505 lines
13 KiB
C
505 lines
13 KiB
C
/*
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*
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* Copyright (c) 2009, Microsoft Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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* Place - Suite 330, Boston, MA 02111-1307 USA.
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*
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* Authors:
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* Haiyang Zhang <haiyangz@microsoft.com>
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* Hank Janssen <hjanssen@microsoft.com>
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*
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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/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/hyperv.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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};
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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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static __u32 vmbus_get_next_version(__u32 current_version)
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{
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switch (current_version) {
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case (VERSION_WIN7):
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return VERSION_WS2008;
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case (VERSION_WIN8):
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return VERSION_WIN7;
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case (VERSION_WIN8_1):
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return VERSION_WIN8;
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case (VERSION_WIN10):
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return VERSION_WIN8_1;
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case (VERSION_WS2008):
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default:
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return VERSION_INVAL;
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}
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}
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static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
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__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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msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
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msg->vmbus_version_requested = version;
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msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
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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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/*
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* We want all channel messages to be delivered on CPU 0.
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* This has been the behavior pre-win8. This is not
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* perf issue and having all channel messages delivered on CPU 0
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* would be ok.
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* For post win8 hosts, we support receiving channel messagges on
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* all the CPUs. This is needed for kexec to work correctly where
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* the CPU attempting to connect may not be CPU 0.
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*/
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if (version >= VERSION_WIN8_1) {
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msg->target_vcpu = hv_context.vp_index[get_cpu()];
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put_cpu();
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} else {
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msg->target_vcpu = 0;
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}
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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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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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} 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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int ret = 0;
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struct vmbus_channel_msginfo *msginfo = NULL;
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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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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 *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
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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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(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 *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
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vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
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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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version = VERSION_CURRENT;
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do {
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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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version = vmbus_get_next_version(version);
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} while (version != VERSION_INVAL);
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if (version == VERSION_INVAL)
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goto cleanup;
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vmbus_proto_version = version;
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pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n",
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host_info_eax, host_info_ebx >> 16,
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host_info_ebx & 0xFFFF, host_info_ecx,
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host_info_edx >> 24, host_info_edx & 0xFFFFFF,
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version >> 16, version & 0xFFFF);
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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.work_queue) {
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drain_workqueue(vmbus_connection.work_queue);
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destroy_workqueue(vmbus_connection.work_queue);
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}
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if (vmbus_connection.int_page) {
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free_pages((unsigned long)vmbus_connection.int_page, 0);
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vmbus_connection.int_page = NULL;
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}
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free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
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free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
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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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* Map the given relid to the corresponding channel based on the
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* per-cpu list of channels that have been affinitized to this CPU.
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* This will be used in the channel callback path as we can do this
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* mapping in a lock-free fashion.
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*/
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static struct vmbus_channel *pcpu_relid2channel(u32 relid)
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{
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struct vmbus_channel *channel;
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struct vmbus_channel *found_channel = NULL;
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int cpu = smp_processor_id();
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struct list_head *pcpu_head = &hv_context.percpu_list[cpu];
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list_for_each_entry(channel, pcpu_head, percpu_list) {
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if (channel->offermsg.child_relid == relid) {
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found_channel = channel;
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break;
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}
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}
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return found_channel;
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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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struct vmbus_channel *channel;
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struct vmbus_channel *found_channel = NULL;
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struct list_head *cur, *tmp;
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struct vmbus_channel *cur_sc;
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BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex));
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list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
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if (channel->offermsg.child_relid == relid) {
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found_channel = channel;
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break;
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} else if (!list_empty(&channel->sc_list)) {
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/*
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* Deal with sub-channels.
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*/
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list_for_each_safe(cur, tmp, &channel->sc_list) {
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cur_sc = list_entry(cur, struct vmbus_channel,
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sc_list);
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if (cur_sc->offermsg.child_relid == relid) {
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found_channel = cur_sc;
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break;
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}
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}
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}
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}
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return found_channel;
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}
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/*
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* process_chn_event - Process a channel event notification
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*/
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static void process_chn_event(u32 relid)
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{
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struct vmbus_channel *channel;
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void *arg;
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bool read_state;
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u32 bytes_to_read;
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/*
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* Find the channel based on this relid and invokes the
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* channel callback to process the event
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*/
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channel = pcpu_relid2channel(relid);
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if (!channel)
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return;
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/*
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* A channel once created is persistent even when there
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* is no driver handling the device. An unloading driver
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* sets the onchannel_callback to NULL on the same CPU
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* as where this interrupt is handled (in an interrupt context).
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* Thus, checking and invoking the driver specific callback takes
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* care of orderly unloading of the driver.
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*/
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if (channel->onchannel_callback != NULL) {
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arg = channel->channel_callback_context;
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read_state = channel->batched_reading;
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/*
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* This callback reads the messages sent by the host.
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* We can optimize host to guest signaling by ensuring:
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* 1. While reading the channel, we disable interrupts from
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* 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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*/
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do {
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if (read_state)
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hv_begin_read(&channel->inbound);
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channel->onchannel_callback(arg);
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if (read_state)
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bytes_to_read = hv_end_read(&channel->inbound);
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else
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bytes_to_read = 0;
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} while (read_state && (bytes_to_read != 0));
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}
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}
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/*
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* vmbus_on_event - Handler for events
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*/
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void vmbus_on_event(unsigned long data)
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{
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u32 dword;
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u32 maxdword;
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int bit;
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u32 relid;
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u32 *recv_int_page = NULL;
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void *page_addr;
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int cpu = smp_processor_id();
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union hv_synic_event_flags *event;
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if (vmbus_proto_version < VERSION_WIN8) {
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maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
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recv_int_page = vmbus_connection.recv_int_page;
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} else {
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/*
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* When the host is win8 and beyond, the event page
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* can be directly checked to get the id of the channel
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* that has the interrupt pending.
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*/
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maxdword = HV_EVENT_FLAGS_DWORD_COUNT;
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page_addr = hv_context.synic_event_page[cpu];
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event = (union hv_synic_event_flags *)page_addr +
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VMBUS_MESSAGE_SINT;
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recv_int_page = event->flags32;
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}
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/* Check events */
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if (!recv_int_page)
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return;
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for (dword = 0; dword < maxdword; dword++) {
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if (!recv_int_page[dword])
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continue;
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for (bit = 0; bit < 32; bit++) {
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if (sync_test_and_clear_bit(bit,
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(unsigned long *)&recv_int_page[dword])) {
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relid = (dword << 5) + bit;
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if (relid == 0)
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/*
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* Special case - vmbus
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* channel protocol msg
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*/
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continue;
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process_chn_event(relid);
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}
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}
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}
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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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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_MESSAGE_CONNECTION_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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* 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 = -ENOMEM;
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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 (usec < 256000)
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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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/* Each u32 represents 32 channels */
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sync_set_bit(child_relid & 31,
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(unsigned long *)vmbus_connection.send_int_page +
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(child_relid >> 5));
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}
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hv_do_hypercall(HVCALL_SIGNAL_EVENT, channel->sig_event, NULL);
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}
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EXPORT_SYMBOL_GPL(vmbus_set_event);
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