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Subject: Re: [PATCH] iommu: amd: Fix IOMMU perf counter clobbering during init
To:     Joerg Roedel <joro@8bytes.org>,
        Shuah Khan <skhan@linuxfoundation.org>
Cc:     iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
References: <20200114151220.29578-1-skhan@linuxfoundation.org>
 <20200117100829.GE15760@8bytes.org>
From:   Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Message-ID: <42c0a806-9947-1401-9754-8aa88bd7062f@amd.com>
Date:   Tue, 21 Jan 2020 09:10:41 +0700
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On 1/17/2020 5:08 PM, Joerg Roedel wrote:
> Adding Suravee, who wrote the IOMMU Perf Counter code.
> 
> On Tue, Jan 14, 2020 at 08:12:20AM -0700, Shuah Khan wrote:
>> init_iommu_perf_ctr() clobbers the register when it checks write access
>> to IOMMU perf counters and fails to restore when they are writable.
>>
>> Add save and restore to fix it.
>>
>> Signed-off-by: Shuah Khan<skhan@linuxfoundation.org>
>> ---
>>   drivers/iommu/amd_iommu_init.c | 22 ++++++++++++++++------
>>   1 file changed, 16 insertions(+), 6 deletions(-)
> Suravee, can you please review this patch?
> 

This looks ok. Does this fix certain issues? Or is this just for sanity.

Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>

Thanks,
Suravee