Re: [Qemu-devel] SCSI Command support over VirtIO Block device

[Stefan Hajnoczi]

On Dec 13, 2010 5:14 AM, "अनुज" <address@hidden> wrote:
>
> Hi
>
> I am trying to implement VirtIO support for a proprietary OS. And It
> would be great if I am able to process SCSI commands over VirtIO Block
> device.
>
> I tried to execute INQUIRY command but the status returned is UNSUPPORTED.
> If anyone provide example VirtIO SCSI Command request structure for
> INQUIRY command as per VirtIO spec Appendix D would be a great help.
>
> And also, the paragraph from VirtIO spec - 0.8.9 is confusing for me :
>
> "Historically, devices assumed that the  fields type, ioprio and
> sector reside in
> a single, separate read-only buffer; the  fields errors, data_len, sense_len and
> residual reside in a single, separate write-only buffer; the sense
>  eld in a separate
> write-only buffer of size 96 bytes, by itself; the fields errors,
> data_len, sense_len
> and residual in a single write-only buffer; and the status field is a
> separate readonly
> buffer of size 1 byte, by itself."
>
> Here 'status field of buffer size 1 byte' is whether readonly or writeonly?

Writeonly

>
> I want to know from which version of Qemu-kvm supports processing of
> scsi commands over VirtIO block device as a backend.
> Although I checked the Host Feature fields in which VIRTIO_BLK_F_SCSI
> bit is set. I am using qemu-kvm version 0.12.3.

Make sure you have a scsi-generic block device in qemu-kvm, not just a regular file or physical block device. Open /dev/sg.

Look at hw/virtio-blk.c in qemu-kvm for host implementation details.

>
> --
> Anuj Aggarwal
>
>  .''`.
> : :Ⓐ :   # apt-get install hakuna-matata
> `. `'`
>    `-
>