Thread (23 messages) 23 messages, 4 authors, 2021-07-08
STALE1787d REVIEWED: 6 (6M)
Revisions (3)
  1. v13 [diff vs current]
  2. v14 current
  3. v15 [diff vs current]

[PATCH v14 2/6] iommu: Print strict or lazy mode at init time

From: John Garry <hidden>
Date: 2021-06-18 11:39:13
Also in: linux-iommu, lkml
Subsystem: iommu subsystem, the rest · Maintainers: Joerg Roedel, Will Deacon, Linus Torvalds

As well as the default domain type, it's useful to know whether strict
or lazy for DMA domains, so add this info in a separate print.

The (stict/lazy) mode may be also set via iommu.strict earlyparm, but
this will be processed prior to iommu_subsys_init(), so that print will be
accurate for drivers which don't set the mode via custom means.

For the drivers which set the mode via custom means - AMD and Intel drivers
- they maintain prints to inform a change in policy or that custom cmdline
methods to change policy are deprecated.

Signed-off-by: John Garry <redacted>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
---
 drivers/iommu/iommu.c | 5 +++++
 1 file changed, 5 insertions(+)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 5419c4b9f27a..cf58949cc2f3 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -138,6 +138,11 @@ static int __init iommu_subsys_init(void)
 		(iommu_cmd_line & IOMMU_CMD_LINE_DMA_API) ?
 			"(set via kernel command line)" : "");
 
+	pr_info("DMA domain TLB invalidation policy: %s mode %s\n",
+		iommu_dma_strict ? "strict" : "lazy",
+		(iommu_cmd_line & IOMMU_CMD_LINE_STRICT) ?
+			"(set via kernel command line)" : "");
+
 	return 0;
 }
 subsys_initcall(iommu_subsys_init);
-- 
2.26.2
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