From: "Chen, Zide" <zide.chen@intel.com>
To: "Mi, Dapeng" <dapeng1.mi@linux.intel.com>,
Mingwei Zhang <mizhang@google.com>,
Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Xiong Zhang <xiong.y.zhang@intel.com>,
Kan Liang <kan.liang@intel.com>,
Zhenyu Wang <zhenyuw@linux.intel.com>,
Manali Shukla <manali.shukla@amd.com>,
Sandipan Das <sandipan.das@amd.com>
Cc: Jim Mattson <jmattson@google.com>,
Stephane Eranian <eranian@google.com>,
Ian Rogers <irogers@google.com>,
Namhyung Kim <namhyung@kernel.org>,
gce-passthrou-pmu-dev@google.com,
Samantha Alt <samantha.alt@intel.com>,
Zhiyuan Lv <zhiyuan.lv@intel.com>,
Yanfei Xu <yanfei.xu@intel.com>, maobibo <maobibo@loongson.cn>,
Like Xu <like.xu.linux@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
kvm@vger.kernel.org, linux-perf-users@vger.kernel.org
Subject: Re: [PATCH v2 26/54] KVM: x86/pmu: Avoid legacy vPMU code when accessing global_ctrl in passthrough vPMU
Date: Wed, 8 May 2024 18:29:36 -0700 [thread overview]
Message-ID: <e7bc3989-154b-42cb-9a6b-83b395f5d0ee@intel.com> (raw)
In-Reply-To: <9b93c6bb-0182-4729-a935-2c05f1160a73@linux.intel.com>
On 5/8/2024 5:43 PM, Mi, Dapeng wrote:
>
> On 5/9/2024 5:48 AM, Chen, Zide wrote:
>>
>> On 5/5/2024 10:29 PM, Mingwei Zhang wrote:
>>> Avoid calling into legacy/emulated vPMU logic such as reprogram_counters()
>>> when passthrough vPMU is enabled. Note that even when passthrough vPMU is
>>> enabled, global_ctrl may still be intercepted if guest VM only sees a
>>> subset of the counters.
>>>
>>> Suggested-by: Xiong Zhang <xiong.y.zhang@linux.intel.com>
>>> Signed-off-by: Mingwei Zhang <mizhang@google.com>
>>> ---
>>> arch/x86/kvm/pmu.c | 3 ++-
>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
>>> index bd94f2d67f5c..e9047051489e 100644
>>> --- a/arch/x86/kvm/pmu.c
>>> +++ b/arch/x86/kvm/pmu.c
>>> @@ -713,7 +713,8 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>>> if (pmu->global_ctrl != data) {
>>> diff = pmu->global_ctrl ^ data;
>>> pmu->global_ctrl = data;
>>> - reprogram_counters(pmu, diff);
>>> + if (!is_passthrough_pmu_enabled(vcpu))
>>> + reprogram_counters(pmu, diff);
>> Since in [PATCH 44/54], reprogram_counters() is effectively skipped in
>> the passthrough case, is this patch still needed?
> Zide, reprogram_counters() and reprogram_counter() are two different
> helpers. Both they need to be skipped in passthrough mode.
Yes, but this is talking about reprogram_counters() only. passthrough
mode is being checked inside and outside the function call, which is
redundant.
next prev parent reply other threads:[~2024-05-09 1:29 UTC|newest]
Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-06 5:29 [PATCH v2 00/54] Mediated Passthrough vPMU 2.0 for x86 Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 01/54] KVM: x86/pmu: Set enable bits for GP counters in PERF_GLOBAL_CTRL at "RESET" Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 02/54] KVM: x86: Snapshot if a vCPU's vendor model is AMD vs. Intel compatible Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 03/54] KVM: x86/pmu: Do not mask LVTPC when handling a PMI on AMD platforms Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 04/54] x86/msr: Define PerfCntrGlobalStatusSet register Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 05/54] x86/msr: Introduce MSR_CORE_PERF_GLOBAL_STATUS_SET Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 06/54] perf: Support get/put passthrough PMU interfaces Mingwei Zhang
2024-05-07 8:31 ` Peter Zijlstra
2024-05-08 4:13 ` Zhang, Xiong Y
2024-05-07 8:41 ` Peter Zijlstra
2024-05-08 4:54 ` Zhang, Xiong Y
2024-05-08 8:32 ` Peter Zijlstra
2024-05-06 5:29 ` [PATCH v2 07/54] perf: Add generic exclude_guest support Mingwei Zhang
2024-05-07 8:58 ` Peter Zijlstra
2024-05-06 5:29 ` [PATCH v2 08/54] perf/x86/intel: Support PERF_PMU_CAP_PASSTHROUGH_VPMU Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 09/54] perf: core/x86: Register a new vector for KVM GUEST PMI Mingwei Zhang
2024-05-07 9:12 ` Peter Zijlstra
2024-05-08 10:06 ` Yanfei Xu
2024-05-06 5:29 ` [PATCH v2 10/54] KVM: x86: Extract x86_set_kvm_irq_handler() function Mingwei Zhang
2024-05-07 9:18 ` Peter Zijlstra
2024-05-08 8:57 ` Zhang, Xiong Y
2024-05-06 5:29 ` [PATCH v2 11/54] KVM: x86/pmu: Register guest pmi handler for emulated PMU Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 12/54] perf: x86: Add x86 function to switch PMI handler Mingwei Zhang
2024-05-07 9:22 ` Peter Zijlstra
2024-05-08 6:58 ` Zhang, Xiong Y
2024-05-08 8:37 ` Peter Zijlstra
2024-05-09 7:30 ` Zhang, Xiong Y
2024-05-07 21:40 ` Chen, Zide
2024-05-08 3:44 ` Mi, Dapeng
2024-05-30 5:12 ` Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 13/54] perf: core/x86: Forbid PMI handler when guest own PMU Mingwei Zhang
2024-05-07 9:33 ` Peter Zijlstra
2024-05-09 7:39 ` Zhang, Xiong Y
2024-05-06 5:29 ` [PATCH v2 14/54] perf: core/x86: Plumb passthrough PMU capability from x86_pmu to x86_pmu_cap Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 15/54] KVM: x86/pmu: Introduce enable_passthrough_pmu module parameter Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 16/54] KVM: x86/pmu: Plumb through pass-through PMU to vcpu for Intel CPUs Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 17/54] KVM: x86/pmu: Always set global enable bits in passthrough mode Mingwei Zhang
2024-05-08 4:18 ` Mi, Dapeng
2024-05-08 4:36 ` Mingwei Zhang
2024-05-08 6:27 ` Mi, Dapeng
2024-05-08 14:13 ` Sean Christopherson
2024-05-09 0:13 ` Mingwei Zhang
2024-05-09 0:30 ` Mi, Dapeng
2024-05-09 0:38 ` Mi, Dapeng
2024-05-06 5:29 ` [PATCH v2 18/54] KVM: x86/pmu: Add a helper to check if passthrough PMU is enabled Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 19/54] KVM: x86/pmu: Add host_perf_cap and initialize it in kvm_x86_vendor_init() Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 20/54] KVM: x86/pmu: Allow RDPMC pass through when all counters exposed to guest Mingwei Zhang
2024-05-08 21:55 ` Chen, Zide
2024-05-30 5:20 ` Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 21/54] KVM: x86/pmu: Introduce macro PMU_CAP_PERF_METRICS Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 22/54] KVM: x86/pmu: Introduce PMU operator to check if rdpmc passthrough allowed Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 23/54] KVM: x86/pmu: Manage MSR interception for IA32_PERF_GLOBAL_CTRL Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 24/54] KVM: x86/pmu: Create a function prototype to disable MSR interception Mingwei Zhang
2024-05-08 22:03 ` Chen, Zide
2024-05-30 5:24 ` Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 25/54] KVM: x86/pmu: Add intel_passthrough_pmu_msrs() to pass-through PMU MSRs Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 26/54] KVM: x86/pmu: Avoid legacy vPMU code when accessing global_ctrl in passthrough vPMU Mingwei Zhang
2024-05-08 21:48 ` Chen, Zide
2024-05-09 0:43 ` Mi, Dapeng
2024-05-09 1:29 ` Chen, Zide [this message]
2024-05-09 2:58 ` Mi, Dapeng
2024-05-30 5:28 ` Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 27/54] KVM: x86/pmu: Exclude PMU MSRs in vmx_get_passthrough_msr_slot() Mingwei Zhang
2024-05-14 7:33 ` Mi, Dapeng
2024-05-06 5:29 ` [PATCH v2 28/54] KVM: x86/pmu: Add counter MSR and selector MSR index into struct kvm_pmc Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 29/54] KVM: x86/pmu: Introduce PMU operation prototypes for save/restore PMU context Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 30/54] KVM: x86/pmu: Implement the save/restore of PMU state for Intel CPU Mingwei Zhang
2024-05-14 8:08 ` Mi, Dapeng
2024-05-30 5:34 ` Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 31/54] KVM: x86/pmu: Make check_pmu_event_filter() an exported function Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 32/54] KVM: x86/pmu: Allow writing to event selector for GP counters if event is allowed Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 33/54] KVM: x86/pmu: Allow writing to fixed counter selector if counter is exposed Mingwei Zhang
2024-05-06 5:29 ` [PATCH v2 34/54] KVM: x86/pmu: Switch IA32_PERF_GLOBAL_CTRL at VM boundary Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 35/54] KVM: x86/pmu: Exclude existing vLBR logic from the passthrough PMU Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 36/54] KVM: x86/pmu: Switch PMI handler at KVM context switch boundary Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 37/54] KVM: x86/pmu: Grab x86 core PMU for passthrough PMU VM Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 38/54] KVM: x86/pmu: Call perf_guest_enter() at PMU context switch Mingwei Zhang
2024-05-07 9:39 ` Peter Zijlstra
2024-05-08 4:22 ` Mi, Dapeng
2024-05-30 4:34 ` Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 39/54] KVM: x86/pmu: Add support for PMU context switch at VM-exit/enter Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 40/54] KVM: x86/pmu: Introduce PMU operator to increment counter Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 41/54] KVM: x86/pmu: Introduce PMU operator for setting counter overflow Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 42/54] KVM: x86/pmu: Implement emulated counter increment for passthrough PMU Mingwei Zhang
2024-05-08 18:28 ` Chen, Zide
2024-05-09 1:11 ` Mi, Dapeng
2024-05-30 4:20 ` Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 43/54] KVM: x86/pmu: Update pmc_{read,write}_counter() to disconnect perf API Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 44/54] KVM: x86/pmu: Disconnect counter reprogram logic from passthrough PMU Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 45/54] KVM: nVMX: Add nested virtualization support for " Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 46/54] perf/x86/amd/core: Set passthrough capability for host Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 47/54] KVM: x86/pmu/svm: Set passthrough capability for vcpus Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 48/54] KVM: x86/pmu/svm: Set enable_passthrough_pmu module parameter Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 49/54] KVM: x86/pmu/svm: Allow RDPMC pass through when all counters exposed to guest Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 50/54] KVM: x86/pmu/svm: Implement callback to disable MSR interception Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 51/54] KVM: x86/pmu/svm: Set GuestOnly bit and clear HostOnly bit when guest write to event selectors Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 52/54] KVM: x86/pmu/svm: Add registers to direct access list Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 53/54] KVM: x86/pmu/svm: Implement handlers to save and restore context Mingwei Zhang
2024-05-06 5:30 ` [PATCH v2 54/54] KVM: x86/pmu/svm: Wire up PMU filtering functionality for passthrough PMU Mingwei Zhang
2024-05-28 2:35 ` [PATCH v2 00/54] Mediated Passthrough vPMU 2.0 for x86 Ma, Yongwei
2024-05-30 4:28 ` Mingwei Zhang
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