linux-kernel - Re: [PATCH v8 9/9] perf/amd/iommu: Enable support for multiple IOMMUs

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Date:   Wed, 25 Jan 2017 10:55:38 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        linux-kernel@...r.kernel.org, iommu@...ts.linux-foundation.org,
        joro@...tes.org, mingo@...hat.com
Subject: Re: [PATCH v8 9/9] perf/amd/iommu: Enable support for multiple IOMMUs

On Wed, Jan 25, 2017 at 10:46:53AM +0100, Peter Zijlstra wrote:
> Which is absolutely insane.

Right,

IMO, the simplest thing to do for your purposes is to embed a struct
amd_iommu pointer into struct perf_amd_iommu at init time so that you
don't have to do all that crazy dance in the PMU functions and iterate
over the iommus in get_amd_iommu() each time.

Which would then simplify all your other functions. For example:

int amd_iommu_pc_get_reg(unsigned int idx, u8 bank, u8 cntr, u8 fxn, u64 *value)

should be

int amd_iommu_pc_get_reg(struct amd_iommu *iommu, u8 bank, u8 cntr, u8 fxn, u64 *value)

and you can save yourself a lot of glue code and get rid of that
get_amd_iommu() thing.

-- 
Regards/Gruss,
    Boris.

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