1 files changed, 341 insertions, 184 deletions

diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index 40c3d7cf163f..c76e753b3cec 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -23,11 +23,12 @@
 #include "vfio_pci_priv.h"
 
 struct vfio_pci_irq_ctx {
-	struct eventfd_ctx	*trigger;
-	struct virqfd		*unmask;
-	struct virqfd		*mask;
-	char			*name;
-	bool			masked;
+	struct vfio_pci_core_device	*vdev;
+	struct eventfd_ctx		*trigger;
+	struct virqfd			*unmask;
+	struct virqfd			*mask;
+	char				*name;
+	bool				masked;
 	struct irq_bypass_producer	producer;
 };
 
@@ -48,24 +49,65 @@ static bool is_irq_none(struct vfio_pci_core_device *vdev)
 		 vdev->irq_type == VFIO_PCI_MSIX_IRQ_INDEX);
 }
 
+static
+struct vfio_pci_irq_ctx *vfio_irq_ctx_get(struct vfio_pci_core_device *vdev,
+					  unsigned long index)
+{
+	return xa_load(&vdev->ctx, index);
+}
+
+static void vfio_irq_ctx_free(struct vfio_pci_core_device *vdev,
+			      struct vfio_pci_irq_ctx *ctx, unsigned long index)
+{
+	xa_erase(&vdev->ctx, index);
+	kfree(ctx);
+}
+
+static struct vfio_pci_irq_ctx *
+vfio_irq_ctx_alloc(struct vfio_pci_core_device *vdev, unsigned long index)
+{
+	struct vfio_pci_irq_ctx *ctx;
+	int ret;
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
+	if (!ctx)
+		return NULL;
+
+	ret = xa_insert(&vdev->ctx, index, ctx, GFP_KERNEL_ACCOUNT);
+	if (ret) {
+		kfree(ctx);
+		return NULL;
+	}
+
+	return ctx;
+}
+
 /*
  * INTx
  */
-static void vfio_send_intx_eventfd(void *opaque, void *unused)
+static void vfio_send_intx_eventfd(void *opaque, void *data)
 {
 	struct vfio_pci_core_device *vdev = opaque;
 
-	if (likely(is_intx(vdev) && !vdev->virq_disabled))
-		eventfd_signal(vdev->ctx[0].trigger, 1);
+	if (likely(is_intx(vdev) && !vdev->virq_disabled)) {
+		struct vfio_pci_irq_ctx *ctx = data;
+		struct eventfd_ctx *trigger = READ_ONCE(ctx->trigger);
+
+		if (likely(trigger))
+			eventfd_signal(trigger);
+	}
 }
 
 /* Returns true if the INTx vfio_pci_irq_ctx.masked value is changed. */
-bool vfio_pci_intx_mask(struct vfio_pci_core_device *vdev)
+static bool __vfio_pci_intx_mask(struct vfio_pci_core_device *vdev)
 {
 	struct pci_dev *pdev = vdev->pdev;
+	struct vfio_pci_irq_ctx *ctx;
 	unsigned long flags;
 	bool masked_changed = false;
 
+	lockdep_assert_held(&vdev->igate);
+
 	spin_lock_irqsave(&vdev->irqlock, flags);
 
 	/*
@@ -77,7 +119,14 @@ bool vfio_pci_intx_mask(struct vfio_pci_core_device *vdev)
 	if (unlikely(!is_intx(vdev))) {
 		if (vdev->pci_2_3)
 			pci_intx(pdev, 0);
-	} else if (!vdev->ctx[0].masked) {
+		goto out_unlock;
+	}
+
+	ctx = vfio_irq_ctx_get(vdev, 0);
+	if (WARN_ON_ONCE(!ctx))
+		goto out_unlock;
+
+	if (!ctx->masked) {
 		/*
 		 * Can't use check_and_mask here because we always want to
 		 * mask, not just when something is pending.
@@ -87,24 +136,37 @@ bool vfio_pci_intx_mask(struct vfio_pci_core_device *vdev)
 		else
 			disable_irq_nosync(pdev->irq);
 
-		vdev->ctx[0].masked = true;
+		ctx->masked = true;
 		masked_changed = true;
 	}
 
+out_unlock:
 	spin_unlock_irqrestore(&vdev->irqlock, flags);
 	return masked_changed;
 }
 
+bool vfio_pci_intx_mask(struct vfio_pci_core_device *vdev)
+{
+	bool mask_changed;
+
+	mutex_lock(&vdev->igate);
+	mask_changed = __vfio_pci_intx_mask(vdev);
+	mutex_unlock(&vdev->igate);
+
+	return mask_changed;
+}
+
 /*
  * If this is triggered by an eventfd, we can't call eventfd_signal
  * or else we'll deadlock on the eventfd wait queue.  Return >0 when
  * a signal is necessary, which can then be handled via a work queue
  * or directly depending on the caller.
  */
-static int vfio_pci_intx_unmask_handler(void *opaque, void *unused)
+static int vfio_pci_intx_unmask_handler(void *opaque, void *data)
 {
 	struct vfio_pci_core_device *vdev = opaque;
 	struct pci_dev *pdev = vdev->pdev;
+	struct vfio_pci_irq_ctx *ctx = data;
 	unsigned long flags;
 	int ret = 0;
 
@@ -117,7 +179,10 @@ static int vfio_pci_intx_unmask_handler(void *opaque, void *unused)
 	if (unlikely(!is_intx(vdev))) {
 		if (vdev->pci_2_3)
 			pci_intx(pdev, 1);
-	} else if (vdev->ctx[0].masked && !vdev->virq_disabled) {
+		goto out_unlock;
+	}
+
+	if (ctx->masked && !vdev->virq_disabled) {
 		/*
 		 * A pending interrupt here would immediately trigger,
 		 * but we can avoid that overhead by just re-sending
@@ -129,23 +194,36 @@ static int vfio_pci_intx_unmask_handler(void *opaque, void *unused)
 		} else
 			enable_irq(pdev->irq);
 
-		vdev->ctx[0].masked = (ret > 0);
+		ctx->masked = (ret > 0);
 	}
 
+out_unlock:
 	spin_unlock_irqrestore(&vdev->irqlock, flags);
 
 	return ret;
 }
 
+static void __vfio_pci_intx_unmask(struct vfio_pci_core_device *vdev)
+{
+	struct vfio_pci_irq_ctx *ctx = vfio_irq_ctx_get(vdev, 0);
+
+	lockdep_assert_held(&vdev->igate);
+
+	if (vfio_pci_intx_unmask_handler(vdev, ctx) > 0)
+		vfio_send_intx_eventfd(vdev, ctx);
+}
+
 void vfio_pci_intx_unmask(struct vfio_pci_core_device *vdev)
 {
-	if (vfio_pci_intx_unmask_handler(vdev, NULL) > 0)
-		vfio_send_intx_eventfd(vdev, NULL);
+	mutex_lock(&vdev->igate);
+	__vfio_pci_intx_unmask(vdev);
+	mutex_unlock(&vdev->igate);
 }
 
 static irqreturn_t vfio_intx_handler(int irq, void *dev_id)
 {
-	struct vfio_pci_core_device *vdev = dev_id;
+	struct vfio_pci_irq_ctx *ctx = dev_id;
+	struct vfio_pci_core_device *vdev = ctx->vdev;
 	unsigned long flags;
 	int ret = IRQ_NONE;
 
@@ -153,114 +231,140 @@ static irqreturn_t vfio_intx_handler(int irq, void *dev_id)
 
 	if (!vdev->pci_2_3) {
 		disable_irq_nosync(vdev->pdev->irq);
-		vdev->ctx[0].masked = true;
+		ctx->masked = true;
 		ret = IRQ_HANDLED;
-	} else if (!vdev->ctx[0].masked &&  /* may be shared */
+	} else if (!ctx->masked &&  /* may be shared */
 		   pci_check_and_mask_intx(vdev->pdev)) {
-		vdev->ctx[0].masked = true;
+		ctx->masked = true;
 		ret = IRQ_HANDLED;
 	}
 
 	spin_unlock_irqrestore(&vdev->irqlock, flags);
 
 	if (ret == IRQ_HANDLED)
-		vfio_send_intx_eventfd(vdev, NULL);
+		vfio_send_intx_eventfd(vdev, ctx);
 
 	return ret;
 }
 
-static int vfio_intx_enable(struct vfio_pci_core_device *vdev)
+static int vfio_intx_enable(struct vfio_pci_core_device *vdev,
+			    struct eventfd_ctx *trigger)
 {
+	struct pci_dev *pdev = vdev->pdev;
+	struct vfio_pci_irq_ctx *ctx;
+	unsigned long irqflags;
+	char *name;
+	int ret;
+
 	if (!is_irq_none(vdev))
 		return -EINVAL;
 
-	if (!vdev->pdev->irq)
+	if (!pdev->irq || pdev->irq == IRQ_NOTCONNECTED)
 		return -ENODEV;
 
-	vdev->ctx = kzalloc(sizeof(struct vfio_pci_irq_ctx), GFP_KERNEL);
-	if (!vdev->ctx)
+	name = kasprintf(GFP_KERNEL_ACCOUNT, "vfio-intx(%s)", pci_name(pdev));
+	if (!name)
+		return -ENOMEM;
+
+	ctx = vfio_irq_ctx_alloc(vdev, 0);
+	if (!ctx) {
+		kfree(name);
 		return -ENOMEM;
+	}
 
-	vdev->num_ctx = 1;
+	ctx->name = name;
+	ctx->trigger = trigger;
+	ctx->vdev = vdev;
 
 	/*
-	 * If the virtual interrupt is masked, restore it.  Devices
-	 * supporting DisINTx can be masked at the hardware level
-	 * here, non-PCI-2.3 devices will have to wait until the
-	 * interrupt is enabled.
+	 * Fill the initial masked state based on virq_disabled.  After
+	 * enable, changing the DisINTx bit in vconfig directly changes INTx
+	 * masking.  igate prevents races during setup, once running masked
+	 * is protected via irqlock.
+	 *
+	 * Devices supporting DisINTx also reflect the current mask state in
+	 * the physical DisINTx bit, which is not affected during IRQ setup.
+	 *
+	 * Devices without DisINTx support require an exclusive interrupt.
+	 * IRQ masking is performed at the IRQ chip.  Again, igate protects
+	 * against races during setup and IRQ handlers and irqfds are not
+	 * yet active, therefore masked is stable and can be used to
+	 * conditionally auto-enable the IRQ.
+	 *
+	 * irq_type must be stable while the IRQ handler is registered,
+	 * therefore it must be set before request_irq().
 	 */
-	vdev->ctx[0].masked = vdev->virq_disabled;
-	if (vdev->pci_2_3)
-		pci_intx(vdev->pdev, !vdev->ctx[0].masked);
+	ctx->masked = vdev->virq_disabled;
+	if (vdev->pci_2_3) {
+		pci_intx(pdev, !ctx->masked);
+		irqflags = IRQF_SHARED;
+	} else {
+		irqflags = ctx->masked ? IRQF_NO_AUTOEN : 0;
+	}
 
 	vdev->irq_type = VFIO_PCI_INTX_IRQ_INDEX;
 
+	if (!vdev->pci_2_3)
+		irq_set_status_flags(pdev->irq, IRQ_DISABLE_UNLAZY);
+
+	ret = request_irq(pdev->irq, vfio_intx_handler,
+			  irqflags, ctx->name, ctx);
+	if (ret) {
+		if (!vdev->pci_2_3)
+			irq_clear_status_flags(pdev->irq, IRQ_DISABLE_UNLAZY);
+		vdev->irq_type = VFIO_PCI_NUM_IRQS;
+		kfree(name);
+		vfio_irq_ctx_free(vdev, ctx, 0);
+		return ret;
+	}
+
 	return 0;
 }
 
-static int vfio_intx_set_signal(struct vfio_pci_core_device *vdev, int fd)
+static int vfio_intx_set_signal(struct vfio_pci_core_device *vdev,
+				struct eventfd_ctx *trigger)
 {
 	struct pci_dev *pdev = vdev->pdev;
-	unsigned long irqflags = IRQF_SHARED;
-	struct eventfd_ctx *trigger;
-	unsigned long flags;
-	int ret;
-
-	if (vdev->ctx[0].trigger) {
-		free_irq(pdev->irq, vdev);
-		kfree(vdev->ctx[0].name);
-		eventfd_ctx_put(vdev->ctx[0].trigger);
-		vdev->ctx[0].trigger = NULL;
-	}
-
-	if (fd < 0) /* Disable only */
-		return 0;
+	struct vfio_pci_irq_ctx *ctx;
+	struct eventfd_ctx *old;
 
-	vdev->ctx[0].name = kasprintf(GFP_KERNEL, "vfio-intx(%s)",
-				      pci_name(pdev));
-	if (!vdev->ctx[0].name)
-		return -ENOMEM;
-
-	trigger = eventfd_ctx_fdget(fd);
-	if (IS_ERR(trigger)) {
-		kfree(vdev->ctx[0].name);
-		return PTR_ERR(trigger);
-	}
+	ctx = vfio_irq_ctx_get(vdev, 0);
+	if (WARN_ON_ONCE(!ctx))
+		return -EINVAL;
 
-	vdev->ctx[0].trigger = trigger;
+	old = ctx->trigger;
 
-	if (!vdev->pci_2_3)
-		irqflags = 0;
+	WRITE_ONCE(ctx->trigger, trigger);
 
-	ret = request_irq(pdev->irq, vfio_intx_handler,
-			  irqflags, vdev->ctx[0].name, vdev);
-	if (ret) {
-		vdev->ctx[0].trigger = NULL;
-		kfree(vdev->ctx[0].name);
-		eventfd_ctx_put(trigger);
-		return ret;
+	/* Releasing an old ctx requires synchronizing in-flight users */
+	if (old) {
+		synchronize_irq(pdev->irq);
+		vfio_virqfd_flush_thread(&ctx->unmask);
+		eventfd_ctx_put(old);
 	}
 
-	/*
-	 * INTx disable will stick across the new irq setup,
-	 * disable_irq won't.
-	 */
-	spin_lock_irqsave(&vdev->irqlock, flags);
-	if (!vdev->pci_2_3 && vdev->ctx[0].masked)
-		disable_irq_nosync(pdev->irq);
-	spin_unlock_irqrestore(&vdev->irqlock, flags);
-
 	return 0;
 }
 
 static void vfio_intx_disable(struct vfio_pci_core_device *vdev)
 {
-	vfio_virqfd_disable(&vdev->ctx[0].unmask);
-	vfio_virqfd_disable(&vdev->ctx[0].mask);
-	vfio_intx_set_signal(vdev, -1);
+	struct pci_dev *pdev = vdev->pdev;
+	struct vfio_pci_irq_ctx *ctx;
+
+	ctx = vfio_irq_ctx_get(vdev, 0);
+	WARN_ON_ONCE(!ctx);
+	if (ctx) {
+		vfio_virqfd_disable(&ctx->unmask);
+		vfio_virqfd_disable(&ctx->mask);
+		free_irq(pdev->irq, ctx);
+		if (!vdev->pci_2_3)
+			irq_clear_status_flags(pdev->irq, IRQ_DISABLE_UNLAZY);
+		if (ctx->trigger)
+			eventfd_ctx_put(ctx->trigger);
+		kfree(ctx->name);
+		vfio_irq_ctx_free(vdev, ctx, 0);
+	}
 	vdev->irq_type = VFIO_PCI_NUM_IRQS;
-	vdev->num_ctx = 0;
-	kfree(vdev->ctx);
 }
 
 /*
@@ -270,7 +374,7 @@ static irqreturn_t vfio_msihandler(int irq, void *arg)
 {
 	struct eventfd_ctx *trigger = arg;
 
-	eventfd_signal(trigger, 1);
+	eventfd_signal(trigger);
 	return IRQ_HANDLED;
 }
 
@@ -284,10 +388,6 @@ static int vfio_msi_enable(struct vfio_pci_core_device *vdev, int nvec, bool msi
 	if (!is_irq_none(vdev))
 		return -EINVAL;
 
-	vdev->ctx = kcalloc(nvec, sizeof(struct vfio_pci_irq_ctx), GFP_KERNEL);
-	if (!vdev->ctx)
-		return -ENOMEM;
-
 	/* return the number of supported vectors if we can't get all: */
 	cmd = vfio_pci_memory_lock_and_enable(vdev);
 	ret = pci_alloc_irq_vectors(pdev, 1, nvec, flag);
@@ -295,12 +395,10 @@ static int vfio_msi_enable(struct vfio_pci_core_device *vdev, int nvec, bool msi
 		if (ret > 0)
 			pci_free_irq_vectors(pdev);
 		vfio_pci_memory_unlock_and_restore(vdev, cmd);
-		kfree(vdev->ctx);
 		return ret;
 	}
 	vfio_pci_memory_unlock_and_restore(vdev, cmd);
 
-	vdev->num_ctx = nvec;
 	vdev->irq_type = msix ? VFIO_PCI_MSIX_IRQ_INDEX :
 				VFIO_PCI_MSI_IRQ_INDEX;
 
@@ -315,52 +413,91 @@ static int vfio_msi_enable(struct vfio_pci_core_device *vdev, int nvec, bool msi
 	return 0;
 }
 
-static int vfio_msi_set_vector_signal(struct vfio_pci_core_device *vdev,
-				      int vector, int fd, bool msix)
+/*
+ * vfio_msi_alloc_irq() returns the Linux IRQ number of an MSI or MSI-X device
+ * interrupt vector. If a Linux IRQ number is not available then a new
+ * interrupt is allocated if dynamic MSI-X is supported.
+ *
+ * Where is vfio_msi_free_irq()? Allocated interrupts are maintained,
+ * essentially forming a cache that subsequent allocations can draw from.
+ * Interrupts are freed using pci_free_irq_vectors() when MSI/MSI-X is
+ * disabled.
+ */
+static int vfio_msi_alloc_irq(struct vfio_pci_core_device *vdev,
+			      unsigned int vector, bool msix)
 {
 	struct pci_dev *pdev = vdev->pdev;
-	struct eventfd_ctx *trigger;
-	int irq, ret;
+	struct msi_map map;
+	int irq;
 	u16 cmd;
 
-	if (vector < 0 || vector >= vdev->num_ctx)
+	irq = pci_irq_vector(pdev, vector);
+	if (WARN_ON_ONCE(irq == 0))
 		return -EINVAL;
+	if (irq > 0 || !msix || !vdev->has_dyn_msix)
+		return irq;
 
-	irq = pci_irq_vector(pdev, vector);
+	cmd = vfio_pci_memory_lock_and_enable(vdev);
+	map = pci_msix_alloc_irq_at(pdev, vector, NULL);
+	vfio_pci_memory_unlock_and_restore(vdev, cmd);
+
+	return map.index < 0 ? map.index : map.virq;
+}
+
+static int vfio_msi_set_vector_signal(struct vfio_pci_core_device *vdev,
+				      unsigned int vector, int fd, bool msix)
+{
+	struct pci_dev *pdev = vdev->pdev;
+	struct vfio_pci_irq_ctx *ctx;
+	struct eventfd_ctx *trigger;
+	int irq = -EINVAL, ret;
+	u16 cmd;
 
-	if (vdev->ctx[vector].trigger) {
-		irq_bypass_unregister_producer(&vdev->ctx[vector].producer);
+	ctx = vfio_irq_ctx_get(vdev, vector);
 
+	if (ctx) {
+		irq_bypass_unregister_producer(&ctx->producer);
+		irq = pci_irq_vector(pdev, vector);
 		cmd = vfio_pci_memory_lock_and_enable(vdev);
-		free_irq(irq, vdev->ctx[vector].trigger);
+		free_irq(irq, ctx->trigger);
 		vfio_pci_memory_unlock_and_restore(vdev, cmd);
-
-		kfree(vdev->ctx[vector].name);
-		eventfd_ctx_put(vdev->ctx[vector].trigger);
-		vdev->ctx[vector].trigger = NULL;
+		/* Interrupt stays allocated, will be freed at MSI-X disable. */
+		kfree(ctx->name);
+		eventfd_ctx_put(ctx->trigger);
+		vfio_irq_ctx_free(vdev, ctx, vector);
 	}
 
 	if (fd < 0)
 		return 0;
 
-	vdev->ctx[vector].name = kasprintf(GFP_KERNEL, "vfio-msi%s[%d](%s)",
-					   msix ? "x" : "", vector,
-					   pci_name(pdev));
-	if (!vdev->ctx[vector].name)
+	if (irq == -EINVAL) {
+		/* Interrupt stays allocated, will be freed at MSI-X disable. */
+		irq = vfio_msi_alloc_irq(vdev, vector, msix);
+		if (irq < 0)
+			return irq;
+	}
+
+	ctx = vfio_irq_ctx_alloc(vdev, vector);
+	if (!ctx)
 		return -ENOMEM;
 
+	ctx->name = kasprintf(GFP_KERNEL_ACCOUNT, "vfio-msi%s[%d](%s)",
+			      msix ? "x" : "", vector, pci_name(pdev));
+	if (!ctx->name) {
+		ret = -ENOMEM;
+		goto out_free_ctx;
+	}
+
 	trigger = eventfd_ctx_fdget(fd);
 	if (IS_ERR(trigger)) {
-		kfree(vdev->ctx[vector].name);
-		return PTR_ERR(trigger);
+		ret = PTR_ERR(trigger);
+		goto out_free_name;
 	}
 
 	/*
-	 * The MSIx vector table resides in device memory which may be cleared
-	 * via backdoor resets. We don't allow direct access to the vector
-	 * table so even if a userspace driver attempts to save/restore around
-	 * such a reset it would be unsuccessful. To avoid this, restore the
-	 * cached value of the message prior to enabling.
+	 * If the vector was previously allocated, refresh the on-device
+	 * message data before enabling in case it had been cleared or
+	 * corrupted (e.g. due to backdoor resets) since writing.
 	 */
 	cmd = vfio_pci_memory_lock_and_enable(vdev);
 	if (msix) {
@@ -370,37 +507,35 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_core_device *vdev,
 		pci_write_msi_msg(irq, &msg);
 	}
 
-	ret = request_irq(irq, vfio_msihandler, 0,
-			  vdev->ctx[vector].name, trigger);
+	ret = request_irq(irq, vfio_msihandler, 0, ctx->name, trigger);
 	vfio_pci_memory_unlock_and_restore(vdev, cmd);
-	if (ret) {
-		kfree(vdev->ctx[vector].name);
-		eventfd_ctx_put(trigger);
-		return ret;
-	}
+	if (ret)
+		goto out_put_eventfd_ctx;
 
-	vdev->ctx[vector].producer.token = trigger;
-	vdev->ctx[vector].producer.irq = irq;
-	ret = irq_bypass_register_producer(&vdev->ctx[vector].producer);
+	ret = irq_bypass_register_producer(&ctx->producer, trigger, irq);
 	if (unlikely(ret)) {
 		dev_info(&pdev->dev,
-		"irq bypass producer (token %p) registration fails: %d\n",
-		vdev->ctx[vector].producer.token, ret);
-
-		vdev->ctx[vector].producer.token = NULL;
+		"irq bypass producer (eventfd %p) registration fails: %d\n",
+		trigger, ret);
 	}
-	vdev->ctx[vector].trigger = trigger;
+	ctx->trigger = trigger;
 
 	return 0;
+
+out_put_eventfd_ctx:
+	eventfd_ctx_put(trigger);
+out_free_name:
+	kfree(ctx->name);
+out_free_ctx:
+	vfio_irq_ctx_free(vdev, ctx, vector);
+	return ret;
 }
 
 static int vfio_msi_set_block(struct vfio_pci_core_device *vdev, unsigned start,
 			      unsigned count, int32_t *fds, bool msix)
 {
-	int i, j, ret = 0;
-
-	if (start >= vdev->num_ctx || start + count > vdev->num_ctx)
-		return -EINVAL;
+	unsigned int i, j;
+	int ret = 0;
 
 	for (i = 0, j = start; i < count && !ret; i++, j++) {
 		int fd = fds ? fds[i] : -1;
@@ -408,8 +543,8 @@ static int vfio_msi_set_block(struct vfio_pci_core_device *vdev, unsigned start,
 	}
 
 	if (ret) {
-		for (--j; j >= (int)start; j--)
-			vfio_msi_set_vector_signal(vdev, j, -1, msix);
+		for (i = start; i < j; i++)
+			vfio_msi_set_vector_signal(vdev, i, -1, msix);
 	}
 
 	return ret;
@@ -418,16 +553,16 @@ static int vfio_msi_set_block(struct vfio_pci_core_device *vdev, unsigned start,
 static void vfio_msi_disable(struct vfio_pci_core_device *vdev, bool msix)
 {
 	struct pci_dev *pdev = vdev->pdev;
-	int i;
+	struct vfio_pci_irq_ctx *ctx;
+	unsigned long i;
 	u16 cmd;
 
-	for (i = 0; i < vdev->num_ctx; i++) {
-		vfio_virqfd_disable(&vdev->ctx[i].unmask);
-		vfio_virqfd_disable(&vdev->ctx[i].mask);
+	xa_for_each(&vdev->ctx, i, ctx) {
+		vfio_virqfd_disable(&ctx->unmask);
+		vfio_virqfd_disable(&ctx->mask);
+		vfio_msi_set_vector_signal(vdev, i, -1, msix);
 	}
 
-	vfio_msi_set_block(vdev, 0, vdev->num_ctx, NULL, msix);
-
 	cmd = vfio_pci_memory_lock_and_enable(vdev);
 	pci_free_irq_vectors(pdev);
 	vfio_pci_memory_unlock_and_restore(vdev, cmd);
@@ -440,8 +575,6 @@ static void vfio_msi_disable(struct vfio_pci_core_device *vdev, bool msix)
 		pci_intx(pdev, 0);
 
 	vdev->irq_type = VFIO_PCI_NUM_IRQS;
-	vdev->num_ctx = 0;
-	kfree(vdev->ctx);
 }
 
 /*
@@ -455,20 +588,24 @@ static int vfio_pci_set_intx_unmask(struct vfio_pci_core_device *vdev,
 		return -EINVAL;
 
 	if (flags & VFIO_IRQ_SET_DATA_NONE) {
-		vfio_pci_intx_unmask(vdev);
+		__vfio_pci_intx_unmask(vdev);
 	} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
 		uint8_t unmask = *(uint8_t *)data;
 		if (unmask)
-			vfio_pci_intx_unmask(vdev);
+			__vfio_pci_intx_unmask(vdev);
 	} else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
+		struct vfio_pci_irq_ctx *ctx = vfio_irq_ctx_get(vdev, 0);
 		int32_t fd = *(int32_t *)data;
+
+		if (WARN_ON_ONCE(!ctx))
+			return -EINVAL;
 		if (fd >= 0)
 			return vfio_virqfd_enable((void *) vdev,
 						  vfio_pci_intx_unmask_handler,
-						  vfio_send_intx_eventfd, NULL,
-						  &vdev->ctx[0].unmask, fd);
+						  vfio_send_intx_eventfd, ctx,
+						  &ctx->unmask, fd);
 
-		vfio_virqfd_disable(&vdev->ctx[0].unmask);
+		vfio_virqfd_disable(&ctx->unmask);
 	}
 
 	return 0;
@@ -482,11 +619,11 @@ static int vfio_pci_set_intx_mask(struct vfio_pci_core_device *vdev,
 		return -EINVAL;
 
 	if (flags & VFIO_IRQ_SET_DATA_NONE) {
-		vfio_pci_intx_mask(vdev);
+		__vfio_pci_intx_mask(vdev);
 	} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
 		uint8_t mask = *(uint8_t *)data;
 		if (mask)
-			vfio_pci_intx_mask(vdev);
+			__vfio_pci_intx_mask(vdev);
 	} else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
 		return -ENOTTY; /* XXX implement me */
 	}
@@ -507,19 +644,23 @@ static int vfio_pci_set_intx_trigger(struct vfio_pci_core_device *vdev,
 		return -EINVAL;
 
 	if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
+		struct eventfd_ctx *trigger = NULL;
 		int32_t fd = *(int32_t *)data;
 		int ret;
 
-		if (is_intx(vdev))
-			return vfio_intx_set_signal(vdev, fd);
+		if (fd >= 0) {
+			trigger = eventfd_ctx_fdget(fd);
+			if (IS_ERR(trigger))
+				return PTR_ERR(trigger);
+		}
 
-		ret = vfio_intx_enable(vdev);
-		if (ret)
-			return ret;
+		if (is_intx(vdev))
+			ret = vfio_intx_set_signal(vdev, trigger);
+		else
+			ret = vfio_intx_enable(vdev, trigger);
 
-		ret = vfio_intx_set_signal(vdev, fd);
-		if (ret)
-			vfio_intx_disable(vdev);
+		if (ret && trigger)
+			eventfd_ctx_put(trigger);
 
 		return ret;
 	}
@@ -528,11 +669,11 @@ static int vfio_pci_set_intx_trigger(struct vfio_pci_core_device *vdev,
 		return -EINVAL;
 
 	if (flags & VFIO_IRQ_SET_DATA_NONE) {
-		vfio_send_intx_eventfd(vdev, NULL);
+		vfio_send_intx_eventfd(vdev, vfio_irq_ctx_get(vdev, 0));
 	} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
 		uint8_t trigger = *(uint8_t *)data;
 		if (trigger)
-			vfio_send_intx_eventfd(vdev, NULL);
+			vfio_send_intx_eventfd(vdev, vfio_irq_ctx_get(vdev, 0));
 	}
 	return 0;
 }
@@ -541,8 +682,9 @@ static int vfio_pci_set_msi_trigger(struct vfio_pci_core_device *vdev,
 				    unsigned index, unsigned start,
 				    unsigned count, uint32_t flags, void *data)
 {
-	int i;
-	bool msix = (index == VFIO_PCI_MSIX_IRQ_INDEX) ? true : false;
+	struct vfio_pci_irq_ctx *ctx;
+	unsigned int i;
+	bool msix = (index == VFIO_PCI_MSIX_IRQ_INDEX);
 
 	if (irq_is(vdev, index) && !count && (flags & VFIO_IRQ_SET_DATA_NONE)) {
 		vfio_msi_disable(vdev, msix);
@@ -571,38 +713,45 @@ static int vfio_pci_set_msi_trigger(struct vfio_pci_core_device *vdev,
 		return ret;
 	}
 
-	if (!irq_is(vdev, index) || start + count > vdev->num_ctx)
+	if (!irq_is(vdev, index))
 		return -EINVAL;
 
 	for (i = start; i < start + count; i++) {
-		if (!vdev->ctx[i].trigger)
+		ctx = vfio_irq_ctx_get(vdev, i);
+		if (!ctx)
 			continue;
 		if (flags & VFIO_IRQ_SET_DATA_NONE) {
-			eventfd_signal(vdev->ctx[i].trigger, 1);
+			eventfd_signal(ctx->trigger);
 		} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
 			uint8_t *bools = data;
 			if (bools[i - start])
-				eventfd_signal(vdev->ctx[i].trigger, 1);
+				eventfd_signal(ctx->trigger);
 		}
 	}
 	return 0;
 }
 
-static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
+static int vfio_pci_set_ctx_trigger_single(struct vfio_pci_core_device *vdev,
+					   struct vfio_pci_eventfd __rcu **peventfd,
 					   unsigned int count, uint32_t flags,
 					   void *data)
 {
 	/* DATA_NONE/DATA_BOOL enables loopback testing */
 	if (flags & VFIO_IRQ_SET_DATA_NONE) {
-		if (*ctx) {
-			if (count) {
-				eventfd_signal(*ctx, 1);
-			} else {
-				eventfd_ctx_put(*ctx);
-				*ctx = NULL;
-			}
+		struct vfio_pci_eventfd *eventfd;
+
+		eventfd = rcu_dereference_protected(*peventfd,
+						lockdep_is_held(&vdev->igate));
+
+		if (!eventfd)
+			return -EINVAL;
+
+		if (count) {
+			eventfd_signal(eventfd->ctx);
 			return 0;
 		}
+
+		return vfio_pci_eventfd_replace_locked(vdev, peventfd, NULL);
 	} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
 		uint8_t trigger;
 
@@ -610,8 +759,15 @@ static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
 			return -EINVAL;
 
 		trigger = *(uint8_t *)data;
-		if (trigger && *ctx)
-			eventfd_signal(*ctx, 1);
+
+		if (trigger) {
+			struct vfio_pci_eventfd *eventfd =
+					rcu_dereference_protected(*peventfd,
+					lockdep_is_held(&vdev->igate));
+
+			if (eventfd)
+				eventfd_signal(eventfd->ctx);
+		}
 
 		return 0;
 	} else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
@@ -622,22 +778,23 @@ static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
 
 		fd = *(int32_t *)data;
 		if (fd == -1) {
-			if (*ctx)
-				eventfd_ctx_put(*ctx);
-			*ctx = NULL;
+			return vfio_pci_eventfd_replace_locked(vdev,
+							       peventfd, NULL);
 		} else if (fd >= 0) {
 			struct eventfd_ctx *efdctx;
+			int ret;
 
 			efdctx = eventfd_ctx_fdget(fd);
 			if (IS_ERR(efdctx))
 				return PTR_ERR(efdctx);
 
-			if (*ctx)
-				eventfd_ctx_put(*ctx);
+			ret = vfio_pci_eventfd_replace_locked(vdev,
+							      peventfd, efdctx);
+			if (ret)
+				eventfd_ctx_put(efdctx);
 
-			*ctx = efdctx;
+			return ret;
 		}
-		return 0;
 	}
 
 	return -EINVAL;
@@ -650,7 +807,7 @@ static int vfio_pci_set_err_trigger(struct vfio_pci_core_device *vdev,
 	if (index != VFIO_PCI_ERR_IRQ_INDEX || start != 0 || count > 1)
 		return -EINVAL;
 
-	return vfio_pci_set_ctx_trigger_single(&vdev->err_trigger,
+	return vfio_pci_set_ctx_trigger_single(vdev, &vdev->err_trigger,
 					       count, flags, data);
 }
 
@@ -661,7 +818,7 @@ static int vfio_pci_set_req_trigger(struct vfio_pci_core_device *vdev,
 	if (index != VFIO_PCI_REQ_IRQ_INDEX || start != 0 || count > 1)
 		return -EINVAL;
 
-	return vfio_pci_set_ctx_trigger_single(&vdev->req_trigger,
+	return vfio_pci_set_ctx_trigger_single(vdev, &vdev->req_trigger,
 					       count, flags, data);
 }