From: Wei Wang <wei.w.wang@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
pbonzini@redhat.com, ak@linux.intel.com, kan.liang@intel.com,
mingo@redhat.com, rkrcmar@redhat.com, like.xu@intel.com,
jannh@google.com, arei.gonglei@huawei.com, jmattson@google.com
Subject: Re: [PATCH v7 12/12] KVM/VMX/vPMU: support to report GLOBAL_STATUS_LBRS_FROZEN
Date: Tue, 09 Jul 2019 11:24:07 +0800 [thread overview]
Message-ID: <5D2408D7.3000002@intel.com> (raw)
In-Reply-To: <20190708150909.GP3402@hirez.programming.kicks-ass.net>
On 07/08/2019 11:09 PM, Peter Zijlstra wrote:
> On Mon, Jul 08, 2019 at 09:23:19AM +0800, Wei Wang wrote:
>> This patch enables the LBR related features in Arch v4 in advance,
>> though the current vPMU only has v2 support. Other arch v4 related
>> support will be enabled later in another series.
>>
>> Arch v4 supports streamlined Freeze_LBR_on_PMI. According to the SDM,
>> the LBR_FRZ bit is set to global status when debugctl.freeze_lbr_on_pmi
>> has been set and a PMI is generated. The CTR_FRZ bit is set when
>> debugctl.freeze_perfmon_on_pmi is set and a PMI is generated.
> (that's still a misnomer; it is: freeze_perfmon_on_overflow)
OK. (but that was directly copied from the sdm 18.2.4.1)
> Why?
>
> Who uses that v4 crud?
I saw the native perf driver has been updated to v4.
After the vPMU gets updated to v4, the guest perf would use that.
If you prefer to hold on this patch until vPMU v4 support,
we could do that as well.
> It's broken. It looses events between overflow
> and PMI.
Do you mean it's a v4 hardware issue?
Best,
Wei
next prev parent reply other threads:[~2019-07-09 3:18 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-08 1:23 [PATCH v7 00/12] Guest LBR Enabling Wei Wang
2019-07-08 1:23 ` [PATCH v7 01/12] perf/x86: fix the variable type of the LBR MSRs Wei Wang
2019-07-08 1:23 ` [PATCH v7 02/12] perf/x86: add a function to get the lbr stack Wei Wang
2019-07-08 1:23 ` [PATCH v7 03/12] KVM/x86: KVM_CAP_X86_GUEST_LBR Wei Wang
2019-07-08 1:23 ` [PATCH v7 04/12] KVM/x86: intel_pmu_lbr_enable Wei Wang
2019-07-08 1:23 ` [PATCH v7 05/12] KVM/x86/vPMU: tweak kvm_pmu_get_msr Wei Wang
2019-07-08 1:23 ` [PATCH v7 06/12] KVM/x86: expose MSR_IA32_PERF_CAPABILITIES to the guest Wei Wang
2019-07-08 1:23 ` [PATCH v7 07/12] perf/x86: no counter allocation support Wei Wang
2019-07-08 14:29 ` Peter Zijlstra
2019-07-09 2:58 ` Wei Wang
2019-07-09 9:43 ` Peter Zijlstra
2019-07-09 11:36 ` Wei Wang
2019-07-08 1:23 ` [PATCH v7 08/12] KVM/x86/vPMU: Add APIs to support host save/restore the guest lbr stack Wei Wang
2019-07-08 14:48 ` Peter Zijlstra
2019-07-09 3:04 ` Wei Wang
2019-07-09 9:39 ` Peter Zijlstra
2019-07-09 11:34 ` Wei Wang
2019-07-09 12:19 ` Peter Zijlstra
2019-07-10 8:19 ` Wei Wang
2019-07-09 11:45 ` Peter Zijlstra
2019-07-10 8:21 ` Wei Wang
2019-07-08 1:23 ` [PATCH v7 09/12] perf/x86: save/restore LBR_SELECT on vCPU switching Wei Wang
2019-07-08 1:23 ` [PATCH v7 10/12] KVM/x86/lbr: lazy save the guest lbr stack Wei Wang
2019-07-08 14:53 ` Peter Zijlstra
2019-07-08 15:11 ` Andi Kleen
2019-07-09 11:39 ` Peter Zijlstra
2019-07-09 3:14 ` Wei Wang
2019-07-08 1:23 ` [PATCH v7 11/12] KVM/x86: remove the common handling of the debugctl msr Wei Wang
2019-07-08 1:23 ` [PATCH v7 12/12] KVM/VMX/vPMU: support to report GLOBAL_STATUS_LBRS_FROZEN Wei Wang
2019-07-08 15:09 ` Peter Zijlstra
2019-07-09 3:24 ` Wei Wang [this message]
2019-07-09 11:35 ` Peter Zijlstra
2019-07-10 9:23 ` Wei Wang
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