[v5,08/13] iommu/arm-smmu-v3: Propagate ssid_bits

Commit Message

Jean-Philippe Brucker Jan. 15, 2020, 12:52 p.m. UTC

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 <[e-mail]>
Reviewed-by: Eric Auger <[e-mail]>
Reviewed-by: Jonathan Cameron <[e-mail]>
Signed-off-by: Jean-Philippe Brucker <[e-mail]>
---
 drivers/iommu/arm-smmu-v3.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

Patch

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 6ab0e93518f6..7b7dea596f60 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -2277,6 +2277,7 @@  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;
@@ -2288,6 +2289,8 @@  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;
@@ -2304,6 +2307,7 @@  static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 }
 
 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;
@@ -2320,7 +2324,8 @@  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;
@@ -2328,6 +2333,7 @@  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;
@@ -2382,7 +2388,7 @@  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;
@@ -2535,7 +2541,7 @@  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;
@@ -2547,6 +2553,13 @@  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;