This commit adds support for the vhost-user interface to the passt
network backend, enabling high-performance, accelerated networking for
guests using passt.
The passt backend can now operate in a vhost-user mode, where it
communicates with the guest's virtio-net device over a socket pair
using the vhost-user protocol. This offloads the datapath from the
main QEMU loop, significantly improving network performance.
The implementation involves:
- Extending NetPasstState to manage the vhost-user connection
state, including the chardev frontend and the vhost_net
instance.
- Adding the full vhost-user connection and event handling logic,
similar to the standalone net/vhost-user.c client.
- Populating the NetClientInfo structure with implementations for
all the required vhost callbacks that were recently refactored
(is_vhost_user, get_vhost_net, save_acked_features, etc).
When the vhost-user=on option is used with -netdev passt, the new
vhost initialization path is taken instead of the standard
stream-based connection.
Signed-off-by: Laurent Vivier <lviv...@redhat.com>
---
net/passt.c | 334 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 334 insertions(+)
diff --git a/net/passt.c b/net/passt.c
index ce194b1e02f0..3c6bc0dfe89f 100644
--- a/net/passt.c
+++ b/net/passt.c
@@ -7,18 +7,75 @@
*/
#include "qemu/osdep.h"
#include <glib/gstdio.h>
+#include "qemu/error-report.h"
#include <gio/gio.h>
#include "net/net.h"
#include "clients.h"
#include "qapi/error.h"
#include "io/net-listener.h"
+#include "chardev/char-fe.h"
+#include "net/vhost_net.h"
+#include "hw/virtio/vhost.h"
+#include "hw/virtio/vhost-user.h"
+#include "standard-headers/linux/virtio_net.h"
#include "stream_data.h"
+#ifdef CONFIG_VHOST_USER
+static const int user_feature_bits[] = {
+ VIRTIO_F_NOTIFY_ON_EMPTY,
+ VIRTIO_F_NOTIFICATION_DATA,
+ VIRTIO_RING_F_INDIRECT_DESC,
+ VIRTIO_RING_F_EVENT_IDX,
+
+ VIRTIO_F_ANY_LAYOUT,
+ VIRTIO_F_VERSION_1,
+ VIRTIO_NET_F_CSUM,
+ VIRTIO_NET_F_GUEST_CSUM,
+ VIRTIO_NET_F_GSO,
+ VIRTIO_NET_F_GUEST_TSO4,
+ VIRTIO_NET_F_GUEST_TSO6,
+ VIRTIO_NET_F_GUEST_ECN,
+ VIRTIO_NET_F_GUEST_UFO,
+ VIRTIO_NET_F_HOST_TSO4,
+ VIRTIO_NET_F_HOST_TSO6,
+ VIRTIO_NET_F_HOST_ECN,
+ VIRTIO_NET_F_HOST_UFO,
+ VIRTIO_NET_F_MRG_RXBUF,
+ VIRTIO_NET_F_MTU,
+ VIRTIO_F_IOMMU_PLATFORM,
+ VIRTIO_F_RING_PACKED,
+ VIRTIO_F_RING_RESET,
+ VIRTIO_F_IN_ORDER,
+ VIRTIO_NET_F_RSS,
+ VIRTIO_NET_F_RSC_EXT,
+ VIRTIO_NET_F_HASH_REPORT,
+ VIRTIO_NET_F_GUEST_USO4,
+ VIRTIO_NET_F_GUEST_USO6,
+ VIRTIO_NET_F_HOST_USO,
+
+ /* This bit implies RARP isn't sent by QEMU out of band */
+ VIRTIO_NET_F_GUEST_ANNOUNCE,
+
+ VIRTIO_NET_F_MQ,
+
+ VHOST_INVALID_FEATURE_BIT
+};
+#endif
+
typedef struct NetPasstState {
NetStreamData data;
GPtrArray *args;
gchar *pidfile;
pid_t pid;
+#ifdef CONFIG_VHOST_USER
+ /* vhost user */
+ VhostUserState *vhost_user;
+ VHostNetState *vhost_net;
+ CharBackend vhost_chr;
+ guint vhost_watch;
+ uint64_t acked_features;
+ bool started;
+#endif
} NetPasstState;
static int net_passt_stream_start(NetPasstState *s, Error **errp);
@@ -27,6 +84,24 @@ static void net_passt_cleanup(NetClientState *nc)
{
NetPasstState *s = DO_UPCAST(NetPasstState, data.nc, nc);
+#ifdef CONFIG_VHOST_USER
+ if (s->vhost_net) {
+ vhost_net_cleanup(s->vhost_net);
+ g_free(s->vhost_net);
+ s->vhost_net = NULL;
+ }
+ if (s->vhost_watch) {
+ g_source_remove(s->vhost_watch);
+ s->vhost_watch = 0;
+ }
+ qemu_chr_fe_deinit(&s->vhost_chr, true);
+ if (s->vhost_user) {
+ vhost_user_cleanup(s->vhost_user);
+ g_free(s->vhost_user);
+ s->vhost_user = NULL;
+ }
+#endif
+
kill(s->pid, SIGTERM);
g_remove(s->pidfile);
g_free(s->pidfile);
@@ -60,11 +135,112 @@ static gboolean net_passt_send(QIOChannel *ioc,
GIOCondition condition,
return G_SOURCE_CONTINUE;
}
+#ifdef CONFIG_VHOST_USER
+static int passt_set_vnet_endianness(NetClientState *nc, bool enable)
+{
+ assert(nc->info->type == NET_CLIENT_DRIVER_PASST);
+
+ return 0;
+}
+
+static bool passt_has_vnet_hdr(NetClientState *nc)
+{
+ NetPasstState *s = DO_UPCAST(NetPasstState, data.nc, nc);
+
+ assert(nc->info->type == NET_CLIENT_DRIVER_PASST);
+
+ return s->vhost_user != NULL;
+}
+
+static bool passt_has_ufo(NetClientState *nc)
+{
+ NetPasstState *s = DO_UPCAST(NetPasstState, data.nc, nc);
+
+ assert(nc->info->type == NET_CLIENT_DRIVER_PASST);
+
+ return s->vhost_user != NULL;
+}
+
+static bool passt_check_peer_type(NetClientState *nc, ObjectClass *oc,
+ Error **errp)
+{
+ NetPasstState *s = DO_UPCAST(NetPasstState, data.nc, nc);
+ const char *driver = object_class_get_name(oc);
+
+ assert(nc->info->type == NET_CLIENT_DRIVER_PASST);
+
+ if (s->vhost_user != NULL) {
+ return true;
+ }
+
+ if (!g_str_has_prefix(driver, "virtio-net-")) {
+ error_setg(errp, "vhost-user requires frontend driver virtio-net-*");
+ return false;
+ }
+
+ return true;
+}
+
+static bool passt_is_vhost_user(NetClientState *nc)
+{
+ NetPasstState *s = DO_UPCAST(NetPasstState, data.nc, nc);
+
+ assert(nc->info->type == NET_CLIENT_DRIVER_PASST);
+
+ return s->vhost_user != NULL;
+}
+
+static struct vhost_net *passt_get_vhost_net(NetClientState *nc)
+{
+ NetPasstState *s = DO_UPCAST(NetPasstState, data.nc, nc);
+
+ assert(nc->info->type == NET_CLIENT_DRIVER_PASST);
+
+ return s->vhost_net;
+}
+
+static uint64_t passt_get_acked_features(NetClientState *nc)
+{
+ NetPasstState *s = DO_UPCAST(NetPasstState, data.nc, nc);
+
+ assert(nc->info->type == NET_CLIENT_DRIVER_PASST);
+
+ return s->acked_features;
+}
+
+static void passt_save_acked_features(NetClientState *nc)
+{
+ NetPasstState *s = DO_UPCAST(NetPasstState, data.nc, nc);
+
+ assert(nc->info->type == NET_CLIENT_DRIVER_PASST);
+
+ if (s->vhost_net) {
+ uint64_t features = vhost_net_get_acked_features(s->vhost_net);
+ if (features) {
+ s->acked_features = features;
+ }
+ }
+}
+#endif
+
static NetClientInfo net_passt_info = {
.type = NET_CLIENT_DRIVER_PASST,
.size = sizeof(NetPasstState),
.receive = net_passt_receive,
.cleanup = net_passt_cleanup,
+#ifdef CONFIG_VHOST_USER
+ .has_vnet_hdr = passt_has_vnet_hdr,
+ .has_ufo = passt_has_ufo,
+ .set_vnet_be = passt_set_vnet_endianness,
+ .set_vnet_le = passt_set_vnet_endianness,
+ .check_peer_type = passt_check_peer_type,
+ .is_vhost_user = passt_is_vhost_user,
+ .get_vhost_net = passt_get_vhost_net,
+ .vhost_feature_bits = user_feature_bits,
+ .get_acked_features = passt_get_acked_features,
+ .save_acked_features = passt_save_acked_features,
+ .max_tx_queue_size = VIRTQUEUE_MAX_SIZE,
+#endif
};
static void net_passt_client_connected(QIOTask *task, gpointer opaque)
@@ -163,13 +339,171 @@ static int net_passt_stream_start(NetPasstState *s,
Error **errp)
return 0;
}
+#ifdef CONFIG_VHOST_USER
+static gboolean passt_vhost_user_watch(void *do_not_use, GIOCondition cond,
+ void *opaque)
+{
+ NetPasstState *s = opaque;
+
+ qemu_chr_fe_disconnect(&s->vhost_chr);
+
+ return G_SOURCE_CONTINUE;
+}
+
+static void passt_vhost_user_event(void *opaque, QEMUChrEvent event);
+
+static void chr_closed_bh(void *opaque)
+{
+ NetPasstState *s = opaque;
+
+ passt_save_acked_features(&s->data.nc);
+
+ net_client_set_link(&(NetClientState *){ &s->data.nc }, 1, false);
+
+ qemu_chr_fe_set_handlers(&s->vhost_chr, NULL, NULL, passt_vhost_user_event,
+ NULL, s, NULL, true);
+}
+
+static void passt_vhost_user_stop(NetPasstState *s)
+{
+ passt_save_acked_features(&s->data.nc);
+ vhost_net_cleanup(s->vhost_net);
+}
+
+static int passt_vhost_user_start(NetPasstState *s, VhostUserState *be)
+{
+ struct vhost_net *net = NULL;
+ VhostNetOptions options;
+
+ options.backend_type = VHOST_BACKEND_TYPE_USER;
+ options.net_backend = &s->data.nc;
+ options.opaque = be;
+ options.busyloop_timeout = 0;
+ options.nvqs = 2;
+
+ net = vhost_net_init(&options);
+ if (!net) {
+ error_report("failed to init passt vhost_net");
+ goto err;
+ }
+
+ if (s->vhost_net) {
+ vhost_net_cleanup(s->vhost_net);
+ g_free(s->vhost_net);
+ }
+ s->vhost_net = net;
+
+ return 0;
+err:
+ if (net) {
+ vhost_net_cleanup(net);
+ g_free(net);
+ }
+ passt_vhost_user_stop(s);
+ return -1;
+}
+
+static void passt_vhost_user_event(void *opaque, QEMUChrEvent event)
+{
+ NetPasstState *s = opaque;
+ Error *err = NULL;
+
+ switch (event) {
+ case CHR_EVENT_OPENED:
+ if (passt_vhost_user_start(s, s->vhost_user) < 0) {
+ qemu_chr_fe_disconnect(&s->vhost_chr);
+ return;
+ }
+ s->vhost_watch = qemu_chr_fe_add_watch(&s->vhost_chr, G_IO_HUP,
+ passt_vhost_user_watch, s);
+ net_client_set_link(&(NetClientState *){ &s->data.nc }, 1, true);
+ s->started = true;
+ break;
+ case CHR_EVENT_CLOSED:
+ if (s->vhost_watch) {
+ AioContext *ctx = qemu_get_current_aio_context();
+
+ g_source_remove(s->vhost_watch);
+ s->vhost_watch = 0;
+ qemu_chr_fe_set_handlers(&s->vhost_chr, NULL, NULL, NULL, NULL,
+ NULL, NULL, false);
+
+ aio_bh_schedule_oneshot(ctx, chr_closed_bh, s);
+ }
+ break;
+ case CHR_EVENT_BREAK:
+ case CHR_EVENT_MUX_IN:
+ case CHR_EVENT_MUX_OUT:
+ /* Ignore */
+ break;
+ }
+
+ if (err) {
+ error_report_err(err);
+ }
+}
+
static int net_passt_vhost_user_init(NetPasstState *s, Error **errp)
+{
+ Chardev *chr;
+ int sv[2];
+
+ if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) {
+ error_setg_errno(errp, errno, "socketpair() failed");
+ return -1;
+ }
+
+ /* connect to passt */
+ qemu_set_info_str(&s->data.nc, "connecting to passt");
+
+ /* create chardev */
+
+ chr = CHARDEV(object_new(TYPE_CHARDEV_SOCKET));
+ if (!chr || qemu_chr_add_client(chr, sv[0]) == -1) {
+ object_unref(OBJECT(chr));
+ error_setg(errp, "Failed to make socket chardev");
+ goto err;
+ }
+
+ s->vhost_user = g_new0(struct VhostUserState, 1);
+ if (!qemu_chr_fe_init(&s->vhost_chr, chr, errp) ||
+ !vhost_user_init(s->vhost_user, &s->vhost_chr, errp)) {
+ goto err;
+ }
+
+ /* start passt */
+ if (net_passt_start_daemon(s, sv[1], errp) == -1) {
+ goto err;
+ }
+
+ do {
+ if (qemu_chr_fe_wait_connected(&s->vhost_chr, errp) < 0) {
+ goto err;
+ }
+
+ qemu_chr_fe_set_handlers(&s->vhost_chr, NULL, NULL,
+ passt_vhost_user_event, NULL, s, NULL,
+ true);
+ } while (!s->started);
+ qemu_set_info_str(&s->data.nc, "vhost-user,connected to pid %d", s->pid);
+
+ close(sv[1]);
+ return 0;
+err:
+ close(sv[0]);
+ close(sv[1]);
+
+ return -1;
+}
+#else
+static int net_passt_vhost_user_init(NetPasstState *s, Error **errp)
{
error_setg(errp, "vhost-user parameter not yet implemented");
return -1;
}
+#endif
static GPtrArray *net_passt_decode_args(const NetDevPasstOptions *passt,
gchar *pidfile, Error **errp)
--
2.49.0
