Re: [PATCH] virtio-spec: add field for scsi command size

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Mar 14, 2013 at 07:39:18PM +0200, Michael S. Tsirkin wrote:
> On Thu, Mar 14, 2013 at 04:15:28PM +0100, Paolo Bonzini wrote:
> > Il 14/03/2013 12:10, Michael S. Tsirkin ha scritto:
> > > Add field for guest to specify command size for virtio-blk.
> > > 
> > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> 
> OK, but Rusty usually tweaks wording anyway.
> Rusty want to apply and make changes Paolo suggested yourself
> or want me to?

Ping. Rusty could you indicate your preference please?

> > > ---
> > >  virtio-spec.lyx | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++----
> > >  1 file changed, 78 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/virtio-spec.lyx b/virtio-spec.lyx
> > > index a8ce3f9..fea97ed 100644
> > > --- a/virtio-spec.lyx
> > > +++ b/virtio-spec.lyx
> > > @@ -5826,6 +5826,16 @@ VIRTIO_BLK_F_TOPOLOGY (10) Device exports information on optimal I/O alignment.
> > >  \change_inserted 1531152142 1341302349
> > >  VIRTIO_BLK_F_CONFIG_WCE (11) Device can toggle its cache between writeback
> > >   and writethrough modes.
> > > +\change_inserted 1986246365 1363257418
> > > +
> > > +\end_layout
> > > +
> > > +\begin_layout Description
> > > +
> > > +\change_inserted 1986246365 1363258629
> > > +VIRTIO_BLK_F_CMD_SIZE (12) cmd_size field is valid.
> > 
> > SCSI_CMD_SIZE and scsi_cmd_size please.
> > 
> > > +\change_inserted 1531152142 1341302349
> > > +
> > >  \end_layout
> > >  
> > >  \end_deeper
> > > @@ -5994,6 +6004,30 @@ struct virtio_blk_config {
> > >  \change_inserted 1531152142 1341301918
> > >  
> > >      u8 writeback;
> > > +\change_inserted 1986246365 1363257385
> > > +
> > > +\end_layout
> > > +
> > > +\begin_layout Plain Layout
> > > +
> > > +\change_inserted 1986246365 1363258610
> > > +
> > > +    u8 reserved[3];
> > > +\end_layout
> > > +
> > > +\begin_layout Plain Layout
> > > +
> > > +\change_inserted 1986246365 1363259147
> > > +
> > > +    // buffer length for cmd field in requests.
> > 
> > size of the cmd field in VIRTIO_BLK_T_SCSI_CMD requests.
> > 
> > > + reset value 0.
> > > +\end_layout
> > > +
> > > +\begin_layout Plain Layout
> > > +
> > > +\change_inserted 1986246365 1363257810
> > > +
> > > +    u32 cmd_size;
> > 
> > scsi_cmd_size
> > 
> > >  \change_unchanged
> > >  
> > >  \end_layout
> > > @@ -6085,6 +6119,21 @@ Until version 1.1, QEMU remained in writeback mode even after a guest announced
> > >  \end_inset
> > >  
> > >  .
> > > +\change_inserted 1986246365 1363258989
> > > +
> > > +\end_layout
> > > +
> > > +\begin_layout Enumerate
> > > +
> > > +\change_inserted 1986246365 1363259237
> > > +If VIRTIO_BLK_F_SCSI_CMD_SIZE is negotiated, Guest should set the desired
> > > + size for scsi commands to the 
> > 
> > If both VIRTIO_BLK_F_SCSI and VIRTIO_BLK_F_SCSI_CMD_SIZE are negotiated,
> > the driver should write a non-zero value to the scsi_cmd_size field
> > before sending a VIRTIO_BLK_T_SCSI_CMD request.
> > 
> > > +\emph on
> > > +cmd_size 
> > > +\emph default
> > > +field.
> > > +\change_unchanged
> > > +
> > >  \end_layout
> > >  
> > >  \begin_layout Section*
> > > @@ -6369,8 +6418,33 @@ cmd
> > >  \emph default
> > >   field is only present for scsi packet command requests, and indicates the
> > >   command to perform.
> > > - This field must reside in a single, separate read-only buffer; command
> > > - length can be derived from the length of this buffer.
> > > + 
> > > +\change_inserted 1986246365 1363258881
> > > +If VIRTIO_BLK_F_SCSI_CMD_SIZE feature bit is negotiated, Guest must set
> > > + the command length by writing it to the cmd_size field in configuration
> > > + space
> > 
> > If the VIRTIO_BLK_F_SCSI_CMD_SIZE feature bit is negotiated, the driver
> > should write the length of the cmd field to the scsi_cmd_size field of
> > the configuration space.
> > 
> > (please make sure bold and emphasis are consistent)
> > 
> > > +\begin_inset Foot
> > > +status open
> > > +
> > > +\begin_layout Plain Layout
> > > +
> > > +\change_inserted 1986246365 1363258931
> > > +Guest should always set cmd_size during initialization.
> > 
> > scsi_cmd_size
> > 
> > > +\change_unchanged
> > > +
> > > +\end_layout
> > > +
> > > +\end_inset
> > > +
> > > +.
> > > + If VIRTIO_BLK_F_SCSI_CMD_SIZE is not negotiated, 
> > > +\change_deleted 1986246365 1363258703
> > > +T
> > > +\change_inserted 1986246365 1363258703
> > > +t
> > > +\change_unchanged
> > > +his field must reside in a single, separate read-only buffer; command length
> > > + can be derived from the length of this buffer.
> > 
> > the command length...
> > 
> > >   
> > >  \end_layout
> > >  
> > > 
> > 
> > Thanks,
> > 
> > Paolo