diff options
| -rw-r--r-- | MAINTAINERS | 1 | ||||
| -rw-r--r-- | docs/virtio-net-failover.rst | 68 | ||||
| -rw-r--r-- | hw/net/virtio-net.c | 302 | ||||
| -rw-r--r-- | include/hw/virtio/virtio-net.h | 12 | ||||
| -rw-r--r-- | include/hw/virtio/virtio.h | 1 |
5 files changed, 384 insertions, 0 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 325e67a..c958fc7 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1435,6 +1435,7 @@ S: Odd Fixes F: hw/net/ F: include/hw/net/ F: tests/virtio-net-test.c +F: docs/virtio-net-failover.rst T: git https://github.com/jasowang/qemu.git net Parallel NOR Flash devices diff --git a/docs/virtio-net-failover.rst b/docs/virtio-net-failover.rst new file mode 100644 index 0000000..22f64c7 --- /dev/null +++ b/docs/virtio-net-failover.rst @@ -0,0 +1,68 @@ +======================== +QEMU virtio-net standby (net_failover) +======================== + +This document explains the setup and usage of virtio-net standby feature which +is used to create a net_failover pair of devices. + +The general idea is that we have a pair of devices, a (vfio-)pci and a +virtio-net device. Before migration the vfio device is unplugged and data flows +through the virtio-net device, on the target side another vfio-pci device is +plugged in to take over the data-path. In the guest the net_failover kernel +module will pair net devices with the same MAC address. + +The two devices are called primary and standby device. The fast hardware based +networking device is called the primary device and the virtio-net device is the +standby device. + +Restrictions +------------ + +Currently only PCIe devices are allowed as primary devices, this restriction +can be lifted in the future with enhanced QEMU support. Also, only networking +devices are allowed as primary device. The user needs to ensure that primary +and standby devices are not plugged into the same PCIe slot. + +Usecase +------- + + Virtio-net standby allows easy migration while using a passed-through fast + networking device by falling back to a virtio-net device for the duration of + the migration. It is like a simple version of a bond, the difference is that it + requires no configuration in the guest. When a guest is live-migrated to + another host QEMU will unplug the primary device via the PCIe based hotplug + handler and traffic will go through the virtio-net device. On the target + system the primary device will be automatically plugged back and the + net_failover module registers it again as the primary device. + +Usage +----- + + The primary device can be hotplugged or be part of the startup configuration + + -device virtio-net-pci,netdev=hostnet1,id=net1,mac=52:54:00:6f:55:cc, \ + bus=root2,failover=on + + With the parameter failover=on the VIRTIO_NET_F_STANDBY feature will be enabled. + + -device vfio-pci,host=5e:00.2,id=hostdev0,bus=root1,failover_pair_id=net1 + + failover_pair_id references the id of the virtio-net standby device. This + is only for pairing the devices within QEMU. The guest kernel module + net_failover will match devices with identical MAC addresses. + +Hotplug +------- + + Both primary and standby device can be hotplugged via the QEMU monitor. Note + that if the virtio-net device is plugged first a warning will be issued that it + couldn't find the primary device. + +Migration +--------- + + A new migration state wait-unplug was added for this feature. If failover primary + devices are present in the configuration, migration will go into this state. + It will wait until the device unplug is completed in the guest and then move into + active state. On the target system the primary devices will be automatically hotplugged + when the feature bit was negotiated for the virtio-net standby device. diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index d3d688a..314f365 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -12,6 +12,7 @@ */ #include "qemu/osdep.h" +#include "qemu/atomic.h" #include "qemu/iov.h" #include "qemu/main-loop.h" #include "qemu/module.h" @@ -21,6 +22,10 @@ #include "net/tap.h" #include "qemu/error-report.h" #include "qemu/timer.h" +#include "qemu/option.h" +#include "qemu/option_int.h" +#include "qemu/config-file.h" +#include "qapi/qmp/qdict.h" #include "hw/virtio/virtio-net.h" #include "net/vhost_net.h" #include "net/announce.h" @@ -28,11 +33,15 @@ #include "qapi/error.h" #include "qapi/qapi-events-net.h" #include "hw/qdev-properties.h" +#include "qapi/qapi-types-migration.h" +#include "qapi/qapi-events-migration.h" #include "hw/virtio/virtio-access.h" #include "migration/misc.h" #include "standard-headers/linux/ethtool.h" #include "sysemu/sysemu.h" #include "trace.h" +#include "monitor/qdev.h" +#include "hw/pci/pci.h" #define VIRTIO_NET_VM_VERSION 11 @@ -746,9 +755,99 @@ static inline uint64_t virtio_net_supported_guest_offloads(VirtIONet *n) return virtio_net_guest_offloads_by_features(vdev->guest_features); } +static void failover_add_primary(VirtIONet *n, Error **errp) +{ + Error *err = NULL; + + n->primary_device_opts = qemu_opts_find(qemu_find_opts("device"), + n->primary_device_id); + if (n->primary_device_opts) { + n->primary_dev = qdev_device_add(n->primary_device_opts, &err); + if (err) { + qemu_opts_del(n->primary_device_opts); + } + if (n->primary_dev) { + n->primary_bus = n->primary_dev->parent_bus; + if (err) { + qdev_unplug(n->primary_dev, &err); + qdev_set_id(n->primary_dev, ""); + + } + } + } else { + error_setg(errp, "Primary device not found"); + error_append_hint(errp, "Virtio-net failover will not work. Make " + "sure primary device has parameter" + " failover_pair_id=<virtio-net-id>\n"); +} + if (err) { + error_propagate(errp, err); + } +} + +static int is_my_primary(void *opaque, QemuOpts *opts, Error **errp) +{ + VirtIONet *n = opaque; + int ret = 0; + + const char *standby_id = qemu_opt_get(opts, "failover_pair_id"); + + if (standby_id != NULL && (g_strcmp0(standby_id, n->netclient_name) == 0)) { + n->primary_device_id = g_strdup(opts->id); + ret = 1; + } + + return ret; +} + +static DeviceState *virtio_net_find_primary(VirtIONet *n, Error **errp) +{ + DeviceState *dev = NULL; + Error *err = NULL; + + if (qemu_opts_foreach(qemu_find_opts("device"), + is_my_primary, n, &err)) { + if (err) { + error_propagate(errp, err); + return NULL; + } + if (n->primary_device_id) { + dev = qdev_find_recursive(sysbus_get_default(), + n->primary_device_id); + } else { + error_setg(errp, "Primary device id not found"); + return NULL; + } + } + return dev; +} + + + +static DeviceState *virtio_connect_failover_devices(VirtIONet *n, + DeviceState *dev, + Error **errp) +{ + DeviceState *prim_dev = NULL; + Error *err = NULL; + + prim_dev = virtio_net_find_primary(n, &err); + if (prim_dev) { + n->primary_device_id = g_strdup(prim_dev->id); + n->primary_device_opts = prim_dev->opts; + } else { + if (err) { + error_propagate(errp, err); + } + } + + return prim_dev; +} + static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features) { VirtIONet *n = VIRTIO_NET(vdev); + Error *err = NULL; int i; if (n->mtu_bypass_backend && @@ -790,6 +889,28 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features) } else { memset(n->vlans, 0xff, MAX_VLAN >> 3); } + + if (virtio_has_feature(features, VIRTIO_NET_F_STANDBY)) { + qapi_event_send_failover_negotiated(n->netclient_name); + atomic_set(&n->primary_should_be_hidden, false); + failover_add_primary(n, &err); + if (err) { + n->primary_dev = virtio_connect_failover_devices(n, n->qdev, &err); + if (err) { + goto out_err; + } + failover_add_primary(n, &err); + if (err) { + goto out_err; + } + } + } + return; + +out_err: + if (err) { + warn_report_err(err); + } } static int virtio_net_handle_rx_mode(VirtIONet *n, uint8_t cmd, @@ -2650,6 +2771,150 @@ void virtio_net_set_netclient_name(VirtIONet *n, const char *name, n->netclient_type = g_strdup(type); } +static bool failover_unplug_primary(VirtIONet *n) +{ + HotplugHandler *hotplug_ctrl; + PCIDevice *pci_dev; + Error *err = NULL; + + hotplug_ctrl = qdev_get_hotplug_handler(n->primary_dev); + if (hotplug_ctrl) { + pci_dev = PCI_DEVICE(n->primary_dev); + pci_dev->partially_hotplugged = true; + hotplug_handler_unplug_request(hotplug_ctrl, n->primary_dev, &err); + if (err) { + error_report_err(err); + return false; + } + } else { + return false; + } + return true; +} + +static bool failover_replug_primary(VirtIONet *n, Error **errp) +{ + HotplugHandler *hotplug_ctrl; + PCIDevice *pdev = PCI_DEVICE(n->primary_dev); + + if (!pdev->partially_hotplugged) { + return true; + } + if (!n->primary_device_opts) { + n->primary_device_opts = qemu_opts_from_qdict( + qemu_find_opts("device"), + n->primary_device_dict, errp); + } + if (n->primary_device_opts) { + if (n->primary_dev) { + n->primary_bus = n->primary_dev->parent_bus; + } + qdev_set_parent_bus(n->primary_dev, n->primary_bus); + n->primary_should_be_hidden = false; + qemu_opt_set_bool(n->primary_device_opts, + "partially_hotplugged", true, errp); + hotplug_ctrl = qdev_get_hotplug_handler(n->primary_dev); + if (hotplug_ctrl) { + hotplug_handler_pre_plug(hotplug_ctrl, n->primary_dev, errp); + hotplug_handler_plug(hotplug_ctrl, n->primary_dev, errp); + } + if (!n->primary_dev) { + error_setg(errp, "virtio_net: couldn't find primary device"); + } + } + return *errp != NULL; +} + +static void virtio_net_handle_migration_primary(VirtIONet *n, + MigrationState *s) +{ + bool should_be_hidden; + Error *err = NULL; + + should_be_hidden = atomic_read(&n->primary_should_be_hidden); + + if (!n->primary_dev) { + n->primary_dev = virtio_connect_failover_devices(n, n->qdev, &err); + if (!n->primary_dev) { + return; + } + } + + if (migration_in_setup(s) && !should_be_hidden && + n->primary_dev) { + if (failover_unplug_primary(n)) { + vmstate_unregister(n->primary_dev, qdev_get_vmsd(n->primary_dev), + n->primary_dev); + qapi_event_send_unplug_primary(n->primary_device_id); + atomic_set(&n->primary_should_be_hidden, true); + } else { + warn_report("couldn't unplug primary device"); + } + } else if (migration_has_failed(s)) { + /* We already unplugged the device let's plugged it back */ + if (!failover_replug_primary(n, &err)) { + if (err) { + error_report_err(err); + } + } + } +} + +static void virtio_net_migration_state_notifier(Notifier *notifier, void *data) +{ + MigrationState *s = data; + VirtIONet *n = container_of(notifier, VirtIONet, migration_state); + virtio_net_handle_migration_primary(n, s); +} + +static int virtio_net_primary_should_be_hidden(DeviceListener *listener, + QemuOpts *device_opts) +{ + VirtIONet *n = container_of(listener, VirtIONet, primary_listener); + bool match_found; + bool hide; + + n->primary_device_dict = qemu_opts_to_qdict(device_opts, + n->primary_device_dict); + if (n->primary_device_dict) { + g_free(n->standby_id); + n->standby_id = g_strdup(qdict_get_try_str(n->primary_device_dict, + "failover_pair_id")); + } + if (device_opts && g_strcmp0(n->standby_id, n->netclient_name) == 0) { + match_found = true; + } else { + match_found = false; + hide = false; + g_free(n->standby_id); + n->primary_device_dict = NULL; + goto out; + } + + n->primary_device_opts = device_opts; + + /* primary_should_be_hidden is set during feature negotiation */ + hide = atomic_read(&n->primary_should_be_hidden); + + if (n->primary_device_dict) { + g_free(n->primary_device_id); + n->primary_device_id = g_strdup(qdict_get_try_str( + n->primary_device_dict, "id")); + if (!n->primary_device_id) { + warn_report("primary_device_id not set"); + } + } + +out: + if (match_found && hide) { + return 1; + } else if (match_found && !hide) { + return 0; + } else { + return -1; + } +} + static void virtio_net_device_realize(DeviceState *dev, Error **errp) { VirtIODevice *vdev = VIRTIO_DEVICE(dev); @@ -2680,6 +2945,16 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp) n->host_features |= (1ULL << VIRTIO_NET_F_SPEED_DUPLEX); } + if (n->failover) { + n->primary_listener.should_be_hidden = + virtio_net_primary_should_be_hidden; + atomic_set(&n->primary_should_be_hidden, true); + device_listener_register(&n->primary_listener); + n->migration_state.notify = virtio_net_migration_state_notifier; + add_migration_state_change_notifier(&n->migration_state); + n->host_features |= (1ULL << VIRTIO_NET_F_STANDBY); + } + virtio_net_set_config_size(n, n->host_features); virtio_init(vdev, "virtio-net", VIRTIO_ID_NET, n->config_size); @@ -2802,6 +3077,13 @@ static void virtio_net_device_unrealize(DeviceState *dev, Error **errp) g_free(n->mac_table.macs); g_free(n->vlans); + if (n->failover) { + g_free(n->primary_device_id); + g_free(n->standby_id); + qobject_unref(n->primary_device_dict); + n->primary_device_dict = NULL; + } + max_queues = n->multiqueue ? n->max_queues : 1; for (i = 0; i < max_queues; i++) { virtio_net_del_queue(n, i); @@ -2839,6 +3121,23 @@ static int virtio_net_pre_save(void *opaque) return 0; } +static bool primary_unplug_pending(void *opaque) +{ + DeviceState *dev = opaque; + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VirtIONet *n = VIRTIO_NET(vdev); + + return n->primary_dev ? n->primary_dev->pending_deleted_event : false; +} + +static bool dev_unplug_pending(void *opaque) +{ + DeviceState *dev = opaque; + VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev); + + return vdc->primary_unplug_pending(dev); +} + static const VMStateDescription vmstate_virtio_net = { .name = "virtio-net", .minimum_version_id = VIRTIO_NET_VM_VERSION, @@ -2848,6 +3147,7 @@ static const VMStateDescription vmstate_virtio_net = { VMSTATE_END_OF_LIST() }, .pre_save = virtio_net_pre_save, + .dev_unplug_pending = dev_unplug_pending, }; static Property virtio_net_properties[] = { @@ -2909,6 +3209,7 @@ static Property virtio_net_properties[] = { true), DEFINE_PROP_INT32("speed", VirtIONet, net_conf.speed, SPEED_UNKNOWN), DEFINE_PROP_STRING("duplex", VirtIONet, net_conf.duplex_str), + DEFINE_PROP_BOOL("failover", VirtIONet, failover, false), DEFINE_PROP_END_OF_LIST(), }; @@ -2934,6 +3235,7 @@ static void virtio_net_class_init(ObjectClass *klass, void *data) vdc->legacy_features |= (0x1 << VIRTIO_NET_F_GSO); vdc->post_load = virtio_net_post_load_virtio; vdc->vmsd = &vmstate_virtio_net_device; + vdc->primary_unplug_pending = primary_unplug_pending; } static const TypeInfo virtio_net_info = { diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h index 07a9319..96c68d4 100644 --- a/include/hw/virtio/virtio-net.h +++ b/include/hw/virtio/virtio-net.h @@ -18,6 +18,7 @@ #include "standard-headers/linux/virtio_net.h" #include "hw/virtio/virtio.h" #include "net/announce.h" +#include "qemu/option_int.h" #define TYPE_VIRTIO_NET "virtio-net-device" #define VIRTIO_NET(obj) \ @@ -43,6 +44,7 @@ typedef struct virtio_net_conf int32_t speed; char *duplex_str; uint8_t duplex; + char *primary_id_str; } virtio_net_conf; /* Coalesced packets type & status */ @@ -187,6 +189,16 @@ struct VirtIONet { AnnounceTimer announce_timer; bool needs_vnet_hdr_swap; bool mtu_bypass_backend; + QemuOpts *primary_device_opts; + QDict *primary_device_dict; + DeviceState *primary_dev; + BusState *primary_bus; + char *primary_device_id; + char *standby_id; + bool primary_should_be_hidden; + bool failover; + DeviceListener primary_listener; + Notifier migration_state; }; void virtio_net_set_netclient_name(VirtIONet *n, const char *name, diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index 60bbc0e..3448d67 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -160,6 +160,7 @@ typedef struct VirtioDeviceClass { */ int (*post_load)(VirtIODevice *vdev); const VMStateDescription *vmsd; + bool (*primary_unplug_pending)(void *opaque); } VirtioDeviceClass; void virtio_instance_init_common(Object *proxy_obj, void *data, |