From: Krish Sadhukhan <krish.sadhukhan@oracle.com>
To: Sean Christopherson <seanjc@google.com>
Cc: kvm@vger.kernel.org, pbonzini@redhat.com, jmattson@google.com
Subject: Re: [PATCH 4/4 v2] KVM: x86: Add a new VM statistic to show number of VCPUs created in a given VM
Date: Fri, 21 May 2021 11:06:00 -0700 [thread overview]
Message-ID: <e7c6c2c8-87e5-96ca-5ec6-d28dda16b603@oracle.com> (raw)
In-Reply-To: <YKZ6a6UlJt/r985F@google.com>
On 5/20/21 8:04 AM, Sean Christopherson wrote:
> On Wed, May 19, 2021, Krish Sadhukhan wrote:
>> 'struct kvm' already has a member for counting the number of VCPUs created
>> for a given VM. Add this as a new VM statistic to KVM debugfs.
> Huh!?? Why? Userspace is the one creating the vCPUs, it darn well should know
> how many it's created.
>
If I am providing a host for users to create VMs, how do I know who
creates how many VCPUs ? This statistic is intended show usage of VCPU
resources on a host used by customers.
>> Signed-off-by: Krish Sadhukhan <Krish.Sadhukhan@oracle.com>
>> ---
>> arch/x86/include/asm/kvm_host.h | 1 +
>> arch/x86/kvm/svm/svm.c | 3 +--
>> arch/x86/kvm/x86.c | 1 +
>> virt/kvm/kvm_main.c | 2 ++
>> 4 files changed, 5 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
>> index a19fe2cfaa93..69ca1d6f6557 100644
>> --- a/arch/x86/include/asm/kvm_host.h
>> +++ b/arch/x86/include/asm/kvm_host.h
>> @@ -1139,6 +1139,7 @@ struct kvm_vm_stat {
>> ulong nx_lpage_splits;
>> ulong max_mmu_page_hash_collisions;
>> ulong vcpus_ran_nested;
>> + u64 created_vcpus;
>> };
>>
>> struct kvm_vcpu_stat {
>> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
>> index d1871c51411f..fef0baba043b 100644
>> --- a/arch/x86/kvm/svm/svm.c
>> +++ b/arch/x86/kvm/svm/svm.c
>> @@ -3875,8 +3875,7 @@ 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_ERR) {
> ???
Sorry, this one sneaked in here from the other patch! Will remove it.
>
>> if (!vcpu->stat.nested_runs)
>> ++vcpu->kvm->stat.vcpus_ran_nested;
>> ++vcpu->stat.nested_runs;
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index cbca3609a152..a9d27ce4cc93 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -258,6 +258,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
>> 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),
>> + VM_STAT("created_vcpus", created_vcpus),
>> { NULL }
>> };
>>
>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
>> index 6b4feb92dc79..ac8f02d8a051 100644
>> --- a/virt/kvm/kvm_main.c
>> +++ b/virt/kvm/kvm_main.c
>> @@ -3318,6 +3318,7 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
>> }
>>
>> kvm->created_vcpus++;
>> + kvm->stat.created_vcpus++;
>> mutex_unlock(&kvm->lock);
>>
>> r = kvm_arch_vcpu_precreate(kvm, id);
>> @@ -3394,6 +3395,7 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
>> vcpu_decrement:
>> mutex_lock(&kvm->lock);
>> kvm->created_vcpus--;
>> + kvm->stat.created_vcpus--;
>> mutex_unlock(&kvm->lock);
>> return r;
>> }
>> --
>> 2.27.0
>>
next prev parent reply other threads:[~2021-05-21 18:06 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-20 0:50 [PATCH 0/4 v2] KVM: nVMX: nSVM: Add more statistics to KVM debugfs Krish Sadhukhan
2021-05-20 0:50 ` [PATCH 1/4 v2] KVM: nVMX: Reset 'nested_run_pending' only in guest mode Krish Sadhukhan
2021-05-20 15:00 ` Sean Christopherson
2021-05-20 0:50 ` [PATCH 2/4 v2] KVM: nVMX: nSVM: 'nested_run' should count guest-entry attempts that make it to guest code Krish Sadhukhan
2021-05-20 14:53 ` Sean Christopherson
2021-05-20 17:58 ` Krish Sadhukhan
2021-05-20 0:50 ` [PATCH 3/4 v2] KVM: nVMX: nSVM: Add a new debugfs statistic to show how many VCPUs have run nested guests Krish Sadhukhan
2021-05-20 14:56 ` Sean Christopherson
2021-05-20 16:57 ` Jim Mattson
2021-05-20 18:01 ` Krish Sadhukhan
2021-05-20 0:50 ` [PATCH 4/4 v2] KVM: x86: Add a new VM statistic to show number of VCPUs created in a given VM Krish Sadhukhan
2021-05-20 15:04 ` Sean Christopherson
2021-05-21 18:06 ` Krish Sadhukhan [this message]
2021-05-27 17:46 ` Sean Christopherson
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