/*
*
* 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),
};
/*
* 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_WIN8_1):
return VERSION_WIN8;
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;
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[0]);
msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
if (version == VERSION_WIN8_1)
msg->target_vcpu = hv_context.vp_index[smp_processor_id()];
/*
* 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 */
wait_for_completion(&msginfo->waitevent);
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 {
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[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
if ((vmbus_connection.monitor_pages[0] == NULL) ||
(vmbus_connection.monitor_pages[1] == 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_CURRENT;
do {
ret = vmbus_negotiate_version(msginfo, version);
if (ret == -ETIMEDOUT)
goto cleanup;
if (vmbus_connection.conn_state == CONNECTED)
break;
version = vmbus_get_next_version(version);
} while (version != VERSION_INVAL);
if (version == VERSION_INVAL)
goto cleanup;
vmbus_proto_version = version;
pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n",
host_info_eax, host_info_ebx >> 16,
host_info_ebx & 0xFFFF, host_info_ecx,
host_info_edx >> 24, host_info_edx & 0xFFFFFF,
version >> 16, version & 0xFFFF);
kfree(msginfo);
return 0;
cleanup:
pr_err("Unable to connect to host\n");
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;
}
free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
vmbus_connection.monitor_pages[0] = NULL;
vmbus_connection.monitor_pages[1] = NULL;
kfree(msginfo);
return ret;
}
/*
* Map the given relid to the corresponding channel based on the
* per-cpu list of channels that have been affinitized to this CPU.
* This will be used in the channel callback path as we can do this
* mapping in a lock-free fashion.
*/
static struct vmbus_channel *pcpu_relid2channel(u32 relid)
{
struct vmbus_channel *channel;
struct vmbus_channel *found_channel = NULL;
int cpu = smp_processor_id();
struct list_head *pcpu_head = &hv_context.percpu_list[cpu];
list_for_each_entry(channel, pcpu_head, percpu_list) {
if (channel->offermsg.child_relid == relid) {
found_channel = channel;
break;
}
}
return found_channel;
}
/*
* 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;
struct list_head *cur, *tmp;
struct vmbus_channel *cur_sc;
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;
} else if (!list_empty(&channel->sc_list)) {
/*
* Deal with sub-channels.
*/
list_for_each_safe(cur, tmp, &channel->sc_list) {
cur_sc = list_entry(cur, struct vmbus_channel,
sc_list);
if (cur_sc->offermsg.child_relid == relid) {
found_channel = cur_sc;
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;
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 = pcpu_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 on the same CPU
* as where this interrupt is handled (in an interrupt context).
* Thus, checking and invoking the driver specific callback takes
* care of orderly unloading of the driver.
*/
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 {
if (read_state)
hv_begin_read(&channel->inbound);
channel->onchannel_callback(arg);
if (read_state)
bytes_to_read = hv_end_read(&channel->inbound);
else
bytes_to_read = 0;
} while (read_state && (bytes_to_read != 0));
} else {
pr_err("no channel callback for relid - %u\n", relid);
}
}
/*
* vmbus_on_event - Handler for events
*/
void vmbus_on_event(unsigned long data)
{
u32 dword;
u32 maxdword;
int bit;
u32 relid;
u32 *recv_int_page = NULL;
void *page_addr;
int cpu = smp_processor_id();
union hv_synic_event_flags *event;
if ((vmbus_proto_version == VERSION_WS2008) ||
(vmbus_proto_version == VERSION_WIN7)) {
maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
recv_int_page = vmbus_connection.recv_int_page;
} else {
/*
* When the host is win8 and beyond, the event page
* can be directly checked to get the id of the channel
* that has the interrupt pending.
*/
maxdword = HV_EVENT_FLAGS_DWORD_COUNT;
page_addr = hv_context.synic_event_page[cpu];
event = (union hv_synic_event_flags *)page_addr +
VMBUS_MESSAGE_SINT;
recv_int_page = event->flags32;
}
/* Check events */
if (!recv_int_page)
return;
for (dword = 0; dword < maxdword; dword++) {
if (!recv_int_page[dword])
continue;
for (bit = 0; bit < 32; bit++) {
if (sync_test_and_clear_bit(bit,
(unsigned long *)&recv_int_page[dword])) {
relid = (dword << 5) + bit;
if (relid == 0)
/*
* Special case - vmbus
* channel protocol msg
*/
continue;
process_chn_event(relid);
}
}
}
}
/*
* vmbus_post_msg - Send a msg on the vmbus's message connection
*/
int vmbus_post_msg(void *buffer, size_t buflen)
{
union hv_connection_id conn_id;
int ret = 0;
int retries = 0;
conn_id.asu32 = 0;
conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
/*
* hv_post_message() can have transient failures because of
* insufficient resources. Retry the operation a couple of
* times before giving up.
*/
while (retries < 10) {
ret = hv_post_message(conn_id, 1, buffer, buflen);
switch (ret) {
case HV_STATUS_INSUFFICIENT_BUFFERS:
ret = -ENOMEM;
case -ENOMEM:
break;
case HV_STATUS_SUCCESS:
return ret;
default:
pr_err("hv_post_msg() failed; error code:%d\n", ret);
return -EINVAL;
}
retries++;
msleep(100);
}
return ret;
}
/*
* vmbus_set_event - Send an event notification to the parent
*/
int vmbus_set_event(struct vmbus_channel *channel)
{
u32 child_relid = channel->offermsg.child_relid;
if (!channel->is_dedicated_interrupt) {
/* Each u32 represents 32 channels */
sync_set_bit(child_relid & 31,
(unsigned long *)vmbus_connection.send_int_page +
(child_relid >> 5));
}
return hv_signal_event(channel->sig_event);
}
