[PATCH 4/5] iommu: Make sure a device is always attached to a domain

Joerg Roedel
2015-01-27T00:10:23Z

From: Joerg Roedel <jroedel@suse.de>

Make use of the default domain and re-attach a device to it
when it is detached from another domain. Also enforce that a
device has to be in the default domain before it can be
attached to a different domain.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
drivers/iommu/iommu.c | 34 +++++++++++++++++++++++++++++++---
1 file changed, 31 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index b63a550..5080759 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -53,6 +53,7 @@ struct iommu_group {
int id;
unsigned dev_cnt;
struct iommu_domain *default_domain;
+ struct iommu_domain *domain;
};

struct iommu_device {
@@ -1040,8 +1041,17 @@ static int iommu_group_do_attach_device(struct device *dev, void *data)

int iommu_attach_group(struct iommu_domain *domain, struct iommu_group *group)
{
- return iommu_group_for_each_dev(group, domain,
- iommu_group_do_attach_device);
+ int ret;
+
+ if (group->default_domain && group->domain != group->default_domain)
+ return -EBUSY;
+
+ ret = iommu_group_for_each_dev(group, domain,
+ iommu_group_do_attach_device);
+ if (ret == 0)
+ group->domain = domain;
+
+ return ret;
}
EXPORT_SYMBOL_GPL(iommu_attach_group);

@@ -1056,7 +1066,25 @@ static int iommu_group_do_detach_device(struct device *dev, void *data)

void iommu_detach_group(struct iommu_domain *domain, struct iommu_group *group)
{
- iommu_group_for_each_dev(group, domain, iommu_group_do_detach_device);
+ int ret;
+
+ if (!group->default_domain) {
+ iommu_group_for_each_dev(group, domain,
+ iommu_group_do_detach_device);
+ group->domain = NULL;
+ return;
+ }
+
+ if (group->domain == group->default_domain)
+ return;
+
+ /* Detach by re-attaching to the default domain */
+ ret = iommu_group_for_each_dev(group, group->default_domain,
+ iommu_group_do_attach_device);
+ if (ret != 0)
+ WARN_ON(1);
+ else
+ group->domain = group->default_domain;
}
EXPORT_SYMBOL_GPL(iommu_detach_group);

--
1.9.1