[PATCH 08/18] arm64/kvm: Support SDEI_1_0_FN_SDEI_EVENT_UNREGISTER hypercall

From: Gavin Shan <gshan@redhat.com>
To: kvmarm@lists.cs.columbia.edu
Cc: maz@kernel.org, shan.gavin@gmail.com, pbonzini@redhat.com
Subject: [PATCH 08/18] arm64/kvm: Support SDEI_1_0_FN_SDEI_EVENT_UNREGISTER hypercall
Date: Mon, 17 Aug 2020 20:05:21 +1000	[thread overview]
Message-ID: <20200817100531.83045-9-gshan@redhat.com> (raw)
In-Reply-To: <20200817100531.83045-1-gshan@redhat.com>

This supports SDEI_1_0_FN_SDEI_EVENT_UNREGISTER hypercall by adding
function kvm_sdei_hypercall_unregister(). For event owned by KVM
itself, the register status is updated accordingly and the event is
released if the event isn't needed. For passthrou event, the event
is also unregistered from the underly firmware in that case.

Signed-off-by: Gavin Shan <gshan@redhat.com>
---
 arch/arm64/kvm/sdei.c | 73 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c
index 320b79528211..63d621dc9711 100644
--- a/arch/arm64/kvm/sdei.c
+++ b/arch/arm64/kvm/sdei.c
@@ -343,6 +343,77 @@ static unsigned long kvm_sdei_hypercall_enable(struct kvm_vcpu *vcpu,
 	return ret;
 }
 
+static unsigned long kvm_sdei_hypercall_unregister(struct kvm_vcpu *vcpu)
+{
+	struct kvm *kvm = vcpu->kvm;
+	struct kvm_sdei_event *event = NULL;
+	struct kvm_sdei_kvm_event *kevent = NULL;
+	unsigned long event_num = smccc_get_arg1(vcpu);
+	unsigned long event_type;
+	int index = 0;
+	unsigned long ret = SDEI_SUCCESS;
+
+	/* Validate event number */
+	if (!kvm_sdei_num_is_valid(event_num)) {
+		ret = SDEI_INVALID_PARAMETERS;
+		goto out;
+	}
+
+	if (!(kvm_sdei_data && kvm_sdei_data->supported) &&
+	    kvm_sdei_num_is_virt(event_num)) {
+		ret = SDEI_INVALID_PARAMETERS;
+		goto out;
+	}
+
+	/* Find the event */
+	spin_lock(&kvm_sdei_lock);
+	event = kvm_sdei_find_event(kvm, event_num, &kevent, NULL, NULL);
+	if (!kevent) {
+		ret = SDEI_INVALID_PARAMETERS;
+		goto unlock;
+	}
+
+	/* Sanity check */
+	spin_lock(&event->lock);
+	if (kevent->users) {
+		ret = SDEI_PENDING;
+		goto unlock_event;
+	}
+
+	event_type = event->priv ? event->priv->type : event->event->type;
+	index = (event_type == SDEI_EVENT_TYPE_PRIVATE) ? vcpu->vcpu_idx : 0;
+	if (!test_bit(index, kevent->registered)) {
+		ret = SDEI_DENIED;
+		goto unlock_event;
+	}
+
+	/* Update status and destroy it if needed */
+	clear_bit(index, kevent->registered);
+	clear_bit(index, kevent->enabled);
+	if (!bitmap_empty(kevent->registered, KVM_MAX_VCPUS))
+		goto unlock_event;
+
+	rb_erase(&kevent->node, &event->root);
+	kfree(kevent);
+	event->count--;
+	if (event->count)
+		goto unlock_event;
+
+	spin_unlock(&event->lock);
+	list_del(&event->link);
+	if (event->event)
+		kvm_sdei_unregister_event(event->event);
+	kfree(event);
+	goto unlock;
+
+unlock_event:
+	spin_unlock(&event->lock);
+unlock:
+	spin_unlock(&kvm_sdei_lock);
+out:
+	return ret;
+}
+
 static unsigned long kvm_sdei_reset(struct kvm *kvm, unsigned int types)
 {
 	struct kvm_sdei_event *e, *event = NULL;
@@ -429,6 +500,8 @@ int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
 	case SDEI_1_0_FN_SDEI_EVENT_COMPLETE:
 	case SDEI_1_0_FN_SDEI_EVENT_COMPLETE_AND_RESUME:
 	case SDEI_1_0_FN_SDEI_EVENT_UNREGISTER:
+		ret = kvm_sdei_hypercall_unregister(vcpu);
+		break;
 	case SDEI_1_0_FN_SDEI_EVENT_STATUS:
 	case SDEI_1_0_FN_SDEI_EVENT_GET_INFO:
 	case SDEI_1_0_FN_SDEI_EVENT_ROUTING_SET:
-- 
2.23.0

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