1 files changed, 740 insertions, 0 deletions

diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
new file mode 100644
index 0000000..211a492
--- /dev/null
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -0,0 +1,740 @@
+/*
+ * VFIO PCI interrupt handling
+ *
+ * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
+ *     Author: Alex Williamson <alex.williamson@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Derived from original vfio:
+ * Copyright 2010 Cisco Systems, Inc.  All rights reserved.
+ * Author: Tom Lyon, pugs@cisco.com
+ */
+
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/eventfd.h>
+#include <linux/pci.h>
+#include <linux/file.h>
+#include <linux/poll.h>
+#include <linux/vfio.h>
+#include <linux/wait.h>
+#include <linux/workqueue.h>
+
+#include "vfio_pci_private.h"
+
+/*
+ * IRQfd - generic
+ */
+struct virqfd {
+	struct vfio_pci_device	*vdev;
+	struct eventfd_ctx	*eventfd;
+	int			(*handler)(struct vfio_pci_device *, void *);
+	void			(*thread)(struct vfio_pci_device *, void *);
+	void			*data;
+	struct work_struct	inject;
+	wait_queue_t		wait;
+	poll_table		pt;
+	struct work_struct	shutdown;
+	struct virqfd		**pvirqfd;
+};
+
+static struct workqueue_struct *vfio_irqfd_cleanup_wq;
+
+int __init vfio_pci_virqfd_init(void)
+{
+	vfio_irqfd_cleanup_wq =
+		create_singlethread_workqueue("vfio-irqfd-cleanup");
+	if (!vfio_irqfd_cleanup_wq)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void vfio_pci_virqfd_exit(void)
+{
+	destroy_workqueue(vfio_irqfd_cleanup_wq);
+}
+
+static void virqfd_deactivate(struct virqfd *virqfd)
+{
+	queue_work(vfio_irqfd_cleanup_wq, &virqfd->shutdown);
+}
+
+static int virqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
+{
+	struct virqfd *virqfd = container_of(wait, struct virqfd, wait);
+	unsigned long flags = (unsigned long)key;
+
+	if (flags & POLLIN) {
+		/* An event has been signaled, call function */
+		if ((!virqfd->handler ||
+		     virqfd->handler(virqfd->vdev, virqfd->data)) &&
+		    virqfd->thread)
+			schedule_work(&virqfd->inject);
+	}
+
+	if (flags & POLLHUP)
+		/* The eventfd is closing, detach from VFIO */
+		virqfd_deactivate(virqfd);
+
+	return 0;
+}
+
+static void virqfd_ptable_queue_proc(struct file *file,
+				     wait_queue_head_t *wqh, poll_table *pt)
+{
+	struct virqfd *virqfd = container_of(pt, struct virqfd, pt);
+	add_wait_queue(wqh, &virqfd->wait);
+}
+
+static void virqfd_shutdown(struct work_struct *work)
+{
+	struct virqfd *virqfd = container_of(work, struct virqfd, shutdown);
+	struct virqfd **pvirqfd = virqfd->pvirqfd;
+	u64 cnt;
+
+	eventfd_ctx_remove_wait_queue(virqfd->eventfd, &virqfd->wait, &cnt);
+	flush_work(&virqfd->inject);
+	eventfd_ctx_put(virqfd->eventfd);
+
+	kfree(virqfd);
+	*pvirqfd = NULL;
+}
+
+static void virqfd_inject(struct work_struct *work)
+{
+	struct virqfd *virqfd = container_of(work, struct virqfd, inject);
+	if (virqfd->thread)
+		virqfd->thread(virqfd->vdev, virqfd->data);
+}
+
+static int virqfd_enable(struct vfio_pci_device *vdev,
+			 int (*handler)(struct vfio_pci_device *, void *),
+			 void (*thread)(struct vfio_pci_device *, void *),
+			 void *data, struct virqfd **pvirqfd, int fd)
+{
+	struct file *file = NULL;
+	struct eventfd_ctx *ctx = NULL;
+	struct virqfd *virqfd;
+	int ret = 0;
+	unsigned int events;
+
+	if (*pvirqfd)
+		return -EBUSY;
+
+	virqfd = kzalloc(sizeof(*virqfd), GFP_KERNEL);
+	if (!virqfd)
+		return -ENOMEM;
+
+	virqfd->pvirqfd = pvirqfd;
+	*pvirqfd = virqfd;
+	virqfd->vdev = vdev;
+	virqfd->handler = handler;
+	virqfd->thread = thread;
+	virqfd->data = data;
+
+	INIT_WORK(&virqfd->shutdown, virqfd_shutdown);
+	INIT_WORK(&virqfd->inject, virqfd_inject);
+
+	file = eventfd_fget(fd);
+	if (IS_ERR(file)) {
+		ret = PTR_ERR(file);
+		goto fail;
+	}
+
+	ctx = eventfd_ctx_fileget(file);
+	if (IS_ERR(ctx)) {
+		ret = PTR_ERR(ctx);
+		goto fail;
+	}
+
+	virqfd->eventfd = ctx;
+
+	/*
+	 * Install our own custom wake-up handling so we are notified via
+	 * a callback whenever someone signals the underlying eventfd.
+	 */
+	init_waitqueue_func_entry(&virqfd->wait, virqfd_wakeup);
+	init_poll_funcptr(&virqfd->pt, virqfd_ptable_queue_proc);
+
+	events = file->f_op->poll(file, &virqfd->pt);
+
+	/*
+	 * Check if there was an event already pending on the eventfd
+	 * before we registered and trigger it as if we didn't miss it.
+	 */
+	if (events & POLLIN) {
+		if ((!handler || handler(vdev, data)) && thread)
+			schedule_work(&virqfd->inject);
+	}
+
+	/*
+	 * Do not drop the file until the irqfd is fully initialized,
+	 * otherwise we might race against the POLLHUP.
+	 */
+	fput(file);
+
+	return 0;
+
+fail:
+	if (ctx && !IS_ERR(ctx))
+		eventfd_ctx_put(ctx);
+
+	if (file && !IS_ERR(file))
+		fput(file);
+
+	kfree(virqfd);
+	*pvirqfd = NULL;
+
+	return ret;
+}
+
+static void virqfd_disable(struct virqfd *virqfd)
+{
+	if (!virqfd)
+		return;
+
+	virqfd_deactivate(virqfd);
+
+	/* Block until we know all outstanding shutdown jobs have completed. */
+	flush_workqueue(vfio_irqfd_cleanup_wq);
+}
+
+/*
+ * INTx
+ */
+static void vfio_send_intx_eventfd(struct vfio_pci_device *vdev, void *unused)
+{
+	if (likely(is_intx(vdev) && !vdev->virq_disabled))
+		eventfd_signal(vdev->ctx[0].trigger, 1);
+}
+
+void vfio_pci_intx_mask(struct vfio_pci_device *vdev)
+{
+	struct pci_dev *pdev = vdev->pdev;
+	unsigned long flags;
+
+	spin_lock_irqsave(&vdev->irqlock, flags);
+
+	/*
+	 * Masking can come from interrupt, ioctl, or config space
+	 * via INTx disable.  The latter means this can get called
+	 * even when not using intx delivery.  In this case, just
+	 * try to have the physical bit follow the virtual bit.
+	 */
+	if (unlikely(!is_intx(vdev))) {
+		if (vdev->pci_2_3)
+			pci_intx(pdev, 0);
+	} else if (!vdev->ctx[0].masked) {
+		/*
+		 * Can't use check_and_mask here because we always want to
+		 * mask, not just when something is pending.
+		 */
+		if (vdev->pci_2_3)
+			pci_intx(pdev, 0);
+		else
+			disable_irq_nosync(pdev->irq);
+
+		vdev->ctx[0].masked = true;
+	}
+
+	spin_unlock_irqrestore(&vdev->irqlock, flags);
+}
+
+/*
+ * 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.
+ */
+int vfio_pci_intx_unmask_handler(struct vfio_pci_device *vdev, void *unused)
+{
+	struct pci_dev *pdev = vdev->pdev;
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&vdev->irqlock, flags);
+
+	/*
+	 * Unmasking comes from ioctl or config, so again, have the
+	 * physical bit follow the virtual even when not using INTx.
+	 */
+	if (unlikely(!is_intx(vdev))) {
+		if (vdev->pci_2_3)
+			pci_intx(pdev, 1);
+	} else if (vdev->ctx[0].masked && !vdev->virq_disabled) {
+		/*
+		 * A pending interrupt here would immediately trigger,
+		 * but we can avoid that overhead by just re-sending
+		 * the interrupt to the user.
+		 */
+		if (vdev->pci_2_3) {
+			if (!pci_check_and_unmask_intx(pdev))
+				ret = 1;
+		} else
+			enable_irq(pdev->irq);
+
+		vdev->ctx[0].masked = (ret > 0);
+	}
+
+	spin_unlock_irqrestore(&vdev->irqlock, flags);
+
+	return ret;
+}
+
+void vfio_pci_intx_unmask(struct vfio_pci_device *vdev)
+{
+	if (vfio_pci_intx_unmask_handler(vdev, NULL) > 0)
+		vfio_send_intx_eventfd(vdev, NULL);
+}
+
+static irqreturn_t vfio_intx_handler(int irq, void *dev_id)
+{
+	struct vfio_pci_device *vdev = dev_id;
+	unsigned long flags;
+	int ret = IRQ_NONE;
+
+	spin_lock_irqsave(&vdev->irqlock, flags);
+
+	if (!vdev->pci_2_3) {
+		disable_irq_nosync(vdev->pdev->irq);
+		vdev->ctx[0].masked = true;
+		ret = IRQ_HANDLED;
+	} else if (!vdev->ctx[0].masked &&  /* may be shared */
+		   pci_check_and_mask_intx(vdev->pdev)) {
+		vdev->ctx[0].masked = true;
+		ret = IRQ_HANDLED;
+	}
+
+	spin_unlock_irqrestore(&vdev->irqlock, flags);
+
+	if (ret == IRQ_HANDLED)
+		vfio_send_intx_eventfd(vdev, NULL);
+
+	return ret;
+}
+
+static int vfio_intx_enable(struct vfio_pci_device *vdev)
+{
+	if (!is_irq_none(vdev))
+		return -EINVAL;
+
+	if (!vdev->pdev->irq)
+		return -ENODEV;
+
+	vdev->ctx = kzalloc(sizeof(struct vfio_pci_irq_ctx), GFP_KERNEL);
+	if (!vdev->ctx)
+		return -ENOMEM;
+
+	vdev->num_ctx = 1;
+	vdev->irq_type = VFIO_PCI_INTX_IRQ_INDEX;
+
+	return 0;
+}
+
+static int vfio_intx_set_signal(struct vfio_pci_device *vdev, int fd)
+{
+	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;
+
+	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);
+	}
+
+	if (!vdev->pci_2_3)
+		irqflags = 0;
+
+	ret = request_irq(pdev->irq, vfio_intx_handler,
+			  irqflags, vdev->ctx[0].name, vdev);
+	if (ret) {
+		kfree(vdev->ctx[0].name);
+		eventfd_ctx_put(trigger);
+		return ret;
+	}
+
+	vdev->ctx[0].trigger = trigger;
+
+	/*
+	 * 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 || vdev->virq_disabled))
+		disable_irq_nosync(pdev->irq);
+	spin_unlock_irqrestore(&vdev->irqlock, flags);
+
+	return 0;
+}
+
+static void vfio_intx_disable(struct vfio_pci_device *vdev)
+{
+	vfio_intx_set_signal(vdev, -1);
+	virqfd_disable(vdev->ctx[0].unmask);
+	virqfd_disable(vdev->ctx[0].mask);
+	vdev->irq_type = VFIO_PCI_NUM_IRQS;
+	vdev->num_ctx = 0;
+	kfree(vdev->ctx);
+}
+
+/*
+ * MSI/MSI-X
+ */
+static irqreturn_t vfio_msihandler(int irq, void *arg)
+{
+	struct eventfd_ctx *trigger = arg;
+
+	eventfd_signal(trigger, 1);
+	return IRQ_HANDLED;
+}
+
+static int vfio_msi_enable(struct vfio_pci_device *vdev, int nvec, bool msix)
+{
+	struct pci_dev *pdev = vdev->pdev;
+	int ret;
+
+	if (!is_irq_none(vdev))
+		return -EINVAL;
+
+	vdev->ctx = kzalloc(nvec * sizeof(struct vfio_pci_irq_ctx), GFP_KERNEL);
+	if (!vdev->ctx)
+		return -ENOMEM;
+
+	if (msix) {
+		int i;
+
+		vdev->msix = kzalloc(nvec * sizeof(struct msix_entry),
+				     GFP_KERNEL);
+		if (!vdev->msix) {
+			kfree(vdev->ctx);
+			return -ENOMEM;
+		}
+
+		for (i = 0; i < nvec; i++)
+			vdev->msix[i].entry = i;
+
+		ret = pci_enable_msix(pdev, vdev->msix, nvec);
+		if (ret) {
+			kfree(vdev->msix);
+			kfree(vdev->ctx);
+			return ret;
+		}
+	} else {
+		ret = pci_enable_msi_block(pdev, nvec);
+		if (ret) {
+			kfree(vdev->ctx);
+			return ret;
+		}
+	}
+
+	vdev->num_ctx = nvec;
+	vdev->irq_type = msix ? VFIO_PCI_MSIX_IRQ_INDEX :
+				VFIO_PCI_MSI_IRQ_INDEX;
+
+	if (!msix) {
+		/*
+		 * Compute the virtual hardware field for max msi vectors -
+		 * it is the log base 2 of the number of vectors.
+		 */
+		vdev->msi_qmax = fls(nvec * 2 - 1) - 1;
+	}
+
+	return 0;
+}
+
+static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev,
+				      int vector, int fd, bool msix)
+{
+	struct pci_dev *pdev = vdev->pdev;
+	int irq = msix ? vdev->msix[vector].vector : pdev->irq + vector;
+	char *name = msix ? "vfio-msix" : "vfio-msi";
+	struct eventfd_ctx *trigger;
+	int ret;
+
+	if (vector >= vdev->num_ctx)
+		return -EINVAL;
+
+	if (vdev->ctx[vector].trigger) {
+		free_irq(irq, vdev->ctx[vector].trigger);
+		kfree(vdev->ctx[vector].name);
+		eventfd_ctx_put(vdev->ctx[vector].trigger);
+		vdev->ctx[vector].trigger = NULL;
+	}
+
+	if (fd < 0)
+		return 0;
+
+	vdev->ctx[vector].name = kasprintf(GFP_KERNEL, "%s[%d](%s)",
+					   name, vector, pci_name(pdev));
+	if (!vdev->ctx[vector].name)
+		return -ENOMEM;
+
+	trigger = eventfd_ctx_fdget(fd);
+	if (IS_ERR(trigger)) {
+		kfree(vdev->ctx[vector].name);
+		return PTR_ERR(trigger);
+	}
+
+	ret = request_irq(irq, vfio_msihandler, 0,
+			  vdev->ctx[vector].name, trigger);
+	if (ret) {
+		kfree(vdev->ctx[vector].name);
+		eventfd_ctx_put(trigger);
+		return ret;
+	}
+
+	vdev->ctx[vector].trigger = trigger;
+
+	return 0;
+}
+
+static int vfio_msi_set_block(struct vfio_pci_device *vdev, unsigned start,
+			      unsigned count, int32_t *fds, bool msix)
+{
+	int i, j, ret = 0;
+
+	if (start + count > vdev->num_ctx)
+		return -EINVAL;
+
+	for (i = 0, j = start; i < count && !ret; i++, j++) {
+		int fd = fds ? fds[i] : -1;
+		ret = vfio_msi_set_vector_signal(vdev, j, fd, msix);
+	}
+
+	if (ret) {
+		for (--j; j >= start; j--)
+			vfio_msi_set_vector_signal(vdev, j, -1, msix);
+	}
+
+	return ret;
+}
+
+static void vfio_msi_disable(struct vfio_pci_device *vdev, bool msix)
+{
+	struct pci_dev *pdev = vdev->pdev;
+	int i;
+
+	vfio_msi_set_block(vdev, 0, vdev->num_ctx, NULL, msix);
+
+	for (i = 0; i < vdev->num_ctx; i++) {
+		virqfd_disable(vdev->ctx[i].unmask);
+		virqfd_disable(vdev->ctx[i].mask);
+	}
+
+	if (msix) {
+		pci_disable_msix(vdev->pdev);
+		kfree(vdev->msix);
+	} else
+		pci_disable_msi(pdev);
+
+	vdev->irq_type = VFIO_PCI_NUM_IRQS;
+	vdev->num_ctx = 0;
+	kfree(vdev->ctx);
+}
+
+/*
+ * IOCTL support
+ */
+static int vfio_pci_set_intx_unmask(struct vfio_pci_device *vdev,
+				    unsigned index, unsigned start,
+				    unsigned count, uint32_t flags, void *data)
+{
+	if (!is_intx(vdev) || start != 0 || count != 1)
+		return -EINVAL;
+
+	if (flags & VFIO_IRQ_SET_DATA_NONE) {
+		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);
+	} else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
+		int32_t fd = *(int32_t *)data;
+		if (fd >= 0)
+			return virqfd_enable(vdev, vfio_pci_intx_unmask_handler,
+					     vfio_send_intx_eventfd, NULL,
+					     &vdev->ctx[0].unmask, fd);
+
+		virqfd_disable(vdev->ctx[0].unmask);
+	}
+
+	return 0;
+}
+
+static int vfio_pci_set_intx_mask(struct vfio_pci_device *vdev,
+				  unsigned index, unsigned start,
+				  unsigned count, uint32_t flags, void *data)
+{
+	if (!is_intx(vdev) || start != 0 || count != 1)
+		return -EINVAL;
+
+	if (flags & VFIO_IRQ_SET_DATA_NONE) {
+		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);
+	} else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
+		return -ENOTTY; /* XXX implement me */
+	}
+
+	return 0;
+}
+
+static int vfio_pci_set_intx_trigger(struct vfio_pci_device *vdev,
+				     unsigned index, unsigned start,
+				     unsigned count, uint32_t flags, void *data)
+{
+	if (is_intx(vdev) && !count && (flags & VFIO_IRQ_SET_DATA_NONE)) {
+		vfio_intx_disable(vdev);
+		return 0;
+	}
+
+	if (!(is_intx(vdev) || is_irq_none(vdev)) || start != 0 || count != 1)
+		return -EINVAL;
+
+	if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
+		int32_t fd = *(int32_t *)data;
+		int ret;
+
+		if (is_intx(vdev))
+			return vfio_intx_set_signal(vdev, fd);
+
+		ret = vfio_intx_enable(vdev);
+		if (ret)
+			return ret;
+
+		ret = vfio_intx_set_signal(vdev, fd);
+		if (ret)
+			vfio_intx_disable(vdev);
+
+		return ret;
+	}
+
+	if (!is_intx(vdev))
+		return -EINVAL;
+
+	if (flags & VFIO_IRQ_SET_DATA_NONE) {
+		vfio_send_intx_eventfd(vdev, NULL);
+	} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
+		uint8_t trigger = *(uint8_t *)data;
+		if (trigger)
+			vfio_send_intx_eventfd(vdev, NULL);
+	}
+	return 0;
+}
+
+static int vfio_pci_set_msi_trigger(struct vfio_pci_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;
+
+	if (irq_is(vdev, index) && !count && (flags & VFIO_IRQ_SET_DATA_NONE)) {
+		vfio_msi_disable(vdev, msix);
+		return 0;
+	}
+
+	if (!(irq_is(vdev, index) || is_irq_none(vdev)))
+		return -EINVAL;
+
+	if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
+		int32_t *fds = data;
+		int ret;
+
+		if (vdev->irq_type == index)
+			return vfio_msi_set_block(vdev, start, count,
+						  fds, msix);
+
+		ret = vfio_msi_enable(vdev, start + count, msix);
+		if (ret)
+			return ret;
+
+		ret = vfio_msi_set_block(vdev, start, count, fds, msix);
+		if (ret)
+			vfio_msi_disable(vdev, msix);
+
+		return ret;
+	}
+
+	if (!irq_is(vdev, index) || start + count > vdev->num_ctx)
+		return -EINVAL;
+
+	for (i = start; i < start + count; i++) {
+		if (!vdev->ctx[i].trigger)
+			continue;
+		if (flags & VFIO_IRQ_SET_DATA_NONE) {
+			eventfd_signal(vdev->ctx[i].trigger, 1);
+		} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
+			uint8_t *bools = data;
+			if (bools[i - start])
+				eventfd_signal(vdev->ctx[i].trigger, 1);
+		}
+	}
+	return 0;
+}
+
+int vfio_pci_set_irqs_ioctl(struct vfio_pci_device *vdev, uint32_t flags,
+			    unsigned index, unsigned start, unsigned count,
+			    void *data)
+{
+	int (*func)(struct vfio_pci_device *vdev, unsigned index,
+		    unsigned start, unsigned count, uint32_t flags,
+		    void *data) = NULL;
+
+	switch (index) {
+	case VFIO_PCI_INTX_IRQ_INDEX:
+		switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
+		case VFIO_IRQ_SET_ACTION_MASK:
+			func = vfio_pci_set_intx_mask;
+			break;
+		case VFIO_IRQ_SET_ACTION_UNMASK:
+			func = vfio_pci_set_intx_unmask;
+			break;
+		case VFIO_IRQ_SET_ACTION_TRIGGER:
+			func = vfio_pci_set_intx_trigger;
+			break;
+		}
+		break;
+	case VFIO_PCI_MSI_IRQ_INDEX:
+	case VFIO_PCI_MSIX_IRQ_INDEX:
+		switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
+		case VFIO_IRQ_SET_ACTION_MASK:
+		case VFIO_IRQ_SET_ACTION_UNMASK:
+			/* XXX Need masking support exported */
+			break;
+		case VFIO_IRQ_SET_ACTION_TRIGGER:
+			func = vfio_pci_set_msi_trigger;
+			break;
+		}
+		break;
+	}
+
+	if (!func)
+		return -ENOTTY;
+
+	return func(vdev, index, start, count, flags, data);
+}