From: "Wang, Wei W" <wei.w.wang@intel.com>
To: "Liang, Kan" <kan.liang@linux.intel.com>,
"Li, Xiaoyao" <xiaoyao.li@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
"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>,
"Liang, Kan" <kan.liang@intel.com>,
"Kleen, Andi" <andi.kleen@intel.com>
Cc: "linux-perf-users@vger.kernel.org"
<linux-perf-users@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: RE: [RFC PATCH 0/2] KVM: VMX: Fix VM entry failure on PT_MODE_HOST_GUEST while host is using PT
Date: Mon, 19 Sep 2022 15:22:58 +0000 [thread overview]
Message-ID: <DS0PR11MB6373ACD91938CE70EBADA831DC4D9@DS0PR11MB6373.namprd11.prod.outlook.com> (raw)
In-Reply-To: <b3d3fd4c-b191-c4e4-ac95-c46f944c65d6@linux.intel.com>
On Monday, September 19, 2022 10:41 PM, Liang, Kan wrote:
> Another fake event? We have to specially handle it in the perf code. I don't
> think it's a clean way for perf.
We can check the patch later. I think it should be clean, like the LBR side.
>
> > - on VMEnter:
> > -- perf_disable_event_local(host_event);
> > -- perf_enable_event_local(guest_event);
> > - on VMExit:
> > -- perf_disable_event_local(guest_event);
> > -- perf_enable_event_local(host_event);
>
> Why we cannot use the same way as the perf core driver to switch the MSRs in
> the VMCS?
The current MSR switching list from VMCS isn’t fast,
should be the last resort when really necessary.
>
> You just need one generic function, perf_guest_get_msrs(), for both PT and
> core driver. If you have to disable PT explicitly before VMCS, I think you can do
> it in the PT specific perf_guest_get_msrs().
The disable is done via " Clear IA32_RTIT_CTL" VMExit control.
It can ensure PT disabled in time on VMExit, so no need to go through perf_guest_get_msrs.
Thanks,
Wei
next prev parent reply other threads:[~2022-09-19 15:24 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-25 8:56 [RFC PATCH 0/2] KVM: VMX: Fix VM entry failure on PT_MODE_HOST_GUEST while host is using PT Xiaoyao Li
2022-08-25 8:56 ` [RFC PATCH 1/2] perf/x86/intel/pt: Introduce intel_pt_{stop,resume}() Xiaoyao Li
2022-08-25 15:23 ` Sean Christopherson
2022-08-25 8:56 ` [RFC PATCH 2/2] KVM: VMX: Stop/resume host PT before/after VM entry when PT_MODE_HOST_GUEST Xiaoyao Li
2022-08-25 15:34 ` Sean Christopherson
2022-08-25 15:45 ` Xiaoyao Li
2022-08-25 15:59 ` Sean Christopherson
2022-08-26 6:32 ` Xiaoyao Li
2022-08-26 15:08 ` Sean Christopherson
2022-08-29 7:49 ` [RFC PATCH 0/2] KVM: VMX: Fix VM entry failure on PT_MODE_HOST_GUEST while host is using PT Wang, Wei W
2022-08-29 17:33 ` Sean Christopherson
2022-08-30 6:02 ` Wang, Wei W
2022-09-08 7:25 ` Xiaoyao Li
2022-09-08 8:53 ` Wang, Wei W
2022-09-14 4:15 ` Xiaoyao Li
2022-09-14 6:16 ` Wang, Wei W
2022-09-14 20:25 ` Liang, Kan
2022-09-15 2:46 ` Wang, Wei W
2022-09-15 13:54 ` Liang, Kan
2022-09-15 14:39 ` Wang, Wei W
2022-09-15 15:42 ` Liang, Kan
2022-09-16 2:30 ` Wang, Wei W
2022-09-16 13:27 ` Liang, Kan
2022-09-19 13:46 ` Wang, Wei W
2022-09-19 14:41 ` Liang, Kan
2022-09-19 15:22 ` Wang, Wei W [this message]
2022-09-19 15:55 ` Liang, Kan
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