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[Qemu-devel] [RFC PATCH v4 1/3] Mediated device Core driver


From: Kirti Wankhede
Subject: [Qemu-devel] [RFC PATCH v4 1/3] Mediated device Core driver
Date: Wed, 25 May 2016 01:28:15 +0530

Design for Mediated Device Driver:
Main purpose of this driver is to provide a common interface for mediated
device management that can be used by differnt drivers of different
devices.

This module provides a generic interface to create the device, add it to
mediated bus, add device to IOMMU group and then add it to vfio group.

Below is the high Level block diagram, with Nvidia, Intel and IBM devices
as example, since these are the devices which are going to actively use
this module as of now.

 +---------------+
 |               |
 | +-----------+ |  mdev_register_driver() +--------------+
 | |           | +<------------------------+ __init()     |
 | |           | |                         |              |
 | |  mdev     | +------------------------>+              |<-> VFIO user
 | |  bus      | |     probe()/remove()    | vfio_mpci.ko |    APIs
 | |  driver   | |                         |              |
 | |           | |                         +--------------+
 | |           | |  mdev_register_driver() +--------------+
 | |           | +<------------------------+ __init()     |
 | |           | |                         |              |
 | |           | +------------------------>+              |<-> VFIO user
 | +-----------+ |     probe()/remove()    | vfio_mccw.ko |    APIs
 |               |                         |              |
 |  MDEV CORE    |                         +--------------+
 |   MODULE      |
 |   mdev.ko     |
 | +-----------+ |  mdev_register_device() +--------------+
 | |           | +<------------------------+              |
 | |           | |                         |  nvidia.ko   |<-> physical
 | |           | +------------------------>+              |    device
 | |           | |        callback         +--------------+
 | | Physical  | |
 | |  device   | |  mdev_register_device() +--------------+
 | | interface | |<------------------------+              |
 | |           | |                         |  i915.ko     |<-> physical
 | |           | +------------------------>+              |    device
 | |           | |        callback         +--------------+
 | |           | |
 | |           | |  mdev_register_device() +--------------+
 | |           | +<------------------------+              |
 | |           | |                         | ccw_device.ko|<-> physical
 | |           | +------------------------>+              |    device
 | |           | |        callback         +--------------+
 | +-----------+ |
 +---------------+

Core driver provides two types of registration interfaces:
1. Registration interface for mediated bus driver:

/**
  * struct mdev_driver - Mediated device's driver
  * @name: driver name
  * @probe: called when new device created
  * @remove:called when device removed
  * @match: called when new device or driver is added for this bus.
            Return 1 if given device can be handled by given driver and
            zero otherwise.
  * @driver:device driver structure
  *
  **/
struct mdev_driver {
         const char *name;
         int  (*probe)  (struct device *dev);
         void (*remove) (struct device *dev);
         int  (*match)(struct device *dev);
         struct device_driver    driver;
};

int  mdev_register_driver(struct mdev_driver *drv, struct module *owner);
void mdev_unregister_driver(struct mdev_driver *drv);

Mediated device's driver for mdev should use this interface to register
with Core driver. With this, mediated devices driver for such devices is
responsible to add mediated device to VFIO group.

2. Physical device driver interface
This interface provides vendor driver the set APIs to manage physical
device related work in their own driver. APIs are :
- supported_config: provide supported configuration list by the vendor
                    driver
- create: to allocate basic resources in vendor driver for a mediated
          device.
- destroy: to free resources in vendor driver when mediated device is
           destroyed.
- start: to initiate mediated device initialization process from vendor
         driver when VM boots and before QEMU starts.
- shutdown: to teardown mediated device resources during VM teardown.
- read : read emulation callback.
- write: write emulation callback.
- set_irqs: send interrupt configuration information that QEMU sets.
- get_region_info: to provide region size and its flags for the mediated
                   device.
- validate_map_request: to validate remap pfn request.

This registration interface should be used by vendor drivers to register
each physical device to mdev core driver.

Signed-off-by: Kirti Wankhede <address@hidden>
Signed-off-by: Neo Jia <address@hidden>
Change-Id: I88f4482f7608f40550a152c5f882b64271287c62
---
 drivers/vfio/Kconfig             |   1 +
 drivers/vfio/Makefile            |   1 +
 drivers/vfio/mdev/Kconfig        |  11 +
 drivers/vfio/mdev/Makefile       |   5 +
 drivers/vfio/mdev/mdev-core.c    | 462 +++++++++++++++++++++++++++++++++++++++
 drivers/vfio/mdev/mdev-driver.c  | 139 ++++++++++++
 drivers/vfio/mdev/mdev-sysfs.c   | 312 ++++++++++++++++++++++++++
 drivers/vfio/mdev/mdev_private.h |  33 +++
 include/linux/mdev.h             | 224 +++++++++++++++++++
 9 files changed, 1188 insertions(+)
 create mode 100644 drivers/vfio/mdev/Kconfig
 create mode 100644 drivers/vfio/mdev/Makefile
 create mode 100644 drivers/vfio/mdev/mdev-core.c
 create mode 100644 drivers/vfio/mdev/mdev-driver.c
 create mode 100644 drivers/vfio/mdev/mdev-sysfs.c
 create mode 100644 drivers/vfio/mdev/mdev_private.h
 create mode 100644 include/linux/mdev.h

diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
index da6e2ce77495..23eced02aaf6 100644
--- a/drivers/vfio/Kconfig
+++ b/drivers/vfio/Kconfig
@@ -48,4 +48,5 @@ menuconfig VFIO_NOIOMMU
 
 source "drivers/vfio/pci/Kconfig"
 source "drivers/vfio/platform/Kconfig"
+source "drivers/vfio/mdev/Kconfig"
 source "virt/lib/Kconfig"
diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
index 7b8a31f63fea..7c70753e54ab 100644
--- a/drivers/vfio/Makefile
+++ b/drivers/vfio/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
 obj-$(CONFIG_VFIO_SPAPR_EEH) += vfio_spapr_eeh.o
 obj-$(CONFIG_VFIO_PCI) += pci/
 obj-$(CONFIG_VFIO_PLATFORM) += platform/
+obj-$(CONFIG_MDEV) += mdev/
diff --git a/drivers/vfio/mdev/Kconfig b/drivers/vfio/mdev/Kconfig
new file mode 100644
index 000000000000..951e2bb06a3f
--- /dev/null
+++ b/drivers/vfio/mdev/Kconfig
@@ -0,0 +1,11 @@
+
+config MDEV
+    tristate "Mediated device driver framework"
+    depends on VFIO
+    default n
+    help
+        MDEV provides a framework to virtualize device without SR-IOV cap
+        See Documentation/mdev.txt for more details.
+
+        If you don't know what do here, say N.
+
diff --git a/drivers/vfio/mdev/Makefile b/drivers/vfio/mdev/Makefile
new file mode 100644
index 000000000000..4adb069febce
--- /dev/null
+++ b/drivers/vfio/mdev/Makefile
@@ -0,0 +1,5 @@
+
+mdev-y := mdev-core.o mdev-sysfs.o mdev-driver.o
+
+obj-$(CONFIG_MDEV) += mdev.o
+
diff --git a/drivers/vfio/mdev/mdev-core.c b/drivers/vfio/mdev/mdev-core.c
new file mode 100644
index 000000000000..af070d73735f
--- /dev/null
+++ b/drivers/vfio/mdev/mdev-core.c
@@ -0,0 +1,462 @@
+/*
+ * Mediated device Core Driver
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <address@hidden>
+ *            Kirti Wankhede <address@hidden>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/cdev.h>
+#include <linux/sched.h>
+#include <linux/uuid.h>
+#include <linux/vfio.h>
+#include <linux/iommu.h>
+#include <linux/sysfs.h>
+#include <linux/mdev.h>
+
+#include "mdev_private.h"
+
+#define DRIVER_VERSION         "0.1"
+#define DRIVER_AUTHOR          "NVIDIA Corporation"
+#define DRIVER_DESC            "Mediated device Core Driver"
+
+#define MDEV_CLASS_NAME                "mdev"
+
+/*
+ * Global Structures
+ */
+
+static struct devices_list {
+       struct list_head    dev_list;
+       struct mutex        list_lock;
+} mdevices, phy_devices;
+
+/*
+ * Functions
+ */
+
+static int mdev_add_attribute_group(struct device *dev,
+                                   const struct attribute_group **groups)
+{
+       return sysfs_create_groups(&dev->kobj, groups);
+}
+
+static void mdev_remove_attribute_group(struct device *dev,
+                                       const struct attribute_group **groups)
+{
+       sysfs_remove_groups(&dev->kobj, groups);
+}
+
+static struct mdev_device *find_mdev_device(uuid_le uuid, int instance)
+{
+       struct mdev_device *vdev = NULL, *v;
+
+       mutex_lock(&mdevices.list_lock);
+       list_for_each_entry(v, &mdevices.dev_list, next) {
+               if ((uuid_le_cmp(v->uuid, uuid) == 0) &&
+                   (v->instance == instance)) {
+                       vdev = v;
+                       break;
+               }
+       }
+       mutex_unlock(&mdevices.list_lock);
+       return vdev;
+}
+
+static struct mdev_device *find_next_mdev_device(struct phy_device *phy_dev)
+{
+       struct mdev_device *mdev = NULL, *p;
+
+       mutex_lock(&mdevices.list_lock);
+       list_for_each_entry(p, &mdevices.dev_list, next) {
+               if (p->phy_dev == phy_dev) {
+                       mdev = p;
+                       break;
+               }
+       }
+       mutex_unlock(&mdevices.list_lock);
+       return mdev;
+}
+
+static struct phy_device *find_physical_device(struct device *dev)
+{
+       struct phy_device *pdev = NULL, *p;
+
+       mutex_lock(&phy_devices.list_lock);
+       list_for_each_entry(p, &phy_devices.dev_list, next) {
+               if (p->dev == dev) {
+                       pdev = p;
+                       break;
+               }
+       }
+       mutex_unlock(&phy_devices.list_lock);
+       return pdev;
+}
+
+static void mdev_destroy_device(struct mdev_device *mdevice)
+{
+       struct phy_device *phy_dev = mdevice->phy_dev;
+
+       if (phy_dev) {
+               mutex_lock(&phy_devices.list_lock);
+
+               /*
+               * If vendor driver doesn't return success that means vendor
+               * driver doesn't support hot-unplug
+               */
+               if (phy_dev->ops->destroy) {
+                       if (phy_dev->ops->destroy(phy_dev->dev, mdevice->uuid,
+                                                 mdevice->instance)) {
+                               mutex_unlock(&phy_devices.list_lock);
+                               return;
+                       }
+               }
+
+               mdev_remove_attribute_group(&mdevice->dev,
+                                           phy_dev->ops->mdev_attr_groups);
+               mdevice->phy_dev = NULL;
+               mutex_unlock(&phy_devices.list_lock);
+       }
+
+       mdev_put_device(mdevice);
+       device_unregister(&mdevice->dev);
+}
+
+/*
+ * Find mediated device from given iommu_group and increment refcount of
+ * mediated device. Caller should call mdev_put_device() when the use of
+ * mdev_device is done.
+ */
+struct mdev_device *mdev_get_device_by_group(struct iommu_group *group)
+{
+       struct mdev_device *mdev = NULL, *p;
+
+       mutex_lock(&mdevices.list_lock);
+       list_for_each_entry(p, &mdevices.dev_list, next) {
+               if (!p->group)
+                       continue;
+
+               if (iommu_group_id(p->group) == iommu_group_id(group)) {
+                       mdev = mdev_get_device(p);
+                       break;
+               }
+       }
+       mutex_unlock(&mdevices.list_lock);
+       return mdev;
+}
+EXPORT_SYMBOL_GPL(mdev_get_device_by_group);
+
+/*
+ * mdev_register_device : Register a device
+ * @dev: device structure representing physical device.
+ * @phy_device_ops: Physical device operation structure to be registered.
+ *
+ * Add device to list of registered physical devices.
+ * Returns a negative value on error, otherwise 0.
+ */
+int mdev_register_device(struct device *dev, const struct phy_device_ops *ops)
+{
+       int ret = 0;
+       struct phy_device *phy_dev, *pdev;
+
+       if (!dev || !ops)
+               return -EINVAL;
+
+       /* Check for duplicate */
+       pdev = find_physical_device(dev);
+       if (pdev)
+               return -EEXIST;
+
+       phy_dev = kzalloc(sizeof(*phy_dev), GFP_KERNEL);
+       if (!phy_dev)
+               return -ENOMEM;
+
+       phy_dev->dev = dev;
+       phy_dev->ops = ops;
+
+       mutex_lock(&phy_devices.list_lock);
+       ret = mdev_create_sysfs_files(dev);
+       if (ret)
+               goto add_sysfs_error;
+
+       ret = mdev_add_attribute_group(dev, ops->dev_attr_groups);
+       if (ret)
+               goto add_group_error;
+
+       list_add(&phy_dev->next, &phy_devices.dev_list);
+       dev_info(dev, "MDEV: Registered\n");
+       mutex_unlock(&phy_devices.list_lock);
+
+       return 0;
+
+add_group_error:
+       mdev_remove_sysfs_files(dev);
+add_sysfs_error:
+       mutex_unlock(&phy_devices.list_lock);
+       kfree(phy_dev);
+       return ret;
+}
+EXPORT_SYMBOL(mdev_register_device);
+
+/*
+ * mdev_unregister_device : Unregister a physical device
+ * @dev: device structure representing physical device.
+ *
+ * Remove device from list of registered physical devices. Gives a change to
+ * free existing mediated devices for the given physical device.
+ */
+
+void mdev_unregister_device(struct device *dev)
+{
+       struct phy_device *phy_dev;
+       struct mdev_device *vdev = NULL;
+
+       phy_dev = find_physical_device(dev);
+
+       if (!phy_dev)
+               return;
+
+       dev_info(dev, "MDEV: Unregistering\n");
+
+       while ((vdev = find_next_mdev_device(phy_dev)))
+               mdev_destroy_device(vdev);
+
+       mutex_lock(&phy_devices.list_lock);
+       list_del(&phy_dev->next);
+       mutex_unlock(&phy_devices.list_lock);
+
+       mdev_remove_attribute_group(dev,
+                                   phy_dev->ops->dev_attr_groups);
+
+       mdev_remove_sysfs_files(dev);
+       kfree(phy_dev);
+}
+EXPORT_SYMBOL(mdev_unregister_device);
+
+/*
+ * Functions required for mdev-sysfs
+ */
+
+static struct mdev_device *mdev_device_alloc(uuid_le uuid, int instance)
+{
+       struct mdev_device *mdevice = NULL;
+
+       mdevice = kzalloc(sizeof(*mdevice), GFP_KERNEL);
+       if (!mdevice)
+               return ERR_PTR(-ENOMEM);
+
+       kref_init(&mdevice->kref);
+       memcpy(&mdevice->uuid, &uuid, sizeof(uuid_le));
+       mdevice->instance = instance;
+       mutex_init(&mdevice->ops_lock);
+
+       return mdevice;
+}
+
+static void mdev_device_release(struct device *dev)
+{
+       struct mdev_device *mdevice = to_mdev_device(dev);
+
+       if (!mdevice)
+               return;
+
+       dev_info(&mdevice->dev, "MDEV: destroying\n");
+
+       mutex_lock(&mdevices.list_lock);
+       list_del(&mdevice->next);
+       mutex_unlock(&mdevices.list_lock);
+
+       kfree(mdevice);
+}
+
+int create_mdev_device(struct device *dev, uuid_le uuid, uint32_t instance,
+                      char *mdev_params)
+{
+       int retval = 0;
+       struct mdev_device *mdevice = NULL;
+       struct phy_device *phy_dev;
+
+       phy_dev = find_physical_device(dev);
+       if (!phy_dev)
+               return -EINVAL;
+
+       mdevice = mdev_device_alloc(uuid, instance);
+       if (IS_ERR(mdevice)) {
+               retval = PTR_ERR(mdevice);
+               return retval;
+       }
+
+       mdevice->dev.parent  = dev;
+       mdevice->dev.bus     = &mdev_bus_type;
+       mdevice->dev.release = mdev_device_release;
+       dev_set_name(&mdevice->dev, "%pUb-%d", uuid.b, instance);
+
+       mutex_lock(&mdevices.list_lock);
+       list_add(&mdevice->next, &mdevices.dev_list);
+       mutex_unlock(&mdevices.list_lock);
+
+       retval = device_register(&mdevice->dev);
+       if (retval) {
+               mdev_put_device(mdevice);
+               return retval;
+       }
+
+       mutex_lock(&phy_devices.list_lock);
+       if (phy_dev->ops->create) {
+               retval = phy_dev->ops->create(dev, mdevice->uuid,
+                                             instance, mdev_params);
+               if (retval)
+                       goto create_failed;
+       }
+
+       retval = mdev_add_attribute_group(&mdevice->dev,
+                                         phy_dev->ops->mdev_attr_groups);
+       if (retval)
+               goto create_failed;
+
+       mdevice->phy_dev = phy_dev;
+       mutex_unlock(&phy_devices.list_lock);
+       mdev_get_device(mdevice);
+       dev_info(&mdevice->dev, "MDEV: created\n");
+
+       return retval;
+
+create_failed:
+       mutex_unlock(&phy_devices.list_lock);
+       device_unregister(&mdevice->dev);
+       return retval;
+}
+
+int destroy_mdev_device(uuid_le uuid, uint32_t instance)
+{
+       struct mdev_device *vdev;
+
+       vdev = find_mdev_device(uuid, instance);
+
+       if (!vdev)
+               return -EINVAL;
+
+       mdev_destroy_device(vdev);
+       return 0;
+}
+
+void get_mdev_supported_types(struct device *dev, char *str)
+{
+       struct phy_device *phy_dev;
+
+       phy_dev = find_physical_device(dev);
+
+       if (phy_dev) {
+               mutex_lock(&phy_devices.list_lock);
+               if (phy_dev->ops->supported_config)
+                       phy_dev->ops->supported_config(phy_dev->dev, str);
+               mutex_unlock(&phy_devices.list_lock);
+       }
+}
+
+int mdev_start_callback(uuid_le uuid, uint32_t instance)
+{
+       int ret = 0;
+       struct mdev_device *mdevice;
+       struct phy_device *phy_dev;
+
+       mdevice = find_mdev_device(uuid, instance);
+
+       if (!mdevice)
+               return -EINVAL;
+
+       phy_dev = mdevice->phy_dev;
+
+       mutex_lock(&phy_devices.list_lock);
+       if (phy_dev->ops->start)
+               ret = phy_dev->ops->start(mdevice->uuid);
+       mutex_unlock(&phy_devices.list_lock);
+
+       if (ret < 0)
+               pr_err("mdev_start failed  %d\n", ret);
+       else
+               kobject_uevent(&mdevice->dev.kobj, KOBJ_ONLINE);
+
+       return ret;
+}
+
+int mdev_shutdown_callback(uuid_le uuid, uint32_t instance)
+{
+       int ret = 0;
+       struct mdev_device *mdevice;
+       struct phy_device *phy_dev;
+
+       mdevice = find_mdev_device(uuid, instance);
+
+       if (!mdevice)
+               return -EINVAL;
+
+       phy_dev = mdevice->phy_dev;
+
+       mutex_lock(&phy_devices.list_lock);
+       if (phy_dev->ops->shutdown)
+               ret = phy_dev->ops->shutdown(mdevice->uuid);
+       mutex_unlock(&phy_devices.list_lock);
+
+       if (ret < 0)
+               pr_err("mdev_shutdown failed %d\n", ret);
+       else
+               kobject_uevent(&mdevice->dev.kobj, KOBJ_OFFLINE);
+
+       return ret;
+}
+
+static struct class mdev_class = {
+       .name           = MDEV_CLASS_NAME,
+       .owner          = THIS_MODULE,
+       .class_attrs    = mdev_class_attrs,
+};
+
+static int __init mdev_init(void)
+{
+       int rc = 0;
+
+       mutex_init(&mdevices.list_lock);
+       INIT_LIST_HEAD(&mdevices.dev_list);
+       mutex_init(&phy_devices.list_lock);
+       INIT_LIST_HEAD(&phy_devices.dev_list);
+
+       rc = class_register(&mdev_class);
+       if (rc < 0) {
+               pr_err("Failed to register mdev class\n");
+               return rc;
+       }
+
+       rc = mdev_bus_register();
+       if (rc < 0) {
+               pr_err("Failed to register mdev bus\n");
+               class_unregister(&mdev_class);
+               return rc;
+       }
+
+       return rc;
+}
+
+static void __exit mdev_exit(void)
+{
+       mdev_bus_unregister();
+       class_unregister(&mdev_class);
+}
+
+module_init(mdev_init)
+module_exit(mdev_exit)
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
diff --git a/drivers/vfio/mdev/mdev-driver.c b/drivers/vfio/mdev/mdev-driver.c
new file mode 100644
index 000000000000..bc8a169782bc
--- /dev/null
+++ b/drivers/vfio/mdev/mdev-driver.c
@@ -0,0 +1,139 @@
+/*
+ * MDEV driver
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <address@hidden>
+ *            Kirti Wankhede <address@hidden>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/device.h>
+#include <linux/iommu.h>
+#include <linux/mdev.h>
+
+#include "mdev_private.h"
+
+static int mdevice_attach_iommu(struct mdev_device *mdevice)
+{
+       int retval = 0;
+       struct iommu_group *group = NULL;
+
+       group = iommu_group_alloc();
+       if (IS_ERR(group)) {
+               dev_err(&mdevice->dev, "MDEV: failed to allocate group!\n");
+               return PTR_ERR(group);
+       }
+
+       retval = iommu_group_add_device(group, &mdevice->dev);
+       if (retval) {
+               dev_err(&mdevice->dev, "MDEV: failed to add dev to group!\n");
+               goto attach_fail;
+       }
+
+       mdevice->group = group;
+
+       dev_info(&mdevice->dev, "MDEV: group_id = %d\n",
+                                iommu_group_id(group));
+attach_fail:
+       iommu_group_put(group);
+       return retval;
+}
+
+static void mdevice_detach_iommu(struct mdev_device *mdevice)
+{
+       iommu_group_remove_device(&mdevice->dev);
+       dev_info(&mdevice->dev, "MDEV: detaching iommu\n");
+}
+
+static int mdevice_probe(struct device *dev)
+{
+       struct mdev_driver *drv = to_mdev_driver(dev->driver);
+       struct mdev_device *mdevice = to_mdev_device(dev);
+       int status = 0;
+
+       status = mdevice_attach_iommu(mdevice);
+       if (status) {
+               dev_err(dev, "Failed to attach IOMMU\n");
+               return status;
+       }
+
+       if (drv && drv->probe)
+               status = drv->probe(dev);
+
+       return status;
+}
+
+static int mdevice_remove(struct device *dev)
+{
+       struct mdev_driver *drv = to_mdev_driver(dev->driver);
+       struct mdev_device *mdevice = to_mdev_device(dev);
+
+       if (drv && drv->remove)
+               drv->remove(dev);
+
+       mdevice_detach_iommu(mdevice);
+
+       return 0;
+}
+
+static int mdevice_match(struct device *dev, struct device_driver *drv)
+{
+       int ret = 0;
+       struct mdev_driver *mdrv = to_mdev_driver(drv);
+
+       if (mdrv && mdrv->match)
+               ret = mdrv->match(dev);
+
+       return ret;
+}
+
+struct bus_type mdev_bus_type = {
+       .name           = "mdev",
+       .match          = mdevice_match,
+       .probe          = mdevice_probe,
+       .remove         = mdevice_remove,
+};
+EXPORT_SYMBOL_GPL(mdev_bus_type);
+
+/**
+ * mdev_register_driver - register a new MDEV driver
+ * @drv: the driver to register
+ * @owner: owner module of driver ro register
+ *
+ * Returns a negative value on error, otherwise 0.
+ */
+int mdev_register_driver(struct mdev_driver *drv, struct module *owner)
+{
+       /* initialize common driver fields */
+       drv->driver.name = drv->name;
+       drv->driver.bus = &mdev_bus_type;
+       drv->driver.owner = owner;
+
+       /* register with core */
+       return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL(mdev_register_driver);
+
+/**
+ * mdev_unregister_driver - unregister MDEV driver
+ * @drv: the driver to unregister
+ *
+ */
+void mdev_unregister_driver(struct mdev_driver *drv)
+{
+       driver_unregister(&drv->driver);
+}
+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-sysfs.c b/drivers/vfio/mdev/mdev-sysfs.c
new file mode 100644
index 000000000000..79d351a7a502
--- /dev/null
+++ b/drivers/vfio/mdev/mdev-sysfs.c
@@ -0,0 +1,312 @@
+/*
+ * File attributes for Mediated devices
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <address@hidden>
+ *            Kirti Wankhede <address@hidden>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/sysfs.h>
+#include <linux/ctype.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/uuid.h>
+#include <linux/mdev.h>
+
+#include "mdev_private.h"
+
+/* Prototypes */
+static ssize_t mdev_supported_types_show(struct device *dev,
+                                        struct device_attribute *attr,
+                                        char *buf);
+static DEVICE_ATTR_RO(mdev_supported_types);
+
+static ssize_t mdev_create_store(struct device *dev,
+                                struct device_attribute *attr,
+                                const char *buf, size_t count);
+static DEVICE_ATTR_WO(mdev_create);
+
+static ssize_t mdev_destroy_store(struct device *dev,
+                                 struct device_attribute *attr,
+                                 const char *buf, size_t count);
+static DEVICE_ATTR_WO(mdev_destroy);
+
+/* Static functions */
+
+#define UUID_CHAR_LENGTH       36
+#define UUID_BYTE_LENGTH       16
+
+#define SUPPORTED_TYPE_BUFFER_LENGTH   1024
+
+static inline bool is_uuid_sep(char sep)
+{
+       if (sep == '\n' || sep == '-' || sep == ':' || sep == '\0')
+               return true;
+       return false;
+}
+
+static int uuid_parse(const char *str, uuid_le *uuid)
+{
+       int i;
+
+       if (strlen(str) < UUID_CHAR_LENGTH)
+               return -1;
+
+       for (i = 0; i < UUID_BYTE_LENGTH; i++) {
+               if (!isxdigit(str[0]) || !isxdigit(str[1])) {
+                       pr_err("%s err", __func__);
+                       return -EINVAL;
+               }
+
+               uuid->b[i] = (hex_to_bin(str[0]) << 4) | hex_to_bin(str[1]);
+               str += 2;
+               if (is_uuid_sep(*str))
+                       str++;
+       }
+
+       return 0;
+}
+
+/* Functions */
+static ssize_t mdev_supported_types_show(struct device *dev,
+                                        struct device_attribute *attr,
+                                        char *buf)
+{
+       char *str;
+       ssize_t n;
+
+       str = kzalloc(sizeof(*str) * SUPPORTED_TYPE_BUFFER_LENGTH, GFP_KERNEL);
+       if (!str)
+               return -ENOMEM;
+
+       get_mdev_supported_types(dev, str);
+
+       n = sprintf(buf, "%s\n", str);
+       kfree(str);
+
+       return n;
+}
+
+static ssize_t mdev_create_store(struct device *dev,
+                                struct device_attribute *attr,
+                                const char *buf, size_t count)
+{
+       char *str, *pstr;
+       char *uuid_str, *instance_str, *mdev_params = NULL;
+       uuid_le uuid;
+       uint32_t instance;
+       int ret = 0;
+
+       pstr = str = kstrndup(buf, count, GFP_KERNEL);
+
+       if (!str)
+               return -ENOMEM;
+
+       uuid_str = strsep(&str, ":");
+       if (!uuid_str) {
+               pr_err("mdev_create: Empty UUID string %s\n", buf);
+               ret = -EINVAL;
+               goto create_error;
+       }
+
+       if (!str) {
+               pr_err("mdev_create: mdev instance not present %s\n", buf);
+               ret = -EINVAL;
+               goto create_error;
+       }
+
+       instance_str = strsep(&str, ":");
+       if (!instance_str) {
+               pr_err("mdev_create: Empty instance string %s\n", buf);
+               ret = -EINVAL;
+               goto create_error;
+       }
+
+       ret = kstrtouint(instance_str, 0, &instance);
+       if (ret) {
+               pr_err("mdev_create: mdev instance parsing error %s\n", buf);
+               goto create_error;
+       }
+
+       if (!str) {
+               pr_err("mdev_create: mdev params not specified %s\n", buf);
+               ret = -EINVAL;
+               goto create_error;
+       }
+
+       mdev_params = kstrdup(str, GFP_KERNEL);
+
+       if (!mdev_params) {
+               ret = -EINVAL;
+               goto create_error;
+       }
+
+       if (uuid_parse(uuid_str, &uuid) < 0) {
+               pr_err("mdev_create: UUID parse error %s\n", buf);
+               ret = -EINVAL;
+               goto create_error;
+       }
+
+       if (create_mdev_device(dev, uuid, instance, mdev_params) < 0) {
+               pr_err("mdev_create: Failed to create mdev device\n");
+               ret = -EINVAL;
+               goto create_error;
+       }
+       ret = count;
+
+create_error:
+       kfree(mdev_params);
+       kfree(pstr);
+       return ret;
+}
+
+static ssize_t mdev_destroy_store(struct device *dev,
+                                 struct device_attribute *attr,
+                                 const char *buf, size_t count)
+{
+       char *uuid_str, *str, *pstr;
+       uuid_le uuid;
+       unsigned int instance;
+       int ret;
+
+       str = pstr = kstrndup(buf, count, GFP_KERNEL);
+
+       if (!str)
+               return -ENOMEM;
+
+       uuid_str = strsep(&str, ":");
+       if (!uuid_str) {
+               pr_err("mdev_destroy: Empty UUID string %s\n", buf);
+               ret = -EINVAL;
+               goto destroy_error;
+       }
+
+       if (str == NULL) {
+               pr_err("mdev_destroy: instance not specified %s\n", buf);
+               ret = -EINVAL;
+               goto destroy_error;
+       }
+
+       ret = kstrtouint(str, 0, &instance);
+       if (ret) {
+               pr_err("mdev_destroy: instance parsing error %s\n", buf);
+               goto destroy_error;
+       }
+
+       if (uuid_parse(uuid_str, &uuid) < 0) {
+               pr_err("mdev_destroy: UUID parse error  %s\n", buf);
+               ret = -EINVAL;
+               goto destroy_error;
+       }
+
+       ret = destroy_mdev_device(uuid, instance);
+       if (ret < 0)
+               goto destroy_error;
+
+       ret = count;
+
+destroy_error:
+       kfree(pstr);
+       return ret;
+}
+
+ssize_t mdev_start_store(struct class *class, struct class_attribute *attr,
+                        const char *buf, size_t count)
+{
+       char *uuid_str;
+       uuid_le uuid;
+       int ret = 0;
+
+       uuid_str = kstrndup(buf, count, GFP_KERNEL);
+
+       if (!uuid_str)
+               return -ENOMEM;
+
+       if (uuid_parse(uuid_str, &uuid) < 0) {
+               pr_err("mdev_start: UUID parse error  %s\n", buf);
+               ret = -EINVAL;
+               goto start_error;
+       }
+
+       ret = mdev_start_callback(uuid, 0);
+       if (ret < 0)
+               goto start_error;
+
+       ret = count;
+
+start_error:
+       kfree(uuid_str);
+       return ret;
+}
+
+ssize_t mdev_shutdown_store(struct class *class, struct class_attribute *attr,
+                           const char *buf, size_t count)
+{
+       char *uuid_str;
+       uuid_le uuid;
+       int ret = 0;
+
+       uuid_str = kstrndup(buf, count, GFP_KERNEL);
+
+       if (!uuid_str)
+               return -ENOMEM;
+
+       if (uuid_parse(uuid_str, &uuid) < 0) {
+               pr_err("mdev_shutdown: UUID parse error %s\n", buf);
+               ret = -EINVAL;
+       }
+
+       ret = mdev_shutdown_callback(uuid, 0);
+       if (ret < 0)
+               goto shutdown_error;
+
+       ret = count;
+
+shutdown_error:
+       kfree(uuid_str);
+       return ret;
+
+}
+
+struct class_attribute mdev_class_attrs[] = {
+       __ATTR_WO(mdev_start),
+       __ATTR_WO(mdev_shutdown),
+       __ATTR_NULL
+};
+
+int mdev_create_sysfs_files(struct device *dev)
+{
+       int retval;
+
+       retval = sysfs_create_file(&dev->kobj,
+                                  &dev_attr_mdev_supported_types.attr);
+       if (retval) {
+               pr_err("Failed to create mdev_supported_types sysfs entry\n");
+               return retval;
+       }
+
+       retval = sysfs_create_file(&dev->kobj, &dev_attr_mdev_create.attr);
+       if (retval) {
+               pr_err("Failed to create mdev_create sysfs entry\n");
+               return retval;
+       }
+
+       retval = sysfs_create_file(&dev->kobj, &dev_attr_mdev_destroy.attr);
+       if (retval) {
+               pr_err("Failed to create mdev_destroy sysfs entry\n");
+               return retval;
+       }
+
+       return 0;
+}
+
+void mdev_remove_sysfs_files(struct device *dev)
+{
+       sysfs_remove_file(&dev->kobj, &dev_attr_mdev_supported_types.attr);
+       sysfs_remove_file(&dev->kobj, &dev_attr_mdev_create.attr);
+       sysfs_remove_file(&dev->kobj, &dev_attr_mdev_destroy.attr);
+}
diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
new file mode 100644
index 000000000000..a472310c7749
--- /dev/null
+++ b/drivers/vfio/mdev/mdev_private.h
@@ -0,0 +1,33 @@
+/*
+ * Mediated device interal definitions
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <address@hidden>
+ *            Kirti Wankhede <address@hidden>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef MDEV_PRIVATE_H
+#define MDEV_PRIVATE_H
+
+int  mdev_bus_register(void);
+void mdev_bus_unregister(void);
+
+/* Function prototypes for mdev_sysfs */
+
+extern struct class_attribute mdev_class_attrs[];
+
+int  mdev_create_sysfs_files(struct device *dev);
+void mdev_remove_sysfs_files(struct device *dev);
+
+int  create_mdev_device(struct device *dev, uuid_le uuid, uint32_t instance,
+                       char *mdev_params);
+int  destroy_mdev_device(uuid_le uuid, uint32_t instance);
+void get_mdev_supported_types(struct device *dev, char *str);
+int  mdev_start_callback(uuid_le uuid, uint32_t instance);
+int  mdev_shutdown_callback(uuid_le uuid, uint32_t instance);
+
+#endif /* MDEV_PRIVATE_H */
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
new file mode 100644
index 000000000000..d9633acd85f2
--- /dev/null
+++ b/include/linux/mdev.h
@@ -0,0 +1,224 @@
+/*
+ * Mediated device definition
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <address@hidden>
+ *            Kirti Wankhede <address@hidden>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef MDEV_H
+#define MDEV_H
+
+/* Common Data structures */
+
+struct pci_region_info {
+       uint64_t start;
+       uint64_t size;
+       uint32_t flags;         /*!< VFIO region info flags */
+};
+
+enum mdev_emul_space {
+       EMUL_CONFIG_SPACE,      /*!< PCI configuration space */
+       EMUL_IO,                /*!< I/O register space */
+       EMUL_MMIO               /*!< Memory-mapped I/O space */
+};
+
+struct phy_device;
+
+/*
+ * Mediated device
+ */
+
+struct mdev_device {
+       struct kref             kref;
+       struct device           dev;
+       struct phy_device       *phy_dev;
+       struct iommu_group      *group;
+       void                    *iommu_data;
+       uuid_le                 uuid;
+       uint32_t                instance;
+       void                    *driver_data;
+       struct mutex            ops_lock;
+       struct list_head        next;
+};
+
+
+/**
+ * struct phy_device_ops - Structure to be registered for each physical device
+ * to register the device to mdev module.
+ *
+ * @owner:             The module owner.
+ * @dev_attr_groups:   Default attributes of the physical device.
+ * @mdev_attr_groups:  Default attributes of the mediated device.
+ * @supported_config:  Called to get information about supported types.
+ *                     @dev : device structure of physical device.
+ *                     @config: should return string listing supported config
+ *                     Returns integer: success (0) or error (< 0)
+ * @create:            Called to allocate basic resources in physical device's
+ *                     driver for a particular mediated device
+ *                     @dev: physical pci device structure on which mediated
+ *                           device should be created
+ *                     @uuid: VM's uuid for which VM it is intended to
+ *                     @instance: mediated instance in that VM
+ *                     @mdev_params: extra parameters required by physical
+ *                     device's driver.
+ *                     Returns integer: success (0) or error (< 0)
+ * @destroy:           Called to free resources in physical device's driver for
+ *                     a mediated device instance of that VM.
+ *                     @dev: physical device structure to which this mediated
+ *                           device points to.
+ *                     @uuid: VM's uuid for which the mediated device belongs
+ *                     @instance: mdev instance in that VM
+ *                     Returns integer: success (0) or error (< 0)
+ *                     If VM is running and destroy() is called that means the
+ *                     mdev is being hotunpluged. Return error if VM is running
+ *                     and driver doesn't support mediated device hotplug.
+ * @start:             Called to do initiate mediated device initialization
+ *                     process in physical device's driver when VM boots before
+ *                     qemu starts.
+ *                     @uuid: VM's UUID which is booting.
+ *                     Returns integer: success (0) or error (< 0)
+ * @shutdown:          Called to teardown mediated device related resources for
+ *                     the VM
+ *                     @uuid: VM's UUID which is shutting down .
+ *                     Returns integer: success (0) or error (< 0)
+ * @read:              Read emulation callback
+ *                     @mdev: mediated device structure
+ *                     @buf: read buffer
+ *                     @count: number bytes to read
+ *                     @address_space: specifies for which address
+ *                     space the request is: pci_config_space, IO
+ *                     register space or MMIO space.
+ *                     @pos: offset from base address.
+ *                     Retuns number on bytes read on success or error.
+ * @write:             Write emulation callback
+ *                     @mdev: mediated device structure
+ *                     @buf: write buffer
+ *                     @count: number bytes to be written
+ *                     @address_space: specifies for which address space the
+ *                     request is: pci_config_space, IO register space or MMIO
+ *                     space.
+ *                     @pos: offset from base address.
+ *                     Retuns number on bytes written on success or error.
+ * @set_irqs:          Called to send about interrupts configuration
+ *                     information that VMM sets.
+ *                     @mdev: mediated device structure
+ *                     @flags, index, start, count and *data : same as that of
+ *                     struct vfio_irq_set of VFIO_DEVICE_SET_IRQS API.
+ * @get_region_info:   Called to get BAR size and flags of mediated device.
+ *                     @mdev: mediated device structure
+ *                     @region_index: VFIO region index
+ *                     @region_info: output, returns size and flags of
+ *                                   requested region.
+ *                     Returns integer: success (0) or error (< 0)
+ * @validate_map_request: Validate remap pfn request
+ *                     @mdev: mediated device structure
+ *                     @virtaddr: target user address to start at
+ *                     @pfn: physical address of kernel memory, vendor driver
+ *                           can change if required.
+ *                     @size: size of map area, vendor driver can change the
+ *                            size of map area if desired.
+ *                     @prot: page protection flags for this mapping, vendor
+ *                            driver can change, if required.
+ *                     Returns integer: success (0) or error (< 0)
+ *
+ * Physical device that support mediated device should be registered with mdev
+ * module with phy_device_ops structure.
+ */
+
+struct phy_device_ops {
+       struct module   *owner;
+       const struct attribute_group **dev_attr_groups;
+       const struct attribute_group **mdev_attr_groups;
+
+       int     (*supported_config)(struct device *dev, char *config);
+       int     (*create)(struct device *dev, uuid_le uuid,
+                         uint32_t instance, char *mdev_params);
+       int     (*destroy)(struct device *dev, uuid_le uuid,
+                          uint32_t instance);
+       int     (*start)(uuid_le uuid);
+       int     (*shutdown)(uuid_le uuid);
+       ssize_t (*read)(struct mdev_device *vdev, char *buf, size_t count,
+                       enum mdev_emul_space address_space, loff_t pos);
+       ssize_t (*write)(struct mdev_device *vdev, char *buf, size_t count,
+                        enum mdev_emul_space address_space, loff_t pos);
+       int     (*set_irqs)(struct mdev_device *vdev, uint32_t flags,
+                           unsigned int index, unsigned int start,
+                           unsigned int count, void *data);
+       int     (*get_region_info)(struct mdev_device *vdev, int region_index,
+                                struct pci_region_info *region_info);
+       int     (*validate_map_request)(struct mdev_device *vdev,
+                                       unsigned long virtaddr,
+                                       unsigned long *pfn, unsigned long *size,
+                                       pgprot_t *prot);
+};
+
+/*
+ * Physical Device
+ */
+struct phy_device {
+       struct device                   *dev;
+       const struct phy_device_ops     *ops;
+       struct list_head                next;
+};
+
+/**
+ * struct mdev_driver - Mediated device driver
+ * @name: driver name
+ * @probe: called when new device created
+ * @remove: called when device removed
+ * @match: called when new device or driver is added for this bus. Return 1 if
+ *        given device can be handled by given driver and zero otherwise.
+ * @driver: device driver structure
+ *
+ **/
+struct mdev_driver {
+       const char *name;
+       int  (*probe)(struct device *dev);
+       void (*remove)(struct device *dev);
+       int  (*match)(struct device *dev);
+       struct device_driver driver;
+};
+
+static inline struct mdev_driver *to_mdev_driver(struct device_driver *drv)
+{
+       return drv ? container_of(drv, struct mdev_driver, driver) : NULL;
+}
+
+static inline struct mdev_device *to_mdev_device(struct device *dev)
+{
+       return dev ? container_of(dev, struct mdev_device, dev) : NULL;
+}
+
+static inline struct mdev_device *mdev_get_device(struct mdev_device *vdev)
+{
+       return (vdev && get_device(&vdev->dev)) ? vdev : NULL;
+}
+
+static inline  void mdev_put_device(struct mdev_device *vdev)
+{
+       if (vdev)
+               put_device(&vdev->dev);
+}
+
+extern struct bus_type mdev_bus_type;
+
+#define dev_is_mdev(d) ((d)->bus == &mdev_bus_type)
+
+extern int  mdev_register_device(struct device *dev,
+                                const struct phy_device_ops *ops);
+extern void mdev_unregister_device(struct device *dev);
+
+extern int  mdev_register_driver(struct mdev_driver *drv, struct module 
*owner);
+extern void mdev_unregister_driver(struct mdev_driver *drv);
+
+extern int mdev_map_virtual_bar(uint64_t virt_bar_addr, uint64_t phys_bar_addr,
+                               uint32_t len, uint32_t flags);
+
+extern struct mdev_device *mdev_get_device_by_group(struct iommu_group *group);
+
+#endif /* MDEV_H */
-- 
2.7.0




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