Re: [PATCH v4 10/21] KVM: arm64: Support SDEI_EVENT_ROUTING_SET hypercall

Eric Auger
2021-11-09T18:47:59Z

Hi Gavin,
On 8/15/21 2:13 AM, Gavin Shan wrote:
> This supports SDEI_EVENT_ROUTING_SET hypercall. It's used by the
> guest to set route mode and affinity for the registered KVM event.
> It's only valid for the shared events. It's not allowed to do so
> when the corresponding event has been raised to the guest.
>
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
> arch/arm64/kvm/sdei.c | 64 +++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 64 insertions(+)
>
> diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c
> index 5dfa74b093f1..458695c2394f 100644
> --- a/arch/arm64/kvm/sdei.c
> +++ b/arch/arm64/kvm/sdei.c
> @@ -489,6 +489,68 @@ static unsigned long kvm_sdei_hypercall_info(struct kvm_vcpu *vcpu)
> return ret;
> }
>
> +static unsigned long kvm_sdei_hypercall_route(struct kvm_vcpu *vcpu)
> +{
> + 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);
> + unsigned long route_mode = smccc_get_arg2(vcpu);
> + unsigned long route_affinity = smccc_get_arg3(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)) {
> + ret = SDEI_INVALID_PARAMETERS;
> + goto out;
> + }
> +
> + if (!(route_mode == SDEI_EVENT_REGISTER_RM_ANY ||
> + route_mode == SDEI_EVENT_REGISTER_RM_PE)) {
> + ret = SDEI_INVALID_PARAMETERS;
> + goto out;
> + }
Some sanity checking on the affinity arg could be made as well according
to 5.1.2 affinity desc. The fn shall return INVALID_PARAMETER in case
of invalid affinity.
> +
> + /* Check if the KVM event has been registered */
> + spin_lock(&ksdei->lock);
> + kske = kvm_sdei_find_kvm_event(kvm, event_num);
> + if (!kske) {
> + ret = SDEI_INVALID_PARAMETERS;
> + goto unlock;
> + }
> +
> + /* Validate KVM event state */
> + kse = kske->kse;
> + if (kse->state.type != SDEI_EVENT_TYPE_SHARED) {
> + ret = SDEI_INVALID_PARAMETERS;
> + goto unlock;
> + }
> +
Event handler is in a state other than: handler-registered.
> + if (!kvm_sdei_is_registered(kske, index) ||
> + kvm_sdei_is_enabled(kske, index) ||
> + kske->state.refcount) {
I am not sure about the refcount role here. Does it make sure the state
is != handler-enabled and running or handler-unregister-pending?

I think we would gain in readibility if we had a helper to check whether
we are in those states?
> + ret = SDEI_DENIED;
> + goto unlock;
> + }
> +
> + /* Update state */
> + kske->state.route_mode = route_mode;
> + kske->state.route_affinity = route_affinity;
> +
> +unlock:
> + spin_unlock(&ksdei->lock);
> +out:
> + return ret;
> +}
> +
> int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
> {
> u32 func = smccc_get_function(vcpu);
> @@ -523,6 +585,8 @@ int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
> ret = kvm_sdei_hypercall_info(vcpu);
> break;
> case SDEI_1_0_FN_SDEI_EVENT_ROUTING_SET:
> + ret = kvm_sdei_hypercall_route(vcpu);
> + break;
> case SDEI_1_0_FN_SDEI_PE_MASK:
> case SDEI_1_0_FN_SDEI_PE_UNMASK:
> case SDEI_1_0_FN_SDEI_INTERRUPT_BIND:
>
Eric