Re: [PATCH v4 05/21] KVM: arm64: Support SDEI_EVENT_{ENABLE, DISABLE} hypercall

Eric Auger
2021-11-09T16:02:17Z

Hi Gavin,

On 8/15/21 2:13 AM, Gavin Shan wrote:
> This supports SDEI_EVENT_{ENABLE, DISABLE} hypercall. After SDEI
> event is registered by guest, it won't be delivered to the guest
> until it's enabled. On the other hand, the SDEI event won't be
> raised to the guest or specific vCPU if it's has been disabled
> on the guest or specific vCPU.
>
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
> arch/arm64/kvm/sdei.c | 68 +++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 68 insertions(+)
>
> diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c
> index d3ea3eee154b..b022ce0a202b 100644
> --- a/arch/arm64/kvm/sdei.c
> +++ b/arch/arm64/kvm/sdei.c
> @@ -206,6 +206,70 @@ static unsigned long kvm_sdei_hypercall_register(struct kvm_vcpu *vcpu)
> return ret;
> }
>
> +static unsigned long kvm_sdei_hypercall_enable(struct kvm_vcpu *vcpu,
> + bool enable)
> +{
> + struct kvm *kvm = vcpu->kvm;
> + struct kvm_sdei_kvm *ksdei = kvm->arch.sdei;
> + struct kvm_sdei_vcpu *vsdei = vcpu->arch.sdei;
> + struct kvm_sdei_event *kse = NULL;
> + struct kvm_sdei_kvm_event *kske = NULL;
> + unsigned long event_num = smccc_get_arg1(vcpu);
> + int index = 0;
> + unsigned long ret = SDEI_SUCCESS;
> +
> + /* Sanity check */
> + if (!(ksdei && vsdei)) {
> + ret = SDEI_NOT_SUPPORTED;
> + goto out;
> + }
> +
> + if (!kvm_sdei_is_valid_event_num(event_num)) {
I would rename into is_exposed_event_num()
> + ret = SDEI_INVALID_PARAMETERS;
> + goto out;
> + }
> +
> + /* Check if the KVM event exists */
> + spin_lock(&ksdei->lock);
> + kske = kvm_sdei_find_kvm_event(kvm, event_num);
> + if (!kske) {
> + ret = SDEI_INVALID_PARAMETERS;
should be DENIED according to the spec, ie. nobody registered that event?
> + goto unlock;
> + }
> +
> + /* Check if there is pending events */
does that match the "handler-unregister-pending state" case mentionned
in the spec?
> + if (kske->state.refcount) {
> + ret = SDEI_PENDING;
? not documented in my A spec? DENIED?
> + goto unlock;
> + }
> +
> + /* Check if it has been registered */
isn't duplicate of /* Check if the KVM event exists */ ?
> + kse = kske->kse;
> + index = (kse->state.type == SDEI_EVENT_TYPE_PRIVATE) ?
> + vcpu->vcpu_idx : 0;
> + if (!kvm_sdei_is_registered(kske, index)) {
> + ret = SDEI_DENIED;
> + goto unlock;
> + }
> +
> + /* Verify its enablement state */
> + if (enable == kvm_sdei_is_enabled(kske, index)) {
spec says:
Enabling/disabled an event, which is already enabled/disabled, is
permitted and has no effect. I guess ret should be OK.
> + ret = SDEI_DENIED;
> + goto unlock;
> + }
> +
> + /* Update enablement state */
> + if (enable)
> + kvm_sdei_set_enabled(kske, index);
> + else
> + kvm_sdei_clear_enabled(kske, index);
> +
> +unlock:
> + spin_unlock(&ksdei->lock);
> +out:
> + return ret;
> +}
> +
> int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
> {
> u32 func = smccc_get_function(vcpu);
> @@ -220,7 +284,11 @@ int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
> ret = kvm_sdei_hypercall_register(vcpu);
> break;
> case SDEI_1_0_FN_SDEI_EVENT_ENABLE:
> + ret = kvm_sdei_hypercall_enable(vcpu, true);
> + break;
> case SDEI_1_0_FN_SDEI_EVENT_DISABLE:
> + ret = kvm_sdei_hypercall_enable(vcpu, false);
> + break;
> case SDEI_1_0_FN_SDEI_EVENT_CONTEXT:
> case SDEI_1_0_FN_SDEI_EVENT_COMPLETE:
> case SDEI_1_0_FN_SDEI_EVENT_COMPLETE_AND_RESUME:
>
Eric