diff options
Diffstat (limited to 'hw/virtio/vhost-user.c')
| -rw-r--r-- | hw/virtio/vhost-user.c | 246 |
1 files changed, 126 insertions, 120 deletions
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index 68eb1f0c99..7b42ae8aae 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -264,11 +264,6 @@ struct scrub_regions { int fd_idx; }; -static bool ioeventfd_enabled(void) -{ - return !kvm_enabled() || kvm_eventfds_enabled(); -} - static int vhost_user_read_header(struct vhost_dev *dev, VhostUserMsg *msg) { struct vhost_user *u = dev->opaque; @@ -388,7 +383,7 @@ static int vhost_user_write(struct vhost_dev *dev, VhostUserMsg *msg, * operations such as configuring device memory mappings or issuing device * resets, which affect the whole device instead of individual VQs, * vhost-user messages should only be sent once. - * + * * Devices with multiple vhost_devs are given an associated dev->vq_index * so per_device requests are only sent if vq_index is 0. */ @@ -1073,9 +1068,95 @@ static int vhost_user_set_vring_endian(struct vhost_dev *dev, return vhost_user_write(dev, &msg, NULL, 0); } +static int vhost_user_get_u64(struct vhost_dev *dev, int request, uint64_t *u64) +{ + int ret; + VhostUserMsg msg = { + .hdr.request = request, + .hdr.flags = VHOST_USER_VERSION, + }; + + if (vhost_user_per_device_request(request) && dev->vq_index != 0) { + return 0; + } + + ret = vhost_user_write(dev, &msg, NULL, 0); + if (ret < 0) { + return ret; + } + + ret = vhost_user_read(dev, &msg); + if (ret < 0) { + return ret; + } + + if (msg.hdr.request != request) { + error_report("Received unexpected msg type. Expected %d received %d", + request, msg.hdr.request); + return -EPROTO; + } + + if (msg.hdr.size != sizeof(msg.payload.u64)) { + error_report("Received bad msg size."); + return -EPROTO; + } + + *u64 = msg.payload.u64; + + return 0; +} + +static int vhost_user_get_features(struct vhost_dev *dev, uint64_t *features) +{ + if (vhost_user_get_u64(dev, VHOST_USER_GET_FEATURES, features) < 0) { + return -EPROTO; + } + + return 0; +} + +/* Note: "msg->hdr.flags" may be modified. */ +static int vhost_user_write_sync(struct vhost_dev *dev, VhostUserMsg *msg, + bool wait_for_reply) +{ + int ret; + + if (wait_for_reply) { + bool reply_supported = virtio_has_feature(dev->protocol_features, + VHOST_USER_PROTOCOL_F_REPLY_ACK); + if (reply_supported) { + msg->hdr.flags |= VHOST_USER_NEED_REPLY_MASK; + } + } + + ret = vhost_user_write(dev, msg, NULL, 0); + if (ret < 0) { + return ret; + } + + if (wait_for_reply) { + uint64_t dummy; + + if (msg->hdr.flags & VHOST_USER_NEED_REPLY_MASK) { + return process_message_reply(dev, msg); + } + + /* + * We need to wait for a reply but the backend does not + * support replies for the command we just sent. + * Send VHOST_USER_GET_FEATURES which makes all backends + * send a reply. + */ + return vhost_user_get_features(dev, &dummy); + } + + return 0; +} + static int vhost_set_vring(struct vhost_dev *dev, unsigned long int request, - struct vhost_vring_state *ring) + struct vhost_vring_state *ring, + bool wait_for_reply) { VhostUserMsg msg = { .hdr.request = request, @@ -1084,13 +1165,13 @@ static int vhost_set_vring(struct vhost_dev *dev, .hdr.size = sizeof(msg.payload.state), }; - return vhost_user_write(dev, &msg, NULL, 0); + return vhost_user_write_sync(dev, &msg, wait_for_reply); } static int vhost_user_set_vring_num(struct vhost_dev *dev, struct vhost_vring_state *ring) { - return vhost_set_vring(dev, VHOST_USER_SET_VRING_NUM, ring); + return vhost_set_vring(dev, VHOST_USER_SET_VRING_NUM, ring, false); } static void vhost_user_host_notifier_free(VhostUserHostNotifier *n) @@ -1121,7 +1202,7 @@ static void vhost_user_host_notifier_remove(VhostUserHostNotifier *n, static int vhost_user_set_vring_base(struct vhost_dev *dev, struct vhost_vring_state *ring) { - return vhost_set_vring(dev, VHOST_USER_SET_VRING_BASE, ring); + return vhost_set_vring(dev, VHOST_USER_SET_VRING_BASE, ring, false); } static int vhost_user_set_vring_enable(struct vhost_dev *dev, int enable) @@ -1139,7 +1220,21 @@ static int vhost_user_set_vring_enable(struct vhost_dev *dev, int enable) .num = enable, }; - ret = vhost_set_vring(dev, VHOST_USER_SET_VRING_ENABLE, &state); + /* + * SET_VRING_ENABLE travels from guest to QEMU to vhost-user backend / + * control plane thread via unix domain socket. Virtio requests travel + * from guest to vhost-user backend / data plane thread via eventfd. + * Even if the guest enables the ring first, and pushes its first virtio + * request second (conforming to the virtio spec), the data plane thread + * in the backend may see the virtio request before the control plane + * thread sees the queue enablement. This causes (in fact, requires) the + * data plane thread to discard the virtio request (it arrived on a + * seemingly disabled queue). To prevent this out-of-order delivery, + * don't let the guest proceed to pushing the virtio request until the + * backend control plane acknowledges enabling the queue -- IOW, pass + * wait_for_reply=true below. + */ + ret = vhost_set_vring(dev, VHOST_USER_SET_VRING_ENABLE, &state, true); if (ret < 0) { /* * Restoring the previous state is likely infeasible, as well as @@ -1218,7 +1313,7 @@ static int vhost_set_vring_file(struct vhost_dev *dev, .hdr.size = sizeof(msg.payload.u64), }; - if (ioeventfd_enabled() && file->fd > 0) { + if (file->fd > 0) { fds[fd_num++] = file->fd; } else { msg.payload.u64 |= VHOST_USER_VRING_NOFD_MASK; @@ -1245,75 +1340,9 @@ static int vhost_user_set_vring_err(struct vhost_dev *dev, return vhost_set_vring_file(dev, VHOST_USER_SET_VRING_ERR, file); } -static int vhost_user_get_u64(struct vhost_dev *dev, int request, uint64_t *u64) -{ - int ret; - VhostUserMsg msg = { - .hdr.request = request, - .hdr.flags = VHOST_USER_VERSION, - }; - - if (vhost_user_per_device_request(request) && dev->vq_index != 0) { - return 0; - } - - ret = vhost_user_write(dev, &msg, NULL, 0); - if (ret < 0) { - return ret; - } - - ret = vhost_user_read(dev, &msg); - if (ret < 0) { - return ret; - } - - if (msg.hdr.request != request) { - error_report("Received unexpected msg type. Expected %d received %d", - request, msg.hdr.request); - return -EPROTO; - } - - if (msg.hdr.size != sizeof(msg.payload.u64)) { - error_report("Received bad msg size."); - return -EPROTO; - } - - *u64 = msg.payload.u64; - - return 0; -} - -static int vhost_user_get_features(struct vhost_dev *dev, uint64_t *features) -{ - if (vhost_user_get_u64(dev, VHOST_USER_GET_FEATURES, features) < 0) { - return -EPROTO; - } - - return 0; -} - -static int enforce_reply(struct vhost_dev *dev, - const VhostUserMsg *msg) -{ - uint64_t dummy; - - if (msg->hdr.flags & VHOST_USER_NEED_REPLY_MASK) { - return process_message_reply(dev, msg); - } - - /* - * We need to wait for a reply but the backend does not - * support replies for the command we just sent. - * Send VHOST_USER_GET_FEATURES which makes all backends - * send a reply. - */ - return vhost_user_get_features(dev, &dummy); -} - static int vhost_user_set_vring_addr(struct vhost_dev *dev, struct vhost_vring_addr *addr) { - int ret; VhostUserMsg msg = { .hdr.request = VHOST_USER_SET_VRING_ADDR, .hdr.flags = VHOST_USER_VERSION, @@ -1321,29 +1350,13 @@ static int vhost_user_set_vring_addr(struct vhost_dev *dev, .hdr.size = sizeof(msg.payload.addr), }; - bool reply_supported = virtio_has_feature(dev->protocol_features, - VHOST_USER_PROTOCOL_F_REPLY_ACK); - /* * wait for a reply if logging is enabled to make sure * backend is actually logging changes */ bool wait_for_reply = addr->flags & (1 << VHOST_VRING_F_LOG); - if (reply_supported && wait_for_reply) { - msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK; - } - - ret = vhost_user_write(dev, &msg, NULL, 0); - if (ret < 0) { - return ret; - } - - if (wait_for_reply) { - return enforce_reply(dev, &msg); - } - - return 0; + return vhost_user_write_sync(dev, &msg, wait_for_reply); } static int vhost_user_set_u64(struct vhost_dev *dev, int request, uint64_t u64, @@ -1355,26 +1368,8 @@ static int vhost_user_set_u64(struct vhost_dev *dev, int request, uint64_t u64, .payload.u64 = u64, .hdr.size = sizeof(msg.payload.u64), }; - int ret; - - if (wait_for_reply) { - bool reply_supported = virtio_has_feature(dev->protocol_features, - VHOST_USER_PROTOCOL_F_REPLY_ACK); - if (reply_supported) { - msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK; - } - } - - ret = vhost_user_write(dev, &msg, NULL, 0); - if (ret < 0) { - return ret; - } - if (wait_for_reply) { - return enforce_reply(dev, &msg); - } - - return 0; + return vhost_user_write_sync(dev, &msg, wait_for_reply); } static int vhost_user_set_status(struct vhost_dev *dev, uint8_t status) @@ -1482,12 +1477,17 @@ static int vhost_user_reset_device(struct vhost_dev *dev) { VhostUserMsg msg = { .hdr.flags = VHOST_USER_VERSION, + .hdr.request = VHOST_USER_RESET_DEVICE, }; - msg.hdr.request = virtio_has_feature(dev->protocol_features, - VHOST_USER_PROTOCOL_F_RESET_DEVICE) - ? VHOST_USER_RESET_DEVICE - : VHOST_USER_RESET_OWNER; + /* + * Historically, reset was not implemented so only reset devices + * that are expecting it. + */ + if (!virtio_has_feature(dev->protocol_features, + VHOST_USER_PROTOCOL_F_RESET_DEVICE)) { + return -ENOSYS; + } return vhost_user_write(dev, &msg, NULL, 0); } @@ -2751,6 +2751,7 @@ typedef struct { DeviceState *dev; CharBackend *cd; struct vhost_dev *vhost; + IOEventHandler *event_cb; } VhostAsyncCallback; static void vhost_user_async_close_bh(void *opaque) @@ -2765,7 +2766,10 @@ static void vhost_user_async_close_bh(void *opaque) */ if (vhost->vdev) { data->cb(data->dev); - } + } else if (data->event_cb) { + qemu_chr_fe_set_handlers(data->cd, NULL, NULL, data->event_cb, + NULL, data->dev, NULL, true); + } g_free(data); } @@ -2777,7 +2781,8 @@ static void vhost_user_async_close_bh(void *opaque) */ void vhost_user_async_close(DeviceState *d, CharBackend *chardev, struct vhost_dev *vhost, - vu_async_close_fn cb) + vu_async_close_fn cb, + IOEventHandler *event_cb) { if (!runstate_check(RUN_STATE_SHUTDOWN)) { /* @@ -2793,6 +2798,7 @@ void vhost_user_async_close(DeviceState *d, data->dev = d; data->cd = chardev; data->vhost = vhost; + data->event_cb = event_cb; /* Disable any further notifications on the chardev */ qemu_chr_fe_set_handlers(chardev, |