'struct kvm' already has a member for tracking the number of VCPUs created
in a given VM. Add this as a new VM statistic to KVM debugfs. This statistic
can be a useful metric to track the usage of VCPUs on a host running
customer VMs.
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Krish Sadhukhan <Krish.Sadhukhan@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/x86.c | 1 +
virt/kvm/kvm_main.c | 6 ++++++
3 files changed, 8 insertions(+)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f6d5387bb88f..8f61a3fc3d39 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;
};
struct kvm_vcpu_stat {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index baa953757911..7a1ff3052488 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("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", vcpus),
{ NULL }
};
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 6b4feb92dc79..a129a6734965 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3318,6 +3318,9 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
}
kvm->created_vcpus++;
+#ifdef CONFIG_X86
+ kvm->stat.vcpus++;
+#endif
mutex_unlock(&kvm->lock);
r = kvm_arch_vcpu_precreate(kvm, id);
@@ -3394,6 +3397,9 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
vcpu_decrement:
mutex_lock(&kvm->lock);
kvm->created_vcpus--;
+#ifdef CONFIG_X86
+ kvm->stat.vcpus--;
+#endif
mutex_unlock(&kvm->lock);
return r;
}
--
2.27.0
