Commit e7f85dfb authored by Jason Gunthorpe's avatar Jason Gunthorpe Committed by Joerg Roedel
Browse files

iommu: Fix iommu_probe_device() to attach the right domain 



The general invariant is that all devices in an iommu_group are attached
to group->domain. We missed some cases here where an owned group would not
get the device attached.

Rework this logic so it follows the default domain flow of the
bus_iommu_probe() - call iommu_alloc_default_domain(), then use
__iommu_group_set_domain_internal() to set up all the devices.

Finally always attach the device to the current domain if it is already
set.

This is an unlikely functional issue as iommufd uses iommu_attach_group().
It is possible to hot plug in a new group member, add a vfio driver to it
and then hot add it to an existing iommufd. In this case it is required
that the core code set the iommu_domain properly since iommufd won't call
iommu_attach_group() again.

Reviewed-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Tested-by: default avatarHeiko Stuebner <heiko@sntech.de>
Tested-by: default avatarNiklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/9-v5-1b99ae392328+44574-iommu_err_unwind_jgg@nvidia.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 2f74198a

drivers/iommu/iommu.c

+24 −20
Original line number Diff line number Diff line
@@ -421,27 +421,31 @@ int iommu_probe_device(struct device *dev) 
		goto err_release;

	}



	mutex_lock(&group->mutex);



	if (group->domain) {

		ret = __iommu_device_set_domain(group, dev, group->domain, 0);

	} else if (!group->default_domain) {

		/*

		 * Try to allocate a default domain - needs support from the

		 * IOMMU driver. There are still some drivers which don't

		 * support default domains, so the return value is not yet

		 * checked.

		 */

	mutex_lock(&group->mutex);

		iommu_alloc_default_domain(group, dev);

		group->domain = NULL;

		if (group->default_domain)

			ret = __iommu_group_set_domain(group,

						       group->default_domain);



		/*

	 * If device joined an existing group which has been claimed, don't

	 * attach the default domain.

		 * We assume that the iommu driver starts up the device in

		 * 'set_platform_dma_ops' mode if it does not support default

		 * domains.

		 */

	if (group->default_domain && !group->owner) {

		ret = __iommu_device_set_domain(group, dev, group->domain, 0);

		if (ret) {

			mutex_unlock(&group->mutex);

			iommu_group_put(group);

			goto err_release;

		}

	}

	if (ret)

		goto err_unlock;



	iommu_create_device_direct_mappings(group, dev);
@@ -454,6 +458,9 @@ int iommu_probe_device(struct device *dev) 


	return 0;



err_unlock:

	mutex_unlock(&group->mutex);

	iommu_group_put(group);

err_release:

	iommu_release_device(dev);
@@ -1665,9 +1672,6 @@ static int iommu_alloc_default_domain(struct iommu_group *group, 
{

	unsigned int type;



	if (group->default_domain)

		return 0;



	type = iommu_get_def_domain_type(dev) ? : iommu_def_domain_type;



	return iommu_group_alloc_default_domain(dev->bus, group, type);