Commit cf5c1c87 authored by Sven Peter's avatar Sven Peter Committed by Joerg Roedel
Browse files

iommu/dart: Fix apple_dart_device_group for PCI groups 



pci_device_group() can return an already existing IOMMU group if the PCI
device's pagetables have to be shared with another one due to bus
toplogy, isolation features and/or DMA alias quirks.
apple_dart_device_group() however assumes that the group has just been
created and overwrites its iommudata which will eventually lead to
apple_dart_release_group leaving stale entries in sid2group.
Fix that by merging the iommudata if the returned group already exists.

Fixes: f0b63680 ("iommu/dart: Clear sid2group entry when a group is freed")
Signed-off-by: default avatarSven Peter <sven@svenpeter.dev>
Reviewed-by: default avatarEric Curtin <ecurtin@redhat.com>
Link: https://lore.kernel.org/r/20230128113532.94651-1-sven@svenpeter.dev


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent d8bcc870

drivers/iommu/apple-dart.c

+44 −7
Original line number Diff line number Diff line
@@ -835,6 +835,29 @@ static void apple_dart_release_group(void *iommu_data) 
	mutex_unlock(&apple_dart_groups_lock);

}



static int apple_dart_merge_master_cfg(struct apple_dart_master_cfg *dst,

				       struct apple_dart_master_cfg *src)

{

	/*

	 * We know that this function is only called for groups returned from

	 * pci_device_group and that all Apple Silicon platforms never spread

	 * PCIe devices from the same bus across multiple DARTs such that we can

	 * just assume that both src and dst only have the same single DART.

	 */

	if (src->stream_maps[1].dart)

		return -EINVAL;

	if (dst->stream_maps[1].dart)

		return -EINVAL;

	if (src->stream_maps[0].dart != dst->stream_maps[0].dart)

		return -EINVAL;



	bitmap_or(dst->stream_maps[0].sidmap,

		  dst->stream_maps[0].sidmap,

		  src->stream_maps[0].sidmap,

		  dst->stream_maps[0].dart->num_streams);

	return 0;

}



static struct iommu_group *apple_dart_device_group(struct device *dev)

{

	int i, sid;
@@ -876,7 +899,20 @@ static struct iommu_group *apple_dart_device_group(struct device *dev) 
	if (!group)

		goto out;



	group_master_cfg = kmemdup(cfg, sizeof(*group_master_cfg), GFP_KERNEL);

	group_master_cfg = iommu_group_get_iommudata(group);

	if (group_master_cfg) {

		int ret;



		ret = apple_dart_merge_master_cfg(group_master_cfg, cfg);

		if (ret) {

			dev_err(dev, "Failed to merge DART IOMMU grups.\n");

			iommu_group_put(group);

			res = ERR_PTR(ret);

			goto out;

		}

	} else {

		group_master_cfg = kmemdup(cfg, sizeof(*group_master_cfg),

					   GFP_KERNEL);

		if (!group_master_cfg) {

			iommu_group_put(group);

			goto out;
@@ -884,6 +920,7 @@ static struct iommu_group *apple_dart_device_group(struct device *dev) 


		iommu_group_set_iommudata(group, group_master_cfg,

			apple_dart_release_group);

	}



	for_each_stream_map(i, cfg, stream_map)

		for_each_set_bit(sid, stream_map->sidmap, stream_map->dart->num_streams)