linux-kernel - [PATCH] iommu/vt-d: Do not falsely log intel

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Date:   Tue, 31 Aug 2021 12:29:47 +0100
From:   Tvrtko Ursulin <tvrtko.ursulin@...ux.intel.com>
To:     iommu@...ts.linux-foundation.org
Cc:     linux-kernel@...r.kernel.org,
        Tvrtko Ursulin <tvrtko.ursulin@...el.com>,
        Eero Tamminen <eero.t.tamminen@...el.com>,
        Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH] iommu/vt-d: Do not falsely log intel_iommu is unsupported kernel option

From: Tvrtko Ursulin <tvrtko.ursulin@...el.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.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@...el.com>
Reported-by: Eero Tamminen <eero.t.tamminen@...el.com>
Cc: Lu Baolu <baolu.lu@...ux.intel.com>
---
 drivers/iommu/intel/iommu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 327f477a8553..41d163e275b2 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -463,13 +463,15 @@ 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);
 
-- 
2.30.2