| /* |
| * 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 <sysemu.h> |
| #include "virtio-blk.h" |
| #include "block_int.h" |
| #ifdef __linux__ |
| # include <scsi/sg.h> |
| #endif |
| |
| typedef struct VirtIOBlock |
| { |
| VirtIODevice vdev; |
| BlockDriverState *bs; |
| VirtQueue *vq; |
| void *rq; |
| } VirtIOBlock; |
| |
| static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev) |
| { |
| return (VirtIOBlock *)vdev; |
| } |
| |
| typedef struct VirtIOBlockReq |
| { |
| VirtIOBlock *dev; |
| VirtQueueElement elem; |
| struct virtio_blk_inhdr *in; |
| struct virtio_blk_outhdr *out; |
| struct virtio_scsi_inhdr *scsi; |
| QEMUIOVector qiov; |
| struct VirtIOBlockReq *next; |
| } VirtIOBlockReq; |
| |
| static void virtio_blk_req_complete(VirtIOBlockReq *req, int status) |
| { |
| VirtIOBlock *s = req->dev; |
| |
| req->in->status = status; |
| virtqueue_push(s->vq, &req->elem, req->qiov.size + sizeof(*req->in)); |
| virtio_notify(&s->vdev, s->vq); |
| |
| qemu_free(req); |
| } |
| |
| static int virtio_blk_handle_write_error(VirtIOBlockReq *req, int error) |
| { |
| BlockInterfaceErrorAction action = drive_get_onerror(req->dev->bs); |
| VirtIOBlock *s = req->dev; |
| |
| if (action == BLOCK_ERR_IGNORE) |
| return 0; |
| |
| if ((error == ENOSPC && action == BLOCK_ERR_STOP_ENOSPC) |
| || action == BLOCK_ERR_STOP_ANY) { |
| req->next = s->rq; |
| s->rq = req; |
| vm_stop(0); |
| } else { |
| virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); |
| } |
| |
| return 1; |
| } |
| |
| static void virtio_blk_rw_complete(void *opaque, int ret) |
| { |
| VirtIOBlockReq *req = opaque; |
| |
| if (ret && (req->out->type & VIRTIO_BLK_T_OUT)) { |
| if (virtio_blk_handle_write_error(req, -ret)) |
| return; |
| } |
| |
| virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); |
| } |
| |
| static VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s) |
| { |
| VirtIOBlockReq *req = qemu_mallocz(sizeof(*req)); |
| req->dev = s; |
| return req; |
| } |
| |
| static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s) |
| { |
| VirtIOBlockReq *req = virtio_blk_alloc_request(s); |
| |
| if (req != NULL) { |
| if (!virtqueue_pop(s->vq, &req->elem)) { |
| qemu_free(req); |
| return NULL; |
| } |
| } |
| |
| return req; |
| } |
| |
| #ifdef __linux__ |
| static void virtio_blk_handle_scsi(VirtIOBlockReq *req) |
| { |
| struct sg_io_hdr hdr; |
| int ret, size = 0; |
| int status; |
| int i; |
| |
| /* |
| * 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 (req->elem.out_num < 2 || req->elem.in_num < 3) { |
| virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); |
| return; |
| } |
| |
| /* |
| * No support for bidirection commands yet. |
| */ |
| if (req->elem.out_num > 2 && req->elem.in_num > 3) { |
| virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP); |
| return; |
| } |
| |
| /* |
| * The scsi inhdr is placed in the second-to-last input segment, just |
| * before the regular inhdr. |
| */ |
| req->scsi = (void *)req->elem.in_sg[req->elem.in_num - 2].iov_base; |
| size = sizeof(*req->in) + sizeof(*req->scsi); |
| |
| memset(&hdr, 0, sizeof(struct sg_io_hdr)); |
| hdr.interface_id = 'S'; |
| hdr.cmd_len = req->elem.out_sg[1].iov_len; |
| hdr.cmdp = req->elem.out_sg[1].iov_base; |
| hdr.dxfer_len = 0; |
| |
| if (req->elem.out_num > 2) { |
| /* |
| * If there are more than the minimally required 2 output segments |
| * there is write payload starting from the third iovec. |
| */ |
| hdr.dxfer_direction = SG_DXFER_TO_DEV; |
| hdr.iovec_count = req->elem.out_num - 2; |
| |
| for (i = 0; i < hdr.iovec_count; i++) |
| hdr.dxfer_len += req->elem.out_sg[i + 2].iov_len; |
| |
| hdr.dxferp = req->elem.out_sg + 2; |
| |
| } else if (req->elem.in_num > 3) { |
| /* |
| * If we have more than 3 input segments the guest wants to actually |
| * read data. |
| */ |
| hdr.dxfer_direction = SG_DXFER_FROM_DEV; |
| hdr.iovec_count = req->elem.in_num - 3; |
| for (i = 0; i < hdr.iovec_count; i++) |
| hdr.dxfer_len += req->elem.in_sg[i].iov_len; |
| |
| hdr.dxferp = req->elem.in_sg; |
| size += hdr.dxfer_len; |
| } else { |
| /* |
| * Some SCSI commands don't actually transfer any data. |
| */ |
| hdr.dxfer_direction = SG_DXFER_NONE; |
| } |
| |
| hdr.sbp = req->elem.in_sg[req->elem.in_num - 3].iov_base; |
| hdr.mx_sb_len = req->elem.in_sg[req->elem.in_num - 3].iov_len; |
| size += hdr.mx_sb_len; |
| |
| ret = bdrv_ioctl(req->dev->bs, SG_IO, &hdr); |
| if (ret) { |
| status = VIRTIO_BLK_S_UNSUPP; |
| hdr.status = ret; |
| hdr.resid = hdr.dxfer_len; |
| } else if (hdr.status) { |
| status = VIRTIO_BLK_S_IOERR; |
| } else { |
| status = VIRTIO_BLK_S_OK; |
| } |
| |
| req->scsi->errors = hdr.status; |
| req->scsi->residual = hdr.resid; |
| req->scsi->sense_len = hdr.sb_len_wr; |
| req->scsi->data_len = hdr.dxfer_len; |
| |
| virtio_blk_req_complete(req, status); |
| } |
| #else |
| static void virtio_blk_handle_scsi(VirtIOBlockReq *req) |
| { |
| virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP); |
| } |
| #endif /* __linux__ */ |
| |
| static void virtio_blk_handle_write(VirtIOBlockReq *req) |
| { |
| bdrv_aio_writev(req->dev->bs, req->out->sector, &req->qiov, |
| req->qiov.size / 512, virtio_blk_rw_complete, req); |
| } |
| |
| static void virtio_blk_handle_read(VirtIOBlockReq *req) |
| { |
| bdrv_aio_readv(req->dev->bs, req->out->sector, &req->qiov, |
| req->qiov.size / 512, virtio_blk_rw_complete, req); |
| } |
| |
| static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq) |
| { |
| VirtIOBlock *s = to_virtio_blk(vdev); |
| VirtIOBlockReq *req; |
| |
| while ((req = virtio_blk_get_request(s))) { |
| if (req->elem.out_num < 1 || req->elem.in_num < 1) { |
| fprintf(stderr, "virtio-blk missing headers\n"); |
| exit(1); |
| } |
| |
| if (req->elem.out_sg[0].iov_len < sizeof(*req->out) || |
| req->elem.in_sg[req->elem.in_num - 1].iov_len < sizeof(*req->in)) { |
| fprintf(stderr, "virtio-blk header not in correct element\n"); |
| exit(1); |
| } |
| |
| req->out = (void *)req->elem.out_sg[0].iov_base; |
| req->in = (void *)req->elem.in_sg[req->elem.in_num - 1].iov_base; |
| |
| if (req->out->type & VIRTIO_BLK_T_SCSI_CMD) { |
| virtio_blk_handle_scsi(req); |
| } else if (req->out->type & VIRTIO_BLK_T_OUT) { |
| qemu_iovec_init_external(&req->qiov, &req->elem.out_sg[1], |
| req->elem.out_num - 1); |
| virtio_blk_handle_write(req); |
| } else { |
| qemu_iovec_init_external(&req->qiov, &req->elem.in_sg[0], |
| req->elem.in_num - 1); |
| virtio_blk_handle_read(req); |
| } |
| } |
| /* |
| * FIXME: Want to check for completions before returning to guest mode, |
| * so cached reads and writes are reported as quickly as possible. But |
| * that should be done in the generic block layer. |
| */ |
| } |
| |
| static void virtio_blk_dma_restart_cb(void *opaque, int running, int reason) |
| { |
| VirtIOBlock *s = opaque; |
| VirtIOBlockReq *req = s->rq; |
| |
| if (!running) |
| return; |
| |
| s->rq = NULL; |
| |
| while (req) { |
| virtio_blk_handle_write(req); |
| req = req->next; |
| } |
| } |
| |
| static void virtio_blk_reset(VirtIODevice *vdev) |
| { |
| /* |
| * This should cancel pending requests, but can't do nicely until there |
| * are per-device request lists. |
| */ |
| qemu_aio_flush(); |
| } |
| |
| static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) |
| { |
| VirtIOBlock *s = to_virtio_blk(vdev); |
| struct virtio_blk_config blkcfg; |
| uint64_t capacity; |
| int cylinders, heads, secs; |
| |
| bdrv_get_geometry(s->bs, &capacity); |
| bdrv_get_geometry_hint(s->bs, &cylinders, &heads, &secs); |
| stq_raw(&blkcfg.capacity, capacity); |
| stl_raw(&blkcfg.seg_max, 128 - 2); |
| stw_raw(&blkcfg.cylinders, cylinders); |
| blkcfg.heads = heads; |
| blkcfg.sectors = secs; |
| memcpy(config, &blkcfg, sizeof(blkcfg)); |
| } |
| |
| static uint32_t virtio_blk_get_features(VirtIODevice *vdev) |
| { |
| uint32_t features = 0; |
| |
| features |= (1 << VIRTIO_BLK_F_SEG_MAX); |
| features |= (1 << VIRTIO_BLK_F_GEOMETRY); |
| #ifdef __linux__ |
| features |= (1 << VIRTIO_BLK_F_SCSI); |
| #endif |
| |
| return features; |
| } |
| |
| static void virtio_blk_save(QEMUFile *f, void *opaque) |
| { |
| VirtIOBlock *s = opaque; |
| VirtIOBlockReq *req = s->rq; |
| |
| virtio_save(&s->vdev, f); |
| |
| while (req) { |
| qemu_put_sbyte(f, 1); |
| qemu_put_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem)); |
| req = req->next; |
| } |
| qemu_put_sbyte(f, 0); |
| } |
| |
| static int virtio_blk_load(QEMUFile *f, void *opaque, int version_id) |
| { |
| VirtIOBlock *s = opaque; |
| |
| if (version_id != 2) |
| return -EINVAL; |
| |
| virtio_load(&s->vdev, f); |
| while (qemu_get_sbyte(f)) { |
| VirtIOBlockReq *req = virtio_blk_alloc_request(s); |
| qemu_get_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem)); |
| req->next = s->rq; |
| s->rq = req->next; |
| } |
| |
| return 0; |
| } |
| |
| void *virtio_blk_init(PCIBus *bus, BlockDriverState *bs) |
| { |
| VirtIOBlock *s; |
| int cylinders, heads, secs; |
| static int virtio_blk_id; |
| |
| s = (VirtIOBlock *)virtio_init_pci(bus, "virtio-blk", |
| PCI_VENDOR_ID_REDHAT_QUMRANET, |
| PCI_DEVICE_ID_VIRTIO_BLOCK, |
| PCI_VENDOR_ID_REDHAT_QUMRANET, |
| VIRTIO_ID_BLOCK, |
| PCI_CLASS_STORAGE_OTHER, 0x00, |
| sizeof(struct virtio_blk_config), sizeof(VirtIOBlock)); |
| if (!s) |
| return NULL; |
| |
| s->vdev.get_config = virtio_blk_update_config; |
| s->vdev.get_features = virtio_blk_get_features; |
| s->vdev.reset = virtio_blk_reset; |
| s->bs = bs; |
| s->rq = NULL; |
| bs->private = &s->vdev.pci_dev; |
| bdrv_guess_geometry(s->bs, &cylinders, &heads, &secs); |
| bdrv_set_geometry_hint(s->bs, cylinders, heads, secs); |
| |
| s->vq = virtio_add_queue(&s->vdev, 128, virtio_blk_handle_output); |
| |
| qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s); |
| register_savevm("virtio-blk", virtio_blk_id++, 2, |
| virtio_blk_save, virtio_blk_load, s); |
| |
| return s; |
| } |