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    Subject[PATCH v11 11/22] vfio iommu: Add blocking notifier to notify DMA_UNMAP
    Date
    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>
    Change-Id: I5910d0024d6be87f3e8d3e0ca0eaeaaa0b17f271
    ---
    drivers/vfio/vfio.c | 73 +++++++++++++++++++++++++++++++++++++++++
    drivers/vfio/vfio_iommu_type1.c | 47 ++++++++++++++++++++------
    include/linux/vfio.h | 11 +++++++
    3 files changed, 121 insertions(+), 10 deletions(-)

    diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
    index 76d260e98930..4ed1a6a247c6 100644
    --- a/drivers/vfio/vfio.c
    +++ b/drivers/vfio/vfio.c
    @@ -1895,6 +1895,79 @@ 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;
    + ssize_t 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 = -EINVAL;
    +
    + 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;
    + ssize_t 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 = -EINVAL;
    +
    + 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
    */
    diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
    index e511073446a0..c2d3a84c447b 100644
    --- a/drivers/vfio/vfio_iommu_type1.c
    +++ b/drivers/vfio/vfio_iommu_type1.c
    @@ -37,6 +37,7 @@
    #include <linux/vfio.h>
    #include <linux/workqueue.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;
    };
    @@ -550,7 +552,8 @@ 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;
    }
    @@ -867,6 +870,11 @@ unlock:
    /* Report how much was unmapped */
    unmap->size = unmapped;

    + if (unmapped && iommu->external_domain)
    + blocking_notifier_call_chain(&iommu->notifier,
    + VFIO_IOMMU_NOTIFY_DMA_UNMAP,
    + unmap);
    +
    return ret;
    }

    @@ -1474,6 +1482,7 @@ static void *vfio_iommu_type1_open(unsigned long arg)
    INIT_LIST_HEAD(&iommu->addr_space_list);
    iommu->dma_list = RB_ROOT;
    mutex_init(&iommu->lock);
    + BLOCKING_INIT_NOTIFIER_HEAD(&iommu->notifier);

    return iommu;
    }
    @@ -1610,16 +1619,34 @@ 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)
    diff --git a/include/linux/vfio.h b/include/linux/vfio.h
    index ba1b64cb7d4b..dcda8fccefab 100644
    --- a/include/linux/vfio.h
    +++ b/include/linux/vfio.h
    @@ -82,6 +82,10 @@ struct vfio_iommu_driver_ops {
    unsigned long *user_pfn,
    unsigned long *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);
    @@ -139,6 +143,13 @@ extern int vfio_pin_pages(struct device *dev, unsigned long *user_pfn,
    extern int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn,
    unsigned long *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);
    /*
    * IRQfd - generic
    */
    --
    2.7.0
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