// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2013, Microsoft Corporation.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/completion.h>
#include <linux/hyperv.h>
#include <linux/serio.h>
#include <linux/slab.h>
/*
* Current version 1.0
*
*/
#define SYNTH_KBD_VERSION_MAJOR 1
#define SYNTH_KBD_VERSION_MINOR 0
#define SYNTH_KBD_VERSION (SYNTH_KBD_VERSION_MINOR | \
(SYNTH_KBD_VERSION_MAJOR << 16))
/*
* Message types in the synthetic input protocol
*/
enum synth_kbd_msg_type {
SYNTH_KBD_PROTOCOL_REQUEST = 1,
SYNTH_KBD_PROTOCOL_RESPONSE = 2,
SYNTH_KBD_EVENT = 3,
SYNTH_KBD_LED_INDICATORS = 4,
};
/*
* Basic message structures.
*/
struct synth_kbd_msg_hdr {
__le32 type;
};
struct synth_kbd_msg {
struct synth_kbd_msg_hdr header;
char data[]; /* Enclosed message */
};
union synth_kbd_version {
__le32 version;
};
/*
* Protocol messages
*/
struct synth_kbd_protocol_request {
struct synth_kbd_msg_hdr header;
union synth_kbd_version version_requested;
};
#define PROTOCOL_ACCEPTED BIT(0)
struct synth_kbd_protocol_response {
struct synth_kbd_msg_hdr header;
__le32 proto_status;
};
#define IS_UNICODE BIT(0)
#define IS_BREAK BIT(1)
#define IS_E0 BIT(2)
#define IS_E1 BIT(3)
struct synth_kbd_keystroke {
struct synth_kbd_msg_hdr header;
__le16 make_code;
__le16 reserved0;
__le32 info; /* Additional information */
};
#define HK_MAXIMUM_MESSAGE_SIZE 256
#define KBD_VSC_SEND_RING_BUFFER_SIZE VMBUS_RING_SIZE(36 * 1024)
#define KBD_VSC_RECV_RING_BUFFER_SIZE VMBUS_RING_SIZE(36 * 1024)
#define XTKBD_EMUL0 0xe0
#define XTKBD_EMUL1 0xe1
#define XTKBD_RELEASE 0x80
/*
* Represents a keyboard device
*/
struct hv_kbd_dev {
struct hv_device *hv_dev;
struct serio *hv_serio;
struct synth_kbd_protocol_request protocol_req;
struct synth_kbd_protocol_response protocol_resp;
/* Synchronize the request/response if needed */
struct completion wait_event;
spinlock_t lock; /* protects 'started' field */
bool started;
};
static void hv_kbd_on_receive(struct hv_device *hv_dev,
struct synth_kbd_msg *msg, u32 msg_length)
{
struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev);
struct synth_kbd_keystroke *ks_msg;
unsigned long flags;
u32 msg_type = __le32_to_cpu(msg->header.type);
u32 info;
u16 scan_code;
switch (msg_type) {
case SYNTH_KBD_PROTOCOL_RESPONSE:
/*
* Validate the information provided by the host.
* If the host is giving us a bogus packet,
* drop the packet (hoping the problem
* goes away).
*/
if (msg_length < sizeof(struct synth_kbd_protocol_response)) {
dev_err(&hv_dev->device,
"Illegal protocol response packet (len: %d)\n",
msg_length);
break;
}
memcpy(&kbd_dev->protocol_resp, msg,
sizeof(struct synth_kbd_protocol_response));
complete(&kbd_dev->wait_event);
break;
case SYNTH_KBD_EVENT:
/*
* Validate the information provided by the host.
* If the host is giving us a bogus packet,
* drop the packet (hoping the problem
* goes away).
*/
if (msg_length < sizeof(struct synth_kbd_keystroke)) {
dev_err(&hv_dev->device,
"Illegal keyboard event packet (len: %d)\n",
msg_length);
break;
}
ks_msg = (struct synth_kbd_keystroke *)msg;
info = __le32_to_cpu(ks_msg->info);
/*
* Inject the information through the serio interrupt.
*/
spin_lock_irqsave(&kbd_dev->lock, flags);
if (kbd_dev->started) {
if (info & IS_E0)
serio_interrupt(kbd_dev->hv_serio,
XTKBD_EMUL0, 0);
if (info & IS_E1)
serio_interrupt(kbd_dev->hv_serio,
XTKBD_EMUL1, 0);
scan_code = __le16_to_cpu(ks_msg->make_code);
if (info & IS_BREAK)
scan_code |= XTKBD_RELEASE;
serio_interrupt(kbd_dev->hv_serio, scan_code, 0);
}
spin_unlock_irqrestore(&kbd_dev->lock, flags);
/*
* Only trigger a wakeup on key down, otherwise
* "echo freeze > /sys/power/state" can't really enter the
* state because the Enter-UP can trigger a wakeup at once.
*/
if (!(info & IS_BREAK))
pm_wakeup_hard_event(&hv_dev->device);
break;
default:
dev_err(&hv_dev->device,
"unhandled message type %d\n", msg_type);
}
}
static void hv_kbd_handle_received_packet(struct hv_device *hv_dev,
struct vmpacket_descriptor *desc,
u32 bytes_recvd,
u64 req_id)
{
struct synth_kbd_msg *msg;
u32 msg_sz;
switch (desc->type) {
case VM_PKT_COMP:
break;
case VM_PKT_DATA_INBAND:
/*
* We have a packet that has "inband" data. The API used
* for retrieving the packet guarantees that the complete
* packet is read. So, minimally, we should be able to
* parse the payload header safely (assuming that the host
* can be trusted. Trusting the host seems to be a
* reasonable assumption because in a virtualized
* environment there is not whole lot you can do if you
* don't trust the host.
*
* Nonetheless, let us validate if the host can be trusted
* (in a trivial way). The interesting aspect of this
* validation is how do you recover if we discover that the
* host is not to be trusted? Simply dropping the packet, I
* don't think is an appropriate recovery. In the interest
* of failing fast, it may be better to crash the guest.
* For now, I will just drop the packet!
*/
msg_sz = bytes_recvd - (desc->offset8 << 3);
if (msg_sz <= sizeof(struct synth_kbd_msg_hdr)) {
/*
* Drop the packet and hope
* the problem magically goes away.
*/
dev_err(&hv_dev->device,
"Illegal packet (type: %d, tid: %llx, size: %d)\n",
desc->type, req_id, msg_sz);
break;
}
msg = (void *)desc + (desc->offset8 << 3);
hv_kbd_on_receive(hv_dev, msg, msg_sz);
break;
default:
dev_err(&hv_dev->device,
"unhandled packet type %d, tid %llx len %d\n",
desc->type, req_id, bytes_recvd);
break;
}
}
static void hv_kbd_on_channel_callback(void *context)
{
struct vmpacket_descriptor *desc;
struct hv_device *hv_dev = context;
u32 bytes_recvd;
u64 req_id;
foreach_vmbus_pkt(desc, hv_dev->channel) {
bytes_recvd = desc->len8 * 8;
req_id = desc->trans_id;
hv_kbd_handle_received_packet(hv_dev, desc, bytes_recvd,
req_id);
}
}
static int hv_kbd_connect_to_vsp(struct hv_device *hv_dev)
{
struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev);
struct synth_kbd_protocol_request *request;
struct synth_kbd_protocol_response *response;
u32 proto_status;
int error;
reinit_completion(&kbd_dev->wait_event);
request = &kbd_dev->protocol_req;
memset(request, 0, sizeof(struct synth_kbd_protocol_request));
request->header.type = __cpu_to_le32(SYNTH_KBD_PROTOCOL_REQUEST);
request->version_requested.version = __cpu_to_le32(SYNTH_KBD_VERSION);
error = vmbus_sendpacket(hv_dev->channel, request,
sizeof(struct synth_kbd_protocol_request),
(unsigned long)request,
VM_PKT_DATA_INBAND,
VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
if (error)
return error;
if (!wait_for_completion_timeout(&kbd_dev->wait_event, 10 * HZ))
return -ETIMEDOUT;
response = &kbd_dev->protocol_resp;
proto_status = __le32_to_cpu(response->proto_status);
if (!(proto_status & PROTOCOL_ACCEPTED)) {
dev_err(&hv_dev->device,
"synth_kbd protocol request failed (version %d)\n",
SYNTH_KBD_VERSION);
return -ENODEV;
}
return 0;
}
static int hv_kbd_start(struct serio *serio)
{
struct hv_kbd_dev *kbd_dev = serio->port_data;
unsigned long flags;
spin_lock_irqsave(&kbd_dev->lock, flags);
kbd_dev->started = true;
spin_unlock_irqrestore(&kbd_dev->lock, flags);
return 0;
}
static void hv_kbd_stop(struct serio *serio)
{
struct hv_kbd_dev *kbd_dev = serio->port_data;
unsigned long flags;
spin_lock_irqsave(&kbd_dev->lock, flags);
kbd_dev->started = false;
spin_unlock_irqrestore(&kbd_dev->lock, flags);
}
static int hv_kbd_probe(struct hv_device *hv_dev,
const struct hv_vmbus_device_id *dev_id)
{
struct hv_kbd_dev *kbd_dev;
struct serio *hv_serio;
int error;
kbd_dev = kzalloc(sizeof(*kbd_dev), GFP_KERNEL);
hv_serio = kzalloc(sizeof(*hv_serio), GFP_KERNEL);
if (!kbd_dev || !hv_serio) {
error = -ENOMEM;
goto err_free_mem;
}
kbd_dev->hv_dev = hv_dev;
kbd_dev->hv_serio = hv_serio;
spin_lock_init(&kbd_dev->lock);
init_completion(&kbd_dev->wait_event);
hv_set_drvdata(hv_dev, kbd_dev);
hv_serio->dev.parent = &hv_dev->device;
hv_serio->id.type = SERIO_8042_XL;
hv_serio->port_data = kbd_dev;
strscpy(hv_serio->name, dev_name(&hv_dev->device),
sizeof(hv_serio->name));
strscpy(hv_serio->phys, dev_name(&hv_dev->device),
sizeof(hv_serio->phys));
hv_serio->start = hv_kbd_start;
hv_serio->stop = hv_kbd_stop;
error = vmbus_open(hv_dev->channel,
KBD_VSC_SEND_RING_BUFFER_SIZE,
KBD_VSC_RECV_RING_BUFFER_SIZE,
NULL, 0,
hv_kbd_on_channel_callback,
hv_dev);
if (error)
goto err_free_mem;
error = hv_kbd_connect_to_vsp(hv_dev);
if (error)
goto err_close_vmbus;
serio_register_port(kbd_dev->hv_serio);
device_init_wakeup(&hv_dev->device, true);
return 0;
err_close_vmbus:
vmbus_close(hv_dev->channel);
err_free_mem:
kfree(hv_serio);
kfree(kbd_dev);
return error;
}
static void hv_kbd_remove(struct hv_device *hv_dev)
{
struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev);
serio_unregister_port(kbd_dev->hv_serio);
vmbus_close(hv_dev->channel);
kfree(kbd_dev);
hv_set_drvdata(hv_dev, NULL);
}
static int hv_kbd_suspend(struct hv_device *hv_dev)
{
vmbus_close(hv_dev->channel);
return 0;
}
static int hv_kbd_resume(struct hv_device *hv_dev)
{
int ret;
ret = vmbus_open(hv_dev->channel,
KBD_VSC_SEND_RING_BUFFER_SIZE,
KBD_VSC_RECV_RING_BUFFER_SIZE,
NULL, 0,
hv_kbd_on_channel_callback,
hv_dev);
if (ret == 0)
ret = hv_kbd_connect_to_vsp(hv_dev);
return ret;
}
static const struct hv_vmbus_device_id id_table[] = {
/* Keyboard guid */
{ HV_KBD_GUID, },
{ },
};
MODULE_DEVICE_TABLE(vmbus, id_table);
static struct hv_driver hv_kbd_drv = {
.name = KBUILD_MODNAME,
.id_table = id_table,
.probe = hv_kbd_probe,
.remove = hv_kbd_remove,
.suspend = hv_kbd_suspend,
.resume = hv_kbd_resume,
.driver = {
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
},
};
static int __init hv_kbd_init(void)
{
return vmbus_driver_register(&hv_kbd_drv);
}
static void __exit hv_kbd_exit(void)
{
vmbus_driver_unregister(&hv_kbd_drv);
}
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Microsoft Hyper-V Synthetic Keyboard Driver");
module_init(hv_kbd_init);
module_exit(hv_kbd_exit);
Codebase Browser
linux