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Date:   Thu, 22 Sep 2022 15:34:51 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     "Wang, Wei W" <wei.w.wang@intel.com>
Cc:     "Liang, Kan" <kan.liang@linux.intel.com>,
        "Li, Xiaoyao" <xiaoyao.li@intel.com>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        "Christopherson,, Sean" <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
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        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [RFC PATCH v2 2/3] perf/x86/intel/pt: Introduce and export
 pt_get_curr_event()
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References: <20220921164521.2858932-1-xiaoyao.li@intel.com>
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 <175b518c-d202-644e-a3a7-67e877852548@linux.intel.com>
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On Thu, Sep 22, 2022 at 12:58:49PM +0000, Wang, Wei W wrote:

> Add a function to expose the current running PT event to users. One usage is in KVM,
> it needs to get and disable the running host PT event before VMEnter to the guest and
> resumes the event after VMexit to host.

You cannot just kill a host event like that. If there is a host event,
the guest looses out.