Re: [PATCH v2] vfio-ccw: Permit missing IRQs

[Cornelia Huck]

On Fri, 23 Apr 2021 12:24:57 -0400
Eric Farman <farman@linux.ibm.com> wrote:

> On Fri, 2021-04-23 at 09:22 -0400, Matthew Rosato wrote:

> > So, this looks OK to me.  
> 
> +1 (Thanks for doing the research, Matt)

+1 to both the analysis and the thanks :)

> 
> > 
> >   
> > > handle any ioctl failure gracefully), but worth a second look. In
> > > fact,
> > > we already unregister the crw irq unconditionally, so we would
> > > likely
> > > already have seen any problems for that one, so I assume all is
> > > good.
> > >   
> > 
> > But +1 on driving the path and making sure it works anyway (do a 
> > double-unregister?)  
> 
> Yeah, works fine. Tried skipping the register of the CRW and double-
> unregistering the IO IRQ.
> 
> I also tried a combination where I unconditionally unregister the REQ
> IRQ, which obviously throws a message when it doesn't exist on the
> host.

Good, thanks for double-checking.

> 
> That might be nice to clean up so that adding new IRQs in the future is
> more intuitive; I'll add it to the list unless you want me to address
> it in a v2 of this. (Previously, the addition of the REQ IRQ needed to
> add the cleanup of the CRW IRQ. So the next IRQ would need to cleanup
> the REQ IRQ.)

Yeah, let's just do it on top.