[PATCH 1/9] iommu/vt-d: Do not falsely log intel_iommu is unsupported kernel option

Lu Baolu
2021-10-14T05:42:51Z

From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

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>
---
drivers/iommu/intel/iommu.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index d75f59ae28e6..9a356075d345 100644
--- 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);