Re: [libvirt] [libvirt-tck PATCH] Fix PCI device hotplug tests

Eric Blake wrote: > On 10/23/2014 03:21 PM, Jim Fehlig wrote: > >> This patch fixes a few issues noted while enabling the TCK PCI device >> hotplug tests. >> >> First, the call to node device dettach function misses parameters, resulting >> in the following failure >> >> Failed test 'detached device from host OS' >> at /usr/share/libvirt-tck/tests/domain/250-pci-host-hotplug.t line 90. >> died: Usage: Sys::Virt::NodeDevice::dettach(dev, driversv, flags=0) >> at /usr/share/libvirt-tck/tests/domain/250-pci-host-hotplug.t line 90. >> >> Trivally fixed by adding the missing parameters when calling node device >> dettach function. >> > > That part is fine to fix (note that 'dettach' is a typo but part of the > API, so we are stuck with it; it's nice to use 'detach' where possible). > > >> Second, it appears qemu needs to reach some state of initialization before >> host device attach/detach works properly. Currently, the test fails when >> detaching the device from the guest, resetting it, and reattaching it to >> the host >> >> Failed test 'reset the host PCI device' >> at /usr/share/libvirt-tck/tests/domain/250-pci-host-hotplug.t line 110. >> died: Sys::Virt::Error (libvirt error code: 1, message: internal error: >> Not resetting active device 0000:03:00.1) >> >> Failed test 'reattached device to host OS' >> at /usr/share/libvirt-tck/tests/domain/250-pci-host-hotplug.t line 111. >> died: Sys::Virt::Error (libvirt error code: 55, message: Requested operation >> is not valid: PCI device 0000:03:00.1 is still in use by driver QEMU, domain >> tck) >> >> I've found that sleeping for a bit after creating the guest allows the >> tests to pass. >> > > But that papers over the bug. Ideally, the libvirt API should be > waiting longer for the guest to relinquish control of the device before > returning success on the first call, so that the second call cannot hit > a collision. Even with this delay, the guest has not completely booted when the test successfully completes. So it is not clear to me how much guest cooperation is needed. > I'm not so sure that this is the right patch to make to > TCK, and wonder if we should instead be patching libvirt proper. Or is > it a case that because detach requires guest cooperation, we need to > wait long enough for the guest to boot to the point that it can > cooperate? Perhaps. Maybe acpiphp needs to be loaded in the guest kernel before this will work.