From 70eb2c079cdfa835c70aec8887710b18092516a0 Mon Sep 17 00:00:00 2001 From: Coiby Xu Date: Fri, 18 Sep 2020 16:09:08 +0800 Subject: util/vhost-user-server: generic vhost user server MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sharing QEMU devices via vhost-user protocol. Only one vhost-user client can connect to the server one time. Suggested-by: Kevin Wolf Signed-off-by: Stefan Hajnoczi Signed-off-by: Coiby Xu Reviewed-by: Stefan Hajnoczi Reviewed-by: Marc-André Lureau Message-id: 20200918080912.321299-4-coiby.xu@gmail.com [Fixed size_t %lu -> %zu format string compiler error. --Stefan] Signed-off-by: Stefan Hajnoczi --- util/meson.build | 1 + util/vhost-user-server.c | 428 +++++++++++++++++++++++++++++++++++++++++++++++ util/vhost-user-server.h | 65 +++++++ 3 files changed, 494 insertions(+) create mode 100644 util/vhost-user-server.c create mode 100644 util/vhost-user-server.h (limited to 'util') diff --git a/util/meson.build b/util/meson.build index e6b207a..3921981 100644 --- a/util/meson.build +++ b/util/meson.build @@ -66,6 +66,7 @@ if have_block util_ss.add(files('main-loop.c')) util_ss.add(files('nvdimm-utils.c')) util_ss.add(files('qemu-coroutine.c', 'qemu-coroutine-lock.c', 'qemu-coroutine-io.c')) + util_ss.add(when: 'CONFIG_LINUX', if_true: files('vhost-user-server.c')) util_ss.add(files('qemu-coroutine-sleep.c')) util_ss.add(files('qemu-co-shared-resource.c')) util_ss.add(files('thread-pool.c', 'qemu-timer.c')) diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c new file mode 100644 index 0000000..b189944 --- /dev/null +++ b/util/vhost-user-server.c @@ -0,0 +1,428 @@ +/* + * Sharing QEMU devices via vhost-user protocol + * + * Copyright (c) Coiby Xu . + * 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/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 vu_accept(QIONetListener *listener, QIOChannelSocket *sioc, + gpointer opaque); + +static void close_client(VuServer *server) +{ + /* + * Before closing the client + * + * 1. Let vu_client_trip stop processing new vhost-user msg + * + * 2. remove kick_handler + * + * 3. wait for the kick handler to be finished + * + * 4. wait for the current vhost-user msg to be finished processing + */ + + QIOChannelSocket *sioc = server->sioc; + /* When this is set vu_client_trip will stop new processing vhost-user message */ + server->sioc = NULL; + + VuFdWatch *vu_fd_watch, *next; + QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) { + aio_set_fd_handler(server->ioc->ctx, vu_fd_watch->fd, true, NULL, + NULL, NULL, NULL); + } + + while (!QTAILQ_EMPTY(&server->vu_fd_watches)) { + QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) { + if (!vu_fd_watch->processing) { + QTAILQ_REMOVE(&server->vu_fd_watches, vu_fd_watch, next); + g_free(vu_fd_watch); + } + } + } + + while (server->processing_msg) { + if (server->ioc->read_coroutine) { + server->ioc->read_coroutine = NULL; + qio_channel_set_aio_fd_handler(server->ioc, server->ioc->ctx, NULL, + NULL, server->ioc); + server->processing_msg = false; + } + } + + vu_deinit(&server->vu_dev); + object_unref(OBJECT(sioc)); + object_unref(OBJECT(server->ioc)); +} + +static void panic_cb(VuDev *vu_dev, const char *buf) +{ + VuServer *server = container_of(vu_dev, VuServer, vu_dev); + + /* avoid while loop in close_client */ + server->processing_msg = false; + + if (buf) { + error_report("vu_panic: %s", buf); + } + + if (server->sioc) { + close_client(server); + } + + if (server->device_panic_notifier) { + server->device_panic_notifier(server); + } + + /* + * Set the callback function for network listener so another + * vhost-user client can connect to this server + */ + qio_net_listener_set_client_func(server->listener, + vu_accept, + server, + NULL); +} + +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; + /* + * 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; + const size_t max_fds = G_N_ELEMENTS(vmsg->fds); + int *fds_t = NULL; + VuServer *server = container_of(vu_dev, VuServer, vu_dev); + QIOChannel *ioc = server->ioc; + + if (!ioc) { + error_report_err(local_err); + goto fail; + } + + 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; + if (nfds_t > 0) { + if (nfds + nfds_t > max_fds) { + error_report("A maximum of %zu fds are allowed, " + "however got %zu fds now", + max_fds, nfds + nfds_t); + goto fail; + } + memcpy(vmsg->fds + nfds, fds_t, + nfds_t *sizeof(vmsg->fds[0])); + nfds += nfds_t; + g_free(fds_t); + } + if (read_bytes == VHOST_USER_HDR_SIZE || rc == 0) { + break; + } + iov.iov_base = (char *)vmsg + read_bytes; + iov.iov_len = VHOST_USER_HDR_SIZE - read_bytes; + } while (true); + + vmsg->fd_num = nfds; + /* 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(VuServer *server); +static coroutine_fn void vu_client_trip(void *opaque) +{ + VuServer *server = opaque; + + while (!server->aio_context_changed && server->sioc) { + server->processing_msg = true; + vu_dispatch(&server->vu_dev); + server->processing_msg = false; + } + + if (server->aio_context_changed && server->sioc) { + server->aio_context_changed = false; + vu_client_start(server); + } +} + +static void vu_client_start(VuServer *server) +{ + server->co_trip = qemu_coroutine_create(vu_client_trip, server); + aio_co_enter(server->ctx, server->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) +{ + VuFdWatch *vu_fd_watch = opaque; + vu_fd_watch->processing = true; + vu_fd_watch->cb(vu_fd_watch->vu_dev, 0, vu_fd_watch->pvt); + vu_fd_watch->processing = false; +} + + +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_set_nonblock(fd); + aio_set_fd_handler(server->ioc->ctx, fd, true, kick_handler, + 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->ioc->ctx, fd, true, 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)); + qio_channel_attach_aio_context(server->ioc, server->ctx); + qio_channel_set_blocking(QIO_CHANNEL(server->sioc), false, NULL); + vu_client_start(server); +} + + +void vhost_user_server_stop(VuServer *server) +{ + if (server->sioc) { + close_client(server); + } + + if (server->listener) { + qio_net_listener_disconnect(server->listener); + object_unref(OBJECT(server->listener)); + } + +} + +void vhost_user_server_set_aio_context(VuServer *server, AioContext *ctx) +{ + VuFdWatch *vu_fd_watch, *next; + void *opaque = NULL; + IOHandler *io_read = NULL; + bool attach; + + server->ctx = ctx ? ctx : qemu_get_aio_context(); + + if (!server->sioc) { + /* not yet serving any client*/ + return; + } + + if (ctx) { + qio_channel_attach_aio_context(server->ioc, ctx); + server->aio_context_changed = true; + io_read = kick_handler; + attach = true; + } else { + qio_channel_detach_aio_context(server->ioc); + /* server->ioc->ctx keeps the old AioConext */ + ctx = server->ioc->ctx; + attach = false; + } + + QTAILQ_FOREACH_SAFE(vu_fd_watch, &server->vu_fd_watches, next, next) { + if (vu_fd_watch->cb) { + opaque = attach ? vu_fd_watch : NULL; + aio_set_fd_handler(ctx, vu_fd_watch->fd, true, + io_read, NULL, NULL, + opaque); + } + } +} + + +bool vhost_user_server_start(VuServer *server, + SocketAddress *socket_addr, + AioContext *ctx, + uint16_t max_queues, + DevicePanicNotifierFn *device_panic_notifier, + const VuDevIface *vu_iface, + Error **errp) +{ + QIONetListener *listener = qio_net_listener_new(); + if (qio_net_listener_open_sync(listener, socket_addr, 1, + errp) < 0) { + object_unref(OBJECT(listener)); + return false; + } + + /* zero out unspecified fileds */ + *server = (VuServer) { + .listener = listener, + .vu_iface = vu_iface, + .max_queues = max_queues, + .ctx = ctx, + .device_panic_notifier = device_panic_notifier, + }; + + 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; +} diff --git a/util/vhost-user-server.h b/util/vhost-user-server.h new file mode 100644 index 0000000..5232f96 --- /dev/null +++ b/util/vhost-user-server.h @@ -0,0 +1,65 @@ +/* + * Sharing QEMU devices via vhost-user protocol + * + * Copyright (c) Coiby Xu . + * 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. + */ + +#ifndef VHOST_USER_SERVER_H +#define VHOST_USER_SERVER_H + +#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 VuFdWatch { + VuDev *vu_dev; + int fd; /*kick fd*/ + void *pvt; + vu_watch_cb cb; + bool processing; + QTAILQ_ENTRY(VuFdWatch) next; +} VuFdWatch; + +typedef struct VuServer VuServer; +typedef void DevicePanicNotifierFn(VuServer *server); + +struct VuServer { + QIONetListener *listener; + AioContext *ctx; + DevicePanicNotifierFn *device_panic_notifier; + int max_queues; + const VuDevIface *vu_iface; + VuDev vu_dev; + QIOChannel *ioc; /* The I/O channel with the client */ + QIOChannelSocket *sioc; /* The underlying data channel with the client */ + /* IOChannel for fd provided via VHOST_USER_SET_SLAVE_REQ_FD */ + QIOChannel *ioc_slave; + QIOChannelSocket *sioc_slave; + Coroutine *co_trip; /* coroutine for processing VhostUserMsg */ + QTAILQ_HEAD(, VuFdWatch) vu_fd_watches; + /* restart coroutine co_trip if AIOContext is changed */ + bool aio_context_changed; + bool processing_msg; +}; + +bool vhost_user_server_start(VuServer *server, + SocketAddress *unix_socket, + AioContext *ctx, + uint16_t max_queues, + DevicePanicNotifierFn *device_panic_notifier, + const VuDevIface *vu_iface, + Error **errp); + +void vhost_user_server_stop(VuServer *server); + +void vhost_user_server_set_aio_context(VuServer *server, AioContext *ctx); + +#endif /* VHOST_USER_SERVER_H */ -- cgit v1.1