[SRU][B/C/D] iommu/amd: Reserve and correctly set exclusion range in iova-domain

[Jeffrey Lane]

Hi,

I wanted to ask if there was anything I could do to help get this
acked so it makes the next SRU cycle?

Thanks
Jeff

On Mon, Jun 17, 2019 at 9:52 AM Jeffrey Lane <jeffrey.lane at canonical.com> wrote:
>
> Hi,
>
> Could I get a second ack on these (connork acked it earlier)?
> I was hoping this could make this cycle, if at all possible.
>
> Thanks
> Jeff
>
> On Fri, Jun 7, 2019 at 1:34 PM Jeff Lane <jeffrey.lane at canonical.com> wrote:
> >
> > BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1823037
> >
> > [Impact]
> > If a device has an exclusion range specified in the IVRS table, this region
> > needs to be reserved in the iova-domain of that device. This hasn't happened
> > until now and can cause data corruption on data transfered with these devices.
> >
> > The exlcusion range limit register needs to contain the base-address of the
> > last page that is part of the range, as bits 0-11 of this register are treated
> > as 0xfff by the hardware for comparisons.
> >
> > So correctly set the exclusion range in the hardware to the last page which is
> > _in_ the range.
> >
> > [Testing]
> > This was tested by Dell for 24+ hours with positive test results. Testing
> > involved creating multiple directories with a million files each and then
> > another script was used across 3-5 threads copying files from one location
> > to another.  Prior to using test kernels with these patches applied, the system
> > would fail within 1 - 2 hours consistently.
> >
> > [Regression Risk]
> > Low,this adds memory protection to the driver and has already been applied
> > upstream and patched test kernels for all three releases have been tested by
> > Dell for 24 hours with no failures noted.
> >
> > Patches cleanly apply to Bionic, Cosmic and Disco. Bionic and Cosmic require
> > both patches, but Disco only requires the second patch (Set exclusion rage
> > correctly) as the first patch was already picked up in a previous SRU
> > (LP: #1830934)
> >
> >
> >
>
>
> --
> Jeff Lane
> Technical Partnership and Server Certification Programmes
>
> "Entropy isn't what it used to be."



-- 
Jeff Lane
Technical Partnership and Server Certification Programmes

"Entropy isn't what it used to be."