[PATCH v6 08/18] KVM: arm64: Support SDEI_EVENT_STATUS hypercall

[Gavin Shan <gshan@redhat.com>]

This supports SDEI_EVENT_STATUS hypercall. It's used by guest
to retrieve the status about the specified event. A bitmap is
returned to indicate the corresponding status: registration,
enablement and servicing state.

Signed-off-by: Gavin Shan <gshan@redhat.com>
---
 arch/arm64/kvm/sdei.c | 45 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c
index f774f2cf0ac7..b847c6028b74 100644
--- a/arch/arm64/kvm/sdei.c
+++ b/arch/arm64/kvm/sdei.c
@@ -247,6 +247,48 @@ static unsigned long hypercall_unregister(struct kvm_vcpu *vcpu)
 	return ret;
 }
 
+static unsigned long hypercall_status(struct kvm_vcpu *vcpu)
+{
+	struct kvm_sdei_vcpu *vsdei = vcpu->arch.sdei;
+	struct kvm_sdei_vcpu_context *context;
+	struct kvm_sdei_exposed_event *exposed_event;
+	struct kvm_sdei_event *event;
+	unsigned int num = smccc_get_arg(vcpu, 1);
+	unsigned long ret = 0;
+
+	if (!kvm_sdei_is_supported(num)) {
+		ret = SDEI_INVALID_PARAMETERS;
+		goto out;
+	}
+
+	spin_lock(&vsdei->lock);
+
+	/*
+	 * Check if the event exists. None of the flags will be set
+	 * if it doesn't exist.
+	 */
+	event = find_event(vcpu, num);
+	if (!event)
+		goto unlock;
+
+	if (kvm_sdei_is_registered(event))
+		ret |= (1UL << SDEI_EVENT_STATUS_REGISTERED);
+	if (kvm_sdei_is_enabled(event))
+		ret |= (1UL << SDEI_EVENT_STATUS_ENABLED);
+
+	exposed_event = event->exposed_event;
+	context = kvm_sdei_is_critical(exposed_event->priority) ?
+		  &vsdei->context[SDEI_EVENT_PRIORITY_CRITICAL] :
+		  &vsdei->context[SDEI_EVENT_PRIORITY_NORMAL];
+	if (context->event == event)
+		ret |= (1UL << SDEI_EVENT_STATUS_RUNNING);
+
+unlock:
+	spin_unlock(&vsdei->lock);
+out:
+	return ret;
+}
+
 int kvm_sdei_call(struct kvm_vcpu *vcpu)
 {
 	struct kvm_sdei_vcpu *vsdei = vcpu->arch.sdei;
@@ -283,6 +325,9 @@ int kvm_sdei_call(struct kvm_vcpu *vcpu)
 	case SDEI_1_0_FN_SDEI_EVENT_UNREGISTER:
 		ret = hypercall_unregister(vcpu);
 		break;
+	case SDEI_1_0_FN_SDEI_EVENT_STATUS:
+		ret = hypercall_status(vcpu);
+		break;
 	default:
 		ret = SDEI_NOT_SUPPORTED;
 	}
-- 
2.23.0