On Mon, Jun 24, 2019 at 10:43:21AM +0200, Paolo Bonzini wrote:
> On 24/06/19 10:06, Peter Xu wrote:
> > Well, if with such an error we'd better fix it right away in this
> > patch... :)
> >
> > Let me wait for some more comments, I'll touch that up too if I need a
> > repost.
>
> Looks good to me, except for one minor issue in this patch. But do not
> attribute this one to me, it's basically all code from you.
OK.
>
> > +static uint64_t vtd_get_next_mask(uint64_t start, uint64_t size, int gaw)
> > +{
> > + /* Tries to find smallest mask from start first */
> > + uint64_t rmask = start & -start, max_mask = 1ULL << gaw;
> > +
> > + assert(size && gaw > 0 && gaw < 64);
> > +
> > + /* Zero start, or too big */
> > + if (!rmask || rmask > max_mask) {
> > + rmask = max_mask;
> > + }
>
> Perhaps simpler:
>
> uint64_t max_mask = 1ULL << gaw;
> uint64_t alignment = start ? start & -start : max_mask;
>
(I'll add another "alignment = MIN(alignment, max_mask)" here if no
one disagree...)
> size = MIN(size, max_mask);
> if (alignment <= size) {
> /* Increase the alignment of start */
> return alignment;
> } else {
> /* Find the largest page mask from size */
> return 1ULL << (63 - clz64(size));
> }
>
> Also please rename it to get_naturally_aligned_size.
Will do. Thanks,
--
Peter Xu
