Sharing QEMU devices via vhost-user protocol Signed-off-by: Coiby Xu <coiby...@gmail.com> --- util/Makefile.objs | 3 + util/vhost-user-server.c | 360 +++++++++++++++++++++++++++++++++++++++ util/vhost-user-server.h | 57 ++++++ 3 files changed, 420 insertions(+) create mode 100644 util/vhost-user-server.c create mode 100644 util/vhost-user-server.h
diff --git a/util/Makefile.objs b/util/Makefile.objs index 6b38b67cf1..d207b5f981 100644 --- a/util/Makefile.objs +++ b/util/Makefile.objs @@ -37,6 +37,9 @@ util-obj-y += readline.o util-obj-y += rcu.o util-obj-$(CONFIG_MEMBARRIER) += sys_membarrier.o util-obj-y += qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o +ifdef CONFIG_LINUX +util-obj-y += vhost-user-server.o +endif util-obj-y += qemu-coroutine-sleep.o util-obj-y += qemu-co-shared-resource.o util-obj-y += coroutine-$(CONFIG_COROUTINE_BACKEND).o diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c new file mode 100644 index 0000000000..7da96bc815 --- /dev/null +++ b/util/vhost-user-server.c @@ -0,0 +1,360 @@ +/* + * Sharing QEMU devices via vhost-user protocol + * + * Author: Coiby Xu <coiby...@gmail.com> + * + * 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 <sys/eventfd.h> +#include "qemu/main-loop.h" +#include "vhost-user-server.h" + +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_set_nonblock(vmsg->fds[i]); + } +} + + +static void close_client(VuClientInfo *client) +{ + vu_deinit(&client->vu_dev); + client->sioc = NULL; + object_unref(OBJECT(client->ioc)); + client->closed = true; + +} + +static void panic_cb(VuDev *vu_dev, const char *buf) +{ + VuClientInfo *client = container_of(vu_dev, VuClientInfo, vu_dev); + VuServer *server = client->server; + + if (buf) { + error_report("vu_panic: %s", buf); + } + + if (!client->closed) { + close_client(client); + QTAILQ_REMOVE(&server->clients, client, next); + } + + if (server->device_panic_notifier) { + server->device_panic_notifier(client); + } +} + + + +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; + /* + * Store fds/nfds returned from qio_channel_readv_full into + * temporary variables. + * + * VhostUserMsg is a packed structure, gcc will complain about passing + * pointer to a packed structure member if we pass &VhostUserMsg.fd_num + * and &VhostUserMsg.fds directly when calling qio_channel_readv_full, + * thus two temporary variables nfds and fds are used here. + */ + size_t nfds = 0, nfds_t = 0; + int *fds = NULL, *fds_t = NULL; + VuClientInfo *client = container_of(vu_dev, VuClientInfo, vu_dev); + QIOChannel *ioc = client->ioc; + + Error *local_err = NULL; + assert(qemu_in_coroutine()); + do { + /* + * 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_t, &nfds_t, &local_err); + if (rc < 0) { + if (rc == QIO_CHANNEL_ERR_BLOCK) { + qio_channel_yield(ioc, G_IO_IN); + continue; + } else { + error_report_err(local_err); + return false; + } + } + read_bytes += rc; + fds = g_renew(int, fds_t, nfds + nfds_t); + memcpy(fds + nfds, fds_t, nfds_t); + nfds += nfds_t; + if (read_bytes == VHOST_USER_HDR_SIZE || rc == 0) { + break; + } + } while (true); + assert(nfds <= VHOST_MEMORY_MAX_NREGIONS); + vmsg->fd_num = nfds; + memcpy(vmsg->fds, fds, nfds * sizeof(int)); + g_free(fds); + /* 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) { + error_report_err(local_err); + goto fail; + } + } + + return true; + +fail: + vmsg_close_fds(vmsg); + + return false; +} + + +static void vu_client_start(VuClientInfo *client); +static coroutine_fn void vu_client_trip(void *opaque) +{ + VuClientInfo *client = opaque; + + while (!client->aio_context_changed && !client->closed) { + vu_dispatch(&client->vu_dev); + } + + if (client->aio_context_changed) { + client->aio_context_changed = false; + vu_client_start(client); + } +} + +static void vu_client_start(VuClientInfo *client) +{ + client->co_trip = qemu_coroutine_create(vu_client_trip, client); + aio_co_enter(client->ioc->ctx, client->co_trip); +} + +/* + * 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) +{ + KickInfo *kick_info = opaque; + kick_info->cb(kick_info->vu_dev, 0, (void *) kick_info->index); +} + + +static void +set_watch(VuDev *vu_dev, int fd, int vu_evt, + vu_watch_cb cb, void *pvt) +{ + + VuClientInfo *client; + client = container_of(vu_dev, VuClientInfo, vu_dev); + g_assert(vu_dev); + g_assert(fd >= 0); + long index = (intptr_t) pvt; + g_assert(cb); + KickInfo *kick_info = &client->kick_info[index]; + if (!kick_info->cb) { + kick_info->fd = fd; + kick_info->cb = cb; + qemu_set_nonblock(fd); + aio_set_fd_handler(client->ioc->ctx, fd, false, kick_handler, + NULL, NULL, kick_info); + kick_info->vu_dev = vu_dev; + } +} + + +static void remove_watch(VuDev *vu_dev, int fd) +{ + VuClientInfo *client; + int i; + int index = -1; + g_assert(vu_dev); + g_assert(fd >= 0); + + client = container_of(vu_dev, VuClientInfo, vu_dev); + for (i = 0; i < vu_dev->max_queues; i++) { + if (client->kick_info[i].fd == fd) { + index = i; + break; + } + } + + if (index == -1) { + return; + } + client->kick_info[i].cb = NULL; + aio_set_fd_handler(client->ioc->ctx, fd, false, NULL, NULL, NULL, NULL); +} + + +static void vu_accept(QIONetListener *listener, QIOChannelSocket *sioc, + gpointer opaque) +{ + VuClientInfo *client; + VuServer *server = opaque; + client = g_new0(VuClientInfo, 1); + if (!vu_init(&client->vu_dev, server->max_queues, sioc->fd, panic_cb, + vu_message_read, set_watch, remove_watch, server->vu_iface)) { + error_report("Failed to initialized libvhost-user"); + g_free(client); + return; + } + + client->server = server; + client->sioc = sioc; + client->kick_info = g_new0(KickInfo, server->max_queues); + /* + * increase the object reference, so cioc will not freed by + * qio_net_listener_channel_func which will call object_unref(OBJECT(sioc)) + */ + object_ref(OBJECT(client->sioc)); + qio_channel_set_name(QIO_CHANNEL(sioc), "vhost-user client"); + client->ioc = QIO_CHANNEL(sioc); + object_ref(OBJECT(client->ioc)); + object_ref(OBJECT(sioc)); + qio_channel_attach_aio_context(client->ioc, server->ctx); + qio_channel_set_blocking(QIO_CHANNEL(client->sioc), false, NULL); + client->closed = false; + QTAILQ_INSERT_TAIL(&server->clients, client, next); + vu_client_start(client); +} + + +void vhost_user_server_stop(VuServer *server) +{ + if (!server) { + return; + } + + VuClientInfo *client, *next; + QTAILQ_FOREACH_SAFE(client, &server->clients, next, next) { + if (!client->closed) { + close_client(client); + QTAILQ_REMOVE(&server->clients, client, next); + } + } + + if (server->listener) { + qio_net_listener_disconnect(server->listener); + object_unref(OBJECT(server->listener)); + } +} + +static void detach_context(VuServer *server) +{ + VuClientInfo *client; + int i; + QTAILQ_FOREACH(client, &server->clients, next) { + qio_channel_detach_aio_context(client->ioc); + AioContext *ctx = client->ioc->ctx; + for (i = 0; i < client->vu_dev.max_queues; i++) { + if (client->kick_info[i].cb) { + aio_set_fd_handler(ctx, client->kick_info[i].fd, false, NULL, + NULL, NULL, NULL); + } + } + } +} + +static void attach_context(VuServer *server, AioContext *ctx) +{ + VuClientInfo *client; + int i; + QTAILQ_FOREACH(client, &server->clients, next) { + qio_channel_attach_aio_context(client->ioc, ctx); + client->aio_context_changed = true; + if (client->co_trip) { + aio_co_schedule(ctx, client->co_trip); + } + for (i = 0; i < client->vu_dev.max_queues; i++) { + if (client->kick_info[i].cb) { + aio_set_fd_handler(ctx, client->kick_info[i].fd, false, + kick_handler, NULL, NULL, + &client->kick_info[i]); + } + } + } +} + +void vhost_user_server_set_aio_context(AioContext *ctx, VuServer *server) +{ + AioContext *acquire_ctx = ctx ? ctx : server->ctx; + aio_context_acquire(acquire_ctx); + server->ctx = ctx ? ctx : qemu_get_aio_context(); + if (ctx) { + attach_context(server, ctx); + } else { + detach_context(server); + } + aio_context_release(acquire_ctx); +} + + +VuServer *vhost_user_server_start(uint16_t max_queues, + SocketAddress *socket_addr, + AioContext *ctx, + void *server_ptr, + void *device_panic_notifier, + const VuDevIface *vu_iface, + Error **errp) +{ + VuServer *server = g_new0(VuServer, 1); + server->ptr_in_device = server_ptr; + server->listener = qio_net_listener_new(); + if (qio_net_listener_open_sync(server->listener, socket_addr, 1, + errp) < 0) { + goto error; + } + + qio_net_listener_set_name(server->listener, "vhost-user-backend-listener"); + + server->vu_iface = vu_iface; + server->max_queues = max_queues; + server->ctx = ctx; + server->device_panic_notifier = device_panic_notifier; + qio_net_listener_set_client_func(server->listener, + vu_accept, + server, + NULL); + + QTAILQ_INIT(&server->clients); + return server; +error: + g_free(server); + return NULL; +} diff --git a/util/vhost-user-server.h b/util/vhost-user-server.h new file mode 100644 index 0000000000..1a6b5e4ea9 --- /dev/null +++ b/util/vhost-user-server.h @@ -0,0 +1,57 @@ +#include "contrib/libvhost-user/libvhost-user.h" +#include "io/channel-socket.h" +#include "io/channel-file.h" +#include "io/net-listener.h" +#include "qemu/error-report.h" +#include "qapi/error.h" +#include "standard-headers/linux/virtio_blk.h" + +typedef struct VuClientInfo VuClientInfo; + +typedef struct VuServer { + QIONetListener *listener; + AioContext *ctx; + QTAILQ_HEAD(, VuClientInfo) clients; + void (*device_panic_notifier)(struct VuClientInfo *client) ; + int max_queues; + const VuDevIface *vu_iface; + /* + * @ptr_in_device: VuServer pointer memory location in vhost-user device + * struct, so later container_of can be used to get device destruct + */ + void *ptr_in_device; + bool close; +} VuServer; + +typedef struct KickInfo { + VuDev *vu_dev; + int fd; /*kick fd*/ + long index; /*queue index*/ + vu_watch_cb cb; +} KickInfo; + +struct VuClientInfo { + VuDev vu_dev; + VuServer *server; + QIOChannel *ioc; /* The current I/O channel */ + QIOChannelSocket *sioc; /* The underlying data channel */ + Coroutine *co_trip; /* coroutine for processing VhostUserMsg */ + KickInfo *kick_info; /* an array with the length of the queue number */ + QTAILQ_ENTRY(VuClientInfo) next; + /* restart coroutine co_trip if AIOContext is changed */ + bool aio_context_changed; + bool closed; +}; + + +VuServer *vhost_user_server_start(uint16_t max_queues, + SocketAddress *unix_socket, + AioContext *ctx, + void *server_ptr, + void *device_panic_notifier, + const VuDevIface *vu_iface, + Error **errp); + +void vhost_user_server_stop(VuServer *server); + +void vhost_user_server_set_aio_context(AioContext *ctx, VuServer *server); -- 2.25.1