Re: [RFC PATCH v6 05/35] KVM: arm64: Add KVM_CAP_ARM_SPE capability

[Leo Yan <leo.yan@linux.dev>]

On Fri, Nov 14, 2025 at 04:06:46PM +0000, Alexandru Elisei wrote:

[...]

> +void kvm_host_spe_init(struct arm_spe_pmu *arm_spu)
> +{
> +	struct arm_spu_entry *entry;
> +
> +	guard(mutex)(&arm_spus_lock);
> +
> +	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
> +	if (!entry)
> +		return;
> +
> +	entry->arm_spu = arm_spu;
> +	list_add_tail(&entry->link, &arm_spus);
> +
> +	if (list_is_singular(&arm_spus))
> +		static_branch_enable(&kvm_spe_available);

We can simply check if list_empty(&arm_spus) in kvm_supports_spe(), thus
the static key kvm_spe_available is not needed.  Another benefit is this
is consistent with CPU PMU's virt implementation.

Thanks,
Leo