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

[Joerg Roedel]

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