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Subject: Re: [PATCH v4 01/16] perf/x86/intel: Add x86_pmu.pebs_vmx for Ice
 Lake Servers
To:     Andi Kleen <andi@firstfloor.org>
References: <20210329054137.120994-2-like.xu@linux.intel.com>
 <606BD46F.7050903@huawei.com>
 <20210406124746.ji5iqladdlh73mok@two.firstfloor.org>
CC:     <like.xu@linux.intel.com>,
        "Fangyi (Eric)" <eric.fangyi@huawei.com>,
        Xiexiangyou <xiexiangyou@huawei.com>,
        <kan.liang@linux.intel.com>, <kvm@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <wei.w.wang@intel.com>,
        <x86@kernel.org>
From:   "Liuxiangdong (Aven, Cloud Infrastructure Service Product Dept.)" 
        <liuxiangdong5@huawei.com>
Message-ID: <606D2170.6020203@huawei.com>
Date:   Wed, 7 Apr 2021 11:05:20 +0800
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On 2021/4/6 20:47, Andi Kleen wrote:
>> AFAIK， Icelake supports adaptive PEBS and extended PEBS which Skylake
>> doesn't.
>> But we can still use IA32_PEBS_ENABLE MSR to indicate general-purpose
>> counter in Skylake.
>> Is there anything else that only Icelake supports in this patches set?
> Only Icelake server has the support for recovering from a EPT violation
> on the PEBS data structures. To use it on Skylake server you would
> need to pin the whole guest, but that is currently not done.
Sorry. Some questions about "Pin the whole guest". Do you mean VmPin 
equals VmSize
in "/proc/$(pidof qemu-kvm)/status"? Or just VmLck equals VmSize? Or 
something else?
>> Besides, we have tried this patches set in Icelake.  We can use pebs(eg:
>> "perf record -e cycles:pp")
>> when guest is kernel-5.11, but can't when kernel-4.18.  Is there a minimum
>> guest kernel version requirement?
> You would need a guest kernel that supports Icelake server PEBS. 4.18
> would need backports for tht.
>
>
> -Andi