Commit c086de81 authored by Kirti Wankhede's avatar Kirti Wankhede Committed by Alex Williamson
Browse files

vfio iommu: Add blocking notifier to notify DMA_UNMAP 



Added blocking notifier to IOMMU TYPE1 driver to notify vendor drivers
about DMA_UNMAP.
Exported two APIs vfio_register_notifier() and vfio_unregister_notifier().
Notifier should be registered, if external user wants to use
vfio_pin_pages()/vfio_unpin_pages() APIs to pin/unpin pages.
Vendor driver should use VFIO_IOMMU_NOTIFY_DMA_UNMAP action to invalidate
mappings.

Signed-off-by: default avatarKirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: default avatarNeo Jia <cjia@nvidia.com>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent a54eb550

drivers/vfio/vfio.c

+73 −0
Original line number Diff line number Diff line
@@ -1901,6 +1901,79 @@ err_unpin_pages: 
}

EXPORT_SYMBOL(vfio_unpin_pages);



int vfio_register_notifier(struct device *dev, struct notifier_block *nb)

{

	struct vfio_container *container;

	struct vfio_group *group;

	struct vfio_iommu_driver *driver;

	int ret;



	if (!dev || !nb)

		return -EINVAL;



	group = vfio_group_get_from_dev(dev);

	if (IS_ERR(group))

		return PTR_ERR(group);



	ret = vfio_group_add_container_user(group);

	if (ret)

		goto err_register_nb;



	container = group->container;

	down_read(&container->group_lock);



	driver = container->iommu_driver;

	if (likely(driver && driver->ops->register_notifier))

		ret = driver->ops->register_notifier(container->iommu_data, nb);

	else

		ret = -ENOTTY;



	up_read(&container->group_lock);

	vfio_group_try_dissolve_container(group);



err_register_nb:

	vfio_group_put(group);

	return ret;

}

EXPORT_SYMBOL(vfio_register_notifier);



int vfio_unregister_notifier(struct device *dev, struct notifier_block *nb)

{

	struct vfio_container *container;

	struct vfio_group *group;

	struct vfio_iommu_driver *driver;

	int ret;



	if (!dev || !nb)

		return -EINVAL;



	group = vfio_group_get_from_dev(dev);

	if (IS_ERR(group))

		return PTR_ERR(group);



	ret = vfio_group_add_container_user(group);

	if (ret)

		goto err_unregister_nb;



	container = group->container;

	down_read(&container->group_lock);



	driver = container->iommu_driver;

	if (likely(driver && driver->ops->unregister_notifier))

		ret = driver->ops->unregister_notifier(container->iommu_data,

						       nb);

	else

		ret = -ENOTTY;



	up_read(&container->group_lock);

	vfio_group_try_dissolve_container(group);



err_unregister_nb:

	vfio_group_put(group);

	return ret;

}

EXPORT_SYMBOL(vfio_unregister_notifier);



/**

 * Module/class support

 */

drivers/vfio/vfio_iommu_type1.c

+61 −13
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ 
#include <linux/workqueue.h>

#include <linux/pid_namespace.h>

#include <linux/mdev.h>

#include <linux/notifier.h>



#define DRIVER_VERSION  "0.2"

#define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@redhat.com>"
@@ -60,6 +61,7 @@ struct vfio_iommu { 
	struct vfio_domain	*external_domain; /* domain for external user */

	struct mutex		lock;

	struct rb_root		dma_list;

	struct blocking_notifier_head notifier;

	bool			v2;

	bool			nesting;

};
@@ -561,7 +563,8 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data, 


	mutex_lock(&iommu->lock);



	if (!iommu->external_domain) {

	/* Fail if notifier list is empty */

	if ((!iommu->external_domain) || (!iommu->notifier.head)) {

		ret = -EINVAL;

		goto pin_done;

	}
@@ -776,9 +779,9 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, 
			     struct vfio_iommu_type1_dma_unmap *unmap)

{

	uint64_t mask;

	struct vfio_dma *dma;

	struct vfio_dma *dma, *dma_last = NULL;

	size_t unmapped = 0;

	int ret = 0;

	int ret = 0, retries = 0;



	mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1;
@@ -788,7 +791,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, 
		return -EINVAL;



	WARN_ON(mask & PAGE_MASK);



again:

	mutex_lock(&iommu->lock);



	/*
@@ -844,6 +847,32 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, 
		 */

		if (dma->task->mm != current->mm)

			break;



		if (!RB_EMPTY_ROOT(&dma->pfn_list)) {

			struct vfio_iommu_type1_dma_unmap nb_unmap;



			if (dma_last == dma) {

				BUG_ON(++retries > 10);

			} else {

				dma_last = dma;

				retries = 0;

			}



			nb_unmap.iova = dma->iova;

			nb_unmap.size = dma->size;



			/*

			 * Notify anyone (mdev vendor drivers) to invalidate and

			 * unmap iovas within the range we're about to unmap.

			 * Vendor drivers MUST unpin pages in response to an

			 * invalidation.

			 */

			mutex_unlock(&iommu->lock);

			blocking_notifier_call_chain(&iommu->notifier,

						    VFIO_IOMMU_NOTIFY_DMA_UNMAP,

						    &nb_unmap);

			goto again;

		}

		unmapped += dma->size;

		vfio_remove_dma(iommu, dma);

	}
@@ -1419,6 +1448,7 @@ static void *vfio_iommu_type1_open(unsigned long arg) 
	INIT_LIST_HEAD(&iommu->domain_list);

	iommu->dma_list = RB_ROOT;

	mutex_init(&iommu->lock);

	BLOCKING_INIT_NOTIFIER_HEAD(&iommu->notifier);



	return iommu;

}
@@ -1553,6 +1583,22 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, 
	return -ENOTTY;

}



static int vfio_iommu_type1_register_notifier(void *iommu_data,

					      struct notifier_block *nb)

{

	struct vfio_iommu *iommu = iommu_data;



	return blocking_notifier_chain_register(&iommu->notifier, nb);

}



static int vfio_iommu_type1_unregister_notifier(void *iommu_data,

						struct notifier_block *nb)

{

	struct vfio_iommu *iommu = iommu_data;



	return blocking_notifier_chain_unregister(&iommu->notifier, nb);

}



static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = {

	.name			= "vfio-iommu-type1",

	.owner			= THIS_MODULE,
@@ -1563,6 +1609,8 @@ static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = { 
	.detach_group		= vfio_iommu_type1_detach_group,

	.pin_pages		= vfio_iommu_type1_pin_pages,

	.unpin_pages		= vfio_iommu_type1_unpin_pages,

	.register_notifier	= vfio_iommu_type1_register_notifier,

	.unregister_notifier	= vfio_iommu_type1_unregister_notifier,

};



static int __init vfio_iommu_type1_init(void)

include/linux/vfio.h

+12 −0
Original line number Diff line number Diff line
@@ -80,6 +80,10 @@ struct vfio_iommu_driver_ops { 
				     unsigned long *phys_pfn);

	int		(*unpin_pages)(void *iommu_data,

				       unsigned long *user_pfn, int npage);

	int		(*register_notifier)(void *iommu_data,

					     struct notifier_block *nb);

	int		(*unregister_notifier)(void *iommu_data,

					       struct notifier_block *nb);

};



extern int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops *ops);
@@ -103,6 +107,14 @@ extern int vfio_pin_pages(struct device *dev, unsigned long *user_pfn, 
extern int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn,

			    int npage);



#define VFIO_IOMMU_NOTIFY_DMA_UNMAP	(1)



extern int vfio_register_notifier(struct device *dev,

				  struct notifier_block *nb);



extern int vfio_unregister_notifier(struct device *dev,

				    struct notifier_block *nb);



/*

 * Sub-module helpers

 */

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