/drivers/hv/connection.c
C | 467 lines | 280 code | 78 blank | 109 comment | 55 complexity | a8bb0f62da779a366cf29d9a8714e1e6 MD5 | raw file
- // SPDX-License-Identifier: GPL-2.0-only
- /*
- *
- * Copyright (c) 2009, Microsoft Corporation.
- *
- * 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/mshyperv.h>
- #include "hyperv_vmbus.h"
- struct vmbus_connection vmbus_connection = {
- .conn_state = DISCONNECTED,
- .next_gpadl_handle = ATOMIC_INIT(0xE1E10),
- };
- EXPORT_SYMBOL_GPL(vmbus_connection);
- /*
- * 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_WIN10):
- return VERSION_WIN8_1;
- case (VERSION_WIN10_V5):
- return VERSION_WIN10;
- case (VERSION_WS2008):
- default:
- return VERSION_INVAL;
- }
- }
- static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
- __u32 version)
- {
- int ret = 0;
- unsigned int cur_cpu;
- struct vmbus_channel_initiate_contact *msg;
- unsigned long flags;
- init_completion(&msginfo->waitevent);
- msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
- memset(msg, 0, sizeof(*msg));
- msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
- msg->vmbus_version_requested = version;
- /*
- * VMBus protocol 5.0 (VERSION_WIN10_V5) requires that we must use
- * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,
- * and for subsequent messages, we must use the Message Connection ID
- * field in the host-returned Version Response Message. And, with
- * VERSION_WIN10_V5, we don't use msg->interrupt_page, but we tell
- * the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for
- * compatibility.
- *
- * On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1).
- */
- if (version >= VERSION_WIN10_V5) {
- msg->msg_sint = VMBUS_MESSAGE_SINT;
- vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
- } else {
- msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
- vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID;
- }
- msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
- msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
- /*
- * We want all channel messages to be delivered on CPU 0.
- * This has been the behavior pre-win8. This is not
- * perf issue and having all channel messages delivered on CPU 0
- * would be ok.
- * For post win8 hosts, we support receiving channel messagges on
- * all the CPUs. This is needed for kexec to work correctly where
- * the CPU attempting to connect may not be CPU 0.
- */
- if (version >= VERSION_WIN8_1) {
- cur_cpu = get_cpu();
- msg->target_vcpu = hv_cpu_number_to_vp_number(cur_cpu);
- vmbus_connection.connect_cpu = cur_cpu;
- put_cpu();
- } else {
- msg->target_vcpu = 0;
- vmbus_connection.connect_cpu = 0;
- }
- /*
- * 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),
- true);
- trace_vmbus_negotiate_version(msg, ret);
- 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;
- if (version >= VERSION_WIN10_V5)
- vmbus_connection.msg_conn_id =
- msginfo->response.version_response.msg_conn_id;
- } 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;
- }
- vmbus_connection.handle_primary_chan_wq =
- create_workqueue("hv_pri_chan");
- if (!vmbus_connection.handle_primary_chan_wq) {
- ret = -ENOMEM;
- goto cleanup;
- }
- vmbus_connection.handle_sub_chan_wq =
- create_workqueue("hv_sub_chan");
- if (!vmbus_connection.handle_sub_chan_wq) {
- 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);
- mutex_init(&vmbus_connection.channel_mutex);
- /*
- * 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("Vmbus version:%d.%d\n",
- version >> 16, version & 0xFFFF);
- kfree(msginfo);
- return 0;
- cleanup:
- pr_err("Unable to connect to host\n");
- vmbus_connection.conn_state = DISCONNECTED;
- vmbus_disconnect();
- kfree(msginfo);
- return ret;
- }
- void vmbus_disconnect(void)
- {
- /*
- * First send the unload request to the host.
- */
- vmbus_initiate_unload(false);
- if (vmbus_connection.handle_sub_chan_wq)
- destroy_workqueue(vmbus_connection.handle_sub_chan_wq);
- if (vmbus_connection.handle_primary_chan_wq)
- destroy_workqueue(vmbus_connection.handle_primary_chan_wq);
- 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;
- }
- /*
- * 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;
- struct list_head *cur, *tmp;
- struct vmbus_channel *cur_sc;
- BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex));
- 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;
- }
- }
- }
- }
- return found_channel;
- }
- /*
- * vmbus_on_event - Process a channel event notification
- *
- * For batched channels (default) 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.
- * If this tasklet has been running for a long time
- * then reschedule ourselves.
- */
- void vmbus_on_event(unsigned long data)
- {
- struct vmbus_channel *channel = (void *) data;
- unsigned long time_limit = jiffies + 2;
- trace_vmbus_on_event(channel);
- do {
- void (*callback_fn)(void *);
- /* A channel once created is persistent even when
- * there is no driver handling the device. An
- * unloading driver sets the onchannel_callback to NULL.
- */
- callback_fn = READ_ONCE(channel->onchannel_callback);
- if (unlikely(callback_fn == NULL))
- return;
- (*callback_fn)(channel->channel_callback_context);
- if (channel->callback_mode != HV_CALL_BATCHED)
- return;
- if (likely(hv_end_read(&channel->inbound) == 0))
- return;
- hv_begin_read(&channel->inbound);
- } while (likely(time_before(jiffies, time_limit)));
- /* The time limit (2 jiffies) has been reached */
- tasklet_schedule(&channel->callback_event);
- }
- /*
- * vmbus_post_msg - Send a msg on the vmbus's message connection
- */
- int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
- {
- struct vmbus_channel_message_header *hdr;
- union hv_connection_id conn_id;
- int ret = 0;
- int retries = 0;
- u32 usec = 1;
- conn_id.asu32 = 0;
- conn_id.u.id = vmbus_connection.msg_conn_id;
- /*
- * hv_post_message() can have transient failures because of
- * insufficient resources. Retry the operation a couple of
- * times before giving up.
- */
- while (retries < 100) {
- ret = hv_post_message(conn_id, 1, buffer, buflen);
- switch (ret) {
- case HV_STATUS_INVALID_CONNECTION_ID:
- /*
- * See vmbus_negotiate_version(): VMBus protocol 5.0
- * requires that we must use
- * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
- * Contact message, but on old hosts that only
- * support VMBus protocol 4.0 or lower, here we get
- * HV_STATUS_INVALID_CONNECTION_ID and we should
- * return an error immediately without retrying.
- */
- hdr = buffer;
- if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT)
- return -EINVAL;
- /*
- * We could get this if we send messages too
- * frequently.
- */
- ret = -EAGAIN;
- break;
- case HV_STATUS_INSUFFICIENT_MEMORY:
- case HV_STATUS_INSUFFICIENT_BUFFERS:
- ret = -ENOBUFS;
- break;
- case HV_STATUS_SUCCESS:
- return ret;
- default:
- pr_err("hv_post_msg() failed; error code:%d\n", ret);
- return -EINVAL;
- }
- retries++;
- if (can_sleep && usec > 1000)
- msleep(usec / 1000);
- else if (usec < MAX_UDELAY_MS * 1000)
- udelay(usec);
- else
- mdelay(usec / 1000);
- if (retries < 22)
- usec *= 2;
- }
- return ret;
- }
- /*
- * vmbus_set_event - Send an event notification to the parent
- */
- void vmbus_set_event(struct vmbus_channel *channel)
- {
- u32 child_relid = channel->offermsg.child_relid;
- if (!channel->is_dedicated_interrupt)
- vmbus_send_interrupt(child_relid);
- ++channel->sig_events;
- hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
- }
- EXPORT_SYMBOL_GPL(vmbus_set_event);