On Tue, Jan 27, 2015 at 12:08:56AM +0000, Joerg Roedel wrote:
From: Joerg Roedel <jroedel@xxxxxxx>
The default domain will be used (if supported by the iommu
driver) when the devices in the iommu group are not attached
to any other domain.
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
---
drivers/iommu/iommu.c | 26 +++++++++++++++++++++++---
1 file changed, 23 insertions(+), 3 deletions(-)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 34636eb..8f33ddd3 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -76,6 +76,9 @@ struct iommu_group_attribute iommu_group_attr_##_name = \
#define to_iommu_group(_kobj) \
container_of(_kobj, struct iommu_group, kobj)
+static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
+ enum iommu_domain_type type);
+
static ssize_t iommu_group_attr_show(struct kobject *kobj,
struct attribute *__attr, char *buf)
{
@@ -362,6 +365,17 @@ rename:
kobject_get(group->devices_kobj);
+ /*
+ * Try to allocate a default domain for the group, if this
+ * hasn't happened yet. This is not the best place to do that,
+ * it should happen in iommu_group_alloc(). But we have no
+ * iommu_ops there yet, so the allocation has to happen here for
+ * now.
+ */
+ if (group->default_domain == NULL)
+ group->default_domain = __iommu_domain_alloc(dev->bus,
+ IOMMU_DOMAIN_DMA);
Having a per-group domain is wasteful for IOMMUs that only support a modest
number of concurrent domains, so in reality I think we need to have one
domain per IOMMU instance. Is that possible?
One problem with the current per-bus approach is that __iommu_domain_alloc
can't figure out which IOMMU instance corresponds to the group.