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447 lines
12 KiB
447 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* |
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* Copyright (c) 2009, Microsoft Corporation. |
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* |
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* Authors: |
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* Haiyang Zhang <[email protected]> |
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* Hank Janssen <[email protected]> |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/kernel.h> |
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#include <linux/sched.h> |
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#include <linux/wait.h> |
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#include <linux/delay.h> |
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#include <linux/mm.h> |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <linux/vmalloc.h> |
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#include <linux/hyperv.h> |
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#include <linux/export.h> |
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#include <asm/mshyperv.h> |
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#include "hyperv_vmbus.h" |
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struct vmbus_connection vmbus_connection = { |
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.conn_state = DISCONNECTED, |
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.next_gpadl_handle = ATOMIC_INIT(0xE1E10), |
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.ready_for_suspend_event= COMPLETION_INITIALIZER( |
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vmbus_connection.ready_for_suspend_event), |
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.ready_for_resume_event = COMPLETION_INITIALIZER( |
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vmbus_connection.ready_for_resume_event), |
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}; |
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EXPORT_SYMBOL_GPL(vmbus_connection); |
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/* |
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* Negotiated protocol version with the host. |
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*/ |
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__u32 vmbus_proto_version; |
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EXPORT_SYMBOL_GPL(vmbus_proto_version); |
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/* |
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* Table of VMBus versions listed from newest to oldest. |
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*/ |
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static __u32 vmbus_versions[] = { |
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VERSION_WIN10_V5_2, |
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VERSION_WIN10_V5_1, |
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VERSION_WIN10_V5, |
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VERSION_WIN10_V4_1, |
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VERSION_WIN10, |
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VERSION_WIN8_1, |
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VERSION_WIN8, |
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VERSION_WIN7, |
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VERSION_WS2008 |
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}; |
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/* |
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* Maximal VMBus protocol version guests can negotiate. Useful to cap the |
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* VMBus version for testing and debugging purpose. |
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*/ |
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static uint max_version = VERSION_WIN10_V5_2; |
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module_param(max_version, uint, S_IRUGO); |
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MODULE_PARM_DESC(max_version, |
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"Maximal VMBus protocol version which can be negotiated"); |
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int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version) |
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{ |
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int ret = 0; |
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struct vmbus_channel_initiate_contact *msg; |
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unsigned long flags; |
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init_completion(&msginfo->waitevent); |
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msg = (struct vmbus_channel_initiate_contact *)msginfo->msg; |
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memset(msg, 0, sizeof(*msg)); |
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msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT; |
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msg->vmbus_version_requested = version; |
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/* |
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* VMBus protocol 5.0 (VERSION_WIN10_V5) and higher require that we must |
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* use VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message, |
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* and for subsequent messages, we must use the Message Connection ID |
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* field in the host-returned Version Response Message. And, with |
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* VERSION_WIN10_V5 and higher, we don't use msg->interrupt_page, but we |
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* tell the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for |
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* compatibility. |
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* |
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* On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1). |
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*/ |
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if (version >= VERSION_WIN10_V5) { |
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msg->msg_sint = VMBUS_MESSAGE_SINT; |
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vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4; |
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} else { |
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msg->interrupt_page = virt_to_phys(vmbus_connection.int_page); |
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vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID; |
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} |
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msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]); |
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msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]); |
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msg->target_vcpu = hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU); |
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/* |
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* Add to list before we send the request since we may |
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* receive the response before returning from this routine |
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*/ |
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spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); |
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list_add_tail(&msginfo->msglistentry, |
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&vmbus_connection.chn_msg_list); |
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spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); |
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ret = vmbus_post_msg(msg, |
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sizeof(struct vmbus_channel_initiate_contact), |
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true); |
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trace_vmbus_negotiate_version(msg, ret); |
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if (ret != 0) { |
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spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); |
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list_del(&msginfo->msglistentry); |
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spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, |
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flags); |
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return ret; |
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} |
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/* Wait for the connection response */ |
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wait_for_completion(&msginfo->waitevent); |
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spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); |
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list_del(&msginfo->msglistentry); |
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spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); |
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/* Check if successful */ |
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if (msginfo->response.version_response.version_supported) { |
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vmbus_connection.conn_state = CONNECTED; |
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if (version >= VERSION_WIN10_V5) |
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vmbus_connection.msg_conn_id = |
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msginfo->response.version_response.msg_conn_id; |
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} else { |
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return -ECONNREFUSED; |
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} |
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return ret; |
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} |
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/* |
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* vmbus_connect - Sends a connect request on the partition service connection |
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*/ |
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int vmbus_connect(void) |
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{ |
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struct vmbus_channel_msginfo *msginfo = NULL; |
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int i, ret = 0; |
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__u32 version; |
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/* Initialize the vmbus connection */ |
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vmbus_connection.conn_state = CONNECTING; |
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vmbus_connection.work_queue = create_workqueue("hv_vmbus_con"); |
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if (!vmbus_connection.work_queue) { |
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ret = -ENOMEM; |
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goto cleanup; |
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} |
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vmbus_connection.handle_primary_chan_wq = |
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create_workqueue("hv_pri_chan"); |
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if (!vmbus_connection.handle_primary_chan_wq) { |
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ret = -ENOMEM; |
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goto cleanup; |
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} |
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vmbus_connection.handle_sub_chan_wq = |
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create_workqueue("hv_sub_chan"); |
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if (!vmbus_connection.handle_sub_chan_wq) { |
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ret = -ENOMEM; |
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goto cleanup; |
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} |
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INIT_LIST_HEAD(&vmbus_connection.chn_msg_list); |
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spin_lock_init(&vmbus_connection.channelmsg_lock); |
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INIT_LIST_HEAD(&vmbus_connection.chn_list); |
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mutex_init(&vmbus_connection.channel_mutex); |
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/* |
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* Setup the vmbus event connection for channel interrupt |
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* abstraction stuff |
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*/ |
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vmbus_connection.int_page = |
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(void *)hv_alloc_hyperv_zeroed_page(); |
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if (vmbus_connection.int_page == NULL) { |
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ret = -ENOMEM; |
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goto cleanup; |
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} |
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vmbus_connection.recv_int_page = vmbus_connection.int_page; |
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vmbus_connection.send_int_page = |
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(void *)((unsigned long)vmbus_connection.int_page + |
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(HV_HYP_PAGE_SIZE >> 1)); |
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/* |
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* Setup the monitor notification facility. The 1st page for |
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* parent->child and the 2nd page for child->parent |
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*/ |
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vmbus_connection.monitor_pages[0] = (void *)hv_alloc_hyperv_zeroed_page(); |
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vmbus_connection.monitor_pages[1] = (void *)hv_alloc_hyperv_zeroed_page(); |
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if ((vmbus_connection.monitor_pages[0] == NULL) || |
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(vmbus_connection.monitor_pages[1] == NULL)) { |
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ret = -ENOMEM; |
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goto cleanup; |
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} |
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msginfo = kzalloc(sizeof(*msginfo) + |
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sizeof(struct vmbus_channel_initiate_contact), |
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GFP_KERNEL); |
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if (msginfo == NULL) { |
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ret = -ENOMEM; |
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goto cleanup; |
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} |
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/* |
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* Negotiate a compatible VMBUS version number with the |
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* host. We start with the highest number we can support |
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* and work our way down until we negotiate a compatible |
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* version. |
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*/ |
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for (i = 0; ; i++) { |
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if (i == ARRAY_SIZE(vmbus_versions)) |
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goto cleanup; |
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version = vmbus_versions[i]; |
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if (version > max_version) |
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continue; |
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ret = vmbus_negotiate_version(msginfo, version); |
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if (ret == -ETIMEDOUT) |
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goto cleanup; |
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if (vmbus_connection.conn_state == CONNECTED) |
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break; |
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} |
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if (hv_is_isolation_supported() && version < VERSION_WIN10_V5_2) { |
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pr_err("Invalid VMBus version %d.%d (expected >= %d.%d) from the host supporting isolation\n", |
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version >> 16, version & 0xFFFF, VERSION_WIN10_V5_2 >> 16, VERSION_WIN10_V5_2 & 0xFFFF); |
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ret = -EINVAL; |
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goto cleanup; |
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} |
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vmbus_proto_version = version; |
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pr_info("Vmbus version:%d.%d\n", |
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version >> 16, version & 0xFFFF); |
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vmbus_connection.channels = kcalloc(MAX_CHANNEL_RELIDS, |
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sizeof(struct vmbus_channel *), |
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GFP_KERNEL); |
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if (vmbus_connection.channels == NULL) { |
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ret = -ENOMEM; |
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goto cleanup; |
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} |
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kfree(msginfo); |
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return 0; |
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cleanup: |
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pr_err("Unable to connect to host\n"); |
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vmbus_connection.conn_state = DISCONNECTED; |
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vmbus_disconnect(); |
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kfree(msginfo); |
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return ret; |
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} |
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void vmbus_disconnect(void) |
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{ |
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/* |
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* First send the unload request to the host. |
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*/ |
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vmbus_initiate_unload(false); |
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if (vmbus_connection.handle_sub_chan_wq) |
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destroy_workqueue(vmbus_connection.handle_sub_chan_wq); |
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if (vmbus_connection.handle_primary_chan_wq) |
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destroy_workqueue(vmbus_connection.handle_primary_chan_wq); |
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if (vmbus_connection.work_queue) |
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destroy_workqueue(vmbus_connection.work_queue); |
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if (vmbus_connection.int_page) { |
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hv_free_hyperv_page((unsigned long)vmbus_connection.int_page); |
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vmbus_connection.int_page = NULL; |
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} |
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hv_free_hyperv_page((unsigned long)vmbus_connection.monitor_pages[0]); |
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hv_free_hyperv_page((unsigned long)vmbus_connection.monitor_pages[1]); |
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vmbus_connection.monitor_pages[0] = NULL; |
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vmbus_connection.monitor_pages[1] = NULL; |
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} |
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/* |
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* relid2channel - Get the channel object given its |
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* child relative id (ie channel id) |
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*/ |
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struct vmbus_channel *relid2channel(u32 relid) |
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{ |
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if (WARN_ON(relid >= MAX_CHANNEL_RELIDS)) |
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return NULL; |
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return READ_ONCE(vmbus_connection.channels[relid]); |
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} |
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/* |
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* vmbus_on_event - Process a channel event notification |
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* |
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* For batched channels (default) optimize host to guest signaling |
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* by ensuring: |
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* 1. While reading the channel, we disable interrupts from host. |
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* 2. Ensure that we process all posted messages from the host |
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* before returning from this callback. |
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* 3. Once we return, enable signaling from the host. Once this |
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* state is set we check to see if additional packets are |
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* available to read. In this case we repeat the process. |
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* If this tasklet has been running for a long time |
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* then reschedule ourselves. |
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*/ |
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void vmbus_on_event(unsigned long data) |
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{ |
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struct vmbus_channel *channel = (void *) data; |
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unsigned long time_limit = jiffies + 2; |
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trace_vmbus_on_event(channel); |
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hv_debug_delay_test(channel, INTERRUPT_DELAY); |
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do { |
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void (*callback_fn)(void *); |
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/* A channel once created is persistent even when |
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* there is no driver handling the device. An |
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* unloading driver sets the onchannel_callback to NULL. |
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*/ |
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callback_fn = READ_ONCE(channel->onchannel_callback); |
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if (unlikely(callback_fn == NULL)) |
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return; |
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(*callback_fn)(channel->channel_callback_context); |
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if (channel->callback_mode != HV_CALL_BATCHED) |
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return; |
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if (likely(hv_end_read(&channel->inbound) == 0)) |
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return; |
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hv_begin_read(&channel->inbound); |
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} while (likely(time_before(jiffies, time_limit))); |
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/* The time limit (2 jiffies) has been reached */ |
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tasklet_schedule(&channel->callback_event); |
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} |
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/* |
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* vmbus_post_msg - Send a msg on the vmbus's message connection |
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*/ |
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int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep) |
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{ |
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struct vmbus_channel_message_header *hdr; |
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union hv_connection_id conn_id; |
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int ret = 0; |
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int retries = 0; |
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u32 usec = 1; |
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conn_id.asu32 = 0; |
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conn_id.u.id = vmbus_connection.msg_conn_id; |
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/* |
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* hv_post_message() can have transient failures because of |
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* insufficient resources. Retry the operation a couple of |
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* times before giving up. |
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*/ |
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while (retries < 100) { |
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ret = hv_post_message(conn_id, 1, buffer, buflen); |
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switch (ret) { |
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case HV_STATUS_INVALID_CONNECTION_ID: |
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/* |
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* See vmbus_negotiate_version(): VMBus protocol 5.0 |
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* and higher require that we must use |
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* VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate |
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* Contact message, but on old hosts that only |
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* support VMBus protocol 4.0 or lower, here we get |
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* HV_STATUS_INVALID_CONNECTION_ID and we should |
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* return an error immediately without retrying. |
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*/ |
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hdr = buffer; |
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if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT) |
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return -EINVAL; |
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/* |
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* We could get this if we send messages too |
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* frequently. |
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*/ |
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ret = -EAGAIN; |
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break; |
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case HV_STATUS_INSUFFICIENT_MEMORY: |
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case HV_STATUS_INSUFFICIENT_BUFFERS: |
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ret = -ENOBUFS; |
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break; |
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case HV_STATUS_SUCCESS: |
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return ret; |
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default: |
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pr_err("hv_post_msg() failed; error code:%d\n", ret); |
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return -EINVAL; |
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} |
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retries++; |
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if (can_sleep && usec > 1000) |
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msleep(usec / 1000); |
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else if (usec < MAX_UDELAY_MS * 1000) |
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udelay(usec); |
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else |
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mdelay(usec / 1000); |
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if (retries < 22) |
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usec *= 2; |
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} |
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return ret; |
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} |
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/* |
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* vmbus_set_event - Send an event notification to the parent |
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*/ |
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void vmbus_set_event(struct vmbus_channel *channel) |
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{ |
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u32 child_relid = channel->offermsg.child_relid; |
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if (!channel->is_dedicated_interrupt) |
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vmbus_send_interrupt(child_relid); |
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++channel->sig_events; |
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hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event); |
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} |
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EXPORT_SYMBOL_GPL(vmbus_set_event);
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