Subject: [PATCH 2/6] mdev: introduce device specific ops

From: Jason Wang <[email-masked]>
Date: Mon, 23 Sep 2019 21:03:27 +0800

Currently, except for the create and remove. The rest of
mdev_parent_ops is designed for vfio-mdev driver only and may not help
for kernel mdev driver. Follow the class id support by previous patch,
this patch introduces device specific ops pointer inside parent ops
which points to device specific ops (e.g vfio ops). This allows the
future drivers like virtio-mdev to implement its own device specific
ops.

Signed-off-by: Jason Wang <[email-masked]>
---
 .../driver-api/vfio-mediated-device.rst       |  4 +-
 MAINTAINERS                                   |  1 +
 drivers/gpu/drm/i915/gvt/kvmgt.c              | 15 +++---
 drivers/s390/cio/vfio_ccw_ops.c               | 15 ++++--
 drivers/s390/crypto/vfio_ap_ops.c             | 11 ++--
 drivers/vfio/mdev/vfio_mdev.c                 | 31 ++++++-----
 include/linux/mdev.h                          | 36 ++-----------
 include/linux/vfio_mdev.h                     | 53 +++++++++++++++++++
 samples/vfio-mdev/mbochs.c                    | 17 +++---
 samples/vfio-mdev/mdpy.c                      | 17 +++---
 samples/vfio-mdev/mtty.c                      | 15 ++++--
 11 files changed, 138 insertions(+), 77 deletions(-)
 create mode 100644 include/linux/vfio_mdev.h

diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
index 0e052072e1d8..3ab00e48212f 100644
--- a/Documentation/driver-api/vfio-mediated-device.rst
+++ b/Documentation/driver-api/vfio-mediated-device.rst
@@ -152,7 +152,9 @@ callbacks per mdev parent device, per mdev type, or any other categorization.
 Vendor drivers are expected to be fully asynchronous in this respect or
 provide their own internal resource protection.)
 
-The callbacks in the mdev_parent_ops structure are as follows:
+The device specific callbacks are referred through device_ops pointer
+in mdev_parent_ops. For vfio-mdev device, its callbacks in device_ops
+are as follows:
 
 * open: open callback of mediated device
 * close: close callback of mediated device
diff --git a/MAINTAINERS b/MAINTAINERS
index b2326dece28e..89832b316500 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17075,6 +17075,7 @@ S:	Maintained
 F:	Documentation/driver-api/vfio-mediated-device.rst
 F:	drivers/vfio/mdev/
 F:	include/linux/mdev.h
+F:	include/linux/vfio_mdev.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 19d51a35f019..8ea86b1e69f1 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -42,6 +42,7 @@
 #include <linux/kvm_host.h>
 #include <linux/vfio.h>
 #include <linux/mdev.h>
+#include <linux/vfio_mdev.h>
 #include <linux/debugfs.h>
 
 #include <linux/nospec.h>
@@ -1600,20 +1601,22 @@ static const struct attribute_group *intel_vgpu_groups[] = {
 	NULL,
 };
 
-static struct mdev_parent_ops intel_vgpu_ops = {
-	.mdev_attr_groups       = intel_vgpu_groups,
-	.create			= intel_vgpu_create,
-	.remove			= intel_vgpu_remove,
-
+static struct vfio_mdev_parent_ops intel_vfio_vgpu_ops = {
 	.open			= intel_vgpu_open,
 	.release		= intel_vgpu_release,
-
 	.read			= intel_vgpu_read,
 	.write			= intel_vgpu_write,
 	.mmap			= intel_vgpu_mmap,
 	.ioctl			= intel_vgpu_ioctl,
 };
 
+static struct mdev_parent_ops intel_vgpu_ops = {
+	.mdev_attr_groups       = intel_vgpu_groups,
+	.create			= intel_vgpu_create,
+	.remove			= intel_vgpu_remove,
+	.device_ops	        = &intel_vfio_vgpu_ops,
+};
+
 static int kvmgt_host_init(struct device *dev, void *gvt, const void *ops)
 {
 	struct attribute **kvm_type_attrs;
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 246ff0f80944..02122bbc213e 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -12,6 +12,7 @@
 
 #include <linux/vfio.h>
 #include <linux/mdev.h>
+#include <linux/vfio_mdev.h>
 #include <linux/nospec.h>
 #include <linux/slab.h>
 
@@ -574,11 +575,7 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
 	}
 }
 
-static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
-	.owner			= THIS_MODULE,
-	.supported_type_groups  = mdev_type_groups,
-	.create			= vfio_ccw_mdev_create,
-	.remove			= vfio_ccw_mdev_remove,
+static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
 	.open			= vfio_ccw_mdev_open,
 	.release		= vfio_ccw_mdev_release,
 	.read			= vfio_ccw_mdev_read,
@@ -586,6 +583,14 @@ static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
 	.ioctl			= vfio_ccw_mdev_ioctl,
 };
 
+static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
+	.owner			= THIS_MODULE,
+	.supported_type_groups  = mdev_type_groups,
+	.create			= vfio_ccw_mdev_create,
+	.remove			= vfio_ccw_mdev_remove,
+	.device_ops		= &vfio_mdev_ops,
+};
+
 int vfio_ccw_mdev_reg(struct subchannel *sch)
 {
 	return mdev_register_vfio_device(&sch->dev, &vfio_ccw_mdev_ops);
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 7487fc39d2c5..4251becc7a6d 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -16,6 +16,7 @@
 #include <linux/bitops.h>
 #include <linux/kvm_host.h>
 #include <linux/module.h>
+#include <linux/vfio_mdev.h>
 #include <asm/kvm.h>
 #include <asm/zcrypt.h>
 
@@ -1280,15 +1281,19 @@ static ssize_t vfio_ap_mdev_ioctl(struct mdev_device *mdev,
 	return ret;
 }
 
+static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
+	.open			= vfio_ap_mdev_open,
+	.release		= vfio_ap_mdev_release,
+	.ioctl			= vfio_ap_mdev_ioctl,
+};
+
 static const struct mdev_parent_ops vfio_ap_matrix_ops = {
 	.owner			= THIS_MODULE,
 	.supported_type_groups	= vfio_ap_mdev_type_groups,
 	.mdev_attr_groups	= vfio_ap_mdev_attr_groups,
 	.create			= vfio_ap_mdev_create,
 	.remove			= vfio_ap_mdev_remove,
-	.open			= vfio_ap_mdev_open,
-	.release		= vfio_ap_mdev_release,
-	.ioctl			= vfio_ap_mdev_ioctl,
+	.device_ops		= &vfio_mdev_ops,
 };
 
 int vfio_ap_mdev_register(void)
diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
index fd2a4d9a3f26..d23c9f58c84f 100644
--- a/drivers/vfio/mdev/vfio_mdev.c
+++ b/drivers/vfio/mdev/vfio_mdev.c
@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/vfio.h>
 #include <linux/mdev.h>
+#include <linux/vfio_mdev.h>
 
 #include "mdev_private.h"
 
@@ -25,15 +26,16 @@ static int vfio_mdev_open(void *device_data)
 {
 	struct mdev_device *mdev = device_data;
 	struct mdev_parent *parent = mdev->parent;
+	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
 	int ret;
 
-	if (unlikely(!parent->ops->open))
+	if (unlikely(!ops->open))
 		return -EINVAL;
 
 	if (!try_module_get(THIS_MODULE))
 		return -ENODEV;
 
-	ret = parent->ops->open(mdev);
+	ret = ops->open(mdev);
 	if (ret)
 		module_put(THIS_MODULE);
 
@@ -44,9 +46,10 @@ static void vfio_mdev_release(void *device_data)
 {
 	struct mdev_device *mdev = device_data;
 	struct mdev_parent *parent = mdev->parent;
+	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
 
-	if (likely(parent->ops->release))
-		parent->ops->release(mdev);
+	if (likely(ops->release))
+		ops->release(mdev);
 
 	module_put(THIS_MODULE);
 }
@@ -56,11 +59,12 @@ static long vfio_mdev_unlocked_ioctl(void *device_data,
 {
 	struct mdev_device *mdev = device_data;
 	struct mdev_parent *parent = mdev->parent;
+	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
 
-	if (unlikely(!parent->ops->ioctl))
+	if (unlikely(!ops->ioctl))
 		return -EINVAL;
 
-	return parent->ops->ioctl(mdev, cmd, arg);
+	return ops->ioctl(mdev, cmd, arg);
 }
 
 static ssize_t vfio_mdev_read(void *device_data, char __user *buf,
@@ -68,11 +72,12 @@ static ssize_t vfio_mdev_read(void *device_data, char __user *buf,
 {
 	struct mdev_device *mdev = device_data;
 	struct mdev_parent *parent = mdev->parent;
+	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
 
-	if (unlikely(!parent->ops->read))
+	if (unlikely(!ops->read))
 		return -EINVAL;
 
-	return parent->ops->read(mdev, buf, count, ppos);
+	return ops->read(mdev, buf, count, ppos);
 }
 
 static ssize_t vfio_mdev_write(void *device_data, const char __user *buf,
@@ -80,22 +85,24 @@ static ssize_t vfio_mdev_write(void *device_data, const char __user *buf,
 {
 	struct mdev_device *mdev = device_data;
 	struct mdev_parent *parent = mdev->parent;
+	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
 
-	if (unlikely(!parent->ops->write))
+	if (unlikely(!ops->write))
 		return -EINVAL;
 
-	return parent->ops->write(mdev, buf, count, ppos);
+	return ops->write(mdev, buf, count, ppos);
 }
 
 static int vfio_mdev_mmap(void *device_data, struct vm_area_struct *vma)
 {
 	struct mdev_device *mdev = device_data;
 	struct mdev_parent *parent = mdev->parent;
+	const struct vfio_mdev_parent_ops *ops = parent->ops->device_ops;
 
-	if (unlikely(!parent->ops->mmap))
+	if (unlikely(!ops->mmap))
 		return -EINVAL;
 
-	return parent->ops->mmap(mdev, vma);
+	return ops->mmap(mdev, vma);
 }
 
 static const struct vfio_device_ops vfio_mdev_dev_ops = {
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 3ebae310f599..fa167bcb81e1 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -48,30 +48,8 @@ struct device *mdev_get_iommu_device(struct device *dev);
  *			@mdev: mdev_device device structure which is being
  *			       destroyed
  *			Returns integer: success (0) or error (< 0)
- * @open:		Open mediated device.
- *			@mdev: mediated device.
- *			Returns integer: success (0) or error (< 0)
- * @release:		release mediated device
- *			@mdev: mediated device.
- * @read:		Read emulation callback
- *			@mdev: mediated device structure
- *			@buf: read buffer
- *			@count: number of bytes to read
- *			@ppos: address.
- *			Retuns number on bytes read on success or error.
- * @write:		Write emulation callback
- *			@mdev: mediated device structure
- *			@buf: write buffer
- *			@count: number of bytes to be written
- *			@ppos: address.
- *			Retuns number on bytes written on success or error.
- * @ioctl:		IOCTL callback
- *			@mdev: mediated device structure
- *			@cmd: ioctl command
- *			@arg: arguments to ioctl
- * @mmap:		mmap callback
- *			@mdev: mediated device structure
- *			@vma: vma structure
+ * @device_ops:         Device specific emulation callback.
+ *
  * Parent device that support mediated device should be registered with mdev
  * module with mdev_parent_ops structure.
  **/
@@ -83,15 +61,7 @@ struct mdev_parent_ops {
 
 	int     (*create)(struct kobject *kobj, struct mdev_device *mdev);
 	int     (*remove)(struct mdev_device *mdev);
-	int     (*open)(struct mdev_device *mdev);
-	void    (*release)(struct mdev_device *mdev);
-	ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
-			size_t count, loff_t *ppos);
-	ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
-			 size_t count, loff_t *ppos);
-	long	(*ioctl)(struct mdev_device *mdev, unsigned int cmd,
-			 unsigned long arg);
-	int	(*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
+	const void *device_ops;
 };
 
 /* interface for exporting mdev supported type attributes */
diff --git a/include/linux/vfio_mdev.h b/include/linux/vfio_mdev.h
new file mode 100644
index 000000000000..0c1b34f98f5d
--- /dev/null
+++ b/include/linux/vfio_mdev.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * VFIO Mediated device definition
+ */
+
+#ifndef VFIO_MDEV_H
+#define VFIO_MDEV_H
+
+#include <linux/types.h>
+#include <linux/mdev.h>
+
+/**
+ * struct vfio_mdev_parent_ops - Structure to be registered for each
+ * parent device to register the device to vfio-mdev module.
+ *
+ * @open:		Open mediated device.
+ *			@mdev: mediated device.
+ *			Returns integer: success (0) or error (< 0)
+ * @release:		release mediated device
+ *			@mdev: mediated device.
+ * @read:		Read emulation callback
+ *			@mdev: mediated device structure
+ *			@buf: read buffer
+ *			@count: number of bytes to read
+ *			@ppos: address.
+ *			Retuns number on bytes read on success or error.
+ * @write:		Write emulation callback
+ *			@mdev: mediated device structure
+ *			@buf: write buffer
+ *			@count: number of bytes to be written
+ *			@ppos: address.
+ *			Retuns number on bytes written on success or error.
+ * @ioctl:		IOCTL callback
+ *			@mdev: mediated device structure
+ *			@cmd: ioctl command
+ *			@arg: arguments to ioctl
+ * @mmap:		mmap callback
+ *			@mdev: mediated device structure
+ *			@vma: vma structure
+ */
+struct vfio_mdev_parent_ops {
+	int     (*open)(struct mdev_device *mdev);
+	void    (*release)(struct mdev_device *mdev);
+	ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
+			size_t count, loff_t *ppos);
+	ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
+			 size_t count, loff_t *ppos);
+	long	(*ioctl)(struct mdev_device *mdev, unsigned int cmd,
+			 unsigned long arg);
+	int	(*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
+};
+
+#endif
diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index 71a4469be85d..107cc30d0f45 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -30,6 +30,7 @@
 #include <linux/iommu.h>
 #include <linux/sysfs.h>
 #include <linux/mdev.h>
+#include <linux/vfio_mdev.h>
 #include <linux/pci.h>
 #include <linux/dma-buf.h>
 #include <linux/highmem.h>
@@ -1418,12 +1419,7 @@ static struct attribute_group *mdev_type_groups[] = {
 	NULL,
 };
 
-static const struct mdev_parent_ops mdev_fops = {
-	.owner			= THIS_MODULE,
-	.mdev_attr_groups	= mdev_dev_groups,
-	.supported_type_groups	= mdev_type_groups,
-	.create			= mbochs_create,
-	.remove			= mbochs_remove,
+static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
 	.open			= mbochs_open,
 	.release		= mbochs_close,
 	.read			= mbochs_read,
@@ -1432,6 +1428,15 @@ static const struct mdev_parent_ops mdev_fops = {
 	.mmap			= mbochs_mmap,
 };
 
+static const struct mdev_parent_ops mdev_fops = {
+	.owner			= THIS_MODULE,
+	.mdev_attr_groups	= mdev_dev_groups,
+	.supported_type_groups	= mdev_type_groups,
+	.create			= mbochs_create,
+	.remove			= mbochs_remove,
+	.device_ops		= &vfio_mdev_ops,
+};
+
 static const struct file_operations vd_fops = {
 	.owner		= THIS_MODULE,
 };
diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
index d3029dd27d91..2cd2018a53f9 100644
--- a/samples/vfio-mdev/mdpy.c
+++ b/samples/vfio-mdev/mdpy.c
@@ -26,6 +26,7 @@
 #include <linux/iommu.h>
 #include <linux/sysfs.h>
 #include <linux/mdev.h>
+#include <linux/vfio_mdev.h>
 #include <linux/pci.h>
 #include <drm/drm_fourcc.h>
 #include "mdpy-defs.h"
@@ -725,12 +726,7 @@ static struct attribute_group *mdev_type_groups[] = {
 	NULL,
 };
 
-static const struct mdev_parent_ops mdev_fops = {
-	.owner			= THIS_MODULE,
-	.mdev_attr_groups	= mdev_dev_groups,
-	.supported_type_groups	= mdev_type_groups,
-	.create			= mdpy_create,
-	.remove			= mdpy_remove,
+static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
 	.open			= mdpy_open,
 	.release		= mdpy_close,
 	.read			= mdpy_read,
@@ -739,6 +735,15 @@ static const struct mdev_parent_ops mdev_fops = {
 	.mmap			= mdpy_mmap,
 };
 
+static const struct mdev_parent_ops mdev_fops = {
+	.owner			= THIS_MODULE,
+	.mdev_attr_groups	= mdev_dev_groups,
+	.supported_type_groups	= mdev_type_groups,
+	.create			= mdpy_create,
+	.remove			= mdpy_remove,
+	.device_ops		= &vfio_mdev_ops,
+};
+
 static const struct file_operations vd_fops = {
 	.owner		= THIS_MODULE,
 };
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index 744c88a6b22c..e427425b5daf 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -27,6 +27,7 @@
 #include <linux/ctype.h>
 #include <linux/file.h>
 #include <linux/mdev.h>
+#include <linux/vfio_mdev.h>
 #include <linux/pci.h>
 #include <linux/serial.h>
 #include <uapi/linux/serial_reg.h>
@@ -1410,6 +1411,14 @@ static struct attribute_group *mdev_type_groups[] = {
 	NULL,
 };
 
+static const struct vfio_mdev_parent_ops vfio_mdev_ops = {
+	.open                   = mtty_open,
+	.release                = mtty_close,
+	.read                   = mtty_read,
+	.write                  = mtty_write,
+	.ioctl		        = mtty_ioctl,
+};
+
 static const struct mdev_parent_ops mdev_fops = {
 	.owner                  = THIS_MODULE,
 	.dev_attr_groups        = mtty_dev_groups,
@@ -1417,11 +1426,7 @@ static const struct mdev_parent_ops mdev_fops = {
 	.supported_type_groups  = mdev_type_groups,
 	.create                 = mtty_create,
 	.remove			= mtty_remove,
-	.open                   = mtty_open,
-	.release                = mtty_close,
-	.read                   = mtty_read,
-	.write                  = mtty_write,
-	.ioctl		        = mtty_ioctl,
+	.device_ops             = &vfio_mdev_ops,
 };
 
 static void mtty_device_release(struct device *dev)
-- 
2.19.1