iommu/amd: Don't initialize IOMMUv2 resources when not required

Add a check to the init-path of the AMD IOMMUv2 driver if
the hardware is available in the system. Only allocate all
the resources if it is really available.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

1 files changed, 13 insertions, 1 deletions

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 8add9f125d3e..036fe9bf157e 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -921,7 +921,16 @@ static int __init amd_iommu_v2_init(void)
         size_t state_table_size;
         int ret;
 
-        pr_info("AMD IOMMUv2 driver by Joerg Roedel <joerg.roedel@amd.com>");
+        pr_info("AMD IOMMUv2 driver by Joerg Roedel <joerg.roedel@amd.com>\n");
+
+        if (!amd_iommu_v2_supported()) {
+                pr_info("AMD IOMMUv2 functionality not available on this sytem\n");
+                /*
+                 * Load anyway to provide the symbols to other modules
+                 * which may use AMD IOMMUv2 optionally.
+                 */
+                return 0;
+        }
 
         spin_lock_init(&state_lock);
 
@@ -961,6 +970,9 @@ static void __exit amd_iommu_v2_exit(void)
         size_t state_table_size;
         int i;
 
+        if (!amd_iommu_v2_supported())
+                return;
+
         profile_event_unregister(PROFILE_TASK_EXIT, &profile_nb);
         amd_iommu_unregister_ppr_notifier(&ppr_nb);