Re: [PATCH v2 4/4] iommu: Get DT/ACPI parsing into the proper probe path

[Robin Murphy <robin.murphy@arm.com>]

On 2025-03-11 6:42 pm, Joerg Roedel wrote:
> Hi Robin,
> 
> On Fri, Feb 28, 2025 at 03:46:33PM +0000, Robin Murphy wrote:
>> +	/*
>> +	 * And if we do now see any replay calls, they would indicate someone
>> +	 * misusing the dma_configure path outside bus code.
>> +	 */
>> +	if (dev->driver)
>> +		dev_WARN(dev, "late IOMMU probe at driver bind, something fishy here!\n");
> 
> This warning triggers on my workstation (with an AMD IOMMU), any ideas?

Argh! When I moved the dma_configure call into iommu_init_device() for
v2 I moved the warning with it, but of course that needs to stay where
it was, *after* the point that ops->probe_device has had a chance to
filter out irrelevant devices. Does this make it behave?

Thanks,
Robin.

----->8-----
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 09798ddbce9d..1da6c55a0d02 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -437,12 +437,6 @@ static int iommu_init_device(struct device *dev)
  		ret = -ENODEV;
  		goto err_free;
  	}
-	/*
-	 * And if we do now see any replay calls, they would indicate someone
-	 * misusing the dma_configure path outside bus code.
-	 */
-	if (dev->driver)
-		dev_WARN(dev, "late IOMMU probe at driver bind, something fishy here!\n");
  
  	if (!try_module_get(ops->owner)) {
  		ret = -EINVAL;
@@ -565,6 +559,12 @@ static int __iommu_probe_device(struct device *dev, struct list_head *group_list
  	ret = iommu_init_device(dev);
  	if (ret)
  		return ret;
+	/*
+	 * And if we do now see any replay calls, they would indicate someone
+	 * misusing the dma_configure path outside bus code.
+	 */
+	if (dev->driver)
+		dev_WARN(dev, "late IOMMU probe at driver bind, something fishy here!\n");
  
  	group = dev->iommu_group;
  	gdev = iommu_group_alloc_device(group, dev);