channel_mgmt.c

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/*
 * 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 <[email protected]>
 *   Hank Janssen  <[email protected]>
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/completion.h>
#include <linux/hyperv.h>

#include "hyperv_vmbus.h"

struct vmbus_channel_message_table_entry {
    enum vmbus_channel_message_type message_type;
    void (*message_handler)(struct vmbus_channel_message_header *msg);
};


void vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
                struct icmsg_negotiate *negop, u8 *buf,
                int max_fw_version, int max_srv_version)
{
    int icframe_vercnt;
    int icmsg_vercnt;
    int i;

    icmsghdrp->icmsgsize = 0x10;

    negop = (struct icmsg_negotiate *)&buf[
        sizeof(struct vmbuspipe_hdr) +
        sizeof(struct icmsg_hdr)];

    icframe_vercnt = negop->icframe_vercnt;
    icmsg_vercnt = negop->icmsg_vercnt;

    /*
     * Select the framework version number we will
     * support.
     */

    for (i = 0; i < negop->icframe_vercnt; i++) {
        if (negop->icversion_data[i].major <= max_fw_version)
            icframe_vercnt = negop->icversion_data[i].major;
    }

    for (i = negop->icframe_vercnt;
         (i < negop->icframe_vercnt + negop->icmsg_vercnt); i++) {
        if (negop->icversion_data[i].major <= max_srv_version)
            icmsg_vercnt = negop->icversion_data[i].major;
    }

    /*
     * Respond with the maximum framework and service
     * version numbers we can support.
     */
    negop->icframe_vercnt = 1;
    negop->icmsg_vercnt = 1;
    negop->icversion_data[0].major = icframe_vercnt;
    negop->icversion_data[0].minor = 0;
    negop->icversion_data[1].major = icmsg_vercnt;
    negop->icversion_data[1].minor = 0;
}

EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);

/*
 * alloc_channel - Allocate and initialize a vmbus channel object
 */
static struct vmbus_channel *alloc_channel(void)
{
    struct vmbus_channel *channel;

    channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
    if (!channel)
        return NULL;

    spin_lock_init(&channel->inbound_lock);

    channel->controlwq = create_workqueue("hv_vmbus_ctl");
    if (!channel->controlwq) {
        kfree(channel);
        return NULL;
    }

    return channel;
}

/*
 * release_hannel - Release the vmbus channel object itself
 */
static void release_channel(struct work_struct *work)
{
    struct vmbus_channel *channel = container_of(work,
                             struct vmbus_channel,
                             work);

    destroy_workqueue(channel->controlwq);

    kfree(channel);
}

/*
 * free_channel - Release the resources used by the vmbus channel object
 */
static void free_channel(struct vmbus_channel *channel)
{

    /*
     * We have to release the channel's workqueue/thread in the vmbus's
     * workqueue/thread context
     * ie we can't destroy ourselves.
     */
    INIT_WORK(&channel->work, release_channel);
    queue_work(vmbus_connection.work_queue, &channel->work);
}



/*
 * vmbus_process_rescind_offer -
 * Rescind the offer by initiating a device removal
 */
static void vmbus_process_rescind_offer(struct work_struct *work)
{
    struct vmbus_channel *channel = container_of(work,
                             struct vmbus_channel,
                             work);

    vmbus_device_unregister(channel->device_obj);
}

void vmbus_free_channels(void)
{
    struct vmbus_channel *channel;

    list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
        vmbus_device_unregister(channel->device_obj);
        kfree(channel->device_obj);
        free_channel(channel);
    }
}

/*
 * vmbus_process_offer - Process the offer by creating a channel/device
 * associated with this offer
 */
static void vmbus_process_offer(struct work_struct *work)
{
    struct vmbus_channel *newchannel = container_of(work,
                            struct vmbus_channel,
                            work);
    struct vmbus_channel *channel;
    bool fnew = true;
    int ret;
    unsigned long flags;

    /* The next possible work is rescind handling */
    INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);

    /* Make sure this is a new offer */
    spin_lock_irqsave(&vmbus_connection.channel_lock, flags);

    list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
        if (!uuid_le_cmp(channel->offermsg.offer.if_type,
            newchannel->offermsg.offer.if_type) &&
            !uuid_le_cmp(channel->offermsg.offer.if_instance,
                newchannel->offermsg.offer.if_instance)) {
            fnew = false;
            break;
        }
    }

    if (fnew)
        list_add_tail(&newchannel->listentry,
                  &vmbus_connection.chn_list);

    spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);

    if (!fnew) {
        free_channel(newchannel);
        return;
    }

    /*
     * Start the process of binding this offer to the driver
     * We need to set the DeviceObject field before calling
     * vmbus_child_dev_add()
     */
    newchannel->device_obj = vmbus_device_create(
        &newchannel->offermsg.offer.if_type,
        &newchannel->offermsg.offer.if_instance,
        newchannel);

    /*
     * Add the new device to the bus. This will kick off device-driver
     * binding which eventually invokes the device driver's AddDevice()
     * method.
     */
    ret = vmbus_device_register(newchannel->device_obj);
    if (ret != 0) {
        pr_err("unable to add child device object (relid %d)\n",
               newchannel->offermsg.child_relid);

        spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
        list_del(&newchannel->listentry);
        spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
        kfree(newchannel->device_obj);

        free_channel(newchannel);
    } else {
        /*
         * This state is used to indicate a successful open
         * so that when we do close the channel normally, we
         * can cleanup properly
         */
        newchannel->state = CHANNEL_OPEN_STATE;
    }
}

/*
 * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 *
 */
static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
{
    struct vmbus_channel_offer_channel *offer;
    struct vmbus_channel *newchannel;
    uuid_le *guidtype;
    uuid_le *guidinstance;

    offer = (struct vmbus_channel_offer_channel *)hdr;

    guidtype = &offer->offer.if_type;
    guidinstance = &offer->offer.if_instance;

    /* Allocate the channel object and save this offer. */
    newchannel = alloc_channel();
    if (!newchannel) {
        pr_err("Unable to allocate channel object\n");
        return;
    }

    memcpy(&newchannel->offermsg, offer,
           sizeof(struct vmbus_channel_offer_channel));
    newchannel->monitor_grp = (u8)offer->monitorid / 32;
    newchannel->monitor_bit = (u8)offer->monitorid % 32;

    INIT_WORK(&newchannel->work, vmbus_process_offer);
    queue_work(newchannel->controlwq, &newchannel->work);
}

/*
 * vmbus_onoffer_rescind - Rescind offer handler.
 *
 * We queue a work item to process this offer synchronously
 */
static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
{
    struct vmbus_channel_rescind_offer *rescind;
    struct vmbus_channel *channel;

    rescind = (struct vmbus_channel_rescind_offer *)hdr;
    channel = relid2channel(rescind->child_relid);

    if (channel == NULL)
        /* Just return here, no channel found */
        return;

    /* work is initialized for vmbus_process_rescind_offer() from
     * vmbus_process_offer() where the channel got created */
    queue_work(channel->controlwq, &channel->work);
}

/*
 * vmbus_onoffers_delivered -
 * This is invoked when all offers have been delivered.
 *
 * Nothing to do here.
 */
static void vmbus_onoffers_delivered(
            struct vmbus_channel_message_header *hdr)
{
}

/*
 * vmbus_onopen_result - Open result handler.
 *
 * This is invoked when we received a response to our channel open request.
 * Find the matching request, copy the response and signal the requesting
 * thread.
 */
static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
{
    struct vmbus_channel_open_result *result;
    struct vmbus_channel_msginfo *msginfo;
    struct vmbus_channel_message_header *requestheader;
    struct vmbus_channel_open_channel *openmsg;
    unsigned long flags;

    result = (struct vmbus_channel_open_result *)hdr;

    /*
     * Find the open msg, copy the result and signal/unblock the wait event
     */
    spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);

    list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
                msglistentry) {
        requestheader =
            (struct vmbus_channel_message_header *)msginfo->msg;

        if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
            openmsg =
            (struct vmbus_channel_open_channel *)msginfo->msg;
            if (openmsg->child_relid == result->child_relid &&
                openmsg->openid == result->openid) {
                memcpy(&msginfo->response.open_result,
                       result,
                       sizeof(
                    struct vmbus_channel_open_result));
                complete(&msginfo->waitevent);
                break;
            }
        }
    }
    spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
}

/*
 * vmbus_ongpadl_created - GPADL created handler.
 *
 * This is invoked when we received a response to our gpadl create request.
 * Find the matching request, copy the response and signal the requesting
 * thread.
 */
static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
{
    struct vmbus_channel_gpadl_created *gpadlcreated;
    struct vmbus_channel_msginfo *msginfo;
    struct vmbus_channel_message_header *requestheader;
    struct vmbus_channel_gpadl_header *gpadlheader;
    unsigned long flags;

    gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;

    /*
     * Find the establish msg, copy the result and signal/unblock the wait
     * event
     */
    spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);

    list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
                msglistentry) {
        requestheader =
            (struct vmbus_channel_message_header *)msginfo->msg;

        if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
            gpadlheader =
            (struct vmbus_channel_gpadl_header *)requestheader;

            if ((gpadlcreated->child_relid ==
                 gpadlheader->child_relid) &&
                (gpadlcreated->gpadl == gpadlheader->gpadl)) {
                memcpy(&msginfo->response.gpadl_created,
                       gpadlcreated,
                       sizeof(
                    struct vmbus_channel_gpadl_created));
                complete(&msginfo->waitevent);
                break;
            }
        }
    }
    spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
}

/*
 * vmbus_ongpadl_torndown - GPADL torndown handler.
 *
 * This is invoked when we received a response to our gpadl teardown request.
 * Find the matching request, copy the response and signal the requesting
 * thread.
 */
static void vmbus_ongpadl_torndown(
            struct vmbus_channel_message_header *hdr)
{
    struct vmbus_channel_gpadl_torndown *gpadl_torndown;
    struct vmbus_channel_msginfo *msginfo;
    struct vmbus_channel_message_header *requestheader;
    struct vmbus_channel_gpadl_teardown *gpadl_teardown;
    unsigned long flags;

    gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;

    /*
     * Find the open msg, copy the result and signal/unblock the wait event
     */
    spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);

    list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
                msglistentry) {
        requestheader =
            (struct vmbus_channel_message_header *)msginfo->msg;

        if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
            gpadl_teardown =
            (struct vmbus_channel_gpadl_teardown *)requestheader;

            if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
                memcpy(&msginfo->response.gpadl_torndown,
                       gpadl_torndown,
                       sizeof(
                    struct vmbus_channel_gpadl_torndown));
                complete(&msginfo->waitevent);
                break;
            }
        }
    }
    spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
}

/*
 * vmbus_onversion_response - Version response handler
 *
 * This is invoked when we received a response to our initiate contact request.
 * Find the matching request, copy the response and signal the requesting
 * thread.
 */
static void vmbus_onversion_response(
        struct vmbus_channel_message_header *hdr)
{
    struct vmbus_channel_msginfo *msginfo;
    struct vmbus_channel_message_header *requestheader;
    struct vmbus_channel_initiate_contact *initiate;
    struct vmbus_channel_version_response *version_response;
    unsigned long flags;

    version_response = (struct vmbus_channel_version_response *)hdr;
    spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);

    list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
                msglistentry) {
        requestheader =
            (struct vmbus_channel_message_header *)msginfo->msg;

        if (requestheader->msgtype ==
            CHANNELMSG_INITIATE_CONTACT) {
            initiate =
            (struct vmbus_channel_initiate_contact *)requestheader;
            memcpy(&msginfo->response.version_response,
                  version_response,
                  sizeof(struct vmbus_channel_version_response));
            complete(&msginfo->waitevent);
        }
    }
    spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
}

/* Channel message dispatch table */
static struct vmbus_channel_message_table_entry
    channel_message_table[CHANNELMSG_COUNT] = {
    {CHANNELMSG_INVALID,            NULL},
    {CHANNELMSG_OFFERCHANNEL,       vmbus_onoffer},
    {CHANNELMSG_RESCIND_CHANNELOFFER,   vmbus_onoffer_rescind},
    {CHANNELMSG_REQUESTOFFERS,      NULL},
    {CHANNELMSG_ALLOFFERS_DELIVERED,    vmbus_onoffers_delivered},
    {CHANNELMSG_OPENCHANNEL,        NULL},
    {CHANNELMSG_OPENCHANNEL_RESULT, vmbus_onopen_result},
    {CHANNELMSG_CLOSECHANNEL,       NULL},
    {CHANNELMSG_GPADL_HEADER,       NULL},
    {CHANNELMSG_GPADL_BODY,     NULL},
    {CHANNELMSG_GPADL_CREATED,      vmbus_ongpadl_created},
    {CHANNELMSG_GPADL_TEARDOWN,     NULL},
    {CHANNELMSG_GPADL_TORNDOWN,     vmbus_ongpadl_torndown},
    {CHANNELMSG_RELID_RELEASED,     NULL},
    {CHANNELMSG_INITIATE_CONTACT,       NULL},
    {CHANNELMSG_VERSION_RESPONSE,       vmbus_onversion_response},
    {CHANNELMSG_UNLOAD,         NULL},
};

/*
 * vmbus_onmessage - Handler for channel protocol messages.
 *
 * This is invoked in the vmbus worker thread context.
 */
void vmbus_onmessage(void *context)
{
    struct hv_message *msg = context;
    struct vmbus_channel_message_header *hdr;
    int size;

    hdr = (struct vmbus_channel_message_header *)msg->u.payload;
    size = msg->header.payload_size;

    if (hdr->msgtype >= CHANNELMSG_COUNT) {
        pr_err("Received invalid channel message type %d size %d\n",
               hdr->msgtype, size);
        print_hex_dump_bytes("", DUMP_PREFIX_NONE,
                     (unsigned char *)msg->u.payload, size);
        return;
    }

    if (channel_message_table[hdr->msgtype].message_handler)
        channel_message_table[hdr->msgtype].message_handler(hdr);
    else
        pr_err("Unhandled channel message type %d\n", hdr->msgtype);
}

/*
 * vmbus_request_offers - Send a request to get all our pending offers.
 */
int vmbus_request_offers(void)
{
    struct vmbus_channel_message_header *msg;
    struct vmbus_channel_msginfo *msginfo;
    int ret, t;

    msginfo = kmalloc(sizeof(*msginfo) +
              sizeof(struct vmbus_channel_message_header),
              GFP_KERNEL);
    if (!msginfo)
        return -ENOMEM;

    init_completion(&msginfo->waitevent);

    msg = (struct vmbus_channel_message_header *)msginfo->msg;

    msg->msgtype = CHANNELMSG_REQUESTOFFERS;


    ret = vmbus_post_msg(msg,
                   sizeof(struct vmbus_channel_message_header));
    if (ret != 0) {
        pr_err("Unable to request offers - %d\n", ret);

        goto cleanup;
    }

    t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
    if (t == 0) {
        ret = -ETIMEDOUT;
        goto cleanup;
    }



cleanup:
    kfree(msginfo);

    return ret;
}

/* eof */