On 1/29/2021 4:57 PM, Alex Williamson wrote:
> On Fri, 29 Jan 2021 08:54:10 -0800
> Steve Sistare <steven.sistare@xxxxxxxxxx> wrote:
>
>> Define a vfio_iommu_driver_ops notify callback, for sending events to
>> the driver. Drivers are not required to provide the callback, and
>> may ignore any events. The handling of events is driver specific.
>>
>> Define the CONTAINER_CLOSE event, called when the container's file
>> descriptor is closed. This event signifies that no further state changes
>> will occur via container ioctl's.
>>
>> Signed-off-by: Steve Sistare <steven.sistare@xxxxxxxxxx>
>> ---
>> drivers/vfio/vfio.c | 5 +++++
>> include/linux/vfio.h | 5 +++++
>> 2 files changed, 10 insertions(+)
>>
>> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
>> index 262ab0e..99458fc 100644
>> --- a/drivers/vfio/vfio.c
>> +++ b/drivers/vfio/vfio.c
>> @@ -1220,6 +1220,11 @@ static int vfio_fops_open(struct inode *inode, struct file *filep)
>> static int vfio_fops_release(struct inode *inode, struct file *filep)
>> {
>> struct vfio_container *container = filep->private_data;
>> + struct vfio_iommu_driver *driver = container->iommu_driver;
>> +
>> + if (driver && driver->ops->notify)
>> + driver->ops->notify(container->iommu_data,
>> + VFIO_DRIVER_NOTIFY_CONTAINER_CLOSE, NULL);
>>
>> filep->private_data = NULL;
>>
>> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
>> index 38d3c6a..9642579 100644
>> --- a/include/linux/vfio.h
>> +++ b/include/linux/vfio.h
>> @@ -57,6 +57,9 @@ extern int vfio_add_group_dev(struct device *dev,
>> extern void vfio_device_put(struct vfio_device *device);
>> extern void *vfio_device_data(struct vfio_device *device);
>>
>> +/* events for the backend driver notify callback */
>> +#define VFIO_DRIVER_NOTIFY_CONTAINER_CLOSE 1
>
> We should use an enum for type checking.
Agreed.
I see you changed the value to 0. Do you want to reserve 0 for invalid-event?
(I know, this is internal and can be changed). Your call.
>> +
>> /**
>> * struct vfio_iommu_driver_ops - VFIO IOMMU driver callbacks
>> */
>> @@ -90,6 +93,8 @@ struct vfio_iommu_driver_ops {
>> struct notifier_block *nb);
>> int (*dma_rw)(void *iommu_data, dma_addr_t user_iova,
>> void *data, size_t count, bool write);
>> + void (*notify)(void *iommu_data, unsigned int event,
>> + void *data);
>
> I'm not sure why we're pre-enabling this 3rd arg, do you have some
> short term usage in mind that we can't easily add on demand later?
> This is an internal API, not one we need to keep stable. Thanks,
No short term need, just seems sensible for an event callback. I was mimic'ing the
signature of the callback for vfio_register_notifier. Your call.
- Steve
>
> Alex
>
>> };
>>
>> extern int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops *ops);
>
