Re: [Intel-gfx] [PATCH v2 01/27] drm/i915/gvt: Verify pfn is "valid" before dereferencing "struct page"

[Andrzej Hajda <andrzej.hajda@xxxxxxxxx>]

On 13.03.2023 16:37, Wang, Wei W wrote:
> On Saturday, March 11, 2023 8:23 AM, Sean Christopherson wrote:
> > diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
> > index 4ec85308379a..58b9b316ae46 100644
> > --- a/drivers/gpu/drm/i915/gvt/gtt.c
> > +++ b/drivers/gpu/drm/i915/gvt/gtt.c
> > @@ -1183,6 +1183,10 @@ static int is_2MB_gtt_possible(struct intel_vgpu
> > *vgpu,
> >   	pfn = gfn_to_pfn(vgpu->vfio_device.kvm, ops->get_pfn(entry));
> >   	if (is_error_noslot_pfn(pfn))
> >   		return -EINVAL;
> > +
> > +	if (!pfn_valid(pfn))
> > +		return -EINVAL;
> > +
>
> Merge the two errors in one "if" to have less LOC?
> i.e.
> if (is_error_noslot_pfn(pfn) || !pfn_valid(pfn))
>      return -EINVAL;

you can just replace "if (is_error_noslot_pfn(pfn))" with "if 
(!pfn_valid(pfn))", it covers both cases.

Regards
Andrzej