iommu: Introduce explicit type for non-strict DMA domains

Promote the difference between strict and non-strict DMA domains from an
internal detail to a distinct domain feature and type, to pave the road
for exposing it through the sysfs default domain interface.

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/08cd2afaf6b63c58ad49acec3517c9b32c2bb946.1628682049.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 1eacbbd..17ac3dd 100644 (file)
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1319,7 +1319,7 @@ void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 dma_limit)
         * The IOMMU core code allocates the default DMA domain, which the
         * underlying IOMMU driver needs to support via the dma-iommu layer.
         */
-       if (domain->type == IOMMU_DOMAIN_DMA) {
+       if (iommu_is_dma_domain(domain)) {
                if (iommu_dma_init_domain(domain, dma_base, dma_limit, dev))
                        goto out_err;
                dev->dma_ops = &iommu_dma_ops;

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index b65fcc6..17d6728 100644 (file)
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -115,6 +115,7 @@ static const char *iommu_domain_type_str(unsigned int t)
        case IOMMU_DOMAIN_UNMANAGED:
                return "Unmanaged";
        case IOMMU_DOMAIN_DMA:
+       case IOMMU_DOMAIN_DMA_FQ:
                return "Translated";
        default:
                return "Unknown";
@@ -552,6 +553,9 @@ static ssize_t iommu_group_show_type(struct iommu_group *group,
                case IOMMU_DOMAIN_DMA:
                        type = "DMA\n";
                        break;
+               case IOMMU_DOMAIN_DMA_FQ:
+                       type = "DMA-FQ\n";
+                       break;
                }
        }
        mutex_unlock(&group->mutex);
@@ -765,7 +769,7 @@ static int iommu_create_device_direct_mappings(struct iommu_group *group,
        unsigned long pg_size;
        int ret = 0;
 
-       if (!domain || domain->type != IOMMU_DOMAIN_DMA)
+       if (!domain || !iommu_is_dma_domain(domain))
                return 0;
 
        BUG_ON(!domain->pgsize_bitmap);
@@ -1948,7 +1952,7 @@ static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
        domain->pgsize_bitmap  = bus->iommu_ops->pgsize_bitmap;
 
        /* Temporarily avoid -EEXIST while drivers still get their own cookies */
-       if (type == IOMMU_DOMAIN_DMA && !domain->iova_cookie && iommu_get_dma_cookie(domain)) {
+       if (iommu_is_dma_domain(domain) && !domain->iova_cookie && iommu_get_dma_cookie(domain)) {
                iommu_domain_free(domain);
                domain = NULL;
        }

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index f7679f6..5629ae4 100644 (file)
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -61,6 +61,7 @@ struct iommu_domain_geometry {
 #define __IOMMU_DOMAIN_DMA_API (1U << 1)  /* Domain for use in DMA-API
                                              implementation              */
 #define __IOMMU_DOMAIN_PT      (1U << 2)  /* Domain is identity mapped   */
+#define __IOMMU_DOMAIN_DMA_FQ  (1U << 3)  /* DMA-API uses flush queue    */
 
 /*
  * This are the possible domain-types
@@ -73,12 +74,17 @@ struct iommu_domain_geometry {
  *     IOMMU_DOMAIN_DMA        - Internally used for DMA-API implementations.
  *                               This flag allows IOMMU drivers to implement
  *                               certain optimizations for these domains
+ *     IOMMU_DOMAIN_DMA_FQ     - As above, but definitely using batched TLB
+ *                               invalidation.
  */
 #define IOMMU_DOMAIN_BLOCKED   (0U)
 #define IOMMU_DOMAIN_IDENTITY  (__IOMMU_DOMAIN_PT)
 #define IOMMU_DOMAIN_UNMANAGED (__IOMMU_DOMAIN_PAGING)
 #define IOMMU_DOMAIN_DMA       (__IOMMU_DOMAIN_PAGING |        \
                                 __IOMMU_DOMAIN_DMA_API)
+#define IOMMU_DOMAIN_DMA_FQ    (__IOMMU_DOMAIN_PAGING |        \
+                                __IOMMU_DOMAIN_DMA_API |       \
+                                __IOMMU_DOMAIN_DMA_FQ)
 
 struct iommu_domain {
        unsigned type;
@@ -90,6 +96,11 @@ struct iommu_domain {
        struct iommu_dma_cookie *iova_cookie;
 };
 
+static inline bool iommu_is_dma_domain(struct iommu_domain *domain)
+{
+       return domain->type & __IOMMU_DOMAIN_DMA_API;
+}
+
 enum iommu_cap {
        IOMMU_CAP_CACHE_COHERENCY,      /* IOMMU can enforce cache coherent DMA
                                           transactions */