Sharing QEMU devices via vhost-user protocol.
Only one vhost-user client can connect to the server one time.
Signed-off-by: Coiby Xu <coiby...@gmail.com>
---
util/Makefile.objs | 1 +
util/vhost-user-server.c | 406 +++++++++++++++++++++++++++++++++++++++
util/vhost-user-server.h | 59 ++++++
3 files changed, 466 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 fe339c2636..f54a6c80ec 100644
--- a/util/Makefile.objs
+++ b/util/Makefile.objs
@@ -40,6 +40,7 @@ util-obj-y += readline.o
util-obj-y += rcu.o
util-obj-$(CONFIG_MEMBARRIER) += sys_membarrier.o
util-obj-y += qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o
+util-obj-$(CONFIG_LINUX) += vhost-user-server.o
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..8fafd97bdc
--- /dev/null
+++ b/util/vhost-user-server.c
@@ -0,0 +1,406 @@
+/*
+ * 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 vu_accept(QIONetListener *listener, QIOChannelSocket *sioc,
+ gpointer opaque);
+
+static void close_client(VuServer *server)
+{
+ vu_deinit(&server->vu_dev);
+ server->sioc = NULL;
+ object_unref(OBJECT(server->ioc));
+
+ server->sioc_slave = NULL;
+ object_unref(OBJECT(server->ioc_slave));
+ /*
+ * 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 void panic_cb(VuDev *vu_dev, const char *buf)
+{
+ VuServer *server = container_of(vu_dev, VuServer, vu_dev);
+
+ if (buf) {
+ error_report("vu_panic: %s", buf);
+ }
+
+ if (server->sioc) {
+ close_client(server);
+ }
+
+ if (server->device_panic_notifier) {
+ server->device_panic_notifier(server);
+ }
+}
+
+static QIOChannel *slave_io_channel(VuServer *server, int fd,
+ Error **local_err)
+{
+ if (server->sioc_slave) {
+ if (fd == server->sioc_slave->fd) {
+ return server->ioc_slave;
+ }
+ } else {
+ server->sioc_slave = qio_channel_socket_new_fd(fd, local_err);
+ if (!*local_err) {
+ server->ioc_slave = QIO_CHANNEL(server->sioc_slave);
+ return server->ioc_slave;
+ }
+ }
+
+ return 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;
+ int *fds = NULL, *fds_t = NULL;
+ VuServer *server = container_of(vu_dev, VuServer, vu_dev);
+ QIOChannel *ioc = NULL;
+
+ if (conn_fd == server->sioc->fd) {
+ ioc = server->ioc;
+ } else {
+ /* Slave communication will also use this function to read msg */
+ ioc = slave_io_channel(server, conn_fd, &local_err);
+ }
+
+ 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) {
+ fds = g_renew(int, fds, nfds + nfds_t);
+ memcpy(fds + nfds, fds_t, nfds_t *sizeof(int));
+ nfds += nfds_t;
+ if (nfds > VHOST_MEMORY_MAX_NREGIONS) {
+ error_report("A maximum of %d fds are allowed, "
+ "however got %lu fds now",
+ VHOST_MEMORY_MAX_NREGIONS, nfds);
+ goto fail;
+ }
+ 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;
+ if (nfds > 0) {
+ 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(VuServer *server);
+static coroutine_fn void vu_client_trip(void *opaque)
+{
+ VuServer *server = opaque;
+
+ while (!server->aio_context_changed && server->sioc) {
+ vu_dispatch(&server->vu_dev);
+ }
+
+ 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)
+{
+ 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)
+{
+
+ VuServer *server = container_of(vu_dev, VuServer, vu_dev);
+ g_assert(vu_dev);
+ g_assert(fd >= 0);
+ long index = (intptr_t) pvt;
+ g_assert(cb);
+ KickInfo *kick_info = &server->kick_info[index];
+ if (!kick_info->cb) {
+ kick_info->fd = fd;
+ kick_info->cb = cb;
+ qemu_set_nonblock(fd);
+ aio_set_fd_handler(server->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)
+{
+ VuServer *server;
+ int i;
+ int index = -1;
+ g_assert(vu_dev);
+ g_assert(fd >= 0);
+
+ server = container_of(vu_dev, VuServer, vu_dev);
+ for (i = 0; i < vu_dev->max_queues; i++) {
+ if (server->kick_info[i].fd == fd) {
+ index = i;
+ break;
+ }
+ }
+
+ if (index == -1) {
+ return;
+ }
+ server->kick_info[i].cb = NULL;
+ aio_set_fd_handler(server->ioc->ctx, fd, false, NULL, NULL, NULL, NULL);
+}
+
+
+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 initialized 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;
+ server->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(server->sioc));
+ qio_channel_set_name(QIO_CHANNEL(sioc), "vhost-user client");
+ server->ioc = QIO_CHANNEL(sioc);
+ object_ref(OBJECT(server->ioc));
+ object_ref(OBJECT(sioc));
+ 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) {
+ return;
+ }
+
+ if (server->sioc) {
+ close_client(server);
+ object_unref(OBJECT(server->sioc));
+ }
+
+ if (server->listener) {
+ qio_net_listener_disconnect(server->listener);
+ object_unref(OBJECT(server->listener));
+ }
+}
+
+static void detach_context(VuServer *server)
+{
+ int i;
+ AioContext *ctx = server->ioc->ctx;
+ qio_channel_detach_aio_context(server->ioc);
+ for (i = 0; i < server->vu_dev.max_queues; i++) {
+ if (server->kick_info[i].cb) {
+ aio_set_fd_handler(ctx, server->kick_info[i].fd, false, NULL,
+ NULL, NULL, NULL);
+ }
+ }
+}
+
+static void attach_context(VuServer *server, AioContext *ctx)
+{
+ int i;
+ qio_channel_attach_aio_context(server->ioc, ctx);
+ server->aio_context_changed = true;
+ if (server->co_trip) {
+ aio_co_schedule(ctx, server->co_trip);
+ }
+ for (i = 0; i < server->vu_dev.max_queues; i++) {
+ if (server->kick_info[i].cb) {
+ aio_set_fd_handler(ctx, server->kick_info[i].fd, false,
+ kick_handler, NULL, NULL,
+ &server->kick_info[i]);
+ }
+ }
+}
+
+void vhost_user_server_set_aio_context(AioContext *ctx, VuServer *server)
+{
+ server->ctx = ctx ? ctx : qemu_get_aio_context();
+ if (!server->sioc) {
+ return;
+ }
+ if (ctx) {
+ attach_context(server, ctx);
+ } else {
+ detach_context(server);
+ }
+}
+
+
+bool vhost_user_server_start(uint16_t max_queues,
+ SocketAddress *socket_addr,
+ AioContext *ctx,
+ VuServer *server,
+ void *device_panic_notifier,
+ const VuDevIface *vu_iface,
+ Error **errp)
+{
+ 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);
+
+ return true;
+error:
+ g_free(server);
+ return false;
+}
diff --git a/util/vhost-user-server.h b/util/vhost-user-server.h
new file mode 100644
index 0000000000..4315556b66
--- /dev/null
+++ b/util/vhost-user-server.h
@@ -0,0 +1,59 @@
+/*
+ * 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.
+ */
+
+#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 KickInfo {
+ VuDev *vu_dev;
+ int fd; /*kick fd*/
+ long index; /*queue index*/
+ vu_watch_cb cb;
+} KickInfo;
+
+typedef struct VuServer {
+ QIONetListener *listener;
+ AioContext *ctx;
+ void (*device_panic_notifier)(struct VuServer *server) ;
+ 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 */
+ KickInfo *kick_info; /* an array with the length of the queue number */
+ /* restart coroutine co_trip if AIOContext is changed */
+ bool aio_context_changed;
+} VuServer;
+
+
+bool vhost_user_server_start(uint16_t max_queues,
+ SocketAddress *unix_socket,
+ AioContext *ctx,
+ VuServer *server,
+ 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);
+
+#endif /* VHOST_USER_SERVER_H */
--
2.26.2
