iommu/vt-d: Do not falsely log intel_iommu is unsupported kernel option

Handling of intel_iommu kernel command line option should return "true" to
indicate option is valid and so avoid logging it as unknown by the core
parsing code.

Also log unknown sub-options at the notice level to let user know of
potential typos or similar.

Reported-by: Eero Tamminen <eero.t.tamminen@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://lore.kernel.org/r/20210831112947.310080-1-tvrtko.ursulin@linux.intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20211014053839.727419-2-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index d75f59a..9a35607 100644 (file)
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -412,6 +412,7 @@ static int __init intel_iommu_setup(char *str)
 {
        if (!str)
                return -EINVAL;
+
        while (*str) {
                if (!strncmp(str, "on", 2)) {
                        dmar_disabled = 0;
@@ -441,13 +442,16 @@ static int __init intel_iommu_setup(char *str)
                } else if (!strncmp(str, "tboot_noforce", 13)) {
                        pr_info("Intel-IOMMU: not forcing on after tboot. This could expose security risk for tboot\n");
                        intel_iommu_tboot_noforce = 1;
+               } else {
+                       pr_notice("Unknown option - '%s'\n", str);
                }
 
                str += strcspn(str, ",");
                while (*str == ',')
                        str++;
        }
-       return 0;
+
+       return 1;
 }
 __setup("intel_iommu=", intel_iommu_setup);