static int execute_command(BlockBackend *blk,
SCSIGenericReq *r, int direction,
BlockCompletionFunc *complete)
{
r->io_header.interface_id = 'S';
r->io_header.dxfer_direction = direction;
r->io_header.dxferp = r->buf;
r->io_header.dxfer_len = r->buflen;
r->io_header.cmdp = r->req.cmd.buf;
r->io_header.cmd_len = r->req.cmd.len;
r->io_header.mx_sb_len = sizeof(r->req.sense);
r->io_header.sbp = r->req.sense;
r->io_header.timeout = MAX_UINT;
r->io_header.usr_ptr = r;
r->io_header.flags |= SG_FLAG_DIRECT_IO;
r->req.aiocb = blk_aio_ioctl(blk, SG_IO, &r->io_header, complete, r);
if (r->req.aiocb == NULL) {
return -EIO;
}
return 0;
}
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;
}