[PATCH V4 06/10] vfio: Introduce and set noiommu flag on vfio_device

[Jacob Pan <jacob.pan@linux.microsoft.com>]

When a VFIO device is added to a noiommu group, set the noiommu flag on
the vfio_device structure to indicate that the device operates in
noiommu mode.

Also update function signatures to pass vfio_device instead of device,
which has the direct access to the noiommu flag.

Reviewed-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Jacob Pan <jacob.pan@linux.microsoft.com>
---
v3:
   - Squashed with vfio noiommu logic check patch 7/11 of v2 (Mostafa)
---
 drivers/vfio/group.c | 21 +++++++++++----------
 drivers/vfio/vfio.h  |  3 +--
 include/linux/vfio.h |  1 +
 3 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c
index 451e49d851f8..b7009b44703b 100644
--- a/drivers/vfio/group.c
+++ b/drivers/vfio/group.c
@@ -597,7 +597,7 @@ static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group,
 	return ret;
 }
 
-static struct vfio_group *vfio_noiommu_group_alloc(struct device *dev,
+static struct vfio_group *vfio_noiommu_group_alloc(struct vfio_device *vdev,
 		enum vfio_group_type type)
 {
 	struct iommu_group *iommu_group;
@@ -619,7 +619,7 @@ static struct vfio_group *vfio_noiommu_group_alloc(struct device *dev,
 	ret = iommu_group_set_name(iommu_group, "vfio-noiommu");
 	if (ret)
 		goto out_put_group;
-	ret = iommu_group_add_device(iommu_group, dev);
+	ret = iommu_group_add_device(iommu_group, vdev->dev);
 	if (ret)
 		goto out_put_group;
 
@@ -634,7 +634,7 @@ static struct vfio_group *vfio_noiommu_group_alloc(struct device *dev,
 	return group;
 
 out_remove_device:
-	iommu_group_remove_device(dev);
+	iommu_group_remove_device(vdev->dev);
 out_put_group:
 	iommu_group_put(iommu_group);
 	return ERR_PTR(ret);
@@ -655,23 +655,24 @@ static bool vfio_group_has_device(struct vfio_group *group, struct device *dev)
 	return false;
 }
 
-static struct vfio_group *vfio_group_find_or_alloc(struct device *dev)
+static struct vfio_group *vfio_group_find_or_alloc(struct vfio_device *vdev)
 {
 	struct iommu_group *iommu_group;
 	struct vfio_group *group;
 
-	iommu_group = iommu_group_get(dev);
+	iommu_group = iommu_group_get(vdev->dev);
 	if (!iommu_group && vfio_noiommu) {
+		vdev->noiommu = 1;
 		/*
 		 * With noiommu enabled, create an IOMMU group for devices that
 		 * don't already have one, implying no IOMMU hardware/driver
 		 * exists.  Taint the kernel because we're about to give a DMA
 		 * capable device to a user without IOMMU protection.
 		 */
-		group = vfio_noiommu_group_alloc(dev, VFIO_NO_IOMMU);
+		group = vfio_noiommu_group_alloc(vdev, VFIO_NO_IOMMU);
 		if (!IS_ERR(group)) {
 			add_taint(TAINT_USER, LOCKDEP_STILL_OK);
-			dev_warn(dev, "Adding kernel taint for vfio-noiommu group on device\n");
+			dev_warn(vdev->dev, "Adding kernel taint for vfio-noiommu group on device\n");
 		}
 		return group;
 	}
@@ -682,7 +683,7 @@ static struct vfio_group *vfio_group_find_or_alloc(struct device *dev)
 	mutex_lock(&vfio.group_lock);
 	group = vfio_group_find_from_iommu(iommu_group);
 	if (group) {
-		if (WARN_ON(vfio_group_has_device(group, dev)))
+		if (WARN_ON(vfio_group_has_device(group, vdev->dev)))
 			group = ERR_PTR(-EINVAL);
 		else
 			refcount_inc(&group->drivers);
@@ -702,9 +703,9 @@ int vfio_device_set_group(struct vfio_device *device,
 	struct vfio_group *group;
 
 	if (type == VFIO_IOMMU)
-		group = vfio_group_find_or_alloc(device->dev);
+		group = vfio_group_find_or_alloc(device);
 	else
-		group = vfio_noiommu_group_alloc(device->dev, type);
+		group = vfio_noiommu_group_alloc(device, type);
 
 	if (IS_ERR(group))
 		return PTR_ERR(group);
diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
index db1530bb1716..9e25605da564 100644
--- a/drivers/vfio/vfio.h
+++ b/drivers/vfio/vfio.h
@@ -128,8 +128,7 @@ static inline bool vfio_null_group_allowed(void)
 
 static inline bool vfio_device_is_noiommu(struct vfio_device *vdev)
 {
-	return IS_ENABLED(CONFIG_VFIO_NOIOMMU) &&
-	       vdev->group->type == VFIO_NO_IOMMU;
+	return IS_ENABLED(CONFIG_VFIO_NOIOMMU) && vdev->noiommu;
 }
 #else
 struct vfio_group;
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index ceb5034c3a2e..502be18a1390 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -72,6 +72,7 @@ struct vfio_device {
 	u8 iommufd_attached:1;
 #endif
 	u8 cdev_opened:1;
+	u8 noiommu:1;
 #ifdef CONFIG_DEBUG_FS
 	/*
 	 * debug_root is a static property of the vfio_device
-- 
2.34.1