[PATCH 2/2] vfio/type1: Update group->domain after aux attach and detach

[Lu Baolu]

Update group->domain whenever an aux-domain is attached to or detached
from a mediated device. Without this change, iommu_get_domain_for_dev()
will be broken for mdev devices.

Fixes: 7bd50f0cd2fd5 ("vfio/type1: Add domain at(de)taching group helpers")
Signed-off-by: Lu Baolu <baolu...@linux.intel.com>
---
 drivers/vfio/vfio_iommu_type1.c | 37 ++++++++++++++++++++++++++++-----
 1 file changed, 32 insertions(+), 5 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 5e556ac9102a..e0d8802ce0c9 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -1634,10 +1634,28 @@ static int vfio_mdev_attach_domain(struct device *dev, 
void *data)
 
        iommu_device = vfio_mdev_get_iommu_device(dev);
        if (iommu_device) {
-               if (iommu_dev_feature_enabled(iommu_device, IOMMU_DEV_FEAT_AUX))
-                       return iommu_aux_attach_device(domain, iommu_device);
-               else
+               if (iommu_dev_feature_enabled(iommu_device,
+                                             IOMMU_DEV_FEAT_AUX)) {
+                       struct iommu_group *group = iommu_group_get(dev);
+                       int ret;
+
+                       if (!group)
+                               return -EINVAL;
+
+                       if (iommu_group_get_domain(group)) {
+                               iommu_group_put(group);
+                               return -EBUSY;
+                       }
+
+                       ret = iommu_aux_attach_device(domain, iommu_device);
+                       if (!ret)
+                               iommu_group_set_domain(group, domain);
+
+                       iommu_group_put(group);
+                       return ret;
+               } else {
                        return iommu_attach_device(domain, iommu_device);
+               }
        }
 
        return -EINVAL;
@@ -1650,10 +1668,19 @@ static int vfio_mdev_detach_domain(struct device *dev, 
void *data)
 
        iommu_device = vfio_mdev_get_iommu_device(dev);
        if (iommu_device) {
-               if (iommu_dev_feature_enabled(iommu_device, IOMMU_DEV_FEAT_AUX))
+               if (iommu_dev_feature_enabled(iommu_device,
+                                             IOMMU_DEV_FEAT_AUX)) {
+                       struct iommu_group *group;
+
                        iommu_aux_detach_device(domain, iommu_device);
-               else
+                       group = iommu_group_get(dev);
+                       if (group) {
+                               iommu_group_set_domain(group, NULL);
+                               iommu_group_put(group);
+                       }
+               } else {
                        iommu_detach_device(domain, iommu_device);
+               }
        }
 
        return 0;
-- 
2.17.1

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