Re: [libvirt] [PATCHv3 07/11] qemu: Allow multiple vhost-net openings

With multiqueue network feature, we are advised to pass multiple vhost-net FDs as well. The ratio should be 1:1. Therefore we must alter the qemuOpenVhostNet function to allow that. --- src/qemu/qemu_command.c | 60 ++++++++++++++++++++++++++++++++++++------------- src/qemu/qemu_command.h | 3 ++- src/qemu/qemu_hotplug.c | 12 ++++++---- 3 files changed, 54 insertions(+), 21 deletions(-) diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index a053d49..ec66a33 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -405,17 +405,34 @@ cleanup: } +/** + * qemuOpenVhostNet: + * @def: domain definition + * @net: network definition + * @qemuCaps: qemu binary capabilities + * @vhostfd: array of opened vhost-net device + * @vhostfdSize: size of @vhostfd array

+ * + * Open vhost-net, multiple times - if requested. + * In case, no vhost-net is needed, @vhostfdSize is set to 0 + * and 0 is returned. + * + * Returns: 0 on success + * -1 on failure + */ int qemuOpenVhostNet(virDomainDefPtr def, virDomainNetDefPtr net, virQEMUCapsPtr qemuCaps, - int *vhostfd) + int *vhostfd, + int *vhostfdSize) { - *vhostfd = -1; /* assume we won't use vhost */ + int i; /* If the config says explicitly to not use vhost, return now */ if (net->driver.virtio.name == VIR_DOMAIN_NET_BACKEND_TYPE_QEMU) { - return 0; + *vhostfdSize = 0; + return 0; } /* If qemu doesn't support vhost-net mode (including the -netdev command @@ -430,6 +447,7 @@ qemuOpenVhostNet(virDomainDefPtr def, "this QEMU binary")); return -1; } + *vhostfdSize = 0; return 0; } @@ -441,23 +459,32 @@ qemuOpenVhostNet(virDomainDefPtr def, "virtio network interfaces")); return -1; } + *vhostfdSize = 0; return 0; } - *vhostfd = open("/dev/vhost-net", O_RDWR); - virDomainAuditNetDevice(def, net, "/dev/vhost-net", *vhostfd >= 0); + for (i = 0; i < *vhostfdSize; i++) { + vhostfd[i] = open("/dev/vhost-net", O_RDWR); + virDomainAuditNetDevice(def, net, "/dev/vhost-net", vhostfd[i] >= 0); - /* If the config says explicitly to use vhost and we couldn't open it, - * report an error. - */ - if ((*vhostfd < 0) && - (net->driver.virtio.name == VIR_DOMAIN_NET_BACKEND_TYPE_VHOST)) { - virReportError(VIR_ERR_CONFIG_UNSUPPORTED, - "%s", _("vhost-net was requested for an interface, " - "but is unavailable")); - return -1; + /* If the config says explicitly to use vhost and we couldn't open it, + * report an error. + */ + if (vhostfd[i] < 0 && + net->driver.virtio.name == VIR_DOMAIN_NET_BACKEND_TYPE_VHOST) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + "%s", _("vhost-net was requested for an interface, " + "but is unavailable")); + goto error; + } } return 0; + +error: + while (i--) + VIR_FORCE_CLOSE(vhostfd[i]); + + return -1; } int @@ -6477,10 +6504,11 @@ qemuBuildInterfaceCommandLine(virCommandPtr cmd, /* Attempt to use vhost-net mode for these types of network device */ int vhostfd; + int vhostfdSize = 1; - if (qemuOpenVhostNet(def, net, qemuCaps, &vhostfd) < 0) + if (qemuOpenVhostNet(def, net, qemuCaps, &vhostfd, &vhostfdSize) < 0) goto cleanup; - if (vhostfd >= 0) { + if (vhostfdSize > 0) { virCommandTransferFD(cmd, vhostfd); if (virAsprintf(&vhostfdName, "%d", vhostfd) < 0) { virReportOOMError(); diff --git a/src/qemu/qemu_command.h b/src/qemu/qemu_command.h index 6765c3a..c87b754 100644 --- a/src/qemu/qemu_command.h +++ b/src/qemu/qemu_command.h @@ -170,7 +170,8 @@ int qemuPhysIfaceConnect(virDomainDefPtr def, int qemuOpenVhostNet(virDomainDefPtr def, virDomainNetDefPtr net, virQEMUCapsPtr qemuCaps, - int *vhostfd); + int *vhostfd, + int *vhostfdSize); int qemuNetworkPrepareDevices(virDomainDefPtr def); diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index 0a1845a..fdc4b24 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -689,6 +689,7 @@ int qemuDomainAttachNetDevice(virConnectPtr conn, int tapfd = -1; char *vhostfd_name = NULL; int vhostfd = -1; + int vhostfdSize = 0; char *nicstr = NULL; char *netstr = NULL; virNetDevVPortProfilePtr vport = NULL; @@ -738,7 +739,8 @@ int qemuDomainAttachNetDevice(virConnectPtr conn, priv->qemuCaps)) < 0) goto cleanup; iface_connected = true; - if (qemuOpenVhostNet(vm->def, net, priv->qemuCaps, &vhostfd) < 0) + vhostfdSize = 1; + if (qemuOpenVhostNet(vm->def, net, priv->qemuCaps, &vhostfd, &vhostfdSize) < 0) goto cleanup; } else if (actualType == VIR_DOMAIN_NET_TYPE_DIRECT) { if ((tapfd = qemuPhysIfaceConnect(vm->def, driver, net, @@ -746,10 +748,12 @@ int qemuDomainAttachNetDevice(virConnectPtr conn, VIR_NETDEV_VPORT_PROFILE_OP_CREATE)) < 0) goto cleanup; iface_connected = true; - if (qemuOpenVhostNet(vm->def, net, priv->qemuCaps, &vhostfd) < 0) + vhostfdSize = 1; + if (qemuOpenVhostNet(vm->def, net, priv->qemuCaps, &vhostfd, &vhostfdSize) < 0) goto cleanup; } else if (actualType == VIR_DOMAIN_NET_TYPE_ETHERNET) { - if (qemuOpenVhostNet(vm->def, net, priv->qemuCaps, &vhostfd) < 0) + vhostfdSize = 1; + if (qemuOpenVhostNet(vm->def, net, priv->qemuCaps, &vhostfd, &vhostfdSize) < 0) goto cleanup; } @@ -792,7 +796,7 @@ int qemuDomainAttachNetDevice(virConnectPtr conn, goto no_memory; } - if (vhostfd != -1) { + if (vhostfdSize > 0) { if (virAsprintf(&vhostfd_name, "vhostfd-%s", net->info.alias) < 0) goto no_memory; }