[mirror_qemu.git] / net / vhost-user.c

/*
 * vhost-user.c
 *
 * Copyright (c) 2013 Virtual Open Systems Sarl.
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 *
 */

#include "qemu/osdep.h"
#include "clients.h"
#include "net/vhost_net.h"
#include "net/vhost-user.h"
#include "hw/virtio/vhost-user.h"
#include "chardev/char-fe.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-net.h"
#include "qemu/config-file.h"
#include "qemu/error-report.h"
#include "qemu/option.h"
#include "trace.h"

typedef struct NetVhostUserState {
    NetClientState nc;
    CharBackend chr; /* only queue index 0 */
    VhostUserState *vhost_user;
    VHostNetState *vhost_net;
    guint watch;
    uint64_t acked_features;
    bool started;
} NetVhostUserState;

VHostNetState *vhost_user_get_vhost_net(NetClientState *nc)
{
    NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
    assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
    return s->vhost_net;
}

uint64_t vhost_user_get_acked_features(NetClientState *nc)
{
    NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
    assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
    return s->acked_features;
}

static void vhost_user_stop(int queues, NetClientState *ncs[])
{
    NetVhostUserState *s;
    int i;

    for (i = 0; i < queues; i++) {
        assert(ncs[i]->info->type == NET_CLIENT_DRIVER_VHOST_USER);

        s = DO_UPCAST(NetVhostUserState, nc, ncs[i]);

        if (s->vhost_net) {
            /* save acked features */
            uint64_t features = vhost_net_get_acked_features(s->vhost_net);
            if (features) {
                s->acked_features = features;
            }
            vhost_net_cleanup(s->vhost_net);
        }
    }
}

static int vhost_user_start(int queues, NetClientState *ncs[],
                            VhostUserState *be)
{
    VhostNetOptions options;
    struct vhost_net *net = NULL;
    NetVhostUserState *s;
    int max_queues;
    int i;

    options.backend_type = VHOST_BACKEND_TYPE_USER;

    for (i = 0; i < queues; i++) {
        assert(ncs[i]->info->type == NET_CLIENT_DRIVER_VHOST_USER);

        s = DO_UPCAST(NetVhostUserState, nc, ncs[i]);

        options.net_backend = ncs[i];
        options.opaque      = be;
        options.busyloop_timeout = 0;
        net = vhost_net_init(&options);
        if (!net) {
            error_report("failed to init vhost_net for queue %d", i);
            goto err;
        }

        if (i == 0) {
            max_queues = vhost_net_get_max_queues(net);
            if (queues > max_queues) {
                error_report("you are asking more queues than supported: %d",
                             max_queues);
                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);
    }
    vhost_user_stop(i, ncs);
    return -1;
}

static ssize_t vhost_user_receive(NetClientState *nc, const uint8_t *buf,
                                  size_t size)
{
    /* In case of RARP (message size is 60) notify backup to send a fake RARP.
       This fake RARP will be sent by backend only for guest
       without GUEST_ANNOUNCE capability.
     */
    if (size == 60) {
        NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
        int r;
        static int display_rarp_failure = 1;
        char mac_addr[6];

        /* extract guest mac address from the RARP message */
        memcpy(mac_addr, &buf[6], 6);

        r = vhost_net_notify_migration_done(s->vhost_net, mac_addr);

        if ((r != 0) && (display_rarp_failure)) {
            fprintf(stderr,
                    "Vhost user backend fails to broadcast fake RARP\n");
            fflush(stderr);
            display_rarp_failure = 0;
        }
    }

    return size;
}

static void net_vhost_user_cleanup(NetClientState *nc)
{
    NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);

    if (s->vhost_net) {
        vhost_net_cleanup(s->vhost_net);
        g_free(s->vhost_net);
        s->vhost_net = NULL;
    }
    if (nc->queue_index == 0) {
        if (s->watch) {
            g_source_remove(s->watch);
            s->watch = 0;
        }
        qemu_chr_fe_deinit(&s->chr, true);
        if (s->vhost_user) {
            vhost_user_cleanup(s->vhost_user);
            g_free(s->vhost_user);
            s->vhost_user = NULL;
        }
    }

    qemu_purge_queued_packets(nc);
}

static int vhost_user_set_vnet_endianness(NetClientState *nc,
                                          bool enable)
{
    /* Nothing to do.  If the server supports
     * VHOST_USER_PROTOCOL_F_CROSS_ENDIAN, it will get the
     * vnet header endianness from there.  If it doesn't, negotiation
     * fails.
     */
    return 0;
}

static bool vhost_user_has_vnet_hdr(NetClientState *nc)
{
    assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);

    return true;
}

static bool vhost_user_has_ufo(NetClientState *nc)
{
    assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);

    return true;
}

static NetClientInfo net_vhost_user_info = {
        .type = NET_CLIENT_DRIVER_VHOST_USER,
        .size = sizeof(NetVhostUserState),
        .receive = vhost_user_receive,
        .cleanup = net_vhost_user_cleanup,
        .has_vnet_hdr = vhost_user_has_vnet_hdr,
        .has_ufo = vhost_user_has_ufo,
        .set_vnet_be = vhost_user_set_vnet_endianness,
        .set_vnet_le = vhost_user_set_vnet_endianness,
};

static gboolean net_vhost_user_watch(GIOChannel *chan, GIOCondition cond,
                                           void *opaque)
{
    NetVhostUserState *s = opaque;

    qemu_chr_fe_disconnect(&s->chr);

    return TRUE;
}

static void net_vhost_user_event(void *opaque, QEMUChrEvent event);

static void chr_closed_bh(void *opaque)
{
    const char *name = opaque;
    NetClientState *ncs[MAX_QUEUE_NUM];
    NetVhostUserState *s;
    Error *err = NULL;
    int queues;

    queues = qemu_find_net_clients_except(name, ncs,
                                          NET_CLIENT_DRIVER_NIC,
                                          MAX_QUEUE_NUM);
    assert(queues < MAX_QUEUE_NUM);

    s = DO_UPCAST(NetVhostUserState, nc, ncs[0]);

    if (s->vhost_net) {
        s->acked_features = vhost_net_get_acked_features(s->vhost_net);
    }

    qmp_set_link(name, false, &err);

    qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, net_vhost_user_event,
                             NULL, opaque, NULL, true);

    if (err) {
        error_report_err(err);
    }
}

static void net_vhost_user_event(void *opaque, QEMUChrEvent event)
{
    const char *name = opaque;
    NetClientState *ncs[MAX_QUEUE_NUM];
    NetVhostUserState *s;
    Chardev *chr;
    Error *err = NULL;
    int queues;

    queues = qemu_find_net_clients_except(name, ncs,
                                          NET_CLIENT_DRIVER_NIC,
                                          MAX_QUEUE_NUM);
    assert(queues < MAX_QUEUE_NUM);

    s = DO_UPCAST(NetVhostUserState, nc, ncs[0]);
    chr = qemu_chr_fe_get_driver(&s->chr);
    trace_vhost_user_event(chr->label, event);
    switch (event) {
    case CHR_EVENT_OPENED:
        if (vhost_user_start(queues, ncs, s->vhost_user) < 0) {
            qemu_chr_fe_disconnect(&s->chr);
            return;
        }
        s->watch = qemu_chr_fe_add_watch(&s->chr, G_IO_HUP,
                                         net_vhost_user_watch, s);
        qmp_set_link(name, true, &err);
        s->started = true;
        break;
    case CHR_EVENT_CLOSED:
        /* a close event may happen during a read/write, but vhost
         * code assumes the vhost_dev remains setup, so delay the
         * stop & clear to idle.
         * FIXME: better handle failure in vhost code, remove bh
         */
        if (s->watch) {
            AioContext *ctx = qemu_get_current_aio_context();

            g_source_remove(s->watch);
            s->watch = 0;
            qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, NULL, NULL,
                                     NULL, NULL, false);

            aio_bh_schedule_oneshot(ctx, chr_closed_bh, opaque);
        }
        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_vhost_user_init(NetClientState *peer, const char *device,
                               const char *name, Chardev *chr,
                               int queues)
{
    Error *err = NULL;
    NetClientState *nc, *nc0 = NULL;
    NetVhostUserState *s = NULL;
    VhostUserState *user;
    int i;

    assert(name);
    assert(queues > 0);

    user = g_new0(struct VhostUserState, 1);
    for (i = 0; i < queues; i++) {
        nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
        snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
                 i, chr->label);
        nc->queue_index = i;
        if (!nc0) {
            nc0 = nc;
            s = DO_UPCAST(NetVhostUserState, nc, nc);
            if (!qemu_chr_fe_init(&s->chr, chr, &err) ||
                !vhost_user_init(user, &s->chr, &err)) {
                error_report_err(err);
                goto err;
            }
        }
        s = DO_UPCAST(NetVhostUserState, nc, nc);
        s->vhost_user = user;
    }

    s = DO_UPCAST(NetVhostUserState, nc, nc0);
    do {
        if (qemu_chr_fe_wait_connected(&s->chr, &err) < 0) {
            error_report_err(err);
            goto err;
        }
        qemu_chr_fe_set_handlers(&s->chr, NULL, NULL,
                                 net_vhost_user_event, NULL, nc0->name, NULL,
                                 true);
    } while (!s->started);

    assert(s->vhost_net);

    return 0;

err:
    if (user) {
        vhost_user_cleanup(user);
        g_free(user);
        if (s) {
            s->vhost_user = NULL;
        }
    }
    if (nc0) {
        qemu_del_net_client(nc0);
    }

    return -1;
}

static Chardev *net_vhost_claim_chardev(
    const NetdevVhostUserOptions *opts, Error **errp)
{
    Chardev *chr = qemu_chr_find(opts->chardev);

    if (chr == NULL) {
        error_setg(errp, "chardev \"%s\" not found", opts->chardev);
        return NULL;
    }

    if (!qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_RECONNECTABLE)) {
        error_setg(errp, "chardev \"%s\" is not reconnectable",
                   opts->chardev);
        return NULL;
    }
    if (!qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_FD_PASS)) {
        error_setg(errp, "chardev \"%s\" does not support FD passing",
                   opts->chardev);
        return NULL;
    }

    return chr;
}

static int net_vhost_check_net(void *opaque, QemuOpts *opts, Error **errp)
{
    const char *name = opaque;
    const char *driver, *netdev;

    driver = qemu_opt_get(opts, "driver");
    netdev = qemu_opt_get(opts, "netdev");

    if (!driver || !netdev) {
        return 0;
    }

    if (strcmp(netdev, name) == 0 &&
        !g_str_has_prefix(driver, "virtio-net-")) {
        error_setg(errp, "vhost-user requires frontend driver virtio-net-*");
        return -1;
    }

    return 0;
}

int net_init_vhost_user(const Netdev *netdev, const char *name,
                        NetClientState *peer, Error **errp)
{
    int queues;
    const NetdevVhostUserOptions *vhost_user_opts;
    Chardev *chr;

    assert(netdev->type == NET_CLIENT_DRIVER_VHOST_USER);
    vhost_user_opts = &netdev->u.vhost_user;

    chr = net_vhost_claim_chardev(vhost_user_opts, errp);
    if (!chr) {
        return -1;
    }

    /* verify net frontend */
    if (qemu_opts_foreach(qemu_find_opts("device"), net_vhost_check_net,
                          (char *)name, errp)) {
        return -1;
    }

    queues = vhost_user_opts->has_queues ? vhost_user_opts->queues : 1;
    if (queues < 1 || queues > MAX_QUEUE_NUM) {
        error_setg(errp,
                   "vhost-user number of queues must be in range [1, %d]",
                   MAX_QUEUE_NUM);
        return -1;
    }

    return net_vhost_user_init(peer, "vhost_user", name, chr, queues);
}
Commit	Line	Data
	1	/*
	2	* vhost-user.c
	3	*
	4	* Copyright (c) 2013 Virtual Open Systems Sarl.
	5	*
	6	* This work is licensed under the terms of the GNU GPL, version 2 or later.
	7	* See the COPYING file in the top-level directory.
	8	*
	9	*/
	10
	11	#include "qemu/osdep.h"
	12	#include "clients.h"
	13	#include "net/vhost_net.h"
	14	#include "net/vhost-user.h"
	15	#include "hw/virtio/vhost-user.h"
	16	#include "chardev/char-fe.h"
	17	#include "qapi/error.h"
	18	#include "qapi/qapi-commands-net.h"
	19	#include "qemu/config-file.h"
	20	#include "qemu/error-report.h"
	21	#include "qemu/option.h"
	22	#include "trace.h"
	23
	24	typedef struct NetVhostUserState {
	25	NetClientState nc;
	26	CharBackend chr; /* only queue index 0 */
	27	VhostUserState *vhost_user;
	28	VHostNetState *vhost_net;
	29	guint watch;
	30	uint64_t acked_features;
	31	bool started;
	32	} NetVhostUserState;
	33
	34	VHostNetState vhost_user_get_vhost_net(NetClientState nc)
	35	{
	36	NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
	37	assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
	38	return s->vhost_net;
	39	}
	40
	41	uint64_t vhost_user_get_acked_features(NetClientState *nc)
	42	{
	43	NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
	44	assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
	45	return s->acked_features;
	46	}
	47
	48	static void vhost_user_stop(int queues, NetClientState *ncs[])
	49	{
	50	NetVhostUserState *s;
	51	int i;
	52
	53	for (i = 0; i < queues; i++) {
	54	assert(ncs[i]->info->type == NET_CLIENT_DRIVER_VHOST_USER);
	55
	56	s = DO_UPCAST(NetVhostUserState, nc, ncs[i]);
	57
	58	if (s->vhost_net) {
	59	/* save acked features */
	60	uint64_t features = vhost_net_get_acked_features(s->vhost_net);
	61	if (features) {
	62	s->acked_features = features;
	63	}
	64	vhost_net_cleanup(s->vhost_net);
	65	}
	66	}
	67	}
	68
	69	static int vhost_user_start(int queues, NetClientState *ncs[],
	70	VhostUserState *be)
	71	{
	72	VhostNetOptions options;
	73	struct vhost_net *net = NULL;
	74	NetVhostUserState *s;
	75	int max_queues;
	76	int i;
	77
	78	options.backend_type = VHOST_BACKEND_TYPE_USER;
	79
	80	for (i = 0; i < queues; i++) {
	81	assert(ncs[i]->info->type == NET_CLIENT_DRIVER_VHOST_USER);
	82
	83	s = DO_UPCAST(NetVhostUserState, nc, ncs[i]);
	84
	85	options.net_backend = ncs[i];
	86	options.opaque = be;
	87	options.busyloop_timeout = 0;
	88	net = vhost_net_init(&options);
	89	if (!net) {
	90	error_report("failed to init vhost_net for queue %d", i);
	91	goto err;
	92	}
	93
	94	if (i == 0) {
	95	max_queues = vhost_net_get_max_queues(net);
	96	if (queues > max_queues) {
	97	error_report("you are asking more queues than supported: %d",
	98	max_queues);
	99	goto err;
	100	}
	101	}
	102
	103	if (s->vhost_net) {
	104	vhost_net_cleanup(s->vhost_net);
	105	g_free(s->vhost_net);
	106	}
	107	s->vhost_net = net;
	108	}
	109
	110	return 0;
	111
	112	err:
	113	if (net) {
	114	vhost_net_cleanup(net);
	115	g_free(net);
	116	}
	117	vhost_user_stop(i, ncs);
	118	return -1;
	119	}
	120
	121	static ssize_t vhost_user_receive(NetClientState nc, const uint8_t buf,
	122	size_t size)
	123	{
	124	/* In case of RARP (message size is 60) notify backup to send a fake RARP.
	125	This fake RARP will be sent by backend only for guest
	126	without GUEST_ANNOUNCE capability.
	127	*/
	128	if (size == 60) {
	129	NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
	130	int r;
	131	static int display_rarp_failure = 1;
	132	char mac_addr[6];
	133
	134	/* extract guest mac address from the RARP message */
	135	memcpy(mac_addr, &buf[6], 6);
	136
	137	r = vhost_net_notify_migration_done(s->vhost_net, mac_addr);
	138
	139	if ((r != 0) && (display_rarp_failure)) {
	140	fprintf(stderr,
	141	"Vhost user backend fails to broadcast fake RARP\n");
	142	fflush(stderr);
	143	display_rarp_failure = 0;
	144	}
	145	}
	146
	147	return size;
	148	}
	149
	150	static void net_vhost_user_cleanup(NetClientState *nc)
	151	{
	152	NetVhostUserState *s = DO_UPCAST(NetVhostUserState, nc, nc);
	153
	154	if (s->vhost_net) {
	155	vhost_net_cleanup(s->vhost_net);
	156	g_free(s->vhost_net);
	157	s->vhost_net = NULL;
	158	}
	159	if (nc->queue_index == 0) {
	160	if (s->watch) {
	161	g_source_remove(s->watch);
	162	s->watch = 0;
	163	}
	164	qemu_chr_fe_deinit(&s->chr, true);
	165	if (s->vhost_user) {
	166	vhost_user_cleanup(s->vhost_user);
	167	g_free(s->vhost_user);
	168	s->vhost_user = NULL;
	169	}
	170	}
	171
	172	qemu_purge_queued_packets(nc);
	173	}
	174
	175	static int vhost_user_set_vnet_endianness(NetClientState *nc,
	176	bool enable)
	177	{
	178	/* Nothing to do. If the server supports
	179	* VHOST_USER_PROTOCOL_F_CROSS_ENDIAN, it will get the
	180	* vnet header endianness from there. If it doesn't, negotiation
	181	* fails.
	182	*/
	183	return 0;
	184	}
	185
	186	static bool vhost_user_has_vnet_hdr(NetClientState *nc)
	187	{
	188	assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
	189
	190	return true;
	191	}
	192
	193	static bool vhost_user_has_ufo(NetClientState *nc)
	194	{
	195	assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
	196
	197	return true;
	198	}
	199
	200	static NetClientInfo net_vhost_user_info = {
	201	.type = NET_CLIENT_DRIVER_VHOST_USER,
	202	.size = sizeof(NetVhostUserState),
	203	.receive = vhost_user_receive,
	204	.cleanup = net_vhost_user_cleanup,
	205	.has_vnet_hdr = vhost_user_has_vnet_hdr,
	206	.has_ufo = vhost_user_has_ufo,
	207	.set_vnet_be = vhost_user_set_vnet_endianness,
	208	.set_vnet_le = vhost_user_set_vnet_endianness,
	209	};
	210
	211	static gboolean net_vhost_user_watch(GIOChannel *chan, GIOCondition cond,
	212	void *opaque)
	213	{
	214	NetVhostUserState *s = opaque;
	215
	216	qemu_chr_fe_disconnect(&s->chr);
	217
	218	return TRUE;
	219	}
	220
	221	static void net_vhost_user_event(void *opaque, QEMUChrEvent event);
	222
	223	static void chr_closed_bh(void *opaque)
	224	{
	225	const char *name = opaque;
	226	NetClientState *ncs[MAX_QUEUE_NUM];
	227	NetVhostUserState *s;
	228	Error *err = NULL;
	229	int queues;
	230
	231	queues = qemu_find_net_clients_except(name, ncs,
	232	NET_CLIENT_DRIVER_NIC,
	233	MAX_QUEUE_NUM);
	234	assert(queues < MAX_QUEUE_NUM);
	235
	236	s = DO_UPCAST(NetVhostUserState, nc, ncs[0]);
	237
	238	if (s->vhost_net) {
	239	s->acked_features = vhost_net_get_acked_features(s->vhost_net);
	240	}
	241
	242	qmp_set_link(name, false, &err);
	243
	244	qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, net_vhost_user_event,
	245	NULL, opaque, NULL, true);
	246
	247	if (err) {
	248	error_report_err(err);
	249	}
	250	}
	251
	252	static void net_vhost_user_event(void *opaque, QEMUChrEvent event)
	253	{
	254	const char *name = opaque;
	255	NetClientState *ncs[MAX_QUEUE_NUM];
	256	NetVhostUserState *s;
	257	Chardev *chr;
	258	Error *err = NULL;
	259	int queues;
	260
	261	queues = qemu_find_net_clients_except(name, ncs,
	262	NET_CLIENT_DRIVER_NIC,
	263	MAX_QUEUE_NUM);
	264	assert(queues < MAX_QUEUE_NUM);
	265
	266	s = DO_UPCAST(NetVhostUserState, nc, ncs[0]);
	267	chr = qemu_chr_fe_get_driver(&s->chr);
	268	trace_vhost_user_event(chr->label, event);
	269	switch (event) {
	270	case CHR_EVENT_OPENED:
	271	if (vhost_user_start(queues, ncs, s->vhost_user) < 0) {
	272	qemu_chr_fe_disconnect(&s->chr);
	273	return;
	274	}
	275	s->watch = qemu_chr_fe_add_watch(&s->chr, G_IO_HUP,
	276	net_vhost_user_watch, s);
	277	qmp_set_link(name, true, &err);
	278	s->started = true;
	279	break;
	280	case CHR_EVENT_CLOSED:
	281	/* a close event may happen during a read/write, but vhost
	282	* code assumes the vhost_dev remains setup, so delay the
	283	* stop & clear to idle.
	284	* FIXME: better handle failure in vhost code, remove bh
	285	*/
	286	if (s->watch) {
	287	AioContext *ctx = qemu_get_current_aio_context();
	288
	289	g_source_remove(s->watch);
	290	s->watch = 0;
	291	qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, NULL, NULL,
	292	NULL, NULL, false);
	293
	294	aio_bh_schedule_oneshot(ctx, chr_closed_bh, opaque);
	295	}
	296	break;
	297	case CHR_EVENT_BREAK:
	298	case CHR_EVENT_MUX_IN:
	299	case CHR_EVENT_MUX_OUT:
	300	/* Ignore */
	301	break;
	302	}
	303
	304	if (err) {
	305	error_report_err(err);
	306	}
	307	}
	308
	309	static int net_vhost_user_init(NetClientState peer, const char device,
	310	const char name, Chardev chr,
	311	int queues)
	312	{
	313	Error *err = NULL;
	314	NetClientState nc, nc0 = NULL;
	315	NetVhostUserState *s = NULL;
	316	VhostUserState *user;
	317	int i;
	318
	319	assert(name);
	320	assert(queues > 0);
	321
	322	user = g_new0(struct VhostUserState, 1);
	323	for (i = 0; i < queues; i++) {
	324	nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
	325	snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
	326	i, chr->label);
	327	nc->queue_index = i;
	328	if (!nc0) {
	329	nc0 = nc;
	330	s = DO_UPCAST(NetVhostUserState, nc, nc);
	331	if (!qemu_chr_fe_init(&s->chr, chr, &err) \|\|
	332	!vhost_user_init(user, &s->chr, &err)) {
	333	error_report_err(err);
	334	goto err;
	335	}
	336	}
	337	s = DO_UPCAST(NetVhostUserState, nc, nc);
	338	s->vhost_user = user;
	339	}
	340
	341	s = DO_UPCAST(NetVhostUserState, nc, nc0);
	342	do {
	343	if (qemu_chr_fe_wait_connected(&s->chr, &err) < 0) {
	344	error_report_err(err);
	345	goto err;
	346	}
	347	qemu_chr_fe_set_handlers(&s->chr, NULL, NULL,
	348	net_vhost_user_event, NULL, nc0->name, NULL,
	349	true);
	350	} while (!s->started);
	351
	352	assert(s->vhost_net);
	353
	354	return 0;
	355
	356	err:
	357	if (user) {
	358	vhost_user_cleanup(user);
	359	g_free(user);
	360	if (s) {
	361	s->vhost_user = NULL;
	362	}
	363	}
	364	if (nc0) {
	365	qemu_del_net_client(nc0);
	366	}
	367
	368	return -1;
	369	}
	370
	371	static Chardev *net_vhost_claim_chardev(
	372	const NetdevVhostUserOptions opts, Error *errp)
	373	{
	374	Chardev *chr = qemu_chr_find(opts->chardev);
	375
	376	if (chr == NULL) {
	377	error_setg(errp, "chardev \"%s\" not found", opts->chardev);
	378	return NULL;
	379	}
	380
	381	if (!qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_RECONNECTABLE)) {
	382	error_setg(errp, "chardev \"%s\" is not reconnectable",
	383	opts->chardev);
	384	return NULL;
	385	}
	386	if (!qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_FD_PASS)) {
	387	error_setg(errp, "chardev \"%s\" does not support FD passing",
	388	opts->chardev);
	389	return NULL;
	390	}
	391
	392	return chr;
	393	}
	394
	395	static int net_vhost_check_net(void opaque, QemuOpts opts, Error **errp)
	396	{
	397	const char *name = opaque;
	398	const char driver, netdev;
	399
	400	driver = qemu_opt_get(opts, "driver");
	401	netdev = qemu_opt_get(opts, "netdev");
	402
	403	if (!driver \|\| !netdev) {
	404	return 0;
	405	}
	406
	407	if (strcmp(netdev, name) == 0 &&
	408	!g_str_has_prefix(driver, "virtio-net-")) {
	409	error_setg(errp, "vhost-user requires frontend driver virtio-net-*");
	410	return -1;
	411	}
	412
	413	return 0;
	414	}
	415
	416	int net_init_vhost_user(const Netdev netdev, const char name,
	417	NetClientState peer, Error *errp)
	418	{
	419	int queues;
	420	const NetdevVhostUserOptions *vhost_user_opts;
	421	Chardev *chr;
	422
	423	assert(netdev->type == NET_CLIENT_DRIVER_VHOST_USER);
	424	vhost_user_opts = &netdev->u.vhost_user;
	425
	426	chr = net_vhost_claim_chardev(vhost_user_opts, errp);
	427	if (!chr) {
	428	return -1;
	429	}
	430
	431	/* verify net frontend */
	432	if (qemu_opts_foreach(qemu_find_opts("device"), net_vhost_check_net,
	433	(char *)name, errp)) {
	434	return -1;
	435	}
	436
	437	queues = vhost_user_opts->has_queues ? vhost_user_opts->queues : 1;
	438	if (queues < 1 \|\| queues > MAX_QUEUE_NUM) {
	439	error_setg(errp,
	440	"vhost-user number of queues must be in range [1, %d]",
	441	MAX_QUEUE_NUM);
	442	return -1;
	443	}
	444
	445	return net_vhost_user_init(peer, "vhost_user", name, chr, queues);
	446	}