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Message-ID: <4373e8d7-e3e8-164c-75e3-6ca495a79167@amd.com>
Date:   Mon, 14 Feb 2022 15:44:34 +0530
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Subject: Re: [PATCH v2 2/6] KVM: x86/pmu: Refactoring find_arch_event() to
 pmc_perf_hw_id()
Content-Language: en-US
To:     Jim Mattson <jmattson@google.com>
Cc:     Like Xu <like.xu.linux@gmail.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Joerg Roedel <joro@8bytes.org>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, David Dunn <daviddunn@google.com>,
        Stephane Eranian <eranian@google.com>,
        Kim Phillips <kim.phillips@amd.com>,
        Ravi Bangoria <ravi.bangoria@amd.com>
References: <20211130074221.93635-1-likexu@tencent.com>
 <20211130074221.93635-3-likexu@tencent.com>
 <CALMp9eQG7eqq+u3igApsRDV=tt0LdjZzmD_dC8zw=gt=f5NjSA@mail.gmail.com>
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 <CALMp9eTVxN34fCV8q53_38R2DxNdR9_1aSoRmF8gKt2yhOMndg@mail.gmail.com>
 <3bedc79a-5e60-677c-465b-3bc8aa2daad8@gmail.com>
 <d4dae262-3063-3225-c6e1-3a8513a497ec@amd.com>
 <CALMp9eShc-o+OZ3j4kDkTbXmY58wQu6Rq6qviZAHsDr4X21a5Q@mail.gmail.com>
From:   Ravi Bangoria <ravi.bangoria@amd.com>
In-Reply-To: <CALMp9eShc-o+OZ3j4kDkTbXmY58wQu6Rq6qviZAHsDr4X21a5Q@mail.gmail.com>
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On 11-Feb-22 11:46 PM, Jim Mattson wrote:
> On Fri, Feb 11, 2022 at 1:56 AM Ravi Bangoria <ravi.bangoria@amd.com> wrote:
>>
>>
>>
>> On 10-Feb-22 4:58 PM, Like Xu wrote:
>>> cc Kim and Ravi to help confirm more details about this change.
>>>
>>> On 10/2/2022 3:30 am, Jim Mattson wrote:
>>>> By the way, the following events from amd_event_mapping[] are not
>>>> listed in the Milan PPR:
>>>> { 0x7d, 0x07, PERF_COUNT_HW_CACHE_REFERENCES }
>>>> { 0x7e, 0x07, PERF_COUNT_HW_CACHE_MISSES }
>>>> { 0xd0, 0x00, PERF_COUNT_HW_STALLED_CYCLES_FRONTEND }
>>>> { 0xd1, 0x00, PERF_COUNT_HW_STALLED_CYCLES_BACKEND }
>>>>
>>>> Perhaps we should build a table based on amd_f17h_perfmon_event_map[]
>>>> for newer AMD processors?
>>
>> I think Like's other patch series to unify event mapping across kvm
>> and host will fix it. No?
>> https://lore.kernel.org/lkml/20220117085307.93030-4-likexu@tencent.com
> 
> Yes, that should fix it. But why do we even bother? What is the
> downside of using PERF_TYPE_RAW all of the time?

There are few places where PERF_TYPE_HARDWARE and PERF_TYPE_RAW are treated
differently. Ex, x86_pmu_event_init(), perf_init_event(). So I think it makes
sense to keep using PERF_TYPE_HARDWARE for generalized events?

Ravi