Re: [SeaBIOS] usb-msc.c: TEST_UNIT_READY needs USB_DIR_OUT?

[Paolo Bonzini]

Il 15/03/2012 03:44, Peter Stuge ha scritto:
> Kevin O'Connor wrote:
> > Subject: [PATCH] Use OUT mode for all zero byte "scsi" transfers.
>
> ..
> > +++ b/src/blockcmd.c
> > @@ -35,6 +35,13 @@ cdb_cmd_data(struct disk_op_s *op, void *cdbcmd, u16 blocksize)
> >      }
> >  }
> >
> > +// Determine if the command is a request to pull data from the device
> > +int
> > +cdb_is_read(u8 *cdbcmd, u16 blocksize)
> > +{
> > return blocksize && cdbcmd[0] != CDB_CMD_WRITE_10;
> >
> > +}
>
> Suggest that this only evaluates commands, ..

blocksize == 0 identifies a command that has no DMA, so it's a good way
to catch all the problematic commands, in case more are added in the future.
> > diff --git a/src/usb-msc.c b/src/usb-msc.c
> > index dadb9ca..c53a1f5 100644
> > --- a/src/usb-msc.c
> > +++ b/src/usb-msc.c
> > @@ -77,13 +77,13 @@ usb_cmd_data(struct disk_op_s *op, void *cdbcmd, u16 blocksize)
> >      cbw.dCBWSignature = CBW_SIGNATURE;
> >      cbw.dCBWTag = 999; // XXX
> >      cbw.dCBWDataTransferLength = bytes;
> > cbw.bmCBWFlags = (cbw.CBWCB[0] == CDB_CMD_WRITE_10) ? USB_DIR_OUT : USB_DIR_IN;
> > cbw.bmCBWFlags = cdb_is_read(cdbcmd, blocksize) ? USB_DIR_IN : USB_DIR_OUT;
>
> ..and that blocksize is checked here:
>
> cbw.bmCBWFlags = cdb_is_read(&cbw) && blocksize ? USB_DIR_IN : USB_DIR_OUT;

That would duplicate the check in virtio-scsi too.
> > diff --git a/src/virtio-scsi.c b/src/virtio-scsi.c
> > index 3c59438..50339d7 100644
> > --- a/src/virtio-scsi.c
> > +++ b/src/virtio-scsi.c
> > @@ -31,7 +31,7 @@ struct virtio_lun_s {
> >
> > static int
> >  virtio_scsi_cmd(u16 ioaddr, struct vring_virtqueue *vq, struct disk_op_s *op,
> >            void *cdbcmd, u16 target, u16 lun, u32 len)
> >            void *cdbcmd, u16 target, u16 lun, u16 blocksize)
> >
> > {
> >      struct virtio_scsi_req_cmd req;
> >      struct virtio_scsi_resp_cmd resp;
> > @@ -44,7 +44,8 @@ virtio_scsi_cmd(u16 ioaddr, struct vring_virtqueue *vq, struct disk_op_s *op,
> >      req.lun[3] = (lun & 0xff);
> >      memcpy(req.cdb, cdbcmd, 16);
> > int datain = (req.cdb[0] != CDB_CMD_WRITE_10);
> > u32 len = op->count * blocksize;
> > int datain = cdb_is_read(cdbcmd, blocksize);
> > int data_idx = (datain ? 2 : 1);
> > int out_num = (datain ? 1 : 2);
> > int in_num = (len ? 3 : 2) - out_num;
> >
> > @@ -89,7 +90,7 @@ virtio_scsi_cmd_data(struct disk_op_s *op, void *cdbcmd, u16 blocksize)
> >      return virtio_scsi_cmd(GET_GLOBAL(vlun->ioaddr),
> >                             GET_GLOBAL(vlun->vq), op, cdbcmd,
> >                             GET_GLOBAL(vlun->target), GET_GLOBAL(vlun->lun),
> >                       blocksize * op->count);
> >                       blocksize);
> >
> > }
>
> This also seems to be an unrelated change?

virtio_scsi_cmd needs blocksize to pass it to cdb_is_read.  So it's related.

FWIW,

Acked-by: Paolo Bonzini

Paolo