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linux/drivers/hv/vmbus_drv.c
Kimberly Brown 14948e3944 Drivers: hv: vmbus: Fix race condition with new ring_buffer_info mutex 
Fix a race condition that can result in a ring buffer pointer being set
to null while a "_show" function is reading the ring buffer's data. This
problem was discussed here: https://lkml.org/lkml/2018/10/18/779

To fix the race condition, add a new mutex lock to the
"hv_ring_buffer_info" struct. Add a new function,
"hv_ringbuffer_pre_init()", where a channel's inbound and outbound
ring_buffer_info mutex locks are initialized.

Acquire/release the locks in the "hv_ringbuffer_cleanup()" function,
which is where the ring buffer pointers are set to null.

Acquire/release the locks in the four channel-level "_show" functions
that access ring buffer data. Remove the "const" qualifier from the
"vmbus_channel" parameter and the "rbi" variable of the channel-level
"_show" functions so that the locks can be acquired/released in these
functions.

Acquire/release the locks in hv_ringbuffer_get_debuginfo(). Remove the
"const" qualifier from the "hv_ring_buffer_info" parameter so that the
locks can be acquired/released in this function.

Signed-off-by: Kimberly Brown <kimbrownkd@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-04-10 18:58:56 -04:00

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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>
* K. Y. Srinivasan <kys@microsoft.com>
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/sysctl.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/completion.h>
#include <linux/hyperv.h>
#include <linux/kernel_stat.h>
#include <linux/clockchips.h>
#include <linux/cpu.h>
#include <linux/sched/task_stack.h>
#include <asm/mshyperv.h>
#include <linux/notifier.h>
#include <linux/ptrace.h>
#include <linux/screen_info.h>
#include <linux/kdebug.h>
#include <linux/efi.h>
#include <linux/random.h>
#include "hyperv_vmbus.h"
struct vmbus_dynid {
struct list_head node;
struct hv_vmbus_device_id id;
};
static struct acpi_device *hv_acpi_dev;
static struct completion probe_event;
static int hyperv_cpuhp_online;
static void *hv_panic_page;
static int hyperv_panic_event(struct notifier_block *nb, unsigned long val,
void *args)
{
struct pt_regs *regs;
regs = current_pt_regs();
hyperv_report_panic(regs, val);
return NOTIFY_DONE;
}
static int hyperv_die_event(struct notifier_block *nb, unsigned long val,
void *args)
{
struct die_args *die = (struct die_args *)args;
struct pt_regs *regs = die->regs;
hyperv_report_panic(regs, val);
return NOTIFY_DONE;
}
static struct notifier_block hyperv_die_block = {
.notifier_call = hyperv_die_event,
};
static struct notifier_block hyperv_panic_block = {
.notifier_call = hyperv_panic_event,
};
static const char *fb_mmio_name = "fb_range";
static struct resource *fb_mmio;
static struct resource *hyperv_mmio;
static DEFINE_SEMAPHORE(hyperv_mmio_lock);
static int vmbus_exists(void)
{
if (hv_acpi_dev == NULL)
return -ENODEV;
return 0;
}
#define VMBUS_ALIAS_LEN ((sizeof((struct hv_vmbus_device_id *)0)->guid) * 2)
static void print_alias_name(struct hv_device *hv_dev, char *alias_name)
{
int i;
for (i = 0; i < VMBUS_ALIAS_LEN; i += 2)
sprintf(&alias_name[i], "%02x", hv_dev->dev_type.b[i/2]);
}
static u8 channel_monitor_group(const struct vmbus_channel *channel)
{
return (u8)channel->offermsg.monitorid / 32;
}
static u8 channel_monitor_offset(const struct vmbus_channel *channel)
{
return (u8)channel->offermsg.monitorid % 32;
}
static u32 channel_pending(const struct vmbus_channel *channel,
const struct hv_monitor_page *monitor_page)
{
u8 monitor_group = channel_monitor_group(channel);
return monitor_page->trigger_group[monitor_group].pending;
}
static u32 channel_latency(const struct vmbus_channel *channel,
const struct hv_monitor_page *monitor_page)
{
u8 monitor_group = channel_monitor_group(channel);
u8 monitor_offset = channel_monitor_offset(channel);
return monitor_page->latency[monitor_group][monitor_offset];
}
static u32 channel_conn_id(struct vmbus_channel *channel,
struct hv_monitor_page *monitor_page)
{
u8 monitor_group = channel_monitor_group(channel);
u8 monitor_offset = channel_monitor_offset(channel);
return monitor_page->parameter[monitor_group][monitor_offset].connectionid.u.id;
}
static ssize_t id_show(struct device *dev, struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
if (!hv_dev->channel)
return -ENODEV;
return sprintf(buf, "%d\n", hv_dev->channel->offermsg.child_relid);
}
static DEVICE_ATTR_RO(id);
static ssize_t state_show(struct device *dev, struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
if (!hv_dev->channel)
return -ENODEV;
return sprintf(buf, "%d\n", hv_dev->channel->state);
}
static DEVICE_ATTR_RO(state);
static ssize_t monitor_id_show(struct device *dev,
struct device_attribute *dev_attr, char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
if (!hv_dev->channel)
return -ENODEV;
return sprintf(buf, "%d\n", hv_dev->channel->offermsg.monitorid);
}
static DEVICE_ATTR_RO(monitor_id);
static ssize_t class_id_show(struct device *dev,
struct device_attribute *dev_attr, char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
if (!hv_dev->channel)
return -ENODEV;
return sprintf(buf, "{%pUl}\n",
hv_dev->channel->offermsg.offer.if_type.b);
}
static DEVICE_ATTR_RO(class_id);
static ssize_t device_id_show(struct device *dev,
struct device_attribute *dev_attr, char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
if (!hv_dev->channel)
return -ENODEV;
return sprintf(buf, "{%pUl}\n",
hv_dev->channel->offermsg.offer.if_instance.b);
}
static DEVICE_ATTR_RO(device_id);
static ssize_t modalias_show(struct device *dev,
struct device_attribute *dev_attr, char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
char alias_name[VMBUS_ALIAS_LEN + 1];
print_alias_name(hv_dev, alias_name);
return sprintf(buf, "vmbus:%s\n", alias_name);
}
static DEVICE_ATTR_RO(modalias);
#ifdef CONFIG_NUMA
static ssize_t numa_node_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
if (!hv_dev->channel)
return -ENODEV;
return sprintf(buf, "%d\n", hv_dev->channel->numa_node);
}
static DEVICE_ATTR_RO(numa_node);
#endif
static ssize_t server_monitor_pending_show(struct device *dev,
struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
if (!hv_dev->channel)
return -ENODEV;
return sprintf(buf, "%d\n",
channel_pending(hv_dev->channel,
vmbus_connection.monitor_pages[0]));
}
static DEVICE_ATTR_RO(server_monitor_pending);
static ssize_t client_monitor_pending_show(struct device *dev,
struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
if (!hv_dev->channel)
return -ENODEV;
return sprintf(buf, "%d\n",
channel_pending(hv_dev->channel,
vmbus_connection.monitor_pages[1]));
}
static DEVICE_ATTR_RO(client_monitor_pending);
static ssize_t server_monitor_latency_show(struct device *dev,
struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
if (!hv_dev->channel)
return -ENODEV;
return sprintf(buf, "%d\n",
channel_latency(hv_dev->channel,
vmbus_connection.monitor_pages[0]));
}
static DEVICE_ATTR_RO(server_monitor_latency);
static ssize_t client_monitor_latency_show(struct device *dev,
struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
if (!hv_dev->channel)
return -ENODEV;
return sprintf(buf, "%d\n",
channel_latency(hv_dev->channel,
vmbus_connection.monitor_pages[1]));
}
static DEVICE_ATTR_RO(client_monitor_latency);
static ssize_t server_monitor_conn_id_show(struct device *dev,
struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
if (!hv_dev->channel)
return -ENODEV;
return sprintf(buf, "%d\n",
channel_conn_id(hv_dev->channel,
vmbus_connection.monitor_pages[0]));
}
static DEVICE_ATTR_RO(server_monitor_conn_id);
static ssize_t client_monitor_conn_id_show(struct device *dev,
struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
if (!hv_dev->channel)
return -ENODEV;
return sprintf(buf, "%d\n",
channel_conn_id(hv_dev->channel,
vmbus_connection.monitor_pages[1]));
}
static DEVICE_ATTR_RO(client_monitor_conn_id);
static ssize_t out_intr_mask_show(struct device *dev,
struct device_attribute *dev_attr, char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info outbound;
int ret;
if (!hv_dev->channel)
return -ENODEV;
ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
&outbound);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", outbound.current_interrupt_mask);
}
static DEVICE_ATTR_RO(out_intr_mask);
static ssize_t out_read_index_show(struct device *dev,
struct device_attribute *dev_attr, char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info outbound;
int ret;
if (!hv_dev->channel)
return -ENODEV;
ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
&outbound);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", outbound.current_read_index);
}
static DEVICE_ATTR_RO(out_read_index);
static ssize_t out_write_index_show(struct device *dev,
struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info outbound;
int ret;
if (!hv_dev->channel)
return -ENODEV;
ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
&outbound);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", outbound.current_write_index);
}
static DEVICE_ATTR_RO(out_write_index);
static ssize_t out_read_bytes_avail_show(struct device *dev,
struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info outbound;
int ret;
if (!hv_dev->channel)
return -ENODEV;
ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
&outbound);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", outbound.bytes_avail_toread);
}
static DEVICE_ATTR_RO(out_read_bytes_avail);
static ssize_t out_write_bytes_avail_show(struct device *dev,
struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info outbound;
int ret;
if (!hv_dev->channel)
return -ENODEV;
ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
&outbound);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", outbound.bytes_avail_towrite);
}
static DEVICE_ATTR_RO(out_write_bytes_avail);
static ssize_t in_intr_mask_show(struct device *dev,
struct device_attribute *dev_attr, char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info inbound;
int ret;
if (!hv_dev->channel)
return -ENODEV;
ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", inbound.current_interrupt_mask);
}
static DEVICE_ATTR_RO(in_intr_mask);
static ssize_t in_read_index_show(struct device *dev,
struct device_attribute *dev_attr, char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info inbound;
int ret;
if (!hv_dev->channel)
return -ENODEV;
ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", inbound.current_read_index);
}
static DEVICE_ATTR_RO(in_read_index);
static ssize_t in_write_index_show(struct device *dev,
struct device_attribute *dev_attr, char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info inbound;
int ret;
if (!hv_dev->channel)
return -ENODEV;
ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", inbound.current_write_index);
}
static DEVICE_ATTR_RO(in_write_index);
static ssize_t in_read_bytes_avail_show(struct device *dev,
struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info inbound;
int ret;
if (!hv_dev->channel)
return -ENODEV;
ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", inbound.bytes_avail_toread);
}
static DEVICE_ATTR_RO(in_read_bytes_avail);
static ssize_t in_write_bytes_avail_show(struct device *dev,
struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct hv_ring_buffer_debug_info inbound;
int ret;
if (!hv_dev->channel)
return -ENODEV;
ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", inbound.bytes_avail_towrite);
}
static DEVICE_ATTR_RO(in_write_bytes_avail);
static ssize_t channel_vp_mapping_show(struct device *dev,
struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
struct vmbus_channel *channel = hv_dev->channel, *cur_sc;
unsigned long flags;
int buf_size = PAGE_SIZE, n_written, tot_written;
struct list_head *cur;
if (!channel)
return -ENODEV;
tot_written = snprintf(buf, buf_size, "%u:%u\n",
channel->offermsg.child_relid, channel->target_cpu);
spin_lock_irqsave(&channel->lock, flags);
list_for_each(cur, &channel->sc_list) {
if (tot_written >= buf_size - 1)
break;
cur_sc = list_entry(cur, struct vmbus_channel, sc_list);
n_written = scnprintf(buf + tot_written,
buf_size - tot_written,
"%u:%u\n",
cur_sc->offermsg.child_relid,
cur_sc->target_cpu);
tot_written += n_written;
}
spin_unlock_irqrestore(&channel->lock, flags);
return tot_written;
}
static DEVICE_ATTR_RO(channel_vp_mapping);
static ssize_t vendor_show(struct device *dev,
struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
return sprintf(buf, "0x%x\n", hv_dev->vendor_id);
}
static DEVICE_ATTR_RO(vendor);
static ssize_t device_show(struct device *dev,
struct device_attribute *dev_attr,
char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
return sprintf(buf, "0x%x\n", hv_dev->device_id);
}
static DEVICE_ATTR_RO(device);
static ssize_t driver_override_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
char *driver_override, *old, *cp;
/* We need to keep extra room for a newline */
if (count >= (PAGE_SIZE - 1))
return -EINVAL;
driver_override = kstrndup(buf, count, GFP_KERNEL);
if (!driver_override)
return -ENOMEM;
cp = strchr(driver_override, '\n');
if (cp)
*cp = '\0';
device_lock(dev);
old = hv_dev->driver_override;
if (strlen(driver_override)) {
hv_dev->driver_override = driver_override;
} else {
kfree(driver_override);
hv_dev->driver_override = NULL;
}
device_unlock(dev);
kfree(old);
return count;
}
static ssize_t driver_override_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
ssize_t len;
device_lock(dev);
len = snprintf(buf, PAGE_SIZE, "%s\n", hv_dev->driver_override);
device_unlock(dev);
return len;
}
static DEVICE_ATTR_RW(driver_override);
/* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
static struct attribute *vmbus_dev_attrs[] = {
&dev_attr_id.attr,
&dev_attr_state.attr,
&dev_attr_monitor_id.attr,
&dev_attr_class_id.attr,
&dev_attr_device_id.attr,
&dev_attr_modalias.attr,
#ifdef CONFIG_NUMA
&dev_attr_numa_node.attr,
#endif
&dev_attr_server_monitor_pending.attr,
&dev_attr_client_monitor_pending.attr,
&dev_attr_server_monitor_latency.attr,
&dev_attr_client_monitor_latency.attr,
&dev_attr_server_monitor_conn_id.attr,
&dev_attr_client_monitor_conn_id.attr,
&dev_attr_out_intr_mask.attr,
&dev_attr_out_read_index.attr,
&dev_attr_out_write_index.attr,
&dev_attr_out_read_bytes_avail.attr,
&dev_attr_out_write_bytes_avail.attr,
&dev_attr_in_intr_mask.attr,
&dev_attr_in_read_index.attr,
&dev_attr_in_write_index.attr,
&dev_attr_in_read_bytes_avail.attr,
&dev_attr_in_write_bytes_avail.attr,
&dev_attr_channel_vp_mapping.attr,
&dev_attr_vendor.attr,
&dev_attr_device.attr,
&dev_attr_driver_override.attr,
NULL,
};
/*
* Device-level attribute_group callback function. Returns the permission for
* each attribute, and returns 0 if an attribute is not visible.
*/
static umode_t vmbus_dev_attr_is_visible(struct kobject *kobj,
struct attribute *attr, int idx)
{
struct device *dev = kobj_to_dev(kobj);
const struct hv_device *hv_dev = device_to_hv_device(dev);
/* Hide the monitor attributes if the monitor mechanism is not used. */
if (!hv_dev->channel->offermsg.monitor_allocated &&
(attr == &dev_attr_monitor_id.attr ||
attr == &dev_attr_server_monitor_pending.attr ||
attr == &dev_attr_client_monitor_pending.attr ||
attr == &dev_attr_server_monitor_latency.attr ||
attr == &dev_attr_client_monitor_latency.attr ||
attr == &dev_attr_server_monitor_conn_id.attr ||
attr == &dev_attr_client_monitor_conn_id.attr))
return 0;
return attr->mode;
}
static const struct attribute_group vmbus_dev_group = {
.attrs = vmbus_dev_attrs,
.is_visible = vmbus_dev_attr_is_visible
};
__ATTRIBUTE_GROUPS(vmbus_dev);
/*
* vmbus_uevent - add uevent for our device
*
* This routine is invoked when a device is added or removed on the vmbus to
* generate a uevent to udev in the userspace. The udev will then look at its
* rule and the uevent generated here to load the appropriate driver
*
* The alias string will be of the form vmbus:guid where guid is the string
* representation of the device guid (each byte of the guid will be
* represented with two hex characters.
*/
static int vmbus_uevent(struct device *device, struct kobj_uevent_env *env)
{
struct hv_device *dev = device_to_hv_device(device);
int ret;
char alias_name[VMBUS_ALIAS_LEN + 1];
print_alias_name(dev, alias_name);
ret = add_uevent_var(env, "MODALIAS=vmbus:%s", alias_name);
return ret;
}
static const struct hv_vmbus_device_id *
hv_vmbus_dev_match(const struct hv_vmbus_device_id *id, const guid_t *guid)
{
if (id == NULL)
return NULL; /* empty device table */
for (; !guid_is_null(&id->guid); id++)
if (guid_equal(&id->guid, guid))
return id;
return NULL;
}
static const struct hv_vmbus_device_id *
hv_vmbus_dynid_match(struct hv_driver *drv, const guid_t *guid)
{
const struct hv_vmbus_device_id *id = NULL;
struct vmbus_dynid *dynid;
spin_lock(&drv->dynids.lock);
list_for_each_entry(dynid, &drv->dynids.list, node) {
if (guid_equal(&dynid->id.guid, guid)) {
id = &dynid->id;
break;
}
}
spin_unlock(&drv->dynids.lock);
return id;
}
static const struct hv_vmbus_device_id vmbus_device_null;
/*
* Return a matching hv_vmbus_device_id pointer.
* If there is no match, return NULL.
*/
static const struct hv_vmbus_device_id *hv_vmbus_get_id(struct hv_driver *drv,
struct hv_device *dev)
{
const guid_t *guid = &dev->dev_type;
const struct hv_vmbus_device_id *id;
/* When driver_override is set, only bind to the matching driver */
if (dev->driver_override && strcmp(dev->driver_override, drv->name))
return NULL;
/* Look at the dynamic ids first, before the static ones */
id = hv_vmbus_dynid_match(drv, guid);
if (!id)
id = hv_vmbus_dev_match(drv->id_table, guid);
/* driver_override will always match, send a dummy id */
if (!id && dev->driver_override)
id = &vmbus_device_null;
return id;
}
/* vmbus_add_dynid - add a new device ID to this driver and re-probe devices */
static int vmbus_add_dynid(struct hv_driver *drv, guid_t *guid)
{
struct vmbus_dynid *dynid;
dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
if (!dynid)
return -ENOMEM;
dynid->id.guid = *guid;
spin_lock(&drv->dynids.lock);
list_add_tail(&dynid->node, &drv->dynids.list);
spin_unlock(&drv->dynids.lock);
return driver_attach(&drv->driver);
}
static void vmbus_free_dynids(struct hv_driver *drv)
{
struct vmbus_dynid *dynid, *n;
spin_lock(&drv->dynids.lock);
list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
list_del(&dynid->node);
kfree(dynid);
}
spin_unlock(&drv->dynids.lock);
}
/*
* store_new_id - sysfs frontend to vmbus_add_dynid()
*
* Allow GUIDs to be added to an existing driver via sysfs.
*/
static ssize_t new_id_store(struct device_driver *driver, const char *buf,
size_t count)
{
struct hv_driver *drv = drv_to_hv_drv(driver);
guid_t guid;
ssize_t retval;
retval = guid_parse(buf, &guid);
if (retval)
return retval;
if (hv_vmbus_dynid_match(drv, &guid))
return -EEXIST;
retval = vmbus_add_dynid(drv, &guid);
if (retval)
return retval;
return count;
}
static DRIVER_ATTR_WO(new_id);
/*
* store_remove_id - remove a PCI device ID from this driver
*
* Removes a dynamic pci device ID to this driver.
*/
static ssize_t remove_id_store(struct device_driver *driver, const char *buf,
size_t count)
{
struct hv_driver *drv = drv_to_hv_drv(driver);
struct vmbus_dynid *dynid, *n;
guid_t guid;
ssize_t retval;
retval = guid_parse(buf, &guid);
if (retval)
return retval;
retval = -ENODEV;
spin_lock(&drv->dynids.lock);
list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
struct hv_vmbus_device_id *id = &dynid->id;
if (guid_equal(&id->guid, &guid)) {
list_del(&dynid->node);
kfree(dynid);
retval = count;
break;
}
}
spin_unlock(&drv->dynids.lock);
return retval;
}
static DRIVER_ATTR_WO(remove_id);
static struct attribute *vmbus_drv_attrs[] = {
&driver_attr_new_id.attr,
&driver_attr_remove_id.attr,
NULL,
};
ATTRIBUTE_GROUPS(vmbus_drv);
/*
* vmbus_match - Attempt to match the specified device to the specified driver
*/
static int vmbus_match(struct device *device, struct device_driver *driver)
{
struct hv_driver *drv = drv_to_hv_drv(driver);
struct hv_device *hv_dev = device_to_hv_device(device);
/* The hv_sock driver handles all hv_sock offers. */
if (is_hvsock_channel(hv_dev->channel))
return drv->hvsock;
if (hv_vmbus_get_id(drv, hv_dev))
return 1;
return 0;
}
/*
* vmbus_probe - Add the new vmbus's child device
*/
static int vmbus_probe(struct device *child_device)
{
int ret = 0;
struct hv_driver *drv =
drv_to_hv_drv(child_device->driver);
struct hv_device *dev = device_to_hv_device(child_device);
const struct hv_vmbus_device_id *dev_id;
dev_id = hv_vmbus_get_id(drv, dev);
if (drv->probe) {
ret = drv->probe(dev, dev_id);
if (ret != 0)
pr_err("probe failed for device %s (%d)\n",
dev_name(child_device), ret);
} else {
pr_err("probe not set for driver %s\n",
dev_name(child_device));
ret = -ENODEV;
}
return ret;
}
/*
* vmbus_remove - Remove a vmbus device
*/
static int vmbus_remove(struct device *child_device)
{
struct hv_driver *drv;
struct hv_device *dev = device_to_hv_device(child_device);
if (child_device->driver) {
drv = drv_to_hv_drv(child_device->driver);
if (drv->remove)
drv->remove(dev);
}
return 0;
}
/*
* vmbus_shutdown - Shutdown a vmbus device
*/
static void vmbus_shutdown(struct device *child_device)
{
struct hv_driver *drv;
struct hv_device *dev = device_to_hv_device(child_device);
/* The device may not be attached yet */
if (!child_device->driver)
return;
drv = drv_to_hv_drv(child_device->driver);
if (drv->shutdown)
drv->shutdown(dev);
}
/*
* vmbus_device_release - Final callback release of the vmbus child device
*/
static void vmbus_device_release(struct device *device)
{
struct hv_device *hv_dev = device_to_hv_device(device);
struct vmbus_channel *channel = hv_dev->channel;
mutex_lock(&vmbus_connection.channel_mutex);
hv_process_channel_removal(channel);
mutex_unlock(&vmbus_connection.channel_mutex);
kfree(hv_dev);
}
/* The one and only one */
static struct bus_type hv_bus = {
.name = "vmbus",
.match = vmbus_match,
.shutdown = vmbus_shutdown,
.remove = vmbus_remove,
.probe = vmbus_probe,
.uevent = vmbus_uevent,
.dev_groups = vmbus_dev_groups,
.drv_groups = vmbus_drv_groups,
};
struct onmessage_work_context {
struct work_struct work;
struct hv_message msg;
};
static void vmbus_onmessage_work(struct work_struct *work)
{
struct onmessage_work_context *ctx;
/* Do not process messages if we're in DISCONNECTED state */
if (vmbus_connection.conn_state == DISCONNECTED)
return;
ctx = container_of(work, struct onmessage_work_context,
work);
vmbus_onmessage(&ctx->msg);
kfree(ctx);
}
static void hv_process_timer_expiration(struct hv_message *msg,
struct hv_per_cpu_context *hv_cpu)
{
struct clock_event_device *dev = hv_cpu->clk_evt;
if (dev->event_handler)
dev->event_handler(dev);
vmbus_signal_eom(msg, HVMSG_TIMER_EXPIRED);
}
void vmbus_on_msg_dpc(unsigned long data)
{
struct hv_per_cpu_context *hv_cpu = (void *)data;
void *page_addr = hv_cpu->synic_message_page;
struct hv_message *msg = (struct hv_message *)page_addr +
VMBUS_MESSAGE_SINT;
struct vmbus_channel_message_header *hdr;
const struct vmbus_channel_message_table_entry *entry;
struct onmessage_work_context *ctx;
u32 message_type = msg->header.message_type;
if (message_type == HVMSG_NONE)
/* no msg */
return;
hdr = (struct vmbus_channel_message_header *)msg->u.payload;
trace_vmbus_on_msg_dpc(hdr);
if (hdr->msgtype >= CHANNELMSG_COUNT) {
WARN_ONCE(1, "unknown msgtype=%d\n", hdr->msgtype);
goto msg_handled;
}
entry = &channel_message_table[hdr->msgtype];
if (entry->handler_type == VMHT_BLOCKING) {
ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
if (ctx == NULL)
return;
INIT_WORK(&ctx->work, vmbus_onmessage_work);
memcpy(&ctx->msg, msg, sizeof(*msg));
/*
* The host can generate a rescind message while we
* may still be handling the original offer. We deal with
* this condition by ensuring the processing is done on the
* same CPU.
*/
switch (hdr->msgtype) {
case CHANNELMSG_RESCIND_CHANNELOFFER:
/*
* If we are handling the rescind message;
* schedule the work on the global work queue.
*/
schedule_work_on(vmbus_connection.connect_cpu,
&ctx->work);
break;
case CHANNELMSG_OFFERCHANNEL:
atomic_inc(&vmbus_connection.offer_in_progress);
queue_work_on(vmbus_connection.connect_cpu,
vmbus_connection.work_queue,
&ctx->work);
break;
default:
queue_work(vmbus_connection.work_queue, &ctx->work);
}
} else
entry->message_handler(hdr);
msg_handled:
vmbus_signal_eom(msg, message_type);
}
/*
* Direct callback for channels using other deferred processing
*/
static void vmbus_channel_isr(struct vmbus_channel *channel)
{
void (*callback_fn)(void *);
callback_fn = READ_ONCE(channel->onchannel_callback);
if (likely(callback_fn != NULL))
(*callback_fn)(channel->channel_callback_context);
}
/*
* Schedule all channels with events pending
*/
static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu)
{
unsigned long *recv_int_page;
u32 maxbits, relid;
if (vmbus_proto_version < VERSION_WIN8) {
maxbits = MAX_NUM_CHANNELS_SUPPORTED;
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.
*/
void *page_addr = hv_cpu->synic_event_page;
union hv_synic_event_flags *event
= (union hv_synic_event_flags *)page_addr +
VMBUS_MESSAGE_SINT;
maxbits = HV_EVENT_FLAGS_COUNT;
recv_int_page = event->flags;
}
if (unlikely(!recv_int_page))
return;
for_each_set_bit(relid, recv_int_page, maxbits) {
struct vmbus_channel *channel;
if (!sync_test_and_clear_bit(relid, recv_int_page))
continue;
/* Special case - vmbus channel protocol msg */
if (relid == 0)
continue;
rcu_read_lock();
/* Find channel based on relid */
list_for_each_entry_rcu(channel, &hv_cpu->chan_list, percpu_list) {
if (channel->offermsg.child_relid != relid)
continue;
if (channel->rescind)
continue;
trace_vmbus_chan_sched(channel);
++channel->interrupts;
switch (channel->callback_mode) {
case HV_CALL_ISR:
vmbus_channel_isr(channel);
break;
case HV_CALL_BATCHED:
hv_begin_read(&channel->inbound);
/* fallthrough */
case HV_CALL_DIRECT:
tasklet_schedule(&channel->callback_event);
}
}
rcu_read_unlock();
}
}
static void vmbus_isr(void)
{
struct hv_per_cpu_context *hv_cpu
= this_cpu_ptr(hv_context.cpu_context);
void *page_addr = hv_cpu->synic_event_page;
struct hv_message *msg;
union hv_synic_event_flags *event;
bool handled = false;
if (unlikely(page_addr == NULL))
return;
event = (union hv_synic_event_flags *)page_addr +
VMBUS_MESSAGE_SINT;
/*
* Check for events before checking for messages. This is the order
* in which events and messages are checked in Windows guests on
* Hyper-V, and the Windows team suggested we do the same.
*/
if ((vmbus_proto_version == VERSION_WS2008) ||
(vmbus_proto_version == VERSION_WIN7)) {
/* Since we are a child, we only need to check bit 0 */
if (sync_test_and_clear_bit(0, event->flags))
handled = true;
} else {
/*
* Our host is win8 or above. The signaling mechanism
* has changed and we can directly look at the event page.
* If bit n is set then we have an interrup on the channel
* whose id is n.
*/
handled = true;
}
if (handled)
vmbus_chan_sched(hv_cpu);
page_addr = hv_cpu->synic_message_page;
msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
/* Check if there are actual msgs to be processed */
if (msg->header.message_type != HVMSG_NONE) {
if (msg->header.message_type == HVMSG_TIMER_EXPIRED)
hv_process_timer_expiration(msg, hv_cpu);
else
tasklet_schedule(&hv_cpu->msg_dpc);
}
add_interrupt_randomness(HYPERVISOR_CALLBACK_VECTOR, 0);
}
/*
* Boolean to control whether to report panic messages over Hyper-V.
*
* It can be set via /proc/sys/kernel/hyperv/record_panic_msg
*/
static int sysctl_record_panic_msg = 1;
/*
* Callback from kmsg_dump. Grab as much as possible from the end of the kmsg
* buffer and call into Hyper-V to transfer the data.
*/
static void hv_kmsg_dump(struct kmsg_dumper *dumper,
enum kmsg_dump_reason reason)
{
size_t bytes_written;
phys_addr_t panic_pa;
/* We are only interested in panics. */
if ((reason != KMSG_DUMP_PANIC) || (!sysctl_record_panic_msg))
return;
panic_pa = virt_to_phys(hv_panic_page);
/*
* Write dump contents to the page. No need to synchronize; panic should
* be single-threaded.
*/
kmsg_dump_get_buffer(dumper, true, hv_panic_page, PAGE_SIZE,
&bytes_written);
if (bytes_written)
hyperv_report_panic_msg(panic_pa, bytes_written);
}
static struct kmsg_dumper hv_kmsg_dumper = {
.dump = hv_kmsg_dump,
};
static struct ctl_table_header *hv_ctl_table_hdr;
static int zero;
static int one = 1;
/*
* sysctl option to allow the user to control whether kmsg data should be
* reported to Hyper-V on panic.
*/
static struct ctl_table hv_ctl_table[] = {
{
.procname = "hyperv_record_panic_msg",
.data = &sysctl_record_panic_msg,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
.extra2 = &one
},
{}
};
static struct ctl_table hv_root_table[] = {
{
.procname = "kernel",
.mode = 0555,
.child = hv_ctl_table
},
{}
};
/*
* vmbus_bus_init -Main vmbus driver initialization routine.
*
* Here, we
* - initialize the vmbus driver context
* - invoke the vmbus hv main init routine
* - retrieve the channel offers
*/
static int vmbus_bus_init(void)
{
int ret;
/* Hypervisor initialization...setup hypercall page..etc */
ret = hv_init();
if (ret != 0) {
pr_err("Unable to initialize the hypervisor - 0x%x\n", ret);
return ret;
}
ret = bus_register(&hv_bus);
if (ret)
return ret;
hv_setup_vmbus_irq(vmbus_isr);
ret = hv_synic_alloc();
if (ret)
goto err_alloc;
/*
* Initialize the per-cpu interrupt state and
* connect to the host.
*/
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hyperv/vmbus:online",
hv_synic_init, hv_synic_cleanup);
if (ret < 0)
goto err_alloc;
hyperv_cpuhp_online = ret;
ret = vmbus_connect();
if (ret)
goto err_connect;
/*
* Only register if the crash MSRs are available
*/
if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
u64 hyperv_crash_ctl;
/*
* Sysctl registration is not fatal, since by default
* reporting is enabled.
*/
hv_ctl_table_hdr = register_sysctl_table(hv_root_table);
if (!hv_ctl_table_hdr)
pr_err("Hyper-V: sysctl table register error");
/*
* Register for panic kmsg callback only if the right
* capability is supported by the hypervisor.
*/
hv_get_crash_ctl(hyperv_crash_ctl);
if (hyperv_crash_ctl & HV_CRASH_CTL_CRASH_NOTIFY_MSG) {
hv_panic_page = (void *)get_zeroed_page(GFP_KERNEL);
if (hv_panic_page) {
ret = kmsg_dump_register(&hv_kmsg_dumper);
if (ret)
pr_err("Hyper-V: kmsg dump register "
"error 0x%x\n", ret);
} else
pr_err("Hyper-V: panic message page memory "
"allocation failed");
}
register_die_notifier(&hyperv_die_block);
atomic_notifier_chain_register(&panic_notifier_list,
&hyperv_panic_block);
}
vmbus_request_offers();
return 0;
err_connect:
cpuhp_remove_state(hyperv_cpuhp_online);
err_alloc:
hv_synic_free();
hv_remove_vmbus_irq();
bus_unregister(&hv_bus);
free_page((unsigned long)hv_panic_page);
unregister_sysctl_table(hv_ctl_table_hdr);
hv_ctl_table_hdr = NULL;
return ret;
}
/**
* __vmbus_child_driver_register() - Register a vmbus's driver
* @hv_driver: Pointer to driver structure you want to register
* @owner: owner module of the drv
* @mod_name: module name string
*
* Registers the given driver with Linux through the 'driver_register()' call
* and sets up the hyper-v vmbus handling for this driver.
* It will return the state of the 'driver_register()' call.
*
*/
int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, const char *mod_name)
{
int ret;
pr_info("registering driver %s\n", hv_driver->name);
ret = vmbus_exists();
if (ret < 0)
return ret;
hv_driver->driver.name = hv_driver->name;
hv_driver->driver.owner = owner;
hv_driver->driver.mod_name = mod_name;
hv_driver->driver.bus = &hv_bus;
spin_lock_init(&hv_driver->dynids.lock);
INIT_LIST_HEAD(&hv_driver->dynids.list);
ret = driver_register(&hv_driver->driver);
return ret;
}
EXPORT_SYMBOL_GPL(__vmbus_driver_register);
/**
* vmbus_driver_unregister() - Unregister a vmbus's driver
* @hv_driver: Pointer to driver structure you want to
* un-register
*
* Un-register the given driver that was previous registered with a call to
* vmbus_driver_register()
*/
void vmbus_driver_unregister(struct hv_driver *hv_driver)
{
pr_info("unregistering driver %s\n", hv_driver->name);
if (!vmbus_exists()) {
driver_unregister(&hv_driver->driver);
vmbus_free_dynids(hv_driver);
}
}
EXPORT_SYMBOL_GPL(vmbus_driver_unregister);
/*
* Called when last reference to channel is gone.
*/
static void vmbus_chan_release(struct kobject *kobj)
{
struct vmbus_channel *channel
= container_of(kobj, struct vmbus_channel, kobj);
kfree_rcu(channel, rcu);
}
struct vmbus_chan_attribute {
struct attribute attr;
ssize_t (*show)(struct vmbus_channel *chan, char *buf);
ssize_t (*store)(struct vmbus_channel *chan,
const char *buf, size_t count);
};
#define VMBUS_CHAN_ATTR(_name, _mode, _show, _store) \
struct vmbus_chan_attribute chan_attr_##_name \
= __ATTR(_name, _mode, _show, _store)
#define VMBUS_CHAN_ATTR_RW(_name) \
struct vmbus_chan_attribute chan_attr_##_name = __ATTR_RW(_name)
#define VMBUS_CHAN_ATTR_RO(_name) \
struct vmbus_chan_attribute chan_attr_##_name = __ATTR_RO(_name)
#define VMBUS_CHAN_ATTR_WO(_name) \
struct vmbus_chan_attribute chan_attr_##_name = __ATTR_WO(_name)
static ssize_t vmbus_chan_attr_show(struct kobject *kobj,
struct attribute *attr, char *buf)
{
const struct vmbus_chan_attribute *attribute
= container_of(attr, struct vmbus_chan_attribute, attr);
struct vmbus_channel *chan
= container_of(kobj, struct vmbus_channel, kobj);
if (!attribute->show)
return -EIO;
return attribute->show(chan, buf);
}
static const struct sysfs_ops vmbus_chan_sysfs_ops = {
.show = vmbus_chan_attr_show,
};
static ssize_t out_mask_show(struct vmbus_channel *channel, char *buf)
{
struct hv_ring_buffer_info *rbi = &channel->outbound;
ssize_t ret;
mutex_lock(&rbi->ring_buffer_mutex);
if (!rbi->ring_buffer) {
mutex_unlock(&rbi->ring_buffer_mutex);
return -EINVAL;
}
ret = sprintf(buf, "%u\n", rbi->ring_buffer->interrupt_mask);
mutex_unlock(&rbi->ring_buffer_mutex);
return ret;
}
static VMBUS_CHAN_ATTR_RO(out_mask);
static ssize_t in_mask_show(struct vmbus_channel *channel, char *buf)
{
struct hv_ring_buffer_info *rbi = &channel->inbound;
ssize_t ret;
mutex_lock(&rbi->ring_buffer_mutex);
if (!rbi->ring_buffer) {
mutex_unlock(&rbi->ring_buffer_mutex);
return -EINVAL;
}
ret = sprintf(buf, "%u\n", rbi->ring_buffer->interrupt_mask);
mutex_unlock(&rbi->ring_buffer_mutex);
return ret;
}
static VMBUS_CHAN_ATTR_RO(in_mask);
static ssize_t read_avail_show(struct vmbus_channel *channel, char *buf)
{
struct hv_ring_buffer_info *rbi = &channel->inbound;
ssize_t ret;
mutex_lock(&rbi->ring_buffer_mutex);
if (!rbi->ring_buffer) {
mutex_unlock(&rbi->ring_buffer_mutex);
return -EINVAL;
}
ret = sprintf(buf, "%u\n", hv_get_bytes_to_read(rbi));
mutex_unlock(&rbi->ring_buffer_mutex);
return ret;
}
static VMBUS_CHAN_ATTR_RO(read_avail);
static ssize_t write_avail_show(struct vmbus_channel *channel, char *buf)
{
struct hv_ring_buffer_info *rbi = &channel->outbound;
ssize_t ret;
mutex_lock(&rbi->ring_buffer_mutex);
if (!rbi->ring_buffer) {
mutex_unlock(&rbi->ring_buffer_mutex);
return -EINVAL;
}
ret = sprintf(buf, "%u\n", hv_get_bytes_to_write(rbi));
mutex_unlock(&rbi->ring_buffer_mutex);
return ret;
}
static VMBUS_CHAN_ATTR_RO(write_avail);
static ssize_t show_target_cpu(struct vmbus_channel *channel, char *buf)
{
return sprintf(buf, "%u\n", channel->target_cpu);
}
static VMBUS_CHAN_ATTR(cpu, S_IRUGO, show_target_cpu, NULL);
static ssize_t channel_pending_show(struct vmbus_channel *channel,
char *buf)
{
return sprintf(buf, "%d\n",
channel_pending(channel,
vmbus_connection.monitor_pages[1]));
}
static VMBUS_CHAN_ATTR(pending, S_IRUGO, channel_pending_show, NULL);
static ssize_t channel_latency_show(struct vmbus_channel *channel,
char *buf)
{
return sprintf(buf, "%d\n",
channel_latency(channel,
vmbus_connection.monitor_pages[1]));
}
static VMBUS_CHAN_ATTR(latency, S_IRUGO, channel_latency_show, NULL);
static ssize_t channel_interrupts_show(struct vmbus_channel *channel, char *buf)
{
return sprintf(buf, "%llu\n", channel->interrupts);
}
static VMBUS_CHAN_ATTR(interrupts, S_IRUGO, channel_interrupts_show, NULL);
static ssize_t channel_events_show(struct vmbus_channel *channel, char *buf)
{
return sprintf(buf, "%llu\n", channel->sig_events);
}
static VMBUS_CHAN_ATTR(events, S_IRUGO, channel_events_show, NULL);
static ssize_t channel_intr_in_full_show(struct vmbus_channel *channel,
char *buf)
{
return sprintf(buf, "%llu\n",
(unsigned long long)channel->intr_in_full);
}
static VMBUS_CHAN_ATTR(intr_in_full, 0444, channel_intr_in_full_show, NULL);
static ssize_t channel_intr_out_empty_show(struct vmbus_channel *channel,
char *buf)
{
return sprintf(buf, "%llu\n",
(unsigned long long)channel->intr_out_empty);
}
static VMBUS_CHAN_ATTR(intr_out_empty, 0444, channel_intr_out_empty_show, NULL);
static ssize_t channel_out_full_first_show(struct vmbus_channel *channel,
char *buf)
{
return sprintf(buf, "%llu\n",
(unsigned long long)channel->out_full_first);
}
static VMBUS_CHAN_ATTR(out_full_first, 0444, channel_out_full_first_show, NULL);
static ssize_t channel_out_full_total_show(struct vmbus_channel *channel,
char *buf)
{
return sprintf(buf, "%llu\n",
(unsigned long long)channel->out_full_total);
}
static VMBUS_CHAN_ATTR(out_full_total, 0444, channel_out_full_total_show, NULL);
static ssize_t subchannel_monitor_id_show(struct vmbus_channel *channel,
char *buf)
{
return sprintf(buf, "%u\n", channel->offermsg.monitorid);
}
static VMBUS_CHAN_ATTR(monitor_id, S_IRUGO, subchannel_monitor_id_show, NULL);
static ssize_t subchannel_id_show(struct vmbus_channel *channel,
char *buf)
{
return sprintf(buf, "%u\n",
channel->offermsg.offer.sub_channel_index);
}
static VMBUS_CHAN_ATTR_RO(subchannel_id);
static struct attribute *vmbus_chan_attrs[] = {
&chan_attr_out_mask.attr,
&chan_attr_in_mask.attr,
&chan_attr_read_avail.attr,
&chan_attr_write_avail.attr,
&chan_attr_cpu.attr,
&chan_attr_pending.attr,
&chan_attr_latency.attr,
&chan_attr_interrupts.attr,
&chan_attr_events.attr,
&chan_attr_intr_in_full.attr,
&chan_attr_intr_out_empty.attr,
&chan_attr_out_full_first.attr,
&chan_attr_out_full_total.attr,
&chan_attr_monitor_id.attr,
&chan_attr_subchannel_id.attr,
NULL
};
/*
* Channel-level attribute_group callback function. Returns the permission for
* each attribute, and returns 0 if an attribute is not visible.
*/
static umode_t vmbus_chan_attr_is_visible(struct kobject *kobj,
struct attribute *attr, int idx)
{
const struct vmbus_channel *channel =
container_of(kobj, struct vmbus_channel, kobj);
/* Hide the monitor attributes if the monitor mechanism is not used. */
if (!channel->offermsg.monitor_allocated &&
(attr == &chan_attr_pending.attr ||
attr == &chan_attr_latency.attr ||
attr == &chan_attr_monitor_id.attr))
return 0;
return attr->mode;
}
static struct attribute_group vmbus_chan_group = {
.attrs = vmbus_chan_attrs,
.is_visible = vmbus_chan_attr_is_visible
};
static struct kobj_type vmbus_chan_ktype = {
.sysfs_ops = &vmbus_chan_sysfs_ops,
.release = vmbus_chan_release,
};
/*
* vmbus_add_channel_kobj - setup a sub-directory under device/channels
*/
int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
{
const struct device *device = &dev->device;
struct kobject *kobj = &channel->kobj;
u32 relid = channel->offermsg.child_relid;
int ret;
kobj->kset = dev->channels_kset;
ret = kobject_init_and_add(kobj, &vmbus_chan_ktype, NULL,
"%u", relid);
if (ret)
return ret;
ret = sysfs_create_group(kobj, &vmbus_chan_group);
if (ret) {
/*
* The calling functions' error handling paths will cleanup the
* empty channel directory.
*/
dev_err(device, "Unable to set up channel sysfs files\n");
return ret;
}
kobject_uevent(kobj, KOBJ_ADD);
return 0;
}
/*
* vmbus_remove_channel_attr_group - remove the channel's attribute group
*/
void vmbus_remove_channel_attr_group(struct vmbus_channel *channel)
{
sysfs_remove_group(&channel->kobj, &vmbus_chan_group);
}
/*
* vmbus_device_create - Creates and registers a new child device
* on the vmbus.
*/
struct hv_device *vmbus_device_create(const guid_t *type,
const guid_t *instance,
struct vmbus_channel *channel)
{
struct hv_device *child_device_obj;
child_device_obj = kzalloc(sizeof(struct hv_device), GFP_KERNEL);
if (!child_device_obj) {
pr_err("Unable to allocate device object for child device\n");
return NULL;
}
child_device_obj->channel = channel;
guid_copy(&child_device_obj->dev_type, type);
guid_copy(&child_device_obj->dev_instance, instance);
child_device_obj->vendor_id = 0x1414; /* MSFT vendor ID */
return child_device_obj;
}
/*
* vmbus_device_register - Register the child device
*/
int vmbus_device_register(struct hv_device *child_device_obj)
{
struct kobject *kobj = &child_device_obj->device.kobj;
int ret;
dev_set_name(&child_device_obj->device, "%pUl",
child_device_obj->channel->offermsg.offer.if_instance.b);
child_device_obj->device.bus = &hv_bus;
child_device_obj->device.parent = &hv_acpi_dev->dev;
child_device_obj->device.release = vmbus_device_release;
/*
* Register with the LDM. This will kick off the driver/device
* binding...which will eventually call vmbus_match() and vmbus_probe()
*/
ret = device_register(&child_device_obj->device);
if (ret) {
pr_err("Unable to register child device\n");
return ret;
}
child_device_obj->channels_kset = kset_create_and_add("channels",
NULL, kobj);
if (!child_device_obj->channels_kset) {
ret = -ENOMEM;
goto err_dev_unregister;
}
ret = vmbus_add_channel_kobj(child_device_obj,
child_device_obj->channel);
if (ret) {
pr_err("Unable to register primary channeln");
goto err_kset_unregister;
}
return 0;
err_kset_unregister:
kset_unregister(child_device_obj->channels_kset);
err_dev_unregister:
device_unregister(&child_device_obj->device);
return ret;
}
/*
* vmbus_device_unregister - Remove the specified child device
* from the vmbus.
*/
void vmbus_device_unregister(struct hv_device *device_obj)
{
pr_debug("child device %s unregistered\n",
dev_name(&device_obj->device));
kset_unregister(device_obj->channels_kset);
/*
* Kick off the process of unregistering the device.
* This will call vmbus_remove() and eventually vmbus_device_release()
*/
device_unregister(&device_obj->device);
}
/*
* VMBUS is an acpi enumerated device. Get the information we
* need from DSDT.
*/
#define VTPM_BASE_ADDRESS 0xfed40000
static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
{
resource_size_t start = 0;
resource_size_t end = 0;
struct resource *new_res;
struct resource **old_res = &hyperv_mmio;
struct resource **prev_res = NULL;
switch (res->type) {
/*
* "Address" descriptors are for bus windows. Ignore
* "memory" descriptors, which are for registers on
* devices.
*/
case ACPI_RESOURCE_TYPE_ADDRESS32:
start = res->data.address32.address.minimum;
end = res->data.address32.address.maximum;
break;
case ACPI_RESOURCE_TYPE_ADDRESS64:
start = res->data.address64.address.minimum;
end = res->data.address64.address.maximum;
break;
default:
/* Unused resource type */
return AE_OK;
}
/*
* Ignore ranges that are below 1MB, as they're not
* necessary or useful here.
*/
if (end < 0x100000)
return AE_OK;
new_res = kzalloc(sizeof(*new_res), GFP_ATOMIC);
if (!new_res)
return AE_NO_MEMORY;
/* If this range overlaps the virtual TPM, truncate it. */
if (end > VTPM_BASE_ADDRESS && start < VTPM_BASE_ADDRESS)
end = VTPM_BASE_ADDRESS;
new_res->name = "hyperv mmio";
new_res->flags = IORESOURCE_MEM;
new_res->start = start;
new_res->end = end;
/*
* If two ranges are adjacent, merge them.
*/
do {
if (!*old_res) {
*old_res = new_res;
break;
}
if (((*old_res)->end + 1) == new_res->start) {
(*old_res)->end = new_res->end;
kfree(new_res);
break;
}
if ((*old_res)->start == new_res->end + 1) {
(*old_res)->start = new_res->start;
kfree(new_res);
break;
}
if ((*old_res)->start > new_res->end) {
new_res->sibling = *old_res;
if (prev_res)
(*prev_res)->sibling = new_res;
*old_res = new_res;
break;
}
prev_res = old_res;
old_res = &(*old_res)->sibling;
} while (1);
return AE_OK;
}
static int vmbus_acpi_remove(struct acpi_device *device)
{
struct resource *cur_res;
struct resource *next_res;
if (hyperv_mmio) {
if (fb_mmio) {
__release_region(hyperv_mmio, fb_mmio->start,
resource_size(fb_mmio));
fb_mmio = NULL;
}
for (cur_res = hyperv_mmio; cur_res; cur_res = next_res) {
next_res = cur_res->sibling;
kfree(cur_res);
}
}
return 0;
}
static void vmbus_reserve_fb(void)
{
int size;
/*
* Make a claim for the frame buffer in the resource tree under the
* first node, which will be the one below 4GB. The length seems to
* be underreported, particularly in a Generation 1 VM. So start out
* reserving a larger area and make it smaller until it succeeds.
*/
if (screen_info.lfb_base) {
if (efi_enabled(EFI_BOOT))
size = max_t(__u32, screen_info.lfb_size, 0x800000);
else
size = max_t(__u32, screen_info.lfb_size, 0x4000000);
for (; !fb_mmio && (size >= 0x100000); size >>= 1) {
fb_mmio = __request_region(hyperv_mmio,
screen_info.lfb_base, size,
fb_mmio_name, 0);
}
}
}
/**
* vmbus_allocate_mmio() - Pick a memory-mapped I/O range.
* @new: If successful, supplied a pointer to the
* allocated MMIO space.
* @device_obj: Identifies the caller
* @min: Minimum guest physical address of the
* allocation
* @max: Maximum guest physical address
* @size: Size of the range to be allocated
* @align: Alignment of the range to be allocated
* @fb_overlap_ok: Whether this allocation can be allowed
* to overlap the video frame buffer.
*
* This function walks the resources granted to VMBus by the
* _CRS object in the ACPI namespace underneath the parent
* "bridge" whether that's a root PCI bus in the Generation 1
* case or a Module Device in the Generation 2 case. It then
* attempts to allocate from the global MMIO pool in a way that
* matches the constraints supplied in these parameters and by
* that _CRS.
*
* Return: 0 on success, -errno on failure
*/
int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
resource_size_t min, resource_size_t max,
resource_size_t size, resource_size_t align,
bool fb_overlap_ok)
{
struct resource *iter, *shadow;
resource_size_t range_min, range_max, start;
const char *dev_n = dev_name(&device_obj->device);
int retval;
retval = -ENXIO;
down(&hyperv_mmio_lock);
/*
* If overlaps with frame buffers are allowed, then first attempt to
* make the allocation from within the reserved region. Because it
* is already reserved, no shadow allocation is necessary.
*/
if (fb_overlap_ok && fb_mmio && !(min > fb_mmio->end) &&
!(max < fb_mmio->start)) {
range_min = fb_mmio->start;
range_max = fb_mmio->end;
start = (range_min + align - 1) & ~(align - 1);
for (; start + size - 1 <= range_max; start += align) {
*new = request_mem_region_exclusive(start, size, dev_n);
if (*new) {
retval = 0;
goto exit;
}
}
}
for (iter = hyperv_mmio; iter; iter = iter->sibling) {
if ((iter->start >= max) || (iter->end <= min))
continue;
range_min = iter->start;
range_max = iter->end;
start = (range_min + align - 1) & ~(align - 1);
for (; start + size - 1 <= range_max; start += align) {
shadow = __request_region(iter, start, size, NULL,
IORESOURCE_BUSY);
if (!shadow)
continue;
*new = request_mem_region_exclusive(start, size, dev_n);
if (*new) {
shadow->name = (char *)*new;
retval = 0;
goto exit;
}
__release_region(iter, start, size);
}
}
exit:
up(&hyperv_mmio_lock);
return retval;
}
EXPORT_SYMBOL_GPL(vmbus_allocate_mmio);
/**
* vmbus_free_mmio() - Free a memory-mapped I/O range.
* @start: Base address of region to release.
* @size: Size of the range to be allocated
*
* This function releases anything requested by
* vmbus_mmio_allocate().
*/
void vmbus_free_mmio(resource_size_t start, resource_size_t size)
{
struct resource *iter;
down(&hyperv_mmio_lock);
for (iter = hyperv_mmio; iter; iter = iter->sibling) {
if ((iter->start >= start + size) || (iter->end <= start))
continue;
__release_region(iter, start, size);
}
release_mem_region(start, size);
up(&hyperv_mmio_lock);
}
EXPORT_SYMBOL_GPL(vmbus_free_mmio);
static int vmbus_acpi_add(struct acpi_device *device)
{
acpi_status result;
int ret_val = -ENODEV;
struct acpi_device *ancestor;
hv_acpi_dev = device;
result = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
vmbus_walk_resources, NULL);
if (ACPI_FAILURE(result))
goto acpi_walk_err;
/*
* Some ancestor of the vmbus acpi device (Gen1 or Gen2
* firmware) is the VMOD that has the mmio ranges. Get that.
*/
for (ancestor = device->parent; ancestor; ancestor = ancestor->parent) {
result = acpi_walk_resources(ancestor->handle, METHOD_NAME__CRS,
vmbus_walk_resources, NULL);
if (ACPI_FAILURE(result))
continue;
if (hyperv_mmio) {
vmbus_reserve_fb();
break;
}
}
ret_val = 0;
acpi_walk_err:
complete(&probe_event);
if (ret_val)
vmbus_acpi_remove(device);
return ret_val;
}
static const struct acpi_device_id vmbus_acpi_device_ids[] = {
{"VMBUS", 0},
{"VMBus", 0},
{"", 0},
};
MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
static struct acpi_driver vmbus_acpi_driver = {
.name = "vmbus",
.ids = vmbus_acpi_device_ids,
.ops = {
.add = vmbus_acpi_add,
.remove = vmbus_acpi_remove,
},
};
static void hv_kexec_handler(void)
{
hv_synic_clockevents_cleanup();
vmbus_initiate_unload(false);
vmbus_connection.conn_state = DISCONNECTED;
/* Make sure conn_state is set as hv_synic_cleanup checks for it */
mb();
cpuhp_remove_state(hyperv_cpuhp_online);
hyperv_cleanup();
};
static void hv_crash_handler(struct pt_regs *regs)
{
vmbus_initiate_unload(true);
/*
* In crash handler we can't schedule synic cleanup for all CPUs,
* doing the cleanup for current CPU only. This should be sufficient
* for kdump.
*/
vmbus_connection.conn_state = DISCONNECTED;
hv_synic_cleanup(smp_processor_id());
hyperv_cleanup();
};
static int __init hv_acpi_init(void)
{
int ret, t;
if (!hv_is_hyperv_initialized())
return -ENODEV;
init_completion(&probe_event);
/*
* Get ACPI resources first.
*/
ret = acpi_bus_register_driver(&vmbus_acpi_driver);
if (ret)
return ret;
t = wait_for_completion_timeout(&probe_event, 5*HZ);
if (t == 0) {
ret = -ETIMEDOUT;
goto cleanup;
}
ret = vmbus_bus_init();
if (ret)
goto cleanup;
hv_setup_kexec_handler(hv_kexec_handler);
hv_setup_crash_handler(hv_crash_handler);
return 0;
cleanup:
acpi_bus_unregister_driver(&vmbus_acpi_driver);
hv_acpi_dev = NULL;
return ret;
}
static void __exit vmbus_exit(void)
{
int cpu;
hv_remove_kexec_handler();
hv_remove_crash_handler();
vmbus_connection.conn_state = DISCONNECTED;
hv_synic_clockevents_cleanup();
vmbus_disconnect();
hv_remove_vmbus_irq();
for_each_online_cpu(cpu) {
struct hv_per_cpu_context *hv_cpu
= per_cpu_ptr(hv_context.cpu_context, cpu);
tasklet_kill(&hv_cpu->msg_dpc);
}
vmbus_free_channels();
if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
kmsg_dump_unregister(&hv_kmsg_dumper);
unregister_die_notifier(&hyperv_die_block);
atomic_notifier_chain_unregister(&panic_notifier_list,
&hyperv_panic_block);
}
free_page((unsigned long)hv_panic_page);
unregister_sysctl_table(hv_ctl_table_hdr);
hv_ctl_table_hdr = NULL;
bus_unregister(&hv_bus);
cpuhp_remove_state(hyperv_cpuhp_online);
hv_synic_free();
acpi_bus_unregister_driver(&vmbus_acpi_driver);
}
MODULE_LICENSE("GPL");
subsys_initcall(hv_acpi_init);
module_exit(vmbus_exit);
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