iommu/arm-smmu-v3: Consolidate the STE generation for abort/bypass

This allows writing the flow of arm_smmu_write_strtab_ent() around abort
and bypass domains more naturally.

Note that the core code no longer supplies NULL domains, though there is
still a flow in the driver that end up in arm_smmu_write_strtab_ent() with
NULL. A later patch will remove it.

Remove the duplicate calculation of the STE in arm_smmu_init_bypass_stes()
and remove the force parameter. arm_smmu_rmr_install_bypass_ste() can now
simply invoke arm_smmu_make_bypass_ste() directly.

Rename arm_smmu_init_bypass_stes() to arm_smmu_init_initial_stes() to
better reflect its purpose.
Reviewed-by: Michael Shavit <mshavit@google.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Mostafa Saleh <smostafa@google.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Moritz Fischer <moritzf@google.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/2-v6-96275f25c39d+2d4-smmuv3_newapi_p1_jgg@nvidia.comSigned-off-by: Will Deacon <will@kernel.org>

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

@@ -1447,6 +1447,24 @@ static void arm_smmu_sync_ste_for_sid(struct arm_smmu_device *smmu, u32 sid)
 	arm_smmu_cmdq_issue_cmd_with_sync(smmu, &cmd);
 }
 
+static void arm_smmu_make_abort_ste(struct arm_smmu_ste *target)
+{
+	memset(target, 0, sizeof(*target));
+	target->data[0] = cpu_to_le64(
+		STRTAB_STE_0_V |
+		FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_ABORT));
+}
+
+static void arm_smmu_make_bypass_ste(struct arm_smmu_ste *target)
+{
+	memset(target, 0, sizeof(*target));
+	target->data[0] = cpu_to_le64(
+		STRTAB_STE_0_V |
+		FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_BYPASS));
+	target->data[1] = cpu_to_le64(
+		FIELD_PREP(STRTAB_STE_1_SHCFG, STRTAB_STE_1_SHCFG_INCOMING));
+}
+
 static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
 				      struct arm_smmu_ste *dst)
 {
@@ -1457,37 +1475,31 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
 	struct arm_smmu_domain *smmu_domain = master->domain;
 	struct arm_smmu_ste target = {};
 
-	if (smmu_domain) {
-		switch (smmu_domain->stage) {
-		case ARM_SMMU_DOMAIN_S1:
-			cd_table = &master->cd_table;
-			break;
-		case ARM_SMMU_DOMAIN_S2:
-			s2_cfg = &smmu_domain->s2_cfg;
-			break;
-		default:
-			break;
-		}
-	}
-
-	/* Nuke the existing STE_0 value, as we're going to rewrite it */
-	val = STRTAB_STE_0_V;
-
-	/* Bypass/fault */
-	if (!smmu_domain || !(cd_table || s2_cfg)) {
-		if (!smmu_domain && disable_bypass)
-			val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_ABORT);
+	if (!smmu_domain) {
+		if (disable_bypass)
+			arm_smmu_make_abort_ste(&target);
 		else
-			val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_BYPASS);
+			arm_smmu_make_bypass_ste(&target);
+		arm_smmu_write_ste(master, sid, dst, &target);
+		return;
+	}
 
-		target.data[0] = cpu_to_le64(val);
-		target.data[1] = cpu_to_le64(FIELD_PREP(STRTAB_STE_1_SHCFG,
-						STRTAB_STE_1_SHCFG_INCOMING));
-		target.data[2] = 0; /* Nuke the VMID */
+	switch (smmu_domain->stage) {
+	case ARM_SMMU_DOMAIN_S1:
+		cd_table = &master->cd_table;
+		break;
+	case ARM_SMMU_DOMAIN_S2:
+		s2_cfg = &smmu_domain->s2_cfg;
+		break;
+	case ARM_SMMU_DOMAIN_BYPASS:
+		arm_smmu_make_bypass_ste(&target);
 		arm_smmu_write_ste(master, sid, dst, &target);
 		return;
 	}
 
+	/* Nuke the existing STE_0 value, as we're going to rewrite it */
+	val = STRTAB_STE_0_V;
+
 	if (cd_table) {
 		u64 strw = smmu->features & ARM_SMMU_FEAT_E2H ?
 			STRTAB_STE_1_STRW_EL2 : STRTAB_STE_1_STRW_NSEL1;
@@ -1534,22 +1546,20 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
 	arm_smmu_write_ste(master, sid, dst, &target);
 }
 
-static void arm_smmu_init_bypass_stes(struct arm_smmu_ste *strtab,
-				      unsigned int nent, bool force)
+/*
+ * This can safely directly manipulate the STE memory without a sync sequence
+ * because the STE table has not been installed in the SMMU yet.
+ */
+static void arm_smmu_init_initial_stes(struct arm_smmu_ste *strtab,
+				       unsigned int nent)
 {
 	unsigned int i;
-	u64 val = STRTAB_STE_0_V;
-
-	if (disable_bypass && !force)
-		val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_ABORT);
-	else
-		val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_BYPASS);
 
 	for (i = 0; i < nent; ++i) {
-		strtab->data[0] = cpu_to_le64(val);
-		strtab->data[1] = cpu_to_le64(FIELD_PREP(
-			STRTAB_STE_1_SHCFG, STRTAB_STE_1_SHCFG_INCOMING));
-		strtab->data[2] = 0;
+		if (disable_bypass)
+			arm_smmu_make_abort_ste(strtab);
+		else
+			arm_smmu_make_bypass_ste(strtab);
 		strtab++;
 	}
 }
@@ -1577,7 +1587,7 @@ static int arm_smmu_init_l2_strtab(struct arm_smmu_device *smmu, u32 sid)
 		return -ENOMEM;
 	}
 
-	arm_smmu_init_bypass_stes(desc->l2ptr, 1 << STRTAB_SPLIT, false);
+	arm_smmu_init_initial_stes(desc->l2ptr, 1 << STRTAB_SPLIT);
 	arm_smmu_write_strtab_l1_desc(strtab, desc);
 	return 0;
 }
@@ -3196,7 +3206,7 @@ static int arm_smmu_init_strtab_linear(struct arm_smmu_device *smmu)
 	reg |= FIELD_PREP(STRTAB_BASE_CFG_LOG2SIZE, smmu->sid_bits);
 	cfg->strtab_base_cfg = reg;
 
-	arm_smmu_init_bypass_stes(strtab, cfg->num_l1_ents, false);
+	arm_smmu_init_initial_stes(strtab, cfg->num_l1_ents);
 	return 0;
 }
 
@@ -3907,7 +3917,6 @@ static void arm_smmu_rmr_install_bypass_ste(struct arm_smmu_device *smmu)
 	iort_get_rmr_sids(dev_fwnode(smmu->dev), &rmr_list);
 
 	list_for_each_entry(e, &rmr_list, list) {
-		struct arm_smmu_ste *step;
 		struct iommu_iort_rmr_data *rmr;
 		int ret, i;
 
@@ -3920,8 +3929,12 @@ static void arm_smmu_rmr_install_bypass_ste(struct arm_smmu_device *smmu)
 				continue;
 			}
 
-			step = arm_smmu_get_step_for_sid(smmu, rmr->sids[i]);
-			arm_smmu_init_bypass_stes(step, 1, true);
+			/*
+			 * STE table is not programmed to HW, see
+			 * arm_smmu_initial_bypass_stes()
+			 */
+			arm_smmu_make_bypass_ste(
+				arm_smmu_get_step_for_sid(smmu, rmr->sids[i]));
 		}
 	}