From: Nicolin Chen Date: Tue, 17 Mar 2026 07:59:20 +0000 (-0700) Subject: iommu/arm-smmu-v3: Pre-allocate a per-master invalidation array X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e3a56b37bf7546ecde4332d70a5bd092b9fe061b;p=thirdparty%2Fkernel%2Fstable.git iommu/arm-smmu-v3: Pre-allocate a per-master invalidation array When a master is attached from an old domain to a new domain, it needs to build an invalidation array to delete and add the array entries from/onto the invalidation arrays of those two domains, passed via the to_merge and to_unref arguments into arm_smmu_invs_merge/unref() respectively. Since the master->num_streams might differ across masters, a memory would have to be allocated when building an to_merge/to_unref array which might fail with -ENOMEM. On the other hand, an attachment to arm_smmu_blocked_domain must not fail so it's the best to avoid any memory allocation in that path. Pre-allocate a fixed size invalidation array for every master. This array will be used as a scratch to fill dynamically when building a to_merge or to_unref invs array. Sort fwspec->ids in an ascending order to fit to the arm_smmu_invs_merge() function. Co-developed-by: Jason Gunthorpe Signed-off-by: Jason Gunthorpe Reviewed-by: Jason Gunthorpe Reviewed-by: Pranjal Shrivastava Signed-off-by: Nicolin Chen Signed-off-by: Will Deacon --- diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c index 10050b1a6d94..8e651cf6b86e 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -3789,26 +3789,57 @@ static int arm_smmu_init_sid_strtab(struct arm_smmu_device *smmu, u32 sid) return 0; } +static int arm_smmu_stream_id_cmp(const void *_l, const void *_r) +{ + const typeof_member(struct arm_smmu_stream, id) *l = _l; + const typeof_member(struct arm_smmu_stream, id) *r = _r; + + return cmp_int(*l, *r); +} + static int arm_smmu_insert_master(struct arm_smmu_device *smmu, struct arm_smmu_master *master) { int i; int ret = 0; struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(master->dev); + bool ats_supported = dev_is_pci(master->dev) && + pci_ats_supported(to_pci_dev(master->dev)); master->streams = kzalloc_objs(*master->streams, fwspec->num_ids); if (!master->streams) return -ENOMEM; master->num_streams = fwspec->num_ids; - mutex_lock(&smmu->streams_mutex); + if (!ats_supported) { + /* Base case has 1 ASID entry or maximum 2 VMID entries */ + master->build_invs = arm_smmu_invs_alloc(2); + } else { + /* ATS case adds num_ids of entries, on top of the base case */ + master->build_invs = arm_smmu_invs_alloc(2 + fwspec->num_ids); + } + if (!master->build_invs) { + kfree(master->streams); + return -ENOMEM; + } + for (i = 0; i < fwspec->num_ids; i++) { struct arm_smmu_stream *new_stream = &master->streams[i]; - struct rb_node *existing; - u32 sid = fwspec->ids[i]; - new_stream->id = sid; + new_stream->id = fwspec->ids[i]; new_stream->master = master; + } + + /* Put the ids into order for sorted to_merge/to_unref arrays */ + sort_nonatomic(master->streams, master->num_streams, + sizeof(master->streams[0]), arm_smmu_stream_id_cmp, + NULL); + + mutex_lock(&smmu->streams_mutex); + for (i = 0; i < fwspec->num_ids; i++) { + struct arm_smmu_stream *new_stream = &master->streams[i]; + struct rb_node *existing; + u32 sid = new_stream->id; ret = arm_smmu_init_sid_strtab(smmu, sid); if (ret) @@ -3838,6 +3869,7 @@ static int arm_smmu_insert_master(struct arm_smmu_device *smmu, for (i--; i >= 0; i--) rb_erase(&master->streams[i].node, &smmu->streams); kfree(master->streams); + kfree(master->build_invs); } mutex_unlock(&smmu->streams_mutex); @@ -3859,6 +3891,7 @@ static void arm_smmu_remove_master(struct arm_smmu_master *master) mutex_unlock(&smmu->streams_mutex); kfree(master->streams); + kfree(master->build_invs); } static struct iommu_device *arm_smmu_probe_device(struct device *dev) diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h index ed8820f12ba3..5e0e5055af1e 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h @@ -928,6 +928,14 @@ struct arm_smmu_master { struct arm_smmu_device *smmu; struct device *dev; struct arm_smmu_stream *streams; + /* + * Scratch memory for a to_merge or to_unref array to build a per-domain + * invalidation array. It'll be pre-allocated with enough enries for all + * possible build scenarios. It can be used by only one caller at a time + * until the arm_smmu_invs_merge/unref() finishes. Must be locked by the + * iommu_group mutex. + */ + struct arm_smmu_invs *build_invs; struct arm_smmu_vmaster *vmaster; /* use smmu->streams_mutex */ /* Locked by the iommu core using the group mutex */ struct arm_smmu_ctx_desc_cfg cd_table;