net)
{
...
    bool PCIAddrSpecified = virDomainDeviceAddressIsValid(&net->info,
VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI);
 
    for (i = 0; i < def->nnets; i++) {
...
        if (PCIAddrSpecified &&
            !virPCIDeviceAddressEqual(&def->nets[i]->info.addr.pci,
                                      &net->info.addr.pci))
            continue;
 
        if (matchidx >= 0) {
            /* there were multiple matches on mac address, and no
             * qualifying guest-side PCI address was given, so we must
             * fail (NB: a USB address isn't adequate, since it may
             * specify only vendor and product ID, and there may be
             * multiples of those.
             */
            if (MACAddrSpecified) {
                virReportError(VIR_ERR_OPERATION_FAILED,
                               _("multiple devices matching MAC address %s found"),
                               virMacAddrFormat(&net->mac, mac));
            } else {
                virReportError(VIR_ERR_OPERATION_FAILED, "%s",
                               _("multiple matching devices found"));
            }
 
            return -1;
        }
 
        matchidx = i;
    }
 
    if (matchidx < 0) {
        if (MACAddrSpecified && PCIAddrSpecified) {
            virReportError(VIR_ERR_DEVICE_MISSING,
...
        } else if (PCIAddrSpecified) {
            virReportError(VIR_ERR_DEVICE_MISSING,
...
        } else if (MACAddrSpecified) {
            virReportError(VIR_ERR_DEVICE_MISSING,
                           _("no device matching MAC address %s found"),
                           virMacAddrFormat(&net->mac, mac));
        } else {
            virReportError(VIR_ERR_DEVICE_MISSING, "%s",
                           _("no matching device found"));
        }
    }
    return matchidx;
}