From: Sven Peter <sven@xxxxxxxxxxxxx>
[ Upstream commit cf5c1c87c2391649e05e58ecc6dfc3dc5ebebc05 ]
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: f0b636804c7c ("iommu/dart: Clear sid2group entry when a group is freed")
Signed-off-by: Sven Peter <sven@xxxxxxxxxxxxx>
Reviewed-by: Eric Curtin <ecurtin@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230128113532.94651-1-sven@xxxxxxxxxxxxx
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/iommu/apple-dart.c | 51 ++++++++++++++++++++++++++++++++------
1 file changed, 44 insertions(+), 7 deletions(-)
diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
index 80e4436ee4de7..06ca73bddb5a5 100644
--- a/drivers/iommu/apple-dart.c
+++ b/drivers/iommu/apple-dart.c
@@ -689,6 +689,29 @@ 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;
@@ -730,14 +753,28 @@ 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);
- if (!group_master_cfg) {
- iommu_group_put(group);
- goto out;
- }
+ group_master_cfg = iommu_group_get_iommudata(group);
+ if (group_master_cfg) {
+ int ret;
- iommu_group_set_iommudata(group, group_master_cfg,
- apple_dart_release_group);
+ 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;
+ }
+
+ 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)
--
2.39.2
