Re: [PATCH v4 09/21] KVM: arm64: Support SDEI_EVENT_GET_INFO hypercall

Gavin Shan
2022-01-12T02:47:24Z

Hi Eric,

On 11/10/21 1:19 AM, Eric Auger wrote:
> On 8/15/21 2:13 AM, Gavin Shan wrote:
>> This supports SDEI_EVENT_GET_INFO hypercall. It's used by the guest
>> to retrieve various information about the supported (exported) events,
>> including type, signaled, route mode and affinity for the shared
>> events.
>>
>> Signed-off-by: Gavin Shan <gshan@redhat.com>
>> ---
>> arch/arm64/kvm/sdei.c | 76 +++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 76 insertions(+)
>>
>> diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c
>> index b95b8c4455e1..5dfa74b093f1 100644
>> --- a/arch/arm64/kvm/sdei.c
>> +++ b/arch/arm64/kvm/sdei.c
>> @@ -415,6 +415,80 @@ static unsigned long kvm_sdei_hypercall_status(struct kvm_vcpu *vcpu)
>> return ret;
>> }
>>
>> +static unsigned long kvm_sdei_hypercall_info(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 event_info = smccc_get_arg2(vcpu);
>> + 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;
>> + }
>> +
>> + /*
>> + * Check if the KVM event exists. The event might have been
>> + * registered, we need fetch the information from the registered
> s/fetch/to fetch

Ack.

>> + * event in that case.
>> + */
>> + spin_lock(&ksdei->lock);
>> + kske = kvm_sdei_find_kvm_event(kvm, event_num);
>> + kse = kske ? kske->kse : NULL;
>> + if (!kse) {
>> + kse = kvm_sdei_find_event(kvm, event_num);
>> + if (!kse) {
>> + ret = SDEI_INVALID_PARAMETERS;
> this should have already be covered by !kvm_sdei_is_valid_event_num I
> think (although this latter only checks the since static event num with
> KVM owner mask)

Nope. Strictly speaking, kvm_sdei_find_event() covers the check carried
by !kvm_sdei_is_valid_event_num(). All the defined (exposed) events should
have virtual event number :)

>> + goto unlock;
>> + }
>> + }
>> +
>> + /* Retrieve the requested information */
>> + switch (event_info) {
>> + case SDEI_EVENT_INFO_EV_TYPE:
>> + ret = kse->state.type;
>> + break;
>> + case SDEI_EVENT_INFO_EV_SIGNALED:
>> + ret = kse->state.signaled;
>> + break;
>> + case SDEI_EVENT_INFO_EV_PRIORITY:
>> + ret = kse->state.priority;
>> + break;
>> + case SDEI_EVENT_INFO_EV_ROUTING_MODE:
>> + case SDEI_EVENT_INFO_EV_ROUTING_AFF:
>> + if (kse->state.type != SDEI_EVENT_TYPE_SHARED) {
>> + ret = SDEI_INVALID_PARAMETERS;
>> + break;
>> + }
>> +
>> + if (event_info == SDEI_EVENT_INFO_EV_ROUTING_MODE) {
>> + ret = kske ? kske->state.route_mode :
>> + SDEI_EVENT_REGISTER_RM_ANY;
> no, if event is not registered (!kske) DENIED should be returned

I don't think so. According to the specification, there is no DENIED
return value for STATUS hypercall. Either INVALID_PARAMETERS or NOT_SUPPORTED
should be returned from this hypercall :)

>> + } else {
> same here
>> + ret = kske ? kske->state.route_affinity : 0;
>> + }
>> +
>> + break;
>> + default:
>> + ret = SDEI_INVALID_PARAMETERS;
>> + }
>> +
>> +unlock:
>> + spin_unlock(&ksdei->lock);
>> +out:
>> + return ret;
>> +}
>> +
>> int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
>> {
>> u32 func = smccc_get_function(vcpu);
>> @@ -446,6 +520,8 @@ int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
>> ret = kvm_sdei_hypercall_status(vcpu);
>> break;
>> case SDEI_1_0_FN_SDEI_EVENT_GET_INFO:
>> + ret = kvm_sdei_hypercall_info(vcpu);
>> + break;
>> case SDEI_1_0_FN_SDEI_EVENT_ROUTING_SET:
>> case SDEI_1_0_FN_SDEI_PE_MASK:
>> case SDEI_1_0_FN_SDEI_PE_UNMASK:
>>

Thanks,
Gavin