iommu/amd: Put IOMMUv2 devices in a direct mapped domain

Hello Joerg Roedel,

This is a semi-automatic email about new static checker warnings.

The patch 0a3da4517107: "iommu/amd: Put IOMMUv2 devices in a direct mapped domain" from May 28, 2015, leads to the following Smatch complaint:

drivers/iommu/amd_iommu.c:2285 amd_iommu_add_device()
error: we previously assumed 'dev_data' could be null (see line 2279)

drivers/iommu/amd_iommu.c
2278 dev_data = get_dev_data(dev);
2279 if (dev_data && dev_data->iommu_v2)

                    ^^^^^^^^

Check.

2280 iommu_request_dm_for_dev(dev);
2281
2282 /* Domains are initialized for this device - have a look what we ended up with */
2283 domain = iommu_get_domain_for_dev(dev);
2284 if (domain->type == IOMMU_DOMAIN_IDENTITY) {

  2285			dev_data->passthrough = true;
                        ^^^^^^^^^^

Unchecked dereference.

  2286			dev->archdata.dma_ops = &nommu_dma_ops;
  2287		} else {

regards,
dan carpenter

Hi Dan,

This was a bit more complicated. I fixed it with this add-on patch:

From: Joerg Roedel <[email protected]>
Date: Thu, 11 Jun 2015 09:21:39 +0200
Subject: [PATCH] iommu/amd: Handle errors returned from iommu_init_device

Without this patch only -ENOTSUPP is handled, but there are other possible errors. Handle them too.

---
 drivers/iommu/amd_iommu.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

index 6659b51..73fc4b7 100644
@@ -2265,7 +2265,11 @@ static int amd_iommu_add_device(struct device *dev)
 	iommu = amd_iommu_rlookup_table[devid];
 
 	ret = iommu_init_device(dev);
-	if (ret == -ENOTSUPP) {
+	if (ret) {
+		if (ret != -ENOTSUPP)
+			pr_err("Failed to initialize device %s - trying to proceed anyway\n",
+				dev_name(dev));
+
 		iommu_ignore_device(dev);
 		dev->archdata.dma_ops = &nommu_dma_ops;
 		goto out;

@@ -2273,7 +2277,10 @@ static int amd_iommu_add_device(struct device *dev)
 	init_iommu_group(dev);
 
 	dev_data = get_dev_data(dev);
-	if (dev_data && dev_data->iommu_v2)
+
+	BUG_ON(!dev_data);
+
+	if (dev_data->iommu_v2)
 		iommu_request_dm_for_dev(dev);
 
 	/* Domains are initialized for this device - have a look what we ended up with */

1.8.4.5