Re: [Qemu-devel] [PULL 40/96] virtio-scsi: use standard-headers

[Paolo Bonzini]

On 11/03/2015 09:31, Michael S. Tsirkin wrote:
> On Wed, Mar 11, 2015 at 03:14:16PM +0800, Fam Zheng wrote:
>> On Wed, 02/18 22:48, Michael S. Tsirkin wrote:
>>> Drop duplicated code.
>>>
>>> Signed-off-by: Michael S. Tsirkin <address@hidden>
>>> Acked-by: Paolo Bonzini <address@hidden>
>>
>> Michael, this breaks virtio-scsi-pci:
>>
>>     qemu-system-x86_64: wrong size for virtio-scsi headers
> 
> Testing this now.
> 
> diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
> index de2c739..25d96f3 100644
> --- a/include/hw/virtio/virtio-scsi.h
> +++ b/include/hw/virtio/virtio-scsi.h
> @@ -136,15 +136,15 @@ typedef struct VirtIOSCSIReq {
>      union {
>          struct {
>              VirtIOSCSICmdReq  cmd;
> -            uint8_t           cdb[];
>          } QEMU_PACKED;
>          VirtIOSCSICtrlTMFReq  tmf;
>          VirtIOSCSICtrlANReq   an;
>      } req;
>  } VirtIOSCSIReq;
>  
> -QEMU_BUILD_BUG_ON(offsetof(VirtIOSCSIReq, req.cdb) !=
> -                  offsetof(VirtIOSCSIReq, req.cmd) + 
> sizeof(VirtIOSCSICmdReq));
> +QEMU_BUILD_BUG_ON(offsetof(VirtIOSCSIReq, req.cmd.cdb) !=
> +                  offsetof(VirtIOSCSIReq, req.cmd) +
> +                  offsetof(VirtIOSCSICmdReq, cdb));

No, this is too ugly.  Can I just queue a revert?

Paolo

>  #define DEFINE_VIRTIO_SCSI_PROPERTIES(_state, _conf_field)                   
>   \
>      DEFINE_PROP_UINT32("num_queues", _state, _conf_field.num_queues, 1),     
>   \
> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
> index cfb52e8..52bc00c 100644
> --- a/hw/scsi/virtio-scsi.c
> +++ b/hw/scsi/virtio-scsi.c
> @@ -47,7 +47,8 @@ VirtIOSCSIReq *virtio_scsi_init_req(VirtIOSCSI *s, 
> VirtQueue *vq)
>      const size_t zero_skip = offsetof(VirtIOSCSIReq, elem)
>                               + sizeof(VirtQueueElement);
>  
> -    req = g_slice_alloc(sizeof(*req) + vs->cdb_size);
> +    req = g_slice_alloc(sizeof(*req) + MAX(vs->cdb_size, 
> VIRTIO_SCSI_CDB_SIZE) -
> +                        VIRTIO_SCSI_CDB_SIZE);
>      req->vq = vq;
>      req->dev = s;
>      qemu_sglist_init(&req->qsgl, DEVICE(s), 8, &address_space_memory);
> @@ -62,7 +63,8 @@ void virtio_scsi_free_req(VirtIOSCSIReq *req)
>  
>      qemu_iovec_destroy(&req->resp_iov);
>      qemu_sglist_destroy(&req->qsgl);
> -    g_slice_free1(sizeof(*req) + vs->cdb_size, req);
> +    g_slice_free1(sizeof(*req) + MAX(vs->cdb_size, VIRTIO_SCSI_CDB_SIZE) -
> +                        VIRTIO_SCSI_CDB_SIZE, req);
>  }
>  
>  static void virtio_scsi_complete_req(VirtIOSCSIReq *req)
> @@ -213,8 +215,10 @@ static void *virtio_scsi_load_request(QEMUFile *f, 
> SCSIRequest *sreq)
>      assert(req->elem.in_num <= ARRAY_SIZE(req->elem.in_sg));
>      assert(req->elem.out_num <= ARRAY_SIZE(req->elem.out_sg));
>  
> -    if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICmdReq) + vs->cdb_size,
> -                              sizeof(VirtIOSCSICmdResp) + vs->sense_size) < 
> 0) {
> +    if (virtio_scsi_parse_req(req, offsetof(VirtIOSCSICmdReq, cdb) +
> +                              vs->cdb_size,
> +                              offsetof(VirtIOSCSICmdResp, sense) +
> +                              vs->sense_size) < 0) {
>          error_report("invalid SCSI request migration data");
>          exit(1);
>      }
> @@ -439,7 +443,7 @@ static void virtio_scsi_complete_cmd_req(VirtIOSCSIReq 
> *req)
>      /* Sense data is not in req->resp and is copied separately
>       * in virtio_scsi_command_complete.
>       */
> -    req->resp_size = sizeof(VirtIOSCSICmdResp);
> +    req->resp_size = offsetof(VirtIOSCSICmdResp, sense);
>      virtio_scsi_complete_req(req);
>  }
>  
> @@ -462,8 +466,10 @@ static void virtio_scsi_command_complete(SCSIRequest *r, 
> uint32_t status,
>      } else {
>          req->resp.cmd.resid = 0;
>          sense_len = scsi_req_get_sense(r, sense, sizeof(sense));
> -        sense_len = MIN(sense_len, req->resp_iov.size - 
> sizeof(req->resp.cmd));
> -        qemu_iovec_from_buf(&req->resp_iov, sizeof(req->resp.cmd),
> +        sense_len = MIN(sense_len, req->resp_iov.size -
> +                        offsetof(typeof(req->resp.cmd), sense));
> +        qemu_iovec_from_buf(&req->resp_iov,
> +                            offsetof(typeof(req->resp.cmd), sense),
>                              sense, sense_len);
>          req->resp.cmd.sense_len = virtio_tswap32(vdev, sense_len);
>      }
> @@ -522,8 +528,10 @@ bool virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, 
> VirtIOSCSIReq *req)
>      SCSIDevice *d;
>      int rc;
>  
> -    rc = virtio_scsi_parse_req(req, sizeof(VirtIOSCSICmdReq) + vs->cdb_size,
> -                               sizeof(VirtIOSCSICmdResp) + vs->sense_size);
> +    rc = virtio_scsi_parse_req(req, offsetof(VirtIOSCSICmdReq, cdb) +
> +                               vs->cdb_size,
> +                               offsetof(VirtIOSCSICmdResp, sense) +
> +                               vs->sense_size);
>      if (rc < 0) {
>          if (rc == -ENOTSUP) {
>              virtio_scsi_fail_cmd_req(req);
> @@ -544,7 +552,7 @@ bool virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, 
> VirtIOSCSIReq *req)
>      }
>      req->sreq = scsi_req_new(d, req->req.cmd.tag,
>                               virtio_scsi_get_lun(req->req.cmd.lun),
> -                             req->req.cdb, req);
> +                             req->req.cmd.cdb, req);
>  
>      if (req->sreq->cmd.mode != SCSI_XFER_NONE
>          && (req->sreq->cmd.mode != req->mode ||
> 
>