On 6/17/21 3:41 PM, John Garry wrote:
@@ -349,10 +349,9 @@ static int __init iommu_dma_setup(char *str)
}
early_param("iommu.strict", iommu_dma_setup);
-void iommu_set_dma_strict(bool strict)
+void iommu_set_dma_strict(void)
{
- if (strict || !(iommu_cmd_line & IOMMU_CMD_LINE_STRICT))
- iommu_dma_strict = strict;
+ iommu_dma_strict = true;
Sorry, I still can't get how iommu.strict kernel option works.
static int __init iommu_dma_setup(char *str)
{
int ret = kstrtobool(str, &iommu_dma_strict);
if (!ret)
iommu_cmd_line |= IOMMU_CMD_LINE_STRICT;
return ret;
}
early_param("iommu.strict", iommu_dma_setup);
The bit IOMMU_CMD_LINE_STRICT is only set, but not used anywhere.
It is used in patch 2/6:
+ 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)" : "");
Hence,
I am wondering how could it work? A bug or I missed anything?
It is really just used for informative purpose now.
I am clear now. Thanks!
Best regards,
baolu
