Merge tag 'vfio-v6.1-rc1' of https://github.com/awilliam/linux-vfio

Pull VFIO updates from Alex Williamson:

 - Prune private items from vfio_pci_core.h to a new internal header,
   fix missed function rename, and refactor vfio-pci interrupt defines
   (Jason Gunthorpe)

 - Create consistent naming and handling of ioctls with a function per
   ioctl for vfio-pci and vfio group handling, use proper type args
   where available (Jason Gunthorpe)

 - Implement a set of low power device feature ioctls allowing userspace
   to make use of power states such as D3cold where supported (Abhishek
   Sahu)

 - Remove device counter on vfio groups, which had restricted the page
   pinning interface to singleton groups to account for limitations in
   the type1 IOMMU backend. Document usage as limited to emulated IOMMU
   devices, ie. traditional mdev devices where this restriction is
   consistent (Jason Gunthorpe)

 - Correct function prefix in hisi_acc driver incurred during previous
   refactoring (Shameer Kolothum)

 - Correct typo and remove redundant warning triggers in vfio-fsl driver
   (Christophe JAILLET)

 - Introduce device level DMA dirty tracking uAPI and implementation in
   the mlx5 variant driver (Yishai Hadas & Joao Martins)

 - Move much of the vfio_device life cycle management into vfio core,
   simplifying and avoiding duplication across drivers. This also
   facilitates adding a struct device to vfio_device which begins the
   introduction of device rather than group level user support and fills
   a gap allowing userspace identify devices as vfio capable without
   implicit knowledge of the driver (Kevin Tian & Yi Liu)

 - Split vfio container handling to a separate file, creating a more
   well defined API between the core and container code, masking IOMMU
   backend implementation from the core, allowing for an easier future
   transition to an iommufd based implementation of the same (Jason
   Gunthorpe)

 - Attempt to resolve race accessing the iommu_group for a device
   between vfio releasing DMA ownership and removal of the device from
   the IOMMU driver. Follow-up with support to allow vfio_group to exist
   with NULL iommu_group pointer to support existing userspace use cases
   of holding the group file open (Jason Gunthorpe)

 - Fix error code and hi/lo register manipulation issues in the hisi_acc
   variant driver, along with various code cleanups (Longfang Liu)

 - Fix a prior regression in GVT-g group teardown, resulting in
   unreleased resources (Jason Gunthorpe)

 - A significant cleanup and simplification of the mdev interface,
   consolidating much of the open coded per driver sysfs interface
   support into the mdev core (Christoph Hellwig)

 - Simplification of tracking and locking around vfio_groups that fall
   out from previous refactoring (Jason Gunthorpe)

 - Replace trivial open coded f_ops tests with new helper (Alex
   Williamson)

* tag 'vfio-v6.1-rc1' of https://github.com/awilliam/linux-vfio: (77 commits)
  vfio: More vfio_file_is_group() use cases
  vfio: Make the group FD disassociate from the iommu_group
  vfio: Hold a reference to the iommu_group in kvm for SPAPR
  vfio: Add vfio_file_is_group()
  vfio: Change vfio_group->group_rwsem to a mutex
  vfio: Remove the vfio_group->users and users_comp
  vfio/mdev: add mdev available instance checking to the core
  vfio/mdev: consolidate all the description sysfs into the core code
  vfio/mdev: consolidate all the available_instance sysfs into the core code
  vfio/mdev: consolidate all the name sysfs into the core code
  vfio/mdev: consolidate all the device_api sysfs into the core code
  vfio/mdev: remove mtype_get_parent_dev
  vfio/mdev: remove mdev_parent_dev
  vfio/mdev: unexport mdev_bus_type
  vfio/mdev: remove mdev_from_dev
  vfio/mdev: simplify mdev_type handling
  vfio/mdev: embedd struct mdev_parent in the parent data structure
  vfio/mdev: make mdev.h standalone includable
  drm/i915/gvt: simplify vgpu configuration management
  drm/i915/gvt: fix a memory leak in intel_gvt_init_vgpu_types
  ...

3 files changed, 217 insertions, 297 deletions

diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index 344c2901a82b..117a8d799f71 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -21,7 +21,6 @@
  */
 #include <linux/init.h>
 #include <linux/module.h>
-#include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
@@ -100,35 +99,44 @@ MODULE_PARM_DESC(mem, "megabytes available to " MBOCHS_NAME " devices");
 #define MBOCHS_TYPE_2 "medium"
 #define MBOCHS_TYPE_3 "large"
 
-static const struct mbochs_type {
-	const char *name;
+static struct mbochs_type {
+	struct mdev_type type;
 	u32 mbytes;
 	u32 max_x;
 	u32 max_y;
 } mbochs_types[] = {
 	{
-		.name	= MBOCHS_CLASS_NAME "-" MBOCHS_TYPE_1,
+		.type.sysfs_name	= MBOCHS_TYPE_1,
+		.type.pretty_name	= MBOCHS_CLASS_NAME "-" MBOCHS_TYPE_1,
 		.mbytes = 4,
 		.max_x  = 800,
 		.max_y  = 600,
 	}, {
-		.name	= MBOCHS_CLASS_NAME "-" MBOCHS_TYPE_2,
+		.type.sysfs_name	= MBOCHS_TYPE_2,
+		.type.pretty_name	= MBOCHS_CLASS_NAME "-" MBOCHS_TYPE_2,
 		.mbytes = 16,
 		.max_x  = 1920,
 		.max_y  = 1440,
 	}, {
-		.name	= MBOCHS_CLASS_NAME "-" MBOCHS_TYPE_3,
+		.type.sysfs_name	= MBOCHS_TYPE_3,
+		.type.pretty_name	= MBOCHS_CLASS_NAME "-" MBOCHS_TYPE_3,
 		.mbytes = 64,
 		.max_x  = 0,
 		.max_y  = 0,
 	},
 };
 
+static struct mdev_type *mbochs_mdev_types[] = {
+	&mbochs_types[0].type,
+	&mbochs_types[1].type,
+	&mbochs_types[2].type,
+};
 
 static dev_t		mbochs_devt;
 static struct class	*mbochs_class;
 static struct cdev	mbochs_cdev;
 static struct device	mbochs_dev;
+static struct mdev_parent mbochs_parent;
 static atomic_t mbochs_avail_mbytes;
 static const struct vfio_device_ops mbochs_dev_ops;
 
@@ -505,13 +513,14 @@ static int mbochs_reset(struct mdev_state *mdev_state)
 	return 0;
 }
 
-static int mbochs_probe(struct mdev_device *mdev)
+static int mbochs_init_dev(struct vfio_device *vdev)
 {
+	struct mdev_state *mdev_state =
+		container_of(vdev, struct mdev_state, vdev);
+	struct mdev_device *mdev = to_mdev_device(vdev->dev);
+	struct mbochs_type *type =
+		container_of(mdev->type, struct mbochs_type, type);
 	int avail_mbytes = atomic_read(&mbochs_avail_mbytes);
-	const struct mbochs_type *type =
-		&mbochs_types[mdev_get_type_group_id(mdev)];
-	struct device *dev = mdev_dev(mdev);
-	struct mdev_state *mdev_state;
 	int ret = -ENOMEM;
 
 	do {
@@ -520,14 +529,9 @@ static int mbochs_probe(struct mdev_device *mdev)
 	} while (!atomic_try_cmpxchg(&mbochs_avail_mbytes, &avail_mbytes,
 				     avail_mbytes - type->mbytes));
 
-	mdev_state = kzalloc(sizeof(struct mdev_state), GFP_KERNEL);
-	if (mdev_state == NULL)
-		goto err_avail;
-	vfio_init_group_dev(&mdev_state->vdev, &mdev->dev, &mbochs_dev_ops);
-
 	mdev_state->vconfig = kzalloc(MBOCHS_CONFIG_SPACE_SIZE, GFP_KERNEL);
-	if (mdev_state->vconfig == NULL)
-		goto err_mem;
+	if (!mdev_state->vconfig)
+		goto err_avail;
 
 	mdev_state->memsize = type->mbytes * 1024 * 1024;
 	mdev_state->pagecount = mdev_state->memsize >> PAGE_SHIFT;
@@ -535,10 +539,7 @@ static int mbochs_probe(struct mdev_device *mdev)
 				    sizeof(struct page *),
 				    GFP_KERNEL);
 	if (!mdev_state->pages)
-		goto err_mem;
-
-	dev_info(dev, "%s: %s, %d MB, %ld pages\n", __func__,
-		 type->name, type->mbytes, mdev_state->pagecount);
+		goto err_vconfig;
 
 	mutex_init(&mdev_state->ops_lock);
 	mdev_state->mdev = mdev;
@@ -553,19 +554,47 @@ static int mbochs_probe(struct mdev_device *mdev)
 	mbochs_create_config_space(mdev_state);
 	mbochs_reset(mdev_state);
 
+	dev_info(vdev->dev, "%s: %s, %d MB, %ld pages\n", __func__,
+		 type->type.pretty_name, type->mbytes, mdev_state->pagecount);
+	return 0;
+
+err_vconfig:
+	kfree(mdev_state->vconfig);
+err_avail:
+	atomic_add(type->mbytes, &mbochs_avail_mbytes);
+	return ret;
+}
+
+static int mbochs_probe(struct mdev_device *mdev)
+{
+	struct mdev_state *mdev_state;
+	int ret = -ENOMEM;
+
+	mdev_state = vfio_alloc_device(mdev_state, vdev, &mdev->dev,
+				       &mbochs_dev_ops);
+	if (IS_ERR(mdev_state))
+		return PTR_ERR(mdev_state);
+
 	ret = vfio_register_emulated_iommu_dev(&mdev_state->vdev);
 	if (ret)
-		goto err_mem;
+		goto err_put_vdev;
 	dev_set_drvdata(&mdev->dev, mdev_state);
 	return 0;
-err_mem:
-	vfio_uninit_group_dev(&mdev_state->vdev);
+
+err_put_vdev:
+	vfio_put_device(&mdev_state->vdev);
+	return ret;
+}
+
+static void mbochs_release_dev(struct vfio_device *vdev)
+{
+	struct mdev_state *mdev_state =
+		container_of(vdev, struct mdev_state, vdev);
+
+	atomic_add(mdev_state->type->mbytes, &mbochs_avail_mbytes);
 	kfree(mdev_state->pages);
 	kfree(mdev_state->vconfig);
-	kfree(mdev_state);
-err_avail:
-	atomic_add(type->mbytes, &mbochs_avail_mbytes);
-	return ret;
+	vfio_free_device(vdev);
 }
 
 static void mbochs_remove(struct mdev_device *mdev)
@@ -573,11 +602,7 @@ static void mbochs_remove(struct mdev_device *mdev)
 	struct mdev_state *mdev_state = dev_get_drvdata(&mdev->dev);
 
 	vfio_unregister_group_dev(&mdev_state->vdev);
-	vfio_uninit_group_dev(&mdev_state->vdev);
-	atomic_add(mdev_state->type->mbytes, &mbochs_avail_mbytes);
-	kfree(mdev_state->pages);
-	kfree(mdev_state->vconfig);
-	kfree(mdev_state);
+	vfio_put_device(&mdev_state->vdev);
 }
 
 static ssize_t mbochs_read(struct vfio_device *vdev, char __user *buf,
@@ -1325,78 +1350,27 @@ static const struct attribute_group *mdev_dev_groups[] = {
 	NULL,
 };
 
-static ssize_t name_show(struct mdev_type *mtype,
-			 struct mdev_type_attribute *attr, char *buf)
+static ssize_t mbochs_show_description(struct mdev_type *mtype, char *buf)
 {
-	const struct mbochs_type *type =
-		&mbochs_types[mtype_get_type_group_id(mtype)];
-
-	return sprintf(buf, "%s\n", type->name);
-}
-static MDEV_TYPE_ATTR_RO(name);
-
-static ssize_t description_show(struct mdev_type *mtype,
-				struct mdev_type_attribute *attr, char *buf)
-{
-	const struct mbochs_type *type =
-		&mbochs_types[mtype_get_type_group_id(mtype)];
+	struct mbochs_type *type =
+		container_of(mtype, struct mbochs_type, type);
 
 	return sprintf(buf, "virtual display, %d MB video memory\n",
 		       type ? type->mbytes  : 0);
 }
-static MDEV_TYPE_ATTR_RO(description);
 
-static ssize_t available_instances_show(struct mdev_type *mtype,
-					struct mdev_type_attribute *attr,
-					char *buf)
+static unsigned int mbochs_get_available(struct mdev_type *mtype)
 {
-	const struct mbochs_type *type =
-		&mbochs_types[mtype_get_type_group_id(mtype)];
-	int count = atomic_read(&mbochs_avail_mbytes) / type->mbytes;
-
-	return sprintf(buf, "%d\n", count);
-}
-static MDEV_TYPE_ATTR_RO(available_instances);
+	struct mbochs_type *type =
+		container_of(mtype, struct mbochs_type, type);
 
-static ssize_t device_api_show(struct mdev_type *mtype,
-			       struct mdev_type_attribute *attr, char *buf)
-{
-	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
+	return atomic_read(&mbochs_avail_mbytes) / type->mbytes;
 }
-static MDEV_TYPE_ATTR_RO(device_api);
-
-static struct attribute *mdev_types_attrs[] = {
-	&mdev_type_attr_name.attr,
-	&mdev_type_attr_description.attr,
-	&mdev_type_attr_device_api.attr,
-	&mdev_type_attr_available_instances.attr,
-	NULL,
-};
-
-static struct attribute_group mdev_type_group1 = {
-	.name  = MBOCHS_TYPE_1,
-	.attrs = mdev_types_attrs,
-};
-
-static struct attribute_group mdev_type_group2 = {
-	.name  = MBOCHS_TYPE_2,
-	.attrs = mdev_types_attrs,
-};
-
-static struct attribute_group mdev_type_group3 = {
-	.name  = MBOCHS_TYPE_3,
-	.attrs = mdev_types_attrs,
-};
-
-static struct attribute_group *mdev_type_groups[] = {
-	&mdev_type_group1,
-	&mdev_type_group2,
-	&mdev_type_group3,
-	NULL,
-};
 
 static const struct vfio_device_ops mbochs_dev_ops = {
 	.close_device = mbochs_close_device,
+	.init = mbochs_init_dev,
+	.release = mbochs_release_dev,
 	.read = mbochs_read,
 	.write = mbochs_write,
 	.ioctl = mbochs_ioctl,
@@ -1404,6 +1378,7 @@ static const struct vfio_device_ops mbochs_dev_ops = {
 };
 
 static struct mdev_driver mbochs_driver = {
+	.device_api = VFIO_DEVICE_API_PCI_STRING,
 	.driver = {
 		.name = "mbochs",
 		.owner = THIS_MODULE,
@@ -1412,7 +1387,8 @@ static struct mdev_driver mbochs_driver = {
 	},
 	.probe = mbochs_probe,
 	.remove	= mbochs_remove,
-	.supported_type_groups = mdev_type_groups,
+	.get_available = mbochs_get_available,
+	.show_description = mbochs_show_description,
 };
 
 static const struct file_operations vd_fops = {
@@ -1457,7 +1433,9 @@ static int __init mbochs_dev_init(void)
 	if (ret)
 		goto err_class;
 
-	ret = mdev_register_device(&mbochs_dev, &mbochs_driver);
+	ret = mdev_register_parent(&mbochs_parent, &mbochs_dev, &mbochs_driver,
+				   mbochs_mdev_types,
+				   ARRAY_SIZE(mbochs_mdev_types));
 	if (ret)
 		goto err_device;
 
@@ -1478,7 +1456,7 @@ err_cdev:
 static void __exit mbochs_dev_exit(void)
 {
 	mbochs_dev.bus = NULL;
-	mdev_unregister_device(&mbochs_dev);
+	mdev_unregister_parent(&mbochs_parent);
 
 	device_unregister(&mbochs_dev);
 	mdev_unregister_driver(&mbochs_driver);
diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
index e8c46eb2e246..946e8cfde6fd 100644
--- a/samples/vfio-mdev/mdpy.c
+++ b/samples/vfio-mdev/mdpy.c
@@ -17,7 +17,6 @@
  */
 #include <linux/init.h>
 #include <linux/module.h>
-#include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
@@ -43,36 +42,34 @@
 
 MODULE_LICENSE("GPL v2");
 
-static int max_devices = 4;
-module_param_named(count, max_devices, int, 0444);
-MODULE_PARM_DESC(count, "number of " MDPY_NAME " devices");
-
-
 #define MDPY_TYPE_1 "vga"
 #define MDPY_TYPE_2 "xga"
 #define MDPY_TYPE_3 "hd"
 
-static const struct mdpy_type {
-	const char *name;
+static struct mdpy_type {
+	struct mdev_type type;
 	u32 format;
 	u32 bytepp;
 	u32 width;
 	u32 height;
 } mdpy_types[] = {
 	{
-		.name	= MDPY_CLASS_NAME "-" MDPY_TYPE_1,
+		.type.sysfs_name 	= MDPY_TYPE_1,
+		.type.pretty_name	= MDPY_CLASS_NAME "-" MDPY_TYPE_1,
 		.format = DRM_FORMAT_XRGB8888,
 		.bytepp = 4,
 		.width	= 640,
 		.height = 480,
 	}, {
-		.name	= MDPY_CLASS_NAME "-" MDPY_TYPE_2,
+		.type.sysfs_name 	= MDPY_TYPE_2,
+		.type.pretty_name	= MDPY_CLASS_NAME "-" MDPY_TYPE_2,
 		.format = DRM_FORMAT_XRGB8888,
 		.bytepp = 4,
 		.width	= 1024,
 		.height = 768,
 	}, {
-		.name	= MDPY_CLASS_NAME "-" MDPY_TYPE_3,
+		.type.sysfs_name 	= MDPY_TYPE_3,
+		.type.pretty_name	= MDPY_CLASS_NAME "-" MDPY_TYPE_3,
 		.format = DRM_FORMAT_XRGB8888,
 		.bytepp = 4,
 		.width	= 1920,
@@ -80,11 +77,17 @@ static const struct mdpy_type {
 	},
 };
 
+static struct mdev_type *mdpy_mdev_types[] = {
+	&mdpy_types[0].type,
+	&mdpy_types[1].type,
+	&mdpy_types[2].type,
+};
+
 static dev_t		mdpy_devt;
 static struct class	*mdpy_class;
 static struct cdev	mdpy_cdev;
 static struct device	mdpy_dev;
-static u32		mdpy_count;
+static struct mdev_parent mdpy_parent;
 static const struct vfio_device_ops mdpy_dev_ops;
 
 /* State of each mdev device */
@@ -216,61 +219,71 @@ static int mdpy_reset(struct mdev_state *mdev_state)
 	return 0;
 }
 
-static int mdpy_probe(struct mdev_device *mdev)
+static int mdpy_init_dev(struct vfio_device *vdev)
 {
+	struct mdev_state *mdev_state =
+		container_of(vdev, struct mdev_state, vdev);
+	struct mdev_device *mdev = to_mdev_device(vdev->dev);
 	const struct mdpy_type *type =
-		&mdpy_types[mdev_get_type_group_id(mdev)];
-	struct device *dev = mdev_dev(mdev);
-	struct mdev_state *mdev_state;
+		container_of(mdev->type, struct mdpy_type, type);
 	u32 fbsize;
-	int ret;
-
-	if (mdpy_count >= max_devices)
-		return -ENOMEM;
-
-	mdev_state = kzalloc(sizeof(struct mdev_state), GFP_KERNEL);
-	if (mdev_state == NULL)
-		return -ENOMEM;
-	vfio_init_group_dev(&mdev_state->vdev, &mdev->dev, &mdpy_dev_ops);
+	int ret = -ENOMEM;
 
 	mdev_state->vconfig = kzalloc(MDPY_CONFIG_SPACE_SIZE, GFP_KERNEL);
-	if (mdev_state->vconfig == NULL) {
-		ret = -ENOMEM;
-		goto err_state;
-	}
+	if (!mdev_state->vconfig)
+		return ret;
 
 	fbsize = roundup_pow_of_two(type->width * type->height * type->bytepp);
 
 	mdev_state->memblk = vmalloc_user(fbsize);
-	if (!mdev_state->memblk) {
-		ret = -ENOMEM;
-		goto err_vconfig;
-	}
-	dev_info(dev, "%s: %s (%dx%d)\n", __func__, type->name, type->width,
-		 type->height);
+	if (!mdev_state->memblk)
+		goto out_vconfig;
 
 	mutex_init(&mdev_state->ops_lock);
 	mdev_state->mdev = mdev;
-	mdev_state->type    = type;
+	mdev_state->type = type;
 	mdev_state->memsize = fbsize;
 	mdpy_create_config_space(mdev_state);
 	mdpy_reset(mdev_state);
 
-	mdpy_count++;
+	dev_info(vdev->dev, "%s: %s (%dx%d)\n", __func__, type->type.pretty_name,
+		 type->width, type->height);
+	return 0;
+
+out_vconfig:
+	kfree(mdev_state->vconfig);
+	return ret;
+}
+
+static int mdpy_probe(struct mdev_device *mdev)
+{
+	struct mdev_state *mdev_state;
+	int ret;
+
+	mdev_state = vfio_alloc_device(mdev_state, vdev, &mdev->dev,
+				       &mdpy_dev_ops);
+	if (IS_ERR(mdev_state))
+		return PTR_ERR(mdev_state);
 
 	ret = vfio_register_emulated_iommu_dev(&mdev_state->vdev);
 	if (ret)
-		goto err_mem;
+		goto err_put_vdev;
 	dev_set_drvdata(&mdev->dev, mdev_state);
 	return 0;
-err_mem:
+
+err_put_vdev:
+	vfio_put_device(&mdev_state->vdev);
+	return ret;
+}
+
+static void mdpy_release_dev(struct vfio_device *vdev)
+{
+	struct mdev_state *mdev_state =
+		container_of(vdev, struct mdev_state, vdev);
+
 	vfree(mdev_state->memblk);
-err_vconfig:
 	kfree(mdev_state->vconfig);
-err_state:
-	vfio_uninit_group_dev(&mdev_state->vdev);
-	kfree(mdev_state);
-	return ret;
+	vfio_free_device(vdev);
 }
 
 static void mdpy_remove(struct mdev_device *mdev)
@@ -280,12 +293,7 @@ static void mdpy_remove(struct mdev_device *mdev)
 	dev_info(&mdev->dev, "%s\n", __func__);
 
 	vfio_unregister_group_dev(&mdev_state->vdev);
-	vfree(mdev_state->memblk);
-	kfree(mdev_state->vconfig);
-	vfio_uninit_group_dev(&mdev_state->vdev);
-	kfree(mdev_state);
-
-	mdpy_count--;
+	vfio_put_device(&mdev_state->vdev);
 }
 
 static ssize_t mdpy_read(struct vfio_device *vdev, char __user *buf,
@@ -641,73 +649,17 @@ static const struct attribute_group *mdev_dev_groups[] = {
 	NULL,
 };
 
-static ssize_t name_show(struct mdev_type *mtype,
-			 struct mdev_type_attribute *attr, char *buf)
-{
-	const struct mdpy_type *type =
-		&mdpy_types[mtype_get_type_group_id(mtype)];
-
-	return sprintf(buf, "%s\n", type->name);
-}
-static MDEV_TYPE_ATTR_RO(name);
-
-static ssize_t description_show(struct mdev_type *mtype,
-				struct mdev_type_attribute *attr, char *buf)
+static ssize_t mdpy_show_description(struct mdev_type *mtype, char *buf)
 {
-	const struct mdpy_type *type =
-		&mdpy_types[mtype_get_type_group_id(mtype)];
+	struct mdpy_type *type = container_of(mtype, struct mdpy_type, type);
 
 	return sprintf(buf, "virtual display, %dx%d framebuffer\n",
 		       type->width, type->height);
 }
-static MDEV_TYPE_ATTR_RO(description);
-
-static ssize_t available_instances_show(struct mdev_type *mtype,
-					struct mdev_type_attribute *attr,
-					char *buf)
-{
-	return sprintf(buf, "%d\n", max_devices - mdpy_count);
-}
-static MDEV_TYPE_ATTR_RO(available_instances);
-
-static ssize_t device_api_show(struct mdev_type *mtype,
-			       struct mdev_type_attribute *attr, char *buf)
-{
-	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
-}
-static MDEV_TYPE_ATTR_RO(device_api);
-
-static struct attribute *mdev_types_attrs[] = {
-	&mdev_type_attr_name.attr,
-	&mdev_type_attr_description.attr,
-	&mdev_type_attr_device_api.attr,
-	&mdev_type_attr_available_instances.attr,
-	NULL,
-};
-
-static struct attribute_group mdev_type_group1 = {
-	.name  = MDPY_TYPE_1,
-	.attrs = mdev_types_attrs,
-};
-
-static struct attribute_group mdev_type_group2 = {
-	.name  = MDPY_TYPE_2,
-	.attrs = mdev_types_attrs,
-};
-
-static struct attribute_group mdev_type_group3 = {
-	.name  = MDPY_TYPE_3,
-	.attrs = mdev_types_attrs,
-};
-
-static struct attribute_group *mdev_type_groups[] = {
-	&mdev_type_group1,
-	&mdev_type_group2,
-	&mdev_type_group3,
-	NULL,
-};
 
 static const struct vfio_device_ops mdpy_dev_ops = {
+	.init = mdpy_init_dev,
+	.release = mdpy_release_dev,
 	.read = mdpy_read,
 	.write = mdpy_write,
 	.ioctl = mdpy_ioctl,
@@ -715,6 +667,8 @@ static const struct vfio_device_ops mdpy_dev_ops = {
 };
 
 static struct mdev_driver mdpy_driver = {
+	.device_api = VFIO_DEVICE_API_PCI_STRING,
+	.max_instances = 4,
 	.driver = {
 		.name = "mdpy",
 		.owner = THIS_MODULE,
@@ -723,7 +677,7 @@ static struct mdev_driver mdpy_driver = {
 	},
 	.probe = mdpy_probe,
 	.remove	= mdpy_remove,
-	.supported_type_groups = mdev_type_groups,
+	.show_description = mdpy_show_description,
 };
 
 static const struct file_operations vd_fops = {
@@ -766,7 +720,9 @@ static int __init mdpy_dev_init(void)
 	if (ret)
 		goto err_class;
 
-	ret = mdev_register_device(&mdpy_dev, &mdpy_driver);
+	ret = mdev_register_parent(&mdpy_parent, &mdpy_dev, &mdpy_driver,
+				   mdpy_mdev_types,
+				   ARRAY_SIZE(mdpy_mdev_types));
 	if (ret)
 		goto err_device;
 
@@ -787,7 +743,7 @@ err_cdev:
 static void __exit mdpy_dev_exit(void)
 {
 	mdpy_dev.bus = NULL;
-	mdev_unregister_device(&mdpy_dev);
+	mdev_unregister_parent(&mdpy_parent);
 
 	device_unregister(&mdpy_dev);
 	mdev_unregister_driver(&mdpy_driver);
@@ -797,5 +753,8 @@ static void __exit mdpy_dev_exit(void)
 	mdpy_class = NULL;
 }
 
+module_param_named(count, mdpy_driver.max_instances, int, 0444);
+MODULE_PARM_DESC(count, "number of " MDPY_NAME " devices");
+
 module_init(mdpy_dev_init)
 module_exit(mdpy_dev_exit)
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index f42a59ed2e3f..e72085fc1376 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -12,7 +12,6 @@
 
 #include <linux/init.h>
 #include <linux/module.h>
-#include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/fs.h>
 #include <linux/poll.h>
@@ -20,7 +19,6 @@
 #include <linux/cdev.h>
 #include <linux/sched.h>
 #include <linux/wait.h>
-#include <linux/uuid.h>
 #include <linux/vfio.h>
 #include <linux/iommu.h>
 #include <linux/sysfs.h>
@@ -74,6 +72,7 @@ static struct mtty_dev {
 	struct cdev	vd_cdev;
 	struct idr	vd_idr;
 	struct device	dev;
+	struct mdev_parent parent;
 } mtty_dev;
 
 struct mdev_region_info {
@@ -144,6 +143,21 @@ struct mdev_state {
 	int nr_ports;
 };
 
+static struct mtty_type {
+	struct mdev_type type;
+	int nr_ports;
+} mtty_types[2] = {
+	{ .nr_ports = 1, .type.sysfs_name = "1",
+	  .type.pretty_name = "Single port serial" },
+	{ .nr_ports = 2, .type.sysfs_name = "2",
+	  .type.pretty_name = "Dual port serial" },
+};
+
+static struct mdev_type *mtty_mdev_types[] = {
+	&mtty_types[0].type,
+	&mtty_types[1].type,
+};
+
 static atomic_t mdev_avail_ports = ATOMIC_INIT(MAX_MTTYS);
 
 static const struct file_operations vd_fops = {
@@ -703,71 +717,82 @@ accessfailed:
 	return ret;
 }
 
-static int mtty_probe(struct mdev_device *mdev)
+static int mtty_init_dev(struct vfio_device *vdev)
 {
-	struct mdev_state *mdev_state;
-	int nr_ports = mdev_get_type_group_id(mdev) + 1;
+	struct mdev_state *mdev_state =
+		container_of(vdev, struct mdev_state, vdev);
+	struct mdev_device *mdev = to_mdev_device(vdev->dev);
+	struct mtty_type *type =
+		container_of(mdev->type, struct mtty_type, type);
 	int avail_ports = atomic_read(&mdev_avail_ports);
 	int ret;
 
 	do {
-		if (avail_ports < nr_ports)
+		if (avail_ports < type->nr_ports)
 			return -ENOSPC;
 	} while (!atomic_try_cmpxchg(&mdev_avail_ports,
-				     &avail_ports, avail_ports - nr_ports));
+				     &avail_ports,
+				     avail_ports - type->nr_ports));
 
-	mdev_state = kzalloc(sizeof(struct mdev_state), GFP_KERNEL);
-	if (mdev_state == NULL) {
-		ret = -ENOMEM;
-		goto err_nr_ports;
-	}
-
-	vfio_init_group_dev(&mdev_state->vdev, &mdev->dev, &mtty_dev_ops);
-
-	mdev_state->nr_ports = nr_ports;
+	mdev_state->nr_ports = type->nr_ports;
 	mdev_state->irq_index = -1;
 	mdev_state->s[0].max_fifo_size = MAX_FIFO_SIZE;
 	mdev_state->s[1].max_fifo_size = MAX_FIFO_SIZE;
 	mutex_init(&mdev_state->rxtx_lock);
-	mdev_state->vconfig = kzalloc(MTTY_CONFIG_SPACE_SIZE, GFP_KERNEL);
 
-	if (mdev_state->vconfig == NULL) {
+	mdev_state->vconfig = kzalloc(MTTY_CONFIG_SPACE_SIZE, GFP_KERNEL);
+	if (!mdev_state->vconfig) {
 		ret = -ENOMEM;
-		goto err_state;
+		goto err_nr_ports;
 	}
 
 	mutex_init(&mdev_state->ops_lock);
 	mdev_state->mdev = mdev;
-
 	mtty_create_config_space(mdev_state);
+	return 0;
+
+err_nr_ports:
+	atomic_add(type->nr_ports, &mdev_avail_ports);
+	return ret;
+}
+
+static int mtty_probe(struct mdev_device *mdev)
+{
+	struct mdev_state *mdev_state;
+	int ret;
+
+	mdev_state = vfio_alloc_device(mdev_state, vdev, &mdev->dev,
+				       &mtty_dev_ops);
+	if (IS_ERR(mdev_state))
+		return PTR_ERR(mdev_state);
 
 	ret = vfio_register_emulated_iommu_dev(&mdev_state->vdev);
 	if (ret)
-		goto err_vconfig;
+		goto err_put_vdev;
 	dev_set_drvdata(&mdev->dev, mdev_state);
 	return 0;
 
-err_vconfig:
-	kfree(mdev_state->vconfig);
-err_state:
-	vfio_uninit_group_dev(&mdev_state->vdev);
-	kfree(mdev_state);
-err_nr_ports:
-	atomic_add(nr_ports, &mdev_avail_ports);
+err_put_vdev:
+	vfio_put_device(&mdev_state->vdev);
 	return ret;
 }
 
+static void mtty_release_dev(struct vfio_device *vdev)
+{
+	struct mdev_state *mdev_state =
+		container_of(vdev, struct mdev_state, vdev);
+
+	atomic_add(mdev_state->nr_ports, &mdev_avail_ports);
+	kfree(mdev_state->vconfig);
+	vfio_free_device(vdev);
+}
+
 static void mtty_remove(struct mdev_device *mdev)
 {
 	struct mdev_state *mdev_state = dev_get_drvdata(&mdev->dev);
-	int nr_ports = mdev_state->nr_ports;
 
 	vfio_unregister_group_dev(&mdev_state->vdev);
-
-	kfree(mdev_state->vconfig);
-	vfio_uninit_group_dev(&mdev_state->vdev);
-	kfree(mdev_state);
-	atomic_add(nr_ports, &mdev_avail_ports);
+	vfio_put_device(&mdev_state->vdev);
 }
 
 static int mtty_reset(struct mdev_state *mdev_state)
@@ -1231,68 +1256,24 @@ static const struct attribute_group *mdev_dev_groups[] = {
 	NULL,
 };
 
-static ssize_t name_show(struct mdev_type *mtype,
-			 struct mdev_type_attribute *attr, char *buf)
-{
-	static const char *name_str[2] = { "Single port serial",
-					   "Dual port serial" };
-
-	return sysfs_emit(buf, "%s\n",
-			  name_str[mtype_get_type_group_id(mtype)]);
-}
-
-static MDEV_TYPE_ATTR_RO(name);
-
-static ssize_t available_instances_show(struct mdev_type *mtype,
-					struct mdev_type_attribute *attr,
-					char *buf)
+static unsigned int mtty_get_available(struct mdev_type *mtype)
 {
-	unsigned int ports = mtype_get_type_group_id(mtype) + 1;
+	struct mtty_type *type = container_of(mtype, struct mtty_type, type);
 
-	return sprintf(buf, "%d\n", atomic_read(&mdev_avail_ports) / ports);
+	return atomic_read(&mdev_avail_ports) / type->nr_ports;
 }
 
-static MDEV_TYPE_ATTR_RO(available_instances);
-
-static ssize_t device_api_show(struct mdev_type *mtype,
-			       struct mdev_type_attribute *attr, char *buf)
-{
-	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
-}
-
-static MDEV_TYPE_ATTR_RO(device_api);
-
-static struct attribute *mdev_types_attrs[] = {
-	&mdev_type_attr_name.attr,
-	&mdev_type_attr_device_api.attr,
-	&mdev_type_attr_available_instances.attr,
-	NULL,
-};
-
-static struct attribute_group mdev_type_group1 = {
-	.name  = "1",
-	.attrs = mdev_types_attrs,
-};
-
-static struct attribute_group mdev_type_group2 = {
-	.name  = "2",
-	.attrs = mdev_types_attrs,
-};
-
-static struct attribute_group *mdev_type_groups[] = {
-	&mdev_type_group1,
-	&mdev_type_group2,
-	NULL,
-};
-
 static const struct vfio_device_ops mtty_dev_ops = {
 	.name = "vfio-mtty",
+	.init = mtty_init_dev,
+	.release = mtty_release_dev,
 	.read = mtty_read,
 	.write = mtty_write,
 	.ioctl = mtty_ioctl,
 };
 
 static struct mdev_driver mtty_driver = {
+	.device_api = VFIO_DEVICE_API_PCI_STRING,
 	.driver = {
 		.name = "mtty",
 		.owner = THIS_MODULE,
@@ -1301,7 +1282,7 @@ static struct mdev_driver mtty_driver = {
 	},
 	.probe = mtty_probe,
 	.remove	= mtty_remove,
-	.supported_type_groups = mdev_type_groups,
+	.get_available = mtty_get_available,
 };
 
 static void mtty_device_release(struct device *dev)
@@ -1352,7 +1333,9 @@ static int __init mtty_dev_init(void)
 	if (ret)
 		goto err_class;
 
-	ret = mdev_register_device(&mtty_dev.dev, &mtty_driver);
+	ret = mdev_register_parent(&mtty_dev.parent, &mtty_dev.dev,
+				   &mtty_driver, mtty_mdev_types,
+				   ARRAY_SIZE(mtty_mdev_types));
 	if (ret)
 		goto err_device;
 	return 0;
@@ -1372,7 +1355,7 @@ err_cdev:
 static void __exit mtty_dev_exit(void)
 {
 	mtty_dev.dev.bus = NULL;
-	mdev_unregister_device(&mtty_dev.dev);
+	mdev_unregister_parent(&mtty_dev.parent);
 
 	device_unregister(&mtty_dev.dev);
 	idr_destroy(&mtty_dev.vd_idr);