Re: [Xen-devel] [PATCH v9 1/3] vt-d: fix the IOMMU flush issue

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

On June 21, 2016 9:25 PM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
> >>> On 17.06.16 at 05:37, <quan.xu@xxxxxxxxx> wrote:
> > @@ -546,17 +550,37 @@ static int __must_check iommu_flush_all(void)
> >      struct acpi_drhd_unit *drhd;
> >      struct iommu *iommu;
> >      int flush_dev_iotlb;
> > +    int rc = 0;
> >
> >      flush_all_cache();
> >      for_each_drhd_unit ( drhd )
> >      {
> > +        int context_rc, iotlb_rc;
> > +
> >          iommu = drhd->iommu;
> > -        iommu_flush_context_global(iommu, 0);
> > +        context_rc = iommu_flush_context_global(iommu, 0);
> >          flush_dev_iotlb = find_ats_dev_drhd(iommu) ? 1 : 0;
> > -        iommu_flush_iotlb_global(iommu, 0, flush_dev_iotlb);
> > +        iotlb_rc = iommu_flush_iotlb_global(iommu, 0,
> > + flush_dev_iotlb);
> > +
> > +        /*
> > +         * The current logic for returns:
> > +         *   - positive  invoke iommu_flush_write_buffer to flush cache.
> > +         *   - zero      on success.
> > +         *   - negative  on failure. Continue to flush IOMMU IOTLB on a
> > +         *               best effort basis.
> > +         */
> > +        if ( context_rc > 0 || iotlb_rc > 0 )
> > +            iommu_flush_write_buffer(iommu);
> > +        if ( context_rc >= 0 )
> 
> Wasn't this meant to be just "rc"? (I can't, btw, imagine Kevin's ack to be
> rightfully retained with a change like this.)
>
SORRY, it is 'rc'. It is really my mistake here, but Kevin's ack is right as 
the previous v8 was:

+        if ( rc >= 0 )
+            rc = iommu_rc;
+        if ( rc >= 0 )
+            rc = iommu_ret;

,, I will send it out again with this fix.

Quan

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