drivers/hid/hid-hyperv.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *  Copyright (c) 2009, Citrix Systems, Inc.
  *  Copyright (c) 2010, Microsoft Corporation.
  *  Copyright (c) 2011, Novell Inc.
  */
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/completion.h>
 #include <linux/input.h>
 #include <linux/hid.h>
 #include <linux/hiddev.h>
 #include <linux/hyperv.h>


 struct hv_input_dev_info {
 	unsigned int size;
 	unsigned short vendor;
 	unsigned short product;
 	unsigned short version;
 	unsigned short reserved[11];
 };

 /* The maximum size of a synthetic input message. */
 #define SYNTHHID_MAX_INPUT_REPORT_SIZE 16

 /*
  * Current version
  *
  * History:
  * Beta, RC < 2008/1/22        1,0
  * RC > 2008/1/22              2,0
  */
 #define SYNTHHID_INPUT_VERSION_MAJOR	2
 #define SYNTHHID_INPUT_VERSION_MINOR	0
 #define SYNTHHID_INPUT_VERSION		(SYNTHHID_INPUT_VERSION_MINOR | \
 					 (SYNTHHID_INPUT_VERSION_MAJOR << 16))


 #pragma pack(push, 1)
 /*
  * Message types in the synthetic input protocol
  */
 enum synthhid_msg_type {
 	SYNTH_HID_PROTOCOL_REQUEST,
 	SYNTH_HID_PROTOCOL_RESPONSE,
 	SYNTH_HID_INITIAL_DEVICE_INFO,
 	SYNTH_HID_INITIAL_DEVICE_INFO_ACK,
 	SYNTH_HID_INPUT_REPORT,
 	SYNTH_HID_MAX
 };

 /*
  * Basic message structures.
  */
 struct synthhid_msg_hdr {
 	enum synthhid_msg_type type;
 	u32 size;
 };

 struct synthhid_msg {
 	struct synthhid_msg_hdr header;
 	char data[1]; /* Enclosed message */
 };

 union synthhid_version {
 	struct {
 		u16 minor_version;
 		u16 major_version;
 	};
 	u32 version;
 };

 /*
  * Protocol messages
  */
 struct synthhid_protocol_request {
 	struct synthhid_msg_hdr header;
 	union synthhid_version version_requested;
 };

 struct synthhid_protocol_response {
 	struct synthhid_msg_hdr header;
 	union synthhid_version version_requested;
 	unsigned char approved;
 };

 struct synthhid_device_info {
 	struct synthhid_msg_hdr header;
 	struct hv_input_dev_info hid_dev_info;
 	struct hid_descriptor hid_descriptor;
 };

 struct synthhid_device_info_ack {
 	struct synthhid_msg_hdr header;
 	unsigned char reserved;
 };

 struct synthhid_input_report {
 	struct synthhid_msg_hdr header;
 	char buffer[1];
 };

 #pragma pack(pop)

 #define INPUTVSC_SEND_RING_BUFFER_SIZE	VMBUS_RING_SIZE(36 * 1024)
 #define INPUTVSC_RECV_RING_BUFFER_SIZE	VMBUS_RING_SIZE(36 * 1024)


 enum pipe_prot_msg_type {
 	PIPE_MESSAGE_INVALID,
 	PIPE_MESSAGE_DATA,
 	PIPE_MESSAGE_MAXIMUM
 };


 struct pipe_prt_msg {
 	enum pipe_prot_msg_type type;
 	u32 size;
 	char data[1];
 };

 struct  mousevsc_prt_msg {
 	enum pipe_prot_msg_type type;
 	u32 size;
 	union {
 		struct synthhid_protocol_request request;
 		struct synthhid_protocol_response response;
 		struct synthhid_device_info_ack ack;
 	};
 };

 /*
  * Represents an mousevsc device
  */
 struct mousevsc_dev {
 	struct hv_device	*device;
 	bool			init_complete;
 	bool			connected;
 	struct mousevsc_prt_msg	protocol_req;
 	struct mousevsc_prt_msg	protocol_resp;
 	/* Synchronize the request/response if needed */
 	struct completion	wait_event;
 	int			dev_info_status;

 	struct hid_descriptor	*hid_desc;
 	unsigned char		*report_desc;
 	u32			report_desc_size;
 	struct hv_input_dev_info hid_dev_info;
 	struct hid_device       *hid_device;
 	u8			input_buf[HID_MAX_BUFFER_SIZE];
 };


 static struct mousevsc_dev *mousevsc_alloc_device(struct hv_device *device)
 {
 	struct mousevsc_dev *input_dev;

 	input_dev = kzalloc(sizeof(struct mousevsc_dev), GFP_KERNEL);

 	if (!input_dev)
 		return NULL;

 	input_dev->device = device;
 	hv_set_drvdata(device, input_dev);
 	init_completion(&input_dev->wait_event);
 	input_dev->init_complete = false;

 	return input_dev;
 }

 static void mousevsc_free_device(struct mousevsc_dev *device)
 {
 	kfree(device->hid_desc);
 	kfree(device->report_desc);
 	hv_set_drvdata(device->device, NULL);
 	kfree(device);
 }

 static void mousevsc_on_receive_device_info(struct mousevsc_dev *input_device,
 				struct synthhid_device_info *device_info)
 {
 	int ret = 0;
 	struct hid_descriptor *desc;
 	struct mousevsc_prt_msg ack;

 	input_device->dev_info_status = -ENOMEM;

 	input_device->hid_dev_info = device_info->hid_dev_info;
 	desc = &device_info->hid_descriptor;
 	if (desc->bLength == 0)
 		goto cleanup;

 	/* The pointer is not NULL when we resume from hibernation */
 	kfree(input_device->hid_desc);
 	input_device->hid_desc = kmemdup(desc, desc->bLength, GFP_ATOMIC);

 	if (!input_device->hid_desc)
 		goto cleanup;

 	input_device->report_desc_size = le16_to_cpu(
 					desc->desc[0].wDescriptorLength);
 	if (input_device->report_desc_size == 0) {
 		input_device->dev_info_status = -EINVAL;
 		goto cleanup;
 	}

 	/* The pointer is not NULL when we resume from hibernation */
 	kfree(input_device->report_desc);
 	input_device->report_desc = kzalloc(input_device->report_desc_size,
 					  GFP_ATOMIC);

 	if (!input_device->report_desc) {
 		input_device->dev_info_status = -ENOMEM;
 		goto cleanup;
 	}

 	memcpy(input_device->report_desc,
 	       ((unsigned char *)desc) + desc->bLength,
 	       le16_to_cpu(desc->desc[0].wDescriptorLength));

 	/* Send the ack */
 	memset(&ack, 0, sizeof(struct mousevsc_prt_msg));

 	ack.type = PIPE_MESSAGE_DATA;
 	ack.size = sizeof(struct synthhid_device_info_ack);

 	ack.ack.header.type = SYNTH_HID_INITIAL_DEVICE_INFO_ACK;
 	ack.ack.header.size = 1;
 	ack.ack.reserved = 0;

 	ret = vmbus_sendpacket(input_device->device->channel,
 			&ack,
 			sizeof(struct pipe_prt_msg) - sizeof(unsigned char) +
 			sizeof(struct synthhid_device_info_ack),
 			(unsigned long)&ack,
 			VM_PKT_DATA_INBAND,
 			VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);

 	if (!ret)
 		input_device->dev_info_status = 0;

 cleanup:
 	complete(&input_device->wait_event);

 	return;
 }

 static void mousevsc_on_receive(struct hv_device *device,
 				struct vmpacket_descriptor *packet)
 {
 	struct pipe_prt_msg *pipe_msg;
 	struct synthhid_msg *hid_msg;
 	struct mousevsc_dev *input_dev = hv_get_drvdata(device);
 	struct synthhid_input_report *input_report;
 	size_t len;

 	pipe_msg = (struct pipe_prt_msg *)((unsigned long)packet +
 						(packet->offset8 << 3));

 	if (pipe_msg->type != PIPE_MESSAGE_DATA)
 		return;

 	hid_msg = (struct synthhid_msg *)pipe_msg->data;

 	switch (hid_msg->header.type) {
 	case SYNTH_HID_PROTOCOL_RESPONSE:
 		/*
 		 * While it will be impossible for us to protect against
 		 * malicious/buggy hypervisor/host, add a check here to
 		 * ensure we don't corrupt memory.
 		 */
 		if ((pipe_msg->size + sizeof(struct pipe_prt_msg)
 			- sizeof(unsigned char))
 			> sizeof(struct mousevsc_prt_msg)) {
 			WARN_ON(1);
 			break;
 		}

 		memcpy(&input_dev->protocol_resp, pipe_msg,
 		       pipe_msg->size + sizeof(struct pipe_prt_msg) -
 		       sizeof(unsigned char));
 		complete(&input_dev->wait_event);
 		break;

 	case SYNTH_HID_INITIAL_DEVICE_INFO:
 		WARN_ON(pipe_msg->size < sizeof(struct hv_input_dev_info));

 		/*
 		 * Parse out the device info into device attr,
 		 * hid desc and report desc
 		 */
 		mousevsc_on_receive_device_info(input_dev,
 			(struct synthhid_device_info *)pipe_msg->data);
 		break;
 	case SYNTH_HID_INPUT_REPORT:
 		input_report =
 			(struct synthhid_input_report *)pipe_msg->data;
 		if (!input_dev->init_complete)
 			break;

 		len = min(input_report->header.size,
 			  (u32)sizeof(input_dev->input_buf));
 		memcpy(input_dev->input_buf, input_report->buffer, len);
 		hid_input_report(input_dev->hid_device, HID_INPUT_REPORT,
 				 input_dev->input_buf, len, 1);

 		pm_wakeup_hard_event(&input_dev->device->device);

 		break;
 	default:
 		pr_err("unsupported hid msg type - type %d len %d\n",
 		       hid_msg->header.type, hid_msg->header.size);
 		break;
 	}

 }

 static void mousevsc_on_channel_callback(void *context)
 {
 	struct hv_device *device = context;
 	struct vmpacket_descriptor *desc;

 	foreach_vmbus_pkt(desc, device->channel) {
 		switch (desc->type) {
 		case VM_PKT_COMP:
 			break;

 		case VM_PKT_DATA_INBAND:
 			mousevsc_on_receive(device, desc);
 			break;

 		default:
 			pr_err("Unhandled packet type %d, tid %llx len %d\n",
 			       desc->type, desc->trans_id, desc->len8 * 8);
 			break;
 		}
 	}
 }

 static int mousevsc_connect_to_vsp(struct hv_device *device)
 {
 	int ret = 0;
 	unsigned long t;
 	struct mousevsc_dev *input_dev = hv_get_drvdata(device);
 	struct mousevsc_prt_msg *request;
 	struct mousevsc_prt_msg *response;

 	reinit_completion(&input_dev->wait_event);

 	request = &input_dev->protocol_req;
 	memset(request, 0, sizeof(struct mousevsc_prt_msg));

 	request->type = PIPE_MESSAGE_DATA;
 	request->size = sizeof(struct synthhid_protocol_request);
 	request->request.header.type = SYNTH_HID_PROTOCOL_REQUEST;
 	request->request.header.size = sizeof(unsigned int);
 	request->request.version_requested.version = SYNTHHID_INPUT_VERSION;

 	ret = vmbus_sendpacket(device->channel, request,
 				sizeof(struct pipe_prt_msg) -
 				sizeof(unsigned char) +
 				sizeof(struct synthhid_protocol_request),
 				(unsigned long)request,
 				VM_PKT_DATA_INBAND,
 				VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 	if (ret)
 		goto cleanup;

 	t = wait_for_completion_timeout(&input_dev->wait_event, 5*HZ);
 	if (!t) {
 		ret = -ETIMEDOUT;
 		goto cleanup;
 	}

 	response = &input_dev->protocol_resp;

 	if (!response->response.approved) {
 		pr_err("synthhid protocol request failed (version %d)\n",
 		       SYNTHHID_INPUT_VERSION);
 		ret = -ENODEV;
 		goto cleanup;
 	}

 	t = wait_for_completion_timeout(&input_dev->wait_event, 5*HZ);
 	if (!t) {
 		ret = -ETIMEDOUT;
 		goto cleanup;
 	}

 	/*
 	 * We should have gotten the device attr, hid desc and report
 	 * desc at this point
 	 */
 	ret = input_dev->dev_info_status;

 cleanup:
 	return ret;
 }

 static int mousevsc_hid_parse(struct hid_device *hid)
 {
 	struct hv_device *dev = hid_get_drvdata(hid);
 	struct mousevsc_dev *input_dev = hv_get_drvdata(dev);

 	return hid_parse_report(hid, input_dev->report_desc,
 				input_dev->report_desc_size);
 }

 static int mousevsc_hid_open(struct hid_device *hid)
 {
 	return 0;
 }

 static int mousevsc_hid_start(struct hid_device *hid)
 {
 	return 0;
 }

 static void mousevsc_hid_close(struct hid_device *hid)
 {
 }

 static void mousevsc_hid_stop(struct hid_device *hid)
 {
 }

 static int mousevsc_hid_raw_request(struct hid_device *hid,
 				    unsigned char report_num,
 				    __u8 *buf, size_t len,
 				    unsigned char rtype,
 				    int reqtype)
 {
 	return 0;
 }

 static struct hid_ll_driver mousevsc_ll_driver = {
 	.parse = mousevsc_hid_parse,
 	.open = mousevsc_hid_open,
 	.close = mousevsc_hid_close,
 	.start = mousevsc_hid_start,
 	.stop = mousevsc_hid_stop,
 	.raw_request = mousevsc_hid_raw_request,
 };

 static struct hid_driver mousevsc_hid_driver;

 static int mousevsc_probe(struct hv_device *device,
 			const struct hv_vmbus_device_id *dev_id)
 {
 	int ret;
 	struct mousevsc_dev *input_dev;
 	struct hid_device *hid_dev;

 	input_dev = mousevsc_alloc_device(device);

 	if (!input_dev)
 		return -ENOMEM;

 	ret = vmbus_open(device->channel,
 		INPUTVSC_SEND_RING_BUFFER_SIZE,
 		INPUTVSC_RECV_RING_BUFFER_SIZE,
 		NULL,
 		0,
 		mousevsc_on_channel_callback,
 		device
 		);

 	if (ret)
 		goto probe_err0;

 	ret = mousevsc_connect_to_vsp(device);

 	if (ret)
 		goto probe_err1;

 	/* workaround SA-167 */
 	if (input_dev->report_desc[14] == 0x25)
 		input_dev->report_desc[14] = 0x29;

 	hid_dev = hid_allocate_device();
 	if (IS_ERR(hid_dev)) {
 		ret = PTR_ERR(hid_dev);
 		goto probe_err1;
 	}

 	hid_dev->ll_driver = &mousevsc_ll_driver;
 	hid_dev->driver = &mousevsc_hid_driver;
 	hid_dev->bus = BUS_VIRTUAL;
 	hid_dev->vendor = input_dev->hid_dev_info.vendor;
 	hid_dev->product = input_dev->hid_dev_info.product;
 	hid_dev->version = input_dev->hid_dev_info.version;
 	input_dev->hid_device = hid_dev;

 	sprintf(hid_dev->name, "%s", "Microsoft Vmbus HID-compliant Mouse");

 	hid_set_drvdata(hid_dev, device);

 	ret = hid_add_device(hid_dev);
 	if (ret)
 		goto probe_err1;


 	ret = hid_parse(hid_dev);
 	if (ret) {
 		hid_err(hid_dev, "parse failed\n");
 		goto probe_err2;
 	}

 	ret = hid_hw_start(hid_dev, HID_CONNECT_HIDINPUT | HID_CONNECT_HIDDEV);

 	if (ret) {
 		hid_err(hid_dev, "hw start failed\n");
 		goto probe_err2;
 	}

 	device_init_wakeup(&device->device, true);

 	input_dev->connected = true;
 	input_dev->init_complete = true;

 	return ret;

 probe_err2:
 	hid_destroy_device(hid_dev);

 probe_err1:
 	vmbus_close(device->channel);

 probe_err0:
 	mousevsc_free_device(input_dev);

 	return ret;
 }


 static int mousevsc_remove(struct hv_device *dev)
 {
 	struct mousevsc_dev *input_dev = hv_get_drvdata(dev);

 	device_init_wakeup(&dev->device, false);
 	vmbus_close(dev->channel);
 	hid_hw_stop(input_dev->hid_device);
 	hid_destroy_device(input_dev->hid_device);
 	mousevsc_free_device(input_dev);

 	return 0;
 }

 static int mousevsc_suspend(struct hv_device *dev)
 {
 	vmbus_close(dev->channel);

 	return 0;
 }

 static int mousevsc_resume(struct hv_device *dev)
 {
 	int ret;

 	ret = vmbus_open(dev->channel,
 			 INPUTVSC_SEND_RING_BUFFER_SIZE,
 			 INPUTVSC_RECV_RING_BUFFER_SIZE,
 			 NULL, 0,
 			 mousevsc_on_channel_callback,
 			 dev);
 	if (ret)
 		return ret;

 	ret = mousevsc_connect_to_vsp(dev);
 	return ret;
 }

 static const struct hv_vmbus_device_id id_table[] = {
 	/* Mouse guid */
 	{ HV_MOUSE_GUID, },
 	{ },
 };

 MODULE_DEVICE_TABLE(vmbus, id_table);

 static struct  hv_driver mousevsc_drv = {
 	.name = KBUILD_MODNAME,
 	.id_table = id_table,
 	.probe = mousevsc_probe,
 	.remove = mousevsc_remove,
 	.suspend = mousevsc_suspend,
 	.resume = mousevsc_resume,
 	.driver = {
 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
 	},
 };

 static int __init mousevsc_init(void)
 {
 	return vmbus_driver_register(&mousevsc_drv);
 }

 static void __exit mousevsc_exit(void)
 {
 	vmbus_driver_unregister(&mousevsc_drv);
 }

 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Microsoft Hyper-V Synthetic HID Driver");

 module_init(mousevsc_init);
 module_exit(mousevsc_exit);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (c) 2009, Citrix Systems, Inc.
	* Copyright (c) 2010, Microsoft Corporation.
	* Copyright (c) 2011, Novell Inc.
	*/
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/device.h>
	#include <linux/completion.h>
	#include <linux/input.h>
	#include <linux/hid.h>
	#include <linux/hiddev.h>
	#include <linux/hyperv.h>


	struct hv_input_dev_info {
	unsigned int size;
	unsigned short vendor;
	unsigned short product;
	unsigned short version;
	unsigned short reserved[11];
	};

	/* The maximum size of a synthetic input message. */
	#define SYNTHHID_MAX_INPUT_REPORT_SIZE 16

	/*
	* Current version
	*
	* History:
	* Beta, RC < 2008/1/22 1,0
	* RC > 2008/1/22 2,0
	*/
	#define SYNTHHID_INPUT_VERSION_MAJOR 2
	#define SYNTHHID_INPUT_VERSION_MINOR 0
	#define SYNTHHID_INPUT_VERSION (SYNTHHID_INPUT_VERSION_MINOR \| \
	(SYNTHHID_INPUT_VERSION_MAJOR << 16))


	#pragma pack(push, 1)
	/*
	* Message types in the synthetic input protocol
	*/
	enum synthhid_msg_type {
	SYNTH_HID_PROTOCOL_REQUEST,
	SYNTH_HID_PROTOCOL_RESPONSE,
	SYNTH_HID_INITIAL_DEVICE_INFO,
	SYNTH_HID_INITIAL_DEVICE_INFO_ACK,
	SYNTH_HID_INPUT_REPORT,
	SYNTH_HID_MAX
	};

	/*
	* Basic message structures.
	*/
	struct synthhid_msg_hdr {
	enum synthhid_msg_type type;
	u32 size;
	};

	struct synthhid_msg {
	struct synthhid_msg_hdr header;
	char data[1]; /* Enclosed message */
	};

	union synthhid_version {
	struct {
	u16 minor_version;
	u16 major_version;
	};
	u32 version;
	};

	/*
	* Protocol messages
	*/
	struct synthhid_protocol_request {
	struct synthhid_msg_hdr header;
	union synthhid_version version_requested;
	};

	struct synthhid_protocol_response {
	struct synthhid_msg_hdr header;
	union synthhid_version version_requested;
	unsigned char approved;
	};

	struct synthhid_device_info {
	struct synthhid_msg_hdr header;
	struct hv_input_dev_info hid_dev_info;
	struct hid_descriptor hid_descriptor;
	};

	struct synthhid_device_info_ack {
	struct synthhid_msg_hdr header;
	unsigned char reserved;
	};

	struct synthhid_input_report {
	struct synthhid_msg_hdr header;
	char buffer[1];
	};

	#pragma pack(pop)

	#define INPUTVSC_SEND_RING_BUFFER_SIZE VMBUS_RING_SIZE(36 * 1024)
	#define INPUTVSC_RECV_RING_BUFFER_SIZE VMBUS_RING_SIZE(36 * 1024)


	enum pipe_prot_msg_type {
	PIPE_MESSAGE_INVALID,
	PIPE_MESSAGE_DATA,
	PIPE_MESSAGE_MAXIMUM
	};


	struct pipe_prt_msg {
	enum pipe_prot_msg_type type;
	u32 size;
	char data[1];
	};

	struct mousevsc_prt_msg {
	enum pipe_prot_msg_type type;
	u32 size;
	union {
	struct synthhid_protocol_request request;
	struct synthhid_protocol_response response;
	struct synthhid_device_info_ack ack;
	};
	};

	/*
	* Represents an mousevsc device
	*/
	struct mousevsc_dev {
	struct hv_device *device;
	bool init_complete;
	bool connected;
	struct mousevsc_prt_msg protocol_req;
	struct mousevsc_prt_msg protocol_resp;
	/* Synchronize the request/response if needed */
	struct completion wait_event;
	int dev_info_status;

	struct hid_descriptor *hid_desc;
	unsigned char *report_desc;
	u32 report_desc_size;
	struct hv_input_dev_info hid_dev_info;
	struct hid_device *hid_device;
	u8 input_buf[HID_MAX_BUFFER_SIZE];
	};


	static struct mousevsc_dev mousevsc_alloc_device(struct hv_device device)
	{
	struct mousevsc_dev *input_dev;

	input_dev = kzalloc(sizeof(struct mousevsc_dev), GFP_KERNEL);

	if (!input_dev)
	return NULL;

	input_dev->device = device;
	hv_set_drvdata(device, input_dev);
	init_completion(&input_dev->wait_event);
	input_dev->init_complete = false;

	return input_dev;
	}

	static void mousevsc_free_device(struct mousevsc_dev *device)
	{
	kfree(device->hid_desc);
	kfree(device->report_desc);
	hv_set_drvdata(device->device, NULL);
	kfree(device);
	}

	static void mousevsc_on_receive_device_info(struct mousevsc_dev *input_device,
	struct synthhid_device_info *device_info)
	{
	int ret = 0;
	struct hid_descriptor *desc;
	struct mousevsc_prt_msg ack;

	input_device->dev_info_status = -ENOMEM;

	input_device->hid_dev_info = device_info->hid_dev_info;
	desc = &device_info->hid_descriptor;
	if (desc->bLength == 0)
	goto cleanup;

	/* The pointer is not NULL when we resume from hibernation */
	kfree(input_device->hid_desc);
	input_device->hid_desc = kmemdup(desc, desc->bLength, GFP_ATOMIC);

	if (!input_device->hid_desc)
	goto cleanup;

	input_device->report_desc_size = le16_to_cpu(
	desc->desc[0].wDescriptorLength);
	if (input_device->report_desc_size == 0) {
	input_device->dev_info_status = -EINVAL;
	goto cleanup;
	}

	/* The pointer is not NULL when we resume from hibernation */
	kfree(input_device->report_desc);
	input_device->report_desc = kzalloc(input_device->report_desc_size,
	GFP_ATOMIC);

	if (!input_device->report_desc) {
	input_device->dev_info_status = -ENOMEM;
	goto cleanup;
	}

	memcpy(input_device->report_desc,
	((unsigned char *)desc) + desc->bLength,
	le16_to_cpu(desc->desc[0].wDescriptorLength));

	/* Send the ack */
	memset(&ack, 0, sizeof(struct mousevsc_prt_msg));

	ack.type = PIPE_MESSAGE_DATA;
	ack.size = sizeof(struct synthhid_device_info_ack);

	ack.ack.header.type = SYNTH_HID_INITIAL_DEVICE_INFO_ACK;
	ack.ack.header.size = 1;
	ack.ack.reserved = 0;

	ret = vmbus_sendpacket(input_device->device->channel,
	&ack,
	sizeof(struct pipe_prt_msg) - sizeof(unsigned char) +
	sizeof(struct synthhid_device_info_ack),
	(unsigned long)&ack,
	VM_PKT_DATA_INBAND,
	VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);

	if (!ret)
	input_device->dev_info_status = 0;

	cleanup:
	complete(&input_device->wait_event);

	return;
	}

	static void mousevsc_on_receive(struct hv_device *device,
	struct vmpacket_descriptor *packet)
	{
	struct pipe_prt_msg *pipe_msg;
	struct synthhid_msg *hid_msg;
	struct mousevsc_dev *input_dev = hv_get_drvdata(device);
	struct synthhid_input_report *input_report;
	size_t len;

	pipe_msg = (struct pipe_prt_msg *)((unsigned long)packet +
	(packet->offset8 << 3));

	if (pipe_msg->type != PIPE_MESSAGE_DATA)
	return;

	hid_msg = (struct synthhid_msg *)pipe_msg->data;

	switch (hid_msg->header.type) {
	case SYNTH_HID_PROTOCOL_RESPONSE:
	/*
	* While it will be impossible for us to protect against
	* malicious/buggy hypervisor/host, add a check here to
	* ensure we don't corrupt memory.
	*/
	if ((pipe_msg->size + sizeof(struct pipe_prt_msg)
	- sizeof(unsigned char))
	> sizeof(struct mousevsc_prt_msg)) {
	WARN_ON(1);
	break;
	}

	memcpy(&input_dev->protocol_resp, pipe_msg,
	pipe_msg->size + sizeof(struct pipe_prt_msg) -
	sizeof(unsigned char));
	complete(&input_dev->wait_event);
	break;

	case SYNTH_HID_INITIAL_DEVICE_INFO:
	WARN_ON(pipe_msg->size < sizeof(struct hv_input_dev_info));

	/*
	* Parse out the device info into device attr,
	* hid desc and report desc
	*/
	mousevsc_on_receive_device_info(input_dev,
	(struct synthhid_device_info *)pipe_msg->data);
	break;
	case SYNTH_HID_INPUT_REPORT:
	input_report =
	(struct synthhid_input_report *)pipe_msg->data;
	if (!input_dev->init_complete)
	break;

	len = min(input_report->header.size,
	(u32)sizeof(input_dev->input_buf));
	memcpy(input_dev->input_buf, input_report->buffer, len);
	hid_input_report(input_dev->hid_device, HID_INPUT_REPORT,
	input_dev->input_buf, len, 1);

	pm_wakeup_hard_event(&input_dev->device->device);

	break;
	default:
	pr_err("unsupported hid msg type - type %d len %d\n",
	hid_msg->header.type, hid_msg->header.size);
	break;
	}

	}

	static void mousevsc_on_channel_callback(void *context)
	{
	struct hv_device *device = context;
	struct vmpacket_descriptor *desc;

	foreach_vmbus_pkt(desc, device->channel) {
	switch (desc->type) {
	case VM_PKT_COMP:
	break;

	case VM_PKT_DATA_INBAND:
	mousevsc_on_receive(device, desc);
	break;

	default:
	pr_err("Unhandled packet type %d, tid %llx len %d\n",
	desc->type, desc->trans_id, desc->len8 * 8);
	break;
	}
	}
	}

	static int mousevsc_connect_to_vsp(struct hv_device *device)
	{
	int ret = 0;
	unsigned long t;
	struct mousevsc_dev *input_dev = hv_get_drvdata(device);
	struct mousevsc_prt_msg *request;
	struct mousevsc_prt_msg *response;

	reinit_completion(&input_dev->wait_event);

	request = &input_dev->protocol_req;
	memset(request, 0, sizeof(struct mousevsc_prt_msg));

	request->type = PIPE_MESSAGE_DATA;
	request->size = sizeof(struct synthhid_protocol_request);
	request->request.header.type = SYNTH_HID_PROTOCOL_REQUEST;
	request->request.header.size = sizeof(unsigned int);
	request->request.version_requested.version = SYNTHHID_INPUT_VERSION;

	ret = vmbus_sendpacket(device->channel, request,
	sizeof(struct pipe_prt_msg) -
	sizeof(unsigned char) +
	sizeof(struct synthhid_protocol_request),
	(unsigned long)request,
	VM_PKT_DATA_INBAND,
	VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
	if (ret)
	goto cleanup;

	t = wait_for_completion_timeout(&input_dev->wait_event, 5*HZ);
	if (!t) {
	ret = -ETIMEDOUT;
	goto cleanup;
	}

	response = &input_dev->protocol_resp;

	if (!response->response.approved) {
	pr_err("synthhid protocol request failed (version %d)\n",
	SYNTHHID_INPUT_VERSION);
	ret = -ENODEV;
	goto cleanup;
	}

	t = wait_for_completion_timeout(&input_dev->wait_event, 5*HZ);
	if (!t) {
	ret = -ETIMEDOUT;
	goto cleanup;
	}

	/*
	* We should have gotten the device attr, hid desc and report
	* desc at this point
	*/
	ret = input_dev->dev_info_status;

	cleanup:
	return ret;
	}

	static int mousevsc_hid_parse(struct hid_device *hid)
	{
	struct hv_device *dev = hid_get_drvdata(hid);
	struct mousevsc_dev *input_dev = hv_get_drvdata(dev);

	return hid_parse_report(hid, input_dev->report_desc,
	input_dev->report_desc_size);
	}

	static int mousevsc_hid_open(struct hid_device *hid)
	{
	return 0;
	}

	static int mousevsc_hid_start(struct hid_device *hid)
	{
	return 0;
	}

	static void mousevsc_hid_close(struct hid_device *hid)
	{
	}

	static void mousevsc_hid_stop(struct hid_device *hid)
	{
	}

	static int mousevsc_hid_raw_request(struct hid_device *hid,
	unsigned char report_num,
	__u8 *buf, size_t len,
	unsigned char rtype,
	int reqtype)
	{
	return 0;
	}

	static struct hid_ll_driver mousevsc_ll_driver = {
	.parse = mousevsc_hid_parse,
	.open = mousevsc_hid_open,
	.close = mousevsc_hid_close,
	.start = mousevsc_hid_start,
	.stop = mousevsc_hid_stop,
	.raw_request = mousevsc_hid_raw_request,
	};

	static struct hid_driver mousevsc_hid_driver;

	static int mousevsc_probe(struct hv_device *device,
	const struct hv_vmbus_device_id *dev_id)
	{
	int ret;
	struct mousevsc_dev *input_dev;
	struct hid_device *hid_dev;

	input_dev = mousevsc_alloc_device(device);

	if (!input_dev)
	return -ENOMEM;

	ret = vmbus_open(device->channel,
	INPUTVSC_SEND_RING_BUFFER_SIZE,
	INPUTVSC_RECV_RING_BUFFER_SIZE,
	NULL,
	0,
	mousevsc_on_channel_callback,
	device
	);

	if (ret)
	goto probe_err0;

	ret = mousevsc_connect_to_vsp(device);

	if (ret)
	goto probe_err1;

	/* workaround SA-167 */
	if (input_dev->report_desc[14] == 0x25)
	input_dev->report_desc[14] = 0x29;

	hid_dev = hid_allocate_device();
	if (IS_ERR(hid_dev)) {
	ret = PTR_ERR(hid_dev);
	goto probe_err1;
	}

	hid_dev->ll_driver = &mousevsc_ll_driver;
	hid_dev->driver = &mousevsc_hid_driver;
	hid_dev->bus = BUS_VIRTUAL;
	hid_dev->vendor = input_dev->hid_dev_info.vendor;
	hid_dev->product = input_dev->hid_dev_info.product;
	hid_dev->version = input_dev->hid_dev_info.version;
	input_dev->hid_device = hid_dev;

	sprintf(hid_dev->name, "%s", "Microsoft Vmbus HID-compliant Mouse");

	hid_set_drvdata(hid_dev, device);

	ret = hid_add_device(hid_dev);
	if (ret)
	goto probe_err1;


	ret = hid_parse(hid_dev);
	if (ret) {
	hid_err(hid_dev, "parse failed\n");
	goto probe_err2;
	}

	ret = hid_hw_start(hid_dev, HID_CONNECT_HIDINPUT \| HID_CONNECT_HIDDEV);

	if (ret) {
	hid_err(hid_dev, "hw start failed\n");
	goto probe_err2;
	}

	device_init_wakeup(&device->device, true);

	input_dev->connected = true;
	input_dev->init_complete = true;

	return ret;

	probe_err2:
	hid_destroy_device(hid_dev);

	probe_err1:
	vmbus_close(device->channel);

	probe_err0:
	mousevsc_free_device(input_dev);

	return ret;
	}


	static int mousevsc_remove(struct hv_device *dev)
	{
	struct mousevsc_dev *input_dev = hv_get_drvdata(dev);

	device_init_wakeup(&dev->device, false);
	vmbus_close(dev->channel);
	hid_hw_stop(input_dev->hid_device);
	hid_destroy_device(input_dev->hid_device);
	mousevsc_free_device(input_dev);

	return 0;
	}

	static int mousevsc_suspend(struct hv_device *dev)
	{
	vmbus_close(dev->channel);

	return 0;
	}

	static int mousevsc_resume(struct hv_device *dev)
	{
	int ret;

	ret = vmbus_open(dev->channel,
	INPUTVSC_SEND_RING_BUFFER_SIZE,
	INPUTVSC_RECV_RING_BUFFER_SIZE,
	NULL, 0,
	mousevsc_on_channel_callback,
	dev);
	if (ret)
	return ret;

	ret = mousevsc_connect_to_vsp(dev);
	return ret;
	}

	static const struct hv_vmbus_device_id id_table[] = {
	/* Mouse guid */
	{ HV_MOUSE_GUID, },
	{ },
	};

	MODULE_DEVICE_TABLE(vmbus, id_table);

	static struct hv_driver mousevsc_drv = {
	.name = KBUILD_MODNAME,
	.id_table = id_table,
	.probe = mousevsc_probe,
	.remove = mousevsc_remove,
	.suspend = mousevsc_suspend,
	.resume = mousevsc_resume,
	.driver = {
	.probe_type = PROBE_PREFER_ASYNCHRONOUS,
	},
	};

	static int __init mousevsc_init(void)
	{
	return vmbus_driver_register(&mousevsc_drv);
	}

	static void __exit mousevsc_exit(void)
	{
	vmbus_driver_unregister(&mousevsc_drv);
	}

	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("Microsoft Hyper-V Synthetic HID Driver");

	module_init(mousevsc_init);
	module_exit(mousevsc_exit);