drivers/vfio/pci/vfio_pci_intrs.c - kernel/msm-4.9 - Gitiles

 /*
  * 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/msi.h>
 #include <linux/pci.h>
 #include <linux/file.h>
 #include <linux/vfio.h>
 #include <linux/wait.h>
 #include <linux/slab.h>

 #include "vfio_pci_private.h"

 /*
  * INTx
  */
 static void vfio_send_intx_eventfd(void *opaque, void *unused)
 {
 	struct vfio_pci_device *vdev = opaque;

 	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.
  */
 static int vfio_pci_intx_unmask_handler(void *opaque, void *unused)
 {
 	struct vfio_pci_device *vdev = opaque;
 	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;

 	/*
 	 * 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.
 	 */
 	vdev->ctx[0].masked = vdev->virq_disabled;
 	if (vdev->pci_2_3)
 		pci_intx(vdev->pdev, !vdev->ctx[0].masked);

 	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);
 	}

 	vdev->ctx[0].trigger = trigger;

 	if (!vdev->pci_2_3)
 		irqflags = 0;

 	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;
 	}

 	/*
 	 * 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_device *vdev)
 {
 	vfio_virqfd_disable(&vdev->ctx[0].unmask);
 	vfio_virqfd_disable(&vdev->ctx[0].mask);
 	vfio_intx_set_signal(vdev, -1);
 	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_range(pdev, vdev->msix, 1, nvec);
 		if (ret < nvec) {
 			if (ret > 0)
 				pci_disable_msix(pdev);
 			kfree(vdev->msix);
 			kfree(vdev->ctx);
 			return ret;
 		}
 	} else {
 		ret = pci_enable_msi_range(pdev, 1, nvec);
 		if (ret < nvec) {
 			if (ret > 0)
 				pci_disable_msi(pdev);
 			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;
 	struct eventfd_ctx *trigger;
 	int irq, ret;

 	if (vector < 0 || vector >= vdev->num_ctx)
 		return -EINVAL;

 	irq = msix ? vdev->msix[vector].vector : pdev->irq + vector;

 	if (vdev->ctx[vector].trigger) {
 		free_irq(irq, vdev->ctx[vector].trigger);
 		irq_bypass_unregister_producer(&vdev->ctx[vector].producer);
 		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, "vfio-msi%s[%d](%s)",
 					   msix ? "x" : "", 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);
 	}

 	/*
 	 * 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 (msix) {
 		struct msi_msg msg;

 		get_cached_msi_msg(irq, &msg);
 		pci_write_msi_msg(irq, &msg);
 	}

 	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].producer.token = trigger;
 	vdev->ctx[vector].producer.irq = irq;
 	ret = irq_bypass_register_producer(&vdev->ctx[vector].producer);
 	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].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 >= vdev->num_ctx || 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 >= (int)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;

 	for (i = 0; i < vdev->num_ctx; i++) {
 		vfio_virqfd_disable(&vdev->ctx[i].unmask);
 		vfio_virqfd_disable(&vdev->ctx[i].mask);
 	}

 	vfio_msi_set_block(vdev, 0, vdev->num_ctx, NULL, msix);

 	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 vfio_virqfd_enable((void *) vdev,
 						  vfio_pci_intx_unmask_handler,
 						  vfio_send_intx_eventfd, NULL,
 						  &vdev->ctx[0].unmask, fd);

 		vfio_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;
 }

 static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
 					   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;
 			}
 			return 0;
 		}
 	} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
 		uint8_t trigger;

 		if (!count)
 			return -EINVAL;

 		trigger = *(uint8_t *)data;
 		if (trigger && *ctx)
 			eventfd_signal(*ctx, 1);

 		return 0;
 	} else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
 		int32_t fd;

 		if (!count)
 			return -EINVAL;

 		fd = *(int32_t *)data;
 		if (fd == -1) {
 			if (*ctx)
 				eventfd_ctx_put(*ctx);
 			*ctx = NULL;
 		} else if (fd >= 0) {
 			struct eventfd_ctx *efdctx;

 			efdctx = eventfd_ctx_fdget(fd);
 			if (IS_ERR(efdctx))
 				return PTR_ERR(efdctx);

 			if (*ctx)
 				eventfd_ctx_put(*ctx);

 			*ctx = efdctx;
 		}
 		return 0;
 	}

 	return -EINVAL;
 }

 static int vfio_pci_set_err_trigger(struct vfio_pci_device *vdev,
 				    unsigned index, unsigned start,
 				    unsigned count, uint32_t flags, void *data)
 {
 	if (index != VFIO_PCI_ERR_IRQ_INDEX || start != 0 || count > 1)
 		return -EINVAL;

 	return vfio_pci_set_ctx_trigger_single(&vdev->err_trigger,
 					       count, flags, data);
 }

 static int vfio_pci_set_req_trigger(struct vfio_pci_device *vdev,
 				    unsigned index, unsigned start,
 				    unsigned count, uint32_t flags, void *data)
 {
 	if (index != VFIO_PCI_REQ_IRQ_INDEX || start != 0 || count > 1)
 		return -EINVAL;

 	return vfio_pci_set_ctx_trigger_single(&vdev->req_trigger,
 					       count, flags, data);
 }

 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;
 	case VFIO_PCI_ERR_IRQ_INDEX:
 		switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
 		case VFIO_IRQ_SET_ACTION_TRIGGER:
 			if (pci_is_pcie(vdev->pdev))
 				func = vfio_pci_set_err_trigger;
 			break;
 		}
 		break;
 	case VFIO_PCI_REQ_IRQ_INDEX:
 		switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
 		case VFIO_IRQ_SET_ACTION_TRIGGER:
 			func = vfio_pci_set_req_trigger;
 			break;
 		}
 		break;
 	}

 	if (!func)
 		return -ENOTTY;

 	return func(vdev, index, start, count, flags, data);
 }
	/*
	* 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/msi.h>
	#include <linux/pci.h>
	#include <linux/file.h>
	#include <linux/vfio.h>
	#include <linux/wait.h>
	#include <linux/slab.h>

	#include "vfio_pci_private.h"

	/*
	* INTx
	*/
	static void vfio_send_intx_eventfd(void opaque, void unused)
	{
	struct vfio_pci_device *vdev = opaque;

	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.
	*/
	static int vfio_pci_intx_unmask_handler(void opaque, void unused)
	{
	struct vfio_pci_device *vdev = opaque;
	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;

	/*
	* 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.
	*/
	vdev->ctx[0].masked = vdev->virq_disabled;
	if (vdev->pci_2_3)
	pci_intx(vdev->pdev, !vdev->ctx[0].masked);

	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);
	}

	vdev->ctx[0].trigger = trigger;

	if (!vdev->pci_2_3)
	irqflags = 0;

	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;
	}

	/*
	* 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_device *vdev)
	{
	vfio_virqfd_disable(&vdev->ctx[0].unmask);
	vfio_virqfd_disable(&vdev->ctx[0].mask);
	vfio_intx_set_signal(vdev, -1);
	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_range(pdev, vdev->msix, 1, nvec);
	if (ret < nvec) {
	if (ret > 0)
	pci_disable_msix(pdev);
	kfree(vdev->msix);
	kfree(vdev->ctx);
	return ret;
	}
	} else {
	ret = pci_enable_msi_range(pdev, 1, nvec);
	if (ret < nvec) {
	if (ret > 0)
	pci_disable_msi(pdev);
	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;
	struct eventfd_ctx *trigger;
	int irq, ret;

	if (vector < 0 \|\| vector >= vdev->num_ctx)
	return -EINVAL;

	irq = msix ? vdev->msix[vector].vector : pdev->irq + vector;

	if (vdev->ctx[vector].trigger) {
	free_irq(irq, vdev->ctx[vector].trigger);
	irq_bypass_unregister_producer(&vdev->ctx[vector].producer);
	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, "vfio-msi%s[%d](%s)",
	msix ? "x" : "", 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);
	}

	/*
	* 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 (msix) {
	struct msi_msg msg;

	get_cached_msi_msg(irq, &msg);
	pci_write_msi_msg(irq, &msg);
	}

	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].producer.token = trigger;
	vdev->ctx[vector].producer.irq = irq;
	ret = irq_bypass_register_producer(&vdev->ctx[vector].producer);
	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].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 >= vdev->num_ctx \|\| 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 >= (int)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;

	for (i = 0; i < vdev->num_ctx; i++) {
	vfio_virqfd_disable(&vdev->ctx[i].unmask);
	vfio_virqfd_disable(&vdev->ctx[i].mask);
	}

	vfio_msi_set_block(vdev, 0, vdev->num_ctx, NULL, msix);

	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 vfio_virqfd_enable((void *) vdev,
	vfio_pci_intx_unmask_handler,
	vfio_send_intx_eventfd, NULL,
	&vdev->ctx[0].unmask, fd);

	vfio_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;
	}

	static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx,
	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;
	}
	return 0;
	}
	} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
	uint8_t trigger;

	if (!count)
	return -EINVAL;

	trigger = (uint8_t )data;
	if (trigger && *ctx)
	eventfd_signal(*ctx, 1);

	return 0;
	} else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
	int32_t fd;

	if (!count)
	return -EINVAL;

	fd = (int32_t )data;
	if (fd == -1) {
	if (*ctx)
	eventfd_ctx_put(*ctx);
	*ctx = NULL;
	} else if (fd >= 0) {
	struct eventfd_ctx *efdctx;

	efdctx = eventfd_ctx_fdget(fd);
	if (IS_ERR(efdctx))
	return PTR_ERR(efdctx);

	if (*ctx)
	eventfd_ctx_put(*ctx);

	*ctx = efdctx;
	}
	return 0;
	}

	return -EINVAL;
	}

	static int vfio_pci_set_err_trigger(struct vfio_pci_device *vdev,
	unsigned index, unsigned start,
	unsigned count, uint32_t flags, void *data)
	{
	if (index != VFIO_PCI_ERR_IRQ_INDEX \|\| start != 0 \|\| count > 1)
	return -EINVAL;

	return vfio_pci_set_ctx_trigger_single(&vdev->err_trigger,
	count, flags, data);
	}

	static int vfio_pci_set_req_trigger(struct vfio_pci_device *vdev,
	unsigned index, unsigned start,
	unsigned count, uint32_t flags, void *data)
	{
	if (index != VFIO_PCI_REQ_IRQ_INDEX \|\| start != 0 \|\| count > 1)
	return -EINVAL;

	return vfio_pci_set_ctx_trigger_single(&vdev->req_trigger,
	count, flags, data);
	}

	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;
	case VFIO_PCI_ERR_IRQ_INDEX:
	switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
	case VFIO_IRQ_SET_ACTION_TRIGGER:
	if (pci_is_pcie(vdev->pdev))
	func = vfio_pci_set_err_trigger;
	break;
	}
	break;
	case VFIO_PCI_REQ_IRQ_INDEX:
	switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
	case VFIO_IRQ_SET_ACTION_TRIGGER:
	func = vfio_pci_set_req_trigger;
	break;
	}
	break;
	}

	if (!func)
	return -ENOTTY;

	return func(vdev, index, start, count, flags, data);
	}