diff options
Diffstat (limited to 'hw/virtio/vhost-user.c')
| -rw-r--r-- | hw/virtio/vhost-user.c | 217 |
1 files changed, 138 insertions, 79 deletions
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index 2fdd5daf74..ded0c10453 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -16,6 +16,7 @@ #include "hw/virtio/virtio.h" #include "hw/virtio/virtio-net.h" #include "chardev/char-fe.h" +#include "io/channel-socket.h" #include "sysemu/kvm.h" #include "qemu/error-report.h" #include "qemu/main-loop.h" @@ -237,7 +238,8 @@ struct vhost_user { struct vhost_dev *dev; /* Shared between vhost devs of the same virtio device */ VhostUserState *user; - int slave_fd; + QIOChannel *slave_ioc; + GSource *slave_src; NotifierWithReturn postcopy_notifier; struct PostCopyFD postcopy_fd; uint64_t postcopy_client_bases[VHOST_USER_MAX_RAM_SLOTS]; @@ -294,15 +296,27 @@ static int vhost_user_read_header(struct vhost_dev *dev, VhostUserMsg *msg) return 0; } -static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg) +struct vhost_user_read_cb_data { + struct vhost_dev *dev; + VhostUserMsg *msg; + GMainLoop *loop; + int ret; +}; + +static gboolean vhost_user_read_cb(GIOChannel *source, GIOCondition condition, + gpointer opaque) { + struct vhost_user_read_cb_data *data = opaque; + struct vhost_dev *dev = data->dev; + VhostUserMsg *msg = data->msg; struct vhost_user *u = dev->opaque; CharBackend *chr = u->user->chr; uint8_t *p = (uint8_t *) msg; int r, size; if (vhost_user_read_header(dev, msg) < 0) { - return -1; + data->ret = -1; + goto end; } /* validate message size is sane */ @@ -310,7 +324,8 @@ static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg) error_report("Failed to read msg header." " Size %d exceeds the maximum %zu.", msg->hdr.size, VHOST_USER_PAYLOAD_SIZE); - return -1; + data->ret = -1; + goto end; } if (msg->hdr.size) { @@ -320,11 +335,84 @@ static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg) if (r != size) { error_report("Failed to read msg payload." " Read %d instead of %d.", r, msg->hdr.size); - return -1; + data->ret = -1; + goto end; } } - return 0; +end: + g_main_loop_quit(data->loop); + return G_SOURCE_REMOVE; +} + +static gboolean slave_read(QIOChannel *ioc, GIOCondition condition, + gpointer opaque); + +/* + * This updates the read handler to use a new event loop context. + * Event sources are removed from the previous context : this ensures + * that events detected in the previous context are purged. They will + * be re-detected and processed in the new context. + */ +static void slave_update_read_handler(struct vhost_dev *dev, + GMainContext *ctxt) +{ + struct vhost_user *u = dev->opaque; + + if (!u->slave_ioc) { + return; + } + + if (u->slave_src) { + g_source_destroy(u->slave_src); + g_source_unref(u->slave_src); + } + + u->slave_src = qio_channel_add_watch_source(u->slave_ioc, + G_IO_IN | G_IO_HUP, + slave_read, dev, NULL, + ctxt); +} + +static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg) +{ + struct vhost_user *u = dev->opaque; + CharBackend *chr = u->user->chr; + GMainContext *prev_ctxt = chr->chr->gcontext; + GMainContext *ctxt = g_main_context_new(); + GMainLoop *loop = g_main_loop_new(ctxt, FALSE); + struct vhost_user_read_cb_data data = { + .dev = dev, + .loop = loop, + .msg = msg, + .ret = 0 + }; + + /* + * We want to be able to monitor the slave channel fd while waiting + * for chr I/O. This requires an event loop, but we can't nest the + * one to which chr is currently attached : its fd handlers might not + * be prepared for re-entrancy. So we create a new one and switch chr + * to use it. + */ + slave_update_read_handler(dev, ctxt); + qemu_chr_be_update_read_handlers(chr->chr, ctxt); + qemu_chr_fe_add_watch(chr, G_IO_IN | G_IO_HUP, vhost_user_read_cb, &data); + + g_main_loop_run(loop); + + /* + * Restore the previous event loop context. This also destroys/recreates + * event sources : this guarantees that all pending events in the original + * context that have been processed by the nested loop are purged. + */ + qemu_chr_be_update_read_handlers(chr->chr, prev_ctxt); + slave_update_read_handler(dev, NULL); + + g_main_loop_unref(loop); + g_main_context_unref(ctxt); + + return data.ret; } static int process_message_reply(struct vhost_dev *dev, @@ -1392,56 +1480,39 @@ static int vhost_user_slave_handle_vring_host_notifier(struct vhost_dev *dev, return 0; } -static void slave_read(void *opaque) +static void close_slave_channel(struct vhost_user *u) +{ + g_source_destroy(u->slave_src); + g_source_unref(u->slave_src); + u->slave_src = NULL; + object_unref(OBJECT(u->slave_ioc)); + u->slave_ioc = NULL; +} + +static gboolean slave_read(QIOChannel *ioc, GIOCondition condition, + gpointer opaque) { struct vhost_dev *dev = opaque; struct vhost_user *u = dev->opaque; VhostUserHeader hdr = { 0, }; VhostUserPayload payload = { 0, }; - int size, ret = 0; + Error *local_err = NULL; + gboolean rc = G_SOURCE_CONTINUE; + int ret = 0; struct iovec iov; - struct msghdr msgh; - int fd[VHOST_USER_SLAVE_MAX_FDS]; - char control[CMSG_SPACE(sizeof(fd))]; - struct cmsghdr *cmsg; - int i, fdsize = 0; - - memset(&msgh, 0, sizeof(msgh)); - msgh.msg_iov = &iov; - msgh.msg_iovlen = 1; - msgh.msg_control = control; - msgh.msg_controllen = sizeof(control); - - memset(fd, -1, sizeof(fd)); + g_autofree int *fd = NULL; + size_t fdsize = 0; + int i; /* Read header */ iov.iov_base = &hdr; iov.iov_len = VHOST_USER_HDR_SIZE; - do { - size = recvmsg(u->slave_fd, &msgh, 0); - } while (size < 0 && (errno == EINTR || errno == EAGAIN)); - - if (size != VHOST_USER_HDR_SIZE) { - error_report("Failed to read from slave."); + if (qio_channel_readv_full_all(ioc, &iov, 1, &fd, &fdsize, &local_err)) { + error_report_err(local_err); goto err; } - if (msgh.msg_flags & MSG_CTRUNC) { - error_report("Truncated message."); - goto err; - } - - for (cmsg = CMSG_FIRSTHDR(&msgh); cmsg != NULL; - cmsg = CMSG_NXTHDR(&msgh, cmsg)) { - if (cmsg->cmsg_level == SOL_SOCKET && - cmsg->cmsg_type == SCM_RIGHTS) { - fdsize = cmsg->cmsg_len - CMSG_LEN(0); - memcpy(fd, CMSG_DATA(cmsg), fdsize); - break; - } - } - if (hdr.size > VHOST_USER_PAYLOAD_SIZE) { error_report("Failed to read msg header." " Size %d exceeds the maximum %zu.", hdr.size, @@ -1450,12 +1521,8 @@ static void slave_read(void *opaque) } /* Read payload */ - do { - size = read(u->slave_fd, &payload, hdr.size); - } while (size < 0 && (errno == EINTR || errno == EAGAIN)); - - if (size != hdr.size) { - error_report("Failed to read payload from slave."); + if (qio_channel_read_all(ioc, (char *) &payload, hdr.size, &local_err)) { + error_report_err(local_err); goto err; } @@ -1468,20 +1535,13 @@ static void slave_read(void *opaque) break; case VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG: ret = vhost_user_slave_handle_vring_host_notifier(dev, &payload.area, - fd[0]); + fd ? fd[0] : -1); break; default: error_report("Received unexpected msg type: %d.", hdr.request); ret = -EINVAL; } - /* Close the remaining file descriptors. */ - for (i = 0; i < fdsize; i++) { - if (fd[i] != -1) { - close(fd[i]); - } - } - /* * REPLY_ACK feature handling. Other reply types has to be managed * directly in their request handlers. @@ -1501,28 +1561,25 @@ static void slave_read(void *opaque) iovec[1].iov_base = &payload; iovec[1].iov_len = hdr.size; - do { - size = writev(u->slave_fd, iovec, ARRAY_SIZE(iovec)); - } while (size < 0 && (errno == EINTR || errno == EAGAIN)); - - if (size != VHOST_USER_HDR_SIZE + hdr.size) { - error_report("Failed to send msg reply to slave."); + if (qio_channel_writev_all(ioc, iovec, ARRAY_SIZE(iovec), &local_err)) { + error_report_err(local_err); goto err; } } - return; + goto fdcleanup; err: - qemu_set_fd_handler(u->slave_fd, NULL, NULL, NULL); - close(u->slave_fd); - u->slave_fd = -1; - for (i = 0; i < fdsize; i++) { - if (fd[i] != -1) { + close_slave_channel(u); + rc = G_SOURCE_REMOVE; + +fdcleanup: + if (fd) { + for (i = 0; i < fdsize; i++) { close(fd[i]); } } - return; + return rc; } static int vhost_setup_slave_channel(struct vhost_dev *dev) @@ -1535,6 +1592,8 @@ static int vhost_setup_slave_channel(struct vhost_dev *dev) int sv[2], ret = 0; bool reply_supported = virtio_has_feature(dev->protocol_features, VHOST_USER_PROTOCOL_F_REPLY_ACK); + Error *local_err = NULL; + QIOChannel *ioc; if (!virtio_has_feature(dev->protocol_features, VHOST_USER_PROTOCOL_F_SLAVE_REQ)) { @@ -1546,8 +1605,13 @@ static int vhost_setup_slave_channel(struct vhost_dev *dev) return -1; } - u->slave_fd = sv[0]; - qemu_set_fd_handler(u->slave_fd, slave_read, NULL, dev); + ioc = QIO_CHANNEL(qio_channel_socket_new_fd(sv[0], &local_err)); + if (!ioc) { + error_report_err(local_err); + return -1; + } + u->slave_ioc = ioc; + slave_update_read_handler(dev, NULL); if (reply_supported) { msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK; @@ -1565,9 +1629,7 @@ static int vhost_setup_slave_channel(struct vhost_dev *dev) out: close(sv[1]); if (ret) { - qemu_set_fd_handler(u->slave_fd, NULL, NULL, NULL); - close(u->slave_fd); - u->slave_fd = -1; + close_slave_channel(u); } return ret; @@ -1804,7 +1866,6 @@ static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque) u = g_new0(struct vhost_user, 1); u->user = opaque; - u->slave_fd = -1; u->dev = dev; dev->opaque = u; @@ -1919,10 +1980,8 @@ static int vhost_user_backend_cleanup(struct vhost_dev *dev) close(u->postcopy_fd.fd); u->postcopy_fd.handler = NULL; } - if (u->slave_fd >= 0) { - qemu_set_fd_handler(u->slave_fd, NULL, NULL, NULL); - close(u->slave_fd); - u->slave_fd = -1; + if (u->slave_ioc) { + close_slave_channel(u); } g_free(u->region_rb); u->region_rb = NULL; |