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.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

3 files changed, 13 insertions, 15 deletions

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 5c8c5cdc36cf..ddff43def3ab 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/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 {
diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index c5d479770e12..23dca3bc319d 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/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);
diff --git a/drivers/iommu/intel/pasid.h b/drivers/iommu/intel/pasid.h
index d6b7d21244b1..4e9e68c3c388 100644
--- a/drivers/iommu/intel/pasid.h
+++ b/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