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-rw-r--r--kernel/drivers/hv/vmbus_drv.c1114
1 files changed, 1114 insertions, 0 deletions
diff --git a/kernel/drivers/hv/vmbus_drv.c b/kernel/drivers/hv/vmbus_drv.c
new file mode 100644
index 000000000..c85235e9f
--- /dev/null
+++ b/kernel/drivers/hv/vmbus_drv.c
@@ -0,0 +1,1114 @@
+/*
+ * 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 <asm/hyperv.h>
+#include <asm/hypervisor.h>
+#include <asm/mshyperv.h>
+#include <linux/notifier.h>
+#include <linux/ptrace.h>
+#include "hyperv_vmbus.h"
+
+static struct acpi_device *hv_acpi_dev;
+
+static struct tasklet_struct msg_dpc;
+static struct completion probe_event;
+static int irq;
+
+
+static int hyperv_panic_event(struct notifier_block *nb,
+ unsigned long event, void *ptr)
+{
+ struct pt_regs *regs;
+
+ regs = current_pt_regs();
+
+ wrmsrl(HV_X64_MSR_CRASH_P0, regs->ip);
+ wrmsrl(HV_X64_MSR_CRASH_P1, regs->ax);
+ wrmsrl(HV_X64_MSR_CRASH_P2, regs->bx);
+ wrmsrl(HV_X64_MSR_CRASH_P3, regs->cx);
+ wrmsrl(HV_X64_MSR_CRASH_P4, regs->dx);
+
+ /*
+ * Let Hyper-V know there is crash data available
+ */
+ wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block hyperv_panic_block = {
+ .notifier_call = hyperv_panic_event,
+};
+
+struct resource hyperv_mmio = {
+ .name = "hyperv mmio",
+ .flags = IORESOURCE_MEM,
+};
+EXPORT_SYMBOL_GPL(hyperv_mmio);
+
+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(struct vmbus_channel *channel)
+{
+ return (u8)channel->offermsg.monitorid / 32;
+}
+
+static u8 channel_monitor_offset(struct vmbus_channel *channel)
+{
+ return (u8)channel->offermsg.monitorid % 32;
+}
+
+static u32 channel_pending(struct vmbus_channel *channel,
+ 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(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->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);
+
+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[1]));
+}
+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;
+
+ if (!hv_dev->channel)
+ return -ENODEV;
+ hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
+ 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;
+
+ if (!hv_dev->channel)
+ return -ENODEV;
+ hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
+ 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;
+
+ if (!hv_dev->channel)
+ return -ENODEV;
+ hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
+ 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;
+
+ if (!hv_dev->channel)
+ return -ENODEV;
+ hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
+ 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;
+
+ if (!hv_dev->channel)
+ return -ENODEV;
+ hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
+ 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;
+
+ if (!hv_dev->channel)
+ return -ENODEV;
+ hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+ 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;
+
+ if (!hv_dev->channel)
+ return -ENODEV;
+ hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+ 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;
+
+ if (!hv_dev->channel)
+ return -ENODEV;
+ hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+ 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;
+
+ if (!hv_dev->channel)
+ return -ENODEV;
+ hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+ 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;
+
+ if (!hv_dev->channel)
+ return -ENODEV;
+ hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+ return sprintf(buf, "%d\n", inbound.bytes_avail_towrite);
+}
+static DEVICE_ATTR_RO(in_write_bytes_avail);
+
+/* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
+static struct attribute *vmbus_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,
+ &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,
+ NULL,
+};
+ATTRIBUTE_GROUPS(vmbus);
+
+/*
+ * 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 uuid_le null_guid;
+
+static inline bool is_null_guid(const __u8 *guid)
+{
+ if (memcmp(guid, &null_guid, sizeof(uuid_le)))
+ return false;
+ return true;
+}
+
+/*
+ * 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(
+ const struct hv_vmbus_device_id *id,
+ const __u8 *guid)
+{
+ for (; !is_null_guid(id->guid); id++)
+ if (!memcmp(&id->guid, guid, sizeof(uuid_le)))
+ return id;
+
+ return NULL;
+}
+
+
+
+/*
+ * 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);
+
+ if (hv_vmbus_get_id(drv->id_table, hv_dev->dev_type.b))
+ 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->id_table, dev->dev_type.b);
+ 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);
+ u32 relid = dev->channel->offermsg.child_relid;
+
+ if (child_device->driver) {
+ drv = drv_to_hv_drv(child_device->driver);
+ if (drv->remove)
+ drv->remove(dev);
+ else {
+ hv_process_channel_removal(dev->channel, relid);
+ pr_err("remove not set for driver %s\n",
+ dev_name(child_device));
+ }
+ } else {
+ /*
+ * We don't have a driver for this device; deal with the
+ * rescind message by removing the channel.
+ */
+ hv_process_channel_removal(dev->channel, relid);
+ }
+
+ 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);
+
+ return;
+}
+
+
+/*
+ * 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);
+
+ 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_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, int cpu)
+{
+ struct clock_event_device *dev = hv_context.clk_evt[cpu];
+
+ if (dev->event_handler)
+ dev->event_handler(dev);
+
+ msg->header.message_type = HVMSG_NONE;
+
+ /*
+ * Make sure the write to MessageType (ie set to
+ * HVMSG_NONE) happens before we read the
+ * MessagePending and EOMing. Otherwise, the EOMing
+ * will not deliver any more messages since there is
+ * no empty slot
+ */
+ mb();
+
+ if (msg->header.message_flags.msg_pending) {
+ /*
+ * This will cause message queue rescan to
+ * possibly deliver another msg from the
+ * hypervisor
+ */
+ wrmsrl(HV_X64_MSR_EOM, 0);
+ }
+}
+
+static void vmbus_on_msg_dpc(unsigned long data)
+{
+ int cpu = smp_processor_id();
+ void *page_addr = hv_context.synic_message_page[cpu];
+ struct hv_message *msg = (struct hv_message *)page_addr +
+ VMBUS_MESSAGE_SINT;
+ struct vmbus_channel_message_header *hdr;
+ struct vmbus_channel_message_table_entry *entry;
+ struct onmessage_work_context *ctx;
+
+ while (1) {
+ if (msg->header.message_type == HVMSG_NONE)
+ /* no msg */
+ break;
+
+ hdr = (struct vmbus_channel_message_header *)msg->u.payload;
+
+ 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)
+ continue;
+
+ INIT_WORK(&ctx->work, vmbus_onmessage_work);
+ memcpy(&ctx->msg, msg, sizeof(*msg));
+
+ queue_work(vmbus_connection.work_queue, &ctx->work);
+ } else
+ entry->message_handler(hdr);
+
+msg_handled:
+ msg->header.message_type = HVMSG_NONE;
+
+ /*
+ * Make sure the write to MessageType (ie set to
+ * HVMSG_NONE) happens before we read the
+ * MessagePending and EOMing. Otherwise, the EOMing
+ * will not deliver any more messages since there is
+ * no empty slot
+ */
+ mb();
+
+ if (msg->header.message_flags.msg_pending) {
+ /*
+ * This will cause message queue rescan to
+ * possibly deliver another msg from the
+ * hypervisor
+ */
+ wrmsrl(HV_X64_MSR_EOM, 0);
+ }
+ }
+}
+
+static void vmbus_isr(void)
+{
+ int cpu = smp_processor_id();
+ void *page_addr;
+ struct hv_message *msg;
+ union hv_synic_event_flags *event;
+ bool handled = false;
+
+ page_addr = hv_context.synic_event_page[cpu];
+ if (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,
+ (unsigned long *) &event->flags32[0])) {
+ 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)
+ tasklet_schedule(hv_context.event_dpc[cpu]);
+
+
+ page_addr = hv_context.synic_message_page[cpu];
+ 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, cpu);
+ else
+ tasklet_schedule(&msg_dpc);
+ }
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static int hyperv_cpu_disable(void)
+{
+ return -ENOSYS;
+}
+
+static void hv_cpu_hotplug_quirk(bool vmbus_loaded)
+{
+ static void *previous_cpu_disable;
+
+ /*
+ * Offlining a CPU when running on newer hypervisors (WS2012R2, Win8,
+ * ...) is not supported at this moment as channel interrupts are
+ * distributed across all of them.
+ */
+
+ if ((vmbus_proto_version == VERSION_WS2008) ||
+ (vmbus_proto_version == VERSION_WIN7))
+ return;
+
+ if (vmbus_loaded) {
+ previous_cpu_disable = smp_ops.cpu_disable;
+ smp_ops.cpu_disable = hyperv_cpu_disable;
+ pr_notice("CPU offlining is not supported by hypervisor\n");
+ } else if (previous_cpu_disable)
+ smp_ops.cpu_disable = previous_cpu_disable;
+}
+#else
+static void hv_cpu_hotplug_quirk(bool vmbus_loaded)
+{
+}
+#endif
+
+/*
+ * vmbus_bus_init -Main vmbus driver initialization routine.
+ *
+ * Here, we
+ * - initialize the vmbus driver context
+ * - invoke the vmbus hv main init routine
+ * - get the irq resource
+ * - retrieve the channel offers
+ */
+static int vmbus_bus_init(int irq)
+{
+ 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;
+ }
+
+ tasklet_init(&msg_dpc, vmbus_on_msg_dpc, 0);
+
+ ret = bus_register(&hv_bus);
+ if (ret)
+ goto err_cleanup;
+
+ 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.
+ */
+ on_each_cpu(hv_synic_init, NULL, 1);
+ ret = vmbus_connect();
+ if (ret)
+ goto err_alloc;
+
+ hv_cpu_hotplug_quirk(true);
+
+ /*
+ * Only register if the crash MSRs are available
+ */
+ if (ms_hyperv.features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
+ atomic_notifier_chain_register(&panic_notifier_list,
+ &hyperv_panic_block);
+ }
+
+ vmbus_request_offers();
+
+ return 0;
+
+err_alloc:
+ hv_synic_free();
+ hv_remove_vmbus_irq();
+
+ bus_unregister(&hv_bus);
+
+err_cleanup:
+ hv_cleanup();
+
+ return ret;
+}
+
+/**
+ * __vmbus_child_driver_register - Register a vmbus's driver
+ * @drv: 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;
+
+ ret = driver_register(&hv_driver->driver);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__vmbus_driver_register);
+
+/**
+ * vmbus_driver_unregister() - Unregister a vmbus's driver
+ * @drv: 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);
+}
+EXPORT_SYMBOL_GPL(vmbus_driver_unregister);
+
+/*
+ * vmbus_device_create - Creates and registers a new child device
+ * on the vmbus.
+ */
+struct hv_device *vmbus_device_create(const uuid_le *type,
+ const uuid_le *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;
+ memcpy(&child_device_obj->dev_type, type, sizeof(uuid_le));
+ memcpy(&child_device_obj->dev_instance, instance,
+ sizeof(uuid_le));
+
+
+ return child_device_obj;
+}
+
+/*
+ * vmbus_device_register - Register the child device
+ */
+int vmbus_device_register(struct hv_device *child_device_obj)
+{
+ int ret = 0;
+
+ dev_set_name(&child_device_obj->device, "vmbus_%d",
+ child_device_obj->channel->id);
+
+ 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");
+ else
+ pr_debug("child device %s registered\n",
+ dev_name(&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));
+
+ /*
+ * 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 the information we
+ * need from DSDT.
+ */
+
+static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
+{
+ switch (res->type) {
+ case ACPI_RESOURCE_TYPE_IRQ:
+ irq = res->data.irq.interrupts[0];
+ break;
+
+ case ACPI_RESOURCE_TYPE_ADDRESS64:
+ hyperv_mmio.start = res->data.address64.address.minimum;
+ hyperv_mmio.end = res->data.address64.address.maximum;
+ break;
+ }
+
+ return AE_OK;
+}
+
+static int vmbus_acpi_add(struct acpi_device *device)
+{
+ acpi_status result;
+ int ret_val = -ENODEV;
+
+ 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;
+ /*
+ * The parent of the vmbus acpi device (Gen2 firmware) is the VMOD that
+ * has the mmio ranges. Get that.
+ */
+ if (device->parent) {
+ result = acpi_walk_resources(device->parent->handle,
+ METHOD_NAME__CRS,
+ vmbus_walk_resources, NULL);
+
+ if (ACPI_FAILURE(result))
+ goto acpi_walk_err;
+ if (hyperv_mmio.start && hyperv_mmio.end)
+ request_resource(&iomem_resource, &hyperv_mmio);
+ }
+ ret_val = 0;
+
+acpi_walk_err:
+ complete(&probe_event);
+ 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,
+ },
+};
+
+static int __init hv_acpi_init(void)
+{
+ int ret, t;
+
+ if (x86_hyper != &x86_hyper_ms_hyperv)
+ return -ENODEV;
+
+ init_completion(&probe_event);
+
+ /*
+ * Get irq 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;
+ }
+
+ if (irq <= 0) {
+ ret = -ENODEV;
+ goto cleanup;
+ }
+
+ ret = vmbus_bus_init(irq);
+ if (ret)
+ goto cleanup;
+
+ return 0;
+
+cleanup:
+ acpi_bus_unregister_driver(&vmbus_acpi_driver);
+ hv_acpi_dev = NULL;
+ return ret;
+}
+
+static void __exit vmbus_exit(void)
+{
+ int cpu;
+
+ vmbus_connection.conn_state = DISCONNECTED;
+ hv_synic_clockevents_cleanup();
+ hv_remove_vmbus_irq();
+ vmbus_free_channels();
+ bus_unregister(&hv_bus);
+ hv_cleanup();
+ for_each_online_cpu(cpu)
+ smp_call_function_single(cpu, hv_synic_cleanup, NULL, 1);
+ acpi_bus_unregister_driver(&vmbus_acpi_driver);
+ hv_cpu_hotplug_quirk(false);
+ vmbus_disconnect();
+}
+
+
+MODULE_LICENSE("GPL");
+
+subsys_initcall(hv_acpi_init);
+module_exit(vmbus_exit);