[PATCH 1/9] vfio: Make vfio_(un)register_notifier accept a vfio_device

[Jason Gunthorpe <jgg@nvidia.com>]

All callers have a struct vfio_device trivially available, pass it in
directly and avoid calling the expensive vfio_group_get_from_dev().

To support the unconverted kvmgt mdev driver add
mdev_legacy_get_vfio_device() which will return the vfio_device pointer
vfio_mdev.c puts in the drv_data.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/gpu/drm/i915/gvt/kvmgt.c  | 15 +++++++++------
 drivers/s390/cio/vfio_ccw_ops.c   |  7 +++----
 drivers/s390/crypto/vfio_ap_ops.c | 14 +++++++-------
 drivers/vfio/mdev/vfio_mdev.c     | 12 ++++++++++++
 drivers/vfio/vfio.c               | 25 +++++++------------------
 include/linux/mdev.h              |  1 +
 include/linux/vfio.h              |  4 ++--
 7 files changed, 41 insertions(+), 37 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 057ec449010458..bb59d21cf898ab 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -904,6 +904,7 @@ static int intel_vgpu_group_notifier(struct notifier_block *nb,
 
 static int intel_vgpu_open_device(struct mdev_device *mdev)
 {
+	struct vfio_device *vfio_dev = mdev_legacy_get_vfio_device(mdev);
 	struct intel_vgpu *vgpu = mdev_get_drvdata(mdev);
 	struct kvmgt_vdev *vdev = kvmgt_vdev(vgpu);
 	unsigned long events;
@@ -914,7 +915,7 @@ static int intel_vgpu_open_device(struct mdev_device *mdev)
 	vdev->group_notifier.notifier_call = intel_vgpu_group_notifier;
 
 	events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
-	ret = vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY, &events,
+	ret = vfio_register_notifier(vfio_dev, VFIO_IOMMU_NOTIFY, &events,
 				&vdev->iommu_notifier);
 	if (ret != 0) {
 		gvt_vgpu_err("vfio_register_notifier for iommu failed: %d\n",
@@ -923,7 +924,7 @@ static int intel_vgpu_open_device(struct mdev_device *mdev)
 	}
 
 	events = VFIO_GROUP_NOTIFY_SET_KVM;
-	ret = vfio_register_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY, &events,
+	ret = vfio_register_notifier(vfio_dev, VFIO_GROUP_NOTIFY, &events,
 				&vdev->group_notifier);
 	if (ret != 0) {
 		gvt_vgpu_err("vfio_register_notifier for group failed: %d\n",
@@ -961,11 +962,11 @@ static int intel_vgpu_open_device(struct mdev_device *mdev)
 	vdev->vfio_group = NULL;
 
 undo_register:
-	vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
+	vfio_unregister_notifier(vfio_dev, VFIO_GROUP_NOTIFY,
 					&vdev->group_notifier);
 
 undo_iommu:
-	vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
+	vfio_unregister_notifier(vfio_dev, VFIO_IOMMU_NOTIFY,
 					&vdev->iommu_notifier);
 out:
 	return ret;
@@ -988,6 +989,7 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu)
 	struct kvmgt_vdev *vdev = kvmgt_vdev(vgpu);
 	struct drm_i915_private *i915 = vgpu->gvt->gt->i915;
 	struct kvmgt_guest_info *info;
+	struct vfio_device *vfio_dev;
 	int ret;
 
 	if (!handle_valid(vgpu->handle))
@@ -998,12 +1000,13 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu)
 
 	intel_gvt_ops->vgpu_release(vgpu);
 
-	ret = vfio_unregister_notifier(mdev_dev(vdev->mdev), VFIO_IOMMU_NOTIFY,
+	vfio_dev = mdev_legacy_get_vfio_device(vdev->mdev);
+	ret = vfio_unregister_notifier(vfio_dev, VFIO_IOMMU_NOTIFY,
 					&vdev->iommu_notifier);
 	drm_WARN(&i915->drm, ret,
 		 "vfio_unregister_notifier for iommu failed: %d\n", ret);
 
-	ret = vfio_unregister_notifier(mdev_dev(vdev->mdev), VFIO_GROUP_NOTIFY,
+	ret = vfio_unregister_notifier(vfio_dev, VFIO_GROUP_NOTIFY,
 					&vdev->group_notifier);
 	drm_WARN(&i915->drm, ret,
 		 "vfio_unregister_notifier for group failed: %d\n", ret);
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index d8589afac272f1..e1ce24d8fb2555 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -183,7 +183,7 @@ static int vfio_ccw_mdev_open_device(struct vfio_device *vdev)
 
 	private->nb.notifier_call = vfio_ccw_mdev_notifier;
 
-	ret = vfio_register_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
+	ret = vfio_register_notifier(vdev, VFIO_IOMMU_NOTIFY,
 				     &events, &private->nb);
 	if (ret)
 		return ret;
@@ -204,8 +204,7 @@ static int vfio_ccw_mdev_open_device(struct vfio_device *vdev)
 
 out_unregister:
 	vfio_ccw_unregister_dev_regions(private);
-	vfio_unregister_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
-				 &private->nb);
+	vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY, &private->nb);
 	return ret;
 }
 
@@ -223,7 +222,7 @@ static void vfio_ccw_mdev_close_device(struct vfio_device *vdev)
 
 	cp_free(&private->cp);
 	vfio_ccw_unregister_dev_regions(private);
-	vfio_unregister_notifier(vdev->dev, VFIO_IOMMU_NOTIFY, &private->nb);
+	vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY, &private->nb);
 }
 
 static ssize_t vfio_ccw_mdev_read_io_region(struct vfio_ccw_private *private,
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 6e08d04b605d6e..69768061cd7bd9 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -1406,21 +1406,21 @@ static int vfio_ap_mdev_open_device(struct vfio_device *vdev)
 	matrix_mdev->group_notifier.notifier_call = vfio_ap_mdev_group_notifier;
 	events = VFIO_GROUP_NOTIFY_SET_KVM;
 
-	ret = vfio_register_notifier(vdev->dev, VFIO_GROUP_NOTIFY,
-				     &events, &matrix_mdev->group_notifier);
+	ret = vfio_register_notifier(vdev, VFIO_GROUP_NOTIFY, &events,
+				     &matrix_mdev->group_notifier);
 	if (ret)
 		return ret;
 
 	matrix_mdev->iommu_notifier.notifier_call = vfio_ap_mdev_iommu_notifier;
 	events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
-	ret = vfio_register_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
-				     &events, &matrix_mdev->iommu_notifier);
+	ret = vfio_register_notifier(vdev, VFIO_IOMMU_NOTIFY, &events,
+				     &matrix_mdev->iommu_notifier);
 	if (ret)
 		goto out_unregister_group;
 	return 0;
 
 out_unregister_group:
-	vfio_unregister_notifier(vdev->dev, VFIO_GROUP_NOTIFY,
+	vfio_unregister_notifier(vdev, VFIO_GROUP_NOTIFY,
 				 &matrix_mdev->group_notifier);
 	return ret;
 }
@@ -1430,9 +1430,9 @@ static void vfio_ap_mdev_close_device(struct vfio_device *vdev)
 	struct ap_matrix_mdev *matrix_mdev =
 		container_of(vdev, struct ap_matrix_mdev, vdev);
 
-	vfio_unregister_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
+	vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY,
 				 &matrix_mdev->iommu_notifier);
-	vfio_unregister_notifier(vdev->dev, VFIO_GROUP_NOTIFY,
+	vfio_unregister_notifier(vdev, VFIO_GROUP_NOTIFY,
 				 &matrix_mdev->group_notifier);
 	vfio_ap_mdev_unset_kvm(matrix_mdev);
 }
diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
index a90e24b0c851d3..91605c1e8c8f94 100644
--- a/drivers/vfio/mdev/vfio_mdev.c
+++ b/drivers/vfio/mdev/vfio_mdev.c
@@ -17,6 +17,18 @@
 
 #include "mdev_private.h"
 
+/*
+ * Return the struct vfio_device for the mdev when using the legacy
+ * vfio_mdev_dev_ops path. No new callers to this function should be added.
+ */
+struct vfio_device *mdev_legacy_get_vfio_device(struct mdev_device *mdev)
+{
+	if (WARN_ON(mdev->dev.driver != &vfio_mdev_driver.driver))
+		return NULL;
+	return dev_get_drvdata(&mdev->dev);
+}
+EXPORT_SYMBOL_GPL(mdev_legacy_get_vfio_device);
+
 static int vfio_mdev_open_device(struct vfio_device *core_vdev)
 {
 	struct mdev_device *mdev = to_mdev_device(core_vdev->dev);
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index a4555014bd1e72..8a5c46aa2bef61 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -2484,19 +2484,15 @@ static int vfio_unregister_group_notifier(struct vfio_group *group,
 	return ret;
 }
 
-int vfio_register_notifier(struct device *dev, enum vfio_notify_type type,
+int vfio_register_notifier(struct vfio_device *dev, enum vfio_notify_type type,
 			   unsigned long *events, struct notifier_block *nb)
 {
-	struct vfio_group *group;
+	struct vfio_group *group = dev->group;
 	int ret;
 
-	if (!dev || !nb || !events || (*events == 0))
+	if (!nb || !events || (*events == 0))
 		return -EINVAL;
 
-	group = vfio_group_get_from_dev(dev);
-	if (!group)
-		return -ENODEV;
-
 	switch (type) {
 	case VFIO_IOMMU_NOTIFY:
 		ret = vfio_register_iommu_notifier(group, events, nb);
@@ -2507,25 +2503,20 @@ int vfio_register_notifier(struct device *dev, enum vfio_notify_type type,
 	default:
 		ret = -EINVAL;
 	}
-
-	vfio_group_put(group);
 	return ret;
 }
 EXPORT_SYMBOL(vfio_register_notifier);
 
-int vfio_unregister_notifier(struct device *dev, enum vfio_notify_type type,
+int vfio_unregister_notifier(struct vfio_device *dev,
+			     enum vfio_notify_type type,
 			     struct notifier_block *nb)
 {
-	struct vfio_group *group;
+	struct vfio_group *group = dev->group;
 	int ret;
 
-	if (!dev || !nb)
+	if (!nb)
 		return -EINVAL;
 
-	group = vfio_group_get_from_dev(dev);
-	if (!group)
-		return -ENODEV;
-
 	switch (type) {
 	case VFIO_IOMMU_NOTIFY:
 		ret = vfio_unregister_iommu_notifier(group, nb);
@@ -2536,8 +2527,6 @@ int vfio_unregister_notifier(struct device *dev, enum vfio_notify_type type,
 	default:
 		ret = -EINVAL;
 	}
-
-	vfio_group_put(group);
 	return ret;
 }
 EXPORT_SYMBOL(vfio_unregister_notifier);
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 15d03f6532d073..67d07220a28f29 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -29,6 +29,7 @@ static inline struct mdev_device *to_mdev_device(struct device *dev)
 unsigned int mdev_get_type_group_id(struct mdev_device *mdev);
 unsigned int mtype_get_type_group_id(struct mdev_type *mtype);
 struct device *mtype_get_parent_dev(struct mdev_type *mtype);
+struct vfio_device *mdev_legacy_get_vfio_device(struct mdev_device *mdev);
 
 /**
  * struct mdev_parent_ops - Structure to be registered for each parent device to
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 66dda06ec42d1b..748ec0e0293aea 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -178,11 +178,11 @@ enum vfio_notify_type {
 /* events for VFIO_GROUP_NOTIFY */
 #define VFIO_GROUP_NOTIFY_SET_KVM	BIT(0)
 
-extern int vfio_register_notifier(struct device *dev,
+extern int vfio_register_notifier(struct vfio_device *dev,
 				  enum vfio_notify_type type,
 				  unsigned long *required_events,
 				  struct notifier_block *nb);
-extern int vfio_unregister_notifier(struct device *dev,
+extern int vfio_unregister_notifier(struct vfio_device *dev,
 				    enum vfio_notify_type type,
 				    struct notifier_block *nb);
 
-- 
2.35.1