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

Gavin Shan
2022-01-12T02:29:30Z

Hi Eric,

On 11/10/21 12:02 AM, Eric Auger wrote:
> 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()

kvm_sdei_is_virtual() has been recommended by you when you reviewed the following
patch. I think kvm_sdei_is_virtual() is good enough :)

[PATCH v4 02/21] KVM: arm64: Add SDEI virtualization infrastructure

>> + 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?

Ok.

>> + 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?

Yep, It should be DENIED.

>> + goto unlock;
>> + }
>> +
>> + /* Check if it has been registered */
> isn't duplicate of /* Check if the KVM event exists */ ?

It's not duplicate check, but the comment here seems misleading. I will
correct this to:

/* Check if it has been defined or exposed */

>> + 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.

yep, it 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:
>>

Thanks,
Gavin