Re: [Qemu-devel] virtio scsi host draft specification, v2

[Avi Kivity <avi@redhat.com>]

On 05/20/2011 11:21 AM, Paolo Bonzini wrote:
> Hi all,
>
> here is the second version of the spec.  In the end I took the advice 
> of merging all requestq's into one.  The reason for this is that I 
> took a look at the vSCSI device and liked its approach of using SAM 
> 8-byte LUNs directly.  While it _is_ complex (and not yet done right 
> by QEMU---will send a patch for that), the scheme is actually quite 
> natural to implement and use, and supporting generic bus/target/LUN 
> topologies is good to have for passthrough, as well.
>
> I also added a few more features from SAM to avoid redefining the 
> structs in the future.
>
> Of course it may be that I'm completely wrong. :)  Please comment on 
> the spec!

> Virtqueues
>      0:control transmitq
>      1:control receiveq
>      2:requestq
>

Shouldn't we plan multiqueue for this from day 1?

> Requests have the following format:
>
>      struct virtio_scsi_req_cmd {
>          u8 lun[8];
>          u64 id;
>          u8 task_attr;
>          u8 prio;
>          u8 crn;
>          u32 num_dataout, num_datain;
>          char cdb[];
>          char data[][num_dataout+num_datain];
>          u8 sense[];
>          u32 sense_len;
>          u32 residual;
>          u16 status_qualifier;
>          u8 status;
>          u8 response;
>      };

flags? room for growth?

-- 
error compiling committee.c: too many arguments to function