1 files changed, 68 insertions, 20 deletions

diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c
index 6ca0d7376a9f..a3f9c665bb5b 100644
--- a/arch/powerpc/kvm/book3s_xive.c
+++ b/arch/powerpc/kvm/book3s_xive.c
@@ -67,8 +67,14 @@ void kvmppc_xive_push_vcpu(struct kvm_vcpu *vcpu)
 	void __iomem *tima = local_paca->kvm_hstate.xive_tima_virt;
 	u64 pq;
 
-	if (!tima)
+	/*
+	 * Nothing to do if the platform doesn't have a XIVE
+	 * or this vCPU doesn't have its own XIVE context
+	 * (e.g. because it's not using an in-kernel interrupt controller).
+	 */
+	if (!tima || !vcpu->arch.xive_cam_word)
 		return;
+
 	eieio();
 	__raw_writeq(vcpu->arch.xive_saved_state.w01, tima + TM_QW1_OS);
 	__raw_writel(vcpu->arch.xive_cam_word, tima + TM_QW1_OS + TM_WORD2);
@@ -160,6 +166,9 @@ static irqreturn_t xive_esc_irq(int irq, void *data)
 	 */
 	vcpu->arch.xive_esc_on = false;
 
+	/* This orders xive_esc_on = false vs. subsequent stale_p = true */
+	smp_wmb();	/* goes with smp_mb() in cleanup_single_escalation */
+
 	return IRQ_HANDLED;
 }
 
@@ -1113,6 +1122,31 @@ void kvmppc_xive_disable_vcpu_interrupts(struct kvm_vcpu *vcpu)
 	vcpu->arch.xive_esc_raddr = 0;
 }
 
+/*
+ * In single escalation mode, the escalation interrupt is marked so
+ * that EOI doesn't re-enable it, but just sets the stale_p flag to
+ * indicate that the P bit has already been dealt with.  However, the
+ * assembly code that enters the guest sets PQ to 00 without clearing
+ * stale_p (because it has no easy way to address it).  Hence we have
+ * to adjust stale_p before shutting down the interrupt.
+ */
+void xive_cleanup_single_escalation(struct kvm_vcpu *vcpu,
+				    struct kvmppc_xive_vcpu *xc, int irq)
+{
+	struct irq_data *d = irq_get_irq_data(irq);
+	struct xive_irq_data *xd = irq_data_get_irq_handler_data(d);
+
+	/*
+	 * This slightly odd sequence gives the right result
+	 * (i.e. stale_p set if xive_esc_on is false) even if
+	 * we race with xive_esc_irq() and xive_irq_eoi().
+	 */
+	xd->stale_p = false;
+	smp_mb();		/* paired with smb_wmb in xive_esc_irq */
+	if (!vcpu->arch.xive_esc_on)
+		xd->stale_p = true;
+}
+
 void kvmppc_xive_cleanup_vcpu(struct kvm_vcpu *vcpu)
 {
 	struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
@@ -1134,20 +1168,28 @@ void kvmppc_xive_cleanup_vcpu(struct kvm_vcpu *vcpu)
 	/* Mask the VP IPI */
 	xive_vm_esb_load(&xc->vp_ipi_data, XIVE_ESB_SET_PQ_01);
 
-	/* Disable the VP */
-	xive_native_disable_vp(xc->vp_id);
-
-	/* Free the queues & associated interrupts */
+	/* Free escalations */
 	for (i = 0; i < KVMPPC_XIVE_Q_COUNT; i++) {
-		struct xive_q *q = &xc->queues[i];
-
-		/* Free the escalation irq */
 		if (xc->esc_virq[i]) {
+			if (xc->xive->single_escalation)
+				xive_cleanup_single_escalation(vcpu, xc,
+							xc->esc_virq[i]);
 			free_irq(xc->esc_virq[i], vcpu);
 			irq_dispose_mapping(xc->esc_virq[i]);
 			kfree(xc->esc_virq_names[i]);
 		}
-		/* Free the queue */
+	}
+
+	/* Disable the VP */
+	xive_native_disable_vp(xc->vp_id);
+
+	/* Clear the cam word so guest entry won't try to push context */
+	vcpu->arch.xive_cam_word = 0;
+
+	/* Free the queues */
+	for (i = 0; i < KVMPPC_XIVE_Q_COUNT; i++) {
+		struct xive_q *q = &xc->queues[i];
+
 		xive_native_disable_queue(xc->vp_id, q, i);
 		if (q->qpage) {
 			free_pages((unsigned long)q->qpage,
@@ -1175,6 +1217,7 @@ int kvmppc_xive_connect_vcpu(struct kvm_device *dev,
 	struct kvmppc_xive *xive = dev->private;
 	struct kvmppc_xive_vcpu *xc;
 	int i, r = -EBUSY;
+	u32 vp_id;
 
 	pr_devel("connect_vcpu(cpu=%d)\n", cpu);
 
@@ -1186,25 +1229,32 @@ int kvmppc_xive_connect_vcpu(struct kvm_device *dev,
 		return -EPERM;
 	if (vcpu->arch.irq_type != KVMPPC_IRQ_DEFAULT)
 		return -EBUSY;
-	if (kvmppc_xive_find_server(vcpu->kvm, cpu)) {
-		pr_devel("Duplicate !\n");
-		return -EEXIST;
-	}
 	if (cpu >= (KVM_MAX_VCPUS * vcpu->kvm->arch.emul_smt_mode)) {
 		pr_devel("Out of bounds !\n");
 		return -EINVAL;
 	}
-	xc = kzalloc(sizeof(*xc), GFP_KERNEL);
-	if (!xc)
-		return -ENOMEM;
 
 	/* We need to synchronize with queue provisioning */
 	mutex_lock(&xive->lock);
+
+	vp_id = kvmppc_xive_vp(xive, cpu);
+	if (kvmppc_xive_vp_in_use(xive->kvm, vp_id)) {
+		pr_devel("Duplicate !\n");
+		r = -EEXIST;
+		goto bail;
+	}
+
+	xc = kzalloc(sizeof(*xc), GFP_KERNEL);
+	if (!xc) {
+		r = -ENOMEM;
+		goto bail;
+	}
+
 	vcpu->arch.xive_vcpu = xc;
 	xc->xive = xive;
 	xc->vcpu = vcpu;
 	xc->server_num = cpu;
-	xc->vp_id = kvmppc_xive_vp(xive, cpu);
+	xc->vp_id = vp_id;
 	xc->mfrr = 0xff;
 	xc->valid = true;
 
@@ -1986,10 +2036,8 @@ static int kvmppc_xive_create(struct kvm_device *dev, u32 type)
 
 	xive->single_escalation = xive_native_has_single_escalation();
 
-	if (ret) {
-		kfree(xive);
+	if (ret)
 		return ret;
-	}
 
 	return 0;
 }