Re: [Xen-devel] [PATCH v2 03/11] IOMMU/MMU: enhance the call trees of IOMMU unmapping and mapping

["Xu, Quan" <quan.xu@xxxxxxxxx>]

On April 20, 2016 2:12pm, <jbeulich@xxxxxxxx > wrote:
> >>> "Xu, Quan" <quan.xu@xxxxxxxxx> 04/20/16 7:29 AM >>>
> Ideally not, if it's a batch that it failing, The question just is whether at 
> the point
> you issue the error message you can know another got already emitted. In no
> case must this lead to spamming of the console originating from an 
> unprivileged
> domain.
> 
> >> > +                    if ( unlikely(ret) )
> >> > +                    {
> >> > +                        while (i)
> >> > +                            iommu_unmap_page(d, gfn + --i);
> >>
> >> How about below?
> >>
> >> while (i-- >= 0)
> >>    iommu_unmap_page(d, gfn + i);
> >
> >this modification is based on discussion rooted at
> >http://lists.xenproject.org/archives/html/xen-devel/2016-03/msg01779.ht
> >ml
> >wait for Jan's decision.
> 
> But did you really _follow_ that discussion? The adjustment done by that patch
> was specifically not deemed good, so the shape Kevin suggests is in line with 
> the
> outcome of that discussion (except that I'd suggest omitting the ">= 0", the
> more that i at least ought to be unsigned here).
> 

Based on your suggestions, I will fix it as below:

+while ( i-- )
+    iommu_unmap_page(d, gfn + i);

Quan



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