[mirror_qemu.git] / util / vhost-user-server.c

/*
 * Sharing QEMU devices via vhost-user protocol
 *
 * Copyright (c) Coiby Xu <coiby.xu@gmail.com>.
 * Copyright (c) 2020 Red Hat, Inc.
 *
 * 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 "qemu/error-report.h"
#include "qemu/main-loop.h"
#include "qemu/vhost-user-server.h"
#include "block/aio-wait.h"

/*
 * Theory of operation:
 *
 * VuServer is started and stopped by vhost_user_server_start() and
 * vhost_user_server_stop() from the main loop thread. Starting the server
 * opens a vhost-user UNIX domain socket and listens for incoming connections.
 * Only one connection is allowed at a time.
 *
 * The connection is handled by the vu_client_trip() coroutine in the
 * VuServer->ctx AioContext. The coroutine consists of a vu_dispatch() loop
 * where libvhost-user calls vu_message_read() to receive the next vhost-user
 * protocol messages over the UNIX domain socket.
 *
 * When virtqueues are set up libvhost-user calls set_watch() to monitor kick
 * fds. These fds are also handled in the VuServer->ctx AioContext.
 *
 * Both vu_client_trip() and kick fd monitoring can be stopped by shutting down
 * the socket connection. Shutting down the socket connection causes
 * vu_message_read() to fail since no more data can be received from the socket.
 * After vu_dispatch() fails, vu_client_trip() calls vu_deinit() to stop
 * libvhost-user before terminating the coroutine. vu_deinit() calls
 * remove_watch() to stop monitoring kick fds and this stops virtqueue
 * processing.
 *
 * When vu_client_trip() has finished cleaning up it schedules a BH in the main
 * loop thread to accept the next client connection.
 *
 * When libvhost-user detects an error it calls panic_cb() and sets the
 * dev->broken flag. Both vu_client_trip() and kick fd processing stop when
 * the dev->broken flag is set.
 *
 * It is possible to switch AioContexts using
 * vhost_user_server_detach_aio_context() and
 * vhost_user_server_attach_aio_context(). They stop monitoring fds in the old
 * AioContext and resume monitoring in the new AioContext. The vu_client_trip()
 * coroutine remains in a yielded state during the switch. This is made
 * possible by QIOChannel's support for spurious coroutine re-entry in
 * qio_channel_yield(). The coroutine will restart I/O when re-entered from the
 * new AioContext.
 */

static void vmsg_close_fds(VhostUserMsg *vmsg)
{
    int i;
    for (i = 0; i < vmsg->fd_num; i++) {
        close(vmsg->fds[i]);
    }
}

static void vmsg_unblock_fds(VhostUserMsg *vmsg)
{
    int i;
    for (i = 0; i < vmsg->fd_num; i++) {
        qemu_socket_set_nonblock(vmsg->fds[i]);
    }
}

static void panic_cb(VuDev *vu_dev, const char *buf)
{
    error_report("vu_panic: %s", buf);
}

void vhost_user_server_inc_in_flight(VuServer *server)
{
    assert(!server->wait_idle);
    qatomic_inc(&server->in_flight);
}

void vhost_user_server_dec_in_flight(VuServer *server)
{
    if (qatomic_fetch_dec(&server->in_flight) == 1) {
        if (server->wait_idle) {
            aio_co_wake(server->co_trip);
        }
    }
}

bool vhost_user_server_has_in_flight(VuServer *server)
{
    return qatomic_load_acquire(&server->in_flight) > 0;
}

static bool coroutine_fn
vu_message_read(VuDev *vu_dev, int conn_fd, VhostUserMsg *vmsg)
{
    struct iovec iov = {
        .iov_base = (char *)vmsg,
        .iov_len = VHOST_USER_HDR_SIZE,
    };
    int rc, read_bytes = 0;
    Error *local_err = NULL;
    const size_t max_fds = G_N_ELEMENTS(vmsg->fds);
    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
    QIOChannel *ioc = server->ioc;

    vmsg->fd_num = 0;
    if (!ioc) {
        error_report_err(local_err);
        goto fail;
    }

    assert(qemu_in_coroutine());
    do {
        size_t nfds = 0;
        int *fds = NULL;

        /*
         * qio_channel_readv_full may have short reads, keeping calling it
         * until getting VHOST_USER_HDR_SIZE or 0 bytes in total
         */
        rc = qio_channel_readv_full(ioc, &iov, 1, &fds, &nfds, 0, &local_err);
        if (rc < 0) {
            if (rc == QIO_CHANNEL_ERR_BLOCK) {
                assert(local_err == NULL);
                if (server->ctx) {
                    server->in_qio_channel_yield = true;
                    qio_channel_yield(ioc, G_IO_IN);
                    server->in_qio_channel_yield = false;
                } else {
                    /* Wait until attached to an AioContext again */
                    qemu_coroutine_yield();
                }
                continue;
            } else {
                error_report_err(local_err);
                goto fail;
            }
        }

        if (nfds > 0) {
            if (vmsg->fd_num + nfds > max_fds) {
                error_report("A maximum of %zu fds are allowed, "
                             "however got %zu fds now",
                             max_fds, vmsg->fd_num + nfds);
                g_free(fds);
                goto fail;
            }
            memcpy(vmsg->fds + vmsg->fd_num, fds, nfds * sizeof(vmsg->fds[0]));
            vmsg->fd_num += nfds;
            g_free(fds);
        }

        if (rc == 0) { /* socket closed */
            goto fail;
        }

        iov.iov_base += rc;
        iov.iov_len -= rc;
        read_bytes += rc;
    } while (read_bytes != VHOST_USER_HDR_SIZE);

    /* qio_channel_readv_full will make socket fds blocking, unblock them */
    vmsg_unblock_fds(vmsg);
    if (vmsg->size > sizeof(vmsg->payload)) {
        error_report("Error: too big message request: %d, "
                     "size: vmsg->size: %u, "
                     "while sizeof(vmsg->payload) = %zu",
                     vmsg->request, vmsg->size, sizeof(vmsg->payload));
        goto fail;
    }

    struct iovec iov_payload = {
        .iov_base = (char *)&vmsg->payload,
        .iov_len = vmsg->size,
    };
    if (vmsg->size) {
        rc = qio_channel_readv_all_eof(ioc, &iov_payload, 1, &local_err);
        if (rc != 1) {
            if (local_err) {
                error_report_err(local_err);
            }
            goto fail;
        }
    }

    return true;

fail:
    vmsg_close_fds(vmsg);

    return false;
}

static coroutine_fn void vu_client_trip(void *opaque)
{
    VuServer *server = opaque;
    VuDev *vu_dev = &server->vu_dev;

    while (!vu_dev->broken && vu_dispatch(vu_dev)) {
        /* Keep running */
    }

    if (vhost_user_server_has_in_flight(server)) {
        /* Wait for requests to complete before we can unmap the memory */
        server->wait_idle = true;
        qemu_coroutine_yield();
        server->wait_idle = false;
    }
    assert(!vhost_user_server_has_in_flight(server));

    vu_deinit(vu_dev);

    /* vu_deinit() should have called remove_watch() */
    assert(QTAILQ_EMPTY(&server->vu_fd_watches));

    object_unref(OBJECT(server->sioc));
    server->sioc = NULL;

    object_unref(OBJECT(server->ioc));
    server->ioc = NULL;

    server->co_trip = NULL;
    if (server->restart_listener_bh) {
        qemu_bh_schedule(server->restart_listener_bh);
    }
    aio_wait_kick();
}

/*
 * a wrapper for vu_kick_cb
 *
 * since aio_dispatch can only pass one user data pointer to the
 * callback function, pack VuDev and pvt into a struct. Then unpack it
 * and pass them to vu_kick_cb
 */
static void kick_handler(void *opaque)
{
    VuFdWatch *vu_fd_watch = opaque;
    VuDev *vu_dev = vu_fd_watch->vu_dev;

    vu_fd_watch->cb(vu_dev, 0, vu_fd_watch->pvt);

    /* Stop vu_client_trip() if an error occurred in vu_fd_watch->cb() */
    if (vu_dev->broken) {
        VuServer *server = container_of(vu_dev, VuServer, vu_dev);

        qio_channel_shutdown(server->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
    }
}

static VuFdWatch *find_vu_fd_watch(VuServer *server, int fd)
{

    VuFdWatch *vu_fd_watch, *next;
    QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
        if (vu_fd_watch->fd == fd) {
            return vu_fd_watch;
        }
    }
    return NULL;
}

static void
set_watch(VuDev *vu_dev, int fd, int vu_evt,
          vu_watch_cb cb, void *pvt)
{

    VuServer *server = container_of(vu_dev, VuServer, vu_dev);
    g_assert(vu_dev);
    g_assert(fd >= 0);
    g_assert(cb);

    VuFdWatch *vu_fd_watch = find_vu_fd_watch(server, fd);

    if (!vu_fd_watch) {
        VuFdWatch *vu_fd_watch = g_new0(VuFdWatch, 1);

        QTAILQ_INSERT_TAIL(&server->vu_fd_watches, vu_fd_watch, next);

        vu_fd_watch->fd = fd;
        vu_fd_watch->cb = cb;
        qemu_socket_set_nonblock(fd);
        aio_set_fd_handler(server->ctx, fd, kick_handler,
                           NULL, NULL, NULL, vu_fd_watch);
        vu_fd_watch->vu_dev = vu_dev;
        vu_fd_watch->pvt = pvt;
    }
}


static void remove_watch(VuDev *vu_dev, int fd)
{
    VuServer *server;
    g_assert(vu_dev);
    g_assert(fd >= 0);

    server = container_of(vu_dev, VuServer, vu_dev);

    VuFdWatch *vu_fd_watch = find_vu_fd_watch(server, fd);

    if (!vu_fd_watch) {
        return;
    }
    aio_set_fd_handler(server->ctx, fd, NULL, NULL, NULL, NULL, NULL);

    QTAILQ_REMOVE(&server->vu_fd_watches, vu_fd_watch, next);
    g_free(vu_fd_watch);
}


static void vu_accept(QIONetListener *listener, QIOChannelSocket *sioc,
                      gpointer opaque)
{
    VuServer *server = opaque;

    if (server->sioc) {
        warn_report("Only one vhost-user client is allowed to "
                    "connect the server one time");
        return;
    }

    if (!vu_init(&server->vu_dev, server->max_queues, sioc->fd, panic_cb,
                 vu_message_read, set_watch, remove_watch, server->vu_iface)) {
        error_report("Failed to initialize libvhost-user");
        return;
    }

    /*
     * Unset the callback function for network listener to make another
     * vhost-user client keeping waiting until this client disconnects
     */
    qio_net_listener_set_client_func(server->listener,
                                     NULL,
                                     NULL,
                                     NULL);
    server->sioc = sioc;
    /*
     * Increase the object reference, so sioc will not freed by
     * qio_net_listener_channel_func which will call object_unref(OBJECT(sioc))
     */
    object_ref(OBJECT(server->sioc));
    qio_channel_set_name(QIO_CHANNEL(sioc), "vhost-user client");
    server->ioc = QIO_CHANNEL(sioc);
    object_ref(OBJECT(server->ioc));

    /* TODO vu_message_write() spins if non-blocking! */
    qio_channel_set_blocking(server->ioc, false, NULL);

    qio_channel_set_follow_coroutine_ctx(server->ioc, true);

    server->co_trip = qemu_coroutine_create(vu_client_trip, server);

    aio_context_acquire(server->ctx);
    vhost_user_server_attach_aio_context(server, server->ctx);
    aio_context_release(server->ctx);
}

/* server->ctx acquired by caller */
void vhost_user_server_stop(VuServer *server)
{
    qemu_bh_delete(server->restart_listener_bh);
    server->restart_listener_bh = NULL;

    if (server->sioc) {
        VuFdWatch *vu_fd_watch;

        QTAILQ_FOREACH(vu_fd_watch, &server->vu_fd_watches, next) {
            aio_set_fd_handler(server->ctx, vu_fd_watch->fd,
                               NULL, NULL, NULL, NULL, vu_fd_watch);
        }

        qio_channel_shutdown(server->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);

        AIO_WAIT_WHILE(server->ctx, server->co_trip);
    }

    if (server->listener) {
        qio_net_listener_disconnect(server->listener);
        object_unref(OBJECT(server->listener));
    }
}

/*
 * Allow the next client to connect to the server. Called from a BH in the main
 * loop.
 */
static void restart_listener_bh(void *opaque)
{
    VuServer *server = opaque;

    qio_net_listener_set_client_func(server->listener, vu_accept, server,
                                     NULL);
}

/* Called with ctx acquired */
void vhost_user_server_attach_aio_context(VuServer *server, AioContext *ctx)
{
    VuFdWatch *vu_fd_watch;

    server->ctx = ctx;

    if (!server->sioc) {
        return;
    }

    QTAILQ_FOREACH(vu_fd_watch, &server->vu_fd_watches, next) {
        aio_set_fd_handler(ctx, vu_fd_watch->fd, kick_handler, NULL,
                           NULL, NULL, vu_fd_watch);
    }

    assert(!server->in_qio_channel_yield);
    aio_co_schedule(ctx, server->co_trip);
}

/* Called with server->ctx acquired */
void vhost_user_server_detach_aio_context(VuServer *server)
{
    if (server->sioc) {
        VuFdWatch *vu_fd_watch;

        QTAILQ_FOREACH(vu_fd_watch, &server->vu_fd_watches, next) {
            aio_set_fd_handler(server->ctx, vu_fd_watch->fd,
                               NULL, NULL, NULL, NULL, vu_fd_watch);
        }
    }

    server->ctx = NULL;

    if (server->ioc) {
        if (server->in_qio_channel_yield) {
            /* Stop receiving the next vhost-user message */
            qio_channel_wake_read(server->ioc);
        }
    }
}

bool vhost_user_server_start(VuServer *server,
                             SocketAddress *socket_addr,
                             AioContext *ctx,
                             uint16_t max_queues,
                             const VuDevIface *vu_iface,
                             Error **errp)
{
    QEMUBH *bh;
    QIONetListener *listener;

    if (socket_addr->type != SOCKET_ADDRESS_TYPE_UNIX &&
        socket_addr->type != SOCKET_ADDRESS_TYPE_FD) {
        error_setg(errp, "Only socket address types 'unix' and 'fd' are supported");
        return false;
    }

    listener = qio_net_listener_new();
    if (qio_net_listener_open_sync(listener, socket_addr, 1,
                                   errp) < 0) {
        object_unref(OBJECT(listener));
        return false;
    }

    bh = qemu_bh_new(restart_listener_bh, server);

    /* zero out unspecified fields */
    *server = (VuServer) {
        .listener              = listener,
        .restart_listener_bh   = bh,
        .vu_iface              = vu_iface,
        .max_queues            = max_queues,
        .ctx                   = ctx,
    };

    qio_net_listener_set_name(server->listener, "vhost-user-backend-listener");

    qio_net_listener_set_client_func(server->listener,
                                     vu_accept,
                                     server,
                                     NULL);

    QTAILQ_INIT(&server->vu_fd_watches);
    return true;
}
Commit	Line	Data
70eb2c07 CX	1	/*
	2	* Sharing QEMU devices via vhost-user protocol
	3	*
	4	* Copyright (c) Coiby Xu <coiby.xu@gmail.com>.
	5	* Copyright (c) 2020 Red Hat, Inc.
	6	*
	7	* This work is licensed under the terms of the GNU GPL, version 2 or
	8	* later. See the COPYING file in the top-level directory.
	9	*/
	10	#include "qemu/osdep.h"
5feed38c	11	#include "qemu/error-report.h"
70eb2c07	12	#include "qemu/main-loop.h"
80a06cc5	13	#include "qemu/vhost-user-server.h"
7185c857	14	#include "block/aio-wait.h"
70eb2c07	15
7185c857 SH	16	/*
	17	* Theory of operation:
	18	*
	19	* VuServer is started and stopped by vhost_user_server_start() and
	20	* vhost_user_server_stop() from the main loop thread. Starting the server
	21	* opens a vhost-user UNIX domain socket and listens for incoming connections.
	22	* Only one connection is allowed at a time.
	23	*
	24	* The connection is handled by the vu_client_trip() coroutine in the
	25	* VuServer->ctx AioContext. The coroutine consists of a vu_dispatch() loop
	26	* where libvhost-user calls vu_message_read() to receive the next vhost-user
	27	* protocol messages over the UNIX domain socket.
	28	*
	29	* When virtqueues are set up libvhost-user calls set_watch() to monitor kick
	30	* fds. These fds are also handled in the VuServer->ctx AioContext.
	31	*
	32	* Both vu_client_trip() and kick fd monitoring can be stopped by shutting down
	33	* the socket connection. Shutting down the socket connection causes
	34	* vu_message_read() to fail since no more data can be received from the socket.
	35	* After vu_dispatch() fails, vu_client_trip() calls vu_deinit() to stop
	36	* libvhost-user before terminating the coroutine. vu_deinit() calls
	37	* remove_watch() to stop monitoring kick fds and this stops virtqueue
	38	* processing.
	39	*
	40	* When vu_client_trip() has finished cleaning up it schedules a BH in the main
	41	* loop thread to accept the next client connection.
	42	*
	43	* When libvhost-user detects an error it calls panic_cb() and sets the
	44	* dev->broken flag. Both vu_client_trip() and kick fd processing stop when
	45	* the dev->broken flag is set.
	46	*
	47	* It is possible to switch AioContexts using
	48	* vhost_user_server_detach_aio_context() and
	49	* vhost_user_server_attach_aio_context(). They stop monitoring fds in the old
	50	* AioContext and resume monitoring in the new AioContext. The vu_client_trip()
	51	* coroutine remains in a yielded state during the switch. This is made
	52	* possible by QIOChannel's support for spurious coroutine re-entry in
	53	* qio_channel_yield(). The coroutine will restart I/O when re-entered from the
	54	* new AioContext.
	55	*/
	56
70eb2c07 CX	57	static void vmsg_close_fds(VhostUserMsg *vmsg)
	58	{
	59	int i;
	60	for (i = 0; i < vmsg->fd_num; i++) {
	61	close(vmsg->fds[i]);
	62	}
	63	}
	64
	65	static void vmsg_unblock_fds(VhostUserMsg *vmsg)
	66	{
	67	int i;
	68	for (i = 0; i < vmsg->fd_num; i++) {
ff5927ba	69	qemu_socket_set_nonblock(vmsg->fds[i]);
70eb2c07 CX	70	}
	71	}
	72
70eb2c07 CX	73	static void panic_cb(VuDev vu_dev, const char buf)
70eb2c07 CX	74	{
7185c857	75	error_report("vu_panic: %s", buf);
70eb2c07 CX	76	}
70eb2c07 CX	77
75d33e85	78	void vhost_user_server_inc_in_flight(VuServer *server)
520d8b40 KW	79	{
520d8b40 KW	80	assert(!server->wait_idle);
8f5e9a8e	81	qatomic_inc(&server->in_flight);
520d8b40 KW	82	}
520d8b40 KW	83
75d33e85	84	void vhost_user_server_dec_in_flight(VuServer *server)
520d8b40	85	{
8f5e9a8e SH	86	if (qatomic_fetch_dec(&server->in_flight) == 1) {
	87	if (server->wait_idle) {
	88	aio_co_wake(server->co_trip);
	89	}
520d8b40 KW	90	}
	91	}
	92
8f5e9a8e SH	93	bool vhost_user_server_has_in_flight(VuServer *server)
	94	{
	95	return qatomic_load_acquire(&server->in_flight) > 0;
	96	}
	97
70eb2c07 CX	98	static bool coroutine_fn
	99	vu_message_read(VuDev vu_dev, int conn_fd, VhostUserMsg vmsg)
	100	{
	101	struct iovec iov = {
	102	.iov_base = (char *)vmsg,
	103	.iov_len = VHOST_USER_HDR_SIZE,
	104	};
	105	int rc, read_bytes = 0;
	106	Error *local_err = NULL;
70eb2c07	107	const size_t max_fds = G_N_ELEMENTS(vmsg->fds);
70eb2c07 CX	108	VuServer *server = container_of(vu_dev, VuServer, vu_dev);
	109	QIOChannel *ioc = server->ioc;
	110
8c7f7cbc	111	vmsg->fd_num = 0;
70eb2c07 CX	112	if (!ioc) {
	113	error_report_err(local_err);
	114	goto fail;
	115	}
	116
	117	assert(qemu_in_coroutine());
	118	do {
8c7f7cbc SH	119	size_t nfds = 0;
	120	int *fds = NULL;
	121
70eb2c07 CX	122	/*
	123	* qio_channel_readv_full may have short reads, keeping calling it
	124	* until getting VHOST_USER_HDR_SIZE or 0 bytes in total
	125	*/
84615a19	126	rc = qio_channel_readv_full(ioc, &iov, 1, &fds, &nfds, 0, &local_err);
70eb2c07 CX	127	if (rc < 0) {
70eb2c07 CX	128	if (rc == QIO_CHANNEL_ERR_BLOCK) {
8c7f7cbc	129	assert(local_err == NULL);
06e0f098 SH	130	if (server->ctx) {
	131	server->in_qio_channel_yield = true;
	132	qio_channel_yield(ioc, G_IO_IN);
	133	server->in_qio_channel_yield = false;
	134	} else {
	135	/* Wait until attached to an AioContext again */
	136	qemu_coroutine_yield();
	137	}
70eb2c07 CX	138	continue;
	139	} else {
	140	error_report_err(local_err);
8c7f7cbc	141	goto fail;
70eb2c07 CX	142	}
70eb2c07 CX	143	}
8c7f7cbc SH	144
	145	if (nfds > 0) {
	146	if (vmsg->fd_num + nfds > max_fds) {
70eb2c07 CX	147	error_report("A maximum of %zu fds are allowed, "
70eb2c07 CX	148	"however got %zu fds now",
8c7f7cbc SH	149	max_fds, vmsg->fd_num + nfds);
8c7f7cbc SH	150	g_free(fds);
70eb2c07 CX	151	goto fail;
70eb2c07 CX	152	}
8c7f7cbc SH	153	memcpy(vmsg->fds + vmsg->fd_num, fds, nfds * sizeof(vmsg->fds[0]));
	154	vmsg->fd_num += nfds;
	155	g_free(fds);
70eb2c07	156	}
8c7f7cbc SH	157
	158	if (rc == 0) { /* socket closed */
	159	goto fail;
70eb2c07	160	}
70eb2c07	161
8c7f7cbc SH	162	iov.iov_base += rc;
	163	iov.iov_len -= rc;
	164	read_bytes += rc;
	165	} while (read_bytes != VHOST_USER_HDR_SIZE);
	166
70eb2c07 CX	167	/* qio_channel_readv_full will make socket fds blocking, unblock them */
	168	vmsg_unblock_fds(vmsg);
	169	if (vmsg->size > sizeof(vmsg->payload)) {
	170	error_report("Error: too big message request: %d, "
	171	"size: vmsg->size: %u, "
	172	"while sizeof(vmsg->payload) = %zu",
	173	vmsg->request, vmsg->size, sizeof(vmsg->payload));
	174	goto fail;
	175	}
	176
	177	struct iovec iov_payload = {
	178	.iov_base = (char *)&vmsg->payload,
	179	.iov_len = vmsg->size,
	180	};
	181	if (vmsg->size) {
	182	rc = qio_channel_readv_all_eof(ioc, &iov_payload, 1, &local_err);
edaf6205 SH	183	if (rc != 1) {
	184	if (local_err) {
	185	error_report_err(local_err);
	186	}
70eb2c07 CX	187	goto fail;
	188	}
	189	}
	190
	191	return true;
	192
	193	fail:
	194	vmsg_close_fds(vmsg);
	195
	196	return false;
	197	}
	198
70eb2c07 CX	199	static coroutine_fn void vu_client_trip(void *opaque)
	200	{
	201	VuServer *server = opaque;
7185c857	202	VuDev *vu_dev = &server->vu_dev;
70eb2c07	203
7185c857 SH	204	while (!vu_dev->broken && vu_dispatch(vu_dev)) {
7185c857 SH	205	/* Keep running */
70eb2c07 CX	206	}
70eb2c07 CX	207
8f5e9a8e	208	if (vhost_user_server_has_in_flight(server)) {
520d8b40 KW	209	/* Wait for requests to complete before we can unmap the memory */
	210	server->wait_idle = true;
	211	qemu_coroutine_yield();
	212	server->wait_idle = false;
	213	}
8f5e9a8e	214	assert(!vhost_user_server_has_in_flight(server));
520d8b40	215
7185c857	216	vu_deinit(vu_dev);
70eb2c07	217
7185c857 SH	218	/* vu_deinit() should have called remove_watch() */
	219	assert(QTAILQ_EMPTY(&server->vu_fd_watches));
	220
	221	object_unref(OBJECT(server->sioc));
	222	server->sioc = NULL;
	223
	224	object_unref(OBJECT(server->ioc));
	225	server->ioc = NULL;
	226
	227	server->co_trip = NULL;
	228	if (server->restart_listener_bh) {
	229	qemu_bh_schedule(server->restart_listener_bh);
	230	}
	231	aio_wait_kick();
70eb2c07 CX	232	}
	233
	234	/*
	235	* a wrapper for vu_kick_cb
	236	*
	237	* since aio_dispatch can only pass one user data pointer to the
	238	* callback function, pack VuDev and pvt into a struct. Then unpack it
	239	* and pass them to vu_kick_cb
	240	*/
	241	static void kick_handler(void *opaque)
	242	{
	243	VuFdWatch *vu_fd_watch = opaque;
7185c857	244	VuDev *vu_dev = vu_fd_watch->vu_dev;
70eb2c07	245
7185c857 SH	246	vu_fd_watch->cb(vu_dev, 0, vu_fd_watch->pvt);
	247
	248	/* Stop vu_client_trip() if an error occurred in vu_fd_watch->cb() */
	249	if (vu_dev->broken) {
	250	VuServer *server = container_of(vu_dev, VuServer, vu_dev);
	251
	252	qio_channel_shutdown(server->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
	253	}
	254	}
70eb2c07 CX	255
	256	static VuFdWatch find_vu_fd_watch(VuServer server, int fd)
	257	{
	258
	259	VuFdWatch vu_fd_watch, next;
	260	QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) {
	261	if (vu_fd_watch->fd == fd) {
	262	return vu_fd_watch;
	263	}
	264	}
	265	return NULL;
	266	}
	267
	268	static void
	269	set_watch(VuDev *vu_dev, int fd, int vu_evt,
	270	vu_watch_cb cb, void *pvt)
	271	{
	272
	273	VuServer *server = container_of(vu_dev, VuServer, vu_dev);
	274	g_assert(vu_dev);
	275	g_assert(fd >= 0);
	276	g_assert(cb);
	277
	278	VuFdWatch *vu_fd_watch = find_vu_fd_watch(server, fd);
	279
	280	if (!vu_fd_watch) {
	281	VuFdWatch *vu_fd_watch = g_new0(VuFdWatch, 1);
	282
	283	QTAILQ_INSERT_TAIL(&server->vu_fd_watches, vu_fd_watch, next);
	284
	285	vu_fd_watch->fd = fd;
	286	vu_fd_watch->cb = cb;
ff5927ba	287	qemu_socket_set_nonblock(fd);
06e0f098	288	aio_set_fd_handler(server->ctx, fd, kick_handler,
826cc324	289	NULL, NULL, NULL, vu_fd_watch);
70eb2c07 CX	290	vu_fd_watch->vu_dev = vu_dev;
	291	vu_fd_watch->pvt = pvt;
	292	}
	293	}
	294
	295
	296	static void remove_watch(VuDev *vu_dev, int fd)
	297	{
	298	VuServer *server;
	299	g_assert(vu_dev);
	300	g_assert(fd >= 0);
	301
	302	server = container_of(vu_dev, VuServer, vu_dev);
	303
	304	VuFdWatch *vu_fd_watch = find_vu_fd_watch(server, fd);
	305
	306	if (!vu_fd_watch) {
	307	return;
	308	}
06e0f098	309	aio_set_fd_handler(server->ctx, fd, NULL, NULL, NULL, NULL, NULL);
70eb2c07 CX	310
	311	QTAILQ_REMOVE(&server->vu_fd_watches, vu_fd_watch, next);
	312	g_free(vu_fd_watch);
	313	}
	314
	315
	316	static void vu_accept(QIONetListener listener, QIOChannelSocket sioc,
	317	gpointer opaque)
	318	{
	319	VuServer *server = opaque;
	320
	321	if (server->sioc) {
	322	warn_report("Only one vhost-user client is allowed to "
	323	"connect the server one time");
	324	return;
	325	}
	326
	327	if (!vu_init(&server->vu_dev, server->max_queues, sioc->fd, panic_cb,
	328	vu_message_read, set_watch, remove_watch, server->vu_iface)) {
	329	error_report("Failed to initialize libvhost-user");
	330	return;
	331	}
	332
	333	/*
	334	* Unset the callback function for network listener to make another
	335	* vhost-user client keeping waiting until this client disconnects
	336	*/
	337	qio_net_listener_set_client_func(server->listener,
	338	NULL,
	339	NULL,
	340	NULL);
	341	server->sioc = sioc;
	342	/*
	343	* Increase the object reference, so sioc will not freed by
	344	* qio_net_listener_channel_func which will call object_unref(OBJECT(sioc))
	345	*/
	346	object_ref(OBJECT(server->sioc));
	347	qio_channel_set_name(QIO_CHANNEL(sioc), "vhost-user client");
	348	server->ioc = QIO_CHANNEL(sioc);
	349	object_ref(OBJECT(server->ioc));
7185c857 SH	350
7185c857 SH	351	/* TODO vu_message_write() spins if non-blocking! */
46a096c8	352	qio_channel_set_blocking(server->ioc, false, NULL);
70eb2c07	353
06e0f098 SH	354	qio_channel_set_follow_coroutine_ctx(server->ioc, true);
06e0f098 SH	355
7185c857 SH	356	server->co_trip = qemu_coroutine_create(vu_client_trip, server);
	357
	358	aio_context_acquire(server->ctx);
	359	vhost_user_server_attach_aio_context(server, server->ctx);
	360	aio_context_release(server->ctx);
	361	}
70eb2c07	362
2957dc40	363	/* server->ctx acquired by caller */
70eb2c07 CX	364	void vhost_user_server_stop(VuServer *server)
70eb2c07 CX	365	{
7185c857 SH	366	qemu_bh_delete(server->restart_listener_bh);
	367	server->restart_listener_bh = NULL;
	368
70eb2c07	369	if (server->sioc) {
7185c857 SH	370	VuFdWatch *vu_fd_watch;
	371
	372	QTAILQ_FOREACH(vu_fd_watch, &server->vu_fd_watches, next) {
60f782b6	373	aio_set_fd_handler(server->ctx, vu_fd_watch->fd,
826cc324	374	NULL, NULL, NULL, NULL, vu_fd_watch);
7185c857 SH	375	}
	376
	377	qio_channel_shutdown(server->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
	378
	379	AIO_WAIT_WHILE(server->ctx, server->co_trip);
70eb2c07 CX	380	}
	381
	382	if (server->listener) {
	383	qio_net_listener_disconnect(server->listener);
	384	object_unref(OBJECT(server->listener));
	385	}
7185c857 SH	386	}
	387
	388	/*
	389	* Allow the next client to connect to the server. Called from a BH in the main
	390	* loop.
	391	*/
	392	static void restart_listener_bh(void *opaque)
	393	{
	394	VuServer *server = opaque;
70eb2c07	395
7185c857 SH	396	qio_net_listener_set_client_func(server->listener, vu_accept, server,
7185c857 SH	397	NULL);
70eb2c07 CX	398	}
70eb2c07 CX	399
7185c857 SH	400	/* Called with ctx acquired */
7185c857 SH	401	void vhost_user_server_attach_aio_context(VuServer server, AioContext ctx)
70eb2c07	402	{
7185c857	403	VuFdWatch *vu_fd_watch;
70eb2c07	404
7185c857	405	server->ctx = ctx;
70eb2c07 CX	406
70eb2c07 CX	407	if (!server->sioc) {
70eb2c07 CX	408	return;
	409	}
	410
7185c857	411	QTAILQ_FOREACH(vu_fd_watch, &server->vu_fd_watches, next) {
60f782b6	412	aio_set_fd_handler(ctx, vu_fd_watch->fd, kick_handler, NULL,
826cc324	413	NULL, NULL, vu_fd_watch);
70eb2c07 CX	414	}
70eb2c07 CX	415
06e0f098	416	assert(!server->in_qio_channel_yield);
7185c857 SH	417	aio_co_schedule(ctx, server->co_trip);
	418	}
	419
	420	/* Called with server->ctx acquired */
	421	void vhost_user_server_detach_aio_context(VuServer *server)
	422	{
	423	if (server->sioc) {
	424	VuFdWatch *vu_fd_watch;
	425
	426	QTAILQ_FOREACH(vu_fd_watch, &server->vu_fd_watches, next) {
60f782b6	427	aio_set_fd_handler(server->ctx, vu_fd_watch->fd,
826cc324	428	NULL, NULL, NULL, NULL, vu_fd_watch);
70eb2c07 CX	429	}
70eb2c07 CX	430	}
70eb2c07	431
7185c857	432	server->ctx = NULL;
06e0f098 SH	433
	434	if (server->ioc) {
	435	if (server->in_qio_channel_yield) {
	436	/* Stop receiving the next vhost-user message */
	437	qio_channel_wake_read(server->ioc);
	438	}
	439	}
7185c857	440	}
70eb2c07 CX	441
	442	bool vhost_user_server_start(VuServer *server,
	443	SocketAddress *socket_addr,
	444	AioContext *ctx,
	445	uint16_t max_queues,
70eb2c07 CX	446	const VuDevIface *vu_iface,
	447	Error **errp)
	448	{
7185c857	449	QEMUBH *bh;
90fc91d5 SH	450	QIONetListener *listener;
	451
	452	if (socket_addr->type != SOCKET_ADDRESS_TYPE_UNIX &&
	453	socket_addr->type != SOCKET_ADDRESS_TYPE_FD) {
	454	error_setg(errp, "Only socket address types 'unix' and 'fd' are supported");
	455	return false;
	456	}
	457
	458	listener = qio_net_listener_new();
70eb2c07 CX	459	if (qio_net_listener_open_sync(listener, socket_addr, 1,
	460	errp) < 0) {
	461	object_unref(OBJECT(listener));
	462	return false;
	463	}
	464
7185c857 SH	465	bh = qemu_bh_new(restart_listener_bh, server);
7185c857 SH	466
1d787456	467	/* zero out unspecified fields */
70eb2c07 CX	468	*server = (VuServer) {
70eb2c07 CX	469	.listener = listener,
7185c857	470	.restart_listener_bh = bh,
70eb2c07 CX	471	.vu_iface = vu_iface,
	472	.max_queues = max_queues,
	473	.ctx = ctx,
70eb2c07 CX	474	};
	475
	476	qio_net_listener_set_name(server->listener, "vhost-user-backend-listener");
	477
	478	qio_net_listener_set_client_func(server->listener,
	479	vu_accept,
	480	server,
	481	NULL);
	482
	483	QTAILQ_INIT(&server->vu_fd_watches);
	484	return true;
	485	}