> -----Original Message-----
> From: Jan Beulich [mailto:[email protected]]
> Sent: 04 December 2018 14:25
> To: Paul Durrant <[email protected]>
> Cc: Brian Woods <[email protected]>; Suravee Suthikulpanit
> <[email protected]>; Andrew Cooper
> <[email protected]>; Roger Pau Monne <[email protected]>; Wei
> Liu <[email protected]>; xen-devel <[email protected]>
> Subject: Re: [PATCH v2 1/4] amd-iommu: add flush iommu_ops
>
> >>> On 03.12.18 at 18:40, <[email protected]> wrote:
> > +static unsigned long flush_count(unsigned long dfn, unsigned int
> page_count,
> > + unsigned int order)
> > +{
> > + unsigned long start = dfn / (1u << order);
> > + unsigned long end = DIV_ROUND_UP(dfn + page_count, (1u << order));
>
> Luckily this in not in generic code, so the anomaly at the upper address
> space end is not going to surface, and in particular not cause ...
>
> > + ASSERT(end > start);
>
> ... this to trigger. I therefore nevertheless wonder whether it
> would't be better to use
>
> unsigned long start = dfn >> order;
> unsigned long end = (dfn + page_count - 1) >> order) + 1;
>
> instead.
Yes, that's much better... don't know why I didn't do it that way in the first
place.
>
> > --- a/xen/include/xen/iommu.h
> > +++ b/xen/include/xen/iommu.h
> > @@ -52,6 +52,11 @@ static inline bool_t dfn_eq(dfn_t x, dfn_t y)
> > return dfn_x(x) == dfn_x(y);
> > }
> >
> > +static inline bool_t dfn_lt(dfn_t x, dfn_t y)
> > +{
> > + return dfn_x(x) < dfn_x(y);
> > +}
>
> The revision log says this is gone ...
>
Oh. I must have messed up my git commands and accidentally put it back during
rebase.
> With it really gone, and irrespective of the other comment
> Reviewed-by: Jan Beulich <[email protected]>
>
Thanks.
> Of course one or both adjustments could be easily done while
> committing, provided you agree and provided there's no other
> need for a v3.
Ok, you're comments on patch #2 suggest there will probably by a v3 so I can
fix.
Paul
>
> Jan
>
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