Re: [RFC 2/7] iommu/vt-d: Remove iova handling code from non-dma ops path

[Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>]

Hi,

On 5/5/19 9:19 AM, Lu Baolu wrote:
> Hi,
>
> On 5/4/19 9:23 PM, Tom Murphy via iommu wrote:
> > @@ -4181,58 +4168,37 @@ static int intel_iommu_memory_notifier(struct 
> > notifier_block *nb,
> >                          unsigned long val, void *v)
> >   {
> >       struct memory_notify *mhp = v;
> > -    unsigned long long start, end;
> > -    unsigned long start_vpfn, last_vpfn;
> > +    unsigned long start_vpfn = mm_to_dma_pfn(mhp->start_pfn);
> > +    unsigned long last_vpfn = mm_to_dma_pfn(mhp->start_pfn +
> > +            mhp->nr_pages - 1);
> >       switch (val) {
> >       case MEM_GOING_ONLINE:
> > -        start = mhp->start_pfn << PAGE_SHIFT;
> > -        end = ((mhp->start_pfn + mhp->nr_pages) << PAGE_SHIFT) - 1;
> > -        if (iommu_domain_identity_map(si_domain, start, end)) {
> > -            pr_warn("Failed to build identity map for [%llx-%llx]\n",
> > -                start, end);
> > +        if (iommu_domain_identity_map(si_domain, start_vpfn,
> > +                    last_vpfn)) {
> > +            pr_warn("Failed to build identity map for [%lx-%lx]\n",
> > +                start_vpfn, last_vpfn);
> >               return NOTIFY_BAD;
> >           }
> >           break;
>
> Actually we don't need to update the si_domain if iommu hardware
> supports pass-through mode. This should be made in a separated patch
> anyway.

Oh! please ignore it.

This callback is only registered when hardware doesn't support pass
through mode.

        if (si_domain && !hw_pass_through)
                register_memory_notifier(&intel_iommu_memory_nb);

Best regards,
Lu Baolu