Re: [PATCH v4 08/21] KVM: arm64: Support SDEI_EVENT_STATUS hypercall

Gavin Shan
2022-01-12T02:41:18Z

Hi Eric,

On 11/10/21 1:12 AM, Eric Auger wrote:
> On 8/15/21 2:13 AM, Gavin Shan wrote:
>> This supports SDEI_EVENT_STATUS hypercall. It's used by the guest
>> to retrieve a bitmap to indicate the SDEI event states, including
>> registration, enablement and delivery state.
>>
>> Signed-off-by: Gavin Shan <gshan@redhat.com>
>> ---
>> arch/arm64/kvm/sdei.c | 50 +++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 50 insertions(+)
>>
>> diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c
>> index a3ba69dc91cb..b95b8c4455e1 100644
>> --- a/arch/arm64/kvm/sdei.c
>> +++ b/arch/arm64/kvm/sdei.c
>> @@ -367,6 +367,54 @@ static unsigned long kvm_sdei_hypercall_unregister(struct kvm_vcpu *vcpu)
>> return ret;
>> }
>>
>> +static unsigned long kvm_sdei_hypercall_status(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);
>> + 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 we were to support bound events, I do not know if a given even num
> can disapper inbetween that check and the rest of the code, in which
> case a lock would be needed?

For the bound events, it's possbile. However, @ksdei->lock can be reused
in that cause. Anyway, it's something for future :)

>> +
>> + /*
>> + * Check if the KVM event exists. None of the flags
>> + * will be set if it doesn't exist.
>> + */
>> + spin_lock(&ksdei->lock);
>> + kske = kvm_sdei_find_kvm_event(kvm, event_num);
>> + if (!kske) {
>> + ret = 0;
>> + goto unlock;
>> + }
>> +
>> + index = (kse->state.type == SDEI_EVENT_TYPE_PRIVATE) ?
>> + vcpu->vcpu_idx : 0;
>> + if (kvm_sdei_is_registered(kske, index))
>> + ret |= (1UL << SDEI_EVENT_STATUS_REGISTERED);
>> + if (kvm_sdei_is_enabled(kske, index))
>> + ret |= (1UL << SDEI_EVENT_STATUS_ENABLED);
>> + if (kske->state.refcount)
>> + ret |= (1UL << SDEI_EVENT_STATUS_RUNNING);
>> +
>> +unlock:
>> + spin_unlock(&ksdei->lock);
>> +out:
>> + return ret;
>> +}
>> +
>> int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
>> {
>> u32 func = smccc_get_function(vcpu);
>> @@ -395,6 +443,8 @@ int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
>> ret = kvm_sdei_hypercall_unregister(vcpu);
>> break;
>> case SDEI_1_0_FN_SDEI_EVENT_STATUS:
>> + ret = kvm_sdei_hypercall_status(vcpu);
>> + break;
>> case SDEI_1_0_FN_SDEI_EVENT_GET_INFO:
>> case SDEI_1_0_FN_SDEI_EVENT_ROUTING_SET:
>> case SDEI_1_0_FN_SDEI_PE_MASK:
>>

Thanks,
Gavin