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/*
*
* Copyright (c) 2009, Microsoft Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
* Place - Suite 330, Boston, MA 02111-1307 USA.
*
* Authors:
* Haiyang Zhang <haiyangz@microsoft.com>
* Hank Janssen <hjanssen@microsoft.com>
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/hyperv.h>
#include <linux/export.h>
#include <asm/hyperv.h>
#include "hyperv_vmbus.h"
struct vmbus_connection vmbus_connection = {
.conn_state = DISCONNECTED,
.next_gpadl_handle = ATOMIC_INIT(0xE1E10),
};
/*
* VMBUS version is 32 bit entity broken up into
* two 16 bit quantities: major_number. minor_number.
*
* 0 . 13 (Windows Server 2008)
* 1 . 1 (Windows 7)
* 2 . 4 (Windows 8)
*/
#define VERSION_WS2008 ((0 << 16) | (13))
#define VERSION_WIN7 ((1 << 16) | (1))
#define VERSION_WIN8 ((2 << 16) | (4))
#define VERSION_INVAL -1
/*
* Negotiated protocol version with the host.
*/
__u32 vmbus_proto_version;
EXPORT_SYMBOL_GPL(vmbus_proto_version);
static __u32 vmbus_get_next_version(__u32 current_version)
{
switch (current_version) {
case (VERSION_WIN7):
return VERSION_WS2008;
case (VERSION_WIN8):
return VERSION_WIN7;
case (VERSION_WS2008):
default:
return VERSION_INVAL;
}
}
static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
__u32 version)
{
int ret = 0;
struct vmbus_channel_initiate_contact *msg;
unsigned long flags;
int t;
init_completion(&msginfo->waitevent);
msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
msg->vmbus_version_requested = version;
msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages);
msg->monitor_page2 = virt_to_phys(
(void *)((unsigned long)vmbus_connection.monitor_pages +
PAGE_SIZE));
/*
* Add to list before we send the request since we may
* receive the response before returning from this routine
*/
spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
list_add_tail(&msginfo->msglistentry,
&vmbus_connection.chn_msg_list);
spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
ret = vmbus_post_msg(msg,
sizeof(struct vmbus_channel_initiate_contact));
if (ret != 0) {
spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
list_del(&msginfo->msglistentry);
spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
flags);
return ret;
}
/* Wait for the connection response */
t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
if (t == 0) {
spin_lock_irqsave(&vmbus_connection.channelmsg_lock,
flags);
list_del(&msginfo->msglistentry);
spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
flags);
return -ETIMEDOUT;
}
spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
list_del(&msginfo->msglistentry);
spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
/* Check if successful */
if (msginfo->response.version_response.version_supported) {
vmbus_connection.conn_state = CONNECTED;
} else {
pr_err("Unable to connect, "
"Version %d not supported by Hyper-V\n",
version);
return -ECONNREFUSED;
}
return ret;
}
/*
* vmbus_connect - Sends a connect request on the partition service connection
*/
int vmbus_connect(void)
{
int ret = 0;
struct vmbus_channel_msginfo *msginfo = NULL;
__u32 version;
/* Initialize the vmbus connection */
vmbus_connection.conn_state = CONNECTING;
vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
if (!vmbus_connection.work_queue) {
ret = -ENOMEM;
goto cleanup;
}
INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
spin_lock_init(&vmbus_connection.channelmsg_lock);
INIT_LIST_HEAD(&vmbus_connection.chn_list);
spin_lock_init(&vmbus_connection.channel_lock);
/*
* Setup the vmbus event connection for channel interrupt
* abstraction stuff
*/
vmbus_connection.int_page =
(void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
if (vmbus_connection.int_page == NULL) {
ret = -ENOMEM;
goto cleanup;
}
vmbus_connection.recv_int_page = vmbus_connection.int_page;
vmbus_connection.send_int_page =
(void *)((unsigned long)vmbus_connection.int_page +
(PAGE_SIZE >> 1));
/*
* Setup the monitor notification facility. The 1st page for
* parent->child and the 2nd page for child->parent
*/
vmbus_connection.monitor_pages =
(void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 1);
if (vmbus_connection.monitor_pages == NULL) {
ret = -ENOMEM;
goto cleanup;
}
msginfo = kzalloc(sizeof(*msginfo) +
sizeof(struct vmbus_channel_initiate_contact),
GFP_KERNEL);
if (msginfo == NULL) {
ret = -ENOMEM;
goto cleanup;
}
/*
* Negotiate a compatible VMBUS version number with the
* host. We start with the highest number we can support
* and work our way down until we negotiate a compatible
* version.
*/
version = VERSION_WS2008;
do {
ret = vmbus_negotiate_version(msginfo, version);
if (ret == 0)
break;
version = vmbus_get_next_version(version);
} while (version != VERSION_INVAL);
if (version == VERSION_INVAL)
goto cleanup;
vmbus_proto_version = version;
pr_info("Negotiated host information %d\n", version);
kfree(msginfo);
return 0;
cleanup:
vmbus_connection.conn_state = DISCONNECTED;
if (vmbus_connection.work_queue)
destroy_workqueue(vmbus_connection.work_queue);
if (vmbus_connection.int_page) {
free_pages((unsigned long)vmbus_connection.int_page, 0);
vmbus_connection.int_page = NULL;
}
if (vmbus_connection.monitor_pages) {
free_pages((unsigned long)vmbus_connection.monitor_pages, 1);
vmbus_connection.monitor_pages = NULL;
}
kfree(msginfo);
return ret;
}
/*
* relid2channel - Get the channel object given its
* child relative id (ie channel id)
*/
struct vmbus_channel *relid2channel(u32 relid)
{
struct vmbus_channel *channel;
struct vmbus_channel *found_channel = NULL;
unsigned long flags;
spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
if (channel->offermsg.child_relid == relid) {
found_channel = channel;
break;
}
}
spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
return found_channel;
}
/*
* process_chn_event - Process a channel event notification
*/
static void process_chn_event(u32 relid)
{
struct vmbus_channel *channel;
unsigned long flags;
void *arg;
bool read_state;
u32 bytes_to_read;
/*
* Find the channel based on this relid and invokes the
* channel callback to process the event
*/
channel = relid2channel(relid);
if (!channel) {
pr_err("channel not found for relid - %u\n", relid);
return;
}
/*
* A channel once created is persistent even when there
* is no driver handling the device. An unloading driver
* sets the onchannel_callback to NULL under the
* protection of the channel inbound_lock. Thus, checking
* and invoking the driver specific callback takes care of
* orderly unloading of the driver.
*/
spin_lock_irqsave(&channel->inbound_lock, flags);
if (channel->onchannel_callback != NULL) {
arg = channel->channel_callback_context;
read_state = channel->batched_reading;
/*
* This callback reads the messages sent by the host.
* We can optimize host to guest signaling by ensuring:
* 1. While reading the channel, we disable interrupts from
* host.
* 2. Ensure that we process all posted messages from the host
* before returning from this callback.
* 3. Once we return, enable signaling from the host. Once this
* state is set we check to see if additional packets are
* available to read. In this case we repeat the process.
*/
do {
hv_begin_read(&channel->inbound);
channel->onchannel_callback(arg);
bytes_to_read = hv_end_read(&channel->inbound);
} while (read_state && (bytes_to_read != 0));
} else {
pr_err("no channel callback for relid - %u\n", relid);
}
spin_unlock_irqrestore(&channel->inbound_lock, flags);
}
/*
* vmbus_on_event - Handler for events
*/
void vmbus_on_event(unsigned long data)
{
u32 dword;
u32 maxdword
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