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Subject: Re: [PATCH v4 09/21] KVM: arm64: Support SDEI_EVENT_GET_INFO
 hypercall
To:     Gavin Shan <gshan@redhat.com>, kvmarm@lists.cs.columbia.edu
Cc:     maz@kernel.org, linux-kernel@vger.kernel.org,
        Jonathan.Cameron@huawei.com, pbonzini@redhat.com, will@kernel.org
References: <20210815001352.81927-1-gshan@redhat.com>
 <20210815001352.81927-10-gshan@redhat.com>
From:   Eric Auger <eauger@redhat.com>
Message-ID: <03e9b1fb-af79-69bf-f242-00fef3b11a81@redhat.com>
Date:   Tue, 9 Nov 2021 18:19:58 +0100
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Hi Gavin,

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
> +	 * 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)
> +			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
> +		} 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:
> 
Eric