Commit f0b63680 authored by Sven Peter's avatar Sven Peter Committed by Joerg Roedel
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iommu/dart: Clear sid2group entry when a group is freed 



sid2groups keeps track of which stream id combinations belong to a
iommu_group to assign those correctly to devices.
When a iommu_group is freed a stale pointer will however remain in
sid2groups. This prevents devices with the same stream id combination
to ever be attached again (see below).
Fix that by creating a shadow copy of the stream id configuration
when a group is allocated for the first time and clear the sid2group
entry when that group is freed.

  # echo 1 >/sys/bus/pci/devices/0000\:03\:00.0/remove
  pci 0000:03:00.0: Removing from iommu group 1
  # echo 1 >/sys/bus/pci/rescan
  [...]
  pci 0000:03:00.0: BAR 0: assigned [mem 0x6a0000000-0x6a000ffff 64bit pref]
  pci 0000:03:00.0: BAR 2: assigned [mem 0x6a0010000-0x6a001ffff 64bit pref]
  pci 0000:03:00.0: BAR 6: assigned [mem 0x6c0100000-0x6c01007ff pref]
  tg3 0000:03:00.0: Failed to add to iommu group 1: -2
  [...]

Fixes: 46d1fb07 ("iommu/dart: Add DART iommu driver")
Reported-by: default avatarMarc Zyngier <maz@kernel.org>
Signed-off-by: default avatarSven Peter <sven@svenpeter.dev>
Tested-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210924134502.15589-1-sven@svenpeter.dev


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 0b482d0c

drivers/iommu/apple-dart.c

+35 −3
Original line number Diff line number Diff line
@@ -643,16 +643,34 @@ static int apple_dart_of_xlate(struct device *dev, struct of_phandle_args *args) 
	return -EINVAL;

}



static DEFINE_MUTEX(apple_dart_groups_lock);



static void apple_dart_release_group(void *iommu_data)

{

	int i, sid;

	struct apple_dart_stream_map *stream_map;

	struct apple_dart_master_cfg *group_master_cfg = iommu_data;



	mutex_lock(&apple_dart_groups_lock);



	for_each_stream_map(i, group_master_cfg, stream_map)

		for_each_set_bit(sid, &stream_map->sidmap, DART_MAX_STREAMS)

			stream_map->dart->sid2group[sid] = NULL;



	kfree(iommu_data);

	mutex_unlock(&apple_dart_groups_lock);

}



static struct iommu_group *apple_dart_device_group(struct device *dev)

{

	static DEFINE_MUTEX(lock);

	int i, sid;

	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);

	struct apple_dart_stream_map *stream_map;

	struct apple_dart_master_cfg *group_master_cfg;

	struct iommu_group *group = NULL;

	struct iommu_group *res = ERR_PTR(-EINVAL);



	mutex_lock(&lock);

	mutex_lock(&apple_dart_groups_lock);



	for_each_stream_map(i, cfg, stream_map) {

		for_each_set_bit(sid, &stream_map->sidmap, DART_MAX_STREAMS) {
@@ -680,6 +698,20 @@ static struct iommu_group *apple_dart_device_group(struct device *dev) 
#endif

		group = generic_device_group(dev);



	res = ERR_PTR(-ENOMEM);

	if (!group)

		goto out;



	group_master_cfg = kzalloc(sizeof(*group_master_cfg), GFP_KERNEL);

	if (!group_master_cfg) {

		iommu_group_put(group);

		goto out;

	}



	memcpy(group_master_cfg, cfg, sizeof(*group_master_cfg));

	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, DART_MAX_STREAMS)

			stream_map->dart->sid2group[sid] = group;
@@ -687,7 +719,7 @@ static struct iommu_group *apple_dart_device_group(struct device *dev) 
	res = group;



out:

	mutex_unlock(&lock);

	mutex_unlock(&apple_dart_groups_lock);

	return res;

}