Re: [PATCH V4 0/6] perf/amd/iommu: Enable multi-IOMMU support

[Suravee Suthikulpanit]

On 02/23/2016 06:27 PM, Suravee Suthikulpanit wrote:
> Hi,
>
> On 02/23/2016 06:04 PM, Joerg Roedel wrote:
> > Hi Suravee,
> >
> > On Thu, Feb 11, 2016 at 04:15:21PM +0700, Suthikulpanit, Suravee wrote:
> > > From: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
> > >
> > > This patch series modifies the existing perf_event_amd_iommu driver
> > > to support systems with multiple IOMMUs. It introduces new AMD IOMMU
> > > APIs,
> > > which are used by the AMD IOMMU Perf driver to access performance
> > > counters in multiple IOMMUs.
> > >
> > > In addition, this series should also fix current AMD IOMMU PMU driver
> > > initialization issue in some existing KV and CZ platform, where it fails
> > > to write to IOMMU perf counter as reported by Andreas Hartmann here
> > > (http://comments.gmane.org/gmane.linux.kernel.pci/49147).
> >
> > Since that problem also affects older kernels, we need a stand-alone
> > fix for this initialization issue. We can't backport new features to fix
> > bugs in old kernels.
> >
> >
> >     Joerg
>
> OK, I am spliting V5 into two part. First would be just to fix the
> issue. Then the second part would be to add the multiple IOMMU support.
>
> Suravee

Actually, my V5 is rebased from tips which has moved several files. I 
think we might need to create a separate patch series to fix this issue 
in older kernels. Which branch should I rebase my changes for the older 
kernel?

Suravee