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>

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 8add9f125d3efed3d066109fba44b472f450301e..036fe9bf157e0341862c8452ed47ca02b32db3c3 100644 (file)
--- 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);