iommu/arm-smmu-v3: Thread SSID through the arm_smmu_attach_*() interface

Allow creating and managing arm_smmu_mater_domain's with a non-zero SSID
through the arm_smmu_attach_*() family of functions. This triggers ATC
invalidation for the correct SSID in PASID cases and tracks the
per-attachment SSID in the struct arm_smmu_master_domain.

Generalize arm_smmu_attach_remove() to be able to remove SSID's as well by
ensuring the ATC for the PASID is flushed properly.
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/7-v9-5cd718286059+79186-smmuv3_newapi_p2b_jgg@nvidia.comSigned-off-by: Will Deacon <will@kernel.org>

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

@@ -2005,13 +2005,14 @@ arm_smmu_atc_inv_to_cmd(int ssid, unsigned long iova, size_t size,
 	cmd->atc.size	= log2_span;
 }
 
-static int arm_smmu_atc_inv_master(struct arm_smmu_master *master)
+static int arm_smmu_atc_inv_master(struct arm_smmu_master *master,
+				   ioasid_t ssid)
 {
 	int i;
 	struct arm_smmu_cmdq_ent cmd;
 	struct arm_smmu_cmdq_batch cmds;
 
-	arm_smmu_atc_inv_to_cmd(IOMMU_NO_PASID, 0, 0, &cmd);
+	arm_smmu_atc_inv_to_cmd(ssid, 0, 0, &cmd);
 
 	cmds.num = 0;
 	for (i = 0; i < master->num_streams; i++) {
@@ -2494,7 +2495,7 @@ static void arm_smmu_enable_ats(struct arm_smmu_master *master)
 	/*
 	 * ATC invalidation of PASID 0 causes the entire ATC to be flushed.
 	 */
-	arm_smmu_atc_inv_master(master);
+	arm_smmu_atc_inv_master(master, IOMMU_NO_PASID);
 	if (pci_enable_ats(pdev, stu))
 		dev_err(master->dev, "Failed to enable ATS (STU %zu)\n", stu);
 }
@@ -2581,7 +2582,8 @@ to_smmu_domain_devices(struct iommu_domain *domain)
 }
 
 static void arm_smmu_remove_master_domain(struct arm_smmu_master *master,
-					  struct iommu_domain *domain)
+					  struct iommu_domain *domain,
+					  ioasid_t ssid)
 {
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain_devices(domain);
 	struct arm_smmu_master_domain *master_domain;
@@ -2591,8 +2593,7 @@ static void arm_smmu_remove_master_domain(struct arm_smmu_master *master,
 		return;
 
 	spin_lock_irqsave(&smmu_domain->devices_lock, flags);
-	master_domain = arm_smmu_find_master_domain(smmu_domain, master,
-						    IOMMU_NO_PASID);
+	master_domain = arm_smmu_find_master_domain(smmu_domain, master, ssid);
 	if (master_domain) {
 		list_del(&master_domain->devices_elm);
 		kfree(master_domain);
@@ -2606,6 +2607,7 @@ struct arm_smmu_attach_state {
 	/* Inputs */
 	struct iommu_domain *old_domain;
 	struct arm_smmu_master *master;
+	ioasid_t ssid;
 	/* Resulting state */
 	bool ats_enabled;
 };
@@ -2663,6 +2665,7 @@ static int arm_smmu_attach_prepare(struct arm_smmu_attach_state *state,
 		if (!master_domain)
 			return -ENOMEM;
 		master_domain->master = master;
+		master_domain->ssid = state->ssid;
 
 		/*
 		 * During prepare we want the current smmu_domain and new
@@ -2710,17 +2713,20 @@ static void arm_smmu_attach_commit(struct arm_smmu_attach_state *state)
 
 	if (state->ats_enabled && !master->ats_enabled) {
 		arm_smmu_enable_ats(master);
-	} else if (master->ats_enabled) {
+	} else if (state->ats_enabled && master->ats_enabled) {
 		/*
 		 * The translation has changed, flush the ATC. At this point the
 		 * SMMU is translating for the new domain and both the old&new
 		 * domain will issue invalidations.
 		 */
-		arm_smmu_atc_inv_master(master);
+		arm_smmu_atc_inv_master(master, state->ssid);
+	} else if (!state->ats_enabled && master->ats_enabled) {
+		/* ATS is being switched off, invalidate the entire ATC */
+		arm_smmu_atc_inv_master(master, IOMMU_NO_PASID);
 	}
 	master->ats_enabled = state->ats_enabled;
 
-	arm_smmu_remove_master_domain(master, state->old_domain);
+	arm_smmu_remove_master_domain(master, state->old_domain, state->ssid);
 }
 
 static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
@@ -2732,6 +2738,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
 	struct arm_smmu_attach_state state = {
 		.old_domain = iommu_get_domain_for_dev(dev),
+		.ssid = IOMMU_NO_PASID,
 	};
 	struct arm_smmu_master *master;
 	struct arm_smmu_cd *cdptr;
@@ -2829,6 +2836,7 @@ static int arm_smmu_attach_dev_ste(struct iommu_domain *domain,
 	struct arm_smmu_attach_state state = {
 		.master = master,
 		.old_domain = iommu_get_domain_for_dev(dev),
+		.ssid = IOMMU_NO_PASID,
 	};
 
 	if (arm_smmu_ssids_in_use(&master->cd_table))