On Tue, Jun 25, 2013 at 01:06:55PM -0400, Laine Stump wrote:
On 06/25/2013 06:44 AM, Daniel P. Berrange wrote:
On Mon, Jun 24, 2013 at 11:05:34PM -0400, Laine Stump wrote:
I just learned that VFIO resets PCI devices when they are assigned to guests / returned to the host, so it is redundant for libvirt to reset the devices. This patch inhibits calling virPCIDeviceReset to devices that will be/were assigned using VFIO. --- src/qemu/qemu_hostdev.c | 4 ++++ src/qemu/qemu_hotplug.c | 5 +++-- 2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/src/qemu/qemu_hostdev.c b/src/qemu/qemu_hostdev.c index dfe39c6..d7d54d7 100644 --- a/src/qemu/qemu_hostdev.c +++ b/src/qemu/qemu_hostdev.c @@ -548,6 +548,8 @@ int qemuPrepareHostdevPCIDevices(virQEMUDriverPtr driver, * can safely reset them */ for (i = 0; i < virPCIDeviceListCount(pcidevs); i++) { virPCIDevicePtr dev = virPCIDeviceListGet(pcidevs, i); + if (STREQ_NULLABLE(virPCIDeviceGetStubDriver(dev), "vfio-pci")) + continue; if (virPCIDeviceReset(dev, driver->activePciHostdevs, driver->inactivePciHostdevs) < 0) goto reattachdevs; @@ -1114,6 +1116,8 @@ void qemuDomainReAttachHostdevDevices(virQEMUDriverPtr driver,
for (i = 0; i < virPCIDeviceListCount(pcidevs); i++) { virPCIDevicePtr dev = virPCIDeviceListGet(pcidevs, i); + if (STREQ_NULLABLE(virPCIDeviceGetStubDriver(dev), "vfio-pci")) + continue; if (virPCIDeviceReset(dev, driver->activePciHostdevs, driver->inactivePciHostdevs) < 0) { virErrorPtr err = virGetLastError(); diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index 18f5fa5..46875ad 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -2528,8 +2528,9 @@ qemuDomainDetachHostPciDevice(virQEMUDriverPtr driver, if (pci) { activePci = virPCIDeviceListSteal(driver->activePciHostdevs, pci); if (activePci && - virPCIDeviceReset(activePci, driver->activePciHostdevs, - driver->inactivePciHostdevs) == 0) { + (subsys->u.pci.backend == VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO || + virPCIDeviceReset(activePci, driver->activePciHostdevs, + driver->inactivePciHostdevs) == 0)) { I'm guessing that virPCIDeviceGetStubDriver() isn't returning 'pci-stub' here, right ? Otherwise you'd would have used the same pattern as earlier
No, the stub driver should be set correctly at this time[*]. It was just a case of having multiple options for learning the answer in this case, and choosing the one that's more efficient.
Ok, so where I was going here, was that if the the virPCIDevicePtr object has enough info, then could we make virPCIDeviceReset() look for stub == vfio-pci, and make itself a nop. This avoids the risk of one caller forgetting to do the check itself. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|