diff options
Diffstat (limited to 'drivers/hv/connection.c')
| -rw-r--r-- | drivers/hv/connection.c | 480 |
1 files changed, 480 insertions, 0 deletions
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c new file mode 100644 index 000000000..b27220a42 --- /dev/null +++ b/drivers/hv/connection.c @@ -0,0 +1,480 @@ +/* + * + * Copyright (c) 2009, Microsoft Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., 59 Temple + * Place - Suite 330, Boston, MA 02111-1307 USA. + * + * Authors: + * Haiyang Zhang <haiyangz@microsoft.com> + * Hank Janssen <hjanssen@microsoft.com> + * + */ +#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/hyperv.h> +#include "hyperv_vmbus.h" + + +struct vmbus_connection vmbus_connection = { + .conn_state = DISCONNECTED, + .next_gpadl_handle = ATOMIC_INIT(0xE1E10), +}; + +/* + * 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_WS2008): + default: + return VERSION_INVAL; + } +} + +static 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; + + msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT; + msg->vmbus_version_requested = version; + msg->interrupt_page = virt_to_phys(vmbus_connection.int_page); + msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]); + msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]); + if (version == VERSION_WIN8_1) { + msg->target_vcpu = hv_context.vp_index[get_cpu()]; + put_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)); + 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; + } 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; + } + + INIT_LIST_HEAD(&vmbus_connection.chn_msg_list); + spin_lock_init(&vmbus_connection.channelmsg_lock); + + INIT_LIST_HEAD(&vmbus_connection.chn_list); + spin_lock_init(&vmbus_connection.channel_lock); + + /* + * 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("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n", + host_info_eax, host_info_ebx >> 16, + host_info_ebx & 0xFFFF, host_info_ecx, + host_info_edx >> 24, host_info_edx & 0xFFFFFF, + 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) +{ + if (vmbus_connection.work_queue) { + drain_workqueue(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; +} + +/* + * Map the given relid to the corresponding channel based on the + * per-cpu list of channels that have been affinitized to this CPU. + * This will be used in the channel callback path as we can do this + * mapping in a lock-free fashion. + */ +static struct vmbus_channel *pcpu_relid2channel(u32 relid) +{ + struct vmbus_channel *channel; + struct vmbus_channel *found_channel = NULL; + int cpu = smp_processor_id(); + struct list_head *pcpu_head = &hv_context.percpu_list[cpu]; + + list_for_each_entry(channel, pcpu_head, percpu_list) { + if (channel->offermsg.child_relid == relid) { + found_channel = channel; + break; + } + } + + return found_channel; +} + +/* + * 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; + unsigned long flags; + struct list_head *cur, *tmp; + struct vmbus_channel *cur_sc; + + spin_lock_irqsave(&vmbus_connection.channel_lock, flags); + 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; + } + } + } + } + spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags); + + return found_channel; +} + +/* + * process_chn_event - Process a channel event notification + */ +static void process_chn_event(u32 relid) +{ + struct vmbus_channel *channel; + void *arg; + bool read_state; + u32 bytes_to_read; + + /* + * Find the channel based on this relid and invokes the + * channel callback to process the event + */ + channel = pcpu_relid2channel(relid); + + if (!channel) + return; + + /* + * A channel once created is persistent even when there + * is no driver handling the device. An unloading driver + * sets the onchannel_callback to NULL on the same CPU + * as where this interrupt is handled (in an interrupt context). + * Thus, checking and invoking the driver specific callback takes + * care of orderly unloading of the driver. + */ + + if (channel->onchannel_callback != NULL) { + arg = channel->channel_callback_context; + read_state = channel->batched_reading; + /* + * This callback reads the messages sent by the host. + * We can 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. + */ + + do { + if (read_state) + hv_begin_read(&channel->inbound); + channel->onchannel_callback(arg); + if (read_state) + bytes_to_read = hv_end_read(&channel->inbound); + else + bytes_to_read = 0; + } while (read_state && (bytes_to_read != 0)); + } +} + +/* + * vmbus_on_event - Handler for events + */ +void vmbus_on_event(unsigned long data) +{ + u32 dword; + u32 maxdword; + int bit; + u32 relid; + u32 *recv_int_page = NULL; + void *page_addr; + int cpu = smp_processor_id(); + union hv_synic_event_flags *event; + + if ((vmbus_proto_version == VERSION_WS2008) || + (vmbus_proto_version == VERSION_WIN7)) { + maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5; + recv_int_page = vmbus_connection.recv_int_page; + } else { + /* + * When the host is win8 and beyond, the event page + * can be directly checked to get the id of the channel + * that has the interrupt pending. + */ + maxdword = HV_EVENT_FLAGS_DWORD_COUNT; + page_addr = hv_context.synic_event_page[cpu]; + event = (union hv_synic_event_flags *)page_addr + + VMBUS_MESSAGE_SINT; + recv_int_page = event->flags32; + } + + + + /* Check events */ + if (!recv_int_page) + return; + for (dword = 0; dword < maxdword; dword++) { + if (!recv_int_page[dword]) + continue; + for (bit = 0; bit < 32; bit++) { + if (sync_test_and_clear_bit(bit, + (unsigned long *)&recv_int_page[dword])) { + relid = (dword << 5) + bit; + + if (relid == 0) + /* + * Special case - vmbus + * channel protocol msg + */ + continue; + + process_chn_event(relid); + } + } + } +} + +/* + * vmbus_post_msg - Send a msg on the vmbus's message connection + */ +int vmbus_post_msg(void *buffer, size_t buflen) +{ + union hv_connection_id conn_id; + int ret = 0; + int retries = 0; + u32 msec = 1; + + conn_id.asu32 = 0; + conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID; + + /* + * hv_post_message() can have transient failures because of + * insufficient resources. Retry the operation a couple of + * times before giving up. + */ + while (retries < 20) { + ret = hv_post_message(conn_id, 1, buffer, buflen); + + switch (ret) { + case HV_STATUS_INVALID_CONNECTION_ID: + /* + * We could get this if we send messages too + * frequently. + */ + ret = -EAGAIN; + break; + case HV_STATUS_INSUFFICIENT_MEMORY: + case HV_STATUS_INSUFFICIENT_BUFFERS: + ret = -ENOMEM; + break; + case HV_STATUS_SUCCESS: + return ret; + default: + pr_err("hv_post_msg() failed; error code:%d\n", ret); + return -EINVAL; + } + + retries++; + msleep(msec); + if (msec < 2048) + msec *= 2; + } + return ret; +} + +/* + * vmbus_set_event - Send an event notification to the parent + */ +int vmbus_set_event(struct vmbus_channel *channel) +{ + u32 child_relid = channel->offermsg.child_relid; + + if (!channel->is_dedicated_interrupt) { + /* Each u32 represents 32 channels */ + sync_set_bit(child_relid & 31, + (unsigned long *)vmbus_connection.send_int_page + + (child_relid >> 5)); + } + + return hv_signal_event(channel->sig_event); +} |