From: Sven Peter sven@svenpeter.dev
[ 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@svenpeter.dev Reviewed-by: Eric Curtin ecurtin@redhat.com Link: https://lore.kernel.org/r/20230128113532.94651-1-sven@svenpeter.dev Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- 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)