| // 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), |
| |
| .ready_for_suspend_event= COMPLETION_INITIALIZER( |
| vmbus_connection.ready_for_suspend_event), |
| .ready_for_resume_event = COMPLETION_INITIALIZER( |
| vmbus_connection.ready_for_resume_event), |
| }; |
| 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; |
| } |
| } |
| |
| int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version) |
| { |
| int ret = 0; |
| struct vmbus_channel_initiate_contact *msg; |
| unsigned long flags; |
| |
| init_completion(&msginfo->waitevent); |
| |
| msg = (struct vmbus_channel_initiate_contact *)msginfo->msg; |
| |
| 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]); |
| msg->target_vcpu = hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU); |
| |
| /* |
| * 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); |