iommu/arm-smmu-v3: Move ctx_desc out of s1_cfg

arm_smmu_s1_cfg (and by extension arm_smmu_domain) owns both a CD table
and the CD inserted into that table's non-pasid CD entry. This limits
arm_smmu_domain's ability to represent non-pasid domains, where multiple
domains need to be inserted into a common CD table. Rather than describing
an STE entry (which may have multiple domains installed into it with
PASID), a domain should describe a single CD entry instead. This is
precisely the role of arm_smmu_ctx_desc. A subsequent commit will also
move the CD table outside of arm_smmu_domain.
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Michael Shavit <mshavit@google.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Link: https://lore.kernel.org/r/20230915211705.v8.1.I67ab103c18d882aedc8a08985af1fba70bca084e@changeidSigned-off-by: Will Deacon <will@kernel.org>

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

@@ -62,7 +62,7 @@ arm_smmu_share_asid(struct mm_struct *mm, u16 asid)
 		return cd;
 	}
 
-	smmu_domain = container_of(cd, struct arm_smmu_domain, s1_cfg.cd);
+	smmu_domain = container_of(cd, struct arm_smmu_domain, cd);
 	smmu = smmu_domain->smmu;
 
 	ret = xa_alloc(&arm_smmu_asid_xa, &new_asid, cd,

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

@@ -1869,7 +1869,7 @@ static void arm_smmu_tlb_inv_context(void *cookie)
 	 * careful, 007.
 	 */
 	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
-		arm_smmu_tlb_inv_asid(smmu, smmu_domain->s1_cfg.cd.asid);
+		arm_smmu_tlb_inv_asid(smmu, smmu_domain->cd.asid);
 	} else {
 		cmd.opcode	= CMDQ_OP_TLBI_S12_VMALL;
 		cmd.tlbi.vmid	= smmu_domain->s2_cfg.vmid;
@@ -1962,7 +1962,7 @@ static void arm_smmu_tlb_inv_range_domain(unsigned long iova, size_t size,
 	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
 		cmd.opcode	= smmu_domain->smmu->features & ARM_SMMU_FEAT_E2H ?
 				  CMDQ_OP_TLBI_EL2_VA : CMDQ_OP_TLBI_NH_VA;
-		cmd.tlbi.asid	= smmu_domain->s1_cfg.cd.asid;
+		cmd.tlbi.asid	= smmu_domain->cd.asid;
 	} else {
 		cmd.opcode	= CMDQ_OP_TLBI_S2_IPA;
 		cmd.tlbi.vmid	= smmu_domain->s2_cfg.vmid;
@@ -2075,7 +2075,7 @@ static void arm_smmu_domain_free(struct iommu_domain *domain)
 		mutex_lock(&arm_smmu_asid_lock);
 		if (cfg->cdcfg.cdtab)
 			arm_smmu_free_cd_tables(smmu_domain);
-		arm_smmu_free_asid(&cfg->cd);
+		arm_smmu_free_asid(&smmu_domain->cd);
 		mutex_unlock(&arm_smmu_asid_lock);
 	} else {
 		struct arm_smmu_s2_cfg *cfg = &smmu_domain->s2_cfg;
@@ -2094,13 +2094,14 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 	u32 asid;
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
 	struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
+	struct arm_smmu_ctx_desc *cd = &smmu_domain->cd;
 	typeof(&pgtbl_cfg->arm_lpae_s1_cfg.tcr) tcr = &pgtbl_cfg->arm_lpae_s1_cfg.tcr;
 
-	refcount_set(&cfg->cd.refs, 1);
+	refcount_set(&cd->refs, 1);
 
 	/* Prevent SVA from modifying the ASID until it is written to the CD */
 	mutex_lock(&arm_smmu_asid_lock);
-	ret = xa_alloc(&arm_smmu_asid_xa, &asid, &cfg->cd,
+	ret = xa_alloc(&arm_smmu_asid_xa, &asid, cd,
 		       XA_LIMIT(1, (1 << smmu->asid_bits) - 1), GFP_KERNEL);
 	if (ret)
 		goto out_unlock;
@@ -2113,23 +2114,23 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 	if (ret)
 		goto out_free_asid;
 
-	cfg->cd.asid	= (u16)asid;
-	cfg->cd.ttbr	= pgtbl_cfg->arm_lpae_s1_cfg.ttbr;
-	cfg->cd.tcr	= FIELD_PREP(CTXDESC_CD_0_TCR_T0SZ, tcr->tsz) |
+	cd->asid	= (u16)asid;
+	cd->ttbr	= pgtbl_cfg->arm_lpae_s1_cfg.ttbr;
+	cd->tcr		= FIELD_PREP(CTXDESC_CD_0_TCR_T0SZ, tcr->tsz) |
 			  FIELD_PREP(CTXDESC_CD_0_TCR_TG0, tcr->tg) |
 			  FIELD_PREP(CTXDESC_CD_0_TCR_IRGN0, tcr->irgn) |
 			  FIELD_PREP(CTXDESC_CD_0_TCR_ORGN0, tcr->orgn) |
 			  FIELD_PREP(CTXDESC_CD_0_TCR_SH0, tcr->sh) |
 			  FIELD_PREP(CTXDESC_CD_0_TCR_IPS, tcr->ips) |
 			  CTXDESC_CD_0_TCR_EPD1 | CTXDESC_CD_0_AA64;
-	cfg->cd.mair	= pgtbl_cfg->arm_lpae_s1_cfg.mair;
+	cd->mair	= pgtbl_cfg->arm_lpae_s1_cfg.mair;
 
 	/*
 	 * Note that this will end up calling arm_smmu_sync_cd() before
 	 * the master has been added to the devices list for this domain.
 	 * This isn't an issue because the STE hasn't been installed yet.
 	 */
-	ret = arm_smmu_write_ctx_desc(smmu_domain, IOMMU_NO_PASID, &cfg->cd);
+	ret = arm_smmu_write_ctx_desc(smmu_domain, IOMMU_NO_PASID, cd);
 	if (ret)
 		goto out_free_cd_tables;
 
@@ -2139,7 +2140,7 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 out_free_cd_tables:
 	arm_smmu_free_cd_tables(smmu_domain);
 out_free_asid:
-	arm_smmu_free_asid(&cfg->cd);
+	arm_smmu_free_asid(cd);
 out_unlock:
 	mutex_unlock(&arm_smmu_asid_lock);
 	return ret;

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

@@ -599,7 +599,6 @@ struct arm_smmu_ctx_desc_cfg {
 
 struct arm_smmu_s1_cfg {
 	struct arm_smmu_ctx_desc_cfg	cdcfg;
-	struct arm_smmu_ctx_desc	cd;
 	u8				s1fmt;
 	u8				s1cdmax;
 };
@@ -724,7 +723,10 @@ struct arm_smmu_domain {
 
 	enum arm_smmu_domain_stage	stage;
 	union {
-		struct arm_smmu_s1_cfg	s1_cfg;
+		struct {
+		struct arm_smmu_ctx_desc	cd;
+		struct arm_smmu_s1_cfg		s1_cfg;
+		};
 		struct arm_smmu_s2_cfg	s2_cfg;
 	};