[PATCH V13 1/6] mdev: make mdev bus agnostic

From: Jason Wang
Date: Mon Nov 18 2019 - 06:00:56 EST

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Current mdev is tied to a VFIO specific "mdev" bus. This prevent mdev
from being used by other types of API/buses. So this patch tries to make
mdev bus agnostic through making a mdev core a thin module:

- decouple VFIO bus specific bits from mdev_core.c to mdev_vfio.c and
introduce mdev_vfio module
- require to specify the type of bus when registering mdev device and
mdev driver

With those modifications mdev become a generic module that could be
used by multiple types of virtual buses and devices.

Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
.../driver-api/vfio-mediated-device.rst | 68 ++++++------
MAINTAINERS | 1 +
drivers/gpu/drm/i915/gvt/kvmgt.c | 8 +-
drivers/s390/cio/vfio_ccw_ops.c | 6 +-
drivers/s390/crypto/vfio_ap_ops.c | 21 ++--
drivers/s390/crypto/vfio_ap_private.h | 2 +-
drivers/vfio/mdev/Kconfig | 17 ++-
drivers/vfio/mdev/Makefile | 4 +-
drivers/vfio/mdev/mdev_core.c | 104 +++++++++++++-----
drivers/vfio/mdev/mdev_driver.c | 29 ++---
drivers/vfio/mdev/mdev_private.h | 13 ++-
drivers/vfio/mdev/mdev_vfio.c | 48 ++++++++
drivers/vfio/mdev/vfio_mdev.c | 5 +-
drivers/vfio/vfio_iommu_type1.c | 6 +-
include/linux/mdev.h | 16 ++-
include/linux/mdev_vfio.h | 25 +++++
samples/vfio-mdev/mbochs.c | 8 +-
samples/vfio-mdev/mdpy.c | 8 +-
samples/vfio-mdev/mtty.c | 8 +-
19 files changed, 269 insertions(+), 128 deletions(-)
create mode 100644 drivers/vfio/mdev/mdev_vfio.c
create mode 100644 include/linux/mdev_vfio.h

diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
index 25eb7d5b834b..1887d27a565e 100644
--- a/Documentation/driver-api/vfio-mediated-device.rst
+++ b/Documentation/driver-api/vfio-mediated-device.rst
@@ -49,35 +49,37 @@ devices as examples, as these devices are the first devices to use this module::

+---------------+
| |
- | +-----------+ | mdev_register_driver() +--------------+
- | | | +<------------------------+ |
- | | mdev | | | |
- | | bus | +------------------------>+ vfio_mdev.ko |<-> VFIO user
- | | driver | | probe()/remove() | | APIs
- | | | | +--------------+
- | +-----------+ |
+ | MDEV CORE | mdev_register_driver() +--------------+
+ | MODULE +<------------------------+ |
+ | mdev.ko | | |
+ | +------------------------>+ vfio_mdev.ko |<-> VFIO user
+ | | probe()/remove() | | APIs
+ | | +--------------+
+ +---+-------+---+
+ | /|\
+ | |
+callbacks| | mdev_register_device()
+ | | mdev_register_bus()
+ \|/ |
+ +---+-------+---+
+ | | mdev_vfio_register_device() +--------------+
+ | +<-----------------------------+ |
+ | | | nvidia.ko |<-> physical
+ | +----------------------------->+ | device
+ | MDEV VFIO | callbacks +--------------+
+ | Physical |
+ | device | mdev_vfio_register_device() +--------------+
+ | interface |<-----------------------------+ |
+ | | | i915.ko |<-> physical
+ | mdev_vfio.ko +----------------------------->+ | device
+ | | callbacks +--------------+
+ | |
+ | | mdev_vfio_register_device() +--------------+
+ | +<-----------------------------+ |
+ | | | ccw_device.ko|<-> physical
+ | +----------------------------->+ | device
+ | | callbacks +--------------+
| |
- | MDEV CORE |
- | MODULE |
- | mdev.ko |
- | +-----------+ | mdev_register_device() +--------------+
- | | | +<------------------------+ |
- | | | | | nvidia.ko |<-> physical
- | | | +------------------------>+ | device
- | | | | callbacks +--------------+
- | | Physical | |
- | | device | | mdev_register_device() +--------------+
- | | interface | |<------------------------+ |
- | | | | | i915.ko |<-> physical
- | | | +------------------------>+ | device
- | | | | callbacks +--------------+
- | | | |
- | | | | mdev_register_device() +--------------+
- | | | +<------------------------+ |
- | | | | | ccw_device.ko|<-> physical
- | | | +------------------------>+ | device
- | | | | callbacks +--------------+
- | +-----------+ |
+---------------+

@@ -116,7 +118,8 @@ to register and unregister itself with the core driver:
* Register::

extern int mdev_register_driver(struct mdev_driver *drv,
- struct module *owner);
+ struct module *owner,
+ struct bus_type *bus);

* Unregister::

@@ -159,11 +162,12 @@ The callbacks in the mdev_parent_ops structure are as follows:
* write: write emulation callback
* mmap: mmap emulation callback

-A driver should use the mdev_parent_ops structure in the function call to
-register itself with the mdev core driver::
+A driver should use the mdev_parent_ops structure and bus type in the
+function call to register itself with the mdev core driver::

extern int mdev_register_device(struct device *dev,
- const struct mdev_parent_ops *ops);
+ const struct mdev_parent_ops *ops,
+ struct bus_type *bus);

However, the mdev_parent_ops structure is not required in the function call
that a driver should use to unregister itself with the mdev core driver::
diff --git a/MAINTAINERS b/MAINTAINERS
index 34ef0cf30ece..6d590afb62c3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17139,6 +17139,7 @@ S: Maintained
F: Documentation/driver-api/vfio-mediated-device.rst
F: drivers/vfio/mdev/
F: include/linux/mdev.h
+F: include/linux/mdev_vfio.h
F: samples/vfio-mdev/

VFIO PLATFORM DRIVER
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 04a5a0d90823..afdb3de5ce2f 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -41,7 +41,7 @@
#include <linux/uuid.h>
#include <linux/kvm_host.h>
#include <linux/vfio.h>
-#include <linux/mdev.h>
+#include <linux/mdev_vfio.h>
#include <linux/debugfs.h>

#include <linux/nospec.h>
@@ -1554,7 +1554,7 @@ static ssize_t
vgpu_id_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
- struct mdev_device *mdev = mdev_from_dev(dev);
+ struct mdev_device *mdev = vfio_mdev_from_dev(dev);

if (mdev) {
struct intel_vgpu *vgpu = (struct intel_vgpu *)
@@ -1606,12 +1606,12 @@ static int kvmgt_host_init(struct device *dev, void *gvt, const void *ops)
return -EFAULT;
intel_vgpu_ops.supported_type_groups = kvm_vgpu_type_groups;

- return mdev_register_device(dev, &intel_vgpu_ops);
+ return mdev_vfio_register_device(dev, &intel_vgpu_ops);
}

static void kvmgt_host_exit(struct device *dev)
{
- mdev_unregister_device(dev);
+ mdev_vfio_unregister_device(dev);
}

static int kvmgt_page_track_add(unsigned long handle, u64 gfn)
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index f0d71ab77c50..791b8b0eb027 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -11,7 +11,7 @@
*/

#include <linux/vfio.h>
-#include <linux/mdev.h>
+#include <linux/mdev_vfio.h>
#include <linux/nospec.h>
#include <linux/slab.h>

@@ -588,10 +588,10 @@ static const struct mdev_parent_ops vfio_ccw_mdev_ops = {

int vfio_ccw_mdev_reg(struct subchannel *sch)
{
- return mdev_register_device(&sch->dev, &vfio_ccw_mdev_ops);
+ return mdev_vfio_register_device(&sch->dev, &vfio_ccw_mdev_ops);
}

void vfio_ccw_mdev_unreg(struct subchannel *sch)
{
- mdev_unregister_device(&sch->dev);
+ mdev_vfio_unregister_device(&sch->dev);
}
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 5c0f53c6dde7..78048e670374 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -602,7 +602,7 @@ static ssize_t assign_adapter_store(struct device *dev,
{
int ret;
unsigned long apid;
- struct mdev_device *mdev = mdev_from_dev(dev);
+ struct mdev_device *mdev = vfio_mdev_from_dev(dev);
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);

/* If the guest is running, disallow assignment of adapter */
@@ -668,7 +668,7 @@ static ssize_t unassign_adapter_store(struct device *dev,
{
int ret;
unsigned long apid;
- struct mdev_device *mdev = mdev_from_dev(dev);
+ struct mdev_device *mdev = vfio_mdev_from_dev(dev);
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);

/* If the guest is running, disallow un-assignment of adapter */
@@ -748,7 +748,7 @@ static ssize_t assign_domain_store(struct device *dev,
{
int ret;
unsigned long apqi;
- struct mdev_device *mdev = mdev_from_dev(dev);
+ struct mdev_device *mdev = vfio_mdev_from_dev(dev);
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
unsigned long max_apqi = matrix_mdev->matrix.aqm_max;

@@ -810,7 +810,7 @@ static ssize_t unassign_domain_store(struct device *dev,
{
int ret;
unsigned long apqi;
- struct mdev_device *mdev = mdev_from_dev(dev);
+ struct mdev_device *mdev = vfio_mdev_from_dev(dev);
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);

/* If the guest is running, disallow un-assignment of domain */
@@ -854,7 +854,7 @@ static ssize_t assign_control_domain_store(struct device *dev,
{
int ret;
unsigned long id;
- struct mdev_device *mdev = mdev_from_dev(dev);
+ struct mdev_device *mdev = vfio_mdev_from_dev(dev);
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);

/* If the guest is running, disallow assignment of control domain */
@@ -903,7 +903,7 @@ static ssize_t unassign_control_domain_store(struct device *dev,
{
int ret;
unsigned long domid;
- struct mdev_device *mdev = mdev_from_dev(dev);
+ struct mdev_device *mdev = vfio_mdev_from_dev(dev);
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
unsigned long max_domid = matrix_mdev->matrix.adm_max;

@@ -933,7 +933,7 @@ static ssize_t control_domains_show(struct device *dev,
int nchars = 0;
int n;
char *bufpos = buf;
- struct mdev_device *mdev = mdev_from_dev(dev);
+ struct mdev_device *mdev = vfio_mdev_from_dev(dev);
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
unsigned long max_domid = matrix_mdev->matrix.adm_max;

@@ -952,7 +952,7 @@ static DEVICE_ATTR_RO(control_domains);
static ssize_t matrix_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
- struct mdev_device *mdev = mdev_from_dev(dev);
+ struct mdev_device *mdev = vfio_mdev_from_dev(dev);
struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
char *bufpos = buf;
unsigned long apid;
@@ -1295,10 +1295,11 @@ int vfio_ap_mdev_register(void)
{
atomic_set(&matrix_dev->available_instances, MAX_ZDEV_ENTRIES_EXT);

- return mdev_register_device(&matrix_dev->device, &vfio_ap_matrix_ops);
+ return mdev_vfio_register_device(&matrix_dev->device,
+ &vfio_ap_matrix_ops);
}

void vfio_ap_mdev_unregister(void)
{
- mdev_unregister_device(&matrix_dev->device);
+ mdev_vfio_unregister_device(&matrix_dev->device);
}
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index f46dde56b464..4e37e0e3433a 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -14,7 +14,7 @@

#include <linux/types.h>
#include <linux/device.h>
-#include <linux/mdev.h>
+#include <linux/mdev_vfio.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/kvm_host.h>
diff --git a/drivers/vfio/mdev/Kconfig b/drivers/vfio/mdev/Kconfig
index 5da27f2100f9..2e07ca915a96 100644
--- a/drivers/vfio/mdev/Kconfig
+++ b/drivers/vfio/mdev/Kconfig
@@ -1,15 +1,24 @@
-# SPDX-License-Identifier: GPL-2.0-only

-config VFIO_MDEV
+config MDEV
tristate "Mediated device driver framework"
- depends on VFIO
default n
help
Provides a framework to virtualize devices.
- See Documentation/driver-api/vfio-mediated-device.rst for more details.

If you don't know what do here, say N.

+config VFIO_MDEV
+ tristate "VFIO Mediated device driver"
+ depends on VFIO && MDEV
+ default n
+ help
+ Proivdes a mediated BUS for userspace driver through VFIO
+ framework. See Documentation/vfio-mediated-device.txt for
+ more details.
+
+ If you don't know what do here, say N.
+
+
config VFIO_MDEV_DEVICE
tristate "VFIO driver for Mediated devices"
depends on VFIO && VFIO_MDEV
diff --git a/drivers/vfio/mdev/Makefile b/drivers/vfio/mdev/Makefile
index 101516fdf375..e9675501271a 100644
--- a/drivers/vfio/mdev/Makefile
+++ b/drivers/vfio/mdev/Makefile
@@ -1,6 +1,6 @@
-# SPDX-License-Identifier: GPL-2.0-only

mdev-y := mdev_core.o mdev_sysfs.o mdev_driver.o

-obj-$(CONFIG_VFIO_MDEV) += mdev.o
+obj-$(CONFIG_MDEV) += mdev.o
+obj-$(CONFIG_VFIO_MDEV) += mdev_vfio.o
obj-$(CONFIG_VFIO_MDEV_DEVICE) += vfio_mdev.o
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index b558d4cfd082..e1272a40c521 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -22,11 +22,13 @@

static LIST_HEAD(parent_list);
static DEFINE_MUTEX(parent_list_lock);
-static struct class_compat *mdev_bus_compat_class;

static LIST_HEAD(mdev_list);
static DEFINE_MUTEX(mdev_list_lock);

+static LIST_HEAD(class_compat_list);
+static DEFINE_MUTEX(compat_list_lock);
+
struct device *mdev_parent_dev(struct mdev_device *mdev)
{
return mdev->parent->dev;
@@ -51,9 +53,9 @@ struct device *mdev_dev(struct mdev_device *mdev)
}
EXPORT_SYMBOL(mdev_dev);

-struct mdev_device *mdev_from_dev(struct device *dev)
+struct mdev_device *mdev_from_dev(struct device *dev, struct bus_type *bus)
{
- return dev_is_mdev(dev) ? to_mdev_device(dev) : NULL;
+ return dev_is_mdev(dev, bus) ? to_mdev_device(dev) : NULL;
}
EXPORT_SYMBOL(mdev_from_dev);

@@ -122,7 +124,9 @@ static void mdev_device_remove_common(struct mdev_device *mdev)

static int mdev_device_remove_cb(struct device *dev, void *data)
{
- if (dev_is_mdev(dev)) {
+ struct bus_type *bus = data;
+
+ if (dev_is_mdev(dev, bus)) {
struct mdev_device *mdev;

mdev = to_mdev_device(dev);
@@ -131,6 +135,41 @@ static int mdev_device_remove_cb(struct device *dev, void *data)
return 0;
}

+static struct mdev_class_compat *get_class_compat(struct bus_type *bus)
+{
+ struct mdev_class_compat *mdev_class_compat;
+
+ list_for_each_entry(mdev_class_compat, &class_compat_list, next) {
+ if (mdev_class_compat->bus == bus)
+ return mdev_class_compat;
+ }
+
+ return NULL;
+}
+
+static struct class_compat *mdev_alloc_class_compat(struct bus_type *bus)
+{
+ struct mdev_class_compat *mdev_class_compat = get_class_compat(bus);
+ char class_name[64];
+
+ if (mdev_class_compat)
+ return mdev_class_compat->class_compat;
+
+ mdev_class_compat = kmalloc(sizeof(*mdev_class_compat), GFP_KERNEL);
+ if (!mdev_class_compat)
+ return NULL;
+ snprintf(class_name, 64, "%s_bus", bus->name);
+ mdev_class_compat->class_compat = class_compat_register(class_name);
+ if (!mdev_class_compat->class_compat) {
+ kfree(mdev_class_compat);
+ return NULL;
+ }
+ mdev_class_compat->bus = bus;
+ list_add(&mdev_class_compat->next, &class_compat_list);
+
+ return mdev_class_compat->class_compat;
+}
+
/*
* mdev_register_device : Register a device
* @dev: device structure representing parent device.
@@ -139,12 +178,14 @@ static int mdev_device_remove_cb(struct device *dev, void *data)
* Add device to list of registered parent devices.
* Returns a negative value on error, otherwise 0.
*/
-int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
+int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops,
+ struct bus_type *bus)
{
int ret;
struct mdev_parent *parent;
char *env_string = "MDEV_STATE=registered";
char *envp[] = { env_string, NULL };
+ struct class_compat *class_compat;

/* check for mandatory ops */
if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups)
@@ -175,20 +216,21 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)

parent->dev = dev;
parent->ops = ops;
+ parent->bus = bus;

- if (!mdev_bus_compat_class) {
- mdev_bus_compat_class = class_compat_register("mdev_bus");
- if (!mdev_bus_compat_class) {
- ret = -ENOMEM;
- goto add_dev_err;
- }
+ mutex_lock(&compat_list_lock);
+ class_compat = mdev_alloc_class_compat(bus);
+ mutex_unlock(&compat_list_lock);
+ if (!class_compat) {
+ ret = -ENOMEM;
+ goto add_dev_err;
}

ret = parent_create_sysfs_files(parent);
if (ret)
goto add_dev_err;

- ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
+ ret = class_compat_create_link(class_compat, dev, NULL);
if (ret)
dev_warn(dev, "Failed to create compatibility class link\n");

@@ -223,6 +265,7 @@ void mdev_unregister_device(struct device *dev)
struct mdev_parent *parent;
char *env_string = "MDEV_STATE=unregistered";
char *envp[] = { env_string, NULL };
+ struct mdev_class_compat *mdev_class_compat;

mutex_lock(&parent_list_lock);
parent = __find_parent_device(dev);
@@ -238,9 +281,13 @@ void mdev_unregister_device(struct device *dev)

down_write(&parent->unreg_sem);

- class_compat_remove_link(mdev_bus_compat_class, dev, NULL);
+ mutex_lock(&compat_list_lock);
+ mdev_class_compat = get_class_compat(parent->bus);
+ WARN_ON(!mdev_class_compat);
+ class_compat_remove_link(mdev_class_compat->class_compat, dev, NULL);
+ mutex_unlock(&compat_list_lock);

- device_for_each_child(dev, NULL, mdev_device_remove_cb);
+ device_for_each_child(dev, parent->bus, mdev_device_remove_cb);

parent_remove_sysfs_files(parent);
up_write(&parent->unreg_sem);
@@ -314,7 +361,7 @@ int mdev_device_create(struct kobject *kobj,

device_initialize(&mdev->dev);
mdev->dev.parent = dev;
- mdev->dev.bus = &mdev_bus_type;
+ mdev->dev.bus = parent->bus;
mdev->dev.release = mdev_device_release;
dev_set_name(&mdev->dev, "%pUl", uuid);
mdev->dev.groups = parent->ops->mdev_attr_groups;
@@ -404,24 +451,29 @@ struct device *mdev_get_iommu_device(struct device *dev)
}
EXPORT_SYMBOL(mdev_get_iommu_device);

-static int __init mdev_init(void)
+int mdev_register_bus(struct bus_type *bus)
{
- return mdev_bus_register();
+ return bus_register(bus);
}
+EXPORT_SYMBOL(mdev_register_bus);

-static void __exit mdev_exit(void)
+void mdev_unregister_bus(struct bus_type *bus)
{
- if (mdev_bus_compat_class)
- class_compat_unregister(mdev_bus_compat_class);
-
- mdev_bus_unregister();
+ struct mdev_class_compat *mdev_class_compat;
+
+ mutex_lock(&compat_list_lock);
+ mdev_class_compat = get_class_compat(bus);
+ if (mdev_class_compat) {
+ list_del(&mdev_class_compat->next);
+ class_compat_unregister(mdev_class_compat->class_compat);
+ kfree(mdev_class_compat);
+ }
+ bus_unregister(bus);
+ mutex_unlock(&compat_list_lock);
}
-
-module_init(mdev_init)
-module_exit(mdev_exit)
+EXPORT_SYMBOL(mdev_unregister_bus);

MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
-MODULE_SOFTDEP("post: vfio_mdev");
diff --git a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
index 0d3223aee20b..c3a2ac023712 100644
--- a/drivers/vfio/mdev/mdev_driver.c
+++ b/drivers/vfio/mdev/mdev_driver.c
@@ -10,6 +10,7 @@
#include <linux/device.h>
#include <linux/iommu.h>
#include <linux/mdev.h>
+#include <linux/mdev_vfio.h>

#include "mdev_private.h"

@@ -37,7 +38,7 @@ static void mdev_detach_iommu(struct mdev_device *mdev)
dev_info(&mdev->dev, "MDEV: detaching iommu\n");
}

-static int mdev_probe(struct device *dev)
+int mdev_probe(struct device *dev)
{
struct mdev_driver *drv = to_mdev_driver(dev->driver);
struct mdev_device *mdev = to_mdev_device(dev);
@@ -55,8 +56,9 @@ static int mdev_probe(struct device *dev)

return ret;
}
+EXPORT_SYMBOL(mdev_probe);

-static int mdev_remove(struct device *dev)
+int mdev_remove(struct device *dev)
{
struct mdev_driver *drv = to_mdev_driver(dev->driver);
struct mdev_device *mdev = to_mdev_device(dev);
@@ -68,26 +70,22 @@ static int mdev_remove(struct device *dev)

return 0;
}
-
-struct bus_type mdev_bus_type = {
- .name = "mdev",
- .probe = mdev_probe,
- .remove = mdev_remove,
-};
-EXPORT_SYMBOL_GPL(mdev_bus_type);
+EXPORT_SYMBOL(mdev_remove);

/**
* mdev_register_driver - register a new MDEV driver
* @drv: the driver to register
* @owner: module owner of driver to be registered
+ * @bus: but that the driver wants to attach
*
* Returns a negative value on error, otherwise 0.
**/
-int mdev_register_driver(struct mdev_driver *drv, struct module *owner)
+int mdev_register_driver(struct mdev_driver *drv, struct module *owner,
+ struct bus_type *bus)
{
/* initialize common driver fields */
drv->driver.name = drv->name;
- drv->driver.bus = &mdev_bus_type;
+ drv->driver.bus = bus;
drv->driver.owner = owner;

/* register with core */
@@ -105,12 +103,3 @@ void mdev_unregister_driver(struct mdev_driver *drv)
}
EXPORT_SYMBOL(mdev_unregister_driver);

-int mdev_bus_register(void)
-{
- return bus_register(&mdev_bus_type);
-}
-
-void mdev_bus_unregister(void)
-{
- bus_unregister(&mdev_bus_type);
-}
diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
index 7d922950caaf..298d7a0f493a 100644
--- a/drivers/vfio/mdev/mdev_private.h
+++ b/drivers/vfio/mdev/mdev_private.h
@@ -10,12 +10,10 @@
#ifndef MDEV_PRIVATE_H
#define MDEV_PRIVATE_H

-int mdev_bus_register(void);
-void mdev_bus_unregister(void);
-
struct mdev_parent {
struct device *dev;
const struct mdev_parent_ops *ops;
+ struct bus_type *bus;
struct kref ref;
struct list_head next;
struct kset *mdev_types_kset;
@@ -35,8 +33,15 @@ struct mdev_device {
bool active;
};

+struct mdev_class_compat {
+ struct class_compat *class_compat;
+ struct bus_type *bus;
+ struct list_head next;
+};
+
+
#define to_mdev_device(dev) container_of(dev, struct mdev_device, dev)
-#define dev_is_mdev(d) ((d)->bus == &mdev_bus_type)
+#define dev_is_mdev(d, bus) ((d)->bus == bus)

struct mdev_type {
struct kobject kobj;
diff --git a/drivers/vfio/mdev/mdev_vfio.c b/drivers/vfio/mdev/mdev_vfio.c
new file mode 100644
index 000000000000..f9d1191b9982
--- /dev/null
+++ b/drivers/vfio/mdev/mdev_vfio.c
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/module.h>
+#include <linux/uuid.h>
+#include <linux/device.h>
+#include <linux/mdev_vfio.h>
+
+#define DRIVER_VERSION "0.1"
+#define DRIVER_AUTHOR "Jason Wang"
+#define DRIVER_DESC "Mediated VFIO bus"
+
+struct bus_type mdev_vfio_bus_type = {
+ .name = "mdev",
+ .probe = mdev_probe,
+ .remove = mdev_remove,
+};
+EXPORT_SYMBOL(mdev_vfio_bus_type);
+
+static int __init mdev_init(void)
+{
+ return mdev_register_bus(&mdev_vfio_bus_type);
+}
+
+static void __exit mdev_exit(void)
+{
+ mdev_unregister_bus(&mdev_vfio_bus_type);
+}
+
+int mdev_vfio_register_device(struct device *dev,
+ const struct mdev_parent_ops *ops)
+{
+ return mdev_register_device(dev, ops, &mdev_vfio_bus_type);
+}
+EXPORT_SYMBOL(mdev_vfio_register_device);
+
+void mdev_vfio_unregister_device(struct device *dev)
+{
+ return mdev_unregister_device(dev);
+}
+EXPORT_SYMBOL(mdev_vfio_unregister_device);
+
+module_init(mdev_init)
+module_exit(mdev_exit)
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_SOFTDEP("post: vfio_mdev");
diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
index 30964a4e0a28..16e9ebe30d4a 100644
--- a/drivers/vfio/mdev/vfio_mdev.c
+++ b/drivers/vfio/mdev/vfio_mdev.c
@@ -13,7 +13,7 @@
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/vfio.h>
-#include <linux/mdev.h>
+#include <linux/mdev_vfio.h>

#include "mdev_private.h"

@@ -128,7 +128,8 @@ static struct mdev_driver vfio_mdev_driver = {

static int __init vfio_mdev_init(void)
{
- return mdev_register_driver(&vfio_mdev_driver, THIS_MODULE);
+ return mdev_register_driver(&vfio_mdev_driver, THIS_MODULE,
+ &mdev_vfio_bus_type);
}

static void __exit vfio_mdev_exit(void)
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index d864277ea16f..f35523f822eb 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -34,7 +34,7 @@
#include <linux/uaccess.h>
#include <linux/vfio.h>
#include <linux/workqueue.h>
-#include <linux/mdev.h>
+#include <linux/mdev_vfio.h>
#include <linux/notifier.h>
#include <linux/dma-iommu.h>
#include <linux/irqdomain.h>
@@ -1405,10 +1405,10 @@ static bool vfio_bus_is_mdev(struct bus_type *bus)
struct bus_type *mdev_bus;
bool ret = false;

- mdev_bus = symbol_get(mdev_bus_type);
+ mdev_bus = symbol_get(mdev_vfio_bus_type);
if (mdev_bus) {
ret = (bus == mdev_bus);
- symbol_put(mdev_bus_type);
+ symbol_put(mdev_vfio_bus_type);
}

return ret;
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 0ce30ca78db0..ee2410246b3c 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -133,16 +133,22 @@ void *mdev_get_drvdata(struct mdev_device *mdev);
void mdev_set_drvdata(struct mdev_device *mdev, void *data);
const guid_t *mdev_uuid(struct mdev_device *mdev);

-extern struct bus_type mdev_bus_type;
-
-int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops);
+int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops,
+ struct bus_type *bus);
void mdev_unregister_device(struct device *dev);

-int mdev_register_driver(struct mdev_driver *drv, struct module *owner);
+int mdev_register_driver(struct mdev_driver *drv, struct module *owner,
+ struct bus_type *bus);
void mdev_unregister_driver(struct mdev_driver *drv);

struct device *mdev_parent_dev(struct mdev_device *mdev);
struct device *mdev_dev(struct mdev_device *mdev);
-struct mdev_device *mdev_from_dev(struct device *dev);
+struct mdev_device *mdev_from_dev(struct device *dev, struct bus_type *bus);
+
+int mdev_probe(struct device *dev);
+int mdev_remove(struct device *dev);
+
+int mdev_register_bus(struct bus_type *bus);
+void mdev_unregister_bus(struct bus_type *bus);

#endif /* MDEV_H */
diff --git a/include/linux/mdev_vfio.h b/include/linux/mdev_vfio.h
new file mode 100644
index 000000000000..446a7537e3fb
--- /dev/null
+++ b/include/linux/mdev_vfio.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * VFIO Mediated device definition
+ *
+ * Copyright (c) 2019, Red Hat. All rights reserved.
+ * Author: Jason Wang <jasowang@xxxxxxxxxx>
+ */
+
+#ifndef MDEV_VFIO_H
+#define MDEV_VFIO_H
+
+#include <linux/mdev.h>
+
+extern struct bus_type mdev_vfio_bus_type;
+
+int mdev_vfio_register_device(struct device *dev,
+ const struct mdev_parent_ops *ops);
+void mdev_vfio_unregister_device(struct device *dev);
+
+static inline struct mdev_device *vfio_mdev_from_dev(struct device *dev)
+{
+ return mdev_from_dev(dev, &mdev_vfio_bus_type);
+}
+
+#endif
diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index ac5c8c17b1ff..f041d58324b1 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -29,7 +29,7 @@
#include <linux/vfio.h>
#include <linux/iommu.h>
#include <linux/sysfs.h>
-#include <linux/mdev.h>
+#include <linux/mdev_vfio.h>
#include <linux/pci.h>
#include <linux/dma-buf.h>
#include <linux/highmem.h>
@@ -1332,7 +1332,7 @@ static ssize_t
memory_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
- struct mdev_device *mdev = mdev_from_dev(dev);
+ struct mdev_device *mdev = vfio_mdev_from_dev(dev);
struct mdev_state *mdev_state = mdev_get_drvdata(mdev);

return sprintf(buf, "%d MB\n", mdev_state->type->mbytes);
@@ -1468,7 +1468,7 @@ static int __init mbochs_dev_init(void)
if (ret)
goto failed2;

- ret = mdev_register_device(&mbochs_dev, &mdev_fops);
+ ret = mdev_vfio_register_device(&mbochs_dev, &mdev_fops);
if (ret)
goto failed3;

@@ -1487,7 +1487,7 @@ static int __init mbochs_dev_init(void)
static void __exit mbochs_dev_exit(void)
{
mbochs_dev.bus = NULL;
- mdev_unregister_device(&mbochs_dev);
+ mdev_vfio_unregister_device(&mbochs_dev);

device_unregister(&mbochs_dev);
cdev_del(&mbochs_cdev);
diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
index cc86bf6566e4..9c32fe3795ad 100644
--- a/samples/vfio-mdev/mdpy.c
+++ b/samples/vfio-mdev/mdpy.c
@@ -25,7 +25,7 @@
#include <linux/vfio.h>
#include <linux/iommu.h>
#include <linux/sysfs.h>
-#include <linux/mdev.h>
+#include <linux/mdev_vfio.h>
#include <linux/pci.h>
#include <drm/drm_fourcc.h>
#include "mdpy-defs.h"
@@ -639,7 +639,7 @@ static ssize_t
resolution_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
- struct mdev_device *mdev = mdev_from_dev(dev);
+ struct mdev_device *mdev = vfio_mdev_from_dev(dev);
struct mdev_state *mdev_state = mdev_get_drvdata(mdev);

return sprintf(buf, "%dx%d\n",
@@ -775,7 +775,7 @@ static int __init mdpy_dev_init(void)
if (ret)
goto failed2;

- ret = mdev_register_device(&mdpy_dev, &mdev_fops);
+ ret = mdev_vfio_register_device(&mdpy_dev, &mdev_fops);
if (ret)
goto failed3;

@@ -794,7 +794,7 @@ static int __init mdpy_dev_init(void)
static void __exit mdpy_dev_exit(void)
{
mdpy_dev.bus = NULL;
- mdev_unregister_device(&mdpy_dev);
+ mdev_vfio_unregister_device(&mdpy_dev);

device_unregister(&mdpy_dev);
cdev_del(&mdpy_cdev);
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index ce84a300a4da..6e4e6339e0f1 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -26,7 +26,7 @@
#include <linux/sysfs.h>
#include <linux/ctype.h>
#include <linux/file.h>
-#include <linux/mdev.h>
+#include <linux/mdev_vfio.h>
#include <linux/pci.h>
#include <linux/serial.h>
#include <uapi/linux/serial_reg.h>
@@ -1285,7 +1285,7 @@ static ssize_t
sample_mdev_dev_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
- if (mdev_from_dev(dev))
+ if (vfio_mdev_from_dev(dev))
return sprintf(buf, "This is MDEV %s\n", dev_name(dev));

return sprintf(buf, "\n");
@@ -1445,7 +1445,7 @@ static int __init mtty_dev_init(void)
if (ret)
goto failed2;

- ret = mdev_register_device(&mtty_dev.dev, &mdev_fops);
+ ret = mdev_vfio_register_device(&mtty_dev.dev, &mdev_fops);
if (ret)
goto failed3;

@@ -1471,7 +1471,7 @@ static int __init mtty_dev_init(void)
static void __exit mtty_dev_exit(void)
{
mtty_dev.dev.bus = NULL;
- mdev_unregister_device(&mtty_dev.dev);
+ mdev_vfio_unregister_device(&mtty_dev.dev);

device_unregister(&mtty_dev.dev);
idr_destroy(&mtty_dev.vd_idr);
--
2.19.1

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