On Fri, 18 Nov 2016 19:01:47 +0800
Jike Song <jike.song@xxxxxxxxx> wrote:
> Currently vfio_register_notifier assumes that there is only one
> notifier chain, which is in vfio_iommu. However, the user might
> also be interested in events other than vfio_iommu, for example,
> vfio_group. Refactor vfio_{un}register_notifier implementation
> to make it feasible.
>
> Cc: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Cc: Kirti Wankhede <kwankhede@xxxxxxxxxx>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Cc: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
> Signed-off-by: Jike Song <jike.song@xxxxxxxxx>
> ---
> drivers/vfio/vfio.c | 87 +++++++++++++++++++++++++++++++++++++++-------------
> include/linux/vfio.h | 16 ++++++++--
> 2 files changed, 78 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
> index c815067..ec62bec 100644
> --- a/drivers/vfio/vfio.c
> +++ b/drivers/vfio/vfio.c
> @@ -2007,23 +2007,24 @@ 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)
> +static int vfio_register_iommu_notifier(struct vfio_group *group,
> + unsigned long *events,
> + struct notifier_block *nb)
> {
> struct vfio_container *container;
> - struct vfio_group *group;
> struct vfio_iommu_driver *driver;
> int ret;
>
> - if (!dev || !nb)
> - return -EINVAL;
> + /* clear known events */
> + *events &= ~VFIO_IOMMU_NOTIFY_DMA_UNMAP;
>
> - group = vfio_group_get_from_dev(dev);
> - if (IS_ERR(group))
> - return PTR_ERR(group);
> + /* refuse to register if still events remaining */
> + if (*events)
> + return -EINVAL;
>
> ret = vfio_group_add_container_user(group);
> if (ret)
> - goto err_register_nb;
> + return -EINVAL;
>
> container = group->container;
> down_read(&container->group_lock);
> @@ -2037,29 +2038,19 @@ int vfio_register_notifier(struct device *dev, struct notifier_block *nb)
> 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)
> +static int vfio_unregister_iommu_notifier(struct vfio_group *group,
> + 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;
> + return -EINVAL;
>
> container = group->container;
> down_read(&container->group_lock);
> @@ -2074,7 +2065,59 @@ int vfio_unregister_notifier(struct device *dev, struct notifier_block *nb)
> up_read(&container->group_lock);
> vfio_group_try_dissolve_container(group);
>
> -err_unregister_nb:
> + return ret;
> +}
> +
> +int vfio_register_notifier(struct device *dev, vfio_notify_type_t type,
> + unsigned long *events,
> + struct notifier_block *nb)
> +{
> + struct vfio_group *group;
> + int ret;
> +
> + if (!dev || !nb)
> + return -EINVAL;
> + if (!events || *events == 0)
> + return -EINVAL;
nit, we could test all these within a single if()
> +
> + group = vfio_group_get_from_dev(dev);
> + if (IS_ERR(group))
> + return PTR_ERR(group);
> +
> + switch (type) {
> + case VFIO_IOMMU_NOTIFY:
> + ret = vfio_register_iommu_notifier(group, events, nb);
> + break;
> + default:
> + ret = EINVAL;
-EINVAL
^
> + }
> +
> + vfio_group_put(group);
> + return ret;
> +}
> +EXPORT_SYMBOL(vfio_register_notifier);
> +
> +int vfio_unregister_notifier(struct device *dev, vfio_notify_type_t type,
> + struct notifier_block *nb)
> +{
> + struct vfio_group *group;
> + int ret;
> +
> + if (!dev || !nb)
> + return -EINVAL;
> +
> + group = vfio_group_get_from_dev(dev);
> + if (IS_ERR(group))
> + return PTR_ERR(group);
> +
> + switch (type) {
> + case VFIO_IOMMU_NOTIFY:
> + ret = vfio_unregister_iommu_notifier(group, nb);
> + break;
> + default:
> + ret = -EINVAL;
> + }
> +
> vfio_group_put(group);
> return ret;
> }
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index 15ff042..6f3ff31 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -107,14 +107,24 @@ 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)
> -
> +typedef unsigned short vfio_notify_type_t;
> extern int vfio_register_notifier(struct device *dev,
> + vfio_notify_type_t type,
> + unsigned long *required_events,
> struct notifier_block *nb);
> -
> extern int vfio_unregister_notifier(struct device *dev,
> + vfio_notify_type_t type,
> struct notifier_block *nb);
>
> +/* each type has independent events */
> +enum vfio_notify_type {
> + VFIO_IOMMU_NOTIFY = (__force vfio_notify_type_t)0,
> +};
> +
> +/* events for VFIO_IOMMU_NOTIFY */
> +#define VFIO_IOMMU_NOTIFY_DMA_UNMAP BIT(0)
> +
> +
> /*
> * Sub-module helpers
> */
--
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