iommu/arm-smmu-v3: Propagate ssid_bits

Now that we support substream IDs, initialize s1cdmax with the number of
SSID bits supported by a master and the SMMU.

Context descriptor tables are allocated once for the first master
attached to a domain. Therefore attaching multiple devices with
different SSID sizes is tricky, and we currently don't support it.

As a future improvement it would be nice to at least support attaching a
SSID-capable device to a domain that isn't using SSID, by reallocating
the SSID table. This would allow supporting a SSID-capable device that
is in the same IOMMU group as a bridge, for example. Varying SSID size
is less of a concern, since the PCIe specification "highly recommends"
that devices supporting PASID implement all 20 bits of it.

Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index b0e63de9009ef46a8a9050b4720d7d8bcbd57d97..88a48256c11e09db7e83a4f08af6dc1f5bd33037 100644 (file)
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -2250,6 +2250,7 @@ static void arm_smmu_domain_free(struct iommu_domain *domain)
 }
 
 static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
+                                      struct arm_smmu_master *master,
                                       struct io_pgtable_cfg *pgtbl_cfg)
 {
        int ret;
@@ -2262,6 +2263,8 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
        if (asid < 0)
                return asid;
 
+       cfg->s1cdmax = master->ssid_bits;
+
        ret = arm_smmu_alloc_cd_tables(smmu_domain);
        if (ret)
                goto out_free_asid;
@@ -2284,6 +2287,7 @@ out_free_asid:
 }
 
 static int arm_smmu_domain_finalise_s2(struct arm_smmu_domain *smmu_domain,
+                                      struct arm_smmu_master *master,
                                       struct io_pgtable_cfg *pgtbl_cfg)
 {
        int vmid;
@@ -2308,7 +2312,8 @@ static int arm_smmu_domain_finalise_s2(struct arm_smmu_domain *smmu_domain,
        return 0;
 }
 
-static int arm_smmu_domain_finalise(struct iommu_domain *domain)
+static int arm_smmu_domain_finalise(struct iommu_domain *domain,
+                                   struct arm_smmu_master *master)
 {
        int ret;
        unsigned long ias, oas;
@@ -2316,6 +2321,7 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain)
        struct io_pgtable_cfg pgtbl_cfg;
        struct io_pgtable_ops *pgtbl_ops;
        int (*finalise_stage_fn)(struct arm_smmu_domain *,
+                                struct arm_smmu_master *,
                                 struct io_pgtable_cfg *);
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
        struct arm_smmu_device *smmu = smmu_domain->smmu;
@@ -2370,7 +2376,7 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain)
        domain->geometry.aperture_end = (1UL << pgtbl_cfg.ias) - 1;
        domain->geometry.force_aperture = true;
 
-       ret = finalise_stage_fn(smmu_domain, &pgtbl_cfg);
+       ret = finalise_stage_fn(smmu_domain, master, &pgtbl_cfg);
        if (ret < 0) {
                free_io_pgtable_ops(pgtbl_ops);
                return ret;
@@ -2523,7 +2529,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 
        if (!smmu_domain->smmu) {
                smmu_domain->smmu = smmu;
-               ret = arm_smmu_domain_finalise(domain);
+               ret = arm_smmu_domain_finalise(domain, master);
                if (ret) {
                        smmu_domain->smmu = NULL;
                        goto out_unlock;
@@ -2535,6 +2541,13 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
                        dev_name(smmu->dev));
                ret = -ENXIO;
                goto out_unlock;
+       } else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
+                  master->ssid_bits != smmu_domain->s1_cfg.s1cdmax) {
+               dev_err(dev,
+                       "cannot attach to incompatible domain (%u SSID bits != %u)\n",
+                       smmu_domain->s1_cfg.s1cdmax, master->ssid_bits);
+               ret = -EINVAL;
+               goto out_unlock;
        }
 
        master->domain = smmu_domain;