On 11/19/2016 01:55 AM, Alex Williamson wrote:
> 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()
>
Will do that in next version.
>> +
>> + 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
> ^
>
Ough, sorry .. will fix it in next version.
--
Thanks,
Jike
>> + }
>> +
>> + 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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