Re: [Xen-devel] [PATCH v14 3/3] iommu: add rmrr Xen command line option for extra rmrrs

[Venu Busireddy <venu.busireddy@xxxxxxxxxx>]

On Tue, Jan 24, 2017 at 08:52:50AM -0700, Jan Beulich wrote:
> >>> On 24.01.17 at 16:35, <venu.busireddy@xxxxxxxxxx> wrote:
> > On Tue, Jan 24, 2017 at 01:46:44AM -0700, Jan Beulich wrote:
> >> >>> On 23.01.17 at 19:20, <venu.busireddy@xxxxxxxxxx> wrote:
> >> > +        overlap = false;
> >> > +        list_for_each_entry(rmrru, &acpi_rmrr_units, list)
> >> > +        {
> >> > +            if ( pfn_to_paddr(base) <= rmrru->end_address &&
> >> > +                 rmrru->base_address <= pfn_to_paddr(end) )
> >> 
> >> So this now looks correct as long as rmrru->base_address is
> >> page aligned (as required by the spec), which should be good
> >> enough for now (considering that we make this assumption
> >> elsewhere). Nevertheless it would have been nice if you had,
> >> following the subsequent discussion with Elena, accounted for
> >> spec violations here.
> >> 
> >> > +        rmrr->segment = seg;
> >> > +        rmrr->base_address = pfn_to_paddr(user_rmrrs[i].base_pfn);
> >> > +        /* Align the end_address to the end of the page */
> >> > +        rmrr->end_address = pfn_to_paddr(user_rmrrs[i].end_pfn) | 
> > ~PAGE_MASK_4K;
> >> 
> >> Hmm, Ive just checked - in my reply to Elena I had intentionally used
> >> PAGE_MASK here (and I recall correcting it from PAGE_MASK_4K).
> >> What has led you to use PAGE_MASK_4K here, when pfn_to_paddr()
> >> uses PAGE_SHIFT?
> > 
> > Elena suggested to use PAGE_MASK_4K because the functions in
> > drivers/passthrough/vtd/iommu.c (including rmrr_identity_mapping())
> > use the _4K. With the current assumptions, both will work.
> 
> Granted this is somewhat of a mess, but I'd prefer if at least within
> a single statement things would be consistent in which page size is
> being meant.
> 
> > If you would like me to change this to PAGE_MASK, I will do so before
> > committing. Please let me know.
> 
> As said, I don't see a need for you to re-submit, unless there are
> other issues in need of taking care of.

Sure. I will change it to PAGE_MASK, but I will not resubmit the
patches. I will change it and commit it. Of course, assuming that there
are no other changes suggested by others.

Do I understand that I have your Ack?

> 
> Jan
> 

Venu


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