iommu: Introduce iommu domain types

This allows to handle domains differently based on their
type in the future. An IOMMU driver can implement certain
optimizations for DMA-API domains for example.

The domain types can be extended later and some of the
existing domain attributes can be migrated to become domain
flags.

Tested-by: Thierry Reding <treding@nvidia.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 11de262..4920605 100644 (file)
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -909,14 +909,15 @@ struct iommu_domain *iommu_domain_alloc(struct bus_type *bus)
        ops = bus->iommu_ops;
 
        if (ops->domain_alloc)
-               domain = ops->domain_alloc();
+               domain = ops->domain_alloc(IOMMU_DOMAIN_UNMANAGED);
        else
                domain = kzalloc(sizeof(*domain), GFP_KERNEL);
 
        if (!domain)
                return NULL;
 
-       domain->ops = bus->iommu_ops;
+       domain->ops  = bus->iommu_ops;
+       domain->type = IOMMU_DOMAIN_UNMANAGED;
 
        if (ops->domain_init && domain->ops->domain_init(domain))
                goto out_free;

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 69d1d12..72d03fe 100644 (file)
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -51,7 +51,32 @@ struct iommu_domain_geometry {
        bool force_aperture;       /* DMA only allowed in mappable range? */
 };
 
+/* Domain feature flags */
+#define __IOMMU_DOMAIN_PAGING  (1U << 0)  /* Support for iommu_map/unmap */
+#define __IOMMU_DOMAIN_DMA_API (1U << 1)  /* Domain for use in DMA-API
+                                             implementation              */
+#define __IOMMU_DOMAIN_PT      (1U << 2)  /* Domain is identity mapped   */
+
+/*
+ * This are the possible domain-types
+ *
+ *     IOMMU_DOMAIN_BLOCKED    - All DMA is blocked, can be used to isolate
+ *                               devices
+ *     IOMMU_DOMAIN_IDENTITY   - DMA addresses are system physical addresses
+ *     IOMMU_DOMAIN_UNMANAGED  - DMA mappings managed by IOMMU-API user, used
+ *                               for VMs
+ *     IOMMU_DOMAIN_DMA        - Internally used for DMA-API implementations.
+ *                               This flag allows IOMMU drivers to implement
+ *                               certain optimizations for these domains
+ */
+#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)
+
 struct iommu_domain {
+       unsigned type;
        const struct iommu_ops *ops;
        void *priv;
        iommu_fault_handler_t handler;
@@ -117,7 +142,7 @@ struct iommu_ops {
        void (*domain_destroy)(struct iommu_domain *domain);
 
        /* Domain allocation and freeing by the iommu driver */
-       struct iommu_domain *(*domain_alloc)(void);
+       struct iommu_domain *(*domain_alloc)(unsigned iommu_domain_type);
        void (*domain_free)(struct iommu_domain *);
 
        int (*attach_dev)(struct iommu_domain *domain, struct device *dev);