On 10/07/13 16:19, Laine Stump wrote:
On 10/04/2013 08:55 AM, Peter Krempa wrote:
Prefer using VFIO (if available) to the legacy KVM device passthrough.
With this patch a PCI passthrough device without the driver configured will be started with VFIO if it's available on the host. If not legacy KVM passthrough is checked and error is reported if it's not available. --- docs/formatdomain.html.in | 9 ++++----- src/conf/domain_conf.h | 2 +- src/qemu/qemu_command.c | 3 ++- src/qemu/qemu_hostdev.c | 21 +++++++++++++++++++-- src/qemu/qemu_hostdev.h | 3 ++- src/qemu/qemu_hotplug.c | 2 +- src/qemu/qemu_process.c | 15 ++++++++------- tests/qemuxml2argvtest.c | 11 +++++++++++ 8 files changed, 48 insertions(+), 18 deletions(-)
...
diff --git a/src/qemu/qemu_hostdev.c b/src/qemu/qemu_hostdev.c index dbbc2b4..ad408d8 100644 --- a/src/qemu/qemu_hostdev.c +++ b/src/qemu/qemu_hostdev.c @@ -1366,7 +1366,8 @@ qemuHostdevHostSupportsPassthroughLegacy(void)
bool qemuHostdevHostVerifySupport(virDomainHostdevDefPtr *hostdevs, - size_t nhostdevs) + size_t nhostdevs, + virQEMUCapsPtr qemuCaps)
Aha. I guess if you follow my recommendation in 2/3, you'll need to pass qemuCaps down through the qemuPrepareHostDevices() call chain (and I don't think that's a bad thing).
Seems doable. I will post another version incorporating that.
{ int supportsPassthroughKVM = -1; int supportsPassthroughVFIO = -1; @@ -1387,6 +1388,23 @@ qemuHostdevHostVerifySupport(virDomainHostdevDefPtr *hostdevs, }
switch ((virDomainHostdevSubsysPciBackendType) *backend) { + case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_DEFAULT: + if (supportsPassthroughVFIO && + virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_VFIO_PCI)) { + *backend = VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO; + } else if (supportsPassthroughKVM && + (virQEMUCapsGet(qemuCaps, QEMU_CAPS_PCIDEVICE) || + virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE))) { + *backend = VIR_DOMAIN_HOSTDEV_PCI_BACKEND_KVM; + } else { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("host doesn't support passthrough of " + "host PCI devices")); + return false; + } + + break; +
Ah! And there is the separate case I was asking for in 2/3!
But you're changing the "backend" in the data itself - that will lead to incorrect display when someone does a dumpxml (will it cause problems if someone loads the vfio driver? I guess not, since this should only be the "live" data, not the persistent data)
Hmm, Is this an issue? I think it might be useful to update the info in the live XML so that the users are notified. If we don't want to do this I will change it in the next version. Peter