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Date: Mon, 27 Apr 2009 09:36:51 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: [Qemu-devel] Re: [PATCH] virtio-blk: add SGI_IO passthru support
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To: Christoph Hellwig <hch@lst.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>, Rusty Russell <rusty@rustcorp.com.au>, qemu-devel@nongnu.org, kvm@vger.kernel.org, Hannes Reinecke <hare@suse.de>

Christoph Hellwig wrote:
> [had the qemu list address wrong the first time, reply to this message,
>  not the previous if you were on Cc]
>
>
> Add support for SG_IO passthru (packet commands) to the virtio-blk
> backend.  Conceptually based on an older patch from Hannes Reinecke
> but largely rewritten to match the code structure and layering in
> virtio-blk.
>
> Note that currently we issue the hose SG_IO synchronously.  We could
> easily switch to async I/O, but that would required either bloating
> the VirtIOBlockReq by the size of struct sg_io_hdr or an additional
> memory allocation for each SG_IO request.
>
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
>   

So practically speaking, what can you do with this?  Should we be 
handling some SCSI cmds internally to QEMU (like eject operations) and 
supporting media=cdrom in -drive for if=virtio?

On a related topic, should we switch /dev/vdX to be /dev/sdX?

Regards,

Anthony Liguori