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vfio iommu: Add blocking notifier to notify DMA_UNMAP
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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: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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Kirti Wankhede authored and Alex Williamson committed Nov 17, 2016
1 parent a54eb55 commit c086de8
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Showing 3 changed files with 146 additions and 13 deletions.
73 changes: 73 additions & 0 deletions drivers/vfio/vfio.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1901,6 +1901,79 @@ int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn, int npage)
}
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
*/
Expand Down
74 changes: 61 additions & 13 deletions drivers/vfio/vfio_iommu_type1.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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>"
Expand All @@ -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;
};
Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -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;

Expand All @@ -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);

/*
Expand Down Expand Up @@ -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);
}
Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -1553,16 +1583,34 @@ 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,
.open = vfio_iommu_type1_open,
.release = vfio_iommu_type1_release,
.ioctl = vfio_iommu_type1_ioctl,
.attach_group = vfio_iommu_type1_attach_group,
.detach_group = vfio_iommu_type1_detach_group,
.pin_pages = vfio_iommu_type1_pin_pages,
.unpin_pages = vfio_iommu_type1_unpin_pages,
.name = "vfio-iommu-type1",
.owner = THIS_MODULE,
.open = vfio_iommu_type1_open,
.release = vfio_iommu_type1_release,
.ioctl = vfio_iommu_type1_ioctl,
.attach_group = vfio_iommu_type1_attach_group,
.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)
Expand Down
12 changes: 12 additions & 0 deletions include/linux/vfio.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand All @@ -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
*/
Expand Down

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