Message ID | 20240326094035.115835-1-gautam@linux.ibm.com (mailing list archive) |
---|---|
State | Superseded |
Headers | show |
Series | [v4] arch/powerpc/kvm: Add support for reading VPA counters for pseries guests | expand |
Context | Check | Description |
---|---|---|
snowpatch_ozlabs/github-powerpc_kernel_qemu | fail | kernel (mpc885_ads_defconfig, fedora-38) failed at step Build. |
snowpatch_ozlabs/github-powerpc_ppctests | success | Successfully ran 8 jobs. |
snowpatch_ozlabs/github-powerpc_selftests | success | Successfully ran 8 jobs. |
snowpatch_ozlabs/github-powerpc_sparse | success | Successfully ran 4 jobs. |
snowpatch_ozlabs/github-powerpc_clang | success | Successfully ran 6 jobs. |
On 3/26/24 3:10 PM, Gautam Menghani wrote: > PAPR hypervisor has introduced three new counters in the VPA area of > LPAR CPUs for KVM L2 guest (see [1] for terminology) observability - 2 > for context switches from host to guest and vice versa, and 1 counter > for getting the total time spent inside the KVM guest. Add a tracepoint > that enables reading the counters for use by ftrace/perf. Note that this > tracepoint is only available for nestedv2 API (i.e, KVM on PowerVM). > > Also maintain an aggregation of the context switch times in vcpu->arch. > This will be useful in getting the aggregate times with a pmu driver > which will be upstreamed in the near future. > > [1] Terminology: > a. L1 refers to the VM (LPAR) booted on top of PAPR hypervisor > b. L2 refers to the KVM guest booted on top of L1. > > Signed-off-by: Vaibhav Jain<vaibhav@linux.ibm.com> > Signed-off-by: Gautam Menghani<gautam@linux.ibm.com> > --- > v1 -> v2: > 1. Fix the build error due to invalid struct member reference. > > v2 -> v3: > 1. Move the counter disabling and zeroing code to a different function. > 2. Move the get_lppaca() inside the tracepoint_enabled() branch. > 3. Add the aggregation logic to maintain total context switch time. > > v3 -> v4: > 1. After vcpu_run, check the VPA flag instead of checking for tracepoint > being enabled for disabling the cs time accumulation. > > arch/powerpc/include/asm/kvm_host.h | 5 +++++ > arch/powerpc/include/asm/lppaca.h | 11 ++++++++--- > arch/powerpc/kvm/book3s_hv.c | 30 +++++++++++++++++++++++++++++ > arch/powerpc/kvm/trace_hv.h | 25 ++++++++++++++++++++++++ > 4 files changed, 68 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h > index 8abac5321..d953b32dd 100644 > --- a/arch/powerpc/include/asm/kvm_host.h > +++ b/arch/powerpc/include/asm/kvm_host.h > @@ -847,6 +847,11 @@ struct kvm_vcpu_arch { > gpa_t nested_io_gpr; > /* For nested APIv2 guests*/ > struct kvmhv_nestedv2_io nestedv2_io; > + > + /* Aggregate context switch and guest run time info (in ns) */ > + u64 l1_to_l2_cs_agg; > + u64 l2_to_l1_cs_agg; > + u64 l2_runtime_agg; > #endif > > #ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING > diff --git a/arch/powerpc/include/asm/lppaca.h b/arch/powerpc/include/asm/lppaca.h > index 61ec2447d..bda6b86b9 100644 > --- a/arch/powerpc/include/asm/lppaca.h > +++ b/arch/powerpc/include/asm/lppaca.h > @@ -62,7 +62,8 @@ struct lppaca { > u8 donate_dedicated_cpu; /* Donate dedicated CPU cycles */ > u8 fpregs_in_use; > u8 pmcregs_in_use; > - u8 reserved8[28]; > + u8 l2_accumul_cntrs_enable; /* Enable usage of counters for KVM guest */ > + u8 reserved8[27]; > __be64 wait_state_cycles; /* Wait cycles for this proc */ > u8 reserved9[28]; > __be16 slb_count; /* # of SLBs to maintain */ > @@ -92,9 +93,13 @@ struct lppaca { > /* cacheline 4-5 */ > > __be32 page_ins; /* CMO Hint - # page ins by OS */ > - u8 reserved12[148]; > + u8 reserved12[28]; > + volatile __be64 l1_to_l2_cs_tb; > + volatile __be64 l2_to_l1_cs_tb; > + volatile __be64 l2_runtime_tb; > + u8 reserved13[96]; > volatile __be64 dtl_idx; /* Dispatch Trace Log head index */ > - u8 reserved13[96]; > + u8 reserved14[96]; > } ____cacheline_aligned; > > #define lppaca_of(cpu) (*paca_ptrs[cpu]->lppaca_ptr) > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c > index 8e86eb577..dcd6edd3b 100644 > --- a/arch/powerpc/kvm/book3s_hv.c > +++ b/arch/powerpc/kvm/book3s_hv.c > @@ -4108,6 +4108,27 @@ static void vcpu_vpa_increment_dispatch(struct kvm_vcpu *vcpu) > } > } > > +static void do_trace_nested_cs_time(struct kvm_vcpu *vcpu) > +{ > + struct lppaca *lp = get_lppaca(); > + u64 l1_to_l2_ns, l2_to_l1_ns, l2_runtime_ns; > + > + l1_to_l2_ns = tb_to_ns(be64_to_cpu(lp->l1_to_l2_cs_tb)); > + l2_to_l1_ns = tb_to_ns(be64_to_cpu(lp->l2_to_l1_cs_tb)); > + l2_runtime_ns = tb_to_ns(be64_to_cpu(lp->l2_runtime_tb)); > + trace_kvmppc_vcpu_exit_cs_time(vcpu, l1_to_l2_ns, l2_to_l1_ns, > + l2_runtime_ns); > + lp->l1_to_l2_cs_tb = 0; > + lp->l2_to_l1_cs_tb = 0; > + lp->l2_runtime_tb = 0; > + lp->l2_accumul_cntrs_enable = 0; > + > + // Maintain an aggregate of context switch times > + vcpu->arch.l1_to_l2_cs_agg += l1_to_l2_ns; > + vcpu->arch.l2_to_l1_cs_agg += l2_to_l1_ns; > + vcpu->arch.l2_runtime_agg += l2_runtime_ns; > +} > + > static int kvmhv_vcpu_entry_nestedv2(struct kvm_vcpu *vcpu, u64 time_limit, > unsigned long lpcr, u64 *tb) > { > @@ -4130,6 +4151,11 @@ static int kvmhv_vcpu_entry_nestedv2(struct kvm_vcpu *vcpu, u64 time_limit, > kvmppc_gse_put_u64(io->vcpu_run_input, KVMPPC_GSID_LPCR, lpcr); > > accumulate_time(vcpu, &vcpu->arch.in_guest); > + > + /* Enable the guest host context switch time tracking */ > + if (unlikely(trace_kvmppc_vcpu_exit_cs_time_enabled())) > + get_lppaca()->l2_accumul_cntrs_enable = 1; can we wrap "get_lppaca()->l2_accumul_cntrs_enable" under wrapper function like is_l2_accumul_cntrs_enable(), set_l2_accumul_cntrs_enable() and unset_l2_accumul_cntrs_enable()? set/unset does not need a parameter and in future incase if we want to check and set or check and unset, we could have additional code in there. Maddy > + > rc = plpar_guest_run_vcpu(0, vcpu->kvm->arch.lpid, vcpu->vcpu_id, > &trap, &i); > > @@ -4156,6 +4182,10 @@ static int kvmhv_vcpu_entry_nestedv2(struct kvm_vcpu *vcpu, u64 time_limit, > > timer_rearm_host_dec(*tb); > > + /* Record context switch and guest_run_time data */ > + if (get_lppaca()->l2_accumul_cntrs_enable) > + do_trace_nested_cs_time(vcpu); > + > return trap; > } > > diff --git a/arch/powerpc/kvm/trace_hv.h b/arch/powerpc/kvm/trace_hv.h > index 8d57c8428..ab19977c9 100644 > --- a/arch/powerpc/kvm/trace_hv.h > +++ b/arch/powerpc/kvm/trace_hv.h > @@ -491,6 +491,31 @@ TRACE_EVENT(kvmppc_run_vcpu_enter, > TP_printk("VCPU %d: tgid=%d", __entry->vcpu_id, __entry->tgid) > ); > > +TRACE_EVENT(kvmppc_vcpu_exit_cs_time, > + TP_PROTO(struct kvm_vcpu *vcpu, u64 l1_to_l2_cs, u64 l2_to_l1_cs, > + u64 l2_runtime), > + > + TP_ARGS(vcpu, l1_to_l2_cs, l2_to_l1_cs, l2_runtime), > + > + TP_STRUCT__entry( > + __field(int, vcpu_id) > + __field(__u64, l1_to_l2_cs_ns) > + __field(__u64, l2_to_l1_cs_ns) > + __field(__u64, l2_runtime_ns) > + ), > + > + TP_fast_assign( > + __entry->vcpu_id = vcpu->vcpu_id; > + __entry->l1_to_l2_cs_ns = l1_to_l2_cs; > + __entry->l2_to_l1_cs_ns = l2_to_l1_cs; > + __entry->l2_runtime_ns = l2_runtime; > + ), > + > + TP_printk("VCPU %d: l1_to_l2_cs_time=%llu-ns l2_to_l1_cs_time=%llu-ns l2_runtime=%llu-ns", > + __entry->vcpu_id, __entry->l1_to_l2_cs_ns, > + __entry->l2_to_l1_cs_ns, __entry->l2_runtime_ns) > +); > + > TRACE_EVENT(kvmppc_run_vcpu_exit, > TP_PROTO(struct kvm_vcpu *vcpu), >
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 8abac5321..d953b32dd 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -847,6 +847,11 @@ struct kvm_vcpu_arch { gpa_t nested_io_gpr; /* For nested APIv2 guests*/ struct kvmhv_nestedv2_io nestedv2_io; + + /* Aggregate context switch and guest run time info (in ns) */ + u64 l1_to_l2_cs_agg; + u64 l2_to_l1_cs_agg; + u64 l2_runtime_agg; #endif #ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING diff --git a/arch/powerpc/include/asm/lppaca.h b/arch/powerpc/include/asm/lppaca.h index 61ec2447d..bda6b86b9 100644 --- a/arch/powerpc/include/asm/lppaca.h +++ b/arch/powerpc/include/asm/lppaca.h @@ -62,7 +62,8 @@ struct lppaca { u8 donate_dedicated_cpu; /* Donate dedicated CPU cycles */ u8 fpregs_in_use; u8 pmcregs_in_use; - u8 reserved8[28]; + u8 l2_accumul_cntrs_enable; /* Enable usage of counters for KVM guest */ + u8 reserved8[27]; __be64 wait_state_cycles; /* Wait cycles for this proc */ u8 reserved9[28]; __be16 slb_count; /* # of SLBs to maintain */ @@ -92,9 +93,13 @@ struct lppaca { /* cacheline 4-5 */ __be32 page_ins; /* CMO Hint - # page ins by OS */ - u8 reserved12[148]; + u8 reserved12[28]; + volatile __be64 l1_to_l2_cs_tb; + volatile __be64 l2_to_l1_cs_tb; + volatile __be64 l2_runtime_tb; + u8 reserved13[96]; volatile __be64 dtl_idx; /* Dispatch Trace Log head index */ - u8 reserved13[96]; + u8 reserved14[96]; } ____cacheline_aligned; #define lppaca_of(cpu) (*paca_ptrs[cpu]->lppaca_ptr) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 8e86eb577..dcd6edd3b 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -4108,6 +4108,27 @@ static void vcpu_vpa_increment_dispatch(struct kvm_vcpu *vcpu) } } +static void do_trace_nested_cs_time(struct kvm_vcpu *vcpu) +{ + struct lppaca *lp = get_lppaca(); + u64 l1_to_l2_ns, l2_to_l1_ns, l2_runtime_ns; + + l1_to_l2_ns = tb_to_ns(be64_to_cpu(lp->l1_to_l2_cs_tb)); + l2_to_l1_ns = tb_to_ns(be64_to_cpu(lp->l2_to_l1_cs_tb)); + l2_runtime_ns = tb_to_ns(be64_to_cpu(lp->l2_runtime_tb)); + trace_kvmppc_vcpu_exit_cs_time(vcpu, l1_to_l2_ns, l2_to_l1_ns, + l2_runtime_ns); + lp->l1_to_l2_cs_tb = 0; + lp->l2_to_l1_cs_tb = 0; + lp->l2_runtime_tb = 0; + lp->l2_accumul_cntrs_enable = 0; + + // Maintain an aggregate of context switch times + vcpu->arch.l1_to_l2_cs_agg += l1_to_l2_ns; + vcpu->arch.l2_to_l1_cs_agg += l2_to_l1_ns; + vcpu->arch.l2_runtime_agg += l2_runtime_ns; +} + static int kvmhv_vcpu_entry_nestedv2(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpcr, u64 *tb) { @@ -4130,6 +4151,11 @@ static int kvmhv_vcpu_entry_nestedv2(struct kvm_vcpu *vcpu, u64 time_limit, kvmppc_gse_put_u64(io->vcpu_run_input, KVMPPC_GSID_LPCR, lpcr); accumulate_time(vcpu, &vcpu->arch.in_guest); + + /* Enable the guest host context switch time tracking */ + if (unlikely(trace_kvmppc_vcpu_exit_cs_time_enabled())) + get_lppaca()->l2_accumul_cntrs_enable = 1; + rc = plpar_guest_run_vcpu(0, vcpu->kvm->arch.lpid, vcpu->vcpu_id, &trap, &i); @@ -4156,6 +4182,10 @@ static int kvmhv_vcpu_entry_nestedv2(struct kvm_vcpu *vcpu, u64 time_limit, timer_rearm_host_dec(*tb); + /* Record context switch and guest_run_time data */ + if (get_lppaca()->l2_accumul_cntrs_enable) + do_trace_nested_cs_time(vcpu); + return trap; } diff --git a/arch/powerpc/kvm/trace_hv.h b/arch/powerpc/kvm/trace_hv.h index 8d57c8428..ab19977c9 100644 --- a/arch/powerpc/kvm/trace_hv.h +++ b/arch/powerpc/kvm/trace_hv.h @@ -491,6 +491,31 @@ TRACE_EVENT(kvmppc_run_vcpu_enter, TP_printk("VCPU %d: tgid=%d", __entry->vcpu_id, __entry->tgid) ); +TRACE_EVENT(kvmppc_vcpu_exit_cs_time, + TP_PROTO(struct kvm_vcpu *vcpu, u64 l1_to_l2_cs, u64 l2_to_l1_cs, + u64 l2_runtime), + + TP_ARGS(vcpu, l1_to_l2_cs, l2_to_l1_cs, l2_runtime), + + TP_STRUCT__entry( + __field(int, vcpu_id) + __field(__u64, l1_to_l2_cs_ns) + __field(__u64, l2_to_l1_cs_ns) + __field(__u64, l2_runtime_ns) + ), + + TP_fast_assign( + __entry->vcpu_id = vcpu->vcpu_id; + __entry->l1_to_l2_cs_ns = l1_to_l2_cs; + __entry->l2_to_l1_cs_ns = l2_to_l1_cs; + __entry->l2_runtime_ns = l2_runtime; + ), + + TP_printk("VCPU %d: l1_to_l2_cs_time=%llu-ns l2_to_l1_cs_time=%llu-ns l2_runtime=%llu-ns", + __entry->vcpu_id, __entry->l1_to_l2_cs_ns, + __entry->l2_to_l1_cs_ns, __entry->l2_runtime_ns) +); + TRACE_EVENT(kvmppc_run_vcpu_exit, TP_PROTO(struct kvm_vcpu *vcpu),