Commit f38338cf authored May 11, 2020 by Thierry Reding Committed by Joerg Roedel May 13, 2020

iommu: Do not probe devices on IOMMU-less busses

The host1x bus implemented on Tegra SoCs is primarily an abstraction to
create logical device from multiple platform devices. Since the devices
in such a setup are typically hierarchical, DMA setup still needs to be
done so that DMA masks can be properly inherited, but we don't actually
want to attach the host1x logical devices to any IOMMU. The platform
devices that make up the logical device are responsible for memory bus
transactions, so it is them that will need to be attached to the IOMMU.

Add a check to __iommu_probe_device() that aborts IOMMU setup early for
busses that don't have the IOMMU operations pointer set since they will
cause a crash otherwise.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20200511161000.3853342-1-thierry.reding@gmail.com

Signed-off-by: Joerg Roedel <jroedel@suse.de>

parent cfcccbe8

drivers/iommu/iommu.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -195,6 +195,9 @@ static int __iommu_probe_device(struct device dev, struct list_head group_list
		struct iommu_group *group;
		int ret;

		if (!ops)
		return -ENODEV;

		if (!dev_iommu_get(dev))
		return -ENOMEM;

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