[PATCH v4 18/21] KVM: arm64: Support SDEI event injection

[Gavin Shan]

This supports SDEI event injection by implementing kvm_sdei_inject().
It's called by kernel directly or VMM through ioctl command to inject
SDEI event to the specific vCPU.

Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>
---
 arch/arm64/include/asm/kvm_sdei.h      |   2 +
 arch/arm64/include/uapi/asm/kvm_sdei.h |   1 +
 arch/arm64/kvm/sdei.c                  | 108 +++++++++++++++++++++++++
 3 files changed, 111 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_sdei.h b/arch/arm64/include/asm/kvm_sdei.h
index a997989bab77..51087fe971ba 100644
--- a/arch/arm64/include/asm/kvm_sdei.h
+++ b/arch/arm64/include/asm/kvm_sdei.h
@@ -124,6 +124,8 @@ void kvm_sdei_create_vcpu(struct kvm_vcpu *vcpu);
 int kvm_sdei_hypercall(struct kvm_vcpu *vcpu);
 int kvm_sdei_register_notifier(struct kvm *kvm, unsigned long num,
 			       kvm_sdei_notifier notifier);
+int kvm_sdei_inject(struct kvm_vcpu *vcpu,
+		    unsigned long num, bool immediate);
 void kvm_sdei_deliver(struct kvm_vcpu *vcpu);
 long kvm_sdei_vm_ioctl(struct kvm *kvm, unsigned long arg);
 long kvm_sdei_vcpu_ioctl(struct kvm_vcpu *vcpu, unsigned long arg);
diff --git a/arch/arm64/include/uapi/asm/kvm_sdei.h b/arch/arm64/include/uapi/asm/kvm_sdei.h
index b916c3435646..f7a6b2b22b50 100644
--- a/arch/arm64/include/uapi/asm/kvm_sdei.h
+++ b/arch/arm64/include/uapi/asm/kvm_sdei.h
@@ -67,6 +67,7 @@ struct kvm_sdei_vcpu_state {
 #define KVM_SDEI_CMD_SET_VEVENT			7
 #define KVM_SDEI_CMD_GET_VCPU_STATE		8
 #define KVM_SDEI_CMD_SET_VCPU_STATE		9
+#define KVM_SDEI_CMD_INJECT_EVENT		10
 
 struct kvm_sdei_cmd {
 	__u32						cmd;
diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c
index 79315b77f24b..7c2789cd1421 100644
--- a/arch/arm64/kvm/sdei.c
+++ b/arch/arm64/kvm/sdei.c
@@ -802,6 +802,111 @@ int kvm_sdei_register_notifier(struct kvm *kvm,
 	return ret;
 }
 
+int kvm_sdei_inject(struct kvm_vcpu *vcpu,
+		    unsigned long num,
+		    bool immediate)
+{
+	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;
+	struct kvm_sdei_vcpu_event *ksve = NULL;
+	int index, ret = 0;
+
+	/* Sanity check */
+	if (!(ksdei && vsdei)) {
+		ret = -EPERM;
+		goto out;
+	}
+
+	if (!kvm_sdei_is_valid_event_num(num)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* Check the kvm event */
+	spin_lock(&ksdei->lock);
+	kske = kvm_sdei_find_kvm_event(kvm, num);
+	if (!kske) {
+		ret = -ENOENT;
+		goto unlock_kvm;
+	}
+
+	kse = kske->kse;
+	index = (kse->state.type == SDEI_EVENT_TYPE_PRIVATE) ?
+		vcpu->vcpu_idx : 0;
+	if (!(kvm_sdei_is_registered(kske, index) &&
+	      kvm_sdei_is_enabled(kske, index))) {
+		ret = -EPERM;
+		goto unlock_kvm;
+	}
+
+	/* Check the vcpu state */
+	spin_lock(&vsdei->lock);
+	if (vsdei->state.masked) {
+		ret = -EPERM;
+		goto unlock_vcpu;
+	}
+
+	/* Check if the event can be delivered immediately */
+	if (immediate) {
+		if (kse->state.priority == SDEI_EVENT_PRIORITY_CRITICAL &&
+		    !list_empty(&vsdei->critical_events)) {
+			ret = -ENOSPC;
+			goto unlock_vcpu;
+		}
+
+		if (kse->state.priority == SDEI_EVENT_PRIORITY_NORMAL &&
+		    (!list_empty(&vsdei->critical_events) ||
+		     !list_empty(&vsdei->normal_events))) {
+			ret = -ENOSPC;
+			goto unlock_vcpu;
+		}
+	}
+
+	/* Check if the vcpu event exists */
+	ksve = kvm_sdei_find_vcpu_event(vcpu, num);
+	if (ksve) {
+		kske->state.refcount++;
+		ksve->state.refcount++;
+		kvm_make_request(KVM_REQ_SDEI, vcpu);
+		goto unlock_vcpu;
+	}
+
+	/* Allocate vcpu event */
+	ksve = kzalloc(sizeof(*ksve), GFP_KERNEL);
+	if (!ksve) {
+		ret = -ENOMEM;
+		goto unlock_vcpu;
+	}
+
+	/*
+	 * We should take lock to update KVM event state because its
+	 * reference count might be zero. In that case, the KVM event
+	 * could be destroyed.
+	 */
+	kske->state.refcount++;
+	ksve->state.num      = num;
+	ksve->state.refcount = 1;
+	ksve->kske           = kske;
+	ksve->vcpu           = vcpu;
+
+	if (kse->state.priority == SDEI_EVENT_PRIORITY_CRITICAL)
+		list_add_tail(&ksve->link, &vsdei->critical_events);
+	else
+		list_add_tail(&ksve->link, &vsdei->normal_events);
+
+	kvm_make_request(KVM_REQ_SDEI, vcpu);
+
+unlock_vcpu:
+	spin_unlock(&vsdei->lock);
+unlock_kvm:
+	spin_unlock(&ksdei->lock);
+out:
+	return ret;
+}
+
 void kvm_sdei_deliver(struct kvm_vcpu *vcpu)
 {
 	struct kvm *kvm = vcpu->kvm;
@@ -1317,6 +1422,9 @@ long kvm_sdei_vcpu_ioctl(struct kvm_vcpu *vcpu, unsigned long arg)
 	case KVM_SDEI_CMD_SET_VCPU_STATE:
 		ret = kvm_sdei_set_vcpu_state(vcpu, &cmd->ksv_state);
 		break;
+	case KVM_SDEI_CMD_INJECT_EVENT:
+		ret = kvm_sdei_inject(vcpu, cmd->num, false);
+		break;
 	default:
 		ret = -EINVAL;
 	}
-- 
2.23.0