[Qemu-devel] Re: [PATCH 0/2] fix virtio_blk serial pci config breakage

[Anthony Liguori]

john cooper wrote:
> Anthony Liguori wrote:
>
> > 2) Passing an ATA identity page is goofy.  We should just pass the 
> > serial number and let Linux generate the identity page.
>
> I have a hard time disagreeing with that comment.
>
> But the rationale that got us here was from the
> user's perspective this information could be
> trivially exposed via a preexisting interface vs.
> creating a new interface as I'd done initially.
> It was also pointed out other defined fields in
> the identify page exist which were potentially
> useful.  So pressing a HDIO_GET_IDENTITY ioctl
> into service here didn't seem unreasonable.

virtio-blk isn't an ATA device so why pretend like it is?

We can present the information we think is useful to the guest in a 
concise format and then if the guest wants to pretend it's an ATA 
device, it can create the ATA identify page on the fly.

> > Just because Linux requires this as it's user space interface, that 
> > doesn't mean that other guests will (like Windows).  Instead of 
> > exposing an opaque blob, we should expose the information we need in 
> > a structured way.
>
> The identify page is defined as the return of an
> "identify drive" command from an ATA drive/controller.
> I'd hazard it is a familiar structure in a windows
> driver/userland context as well.

Regards,

Anthony Liguori