Re: [Qemu-devel] virtio block device and sysfs

[Marc Haber]

Hi,

On Mon, Mar 22, 2010 at 02:26:11AM -0400, john cooper wrote:
> This is a tad ironic as that is how this saga begun.  Namely stuffing
> 20 bytes of serial number string into the virtio-blk PCI config space
> on qemu's side and pushing it over to the guest driver.  I exposed this
> to the guest app via a new ioctl cmd which itself was the original
> point of contention.  Someone took issue with introducing a new
> interface citing the existence of ATA and SCSI counterparts.  However
> dragging in the associated baggage in order to emulate those interfaces
> unintentionally bloated usage of the config space to the point of breakage.
> To address this I'd moved from using config space to an unused BAR which
> (understandably) didn't go over too well.  Somewhere along the line Rusty
> posted a minimal alternative version which directly used a virtio request
> to retrieve the data from qemu which is arguably the right way to do the
> job.

*argh* That sounds like politics.

> That said we still had a dispute over what interface would be used to
> pass the S/N back to the guest: a new interface or reuse of an existing
> interface (eg: ATA IDENTIFY).  That's where things fizzled when we
> couldn't immediately resolve the issue.  So publishing the S/N in
> /sys would seem to side step this snag.

Re-using an existing interface would probable make it easier for
non-Linux OSses to also take advantage of this, since their ATA driver
is already there.

> I could have swore I sent out a guest-driver-app-interface-less
> version of the patch using virtio to pass the S/N but didn't find it in
> the archives.  I did however locate it and can bring it forward as a
> reference for the above if interest exists.

If it brings the issue forward and gives me hope to be able to do what
I want to do in a reasonable time frame, why not.

Does qemu have an issue tracker where a wishlist issue could be filed
to have this tracked?

Greetings
Marc

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