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iommu/arm-smmu-v3: Pre-allocate a per-master invalidation array

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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 <jgg@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Pranjal Shrivastava <praan@google.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Nicolin Chen 2026-03-17 00:59:20 -07:00 committed by Will Deacon
parent 15a2a5645a
commit e3a56b37bf
2 changed files with 45 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
View File

@ -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;
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];
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 = fwspec->ids[i];
new_stream->id = sid;
new_stream->master = master;
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)

8
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
View File

@ -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;