Re: [PATCH v5 5/8] blockdev: Add a new IF type IF_OTHER

[Daniel P . Berrangé]

On Thu, Jul 28, 2022 at 10:46:35AM +0100, Peter Maydell wrote:
> On Wed, 27 Jul 2022 at 20:03, Kevin Wolf <kwolf@redhat.com> wrote:
> >
> > Am 18.07.2022 um 11:49 hat Markus Armbruster geschrieben:
> > > An OTP device isn't really a parallel flash, and neither are eFuses.
> > > More fast-and-lose use of IF_PFLASH may exist in the tree, and maybe of
> > > other interface types, too.
> > >
> > > This patch introduces IF_OTHER.  The patch after next uses it for an
> > > EEPROM device.
> > >
> > > Do we want IF_OTHER?
> >
> > What would the semantics even be? Any block device that doesn't pick up
> > a different category may pick up IF_OTHER backends?
> >
> > It certainly feels like a strange interface to ask for "other" disk and
> > then getting as surprise what this other thing might be. It's
> > essentially the same as having an explicit '-device other', and I
> > suppose most people would find that strange.
> >
> > > If no, I guess we get to abuse IF_PFLASH some more.
> > >
> > > If yes, I guess we should use IF_PFLASH only for actual parallel flash
> > > memory going forward.  Cleaning up existing abuse of IF_PFLASH may not
> > > be worth the trouble, though.
> > >
> > > Thoughts?
> >
> > If the existing types aren't good enough (I don't have an opinion on
> > whether IF_PFLASH is a good match), let's add a new one. But a specific
> > new one, not just "other".
> 
> I think the common thread is "this isn't what anybody actually thinks
> of as being a 'disk', but we would like to back it with a block device
> anyway". That can cover a fair range of possibilities...

Given that, do we even want/have to use -drive for this ?    We can use
-blockdev for the backend and reference that from any -device we want
to create, and leave -drive out of the picture entirely

With regards,
Daniel
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