Am 14.06.2020 um 20:39 hat Coiby Xu geschrieben: > By making use of libvhost-user, block device drive can be shared to > the connected vhost-user client. Only one client can connect to the > server one time. > > Since vhost-user-server needs a block drive to be created first, delay > the creation of this object. > > Signed-off-by: Coiby Xu <coiby...@gmail.com> > --- > block/Makefile.objs | 1 + > block/export/vhost-user-blk-server.c | 669 +++++++++++++++++++++++++++ > block/export/vhost-user-blk-server.h | 35 ++ > softmmu/vl.c | 4 + > 4 files changed, 709 insertions(+) > create mode 100644 block/export/vhost-user-blk-server.c > create mode 100644 block/export/vhost-user-blk-server.h > > diff --git a/block/Makefile.objs b/block/Makefile.objs > index 3635b6b4c1..0eb7eff470 100644 > --- a/block/Makefile.objs > +++ b/block/Makefile.objs > @@ -24,6 +24,7 @@ block-obj-y += throttle-groups.o > block-obj-$(CONFIG_LINUX) += nvme.o > > block-obj-y += nbd.o > +block-obj-$(CONFIG_LINUX) += export/vhost-user-blk-server.o > ../contrib/libvhost-user/libvhost-user.o > block-obj-$(CONFIG_SHEEPDOG) += sheepdog.o > block-obj-$(CONFIG_LIBISCSI) += iscsi.o > block-obj-$(if $(CONFIG_LIBISCSI),y,n) += iscsi-opts.o > diff --git a/block/export/vhost-user-blk-server.c > b/block/export/vhost-user-blk-server.c > new file mode 100644 > index 0000000000..bbf2ceaa9b > --- /dev/null > +++ b/block/export/vhost-user-blk-server.c > @@ -0,0 +1,669 @@ > +/* > + * Sharing QEMU block devices via vhost-user protocal > + * > + * 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 "block/block.h" > +#include "vhost-user-blk-server.h" > +#include "qapi/error.h" > +#include "qom/object_interfaces.h" > +#include "sysemu/block-backend.h" > +#include "util/block-helpers.h" > + > +enum { > + VHOST_USER_BLK_MAX_QUEUES = 1, > +}; > +struct virtio_blk_inhdr { > + unsigned char status; > +}; > + > + > +typedef struct VuBlockReq { > + VuVirtqElement *elem; > + int64_t sector_num; > + size_t size; > + struct virtio_blk_inhdr *in; > + struct virtio_blk_outhdr out; > + VuServer *server; > + struct VuVirtq *vq; > +} VuBlockReq; > + > + > +static void vu_block_req_complete(VuBlockReq *req) > +{ > + VuDev *vu_dev = &req->server->vu_dev; > + > + /* IO size with 1 extra status byte */ > + vu_queue_push(vu_dev, req->vq, req->elem, req->size + 1); > + vu_queue_notify(vu_dev, req->vq); > + > + if (req->elem) { > + free(req->elem); > + } > + > + g_free(req); > +} > + > +static VuBlockDev *get_vu_block_device_by_server(VuServer *server) > +{ > + return container_of(server, VuBlockDev, vu_server); > +} > + > +static int coroutine_fn > +vu_block_discard_write_zeroes(VuBlockReq *req, struct iovec *iov, > + uint32_t iovcnt, uint32_t type) > +{ > + struct virtio_blk_discard_write_zeroes desc; > + ssize_t size = iov_to_buf(iov, iovcnt, 0, &desc, sizeof(desc)); > + if (unlikely(size != sizeof(desc))) { > + error_report("Invalid size %ld, expect %ld", size, sizeof(desc)); > + return -EINVAL; > + } > + > + VuBlockDev *vdev_blk = get_vu_block_device_by_server(req->server); > + uint64_t range[2] = { le64_to_cpu(desc.sector) << 9, > + le32_to_cpu(desc.num_sectors) << 9 }; > + if (type == VIRTIO_BLK_T_DISCARD) { > + if (blk_co_pdiscard(vdev_blk->backend, range[0], range[1]) == 0) { > + return 0; > + } > + } else if (type == VIRTIO_BLK_T_WRITE_ZEROES) { > + if (blk_co_pwrite_zeroes(vdev_blk->backend, > + range[0], range[1], 0) == 0) { > + return 0; > + } > + } > + > + return -EINVAL; > +} > + > + > +static void coroutine_fn vu_block_flush(VuBlockReq *req) > +{ > + VuBlockDev *vdev_blk = get_vu_block_device_by_server(req->server); > + BlockBackend *backend = vdev_blk->backend; > + blk_co_flush(backend); > +} > + > + > +struct req_data { > + VuServer *server; > + VuVirtq *vq; > + VuVirtqElement *elem; > +}; > + > +static void coroutine_fn vu_block_virtio_process_req(void *opaque) > +{ > + struct req_data *data = opaque; > + VuServer *server = data->server; > + VuVirtq *vq = data->vq; > + VuVirtqElement *elem = data->elem; > + uint32_t type; > + VuBlockReq *req; > + > + VuBlockDev *vdev_blk = get_vu_block_device_by_server(server); > + BlockBackend *backend = vdev_blk->backend; > + > + struct iovec *in_iov = elem->in_sg; > + struct iovec *out_iov = elem->out_sg; > + unsigned in_num = elem->in_num; > + unsigned out_num = elem->out_num; > + /* refer to hw/block/virtio_blk.c */ > + if (elem->out_num < 1 || elem->in_num < 1) { > + error_report("virtio-blk request missing headers"); > + free(elem); > + return; > + } > + > + req = g_new0(VuBlockReq, 1); > + req->server = server; > + req->vq = vq; > + req->elem = elem; > + > + if (unlikely(iov_to_buf(out_iov, out_num, 0, &req->out, > + sizeof(req->out)) != sizeof(req->out))) { > + error_report("virtio-blk request outhdr too short"); > + goto err; > + } > + > + iov_discard_front(&out_iov, &out_num, sizeof(req->out)); > + > + if (in_iov[in_num - 1].iov_len < sizeof(struct virtio_blk_inhdr)) { > + error_report("virtio-blk request inhdr too short"); > + goto err; > + } > + > + /* We always touch the last byte, so just see how big in_iov is. */ > + req->in = (void *)in_iov[in_num - 1].iov_base > + + in_iov[in_num - 1].iov_len > + - sizeof(struct virtio_blk_inhdr); > + iov_discard_back(in_iov, &in_num, sizeof(struct virtio_blk_inhdr)); > + > + > + type = le32_to_cpu(req->out.type); > + switch (type & ~VIRTIO_BLK_T_BARRIER) { > + case VIRTIO_BLK_T_IN: > + case VIRTIO_BLK_T_OUT: { > + ssize_t ret = 0; > + bool is_write = type & VIRTIO_BLK_T_OUT; > + req->sector_num = le64_to_cpu(req->out.sector); > + > + int64_t offset = req->sector_num * vdev_blk->blk_size; > + QEMUIOVector qiov; > + if (is_write) { > + qemu_iovec_init_external(&qiov, out_iov, out_num); > + ret = blk_co_pwritev(backend, offset, qiov.size, > + &qiov, 0); > + } else { > + qemu_iovec_init_external(&qiov, in_iov, in_num); > + ret = blk_co_preadv(backend, offset, qiov.size, > + &qiov, 0); > + } > + if (ret >= 0) { > + req->in->status = VIRTIO_BLK_S_OK; > + } else { > + req->in->status = VIRTIO_BLK_S_IOERR; > + } > + break; > + } > + case VIRTIO_BLK_T_FLUSH: > + vu_block_flush(req); > + req->in->status = VIRTIO_BLK_S_OK; > + break; > + case VIRTIO_BLK_T_GET_ID: { > + size_t size = MIN(iov_size(&elem->in_sg[0], in_num), > + VIRTIO_BLK_ID_BYTES); > + snprintf(elem->in_sg[0].iov_base, size, "%s", > "vhost_user_blk_server"); > + req->in->status = VIRTIO_BLK_S_OK; > + req->size = elem->in_sg[0].iov_len; > + break; > + } > + case VIRTIO_BLK_T_DISCARD: > + case VIRTIO_BLK_T_WRITE_ZEROES: { > + int rc; > + rc = vu_block_discard_write_zeroes(req, &elem->out_sg[1], > + out_num, type); > + if (rc == 0) { > + req->in->status = VIRTIO_BLK_S_OK; > + } else { > + req->in->status = VIRTIO_BLK_S_IOERR; > + } > + break; > + } > + default: > + req->in->status = VIRTIO_BLK_S_UNSUPP; > + break; > + } > + > + vu_block_req_complete(req); > + return; > + > +err: > + free(elem); > + g_free(req); > + return; > +} > + > + > + > +static void vu_block_process_vq(VuDev *vu_dev, int idx) > +{ > + VuServer *server; > + VuVirtq *vq; > + > + server = container_of(vu_dev, VuServer, vu_dev); > + assert(server); > + > + vq = vu_get_queue(vu_dev, idx); > + assert(vq); > + VuVirtqElement *elem; > + while (1) { > + elem = vu_queue_pop(vu_dev, vq, sizeof(VuVirtqElement) + > + sizeof(VuBlockReq)); > + if (elem) { > + struct req_data req_data = { > + .server = server, > + .vq = vq, > + .elem = elem > + };
This is on the stack of the function. > + Coroutine *co = > qemu_coroutine_create(vu_block_virtio_process_req, > + &req_data); > + aio_co_enter(server->ioc->ctx, co); Therefore, this code is only correct, if co accesses the data only while the function has not returned yet. This function is called in the context of vu_dispatch(), which in turn is called from vu_client_trip(). So we already run in a coroutine. In this case, aio_co_enter() only schedules co to run after the current coroutine yields or terminates. In other words, this looks wrong to me because req_data will be accessed when it's long out of scope. I think we need to malloc it. > + } else { > + break; > + } > + } > +} > + > +static void vu_block_queue_set_started(VuDev *vu_dev, int idx, bool started) > +{ > + VuVirtq *vq; > + > + assert(vu_dev); > + > + vq = vu_get_queue(vu_dev, idx); > + vu_set_queue_handler(vu_dev, vq, started ? vu_block_process_vq : NULL); > +} > + > +static uint64_t vu_block_get_features(VuDev *dev) > +{ > + uint64_t features; > + VuServer *server = container_of(dev, VuServer, vu_dev); > + VuBlockDev *vdev_blk = get_vu_block_device_by_server(server); > + features = 1ull << VIRTIO_BLK_F_SIZE_MAX | > + 1ull << VIRTIO_BLK_F_SEG_MAX | > + 1ull << VIRTIO_BLK_F_TOPOLOGY | > + 1ull << VIRTIO_BLK_F_BLK_SIZE | > + 1ull << VIRTIO_BLK_F_FLUSH | > + 1ull << VIRTIO_BLK_F_DISCARD | > + 1ull << VIRTIO_BLK_F_WRITE_ZEROES | > + 1ull << VIRTIO_BLK_F_CONFIG_WCE | > + 1ull << VIRTIO_F_VERSION_1 | > + 1ull << VIRTIO_RING_F_INDIRECT_DESC | > + 1ull << VIRTIO_RING_F_EVENT_IDX | > + 1ull << VHOST_USER_F_PROTOCOL_FEATURES; > + > + if (!vdev_blk->writable) { > + features |= 1ull << VIRTIO_BLK_F_RO; > + } > + > + return features; > +} > + > +static uint64_t vu_block_get_protocol_features(VuDev *dev) > +{ > + return 1ull << VHOST_USER_PROTOCOL_F_CONFIG | > + 1ull << VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD; > +} > + > +static int > +vu_block_get_config(VuDev *vu_dev, uint8_t *config, uint32_t len) > +{ > + VuServer *server = container_of(vu_dev, VuServer, vu_dev); > + VuBlockDev *vdev_blk = get_vu_block_device_by_server(server); > + memcpy(config, &vdev_blk->blkcfg, len); > + > + return 0; > +} > + > +static int > +vu_block_set_config(VuDev *vu_dev, const uint8_t *data, > + uint32_t offset, uint32_t size, uint32_t flags) > +{ > + VuServer *server = container_of(vu_dev, VuServer, vu_dev); > + VuBlockDev *vdev_blk = get_vu_block_device_by_server(server); > + uint8_t wce; > + > + /* don't support live migration */ > + if (flags != VHOST_SET_CONFIG_TYPE_MASTER) { > + return -EINVAL; > + } > + > + > + if (offset != offsetof(struct virtio_blk_config, wce) || > + size != 1) { > + return -EINVAL; > + } > + > + wce = *data; > + if (wce == vdev_blk->blkcfg.wce) { > + /* Do nothing as same with old configuration */ > + return 0; > + } This check is unnecessary. Nothing bad happens if you set the same value again. > + vdev_blk->blkcfg.wce = wce; > + blk_set_enable_write_cache(vdev_blk->backend, wce); > + return 0; > +} > + > + > +/* > + * When the client disconnects, it sends a VHOST_USER_NONE request > + * and vu_process_message will simple call exit which cause the VM > + * to exit abruptly. > + * To avoid this issue, process VHOST_USER_NONE request ahead > + * of vu_process_message. > + * > + */ > +static int vu_block_process_msg(VuDev *dev, VhostUserMsg *vmsg, int > *do_reply) > +{ > + if (vmsg->request == VHOST_USER_NONE) { > + dev->panic(dev, "disconnect"); > + return true; > + } > + return false; > +} > + > + > +static const VuDevIface vu_block_iface = { > + .get_features = vu_block_get_features, > + .queue_set_started = vu_block_queue_set_started, > + .get_protocol_features = vu_block_get_protocol_features, > + .get_config = vu_block_get_config, > + .set_config = vu_block_set_config, > + .process_msg = vu_block_process_msg, > +}; > + > +static void blk_aio_attached(AioContext *ctx, void *opaque) > +{ > + VuBlockDev *vub_dev = opaque; > + aio_context_acquire(ctx); > + vhost_user_server_set_aio_context(ctx, &vub_dev->vu_server); > + aio_context_release(ctx); > +} > + > +static void blk_aio_detach(void *opaque) > +{ > + VuBlockDev *vub_dev = opaque; > + AioContext *ctx = vub_dev->vu_server.ctx; > + aio_context_acquire(ctx); > + vhost_user_server_set_aio_context(NULL, &vub_dev->vu_server); > + aio_context_release(ctx); > +} > + > + > +static void > +vu_block_initialize_config(BlockDriverState *bs, > + struct virtio_blk_config *config, uint32_t > blk_size) > +{ > + config->capacity = bdrv_getlength(bs) >> BDRV_SECTOR_BITS; > + config->blk_size = blk_size; > + config->size_max = 0; > + config->seg_max = 128 - 2; > + config->min_io_size = 1; > + config->opt_io_size = 1; > + config->num_queues = VHOST_USER_BLK_MAX_QUEUES; > + config->max_discard_sectors = 32768; > + config->max_discard_seg = 1; > + config->discard_sector_alignment = config->blk_size >> 9; > + config->max_write_zeroes_sectors = 32768; > + config->max_write_zeroes_seg = 1; > +} > + > + > +static VuBlockDev *vu_block_init(VuBlockDev *vu_block_device, Error **errp) > +{ > + > + BlockBackend *blk; > + Error *local_error = NULL; > + const char *node_name = vu_block_device->node_name; > + bool writable = vu_block_device->writable; > + /* > + * Don't allow resize while the vhost user server is running, > + * otherwise we don't care what happens with the node. > + */ I think this comment belong to the blk_new() below where the shared permissions are specified. > + uint64_t perm = BLK_PERM_CONSISTENT_READ; > + int ret; > + > + AioContext *ctx; > + > + BlockDriverState *bs = bdrv_lookup_bs(node_name, node_name, > &local_error); > + > + if (!bs) { > + error_propagate(errp, local_error); > + return NULL; > + } > + > + if (bdrv_is_read_only(bs)) { > + writable = false; > + } > + > + if (writable) { > + perm |= BLK_PERM_WRITE; > + } > + > + ctx = bdrv_get_aio_context(bs); > + aio_context_acquire(ctx); > + bdrv_invalidate_cache(bs, NULL); > + aio_context_release(ctx); > + > + blk = blk_new(bdrv_get_aio_context(bs), perm, > + BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | > + BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); > + ret = blk_insert_bs(blk, bs, errp); > + > + if (ret < 0) { > + goto fail; > + } > + > + blk_set_enable_write_cache(blk, false); > + > + blk_set_allow_aio_context_change(blk, true); > + > + vu_block_device->blkcfg.wce = 0; > + vu_block_device->backend = blk; > + if (!vu_block_device->blk_size) { > + vu_block_device->blk_size = BDRV_SECTOR_SIZE; > + } > + vu_block_device->blkcfg.blk_size = vu_block_device->blk_size; > + blk_set_guest_block_size(blk, vu_block_device->blk_size); > + vu_block_initialize_config(bs, &vu_block_device->blkcfg, > + vu_block_device->blk_size); > + return vu_block_device; > + > +fail: > + blk_unref(blk); > + return NULL; > +} > + > +static void vhost_user_blk_server_stop(VuBlockDev *vu_block_device) > +{ > + if (!vu_block_device) { > + return; > + } > + > + vhost_user_server_stop(&vu_block_device->vu_server); > + > + if (vu_block_device->backend) { > + blk_remove_aio_context_notifier(vu_block_device->backend, > blk_aio_attached, > + blk_aio_detach, vu_block_device); > + } > + > + blk_unref(vu_block_device->backend); > + > +} > + > + > +static void vhost_user_blk_server_start(VuBlockDev *vu_block_device, > + Error **errp) > +{ > + SocketAddress *addr = vu_block_device->addr; > + > + if (!vu_block_init(vu_block_device, errp)) { > + return; > + } > + > + AioContext *ctx = bdrv_get_aio_context(blk_bs(vu_block_device->backend)); Please move declarations to the top of the function. > + if (!vhost_user_server_start(&vu_block_device->vu_server, addr, ctx, > + VHOST_USER_BLK_MAX_QUEUES, > + NULL, &vu_block_iface, > + errp)) { > + goto error; > + } > + > + blk_add_aio_context_notifier(vu_block_device->backend, blk_aio_attached, > + blk_aio_detach, vu_block_device); > + vu_block_device->running = true; > + return; > + > + error: > + vhost_user_blk_server_stop(vu_block_device); vu_block_device hasn't been fully set up. You need to undo only vu_block_init(). You must not call vhost_user_server_stop(). > +} > + > +static bool vu_prop_modificable(VuBlockDev *vus, Error **errp) The word is "modifiable". > +{ > + if (vus->running) { > + error_setg(errp, "The property can't be modified " > + "while the server is running"); > + return false; The indentation is off here. > + } > + return true; > +} > +static void vu_set_node_name(Object *obj, const char *value, Error **errp) > +{ > + VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj); > + > + if (vus->node_name) { > + if (!vu_prop_modificable(vus, errp)) { > + return; > + } Why don't we need to check vu_prop_modificable() when the property isn't set yet? I assume it's because the server can't even be started without a node name, but it would be more obviously correct if the check were done unconditionally. > + g_free(vus->node_name); > + } > + > + vus->node_name = g_strdup(value); > +} > + > +static char *vu_get_node_name(Object *obj, Error **errp) > +{ > + VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj); > + return g_strdup(vus->node_name); > +} > + > + > +static void vu_set_unix_socket(Object *obj, const char *value, > + Error **errp) > +{ > + VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj); > + > + if (vus->addr) { > + if (!vu_prop_modificable(vus, errp)) { > + return; > + } Same here. > + g_free(vus->addr->u.q_unix.path); > + g_free(vus->addr); > + } > + > + SocketAddress *addr = g_new0(SocketAddress, 1); > + addr->type = SOCKET_ADDRESS_TYPE_UNIX; > + addr->u.q_unix.path = g_strdup(value); > + vus->addr = addr; > +} > + > +static char *vu_get_unix_socket(Object *obj, Error **errp) > +{ > + VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj); > + return g_strdup(vus->addr->u.q_unix.path); > +} > + > +static bool vu_get_block_writable(Object *obj, Error **errp) > +{ > + VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj); > + return vus->writable; > +} > + > +static void vu_set_block_writable(Object *obj, bool value, Error **errp) > +{ > + VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj); > + > + if (!vu_prop_modificable(vus, errp)) { > + return; > + } > + > + vus->writable = value; > +} > + > +static void vu_get_blk_size(Object *obj, Visitor *v, const char *name, > + void *opaque, Error **errp) > +{ > + VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj); > + uint32_t value = vus->blk_size; > + > + visit_type_uint32(v, name, &value, errp); > +} > + > +static void vu_set_blk_size(Object *obj, Visitor *v, const char *name, > + void *opaque, Error **errp) > +{ > + VuBlockDev *vus = VHOST_USER_BLK_SERVER(obj); > + > + Error *local_err = NULL; > + uint32_t value; > + > + if (!vu_prop_modificable(vus, errp)) { > + return; > + } > + > + visit_type_uint32(v, name, &value, &local_err); > + if (local_err) { > + goto out; > + } > + > + check_logical_block_size(object_get_typename(obj), name, value, > &local_err); > + if (local_err) { > + goto out; > + } > + > + vus->blk_size = value; > + > +out: > + error_propagate(errp, local_err); > + vus->blk_size = value; Surely you don't want to set the value here, when some check failed? > +} > + > + > +static void vhost_user_blk_server_instance_finalize(Object *obj) > +{ > + VuBlockDev *vub = VHOST_USER_BLK_SERVER(obj); > + > + vhost_user_blk_server_stop(vub); > +} > + > +static void vhost_user_blk_server_complete(UserCreatable *obj, Error **errp) > +{ > + Error *local_error = NULL; > + VuBlockDev *vub = VHOST_USER_BLK_SERVER(obj); > + > + vhost_user_blk_server_start(vub, &local_error); > + > + if (local_error) { > + error_propagate(errp, local_error); > + return; > + } If you don't do anything with local_error (which is named inconsistently with local_err used above), you can just directly pass errp to vhost_user_blk_server_start(). > +} > + > +static void vhost_user_blk_server_class_init(ObjectClass *klass, > + void *class_data) > +{ > + UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass); > + ucc->complete = vhost_user_blk_server_complete; > + > + object_class_property_add_bool(klass, "writable", > + vu_get_block_writable, > + vu_set_block_writable); > + > + object_class_property_add_str(klass, "node-name", > + vu_get_node_name, > + vu_set_node_name); > + > + object_class_property_add_str(klass, "unix-socket", > + vu_get_unix_socket, > + vu_set_unix_socket); > + > + object_class_property_add(klass, "logical-block-size", "uint32", > + vu_get_blk_size, vu_set_blk_size, > + NULL, NULL); > +} > + > +static const TypeInfo vhost_user_blk_server_info = { > + .name = TYPE_VHOST_USER_BLK_SERVER, > + .parent = TYPE_OBJECT, > + .instance_size = sizeof(VuBlockDev), > + .instance_finalize = vhost_user_blk_server_instance_finalize, > + .class_init = vhost_user_blk_server_class_init, > + .interfaces = (InterfaceInfo[]) { > + {TYPE_USER_CREATABLE}, > + {} > + }, > +}; > + > +static void vhost_user_blk_server_register_types(void) > +{ > + type_register_static(&vhost_user_blk_server_info); > +} > + Please remove the trailing empty line. Compared to the last version that I reviewed, this seems to get the architecture for concurrent requests right, which is an important improvement. I feel we're getting quite close to mergable now. Kevin