On Tue, Mar 21, 2017 at 04:45:27PM +0100, Joerg Roedel wrote:
> On Fri, Mar 10, 2017 at 08:49:36PM +0000, Will Deacon wrote:
> > @@ -1014,8 +1027,8 @@ struct iommu_group *iommu_group_get_for_dev(struct
> > device *dev)
> > * IOMMU driver.
> > */
> > if (!group->default_domain) {
> > - group->default_domain = __iommu_domain_alloc(dev->bus,
> > - IOMMU_DOMAIN_DMA);
> > + group->default_domain =
> > + __iommu_domain_alloc(dev->bus, iommu_def_domain_type);
>
> It would be good to have a fall-back here if we are talking to an IOMMU
> driver that uses default domains, but does not support identity-mapped
> domains (yet). Exynos and Rockchip IOMMU drivers seem to fall into this
> category. A dev_warn() also makes sense in case allocating a identity
> domain fails.
Sure, something like the diff below?
Will
--->8
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 42a842e3f95f..f787626a745d 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1027,10 +1027,19 @@ struct iommu_group *iommu_group_get_for_dev(struct
device *dev)
* IOMMU driver.
*/
if (!group->default_domain) {
- group->default_domain =
- __iommu_domain_alloc(dev->bus, iommu_def_domain_type);
+ struct iommu_domain *dom;
+
+ dom = __iommu_domain_alloc(dev->bus, iommu_def_domain_type);
+ if (!dom) {
+ dev_warn(dev,
+ "failed to allocate default IOMMU domain of
type %u; falling back to IOMMU_DOMAIN_DMA",
+ iommu_def_domain_type);
+ dom = __iommu_domain_alloc(dev->bus, IOMMU_DOMAIN_DMA);
+ }
+
+ group->default_domain = dom;
if (!group->domain)
- group->domain = group->default_domain;
+ group->domain = dom;
}
ret = iommu_group_add_device(group, dev);
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