Re: [PATCH v2] cxl: Check for invalid addresses returned from translation functions on errors

[Robert Richter]

On 06.01.26 10:42:36, Alison Schofield wrote:
> On Tue, Jan 06, 2026 at 06:23:58PM +0100, Robert Richter wrote:

> > @@ -3207,8 +3220,13 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
> >  		cxled = p->targets[i];
> >  		if (cxled->pos != pos)
> >  			continue;
> > +
> > +		dpa = cxl_dpa_resource_start(cxled);
> 
> We want to return -ENXIO, not 0 in this case.
> So jump out here immediately - right?
> 
> 		if (dpa == REsOURCE_SIZE_MAX)
> 			return -ENXIO;

The users of region_offset_to_dpa_result() handle the
RESOURCE_SIZE_MAX case. For that reason the dpa is not checked here.
I did not want to change the function interface with that fix.

Thanks for review.

-Robert

> 
> 
> > +		if (dpa != RESOURCE_SIZE_MAX)
> > +			dpa += dpa_offset;
> > +
> >  		result->cxlmd = cxled_to_memdev(cxled);
> > -		result->dpa = cxl_dpa_resource_start(cxled) + dpa_offset;
> > +		result->dpa = dpa;
> >  
> >  		return 0;
> >  	}