[PATCH v8 2/6] vfio: VFIO based driver for Mediated devices

Kirti Wankhede
2016-10-10T20:27:39Z

vfio_mdev driver registers with mdev core driver.
MDEV core driver creates mediated device and calls probe routine of
vfio_mdev driver for each device.
Probe routine of vfio_mdev driver adds mediated device to VFIO core module

This driver forms a shim layer that pass through VFIO devices operations
to vendor driver for mediated devices.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Change-Id: I583f4734752971d3d112324d69e2508c88f359ec
---
drivers/vfio/mdev/Kconfig | 6 ++
drivers/vfio/mdev/Makefile | 1 +
drivers/vfio/mdev/vfio_mdev.c | 171 ++++++++++++++++++++++++++++++++++++
drivers/vfio/pci/vfio_pci_private.h | 6 +-
4 files changed, 181 insertions(+), 3 deletions(-)
create mode 100644 drivers/vfio/mdev/vfio_mdev.c

diff --git a/drivers/vfio/mdev/Kconfig b/drivers/vfio/mdev/Kconfig
index 23d5b9d08a5c..e1b23697261d 100644
--- a/drivers/vfio/mdev/Kconfig
+++ b/drivers/vfio/mdev/Kconfig
@@ -9,4 +9,10 @@ config VFIO_MDEV

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

+config VFIO_MDEV_DEVICE
+ tristate "VFIO support for Mediated devices"
+ depends on VFIO && VFIO_MDEV
+ default n
+ help
+ VFIO based driver for mediated devices.

diff --git a/drivers/vfio/mdev/Makefile b/drivers/vfio/mdev/Makefile
index 56a75e689582..e5087ed83a34 100644
--- a/drivers/vfio/mdev/Makefile
+++ b/drivers/vfio/mdev/Makefile
@@ -2,4 +2,5 @@
mdev-y := mdev_core.o mdev_sysfs.o mdev_driver.o

obj-$(CONFIG_VFIO_MDEV) += mdev.o
+obj-$(CONFIG_VFIO_MDEV_DEVICE) += vfio_mdev.o

diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
new file mode 100644
index 000000000000..1efc3f309510
--- /dev/null
+++ b/drivers/vfio/mdev/vfio_mdev.c
@@ -0,0 +1,171 @@
+/*
+ * VFIO based driver for Mediated device
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ * Author: Neo Jia <cjia@nvidia.com>
+ * Kirti Wankhede <kwankhede@nvidia.com>
+ *
+ * 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/slab.h>
+#include <linux/uuid.h>
+#include <linux/vfio.h>
+#include <linux/iommu.h>
+#include <linux/mdev.h>
+
+#include "mdev_private.h"
+
+#define DRIVER_VERSION "0.1"
+#define DRIVER_AUTHOR "NVIDIA Corporation"
+#define DRIVER_DESC "VFIO based driver for Mediated device"
+
+struct vfio_mdev {
+ struct iommu_group *group;
+ struct mdev_device *mdev;
+};
+
+static int vfio_mdev_open(void *device_data)
+{
+ struct vfio_mdev *vmdev = device_data;
+ struct parent_device *parent = vmdev->mdev->parent;
+ int ret;
+
+ if (unlikely(!parent->ops->open))
+ return -EINVAL;
+
+ if (!try_module_get(THIS_MODULE))
+ return -ENODEV;
+
+ ret = parent->ops->open(vmdev->mdev);
+ if (ret)
+ module_put(THIS_MODULE);
+
+ return ret;
+}
+
+static void vfio_mdev_release(void *device_data)
+{
+ struct vfio_mdev *vmdev = device_data;
+ struct parent_device *parent = vmdev->mdev->parent;
+
+ if (parent->ops->release)
+ parent->ops->release(vmdev->mdev);
+
+ module_put(THIS_MODULE);
+}
+
+static long vfio_mdev_unlocked_ioctl(void *device_data,
+ unsigned int cmd, unsigned long arg)
+{
+ struct vfio_mdev *vmdev = device_data;
+ struct parent_device *parent = vmdev->mdev->parent;
+
+ if (unlikely(!parent->ops->ioctl))
+ return -EINVAL;
+
+ return parent->ops->ioctl(vmdev->mdev, cmd, arg);
+}
+
+static ssize_t vfio_mdev_read(void *device_data, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct vfio_mdev *vmdev = device_data;
+ struct parent_device *parent = vmdev->mdev->parent;
+
+ if (unlikely(!parent->ops->read))
+ return -EINVAL;
+
+ return parent->ops->read(vmdev->mdev, buf, count, *ppos);
+}
+
+static ssize_t vfio_mdev_write(void *device_data, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct vfio_mdev *vmdev = device_data;
+ struct parent_device *parent = vmdev->mdev->parent;
+
+ if (unlikely(!parent->ops->write))
+ return -EINVAL;
+
+ return parent->ops->write(vmdev->mdev, (char *)buf, count, *ppos);
+}
+
+static int vfio_mdev_mmap(void *device_data, struct vm_area_struct *vma)
+{
+ struct vfio_mdev *vmdev = device_data;
+ struct parent_device *parent = vmdev->mdev->parent;
+
+ if (unlikely(!parent->ops->mmap))
+ return -EINVAL;
+
+ return parent->ops->mmap(vmdev->mdev, vma);
+}
+
+static const struct vfio_device_ops vfio_mdev_dev_ops = {
+ .name = "vfio-mdev",
+ .open = vfio_mdev_open,
+ .release = vfio_mdev_release,
+ .ioctl = vfio_mdev_unlocked_ioctl,
+ .read = vfio_mdev_read,
+ .write = vfio_mdev_write,
+ .mmap = vfio_mdev_mmap,
+};
+
+int vfio_mdev_probe(struct device *dev)
+{
+ struct vfio_mdev *vmdev;
+ struct mdev_device *mdev = to_mdev_device(dev);
+ int ret;
+
+ vmdev = kzalloc(sizeof(*vmdev), GFP_KERNEL);
+ if (IS_ERR(vmdev))
+ return PTR_ERR(vmdev);
+
+ vmdev->mdev = mdev;
+ vmdev->group = mdev->group;
+
+ ret = vfio_add_group_dev(dev, &vfio_mdev_dev_ops, vmdev);
+ if (ret)
+ kfree(vmdev);
+
+ return ret;
+}
+
+void vfio_mdev_remove(struct device *dev)
+{
+ struct vfio_mdev *vmdev;
+
+ vmdev = vfio_del_group_dev(dev);
+ kfree(vmdev);
+}
+
+struct mdev_driver vfio_mdev_driver = {
+ .name = "vfio_mdev",
+ .probe = vfio_mdev_probe,
+ .remove = vfio_mdev_remove,
+};
+
+static int __init vfio_mdev_init(void)
+{
+ return mdev_register_driver(&vfio_mdev_driver, THIS_MODULE);
+}
+
+static void __exit vfio_mdev_exit(void)
+{
+ mdev_unregister_driver(&vfio_mdev_driver);
+}
+
+module_init(vfio_mdev_init)
+module_exit(vfio_mdev_exit)
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
index 016c14a1b454..776cc2b063d4 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -21,9 +21,9 @@

#define VFIO_PCI_OFFSET_SHIFT 40

-#define VFIO_PCI_OFFSET_TO_INDEX(off) (off >> VFIO_PCI_OFFSET_SHIFT)
-#define VFIO_PCI_INDEX_TO_OFFSET(index) ((u64)(index) << VFIO_PCI_OFFSET_SHIFT)
-#define VFIO_PCI_OFFSET_MASK (((u64)(1) << VFIO_PCI_OFFSET_SHIFT) - 1)
+#define VFIO_PCI_OFFSET_TO_INDEX(off) (off >> VFIO_PCI_OFFSET_SHIFT)
+#define VFIO_PCI_INDEX_TO_OFFSET(index) ((u64)(index) << VFIO_PCI_OFFSET_SHIFT)
+#define VFIO_PCI_OFFSET_MASK (((u64)(1) << VFIO_PCI_OFFSET_SHIFT) - 1)

/* Special capability IDs predefined access */
#define PCI_CAP_ID_INVALID 0xFF /* default raw access */
--
2.7.0