RE: [PATCH v2] qemu: Fix domxml-to-native command failure

-----Original Message----- From: Michal Prívozník <mprivozn(a)redhat.com&gt; Sent: Friday, April 14, 2023 9:06 PM To: Duan, Zhenzhong <zhenzhong.duan(a)intel.com>; libvir-list(a)redhat.com Cc: Peng, Chao P <chao.p.peng(a)intel.com&gt; Subject: Re: [PATCH v2] qemu: Fix domxml-to-native command failure On 4/14/23 07:34, Zhenzhong Duan wrote: > virsh command domxml-to-native failed with below error but start > command succeed 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 and replace > the relevant code in qemuHostdevPreparePCIDevicesCheckSupport() with > an error report. > > Signed-off-by: Zhenzhong Duan <zhenzhong.duan(a)intel.com&gt; > --- > v2: replace setting with an error report, suggested by Michal > > src/qemu/qemu_domain.c | 11 +++++++++++ src/qemu/qemu_hostdev.c | > 8 ++++---- > 2 files changed, 15 insertions(+), 4 deletions(-) > > 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; > + } > + } > > return 0; > } > diff --git a/src/qemu/qemu_hostdev.c b/src/qemu/qemu_hostdev.c index > 45cd1066f0a5..305a323a0769 100644 > --- a/src/qemu/qemu_hostdev.c > +++ b/src/qemu/qemu_hostdev.c > @@ -175,15 +175,15 @@ qemuHostdevPreparePCIDevicesCheckSupport(virDomainHostdevDef **hostdevs, > case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_DEFAULT: > if (supportsPassthroughVFIO && > virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_VFIO_PCI)) { > - *backend = VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO; > + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", > + _("qemuDomainPrepareHostdev() should have set backend " > + "to > + VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO")); Ha! I've found one path where the backend is not set: qemuDomainAttachHostPCIDevice(). So we need a bit more code movement. But after that, this branch is effectively a dead code.

In fact, if we move things a bit a lot of code will become dead. So let me respin with more patches.