iommu/arm-smmu-v3: Allow setting a S1 domain to a PASID

The SVA cleanup made the SSID logic entirely general so all we need to do
is call it with the correct cd table entry for a S1 domain.

This is slightly tricky because of the ASID and how the locking works, the
simple fix is to just update the ASID once we get the right locks.

Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/14-v9-5cd718286059+79186-smmuv3_newapi_p2b_jgg@nvidia.com
Signed-off-by: Will Deacon <will@kernel.org>

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c

@@ -2798,6 +2798,36 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	return 0;
 }
 
+static int arm_smmu_s1_set_dev_pasid(struct iommu_domain *domain,
+				      struct device *dev, ioasid_t id)
+{
+	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+	struct arm_smmu_device *smmu = master->smmu;
+	struct arm_smmu_cd target_cd;
+	int ret = 0;
+
+	mutex_lock(&smmu_domain->init_mutex);
+	if (!smmu_domain->smmu)
+		ret = arm_smmu_domain_finalise(smmu_domain, smmu);
+	else if (smmu_domain->smmu != smmu)
+		ret = -EINVAL;
+	mutex_unlock(&smmu_domain->init_mutex);
+	if (ret)
+		return ret;
+
+	if (smmu_domain->stage != ARM_SMMU_DOMAIN_S1)
+		return -EINVAL;
+
+	/*
+	 * We can read cd.asid outside the lock because arm_smmu_set_pasid()
+	 * will fix it
+	 */
+	arm_smmu_make_s1_cd(&target_cd, master, smmu_domain);
+	return arm_smmu_set_pasid(master, to_smmu_domain(domain), id,
+				  &target_cd);
+}
+
 static void arm_smmu_update_ste(struct arm_smmu_master *master,
 				struct iommu_domain *sid_domain,
 				bool ats_enabled)
@@ -2825,7 +2855,7 @@ static void arm_smmu_update_ste(struct arm_smmu_master *master,
 
 int arm_smmu_set_pasid(struct arm_smmu_master *master,
 		       struct arm_smmu_domain *smmu_domain, ioasid_t pasid,
-		       const struct arm_smmu_cd *cd)
+		       struct arm_smmu_cd *cd)
 {
 	struct iommu_domain *sid_domain = iommu_get_domain_for_dev(master->dev);
 	struct arm_smmu_attach_state state = {
@@ -2858,6 +2888,14 @@ int arm_smmu_set_pasid(struct arm_smmu_master *master,
 	if (ret)
 		goto out_unlock;
 
+	/*
+	 * We don't want to obtain to the asid_lock too early, so fix up the
+	 * caller set ASID under the lock in case it changed.
+	 */
+	cd->data[0] &= ~cpu_to_le64(CTXDESC_CD_0_ASID);
+	cd->data[0] |= cpu_to_le64(
+		FIELD_PREP(CTXDESC_CD_0_ASID, smmu_domain->cd.asid));
+
 	arm_smmu_write_cd_entry(master, pasid, cdptr, cd);
 	arm_smmu_update_ste(master, sid_domain, state.ats_enabled);
 
@@ -3376,6 +3414,7 @@ static struct iommu_ops arm_smmu_ops = {
 	.owner			= THIS_MODULE,
 	.default_domain_ops = &(const struct iommu_domain_ops) {
 		.attach_dev		= arm_smmu_attach_dev,
+		.set_dev_pasid		= arm_smmu_s1_set_dev_pasid,
 		.map_pages		= arm_smmu_map_pages,
 		.unmap_pages		= arm_smmu_unmap_pages,
 		.flush_iotlb_all	= arm_smmu_flush_iotlb_all,

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h

@@ -801,7 +801,7 @@ void arm_smmu_write_cd_entry(struct arm_smmu_master *master, int ssid,
 
 int arm_smmu_set_pasid(struct arm_smmu_master *master,
 		       struct arm_smmu_domain *smmu_domain, ioasid_t pasid,
-		       const struct arm_smmu_cd *cd);
+		       struct arm_smmu_cd *cd);
 
 void arm_smmu_tlb_inv_asid(struct arm_smmu_device *smmu, u16 asid);
 void arm_smmu_tlb_inv_range_asid(unsigned long iova, size_t size, int asid,