[PATCH v7 08/12] KVM: arm64: PMU: Allow userspace to limit PMCR_EL0.N for the guest
Sebastian Ott
sebott at redhat.com
Tue Oct 17 08:52:37 PDT 2023
On Mon, 9 Oct 2023, Raghavendra Rao Ananta wrote:
> +static int set_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> + u64 val)
> +{
> + struct kvm *kvm = vcpu->kvm;
> + u64 new_n, mutable_mask;
> +
> + mutex_lock(&kvm->arch.config_lock);
> +
> + /*
> + * Make PMCR immutable once the VM has started running, but do
> + * not return an error (-EBUSY) to meet the existing expectations.
> + */
Why should we mention which error we're _not_ returning?
> + if (kvm_vm_has_ran_once(vcpu->kvm)) {
> + mutex_unlock(&kvm->arch.config_lock);
> + return 0;
> + }
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