On 01/07/2014 07:53 AM, Laine Stump wrote:
https://bugzilla.redhat.com/show_bug.cgi?id=1047429
The problem occurs when a host with a running guest is upgraded from pre-1.0.2 libvirt, and then a later attempt is made to hotplug a new PCI device (emulated or passthrough) to that guest without having power cycled / save-restored / migrated the guest. The hotplug fails with this error:
internal error: Device alias was not set for PCI controller with index 0 required for device at address 0000:00:xx.x
I'm not 100% convinced that it's necessary to handle *this* case either (upgrading from pre-1.0.2), but thought I should send the patch to the list anyway to see what others think. My opinion is that it's creating permanent clutter in the code in order to handle a situation that will come up just once in the entire lifetime of a host (and even then only if libvirt is upgraded without somehow restarting a guest, and *then* a device is hotplugged to that guest), so it may be better if we just left the workaround ("restart/save-restore/migrate the domain if you need to hotplug a device") as a footnote somewhere instead.
Yes, I think I could live with such a footnote. And even if we get outvoted and someone else requests the permanent code clutter, we can add that as a separate commit which gives the further justification of why we are adding it.
+ /* this could be a case where the domain had been + * started with an earlier version of libvirt that + * had no device entry for the PCI bus + * (pre-1.0.2), and in that case no alias would be + * set in the status XML, so we create one using + * the standard "pci.N" pattern. + */ + if (virAsprintf(&tempAlias, "pci.%u", info->addr.pci.bus) < 0) + goto cleanup; + contAlias = tempAlias;
contAlias and tempAlias point to the same location...
} break; } @@ -3118,6 +3123,7 @@ qemuBuildDeviceAddressStr(virBufferPtr buf, ret = 0; cleanup: VIR_FREE(devStr); + VIR_FREE(tempAlias);
and you then free tempAlias. That leaves contAlias pointing at stale memory. That doesn't feel right. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org