Staging: hv: move hyperv code out of staging directory

After many years wandering the desert, it is finally time for the
Microsoft HyperV code to move out of the staging directory.  Or at least
the core hyperv bus code, and the utility driver, the rest still have
some review to get through by the various subsystem maintainers.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>

1 files changed, 815 insertions, 0 deletions

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
new file mode 100644
index 000000000000..406537420fff
--- /dev/null
+++ b/drivers/hv/channel.c
@@ -0,0 +1,815 @@
+/*
+ * 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/mm.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/hyperv.h>
+
+#include "hyperv_vmbus.h"
+
+#define NUM_PAGES_SPANNED(addr, len) \
+((PAGE_ALIGN(addr + len) >> PAGE_SHIFT) - (addr >> PAGE_SHIFT))
+
+/* Internal routines */
+static int create_gpadl_header(
+        void *kbuffer,  /* must be phys and virt contiguous */
+        u32 size,       /* page-size multiple */
+        struct vmbus_channel_msginfo **msginfo,
+        u32 *messagecount);
+static void vmbus_setevent(struct vmbus_channel *channel);
+
+/*
+ * vmbus_setevent- Trigger an event notification on the specified
+ * channel.
+ */
+static void vmbus_setevent(struct vmbus_channel *channel)
+{
+        struct hv_monitor_page *monitorpage;
+
+        if (channel->offermsg.monitor_allocated) {
+                /* Each u32 represents 32 channels */
+                sync_set_bit(channel->offermsg.child_relid & 31,
+                        (unsigned long *) vmbus_connection.send_int_page +
+                        (channel->offermsg.child_relid >> 5));
+
+                monitorpage = vmbus_connection.monitor_pages;
+                monitorpage++; /* Get the child to parent monitor page */
+
+                sync_set_bit(channel->monitor_bit,
+                        (unsigned long *)&monitorpage->trigger_group
+                                        [channel->monitor_grp].pending);
+
+        } else {
+                vmbus_set_event(channel->offermsg.child_relid);
+        }
+}
+
+/*
+ * vmbus_get_debug_info -Retrieve various channel debug info
+ */
+void vmbus_get_debug_info(struct vmbus_channel *channel,
+                              struct vmbus_channel_debug_info *debuginfo)
+{
+        struct hv_monitor_page *monitorpage;
+        u8 monitor_group = (u8)channel->offermsg.monitorid / 32;
+        u8 monitor_offset = (u8)channel->offermsg.monitorid % 32;
+
+        debuginfo->relid = channel->offermsg.child_relid;
+        debuginfo->state = channel->state;
+        memcpy(&debuginfo->interfacetype,
+               &channel->offermsg.offer.if_type, sizeof(uuid_le));
+        memcpy(&debuginfo->interface_instance,
+               &channel->offermsg.offer.if_instance,
+               sizeof(uuid_le));
+
+        monitorpage = (struct hv_monitor_page *)vmbus_connection.monitor_pages;
+
+        debuginfo->monitorid = channel->offermsg.monitorid;
+
+        debuginfo->servermonitor_pending =
+                        monitorpage->trigger_group[monitor_group].pending;
+        debuginfo->servermonitor_latency =
+                        monitorpage->latency[monitor_group][monitor_offset];
+        debuginfo->servermonitor_connectionid =
+                        monitorpage->parameter[monitor_group]
+                                        [monitor_offset].connectionid.u.id;
+
+        monitorpage++;
+
+        debuginfo->clientmonitor_pending =
+                        monitorpage->trigger_group[monitor_group].pending;
+        debuginfo->clientmonitor_latency =
+                        monitorpage->latency[monitor_group][monitor_offset];
+        debuginfo->clientmonitor_connectionid =
+                        monitorpage->parameter[monitor_group]
+                                        [monitor_offset].connectionid.u.id;
+
+        hv_ringbuffer_get_debuginfo(&channel->inbound, &debuginfo->inbound);
+        hv_ringbuffer_get_debuginfo(&channel->outbound, &debuginfo->outbound);
+}
+
+/*
+ * vmbus_open - Open the specified channel.
+ */
+int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
+                     u32 recv_ringbuffer_size, void *userdata, u32 userdatalen,
+                     void (*onchannelcallback)(void *context), void *context)
+{
+        struct vmbus_channel_open_channel *open_msg;
+        struct vmbus_channel_msginfo *open_info = NULL;
+        void *in, *out;
+        unsigned long flags;
+        int ret, t, err = 0;
+
+        newchannel->onchannel_callback = onchannelcallback;
+        newchannel->channel_callback_context = context;
+
+        /* Allocate the ring buffer */
+        out = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
+                get_order(send_ringbuffer_size + recv_ringbuffer_size));
+
+        if (!out)
+                return -ENOMEM;
+
+
+        in = (void *)((unsigned long)out + send_ringbuffer_size);
+
+        newchannel->ringbuffer_pages = out;
+        newchannel->ringbuffer_pagecount = (send_ringbuffer_size +
+                                           recv_ringbuffer_size) >> PAGE_SHIFT;
+
+        ret = hv_ringbuffer_init(
+                &newchannel->outbound, out, send_ringbuffer_size);
+
+        if (ret != 0) {
+                err = ret;
+                goto errorout;
+        }
+
+        ret = hv_ringbuffer_init(
+                &newchannel->inbound, in, recv_ringbuffer_size);
+        if (ret != 0) {
+                err = ret;
+                goto errorout;
+        }
+
+
+        /* Establish the gpadl for the ring buffer */
+        newchannel->ringbuffer_gpadlhandle = 0;
+
+        ret = vmbus_establish_gpadl(newchannel,
+                                         newchannel->outbound.ring_buffer,
+                                         send_ringbuffer_size +
+                                         recv_ringbuffer_size,
+                                         &newchannel->ringbuffer_gpadlhandle);
+
+        if (ret != 0) {
+                err = ret;
+                goto errorout;
+        }
+
+        /* Create and init the channel open message */
+        open_info = kmalloc(sizeof(*open_info) +
+                           sizeof(struct vmbus_channel_open_channel),
+                           GFP_KERNEL);
+        if (!open_info) {
+                err = -ENOMEM;
+                goto errorout;
+        }
+
+        init_completion(&open_info->waitevent);
+
+        open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
+        open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
+        open_msg->openid = newchannel->offermsg.child_relid;
+        open_msg->child_relid = newchannel->offermsg.child_relid;
+        open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
+        open_msg->downstream_ringbuffer_pageoffset = send_ringbuffer_size >>
+                                                  PAGE_SHIFT;
+        open_msg->server_contextarea_gpadlhandle = 0;
+
+        if (userdatalen > MAX_USER_DEFINED_BYTES) {
+                err = -EINVAL;
+                goto errorout;
+        }
+
+        if (userdatalen)
+                memcpy(open_msg->userdata, userdata, userdatalen);
+
+        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
+        list_add_tail(&open_info->msglistentry,
+                      &vmbus_connection.chn_msg_list);
+        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
+
+        ret = vmbus_post_msg(open_msg,
+                               sizeof(struct vmbus_channel_open_channel));
+
+        if (ret != 0)
+                goto cleanup;
+
+        t = wait_for_completion_timeout(&open_info->waitevent, 5*HZ);
+        if (t == 0) {
+                err = -ETIMEDOUT;
+                goto errorout;
+        }
+
+
+        if (open_info->response.open_result.status)
+                err = open_info->response.open_result.status;
+
+cleanup:
+        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
+        list_del(&open_info->msglistentry);
+        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
+
+        kfree(open_info);
+        return err;
+
+errorout:
+        hv_ringbuffer_cleanup(&newchannel->outbound);
+        hv_ringbuffer_cleanup(&newchannel->inbound);
+        free_pages((unsigned long)out,
+                get_order(send_ringbuffer_size + recv_ringbuffer_size));
+        kfree(open_info);
+        return err;
+}
+EXPORT_SYMBOL_GPL(vmbus_open);
+
+/*
+ * create_gpadl_header - Creates a gpadl for the specified buffer
+ */
+static int create_gpadl_header(void *kbuffer, u32 size,
+                                         struct vmbus_channel_msginfo **msginfo,
+                                         u32 *messagecount)
+{
+        int i;
+        int pagecount;
+        unsigned long long pfn;
+        struct vmbus_channel_gpadl_header *gpadl_header;
+        struct vmbus_channel_gpadl_body *gpadl_body;
+        struct vmbus_channel_msginfo *msgheader;
+        struct vmbus_channel_msginfo *msgbody = NULL;
+        u32 msgsize;
+
+        int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
+
+        pagecount = size >> PAGE_SHIFT;
+        pfn = virt_to_phys(kbuffer) >> PAGE_SHIFT;
+
+        /* do we need a gpadl body msg */
+        pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
+                  sizeof(struct vmbus_channel_gpadl_header) -
+                  sizeof(struct gpa_range);
+        pfncount = pfnsize / sizeof(u64);
+
+        if (pagecount > pfncount) {
+                /* we need a gpadl body */
+                /* fill in the header */
+                msgsize = sizeof(struct vmbus_channel_msginfo) +
+                          sizeof(struct vmbus_channel_gpadl_header) +
+                          sizeof(struct gpa_range) + pfncount * sizeof(u64);
+                msgheader =  kzalloc(msgsize, GFP_KERNEL);
+                if (!msgheader)
+                        goto nomem;
+
+                INIT_LIST_HEAD(&msgheader->submsglist);
+                msgheader->msgsize = msgsize;
+
+                gpadl_header = (struct vmbus_channel_gpadl_header *)
+                        msgheader->msg;
+                gpadl_header->rangecount = 1;
+                gpadl_header->range_buflen = sizeof(struct gpa_range) +
+                                         pagecount * sizeof(u64);
+                gpadl_header->range[0].byte_offset = 0;
+                gpadl_header->range[0].byte_count = size;
+                for (i = 0; i < pfncount; i++)
+                        gpadl_header->range[0].pfn_array[i] = pfn+i;
+                *msginfo = msgheader;
+                *messagecount = 1;
+
+                pfnsum = pfncount;
+                pfnleft = pagecount - pfncount;
+
+                /* how many pfns can we fit */
+                pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
+                          sizeof(struct vmbus_channel_gpadl_body);
+                pfncount = pfnsize / sizeof(u64);
+
+                /* fill in the body */
+                while (pfnleft) {
+                        if (pfnleft > pfncount)
+                                pfncurr = pfncount;
+                        else
+                                pfncurr = pfnleft;
+
+                        msgsize = sizeof(struct vmbus_channel_msginfo) +
+                                  sizeof(struct vmbus_channel_gpadl_body) +
+                                  pfncurr * sizeof(u64);
+                        msgbody = kzalloc(msgsize, GFP_KERNEL);
+
+                        if (!msgbody) {
+                                struct vmbus_channel_msginfo *pos = NULL;
+                                struct vmbus_channel_msginfo *tmp = NULL;
+                                /*
+                                 * Free up all the allocated messages.
+                                 */
+                                list_for_each_entry_safe(pos, tmp,
+                                        &msgheader->submsglist,
+                                        msglistentry) {
+
+                                        list_del(&pos->msglistentry);
+                                        kfree(pos);
+                                }
+
+                                goto nomem;
+                        }
+
+                        msgbody->msgsize = msgsize;
+                        (*messagecount)++;
+                        gpadl_body =
+                                (struct vmbus_channel_gpadl_body *)msgbody->msg;
+
+                        /*
+                         * Gpadl is u32 and we are using a pointer which could
+                         * be 64-bit
+                         * This is governed by the guest/host protocol and
+                         * so the hypervisor gurantees that this is ok.
+                         */
+                        for (i = 0; i < pfncurr; i++)
+                                gpadl_body->pfn[i] = pfn + pfnsum + i;
+
+                        /* add to msg header */
+                        list_add_tail(&msgbody->msglistentry,
+                                      &msgheader->submsglist);
+                        pfnsum += pfncurr;
+                        pfnleft -= pfncurr;
+                }
+        } else {
+                /* everything fits in a header */
+                msgsize = sizeof(struct vmbus_channel_msginfo) +
+                          sizeof(struct vmbus_channel_gpadl_header) +
+                          sizeof(struct gpa_range) + pagecount * sizeof(u64);
+                msgheader = kzalloc(msgsize, GFP_KERNEL);
+                if (msgheader == NULL)
+                        goto nomem;
+                msgheader->msgsize = msgsize;
+
+                gpadl_header = (struct vmbus_channel_gpadl_header *)
+                        msgheader->msg;
+                gpadl_header->rangecount = 1;
+                gpadl_header->range_buflen = sizeof(struct gpa_range) +
+                                         pagecount * sizeof(u64);
+                gpadl_header->range[0].byte_offset = 0;
+                gpadl_header->range[0].byte_count = size;
+                for (i = 0; i < pagecount; i++)
+                        gpadl_header->range[0].pfn_array[i] = pfn+i;
+
+                *msginfo = msgheader;
+                *messagecount = 1;
+        }
+
+        return 0;
+nomem:
+        kfree(msgheader);
+        kfree(msgbody);
+        return -ENOMEM;
+}
+
+/*
+ * vmbus_establish_gpadl - Estabish a GPADL for the specified buffer
+ *
+ * @channel: a channel
+ * @kbuffer: from kmalloc
+ * @size: page-size multiple
+ * @gpadl_handle: some funky thing
+ */
+int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
+                               u32 size, u32 *gpadl_handle)
+{
+        struct vmbus_channel_gpadl_header *gpadlmsg;
+        struct vmbus_channel_gpadl_body *gpadl_body;
+        struct vmbus_channel_msginfo *msginfo = NULL;
+        struct vmbus_channel_msginfo *submsginfo;
+        u32 msgcount;
+        struct list_head *curr;
+        u32 next_gpadl_handle;
+        unsigned long flags;
+        int ret = 0;
+        int t;
+
+        next_gpadl_handle = atomic_read(&vmbus_connection.next_gpadl_handle);
+        atomic_inc(&vmbus_connection.next_gpadl_handle);
+
+        ret = create_gpadl_header(kbuffer, size, &msginfo, &msgcount);
+        if (ret)
+                return ret;
+
+        init_completion(&msginfo->waitevent);
+
+        gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
+        gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
+        gpadlmsg->child_relid = channel->offermsg.child_relid;
+        gpadlmsg->gpadl = next_gpadl_handle;
+
+
+        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(gpadlmsg, msginfo->msgsize -
+                               sizeof(*msginfo));
+        if (ret != 0)
+                goto cleanup;
+
+        if (msgcount > 1) {
+                list_for_each(curr, &msginfo->submsglist) {
+
+                        submsginfo = (struct vmbus_channel_msginfo *)curr;
+                        gpadl_body =
+                             (struct vmbus_channel_gpadl_body *)submsginfo->msg;
+
+                        gpadl_body->header.msgtype =
+                                CHANNELMSG_GPADL_BODY;
+                        gpadl_body->gpadl = next_gpadl_handle;
+
+                        ret = vmbus_post_msg(gpadl_body,
+                                               submsginfo->msgsize -
+                                               sizeof(*submsginfo));
+                        if (ret != 0)
+                                goto cleanup;
+
+                }
+        }
+        t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
+        BUG_ON(t == 0);
+
+
+        /* At this point, we received the gpadl created msg */
+        *gpadl_handle = gpadlmsg->gpadl;
+
+cleanup:
+        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
+        list_del(&msginfo->msglistentry);
+        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
+
+        kfree(msginfo);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
+
+/*
+ * vmbus_teardown_gpadl -Teardown the specified GPADL handle
+ */
+int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
+{
+        struct vmbus_channel_gpadl_teardown *msg;
+        struct vmbus_channel_msginfo *info;
+        unsigned long flags;
+        int ret, t;
+
+        info = kmalloc(sizeof(*info) +
+                       sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
+        if (!info)
+                return -ENOMEM;
+
+        init_completion(&info->waitevent);
+
+        msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
+
+        msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
+        msg->child_relid = channel->offermsg.child_relid;
+        msg->gpadl = gpadl_handle;
+
+        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
+        list_add_tail(&info->msglistentry,
+                      &vmbus_connection.chn_msg_list);
+        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
+        ret = vmbus_post_msg(msg,
+                               sizeof(struct vmbus_channel_gpadl_teardown));
+
+        BUG_ON(ret != 0);
+        t = wait_for_completion_timeout(&info->waitevent, 5*HZ);
+        BUG_ON(t == 0);
+
+        /* Received a torndown response */
+        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
+        list_del(&info->msglistentry);
+        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
+
+        kfree(info);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
+
+/*
+ * vmbus_close - Close the specified channel
+ */
+void vmbus_close(struct vmbus_channel *channel)
+{
+        struct vmbus_channel_close_channel *msg;
+        int ret;
+        unsigned long flags;
+
+        /* Stop callback and cancel the timer asap */
+        spin_lock_irqsave(&channel->inbound_lock, flags);
+        channel->onchannel_callback = NULL;
+        spin_unlock_irqrestore(&channel->inbound_lock, flags);
+
+        /* Send a closing message */
+
+        msg = &channel->close_msg.msg;
+
+        msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
+        msg->child_relid = channel->offermsg.child_relid;
+
+        ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel));
+
+        BUG_ON(ret != 0);
+        /* Tear down the gpadl for the channel's ring buffer */
+        if (channel->ringbuffer_gpadlhandle)
+                vmbus_teardown_gpadl(channel,
+                                          channel->ringbuffer_gpadlhandle);
+
+        /* Cleanup the ring buffers for this channel */
+        hv_ringbuffer_cleanup(&channel->outbound);
+        hv_ringbuffer_cleanup(&channel->inbound);
+
+        free_pages((unsigned long)channel->ringbuffer_pages,
+                get_order(channel->ringbuffer_pagecount * PAGE_SIZE));
+
+
+}
+EXPORT_SYMBOL_GPL(vmbus_close);
+
+/**
+ * vmbus_sendpacket() - Send the specified buffer on the given channel
+ * @channel: Pointer to vmbus_channel structure.
+ * @buffer: Pointer to the buffer you want to receive the data into.
+ * @bufferlen: Maximum size of what the the buffer will hold
+ * @requestid: Identifier of the request
+ * @type: Type of packet that is being send e.g. negotiate, time
+ * packet etc.
+ *
+ * Sends data in @buffer directly to hyper-v via the vmbus
+ * This will send the data unparsed to hyper-v.
+ *
+ * Mainly used by Hyper-V drivers.
+ */
+int vmbus_sendpacket(struct vmbus_channel *channel, const void *buffer,
+                           u32 bufferlen, u64 requestid,
+                           enum vmbus_packet_type type, u32 flags)
+{
+        struct vmpacket_descriptor desc;
+        u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
+        u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
+        struct scatterlist bufferlist[3];
+        u64 aligned_data = 0;
+        int ret;
+
+
+        /* Setup the descriptor */
+        desc.type = type; /* VmbusPacketTypeDataInBand; */
+        desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
+        /* in 8-bytes granularity */
+        desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
+        desc.len8 = (u16)(packetlen_aligned >> 3);
+        desc.trans_id = requestid;
+
+        sg_init_table(bufferlist, 3);
+        sg_set_buf(&bufferlist[0], &desc, sizeof(struct vmpacket_descriptor));
+        sg_set_buf(&bufferlist[1], buffer, bufferlen);
+        sg_set_buf(&bufferlist[2], &aligned_data,
+                   packetlen_aligned - packetlen);
+
+        ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3);
+
+        if (ret == 0 && !hv_get_ringbuffer_interrupt_mask(&channel->outbound))
+                vmbus_setevent(channel);
+
+        return ret;
+}
+EXPORT_SYMBOL(vmbus_sendpacket);
+
+/*
+ * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
+ * packets using a GPADL Direct packet type.
+ */
+int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
+                                     struct hv_page_buffer pagebuffers[],
+                                     u32 pagecount, void *buffer, u32 bufferlen,
+                                     u64 requestid)
+{
+        int ret;
+        int i;
+        struct vmbus_channel_packet_page_buffer desc;
+        u32 descsize;
+        u32 packetlen;
+        u32 packetlen_aligned;
+        struct scatterlist bufferlist[3];
+        u64 aligned_data = 0;
+
+        if (pagecount > MAX_PAGE_BUFFER_COUNT)
+                return -EINVAL;
+
+
+        /*
+         * Adjust the size down since vmbus_channel_packet_page_buffer is the
+         * largest size we support
+         */
+        descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
+                          ((MAX_PAGE_BUFFER_COUNT - pagecount) *
+                          sizeof(struct hv_page_buffer));
+        packetlen = descsize + bufferlen;
+        packetlen_aligned = ALIGN(packetlen, sizeof(u64));
+
+        /* Setup the descriptor */
+        desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
+        desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
+        desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
+        desc.length8 = (u16)(packetlen_aligned >> 3);
+        desc.transactionid = requestid;
+        desc.rangecount = pagecount;
+
+        for (i = 0; i < pagecount; i++) {
+                desc.range[i].len = pagebuffers[i].len;
+                desc.range[i].offset = pagebuffers[i].offset;
+                desc.range[i].pfn        = pagebuffers[i].pfn;
+        }
+
+        sg_init_table(bufferlist, 3);
+        sg_set_buf(&bufferlist[0], &desc, descsize);
+        sg_set_buf(&bufferlist[1], buffer, bufferlen);
+        sg_set_buf(&bufferlist[2], &aligned_data,
+                packetlen_aligned - packetlen);
+
+        ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3);
+
+        if (ret == 0 && !hv_get_ringbuffer_interrupt_mask(&channel->outbound))
+                vmbus_setevent(channel);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
+
+/*
+ * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
+ * using a GPADL Direct packet type.
+ */
+int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
+                                struct hv_multipage_buffer *multi_pagebuffer,
+                                void *buffer, u32 bufferlen, u64 requestid)
+{
+        int ret;
+        struct vmbus_channel_packet_multipage_buffer desc;
+        u32 descsize;
+        u32 packetlen;
+        u32 packetlen_aligned;
+        struct scatterlist bufferlist[3];
+        u64 aligned_data = 0;
+        u32 pfncount = NUM_PAGES_SPANNED(multi_pagebuffer->offset,
+                                         multi_pagebuffer->len);
+
+
+        if ((pfncount < 0) || (pfncount > MAX_MULTIPAGE_BUFFER_COUNT))
+                return -EINVAL;
+
+        /*
+         * Adjust the size down since vmbus_channel_packet_multipage_buffer is
+         * the largest size we support
+         */
+        descsize = sizeof(struct vmbus_channel_packet_multipage_buffer) -
+                          ((MAX_MULTIPAGE_BUFFER_COUNT - pfncount) *
+                          sizeof(u64));
+        packetlen = descsize + bufferlen;
+        packetlen_aligned = ALIGN(packetlen, sizeof(u64));
+
+
+        /* Setup the descriptor */
+        desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
+        desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
+        desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
+        desc.length8 = (u16)(packetlen_aligned >> 3);
+        desc.transactionid = requestid;
+        desc.rangecount = 1;
+
+        desc.range.len = multi_pagebuffer->len;
+        desc.range.offset = multi_pagebuffer->offset;
+
+        memcpy(desc.range.pfn_array, multi_pagebuffer->pfn_array,
+               pfncount * sizeof(u64));
+
+        sg_init_table(bufferlist, 3);
+        sg_set_buf(&bufferlist[0], &desc, descsize);
+        sg_set_buf(&bufferlist[1], buffer, bufferlen);
+        sg_set_buf(&bufferlist[2], &aligned_data,
+                packetlen_aligned - packetlen);
+
+        ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3);
+
+        if (ret == 0 && !hv_get_ringbuffer_interrupt_mask(&channel->outbound))
+                vmbus_setevent(channel);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer);
+
+/**
+ * vmbus_recvpacket() - Retrieve the user packet on the specified channel
+ * @channel: Pointer to vmbus_channel structure.
+ * @buffer: Pointer to the buffer you want to receive the data into.
+ * @bufferlen: Maximum size of what the the buffer will hold
+ * @buffer_actual_len: The actual size of the data after it was received
+ * @requestid: Identifier of the request
+ *
+ * Receives directly from the hyper-v vmbus and puts the data it received
+ * into Buffer. This will receive the data unparsed from hyper-v.
+ *
+ * Mainly used by Hyper-V drivers.
+ */
+int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
+                        u32 bufferlen, u32 *buffer_actual_len, u64 *requestid)
+{
+        struct vmpacket_descriptor desc;
+        u32 packetlen;
+        u32 userlen;
+        int ret;
+
+        *buffer_actual_len = 0;
+        *requestid = 0;
+
+
+        ret = hv_ringbuffer_peek(&channel->inbound, &desc,
+                             sizeof(struct vmpacket_descriptor));
+        if (ret != 0)
+                return 0;
+
+        packetlen = desc.len8 << 3;
+        userlen = packetlen - (desc.offset8 << 3);
+
+        *buffer_actual_len = userlen;
+
+        if (userlen > bufferlen) {
+
+                pr_err("Buffer too small - got %d needs %d\n",
+                           bufferlen, userlen);
+                return -ETOOSMALL;
+        }
+
+        *requestid = desc.trans_id;
+
+        /* Copy over the packet to the user buffer */
+        ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen,
+                             (desc.offset8 << 3));
+
+
+        return 0;
+}
+EXPORT_SYMBOL(vmbus_recvpacket);
+
+/*
+ * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
+ */
+int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
+                              u32 bufferlen, u32 *buffer_actual_len,
+                              u64 *requestid)
+{
+        struct vmpacket_descriptor desc;
+        u32 packetlen;
+        u32 userlen;
+        int ret;
+
+        *buffer_actual_len = 0;
+        *requestid = 0;
+
+
+        ret = hv_ringbuffer_peek(&channel->inbound, &desc,
+                             sizeof(struct vmpacket_descriptor));
+        if (ret != 0)
+                return 0;
+
+
+        packetlen = desc.len8 << 3;
+        userlen = packetlen - (desc.offset8 << 3);
+
+        *buffer_actual_len = packetlen;
+
+        if (packetlen > bufferlen) {
+                pr_err("Buffer too small - needed %d bytes but "
+                        "got space for only %d bytes\n",
+                        packetlen, bufferlen);
+                return -ENOBUFS;
+        }
+
+        *requestid = desc.trans_id;
+
+        /* Copy over the entire packet to the user buffer */
+        ret = hv_ringbuffer_read(&channel->inbound, buffer, packetlen, 0);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);