From: Peter Zijlstra <peterz@infradead.org>
To: Like Xu <like.xu.linux@gmail.com>
Cc: Jim Mattson <jmattson@google.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,
Stephane Eranian <eranian@google.com>,
David Dunn <daviddunn@google.com>
Subject: Re: KVM: x86: Reconsider the current approach of vPMU
Date: Wed, 9 Feb 2022 14:33:15 +0100 [thread overview]
Message-ID: <YgPCm1WIt9dHuoEo@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <2db2ebbe-e552-b974-fc77-870d958465ba@gmail.com>
On Wed, Feb 09, 2022 at 04:10:48PM +0800, Like Xu wrote:
> On 3/2/2022 6:35 am, Jim Mattson wrote:
> > 3) TDX is going to pull the rug out from under us anyway. When the TDX
> > module usurps control of the PMU, any active host counters are going
> > to stop counting. We are going to need a way of telling the host perf
>
> I presume that performance counters data of TDX guest is isolated for host,
> and host counters (from host perf agent) will not stop and keep counting
> only for TDX guests in debug mode.
Right, lots of people like profiling guests from the host. That allows
including all the other virt gunk that supports the guest.
Guests must not unilaterally steal the PMU.
> At one time, we proposed to statically reserve counters from the host
> perf view at guest startup, but this option was NAK-ed from PeterZ.
Because counter constraints, if you hand C0 to the guest, the host
can no longer count certain events, which is bad.
next prev parent reply other threads:[~2022-02-09 13:33 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-17 8:53 [PATCH kvm/queue v2 0/3] KVM: x86/pmu: Fix out-of-date AMD amd_event_mapping[] Like Xu
2022-01-17 8:53 ` [PATCH kvm/queue v2 1/3] KVM: x86/pmu: Replace pmu->available_event_types with a new BITMAP Like Xu
2022-02-01 12:26 ` Paolo Bonzini
2022-01-17 8:53 ` [PATCH kvm/queue v2 2/3] perf: x86/core: Add interface to query perfmon_event_map[] directly Like Xu
2022-02-01 12:27 ` Paolo Bonzini
2022-02-02 14:43 ` Peter Zijlstra
2022-02-02 22:35 ` Jim Mattson
2022-02-03 17:33 ` David Dunn
2022-02-09 8:10 ` KVM: x86: Reconsider the current approach of vPMU Like Xu
2022-02-09 13:33 ` Peter Zijlstra [this message]
2022-02-09 21:00 ` Sean Christopherson
2022-02-10 12:08 ` Like Xu
2022-02-10 17:12 ` Sean Christopherson
2022-02-16 3:33 ` Like Xu
2022-02-16 17:53 ` Jim Mattson
2022-02-09 13:21 ` [PATCH kvm/queue v2 2/3] perf: x86/core: Add interface to query perfmon_event_map[] directly Peter Zijlstra
2022-02-09 15:40 ` Dave Hansen
2022-02-09 18:47 ` Jim Mattson
2022-02-09 18:57 ` Dave Hansen
2022-02-09 19:24 ` David Dunn
2022-02-10 13:29 ` Like Xu
2022-02-10 15:34 ` Liang, Kan
2022-02-10 16:34 ` Jim Mattson
2022-02-10 18:30 ` Liang, Kan
2022-02-10 19:16 ` Jim Mattson
2022-02-10 19:46 ` Liang, Kan
2022-02-10 19:55 ` David Dunn
2022-02-11 14:11 ` Liang, Kan
2022-02-11 18:08 ` Jim Mattson
2022-02-11 21:47 ` Liang, Kan
2022-02-12 23:31 ` Jim Mattson
2022-02-14 21:55 ` Liang, Kan
2022-02-14 22:55 ` Jim Mattson
2022-02-16 7:36 ` Like Xu
2022-02-16 18:10 ` Jim Mattson
2022-02-16 7:30 ` Like Xu
2022-02-16 5:08 ` Like Xu
2022-02-10 12:55 ` Like Xu
2022-02-12 23:32 ` Jim Mattson
2022-02-08 11:52 ` Like Xu
2022-01-17 8:53 ` [PATCH kvm/queue v2 3/3] KVM: x86/pmu: Setup the {inte|amd}_event_mapping[] when hardware_setup Like Xu
2022-02-01 12:28 ` Paolo Bonzini
2022-02-08 10:10 ` Like Xu
2022-01-26 11:22 ` [PATCH kvm/queue v2 0/3] KVM: x86/pmu: Fix out-of-date AMD amd_event_mapping[] Like Xu
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