Re: [PATCH v2 2/2] s390x/pci: Fix memory_region_access_valid call

[Pierre Morel]

On 12/18/20 6:05 PM, Pierre Morel wrote:
> On 12/18/20 5:51 PM, Cornelia Huck wrote:
> > On Fri, 18 Dec 2020 17:40:50 +0100
> > Pierre Morel <pmorel@linux.ibm.com> wrote:
> >
> > > On 12/18/20 4:32 PM, Cornelia Huck wrote:
> > > > On Fri, 18 Dec 2020 15:32:08 +0100
> > > > Pierre Morel <pmorel@linux.ibm.com> wrote:
> > > > > On 12/18/20 12:04 PM, Cornelia Huck wrote:
> > > > > > On Fri, 18 Dec 2020 10:37:38 +0100
> > > > > > Pierre Morel <pmorel@linux.ibm.com> wrote:
> > > > > > > On 12/17/20 11:16 PM, Matthew Rosato wrote:
> > > > > > > > In pcistb_service_handler, a call is made to validate that the 
> > > > > > > > memory
> > > > > > > > region can be accessed.  However, the call is made using the 
> > > > > > > > entire length
> > > > > > > > of the pcistb operation, which can be larger than the allowed 
> > > > > > > > memory
> > > > > > > > access size (8).  Since we already know that the provided buffer 
> > > > > > > > is a
> > > > > > > > multiple of 8, fix the call to memory_region_access_valid to 
> > > > > > > > iterate
> > > > > > > > over the memory region in the same way as the subsequent call to
> > > > > > > > memory_region_dispatch_write.
> > > > > > > >
> > > > > > > > Fixes: 863f6f52b7 ("s390: implement pci instructions")
> > > > > > > > Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
> > > > > > > > ---

...snip...

> > > >
> > >
> > > The ops already exist, I thought adding a dedicated callback for s390 on
> > > every regions used by vfio_pci instead of the default.
> > > But it does not add a lot, just looks cleaner to me.
> >
> > But we end up here for every pci device, not just for vfio devices,
> > don't we?
>
> Yes, but isn't what is done here?

It was not my intention to slow the integration process.
We can start with this fix and eventually move the code to the callback 
in another series when/if we all agree.

Acked-by: Pierre Morel <pmorel@linux.ibm.com>



--
Pierre Morel
IBM Lab Boeblingen