Messages in this thread | | | Date | Wed, 5 Jan 2022 09:49:45 +0800 | Subject | Re: [PATCH v11 01/17] perf/x86/intel: Add EPT-Friendly PEBS for Ice Lake Server | From | Like Xu <> |
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On 5/1/2022 1:25 am, Sean Christopherson wrote: > On Fri, Dec 31, 2021, Like Xu wrote: >> On 31/12/2021 2:13 am, Sean Christopherson wrote: >>> On Fri, Dec 10, 2021, Like Xu wrote: >>>> The new hardware facility supporting guest PEBS is only available on >>>> Intel Ice Lake Server platforms for now. KVM will check this field >>>> through perf_get_x86_pmu_capability() instead of hard coding the cpu >>>> models in the KVM code. If it is supported, the guest PEBS capability >>>> will be exposed to the guest. >>> >>> So what exactly is this new feature? I've speed read the cover letter and a few >>> changelogs and didn't find anything that actually explained when this feature does. >>> >> >> Please check Intel SDM Vol3 18.9.5 for this "EPT-Friendly PEBS" feature. >> >> I assume when an unfamiliar feature appears in the patch SUBJECT, >> the reviewer may search for the exact name in the specification. > > C'mon, seriously? How the blazes am I supposed to know that the feature name > is EPT-Friendly PEBS? Or that it's even in the SDM (it's not in the year-old > version of the SDM I currently have open) versus one of the many ISE docs?
You're right. The reviewer's time is valuable. Apologies for my wrong assumption.
> > This is not hard. Please spend the 30 seconds it takes to write a small blurb > so that reviewers don't have to spend 5+ minutes wondering WTF this does. > > Add support for EPT-Friendly PEBS, a new CPU feature that enlightens PEBS to > translate guest linear address through EPT, and facilitates handling VM-Exits > that occur when accessing PEBS records. More information can be found in the > <date> release of Intel's SDM, Volume 3, 18.9.5 "EPT-Friendly PEBS".
Applied and thanks.
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