Re: [libvirt] [PATCH v4 5/9] qemu: Allow hotplug of vhost-scsi device

Adjust the device string that is built for vhost-scsi devices so that it can be invoked from hotplug. From the QEMU command line, the file descriptors are expect to be numeric only. However, for hotplug, the file descriptors are expected to begin with at least one alphabetic character else this error occurs: # virsh attach-device guest_0001 ~/vhost.xml error: Failed to attach device from /root/vhost.xml error: internal error: unable to execute QEMU command 'getfd': Parameter 'fdname' expects a name not starting with a digit We also close the file descriptor in this case, so that shutting down the guest cleans up the host cgroup entries and allows future guests to use vhost-scsi devices. (Otherwise the guest will silently end.) Signed-off-by: Eric Farman <farman(a)linux.vnet.ibm.com&gt; --- src/qemu/qemu_hotplug.c | 164 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 164 insertions(+) diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index 0508c67..02e248f 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -2443,6 +2443,126 @@ qemuDomainAttachHostSCSIDevice(virConnectPtr conn, goto cleanup; } +static int +qemuDomainAttachSCSIVHostDevice(virQEMUDriverPtr driver, + virDomainObjPtr vm, + virDomainHostdevDefPtr hostdev) +{ + int ret = -1; + qemuDomainObjPrivatePtr priv = vm->privateData; + virErrorPtr orig_err; + virDomainDeviceDef dev = { VIR_DOMAIN_DEVICE_HOSTDEV, + { .hostdev = hostdev } }; + virDomainCCWAddressSetPtr ccwaddrs = NULL; + char *vhostfdName = NULL; + int vhostfd = -1; + char *devstr = NULL; + bool teardowncgroup = false; + bool teardownlabel = false; + bool releaseaddr = false; + + if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE_SCSI_GENERIC)) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("SCSI passthrough is not supported by this version of qemu")); + goto cleanup; + } + + if (qemuHostdevPrepareSCSIVHostDevices(driver, vm->def->name, &hostdev, 1) < 0) { + virDomainHostdevSubsysSCSIVHostPtr hostsrc = &hostdev->source.subsys.u.scsi_host; + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Unable to prepare scsi_host hostdev: %s"), + hostsrc->wwpn); + goto cleanup; + } + + if (qemuSetupHostdevCgroup(vm, hostdev) < 0) + goto cleanup; + teardowncgroup = true; + + if (virSecurityManagerSetHostdevLabel(driver->securityManager, + vm->def, hostdev, NULL) < 0) + goto cleanup; + teardownlabel = true; + + if (virSCSIVHostOpenVhostSCSI(&vhostfd) < 0) + goto cleanup; + + if (virAsprintf(&vhostfdName, "vhostfd-%d", vhostfd) < 0) + goto cleanup; + + if (hostdev->info->type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE) { + if (qemuDomainMachineIsS390CCW(vm->def) && + virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_VIRTIO_CCW)) + hostdev->info->type = VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW; + } + + if (hostdev->info->type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE || + hostdev->info->type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI) { + if (qemuDomainEnsurePCIAddress(vm, &dev) < 0) + goto cleanup; + } else if (hostdev->info->type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW) { + if (!(ccwaddrs = qemuDomainCCWAddrSetCreateFromDomain(vm->def))) + goto cleanup; + if (virDomainCCWAddressAssign(hostdev->info, ccwaddrs, + !hostdev->info->addr.ccw.assigned) < 0) + goto cleanup; + } + releaseaddr = true; + + if (qemuAssignDeviceHostdevAlias(vm->def, &hostdev->info->alias, -1) < 0) + goto cleanup; + + if (!(devstr = qemuBuildSCSIVHostHostdevDevStr(vm->def, + hostdev, + priv->qemuCaps, + vhostfdName))) + goto cleanup; + + if (VIR_REALLOC_N(vm->def->hostdevs, vm->def->nhostdevs + 1) < 0) + goto cleanup; + + qemuDomainObjEnterMonitor(driver, vm); + + if (qemuMonitorAddDeviceWithFd(priv->mon, devstr, vhostfd, vhostfdName) < 0) + goto exit_monitor; + + if (qemuDomainObjExitMonitor(driver, vm) < 0) + goto audit; + + vm->def->hostdevs[vm->def->nhostdevs++] = hostdev; + ret = 0; + + audit: + virDomainAuditHostdev(vm, hostdev, "attach", (ret == 0)); + + cleanup: + virDomainCCWAddressSetFree(ccwaddrs);