Re: [PATCH v5 17/19] vfio: Add VFIO_DEVICE_AT[DE]TACH_IOMMUFD_PT

Jason Gunthorpe
2023-03-01T17:49:33Z

On Wed, Mar 01, 2023 at 02:04:00PM +0000, Liu, Yi L wrote:
> diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c
> index 2a13442add43..ed3ffe7ceb3f 100644
> --- a/drivers/vfio/group.c
> +++ b/drivers/vfio/group.c
> @@ -777,6 +777,11 @@ void vfio_device_group_unregister(struct vfio_device *device)
> mutex_unlock(&device->group->device_lock);
> }
>
> +bool vfio_device_group_uses_container(struct vfio_device *device)
> +{
> + return READ_ONCE(device->group->container);
> +}

As I said this should take in the vfio_device_file because as long as
a vfio_device_file exists then group->contianer is required to be stable.

> diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
> index 121a75fadceb..4b5b17e8aaa1 100644
> --- a/drivers/vfio/vfio_main.c
> +++ b/drivers/vfio/vfio_main.c
> @@ -422,9 +422,22 @@ static int vfio_device_first_open(struct vfio_device_file *df)
> if (!try_module_get(device->dev->driver->owner))
> return -ENODEV;
>
> + /*
> + * The handling here depends on what the user is using.
> + *
> + * If user uses iommufd in the group compat mode or the
> + * cdev path, call vfio_iommufd_bind().
> + *
> + * If user uses container in the group legacy mode, call
> + * vfio_device_group_use_iommu().
> + *
> + * If user doesn't use iommufd nor container, this is
> + * the noiommufd mode in the cdev path, nothing needs
> + * to be done here just go ahead to open device.
> + */
> if (iommufd)
> ret = vfio_iommufd_bind(device, iommufd);
> - else
> + else if (vfio_device_group_uses_container(device))
> ret = vfio_device_group_use_iommu(device);

But yes, this makes alot more sense..

Jason