| Message ID | 20230214050757.9623-3-likexu@tencent.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86: Add AMD Guest PerfMonV2 PMU support | expand |
On Tue, Feb 14, 2023, Like Xu wrote: > From: Sean Christopherson <seanjc@google.com> > --- > arch/x86/kvm/vmx/pmu_intel.c | 81 +++++++++++++++++++----------------- > 1 file changed, 42 insertions(+), 39 deletions(-) > > diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c > index e8a3be0b9df9..6a2f8b4ed061 100644 > --- a/arch/x86/kvm/vmx/pmu_intel.c > +++ b/arch/x86/kvm/vmx/pmu_intel.c > @@ -402,44 +402,43 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) Gah, I forgot to post a patch that gives intel_pmu_get_msr() the same treatment. I'll replace this patch with the combined version below when applying, or will post it separately if a v5 is needed. From: Sean Christopherson <seanjc@google.com> Date: Thu, 26 Jan 2023 17:08:03 -0800 Subject: [PATCH] KVM: VMX: Refactor intel_pmu_{g,}set_msr() to align with other helpers Invert the flows in intel_pmu_{g,s}et_msr()'s case statements so that they follow the kernel's preferred style of: if (<not valid>) return <error> <commit change> return <success> which is also the style used by every other {g,s}et_msr() helper (except AMD's PMU variant, which doesn't use a switch statement). Modify the "set" paths with costly side effects, i.e. that reprogram counters, to skip only the side effects, i.e. to perform reserved bits checks even if the value is unchanged. None of the reserved bits checks are expensive, so there's no strong justification for skipping them, and guarding only the side effect makes it slightly more obvious what is being skipped and why. No functional change intended (assuming no reserved bit bugs). Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/vmx/pmu_intel.c | 109 ++++++++++++++++++----------------- 1 file changed, 57 insertions(+), 52 deletions(-) diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index e8a3be0b9df9..432662f71207 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -351,45 +351,47 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) switch (msr) { case MSR_CORE_PERF_FIXED_CTR_CTRL: msr_info->data = pmu->fixed_ctr_ctrl; - return 0; + break; case MSR_CORE_PERF_GLOBAL_STATUS: msr_info->data = pmu->global_status; - return 0; + break; case MSR_CORE_PERF_GLOBAL_CTRL: msr_info->data = pmu->global_ctrl; - return 0; + break; case MSR_CORE_PERF_GLOBAL_OVF_CTRL: msr_info->data = 0; - return 0; + break; case MSR_IA32_PEBS_ENABLE: msr_info->data = pmu->pebs_enable; - return 0; + break; case MSR_IA32_DS_AREA: msr_info->data = pmu->ds_area; - return 0; + break; case MSR_PEBS_DATA_CFG: msr_info->data = pmu->pebs_data_cfg; - return 0; + break; default: if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) || (pmc = get_gp_pmc(pmu, msr, MSR_IA32_PMC0))) { u64 val = pmc_read_counter(pmc); msr_info->data = val & pmu->counter_bitmask[KVM_PMC_GP]; - return 0; + break; } else if ((pmc = get_fixed_pmc(pmu, msr))) { u64 val = pmc_read_counter(pmc); msr_info->data = val & pmu->counter_bitmask[KVM_PMC_FIXED]; - return 0; + break; } else if ((pmc = get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0))) { msr_info->data = pmc->eventsel; - return 0; - } else if (intel_pmu_handle_lbr_msrs_access(vcpu, msr_info, true)) - return 0; + break; + } else if (intel_pmu_handle_lbr_msrs_access(vcpu, msr_info, true)) { + break; + } + return 1; } - return 1; + return 0; } static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) @@ -402,44 +404,43 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) switch (msr) { case MSR_CORE_PERF_FIXED_CTR_CTRL: - if (pmu->fixed_ctr_ctrl == data) - return 0; - if (!(data & pmu->fixed_ctr_ctrl_mask)) { + if (data & pmu->fixed_ctr_ctrl_mask) + return 1; + + if (pmu->fixed_ctr_ctrl != data) reprogram_fixed_counters(pmu, data); - return 0; - } break; case MSR_CORE_PERF_GLOBAL_STATUS: - if (msr_info->host_initiated) { - pmu->global_status = data; - return 0; - } - break; /* RO MSR */ + if (!msr_info->host_initiated) + return 1; /* RO MSR */ + + pmu->global_status = data; + break; case MSR_CORE_PERF_GLOBAL_CTRL: - if (pmu->global_ctrl == data) - return 0; - if (kvm_valid_perf_global_ctrl(pmu, data)) { + if (!kvm_valid_perf_global_ctrl(pmu, data)) + return 1; + + if (pmu->global_ctrl != data) { diff = pmu->global_ctrl ^ data; pmu->global_ctrl = data; reprogram_counters(pmu, diff); - return 0; } break; case MSR_CORE_PERF_GLOBAL_OVF_CTRL: - if (!(data & pmu->global_ovf_ctrl_mask)) { - if (!msr_info->host_initiated) - pmu->global_status &= ~data; - return 0; - } + if (data & pmu->global_ovf_ctrl_mask) + return 1; + + if (!msr_info->host_initiated) + pmu->global_status &= ~data; break; case MSR_IA32_PEBS_ENABLE: - if (pmu->pebs_enable == data) - return 0; - if (!(data & pmu->pebs_enable_mask)) { + if (data & pmu->pebs_enable_mask) + return 1; + + if (pmu->pebs_enable != data) { diff = pmu->pebs_enable ^ data; pmu->pebs_enable = data; reprogram_counters(pmu, diff); - return 0; } break; case MSR_IA32_DS_AREA: @@ -447,15 +448,14 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) return 1; if (is_noncanonical_address(data, vcpu)) return 1; + pmu->ds_area = data; - return 0; + break; case MSR_PEBS_DATA_CFG: - if (pmu->pebs_data_cfg == data) - return 0; - if (!(data & pmu->pebs_data_cfg_mask)) { - pmu->pebs_data_cfg = data; - return 0; - } + if (data & pmu->pebs_data_cfg_mask) + return 1; + + pmu->pebs_data_cfg = data; break; default: if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) || @@ -463,33 +463,38 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) if ((msr & MSR_PMC_FULL_WIDTH_BIT) && (data & ~pmu->counter_bitmask[KVM_PMC_GP])) return 1; + if (!msr_info->host_initiated && !(msr & MSR_PMC_FULL_WIDTH_BIT)) data = (s64)(s32)data; pmc->counter += data - pmc_read_counter(pmc); pmc_update_sample_period(pmc); - return 0; + break; } else if ((pmc = get_fixed_pmc(pmu, msr))) { pmc->counter += data - pmc_read_counter(pmc); pmc_update_sample_period(pmc); - return 0; + break; } else if ((pmc = get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0))) { - if (data == pmc->eventsel) - return 0; reserved_bits = pmu->reserved_bits; if ((pmc->idx == 2) && (pmu->raw_event_mask & HSW_IN_TX_CHECKPOINTED)) reserved_bits ^= HSW_IN_TX_CHECKPOINTED; - if (!(data & reserved_bits)) { + if (data & reserved_bits) + return 1; + + if (data != pmc->eventsel) { pmc->eventsel = data; kvm_pmu_request_counter_reprogam(pmc); - return 0; } - } else if (intel_pmu_handle_lbr_msrs_access(vcpu, msr_info, false)) - return 0; + break; + } else if (intel_pmu_handle_lbr_msrs_access(vcpu, msr_info, false)) { + break; + } + /* Not a known PMU MSR. */ + return 1; } - return 1; + return 0; } static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu) base-commit: 62ef199250cd46fb66fe98267137b7f64e0b41b4 --
On 17/2/2023 5:13 am, Sean Christopherson wrote: > Gah, I forgot to post a patch that gives intel_pmu_get_msr() the same treatment. > I'll replace this patch with the combined version below when applying, or will > post it separately if a v5 is needed. It's fine for me to apply this new patch first and then apply the remaining patches with only a tiny rebase effort (tests still remains healthy). More, if you have more comments on any other patches that need changing after the radio silence, please roar at me on this version. > > From: Sean Christopherson<seanjc@google.com> > Date: Thu, 26 Jan 2023 17:08:03 -0800 > Subject: [PATCH] KVM: VMX: Refactor intel_pmu_{g,}set_msr() to align with > other helpers
Hi Sean, the kvm-x86/pmu branch is basically unchanged up to now, do you need a V5 for this feature ? Thanks. On 21/2/2023 4:44 pm, Like Xu wrote: > On 17/2/2023 5:13 am, Sean Christopherson wrote: >> Gah, I forgot to post a patch that gives intel_pmu_get_msr() the same treatment. >> I'll replace this patch with the combined version below when applying, or will >> post it separately if a v5 is needed. > > It's fine for me to apply this new patch first and then apply the remaining > patches with only a tiny rebase effort (tests still remains healthy). More, if > you have more comments on any other patches that need changing after > the radio silence, please roar at me on this version. > >> >> From: Sean Christopherson<seanjc@google.com> >> Date: Thu, 26 Jan 2023 17:08:03 -0800 >> Subject: [PATCH] KVM: VMX: Refactor intel_pmu_{g,}set_msr() to align with >> other helpers >
On Thu, Mar 23, 2023, Like Xu wrote: > Hi Sean, > > the kvm-x86/pmu branch is basically unchanged up to now, > do you need a V5 for this feature ? Thanks. Unknown at this time, I've been fighting fires and am behind where I wanted to be in terms of review for 6.4. I'm partially batching areas this time around for a variety of reasons. Next up is selftests, and PMU is after. Hopefully selftests will go relatively quickly and I'll be able to focus on PMU sometime next week. Sorry for the delay.
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index e8a3be0b9df9..6a2f8b4ed061 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -402,44 +402,43 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) switch (msr) { case MSR_CORE_PERF_FIXED_CTR_CTRL: - if (pmu->fixed_ctr_ctrl == data) - return 0; - if (!(data & pmu->fixed_ctr_ctrl_mask)) { + if (data & pmu->fixed_ctr_ctrl_mask) + return 1; + + if (pmu->fixed_ctr_ctrl != data) reprogram_fixed_counters(pmu, data); - return 0; - } break; case MSR_CORE_PERF_GLOBAL_STATUS: - if (msr_info->host_initiated) { - pmu->global_status = data; - return 0; - } - break; /* RO MSR */ + if (!msr_info->host_initiated) + return 1; /* RO MSR */ + + pmu->global_status = data; + break; case MSR_CORE_PERF_GLOBAL_CTRL: - if (pmu->global_ctrl == data) - return 0; - if (kvm_valid_perf_global_ctrl(pmu, data)) { + if (!kvm_valid_perf_global_ctrl(pmu, data)) + return 1; + + if (pmu->global_ctrl != data) { diff = pmu->global_ctrl ^ data; pmu->global_ctrl = data; reprogram_counters(pmu, diff); - return 0; } break; case MSR_CORE_PERF_GLOBAL_OVF_CTRL: - if (!(data & pmu->global_ovf_ctrl_mask)) { - if (!msr_info->host_initiated) - pmu->global_status &= ~data; - return 0; - } + if (data & pmu->global_ovf_ctrl_mask) + return 1; + + if (!msr_info->host_initiated) + pmu->global_status &= ~data; break; case MSR_IA32_PEBS_ENABLE: - if (pmu->pebs_enable == data) - return 0; - if (!(data & pmu->pebs_enable_mask)) { + if (data & pmu->pebs_enable_mask) + return 1; + + if (pmu->pebs_enable != data) { diff = pmu->pebs_enable ^ data; pmu->pebs_enable = data; reprogram_counters(pmu, diff); - return 0; } break; case MSR_IA32_DS_AREA: @@ -447,15 +446,14 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) return 1; if (is_noncanonical_address(data, vcpu)) return 1; + pmu->ds_area = data; - return 0; + break; case MSR_PEBS_DATA_CFG: - if (pmu->pebs_data_cfg == data) - return 0; - if (!(data & pmu->pebs_data_cfg_mask)) { - pmu->pebs_data_cfg = data; - return 0; - } + if (data & pmu->pebs_data_cfg_mask) + return 1; + + pmu->pebs_data_cfg = data; break; default: if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) || @@ -463,33 +461,38 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) if ((msr & MSR_PMC_FULL_WIDTH_BIT) && (data & ~pmu->counter_bitmask[KVM_PMC_GP])) return 1; + if (!msr_info->host_initiated && !(msr & MSR_PMC_FULL_WIDTH_BIT)) data = (s64)(s32)data; pmc->counter += data - pmc_read_counter(pmc); pmc_update_sample_period(pmc); - return 0; + break; } else if ((pmc = get_fixed_pmc(pmu, msr))) { pmc->counter += data - pmc_read_counter(pmc); pmc_update_sample_period(pmc); - return 0; + break; } else if ((pmc = get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0))) { - if (data == pmc->eventsel) - return 0; reserved_bits = pmu->reserved_bits; if ((pmc->idx == 2) && (pmu->raw_event_mask & HSW_IN_TX_CHECKPOINTED)) reserved_bits ^= HSW_IN_TX_CHECKPOINTED; - if (!(data & reserved_bits)) { + if (data & reserved_bits) + return 1; + + if (data != pmc->eventsel) { pmc->eventsel = data; kvm_pmu_request_counter_reprogam(pmc); - return 0; } - } else if (intel_pmu_handle_lbr_msrs_access(vcpu, msr_info, false)) - return 0; + break; + } else if (intel_pmu_handle_lbr_msrs_access(vcpu, msr_info, false)) { + break; + } + /* Not a known PMU MSR. */ + return 1; } - return 1; + return 0; } static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu)