Re: [PATCH v7 14/23] iommu/smmuv3: Implement cache_invalidate

From: Robin Murphy
Date: Wed May 08 2019 - 11:02:24 EST


On 08/04/2019 13:19, Eric Auger wrote:
Implement domain-selective and page-selective IOTLB invalidations.

Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>

---
v6 -> v7
- check the uapi version

v3 -> v4:
- adapt to changes in the uapi
- add support for leaf parameter
- do not use arm_smmu_tlb_inv_range_nosync or arm_smmu_tlb_inv_context
anymore

v2 -> v3:
- replace __arm_smmu_tlb_sync by arm_smmu_cmdq_issue_sync

v1 -> v2:
- properly pass the asid
---
drivers/iommu/arm-smmu-v3.c | 60 +++++++++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 1486baf53425..4366921d8318 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -2326,6 +2326,65 @@ static void arm_smmu_detach_pasid_table(struct iommu_domain *domain)
mutex_unlock(&smmu_domain->init_mutex);
}
+static int
+arm_smmu_cache_invalidate(struct iommu_domain *domain, struct device *dev,
+ struct iommu_cache_invalidate_info *inv_info)
+{
+ struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+ struct arm_smmu_device *smmu = smmu_domain->smmu;
+
+ if (smmu_domain->stage != ARM_SMMU_DOMAIN_NESTED)
+ return -EINVAL;
+
+ if (!smmu)
+ return -EINVAL;
+
+ if (inv_info->version != IOMMU_CACHE_INVALIDATE_INFO_VERSION_1)
+ return -EINVAL;
+
+ if (inv_info->cache & IOMMU_CACHE_INV_TYPE_IOTLB) {
+ if (inv_info->granularity == IOMMU_INV_GRANU_PASID) {
+ struct arm_smmu_cmdq_ent cmd = {
+ .opcode = CMDQ_OP_TLBI_NH_ASID,
+ .tlbi = {
+ .vmid = smmu_domain->s2_cfg.vmid,
+ .asid = inv_info->pasid,
+ },
+ };
+
+ arm_smmu_cmdq_issue_cmd(smmu, &cmd);
+ arm_smmu_cmdq_issue_sync(smmu);

I'd much rather make arm_smmu_tlb_inv_context() understand nested domains than open-code commands all over the place.

+
+ } else if (inv_info->granularity == IOMMU_INV_GRANU_ADDR) {
+ struct iommu_inv_addr_info *info = &inv_info->addr_info;
+ size_t size = info->nb_granules * info->granule_size;
+ bool leaf = info->flags & IOMMU_INV_ADDR_FLAGS_LEAF;
+ struct arm_smmu_cmdq_ent cmd = {
+ .opcode = CMDQ_OP_TLBI_NH_VA,
+ .tlbi = {
+ .addr = info->addr,
+ .vmid = smmu_domain->s2_cfg.vmid,
+ .asid = info->pasid,
+ .leaf = leaf,
+ },
+ };
+
+ do {
+ arm_smmu_cmdq_issue_cmd(smmu, &cmd);
+ cmd.tlbi.addr += info->granule_size;
+ } while (size -= info->granule_size);
+ arm_smmu_cmdq_issue_sync(smmu);

An this in particular I would really like to go all the way through io_pgtable_tlb_add_flush()/io_pgtable_sync() if at all possible. Hooking up range-based invalidations is going to be a massive headache if the abstraction isn't solid.

Robin.

+ } else {
+ return -EINVAL;
+ }
+ }
+ if (inv_info->cache & IOMMU_CACHE_INV_TYPE_PASID ||
+ inv_info->cache & IOMMU_CACHE_INV_TYPE_DEV_IOTLB) {
+ return -ENOENT;
+ }
+ return 0;
+}
+
static struct iommu_ops arm_smmu_ops = {
.capable = arm_smmu_capable,
.domain_alloc = arm_smmu_domain_alloc,
@@ -2346,6 +2405,7 @@ static struct iommu_ops arm_smmu_ops = {
.put_resv_regions = arm_smmu_put_resv_regions,
.attach_pasid_table = arm_smmu_attach_pasid_table,
.detach_pasid_table = arm_smmu_detach_pasid_table,
+ .cache_invalidate = arm_smmu_cache_invalidate,
.pgsize_bitmap = -1UL, /* Restricted during device attach */
};