diff options
Diffstat (limited to 'block/export/vhost-user-blk-server.c')
| -rw-r--r-- | block/export/vhost-user-blk-server.c | 431 |
1 files changed, 431 insertions, 0 deletions
diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c new file mode 100644 index 0000000000..41f4933d6e --- /dev/null +++ b/block/export/vhost-user-blk-server.c @@ -0,0 +1,431 @@ +/* + * Sharing QEMU block devices via vhost-user protocal + * + * Parts of the code based on nbd/server.c. + * + * Copyright (c) Coiby Xu <coiby.xu@gmail.com>. + * 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 "block/block.h" +#include "contrib/libvhost-user/libvhost-user.h" +#include "standard-headers/linux/virtio_blk.h" +#include "qemu/vhost-user-server.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_NUM_QUEUES_DEFAULT = 1, +}; +struct virtio_blk_inhdr { + unsigned char status; +}; + +typedef struct VuBlkReq { + VuVirtqElement elem; + int64_t sector_num; + size_t size; + struct virtio_blk_inhdr *in; + struct virtio_blk_outhdr out; + VuServer *server; + struct VuVirtq *vq; +} VuBlkReq; + +/* vhost user block device */ +typedef struct { + BlockExport export; + VuServer vu_server; + uint32_t blk_size; + QIOChannelSocket *sioc; + struct virtio_blk_config blkcfg; + bool writable; +} VuBlkExport; + +static void vu_blk_req_complete(VuBlkReq *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); + + free(req); +} + +static int coroutine_fn +vu_blk_discard_write_zeroes(BlockBackend *blk, 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 %zd, expect %zu", size, sizeof(desc)); + return -EINVAL; + } + + 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(blk, range[0], range[1]) == 0) { + return 0; + } + } else if (type == VIRTIO_BLK_T_WRITE_ZEROES) { + if (blk_co_pwrite_zeroes(blk, range[0], range[1], 0) == 0) { + return 0; + } + } + + return -EINVAL; +} + +static void coroutine_fn vu_blk_virtio_process_req(void *opaque) +{ + VuBlkReq *req = opaque; + VuServer *server = req->server; + VuVirtqElement *elem = &req->elem; + uint32_t type; + + VuBlkExport *vexp = container_of(server, VuBlkExport, vu_server); + BlockBackend *blk = vexp->export.blk; + + 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"); + goto err; + } + + 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); + + if (is_write && !vexp->writable) { + req->in->status = VIRTIO_BLK_S_IOERR; + break; + } + + int64_t offset = req->sector_num * vexp->blk_size; + QEMUIOVector qiov; + if (is_write) { + qemu_iovec_init_external(&qiov, out_iov, out_num); + ret = blk_co_pwritev(blk, offset, qiov.size, &qiov, 0); + } else { + qemu_iovec_init_external(&qiov, in_iov, in_num); + ret = blk_co_preadv(blk, 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: + if (blk_co_flush(blk) == 0) { + req->in->status = VIRTIO_BLK_S_OK; + } else { + req->in->status = VIRTIO_BLK_S_IOERR; + } + 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"); + 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; + + if (!vexp->writable) { + req->in->status = VIRTIO_BLK_S_IOERR; + break; + } + + rc = vu_blk_discard_write_zeroes(blk, &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_blk_req_complete(req); + return; + +err: + free(req); +} + +static void vu_blk_process_vq(VuDev *vu_dev, int idx) +{ + VuServer *server = container_of(vu_dev, VuServer, vu_dev); + VuVirtq *vq = vu_get_queue(vu_dev, idx); + + while (1) { + VuBlkReq *req; + + req = vu_queue_pop(vu_dev, vq, sizeof(VuBlkReq)); + if (!req) { + break; + } + + req->server = server; + req->vq = vq; + + Coroutine *co = + qemu_coroutine_create(vu_blk_virtio_process_req, req); + qemu_coroutine_enter(co); + } +} + +static void vu_blk_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_blk_process_vq : NULL); +} + +static uint64_t vu_blk_get_features(VuDev *dev) +{ + uint64_t features; + VuServer *server = container_of(dev, VuServer, vu_dev); + VuBlkExport *vexp = container_of(server, VuBlkExport, vu_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_BLK_F_MQ | + 1ull << VIRTIO_F_VERSION_1 | + 1ull << VIRTIO_RING_F_INDIRECT_DESC | + 1ull << VIRTIO_RING_F_EVENT_IDX | + 1ull << VHOST_USER_F_PROTOCOL_FEATURES; + + if (!vexp->writable) { + features |= 1ull << VIRTIO_BLK_F_RO; + } + + return features; +} + +static uint64_t vu_blk_get_protocol_features(VuDev *dev) +{ + return 1ull << VHOST_USER_PROTOCOL_F_CONFIG | + 1ull << VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD; +} + +static int +vu_blk_get_config(VuDev *vu_dev, uint8_t *config, uint32_t len) +{ + /* TODO blkcfg must be little-endian for VIRTIO 1.0 */ + VuServer *server = container_of(vu_dev, VuServer, vu_dev); + VuBlkExport *vexp = container_of(server, VuBlkExport, vu_server); + memcpy(config, &vexp->blkcfg, len); + return 0; +} + +static int +vu_blk_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); + VuBlkExport *vexp = container_of(server, VuBlkExport, vu_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; + vexp->blkcfg.wce = wce; + blk_set_enable_write_cache(vexp->export.blk, 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_blk_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_blk_iface = { + .get_features = vu_blk_get_features, + .queue_set_started = vu_blk_queue_set_started, + .get_protocol_features = vu_blk_get_protocol_features, + .get_config = vu_blk_get_config, + .set_config = vu_blk_set_config, + .process_msg = vu_blk_process_msg, +}; + +static void blk_aio_attached(AioContext *ctx, void *opaque) +{ + VuBlkExport *vexp = opaque; + + vexp->export.ctx = ctx; + vhost_user_server_attach_aio_context(&vexp->vu_server, ctx); +} + +static void blk_aio_detach(void *opaque) +{ + VuBlkExport *vexp = opaque; + + vhost_user_server_detach_aio_context(&vexp->vu_server); + vexp->export.ctx = NULL; +} + +static void +vu_blk_initialize_config(BlockDriverState *bs, + struct virtio_blk_config *config, + uint32_t blk_size, + uint16_t num_queues) +{ + 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 = num_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 void vu_blk_exp_request_shutdown(BlockExport *exp) +{ + VuBlkExport *vexp = container_of(exp, VuBlkExport, export); + + vhost_user_server_stop(&vexp->vu_server); +} + +static int vu_blk_exp_create(BlockExport *exp, BlockExportOptions *opts, + Error **errp) +{ + VuBlkExport *vexp = container_of(exp, VuBlkExport, export); + BlockExportOptionsVhostUserBlk *vu_opts = &opts->u.vhost_user_blk; + Error *local_err = NULL; + uint64_t logical_block_size; + uint16_t num_queues = VHOST_USER_BLK_NUM_QUEUES_DEFAULT; + + vexp->writable = opts->writable; + vexp->blkcfg.wce = 0; + + if (vu_opts->has_logical_block_size) { + logical_block_size = vu_opts->logical_block_size; + } else { + logical_block_size = BDRV_SECTOR_SIZE; + } + check_block_size(exp->id, "logical-block-size", logical_block_size, + &local_err); + if (local_err) { + error_propagate(errp, local_err); + return -EINVAL; + } + vexp->blk_size = logical_block_size; + blk_set_guest_block_size(exp->blk, logical_block_size); + + if (vu_opts->has_num_queues) { + num_queues = vu_opts->num_queues; + } + if (num_queues == 0) { + error_setg(errp, "num-queues must be greater than 0"); + return -EINVAL; + } + + vu_blk_initialize_config(blk_bs(exp->blk), &vexp->blkcfg, + logical_block_size, num_queues); + + blk_add_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach, + vexp); + + if (!vhost_user_server_start(&vexp->vu_server, vu_opts->addr, exp->ctx, + num_queues, &vu_blk_iface, errp)) { + blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, + blk_aio_detach, vexp); + return -EADDRNOTAVAIL; + } + + return 0; +} + +static void vu_blk_exp_delete(BlockExport *exp) +{ + VuBlkExport *vexp = container_of(exp, VuBlkExport, export); + + blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach, + vexp); +} + +const BlockExportDriver blk_exp_vhost_user_blk = { + .type = BLOCK_EXPORT_TYPE_VHOST_USER_BLK, + .instance_size = sizeof(VuBlkExport), + .create = vu_blk_exp_create, + .delete = vu_blk_exp_delete, + .request_shutdown = vu_blk_exp_request_shutdown, +}; |