iommu: Implement DOMAIN_ATTR_PAGING attribute

This attribute of a domain can be queried to find out if the
domain supports setting up page-tables using the iommu_map()
and iommu_unmap() functions.

Signed-off-by: Joerg Roedel <joro@8bytes.org>

2 files changed, 6 insertions, 0 deletions

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 4e6d6f857e6f..0e0e5f2e0ccc 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -869,6 +869,7 @@ int iommu_domain_get_attr(struct iommu_domain *domain,
                           enum iommu_attr attr, void *data)
 {
         struct iommu_domain_geometry *geometry;
+        bool *paging;
         int ret = 0;
 
         switch (attr) {
@@ -877,6 +878,10 @@ int iommu_domain_get_attr(struct iommu_domain *domain,
                 *geometry = domain->geometry;
 
                 break;
+        case DOMAIN_ATTR_PAGING:
+                paging  = data;
+                *paging = (domain->ops->pgsize_bitmap != 0UL);
+                break;
         default:
                 if (!domain->ops->domain_get_attr)
                         return -EINVAL;
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 7e6ce7260b1c..26066f54a849 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -59,6 +59,7 @@ struct iommu_domain {
 
 enum iommu_attr {
         DOMAIN_ATTR_GEOMETRY,
+        DOMAIN_ATTR_PAGING,
         DOMAIN_ATTR_MAX,
 };