Re: [PATCH v2 1/2] iommu: add support for drivers that manage iommu explicitly

From: Joerg Roedel
Date: Tue Sep 10 2019 - 04:14:21 EST

On Fri, Sep 06, 2019 at 02:44:01PM -0700, Rob Clark wrote:
> @@ -674,7 +674,7 @@ int iommu_group_add_device(struct iommu_group *group, struct device *dev)
> mutex_lock(&group->mutex);
> list_add_tail(&device->list, &group->devices);
> - if (group->domain)
> + if (group->domain && !(dev->driver && dev->driver->driver_manages_iommu))

Hmm, this code usually runs at enumeration time when no driver is
attached to the device. Actually it would be pretty dangerous when this
code runs while a driver is attached to the device. How does that change
make things work for you?