RE: [PATCH] qemu: Fix domxml-to-native command failure

-----Original Message----- From: Michal Prívozník <mprivozn(a)redhat.com&gt; Sent: Thursday, April 13, 2023 4:21 PM To: Duan, Zhenzhong <zhenzhong.duan(a)intel.com>; libvir-list(a)redhat.com Subject: Re: [PATCH] qemu: Fix domxml-to-native command failure On 4/13/23 08:07, Zhenzhong Duan wrote: > virsh command domxml-to-native failed with below error but start > command suceed for same domain xml. > > "internal error: invalid PCI passthrough type 'default'" > > If host pci device's driver attribute isn't defined in domain xml, > qemu driver will choose a proper value based on host environment > before starting qemu process. But this is missed in domxml-to-native > command, add the same logic so domxml-to-native could pass. > > Signed-off-by: Zhenzhong Duan <zhenzhong.duan(a)intel.com&gt; > --- > src/qemu/qemu_domain.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index > 63b13b6875c9..517c90f93f0a 100644 > --- a/src/qemu/qemu_domain.c > +++ b/src/qemu/qemu_domain.c > @@ -11274,6 +11274,17 @@ qemuDomainPrepareHostdev(virDomainHostdevDef *hostdev, > } > } > } > + if (hostdev->mode == VIR_DOMAIN_HOSTDEV_MODE_SUBSYS && > + hostdev->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_PCI) { > + bool supportsPassthroughVFIO = qemuHostdevHostSupportsPassthroughVFIO(); > + virDomainHostdevSubsysPCIBackendType *backend = > + &hostdev->source.subsys.u.pci.backend; > + > + if (*backend == VIR_DOMAIN_HOSTDEV_PCI_BACKEND_DEFAULT && > + supportsPassthroughVFIO && > + virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE_VFIO_PCI)) { > + *backend = VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO; > + } > + } > The same happens in qemuHostdevPreparePCIDevicesCheckSupport(). Should we remove the code from there and leave just checks there? I mean, if choosing the backend is moved here, as you suggests, then qemuHostdevPreparePCIDevicesCheckSupport() shouldn't ever see a hostdev with VIR_DOMAIN_HOSTDEV_PCI_BACKEND_DEFAULT. Except when the host doesn't support VFIO. So maybe just drop the code that sets backend an replace it with a virReportError();