iommu: Generalize PASID 0 for normal DMA w/o PASID

PCIe Process address space ID (PASID) is used to tag DMA traffic, it
provides finer grained isolation than requester ID (RID).

For each device/RID, 0 is a special PASID for the normal DMA (no
PASID). This is universal across all architectures that supports PASID,
therefore warranted to be reserved globally and declared in the common
header. Consequently, we can avoid the conflict between different PASID
use cases in the generic code. e.g. SVA and DMA API with PASIDs.

This paved away for device drivers to choose global PASID policy while
continue doing normal DMA.

Noting that VT-d could support none-zero RID/NO_PASID, but currently not
used.
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Link: https://lore.kernel.org/r/20230802212427.1497170-2-jacob.jun.pan@linux.intel.comSigned-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

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

@@ -80,7 +80,7 @@ arm_smmu_share_asid(struct mm_struct *mm, u16 asid)
 	 * be some overlap between use of both ASIDs, until we invalidate the
 	 * TLB.
 	 */
-	arm_smmu_write_ctx_desc(smmu_domain, 0, cd);
+	arm_smmu_write_ctx_desc(smmu_domain, IOMMU_NO_PASID, cd);
 
 	/* Invalidate TLB entries previously associated with that context */
 	arm_smmu_tlb_inv_asid(smmu, asid);

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

@@ -1059,7 +1059,7 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 	/*
 	 * This function handles the following cases:
 	 *
-	 * (1) Install primary CD, for normal DMA traffic (SSID = 0).
+	 * (1) Install primary CD, for normal DMA traffic (SSID = IOMMU_NO_PASID = 0).
 	 * (2) Install a secondary CD, for SID+SSID traffic.
 	 * (3) Update ASID of a CD. Atomically write the first 64 bits of the
 	 *     CD, then invalidate the old entry and mappings.
@@ -1607,7 +1607,7 @@ static void arm_smmu_handle_ppr(struct arm_smmu_device *smmu, u64 *evt)
 
 	sid = FIELD_GET(PRIQ_0_SID, evt[0]);
 	ssv = FIELD_GET(PRIQ_0_SSID_V, evt[0]);
-	ssid = ssv ? FIELD_GET(PRIQ_0_SSID, evt[0]) : 0;
+	ssid = ssv ? FIELD_GET(PRIQ_0_SSID, evt[0]) : IOMMU_NO_PASID;
 	last = FIELD_GET(PRIQ_0_PRG_LAST, evt[0]);
 	grpid = FIELD_GET(PRIQ_1_PRG_IDX, evt[1]);
 
@@ -1748,7 +1748,7 @@ arm_smmu_atc_inv_to_cmd(int ssid, unsigned long iova, size_t size,
 	 */
 	*cmd = (struct arm_smmu_cmdq_ent) {
 		.opcode			= CMDQ_OP_ATC_INV,
-		.substream_valid	= !!ssid,
+		.substream_valid	= (ssid != IOMMU_NO_PASID),
 		.atc.ssid		= ssid,
 	};
 
@@ -1795,7 +1795,7 @@ static int arm_smmu_atc_inv_master(struct arm_smmu_master *master)
 	struct arm_smmu_cmdq_ent cmd;
 	struct arm_smmu_cmdq_batch cmds;
 
-	arm_smmu_atc_inv_to_cmd(0, 0, 0, &cmd);
+	arm_smmu_atc_inv_to_cmd(IOMMU_NO_PASID, 0, 0, &cmd);
 
 	cmds.num = 0;
 	for (i = 0; i < master->num_streams; i++) {
@@ -1875,7 +1875,7 @@ static void arm_smmu_tlb_inv_context(void *cookie)
 		cmd.tlbi.vmid	= smmu_domain->s2_cfg.vmid;
 		arm_smmu_cmdq_issue_cmd_with_sync(smmu, &cmd);
 	}
-	arm_smmu_atc_inv_domain(smmu_domain, 0, 0, 0);
+	arm_smmu_atc_inv_domain(smmu_domain, IOMMU_NO_PASID, 0, 0);
 }
 
 static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd,
@@ -1968,7 +1968,7 @@ static void arm_smmu_tlb_inv_range_domain(unsigned long iova, size_t size,
 	 * Unfortunately, this can't be leaf-only since we may have
 	 * zapped an entire table.
 	 */
-	arm_smmu_atc_inv_domain(smmu_domain, 0, iova, size);
+	arm_smmu_atc_inv_domain(smmu_domain, IOMMU_NO_PASID, iova, size);
 }
 
 void arm_smmu_tlb_inv_range_asid(unsigned long iova, size_t size, int asid,
@@ -2142,7 +2142,7 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 	 * 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, 0, &cfg->cd);
+	ret = arm_smmu_write_ctx_desc(smmu_domain, IOMMU_NO_PASID, &cfg->cd);
 	if (ret)
 		goto out_free_cd_tables;
 
@@ -2328,7 +2328,7 @@ static void arm_smmu_enable_ats(struct arm_smmu_master *master)
 	pdev = to_pci_dev(master->dev);
 
 	atomic_inc(&smmu_domain->nr_ats_masters);
-	arm_smmu_atc_inv_domain(smmu_domain, 0, 0, 0);
+	arm_smmu_atc_inv_domain(smmu_domain, IOMMU_NO_PASID, 0, 0);
 	if (pci_enable_ats(pdev, stu))
 		dev_err(master->dev, "Failed to enable ATS (STU %zu)\n", stu);
 }

drivers/iommu/intel/iommu.c

@@ -877,7 +877,7 @@ void dmar_fault_dump_ptes(struct intel_iommu *iommu, u16 source_id,
 	}
 	/* For request-without-pasid, get the pasid from context entry */
 	if (intel_iommu_sm && pasid == IOMMU_PASID_INVALID)
-		pasid = PASID_RID2PASID;
+		pasid = IOMMU_NO_PASID;
 
 	dir_index = pasid >> PASID_PDE_SHIFT;
 	pde = &dir[dir_index];
@@ -1449,7 +1449,7 @@ static void __iommu_flush_dev_iotlb(struct device_domain_info *info,
 	qdep = info->ats_qdep;
 	qi_flush_dev_iotlb(info->iommu, sid, info->pfsid,
 			   qdep, addr, mask);
-	quirk_extra_dev_tlb_flush(info, addr, mask, PASID_RID2PASID, qdep);
+	quirk_extra_dev_tlb_flush(info, addr, mask, IOMMU_NO_PASID, qdep);
 }
 
 static void iommu_flush_dev_iotlb(struct dmar_domain *domain,
@@ -1484,7 +1484,7 @@ static void iommu_flush_iotlb_psi(struct intel_iommu *iommu,
 		ih = 1 << 6;
 
 	if (domain->use_first_level) {
-		qi_flush_piotlb(iommu, did, PASID_RID2PASID, addr, pages, ih);
+		qi_flush_piotlb(iommu, did, IOMMU_NO_PASID, addr, pages, ih);
 	} else {
 		unsigned long bitmask = aligned_pages - 1;
 
@@ -1554,7 +1554,7 @@ static void intel_flush_iotlb_all(struct iommu_domain *domain)
 		u16 did = domain_id_iommu(dmar_domain, iommu);
 
 		if (dmar_domain->use_first_level)
-			qi_flush_piotlb(iommu, did, PASID_RID2PASID, 0, -1, 0);
+			qi_flush_piotlb(iommu, did, IOMMU_NO_PASID, 0, -1, 0);
 		else
 			iommu->flush.flush_iotlb(iommu, did, 0, 0,
 						 DMA_TLB_DSI_FLUSH);
@@ -1940,7 +1940,7 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
 				context_pdts(pds);
 
 		/* Setup the RID_PASID field: */
-		context_set_sm_rid2pasid(context, PASID_RID2PASID);
+		context_set_sm_rid2pasid(context, IOMMU_NO_PASID);
 
 		/*
 		 * Setup the Device-TLB enable bit and Page request
@@ -2420,13 +2420,13 @@ static int dmar_domain_attach_device(struct dmar_domain *domain,
 		/* Setup the PASID entry for requests without PASID: */
 		if (hw_pass_through && domain_type_is_si(domain))
 			ret = intel_pasid_setup_pass_through(iommu, domain,
-					dev, PASID_RID2PASID);
+					dev, IOMMU_NO_PASID);
 		else if (domain->use_first_level)
 			ret = domain_setup_first_level(iommu, domain, dev,
-					PASID_RID2PASID);
+					IOMMU_NO_PASID);
 		else
 			ret = intel_pasid_setup_second_level(iommu, domain,
-					dev, PASID_RID2PASID);
+					dev, IOMMU_NO_PASID);
 		if (ret) {
 			dev_err(dev, "Setup RID2PASID failed\n");
 			device_block_translation(dev);
@@ -3968,7 +3968,7 @@ static void dmar_remove_one_dev_info(struct device *dev)
 	if (!dev_is_real_dma_subdevice(info->dev)) {
 		if (dev_is_pci(info->dev) && sm_supported(iommu))
 			intel_pasid_tear_down_entry(iommu, info->dev,
-					PASID_RID2PASID, false);
+					IOMMU_NO_PASID, false);
 
 		iommu_disable_pci_caps(info);
 		domain_context_clear(info);
@@ -3997,7 +3997,7 @@ static void device_block_translation(struct device *dev)
 	if (!dev_is_real_dma_subdevice(dev)) {
 		if (sm_supported(iommu))
 			intel_pasid_tear_down_entry(iommu, dev,
-						    PASID_RID2PASID, false);
+						    IOMMU_NO_PASID, false);
 		else
 			domain_context_clear(info);
 	}
@@ -4331,7 +4331,7 @@ static void domain_set_force_snooping(struct dmar_domain *domain)
 
 	list_for_each_entry(info, &domain->devices, link)
 		intel_pasid_setup_page_snoop_control(info->iommu, info->dev,
-						     PASID_RID2PASID);
+						     IOMMU_NO_PASID);
 }
 
 static bool intel_iommu_enforce_cache_coherency(struct iommu_domain *domain)
@@ -4987,7 +4987,7 @@ void quirk_extra_dev_tlb_flush(struct device_domain_info *info,
 		return;
 
 	sid = PCI_DEVID(info->bus, info->devfn);
-	if (pasid == PASID_RID2PASID) {
+	if (pasid == IOMMU_NO_PASID) {
 		qi_flush_dev_iotlb(info->iommu, sid, info->pfsid,
 				   qdep, address, mask);
 	} else {

drivers/iommu/intel/pasid.c

@@ -438,7 +438,7 @@ devtlb_invalidation_with_pasid(struct intel_iommu *iommu,
 	 * SVA usage, device could do DMA with multiple PASIDs. It is more
 	 * efficient to flush devTLB specific to the PASID.
 	 */
-	if (pasid == PASID_RID2PASID)
+	if (pasid == IOMMU_NO_PASID)
 		qi_flush_dev_iotlb(iommu, sid, pfsid, qdep, 0, 64 - VTD_PAGE_SHIFT);
 	else
 		qi_flush_dev_iotlb_pasid(iommu, sid, pfsid, pasid, qdep, 0, 64 - VTD_PAGE_SHIFT);

drivers/iommu/intel/pasid.h

@@ -10,8 +10,6 @@
 #ifndef __INTEL_PASID_H
 #define __INTEL_PASID_H
 
-#define PASID_RID2PASID			0x0
-#define PASID_MIN			0x1
 #define PASID_MAX			0x100000
 #define PASID_PTE_MASK			0x3F
 #define PASID_PTE_PRESENT		1

include/linux/iommu.h

@@ -196,6 +196,7 @@ enum iommu_dev_features {
 	IOMMU_DEV_FEAT_IOPF,
 };
 
+#define IOMMU_NO_PASID	(0U) /* Reserved for DMA w/o PASID */
 #define IOMMU_PASID_INVALID	(-1U)
 typedef unsigned int ioasid_t;