iommu: Use flush queue capability

It remains really handy to have distinct DMA domain types within core
code for the sake of default domain policy selection, but we can now
hide that detail from drivers by using the new capability instead.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Jerry Snitselaar <jsnitsel@redhat.com> # amd, intel, smmu-v3
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/1c552d99e8ba452bdac48209fa74c0bdd52fd9d9.1683233867.git.robin.murphy@arm.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

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

@@ -2024,7 +2024,6 @@ static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
 
 	if (type != IOMMU_DOMAIN_UNMANAGED &&
 	    type != IOMMU_DOMAIN_DMA &&
-	    type != IOMMU_DOMAIN_DMA_FQ &&
 	    type != IOMMU_DOMAIN_IDENTITY)
 		return NULL;
 

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

@@ -856,8 +856,7 @@ static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
 	struct arm_smmu_domain *smmu_domain;
 
 	if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_IDENTITY) {
-		if (using_legacy_binding ||
-		    (type != IOMMU_DOMAIN_DMA && type != IOMMU_DOMAIN_DMA_FQ))
+		if (using_legacy_binding || type != IOMMU_DOMAIN_DMA)
 			return NULL;
 	}
 	/*

drivers/iommu/dma-iommu.c

@@ -586,7 +586,8 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
 		goto done_unlock;
 
 	/* If the FQ fails we can simply fall back to strict mode */
-	if (domain->type == IOMMU_DOMAIN_DMA_FQ && iommu_dma_init_fq(domain))
+	if (domain->type == IOMMU_DOMAIN_DMA_FQ &&
+	    (!device_iommu_capable(dev, IOMMU_CAP_DEFERRED_FLUSH) || iommu_dma_init_fq(domain)))
 		domain->type = IOMMU_DOMAIN_DMA;
 
 	ret = iova_reserve_iommu_regions(dev, domain);

drivers/iommu/intel/iommu.c

@@ -4064,7 +4064,6 @@ static struct iommu_domain *intel_iommu_domain_alloc(unsigned type)
 	case IOMMU_DOMAIN_BLOCKED:
 		return &blocking_domain;
 	case IOMMU_DOMAIN_DMA:
-	case IOMMU_DOMAIN_DMA_FQ:
 	case IOMMU_DOMAIN_UNMANAGED:
 		dmar_domain = alloc_domain(type);
 		if (!dmar_domain) {

drivers/iommu/iommu.c

@@ -1980,11 +1980,12 @@ static struct iommu_domain *__iommu_domain_alloc(const struct bus_type *bus,
 						 unsigned type)
 {
 	struct iommu_domain *domain;
+	unsigned int alloc_type = type & IOMMU_DOMAIN_ALLOC_FLAGS;
 
 	if (bus == NULL || bus->iommu_ops == NULL)
 		return NULL;
 
-	domain = bus->iommu_ops->domain_alloc(type);
+	domain = bus->iommu_ops->domain_alloc(alloc_type);
 	if (!domain)
 		return NULL;
 

include/linux/iommu.h

@@ -65,6 +65,7 @@ struct iommu_domain_geometry {
 
 #define __IOMMU_DOMAIN_SVA	(1U << 4)  /* Shared process address space */
 
+#define IOMMU_DOMAIN_ALLOC_FLAGS ~__IOMMU_DOMAIN_DMA_FQ
 /*
  * This are the possible domain-types
  *