| Message ID | 20210520005012.68377-4-krish.sadhukhan@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: nVMX: nSVM: Add more statistics to KVM debugfs | expand |
On Wed, May 19, 2021, Krish Sadhukhan wrote: > Add a new debugfs statistic to show how many VCPUs have run nested guests. > This statistic considers only the first time a given VCPU successfully runs > a nested guest. > > Signed-off-by: Krish Sadhukhan <Krish.Sadhukhan@oracle.com> > Suggested-by: Jim Mattson <jmattson@google.com> > --- > arch/x86/include/asm/kvm_host.h | 1 + > arch/x86/kvm/svm/svm.c | 5 ++++- > arch/x86/kvm/vmx/vmx.c | 5 ++++- > arch/x86/kvm/x86.c | 1 + > 4 files changed, 10 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index cf8557b2b90f..a19fe2cfaa93 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -1138,6 +1138,7 @@ struct kvm_vm_stat { > ulong lpages; > ulong nx_lpage_splits; > ulong max_mmu_page_hash_collisions; > + ulong vcpus_ran_nested; > }; > > struct kvm_vcpu_stat { > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index 57c351640355..d1871c51411f 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -3876,8 +3876,11 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) > /* Track VMRUNs that have made past consistency checking */ > if (svm->nested.nested_run_pending && > svm->vmcb->control.exit_code != SVM_EXIT_ERR && > - svm->vmcb->control.exit_code != SVM_EXIT_NPF) > + svm->vmcb->control.exit_code != SVM_EXIT_NPF) { > + if (!vcpu->stat.nested_runs) > + ++vcpu->kvm->stat.vcpus_ran_nested; Using a separate counter seems unnecessary, userspace can aggregate vcpu->stat.nested_run itself to see how many vCPUs have done nested VM-Enter. Jim, were you thinking of something else? Am I missing something?
On Thu, May 20, 2021 at 7:56 AM Sean Christopherson <seanjc@google.com> wrote: > > On Wed, May 19, 2021, Krish Sadhukhan wrote: > > Add a new debugfs statistic to show how many VCPUs have run nested guests. > > This statistic considers only the first time a given VCPU successfully runs > > a nested guest. > > > > Signed-off-by: Krish Sadhukhan <Krish.Sadhukhan@oracle.com> > > Suggested-by: Jim Mattson <jmattson@google.com> > > --- > > arch/x86/include/asm/kvm_host.h | 1 + > > arch/x86/kvm/svm/svm.c | 5 ++++- > > arch/x86/kvm/vmx/vmx.c | 5 ++++- > > arch/x86/kvm/x86.c | 1 + > > 4 files changed, 10 insertions(+), 2 deletions(-) > > > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > > index cf8557b2b90f..a19fe2cfaa93 100644 > > --- a/arch/x86/include/asm/kvm_host.h > > +++ b/arch/x86/include/asm/kvm_host.h > > @@ -1138,6 +1138,7 @@ struct kvm_vm_stat { > > ulong lpages; > > ulong nx_lpage_splits; > > ulong max_mmu_page_hash_collisions; > > + ulong vcpus_ran_nested; > > }; > > > > struct kvm_vcpu_stat { > > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > > index 57c351640355..d1871c51411f 100644 > > --- a/arch/x86/kvm/svm/svm.c > > +++ b/arch/x86/kvm/svm/svm.c > > @@ -3876,8 +3876,11 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) > > /* Track VMRUNs that have made past consistency checking */ > > if (svm->nested.nested_run_pending && > > svm->vmcb->control.exit_code != SVM_EXIT_ERR && > > - svm->vmcb->control.exit_code != SVM_EXIT_NPF) > > + svm->vmcb->control.exit_code != SVM_EXIT_NPF) { > > + if (!vcpu->stat.nested_runs) > > + ++vcpu->kvm->stat.vcpus_ran_nested; > > Using a separate counter seems unnecessary, userspace can aggregate > vcpu->stat.nested_run itself to see how many vCPUs have done nested VM-Enter. > > Jim, were you thinking of something else? Am I missing something? It was in the context of a proposed stat to indicate how many vCPUs are *currently* running nested guests that I said I'd rather just know how many vCPUs had *ever* run nested guests. I don't need a separate stat. Checking vcpu->stat.nested_run for non-zero values works fine for me.
On 5/20/21 9:57 AM, Jim Mattson wrote: > On Thu, May 20, 2021 at 7:56 AM Sean Christopherson <seanjc@google.com> wrote: >> On Wed, May 19, 2021, Krish Sadhukhan wrote: >>> Add a new debugfs statistic to show how many VCPUs have run nested guests. >>> This statistic considers only the first time a given VCPU successfully runs >>> a nested guest. >>> >>> Signed-off-by: Krish Sadhukhan <Krish.Sadhukhan@oracle.com> >>> Suggested-by: Jim Mattson <jmattson@google.com> >>> --- >>> arch/x86/include/asm/kvm_host.h | 1 + >>> arch/x86/kvm/svm/svm.c | 5 ++++- >>> arch/x86/kvm/vmx/vmx.c | 5 ++++- >>> arch/x86/kvm/x86.c | 1 + >>> 4 files changed, 10 insertions(+), 2 deletions(-) >>> >>> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h >>> index cf8557b2b90f..a19fe2cfaa93 100644 >>> --- a/arch/x86/include/asm/kvm_host.h >>> +++ b/arch/x86/include/asm/kvm_host.h >>> @@ -1138,6 +1138,7 @@ struct kvm_vm_stat { >>> ulong lpages; >>> ulong nx_lpage_splits; >>> ulong max_mmu_page_hash_collisions; >>> + ulong vcpus_ran_nested; >>> }; >>> >>> struct kvm_vcpu_stat { >>> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c >>> index 57c351640355..d1871c51411f 100644 >>> --- a/arch/x86/kvm/svm/svm.c >>> +++ b/arch/x86/kvm/svm/svm.c >>> @@ -3876,8 +3876,11 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) >>> /* Track VMRUNs that have made past consistency checking */ >>> if (svm->nested.nested_run_pending && >>> svm->vmcb->control.exit_code != SVM_EXIT_ERR && >>> - svm->vmcb->control.exit_code != SVM_EXIT_NPF) >>> + svm->vmcb->control.exit_code != SVM_EXIT_NPF) { >>> + if (!vcpu->stat.nested_runs) >>> + ++vcpu->kvm->stat.vcpus_ran_nested; >> Using a separate counter seems unnecessary, userspace can aggregate >> vcpu->stat.nested_run itself to see how many vCPUs have done nested VM-Enter. >> >> Jim, were you thinking of something else? Am I missing something? > It was in the context of a proposed stat to indicate how many vCPUs > are *currently* running nested guests that I said I'd rather just know > how many vCPUs had *ever* run nested guests. I don't need a separate > stat. Checking vcpu->stat.nested_run for non-zero values works fine > for me. I will fall back to my v1 idea then. That's at least useful if we want to create a time graph of VCPUs running nested guests.
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index cf8557b2b90f..a19fe2cfaa93 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1138,6 +1138,7 @@ struct kvm_vm_stat { ulong lpages; ulong nx_lpage_splits; ulong max_mmu_page_hash_collisions; + ulong vcpus_ran_nested; }; struct kvm_vcpu_stat { diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 57c351640355..d1871c51411f 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3876,8 +3876,11 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) /* Track VMRUNs that have made past consistency checking */ if (svm->nested.nested_run_pending && svm->vmcb->control.exit_code != SVM_EXIT_ERR && - svm->vmcb->control.exit_code != SVM_EXIT_NPF) + svm->vmcb->control.exit_code != SVM_EXIT_NPF) { + if (!vcpu->stat.nested_runs) + ++vcpu->kvm->stat.vcpus_ran_nested; ++vcpu->stat.nested_runs; + } svm->nested.nested_run_pending = 0; } diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index fa8df7ab2756..dc29aa926be6 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6845,8 +6845,11 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu) * checking. */ if (vmx->nested.nested_run_pending && - !vmx->exit_reason.failed_vmentry) + !vmx->exit_reason.failed_vmentry) { + if (!vcpu->stat.nested_runs) + ++vcpu->kvm->stat.vcpus_ran_nested; ++vcpu->stat.nested_runs; + } vmx->nested.nested_run_pending = 0; } diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6d1f51f6c344..cbca3609a152 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -257,6 +257,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { VM_STAT("largepages", lpages, .mode = 0444), VM_STAT("nx_largepages_splitted", nx_lpage_splits, .mode = 0444), VM_STAT("max_mmu_page_hash_collisions", max_mmu_page_hash_collisions), + VM_STAT("vcpus_ran_nested", vcpus_ran_nested), { NULL } };
Add a new debugfs statistic to show how many VCPUs have run nested guests. This statistic considers only the first time a given VCPU successfully runs a nested guest. Signed-off-by: Krish Sadhukhan <Krish.Sadhukhan@oracle.com> Suggested-by: Jim Mattson <jmattson@google.com> --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/svm/svm.c | 5 ++++- arch/x86/kvm/vmx/vmx.c | 5 ++++- arch/x86/kvm/x86.c | 1 + 4 files changed, 10 insertions(+), 2 deletions(-)