[libvirt] [PATCHv2 08/12] qemu: don't reset PCI devices being assigned with VFIO
Daniel P. Berrange
berrange at redhat.com
Tue Jun 25 10:44:01 UTC 2013
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
> qemuReattachPciDevice(activePci, driver);
> ret = 0;
> } else {
ACK
Daniel
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