diff options
Diffstat (limited to 'qemu/hw/block/virtio-blk.c')
| -rw-r--r-- | qemu/hw/block/virtio-blk.c | 1012 |
1 files changed, 1012 insertions, 0 deletions
diff --git a/qemu/hw/block/virtio-blk.c b/qemu/hw/block/virtio-blk.c new file mode 100644 index 000000000..1556c9cf5 --- /dev/null +++ b/qemu/hw/block/virtio-blk.c @@ -0,0 +1,1012 @@ +/* + * Virtio Block Device + * + * Copyright IBM, Corp. 2007 + * + * Authors: + * Anthony Liguori <aliguori@us.ibm.com> + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + * + */ + +#include "qemu-common.h" +#include "qemu/iov.h" +#include "qemu/error-report.h" +#include "trace.h" +#include "hw/block/block.h" +#include "sysemu/block-backend.h" +#include "sysemu/blockdev.h" +#include "hw/virtio/virtio-blk.h" +#include "dataplane/virtio-blk.h" +#include "migration/migration.h" +#include "block/scsi.h" +#ifdef __linux__ +# include <scsi/sg.h> +#endif +#include "hw/virtio/virtio-bus.h" +#include "hw/virtio/virtio-access.h" + +VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s) +{ + VirtIOBlockReq *req = g_slice_new(VirtIOBlockReq); + req->dev = s; + req->qiov.size = 0; + req->in_len = 0; + req->next = NULL; + req->mr_next = NULL; + return req; +} + +void virtio_blk_free_request(VirtIOBlockReq *req) +{ + if (req) { + g_slice_free(VirtIOBlockReq, req); + } +} + +static void virtio_blk_complete_request(VirtIOBlockReq *req, + unsigned char status) +{ + VirtIOBlock *s = req->dev; + VirtIODevice *vdev = VIRTIO_DEVICE(s); + + trace_virtio_blk_req_complete(req, status); + + stb_p(&req->in->status, status); + virtqueue_push(s->vq, &req->elem, req->in_len); + virtio_notify(vdev, s->vq); +} + +static void virtio_blk_req_complete(VirtIOBlockReq *req, unsigned char status) +{ + req->dev->complete_request(req, status); +} + +static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error, + bool is_read) +{ + BlockErrorAction action = blk_get_error_action(req->dev->blk, + is_read, error); + VirtIOBlock *s = req->dev; + + if (action == BLOCK_ERROR_ACTION_STOP) { + req->next = s->rq; + s->rq = req; + } else if (action == BLOCK_ERROR_ACTION_REPORT) { + virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); + block_acct_done(blk_get_stats(s->blk), &req->acct); + virtio_blk_free_request(req); + } + + blk_error_action(s->blk, action, is_read, error); + return action != BLOCK_ERROR_ACTION_IGNORE; +} + +static void virtio_blk_rw_complete(void *opaque, int ret) +{ + VirtIOBlockReq *next = opaque; + + while (next) { + VirtIOBlockReq *req = next; + next = req->mr_next; + trace_virtio_blk_rw_complete(req, ret); + + if (req->qiov.nalloc != -1) { + /* If nalloc is != 1 req->qiov is a local copy of the original + * external iovec. It was allocated in submit_merged_requests + * to be able to merge requests. */ + qemu_iovec_destroy(&req->qiov); + } + + if (ret) { + int p = virtio_ldl_p(VIRTIO_DEVICE(req->dev), &req->out.type); + bool is_read = !(p & VIRTIO_BLK_T_OUT); + /* Note that memory may be dirtied on read failure. If the + * virtio request is not completed here, as is the case for + * BLOCK_ERROR_ACTION_STOP, the memory may not be copied + * correctly during live migration. While this is ugly, + * it is acceptable because the device is free to write to + * the memory until the request is completed (which will + * happen on the other side of the migration). + */ + if (virtio_blk_handle_rw_error(req, -ret, is_read)) { + continue; + } + } + + virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); + block_acct_done(blk_get_stats(req->dev->blk), &req->acct); + virtio_blk_free_request(req); + } +} + +static void virtio_blk_flush_complete(void *opaque, int ret) +{ + VirtIOBlockReq *req = opaque; + + if (ret) { + if (virtio_blk_handle_rw_error(req, -ret, 0)) { + return; + } + } + + virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); + block_acct_done(blk_get_stats(req->dev->blk), &req->acct); + virtio_blk_free_request(req); +} + +#ifdef __linux__ + +typedef struct { + VirtIOBlockReq *req; + struct sg_io_hdr hdr; +} VirtIOBlockIoctlReq; + +static void virtio_blk_ioctl_complete(void *opaque, int status) +{ + VirtIOBlockIoctlReq *ioctl_req = opaque; + VirtIOBlockReq *req = ioctl_req->req; + VirtIODevice *vdev = VIRTIO_DEVICE(req->dev); + struct virtio_scsi_inhdr *scsi; + struct sg_io_hdr *hdr; + + scsi = (void *)req->elem.in_sg[req->elem.in_num - 2].iov_base; + + if (status) { + status = VIRTIO_BLK_S_UNSUPP; + virtio_stl_p(vdev, &scsi->errors, 255); + goto out; + } + + hdr = &ioctl_req->hdr; + /* + * From SCSI-Generic-HOWTO: "Some lower level drivers (e.g. ide-scsi) + * clear the masked_status field [hence status gets cleared too, see + * block/scsi_ioctl.c] even when a CHECK_CONDITION or COMMAND_TERMINATED + * status has occurred. However they do set DRIVER_SENSE in driver_status + * field. Also a (sb_len_wr > 0) indicates there is a sense buffer. + */ + if (hdr->status == 0 && hdr->sb_len_wr > 0) { + hdr->status = CHECK_CONDITION; + } + + virtio_stl_p(vdev, &scsi->errors, + hdr->status | (hdr->msg_status << 8) | + (hdr->host_status << 16) | (hdr->driver_status << 24)); + virtio_stl_p(vdev, &scsi->residual, hdr->resid); + virtio_stl_p(vdev, &scsi->sense_len, hdr->sb_len_wr); + virtio_stl_p(vdev, &scsi->data_len, hdr->dxfer_len); + +out: + virtio_blk_req_complete(req, status); + virtio_blk_free_request(req); + g_free(ioctl_req); +} + +#endif + +static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s) +{ + VirtIOBlockReq *req = virtio_blk_alloc_request(s); + + if (!virtqueue_pop(s->vq, &req->elem)) { + virtio_blk_free_request(req); + return NULL; + } + + return req; +} + +static int virtio_blk_handle_scsi_req(VirtIOBlockReq *req) +{ + int status = VIRTIO_BLK_S_OK; + struct virtio_scsi_inhdr *scsi = NULL; + VirtIODevice *vdev = VIRTIO_DEVICE(req->dev); + VirtQueueElement *elem = &req->elem; + VirtIOBlock *blk = req->dev; + +#ifdef __linux__ + int i; + VirtIOBlockIoctlReq *ioctl_req; + BlockAIOCB *acb; +#endif + + /* + * We require at least one output segment each for the virtio_blk_outhdr + * and the SCSI command block. + * + * We also at least require the virtio_blk_inhdr, the virtio_scsi_inhdr + * and the sense buffer pointer in the input segments. + */ + if (elem->out_num < 2 || elem->in_num < 3) { + status = VIRTIO_BLK_S_IOERR; + goto fail; + } + + /* + * The scsi inhdr is placed in the second-to-last input segment, just + * before the regular inhdr. + */ + scsi = (void *)elem->in_sg[elem->in_num - 2].iov_base; + + if (!blk->conf.scsi) { + status = VIRTIO_BLK_S_UNSUPP; + goto fail; + } + + /* + * No support for bidirection commands yet. + */ + if (elem->out_num > 2 && elem->in_num > 3) { + status = VIRTIO_BLK_S_UNSUPP; + goto fail; + } + +#ifdef __linux__ + ioctl_req = g_new0(VirtIOBlockIoctlReq, 1); + ioctl_req->req = req; + ioctl_req->hdr.interface_id = 'S'; + ioctl_req->hdr.cmd_len = elem->out_sg[1].iov_len; + ioctl_req->hdr.cmdp = elem->out_sg[1].iov_base; + ioctl_req->hdr.dxfer_len = 0; + + if (elem->out_num > 2) { + /* + * If there are more than the minimally required 2 output segments + * there is write payload starting from the third iovec. + */ + ioctl_req->hdr.dxfer_direction = SG_DXFER_TO_DEV; + ioctl_req->hdr.iovec_count = elem->out_num - 2; + + for (i = 0; i < ioctl_req->hdr.iovec_count; i++) { + ioctl_req->hdr.dxfer_len += elem->out_sg[i + 2].iov_len; + } + + ioctl_req->hdr.dxferp = elem->out_sg + 2; + + } else if (elem->in_num > 3) { + /* + * If we have more than 3 input segments the guest wants to actually + * read data. + */ + ioctl_req->hdr.dxfer_direction = SG_DXFER_FROM_DEV; + ioctl_req->hdr.iovec_count = elem->in_num - 3; + for (i = 0; i < ioctl_req->hdr.iovec_count; i++) { + ioctl_req->hdr.dxfer_len += elem->in_sg[i].iov_len; + } + + ioctl_req->hdr.dxferp = elem->in_sg; + } else { + /* + * Some SCSI commands don't actually transfer any data. + */ + ioctl_req->hdr.dxfer_direction = SG_DXFER_NONE; + } + + ioctl_req->hdr.sbp = elem->in_sg[elem->in_num - 3].iov_base; + ioctl_req->hdr.mx_sb_len = elem->in_sg[elem->in_num - 3].iov_len; + + acb = blk_aio_ioctl(blk->blk, SG_IO, &ioctl_req->hdr, + virtio_blk_ioctl_complete, ioctl_req); + if (!acb) { + g_free(ioctl_req); + status = VIRTIO_BLK_S_UNSUPP; + goto fail; + } + return -EINPROGRESS; +#else + abort(); +#endif + +fail: + /* Just put anything nonzero so that the ioctl fails in the guest. */ + if (scsi) { + virtio_stl_p(vdev, &scsi->errors, 255); + } + return status; +} + +static void virtio_blk_handle_scsi(VirtIOBlockReq *req) +{ + int status; + + status = virtio_blk_handle_scsi_req(req); + if (status != -EINPROGRESS) { + virtio_blk_req_complete(req, status); + virtio_blk_free_request(req); + } +} + +static inline void submit_requests(BlockBackend *blk, MultiReqBuffer *mrb, + int start, int num_reqs, int niov) +{ + QEMUIOVector *qiov = &mrb->reqs[start]->qiov; + int64_t sector_num = mrb->reqs[start]->sector_num; + int nb_sectors = mrb->reqs[start]->qiov.size / BDRV_SECTOR_SIZE; + bool is_write = mrb->is_write; + + if (num_reqs > 1) { + int i; + struct iovec *tmp_iov = qiov->iov; + int tmp_niov = qiov->niov; + + /* mrb->reqs[start]->qiov was initialized from external so we can't + * modifiy it here. We need to initialize it locally and then add the + * external iovecs. */ + qemu_iovec_init(qiov, niov); + + for (i = 0; i < tmp_niov; i++) { + qemu_iovec_add(qiov, tmp_iov[i].iov_base, tmp_iov[i].iov_len); + } + + for (i = start + 1; i < start + num_reqs; i++) { + qemu_iovec_concat(qiov, &mrb->reqs[i]->qiov, 0, + mrb->reqs[i]->qiov.size); + mrb->reqs[i - 1]->mr_next = mrb->reqs[i]; + nb_sectors += mrb->reqs[i]->qiov.size / BDRV_SECTOR_SIZE; + } + assert(nb_sectors == qiov->size / BDRV_SECTOR_SIZE); + + trace_virtio_blk_submit_multireq(mrb, start, num_reqs, sector_num, + nb_sectors, is_write); + block_acct_merge_done(blk_get_stats(blk), + is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ, + num_reqs - 1); + } + + if (is_write) { + blk_aio_writev(blk, sector_num, qiov, nb_sectors, + virtio_blk_rw_complete, mrb->reqs[start]); + } else { + blk_aio_readv(blk, sector_num, qiov, nb_sectors, + virtio_blk_rw_complete, mrb->reqs[start]); + } +} + +static int multireq_compare(const void *a, const void *b) +{ + const VirtIOBlockReq *req1 = *(VirtIOBlockReq **)a, + *req2 = *(VirtIOBlockReq **)b; + + /* + * Note that we can't simply subtract sector_num1 from sector_num2 + * here as that could overflow the return value. + */ + if (req1->sector_num > req2->sector_num) { + return 1; + } else if (req1->sector_num < req2->sector_num) { + return -1; + } else { + return 0; + } +} + +void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb) +{ + int i = 0, start = 0, num_reqs = 0, niov = 0, nb_sectors = 0; + int max_xfer_len = 0; + int64_t sector_num = 0; + + if (mrb->num_reqs == 1) { + submit_requests(blk, mrb, 0, 1, -1); + mrb->num_reqs = 0; + return; + } + + max_xfer_len = blk_get_max_transfer_length(mrb->reqs[0]->dev->blk); + max_xfer_len = MIN_NON_ZERO(max_xfer_len, BDRV_REQUEST_MAX_SECTORS); + + qsort(mrb->reqs, mrb->num_reqs, sizeof(*mrb->reqs), + &multireq_compare); + + for (i = 0; i < mrb->num_reqs; i++) { + VirtIOBlockReq *req = mrb->reqs[i]; + if (num_reqs > 0) { + bool merge = true; + + /* merge would exceed maximum number of IOVs */ + if (niov + req->qiov.niov > IOV_MAX) { + merge = false; + } + + /* merge would exceed maximum transfer length of backend device */ + if (req->qiov.size / BDRV_SECTOR_SIZE + nb_sectors > max_xfer_len) { + merge = false; + } + + /* requests are not sequential */ + if (sector_num + nb_sectors != req->sector_num) { + merge = false; + } + + if (!merge) { + submit_requests(blk, mrb, start, num_reqs, niov); + num_reqs = 0; + } + } + + if (num_reqs == 0) { + sector_num = req->sector_num; + nb_sectors = niov = 0; + start = i; + } + + nb_sectors += req->qiov.size / BDRV_SECTOR_SIZE; + niov += req->qiov.niov; + num_reqs++; + } + + submit_requests(blk, mrb, start, num_reqs, niov); + mrb->num_reqs = 0; +} + +static void virtio_blk_handle_flush(VirtIOBlockReq *req, MultiReqBuffer *mrb) +{ + block_acct_start(blk_get_stats(req->dev->blk), &req->acct, 0, + BLOCK_ACCT_FLUSH); + + /* + * Make sure all outstanding writes are posted to the backing device. + */ + if (mrb->is_write && mrb->num_reqs > 0) { + virtio_blk_submit_multireq(req->dev->blk, mrb); + } + blk_aio_flush(req->dev->blk, virtio_blk_flush_complete, req); +} + +static bool virtio_blk_sect_range_ok(VirtIOBlock *dev, + uint64_t sector, size_t size) +{ + uint64_t nb_sectors = size >> BDRV_SECTOR_BITS; + uint64_t total_sectors; + + if (nb_sectors > BDRV_REQUEST_MAX_SECTORS) { + return false; + } + if (sector & dev->sector_mask) { + return false; + } + if (size % dev->conf.conf.logical_block_size) { + return false; + } + blk_get_geometry(dev->blk, &total_sectors); + if (sector > total_sectors || nb_sectors > total_sectors - sector) { + return false; + } + return true; +} + +void virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb) +{ + uint32_t type; + struct iovec *in_iov = req->elem.in_sg; + struct iovec *iov = req->elem.out_sg; + unsigned in_num = req->elem.in_num; + unsigned out_num = req->elem.out_num; + + if (req->elem.out_num < 1 || req->elem.in_num < 1) { + error_report("virtio-blk missing headers"); + exit(1); + } + + if (unlikely(iov_to_buf(iov, out_num, 0, &req->out, + sizeof(req->out)) != sizeof(req->out))) { + error_report("virtio-blk request outhdr too short"); + exit(1); + } + + iov_discard_front(&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"); + exit(1); + } + + /* We always touch the last byte, so just see how big in_iov is. */ + req->in_len = iov_size(in_iov, in_num); + 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 = virtio_ldl_p(VIRTIO_DEVICE(req->dev), &req->out.type); + + /* VIRTIO_BLK_T_OUT defines the command direction. VIRTIO_BLK_T_BARRIER + * is an optional flag. Although a guest should not send this flag if + * not negotiated we ignored it in the past. So keep ignoring it. */ + switch (type & ~(VIRTIO_BLK_T_OUT | VIRTIO_BLK_T_BARRIER)) { + case VIRTIO_BLK_T_IN: + { + bool is_write = type & VIRTIO_BLK_T_OUT; + req->sector_num = virtio_ldq_p(VIRTIO_DEVICE(req->dev), + &req->out.sector); + + if (is_write) { + qemu_iovec_init_external(&req->qiov, iov, out_num); + trace_virtio_blk_handle_write(req, req->sector_num, + req->qiov.size / BDRV_SECTOR_SIZE); + } else { + qemu_iovec_init_external(&req->qiov, in_iov, in_num); + trace_virtio_blk_handle_read(req, req->sector_num, + req->qiov.size / BDRV_SECTOR_SIZE); + } + + if (!virtio_blk_sect_range_ok(req->dev, req->sector_num, + req->qiov.size)) { + virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); + virtio_blk_free_request(req); + return; + } + + block_acct_start(blk_get_stats(req->dev->blk), + &req->acct, req->qiov.size, + is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ); + + /* merge would exceed maximum number of requests or IO direction + * changes */ + if (mrb->num_reqs > 0 && (mrb->num_reqs == VIRTIO_BLK_MAX_MERGE_REQS || + is_write != mrb->is_write || + !req->dev->conf.request_merging)) { + virtio_blk_submit_multireq(req->dev->blk, mrb); + } + + assert(mrb->num_reqs < VIRTIO_BLK_MAX_MERGE_REQS); + mrb->reqs[mrb->num_reqs++] = req; + mrb->is_write = is_write; + break; + } + case VIRTIO_BLK_T_FLUSH: + virtio_blk_handle_flush(req, mrb); + break; + case VIRTIO_BLK_T_SCSI_CMD: + virtio_blk_handle_scsi(req); + break; + case VIRTIO_BLK_T_GET_ID: + { + VirtIOBlock *s = req->dev; + + /* + * NB: per existing s/n string convention the string is + * terminated by '\0' only when shorter than buffer. + */ + const char *serial = s->conf.serial ? s->conf.serial : ""; + size_t size = MIN(strlen(serial) + 1, + MIN(iov_size(in_iov, in_num), + VIRTIO_BLK_ID_BYTES)); + iov_from_buf(in_iov, in_num, 0, serial, size); + virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); + virtio_blk_free_request(req); + break; + } + default: + virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP); + virtio_blk_free_request(req); + } +} + +static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq) +{ + VirtIOBlock *s = VIRTIO_BLK(vdev); + VirtIOBlockReq *req; + MultiReqBuffer mrb = {}; + + /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start + * dataplane here instead of waiting for .set_status(). + */ + if (s->dataplane) { + virtio_blk_data_plane_start(s->dataplane); + return; + } + + while ((req = virtio_blk_get_request(s))) { + virtio_blk_handle_request(req, &mrb); + } + + if (mrb.num_reqs) { + virtio_blk_submit_multireq(s->blk, &mrb); + } +} + +static void virtio_blk_dma_restart_bh(void *opaque) +{ + VirtIOBlock *s = opaque; + VirtIOBlockReq *req = s->rq; + MultiReqBuffer mrb = {}; + + qemu_bh_delete(s->bh); + s->bh = NULL; + + s->rq = NULL; + + while (req) { + VirtIOBlockReq *next = req->next; + virtio_blk_handle_request(req, &mrb); + req = next; + } + + if (mrb.num_reqs) { + virtio_blk_submit_multireq(s->blk, &mrb); + } +} + +static void virtio_blk_dma_restart_cb(void *opaque, int running, + RunState state) +{ + VirtIOBlock *s = opaque; + + if (!running) { + return; + } + + if (!s->bh) { + s->bh = aio_bh_new(blk_get_aio_context(s->conf.conf.blk), + virtio_blk_dma_restart_bh, s); + qemu_bh_schedule(s->bh); + } +} + +static void virtio_blk_reset(VirtIODevice *vdev) +{ + VirtIOBlock *s = VIRTIO_BLK(vdev); + AioContext *ctx; + + /* + * This should cancel pending requests, but can't do nicely until there + * are per-device request lists. + */ + ctx = blk_get_aio_context(s->blk); + aio_context_acquire(ctx); + blk_drain(s->blk); + + if (s->dataplane) { + virtio_blk_data_plane_stop(s->dataplane); + } + aio_context_release(ctx); + + blk_set_enable_write_cache(s->blk, s->original_wce); +} + +/* coalesce internal state, copy to pci i/o region 0 + */ +static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) +{ + VirtIOBlock *s = VIRTIO_BLK(vdev); + BlockConf *conf = &s->conf.conf; + struct virtio_blk_config blkcfg; + uint64_t capacity; + int blk_size = conf->logical_block_size; + + blk_get_geometry(s->blk, &capacity); + memset(&blkcfg, 0, sizeof(blkcfg)); + virtio_stq_p(vdev, &blkcfg.capacity, capacity); + virtio_stl_p(vdev, &blkcfg.seg_max, 128 - 2); + virtio_stw_p(vdev, &blkcfg.geometry.cylinders, conf->cyls); + virtio_stl_p(vdev, &blkcfg.blk_size, blk_size); + virtio_stw_p(vdev, &blkcfg.min_io_size, conf->min_io_size / blk_size); + virtio_stw_p(vdev, &blkcfg.opt_io_size, conf->opt_io_size / blk_size); + blkcfg.geometry.heads = conf->heads; + /* + * We must ensure that the block device capacity is a multiple of + * the logical block size. If that is not the case, let's use + * sector_mask to adopt the geometry to have a correct picture. + * For those devices where the capacity is ok for the given geometry + * we don't touch the sector value of the geometry, since some devices + * (like s390 dasd) need a specific value. Here the capacity is already + * cyls*heads*secs*blk_size and the sector value is not block size + * divided by 512 - instead it is the amount of blk_size blocks + * per track (cylinder). + */ + if (blk_getlength(s->blk) / conf->heads / conf->secs % blk_size) { + blkcfg.geometry.sectors = conf->secs & ~s->sector_mask; + } else { + blkcfg.geometry.sectors = conf->secs; + } + blkcfg.size_max = 0; + blkcfg.physical_block_exp = get_physical_block_exp(conf); + blkcfg.alignment_offset = 0; + blkcfg.wce = blk_enable_write_cache(s->blk); + memcpy(config, &blkcfg, sizeof(struct virtio_blk_config)); +} + +static void virtio_blk_set_config(VirtIODevice *vdev, const uint8_t *config) +{ + VirtIOBlock *s = VIRTIO_BLK(vdev); + struct virtio_blk_config blkcfg; + + memcpy(&blkcfg, config, sizeof(blkcfg)); + + aio_context_acquire(blk_get_aio_context(s->blk)); + blk_set_enable_write_cache(s->blk, blkcfg.wce != 0); + aio_context_release(blk_get_aio_context(s->blk)); +} + +static uint64_t virtio_blk_get_features(VirtIODevice *vdev, uint64_t features, + Error **errp) +{ + VirtIOBlock *s = VIRTIO_BLK(vdev); + + virtio_add_feature(&features, VIRTIO_BLK_F_SEG_MAX); + virtio_add_feature(&features, VIRTIO_BLK_F_GEOMETRY); + virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY); + virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE); + if (__virtio_has_feature(features, VIRTIO_F_VERSION_1)) { + if (s->conf.scsi) { + error_setg(errp, "Please set scsi=off for virtio-blk devices in order to use virtio 1.0"); + return 0; + } + } else { + virtio_clear_feature(&features, VIRTIO_F_ANY_LAYOUT); + virtio_add_feature(&features, VIRTIO_BLK_F_SCSI); + } + + if (s->conf.config_wce) { + virtio_add_feature(&features, VIRTIO_BLK_F_CONFIG_WCE); + } + if (blk_enable_write_cache(s->blk)) { + virtio_add_feature(&features, VIRTIO_BLK_F_WCE); + } + if (blk_is_read_only(s->blk)) { + virtio_add_feature(&features, VIRTIO_BLK_F_RO); + } + + return features; +} + +static void virtio_blk_set_status(VirtIODevice *vdev, uint8_t status) +{ + VirtIOBlock *s = VIRTIO_BLK(vdev); + + if (s->dataplane && !(status & (VIRTIO_CONFIG_S_DRIVER | + VIRTIO_CONFIG_S_DRIVER_OK))) { + virtio_blk_data_plane_stop(s->dataplane); + } + + if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) { + return; + } + + /* A guest that supports VIRTIO_BLK_F_CONFIG_WCE must be able to send + * cache flushes. Thus, the "auto writethrough" behavior is never + * necessary for guests that support the VIRTIO_BLK_F_CONFIG_WCE feature. + * Leaving it enabled would break the following sequence: + * + * Guest started with "-drive cache=writethrough" + * Guest sets status to 0 + * Guest sets DRIVER bit in status field + * Guest reads host features (WCE=0, CONFIG_WCE=1) + * Guest writes guest features (WCE=0, CONFIG_WCE=1) + * Guest writes 1 to the WCE configuration field (writeback mode) + * Guest sets DRIVER_OK bit in status field + * + * s->blk would erroneously be placed in writethrough mode. + */ + if (!virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) { + aio_context_acquire(blk_get_aio_context(s->blk)); + blk_set_enable_write_cache(s->blk, + virtio_has_feature(vdev, VIRTIO_BLK_F_WCE)); + aio_context_release(blk_get_aio_context(s->blk)); + } +} + +static void virtio_blk_save(QEMUFile *f, void *opaque) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(opaque); + + virtio_save(vdev, f); +} + +static void virtio_blk_save_device(VirtIODevice *vdev, QEMUFile *f) +{ + VirtIOBlock *s = VIRTIO_BLK(vdev); + VirtIOBlockReq *req = s->rq; + + while (req) { + qemu_put_sbyte(f, 1); + qemu_put_buffer(f, (unsigned char *)&req->elem, + sizeof(VirtQueueElement)); + req = req->next; + } + qemu_put_sbyte(f, 0); +} + +static int virtio_blk_load(QEMUFile *f, void *opaque, int version_id) +{ + VirtIOBlock *s = opaque; + VirtIODevice *vdev = VIRTIO_DEVICE(s); + + if (version_id != 2) + return -EINVAL; + + return virtio_load(vdev, f, version_id); +} + +static int virtio_blk_load_device(VirtIODevice *vdev, QEMUFile *f, + int version_id) +{ + VirtIOBlock *s = VIRTIO_BLK(vdev); + + while (qemu_get_sbyte(f)) { + VirtIOBlockReq *req = virtio_blk_alloc_request(s); + qemu_get_buffer(f, (unsigned char *)&req->elem, + sizeof(VirtQueueElement)); + req->next = s->rq; + s->rq = req; + + virtqueue_map_sg(req->elem.in_sg, req->elem.in_addr, + req->elem.in_num, 1); + virtqueue_map_sg(req->elem.out_sg, req->elem.out_addr, + req->elem.out_num, 0); + } + + return 0; +} + +static void virtio_blk_resize(void *opaque) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(opaque); + + virtio_notify_config(vdev); +} + +static const BlockDevOps virtio_block_ops = { + .resize_cb = virtio_blk_resize, +}; + +/* Disable dataplane thread during live migration since it does not + * update the dirty memory bitmap yet. + */ +static void virtio_blk_migration_state_changed(Notifier *notifier, void *data) +{ + VirtIOBlock *s = container_of(notifier, VirtIOBlock, + migration_state_notifier); + MigrationState *mig = data; + Error *err = NULL; + + if (migration_in_setup(mig)) { + if (!s->dataplane) { + return; + } + virtio_blk_data_plane_destroy(s->dataplane); + s->dataplane = NULL; + } else if (migration_has_finished(mig) || + migration_has_failed(mig)) { + if (s->dataplane) { + return; + } + blk_drain_all(); /* complete in-flight non-dataplane requests */ + virtio_blk_data_plane_create(VIRTIO_DEVICE(s), &s->conf, + &s->dataplane, &err); + if (err != NULL) { + error_report_err(err); + } + } +} + +static void virtio_blk_device_realize(DeviceState *dev, Error **errp) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VirtIOBlock *s = VIRTIO_BLK(dev); + VirtIOBlkConf *conf = &s->conf; + Error *err = NULL; + static int virtio_blk_id; + + if (!conf->conf.blk) { + error_setg(errp, "drive property not set"); + return; + } + if (!blk_is_inserted(conf->conf.blk)) { + error_setg(errp, "Device needs media, but drive is empty"); + return; + } + + blkconf_serial(&conf->conf, &conf->serial); + s->original_wce = blk_enable_write_cache(conf->conf.blk); + blkconf_geometry(&conf->conf, NULL, 65535, 255, 255, &err); + if (err) { + error_propagate(errp, err); + return; + } + blkconf_blocksizes(&conf->conf); + + virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK, + sizeof(struct virtio_blk_config)); + + s->blk = conf->conf.blk; + s->rq = NULL; + s->sector_mask = (s->conf.conf.logical_block_size / BDRV_SECTOR_SIZE) - 1; + + s->vq = virtio_add_queue(vdev, 128, virtio_blk_handle_output); + s->complete_request = virtio_blk_complete_request; + virtio_blk_data_plane_create(vdev, conf, &s->dataplane, &err); + if (err != NULL) { + error_propagate(errp, err); + virtio_cleanup(vdev); + return; + } + s->migration_state_notifier.notify = virtio_blk_migration_state_changed; + add_migration_state_change_notifier(&s->migration_state_notifier); + + s->change = qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s); + register_savevm(dev, "virtio-blk", virtio_blk_id++, 2, + virtio_blk_save, virtio_blk_load, s); + blk_set_dev_ops(s->blk, &virtio_block_ops, s); + blk_set_guest_block_size(s->blk, s->conf.conf.logical_block_size); + + blk_iostatus_enable(s->blk); +} + +static void virtio_blk_device_unrealize(DeviceState *dev, Error **errp) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VirtIOBlock *s = VIRTIO_BLK(dev); + + remove_migration_state_change_notifier(&s->migration_state_notifier); + virtio_blk_data_plane_destroy(s->dataplane); + s->dataplane = NULL; + qemu_del_vm_change_state_handler(s->change); + unregister_savevm(dev, "virtio-blk", s); + blockdev_mark_auto_del(s->blk); + virtio_cleanup(vdev); +} + +static void virtio_blk_instance_init(Object *obj) +{ + VirtIOBlock *s = VIRTIO_BLK(obj); + + object_property_add_link(obj, "iothread", TYPE_IOTHREAD, + (Object **)&s->conf.iothread, + qdev_prop_allow_set_link_before_realize, + OBJ_PROP_LINK_UNREF_ON_RELEASE, NULL); + device_add_bootindex_property(obj, &s->conf.conf.bootindex, + "bootindex", "/disk@0,0", + DEVICE(obj), NULL); +} + +static Property virtio_blk_properties[] = { + DEFINE_BLOCK_PROPERTIES(VirtIOBlock, conf.conf), + DEFINE_BLOCK_CHS_PROPERTIES(VirtIOBlock, conf.conf), + DEFINE_PROP_STRING("serial", VirtIOBlock, conf.serial), + DEFINE_PROP_BIT("config-wce", VirtIOBlock, conf.config_wce, 0, true), +#ifdef __linux__ + DEFINE_PROP_BIT("scsi", VirtIOBlock, conf.scsi, 0, true), +#endif + DEFINE_PROP_BIT("request-merging", VirtIOBlock, conf.request_merging, 0, + true), + DEFINE_PROP_BIT("x-data-plane", VirtIOBlock, conf.data_plane, 0, false), + DEFINE_PROP_END_OF_LIST(), +}; + +static void virtio_blk_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); + + dc->props = virtio_blk_properties; + set_bit(DEVICE_CATEGORY_STORAGE, dc->categories); + vdc->realize = virtio_blk_device_realize; + vdc->unrealize = virtio_blk_device_unrealize; + vdc->get_config = virtio_blk_update_config; + vdc->set_config = virtio_blk_set_config; + vdc->get_features = virtio_blk_get_features; + vdc->set_status = virtio_blk_set_status; + vdc->reset = virtio_blk_reset; + vdc->save = virtio_blk_save_device; + vdc->load = virtio_blk_load_device; +} + +static const TypeInfo virtio_device_info = { + .name = TYPE_VIRTIO_BLK, + .parent = TYPE_VIRTIO_DEVICE, + .instance_size = sizeof(VirtIOBlock), + .instance_init = virtio_blk_instance_init, + .class_init = virtio_blk_class_init, +}; + +static void virtio_register_types(void) +{ + type_register_static(&virtio_device_info); +} + +type_init(virtio_register_types) |