[PATCH 7/7] KVM: arm64: Add irq_inject counter for kvm_stat

[Marc Zyngier]

On Fri, 19 Mar 2021 16:17:11 +0000,
Yoan Picchi <yoan.picchi at arm.com> wrote:
> 
> Add a counter for interrupt injections. That is when kvm relay an
> interrupt to the guest (for instance a timer, or a device interrupt
> like from a network card)
> 
> Signed-off-by: Yoan Picchi <yoan.picchi at arm.com>
> ---
>  arch/arm64/include/asm/kvm_host.h | 2 ++
>  arch/arm64/kvm/arm.c              | 2 ++
>  arch/arm64/kvm/guest.c            | 2 ++
>  arch/arm64/kvm/vgic/vgic.c        | 2 ++
>  4 files changed, 8 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index fa59b669c..253acb8c2 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -551,6 +551,7 @@ struct kvm_vm_stat {
>  	ulong memory_slot_unmaped;
>  	ulong stage2_unmap_vm;
>  	ulong cached_page_invalidated;
> +	ulong irq_inject;
>  };
>  
>  struct kvm_vcpu_stat {
> @@ -567,6 +568,7 @@ struct kvm_vcpu_stat {
>  	u64 mmio_exit_kernel;
>  	u64 regular_page_mapped;
>  	u64 huge_page_mapped;
> +	u64 irq_inject;
>  	u64 exits;
>  };
>  
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index fc4c95dd2..841551f14 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -895,6 +895,8 @@ static int vcpu_interrupt_line(struct kvm_vcpu *vcpu, int number, bool level)
>  	bool set;
>  	unsigned long *hcr;
>  
> +	vcpu->stat.irq_inject++;
> +
>  	if (number == KVM_ARM_IRQ_CPU_IRQ)
>  		bit_index = __ffs(HCR_VI);
>  	else /* KVM_ARM_IRQ_CPU_FIQ */
> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
> index 129c0d53d..f663b03ae 100644
> --- a/arch/arm64/kvm/guest.c
> +++ b/arch/arm64/kvm/guest.c
> @@ -45,6 +45,8 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
>  	VM_STAT("memory_slot_unmaped", memory_slot_unmaped),
>  	VM_STAT("stage2_unmap_vm", stage2_unmap_vm),
>  	VM_STAT("cached_page_invalidated", cached_page_invalidated),
> +	VM_STAT("irq_inject", irq_inject),
> +	VCPU_STAT("irq_inject", irq_inject),
>  	VCPU_STAT("exits", exits),
>  	VCPU_STAT("halt_poll_success_ns", halt_poll_success_ns),
>  	VCPU_STAT("halt_poll_fail_ns", halt_poll_fail_ns),
> diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
> index 1c597c988..9e504243b 100644
> --- a/arch/arm64/kvm/vgic/vgic.c
> +++ b/arch/arm64/kvm/vgic/vgic.c
> @@ -458,6 +458,8 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
>  
>  	raw_spin_lock_irqsave(&irq->irq_lock, flags);
>  
> +	kvm->stat.irq_inject++;
> +
>  	if (!vgic_validate_injection(irq, level, owner)) {

So even if the injection failed, you report an injection? And what
about injection that occur via the MMIO interface? What about direct
injection? What about a level interrupt that is forever high?

	M.

-- 
Without deviation from the norm, progress is not possible.