2 * Copyright (c) 2009, Microsoft Corporation.
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms and conditions of the GNU General Public License,
6 * version 2, as published by the Free Software Foundation.
8 * This program is distributed in the hope it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * You should have received a copy of the GNU General Public License along with
14 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
15 * Place - Suite 330, Boston, MA 02111-1307 USA.
18 * Haiyang Zhang <haiyangz@microsoft.com>
19 * Hank Janssen <hjanssen@microsoft.com>
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 #include <linux/kernel.h>
24 #include <linux/sched.h>
25 #include <linux/wait.h>
27 #include <linux/slab.h>
28 #include <linux/module.h>
29 #include <linux/hyperv.h>
31 #include "hyperv_vmbus.h"
33 #define NUM_PAGES_SPANNED(addr, len) \
34 ((PAGE_ALIGN(addr + len) >> PAGE_SHIFT) - (addr >> PAGE_SHIFT))
36 /* Internal routines */
37 static int create_gpadl_header(
38 void *kbuffer, /* must be phys and virt contiguous */
39 u32 size, /* page-size multiple */
40 struct vmbus_channel_msginfo **msginfo,
42 static void vmbus_setevent(struct vmbus_channel *channel);
45 * vmbus_setevent- Trigger an event notification on the specified
48 static void vmbus_setevent(struct vmbus_channel *channel)
50 struct hv_monitor_page *monitorpage;
52 if (channel->offermsg.monitor_allocated) {
53 /* Each u32 represents 32 channels */
54 sync_set_bit(channel->offermsg.child_relid & 31,
55 (unsigned long *) vmbus_connection.send_int_page +
56 (channel->offermsg.child_relid >> 5));
58 monitorpage = vmbus_connection.monitor_pages;
59 monitorpage++; /* Get the child to parent monitor page */
61 sync_set_bit(channel->monitor_bit,
62 (unsigned long *)&monitorpage->trigger_group
63 [channel->monitor_grp].pending);
66 vmbus_set_event(channel->offermsg.child_relid);
71 * vmbus_get_debug_info -Retrieve various channel debug info
73 void vmbus_get_debug_info(struct vmbus_channel *channel,
74 struct vmbus_channel_debug_info *debuginfo)
76 struct hv_monitor_page *monitorpage;
77 u8 monitor_group = (u8)channel->offermsg.monitorid / 32;
78 u8 monitor_offset = (u8)channel->offermsg.monitorid % 32;
80 debuginfo->relid = channel->offermsg.child_relid;
81 debuginfo->state = channel->state;
82 memcpy(&debuginfo->interfacetype,
83 &channel->offermsg.offer.if_type, sizeof(uuid_le));
84 memcpy(&debuginfo->interface_instance,
85 &channel->offermsg.offer.if_instance,
88 monitorpage = (struct hv_monitor_page *)vmbus_connection.monitor_pages;
90 debuginfo->monitorid = channel->offermsg.monitorid;
92 debuginfo->servermonitor_pending =
93 monitorpage->trigger_group[monitor_group].pending;
94 debuginfo->servermonitor_latency =
95 monitorpage->latency[monitor_group][monitor_offset];
96 debuginfo->servermonitor_connectionid =
97 monitorpage->parameter[monitor_group]
98 [monitor_offset].connectionid.u.id;
102 debuginfo->clientmonitor_pending =
103 monitorpage->trigger_group[monitor_group].pending;
104 debuginfo->clientmonitor_latency =
105 monitorpage->latency[monitor_group][monitor_offset];
106 debuginfo->clientmonitor_connectionid =
107 monitorpage->parameter[monitor_group]
108 [monitor_offset].connectionid.u.id;
110 hv_ringbuffer_get_debuginfo(&channel->inbound, &debuginfo->inbound);
111 hv_ringbuffer_get_debuginfo(&channel->outbound, &debuginfo->outbound);
115 * vmbus_open - Open the specified channel.
117 int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
118 u32 recv_ringbuffer_size, void *userdata, u32 userdatalen,
119 void (*onchannelcallback)(void *context), void *context)
121 struct vmbus_channel_open_channel *open_msg;
122 struct vmbus_channel_msginfo *open_info = NULL;
127 newchannel->onchannel_callback = onchannelcallback;
128 newchannel->channel_callback_context = context;
130 /* Allocate the ring buffer */
131 out = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
132 get_order(send_ringbuffer_size + recv_ringbuffer_size));
138 in = (void *)((unsigned long)out + send_ringbuffer_size);
140 newchannel->ringbuffer_pages = out;
141 newchannel->ringbuffer_pagecount = (send_ringbuffer_size +
142 recv_ringbuffer_size) >> PAGE_SHIFT;
144 ret = hv_ringbuffer_init(
145 &newchannel->outbound, out, send_ringbuffer_size);
152 ret = hv_ringbuffer_init(
153 &newchannel->inbound, in, recv_ringbuffer_size);
160 /* Establish the gpadl for the ring buffer */
161 newchannel->ringbuffer_gpadlhandle = 0;
163 ret = vmbus_establish_gpadl(newchannel,
164 newchannel->outbound.ring_buffer,
165 send_ringbuffer_size +
166 recv_ringbuffer_size,
167 &newchannel->ringbuffer_gpadlhandle);
174 /* Create and init the channel open message */
175 open_info = kmalloc(sizeof(*open_info) +
176 sizeof(struct vmbus_channel_open_channel),
183 init_completion(&open_info->waitevent);
185 open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
186 open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
187 open_msg->openid = newchannel->offermsg.child_relid;
188 open_msg->child_relid = newchannel->offermsg.child_relid;
189 open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
190 open_msg->downstream_ringbuffer_pageoffset = send_ringbuffer_size >>
192 open_msg->server_contextarea_gpadlhandle = 0;
194 if (userdatalen > MAX_USER_DEFINED_BYTES) {
200 memcpy(open_msg->userdata, userdata, userdatalen);
202 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
203 list_add_tail(&open_info->msglistentry,
204 &vmbus_connection.chn_msg_list);
205 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
207 ret = vmbus_post_msg(open_msg,
208 sizeof(struct vmbus_channel_open_channel));
213 t = wait_for_completion_timeout(&open_info->waitevent, 5*HZ);
220 if (open_info->response.open_result.status)
221 err = open_info->response.open_result.status;
223 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
224 list_del(&open_info->msglistentry);
225 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
231 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
232 list_del(&open_info->msglistentry);
233 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
236 free_pages((unsigned long)out,
237 get_order(send_ringbuffer_size + recv_ringbuffer_size));
241 EXPORT_SYMBOL_GPL(vmbus_open);
244 * create_gpadl_header - Creates a gpadl for the specified buffer
246 static int create_gpadl_header(void *kbuffer, u32 size,
247 struct vmbus_channel_msginfo **msginfo,
252 unsigned long long pfn;
253 struct vmbus_channel_gpadl_header *gpadl_header;
254 struct vmbus_channel_gpadl_body *gpadl_body;
255 struct vmbus_channel_msginfo *msgheader;
256 struct vmbus_channel_msginfo *msgbody = NULL;
259 int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
261 pagecount = size >> PAGE_SHIFT;
262 pfn = virt_to_phys(kbuffer) >> PAGE_SHIFT;
264 /* do we need a gpadl body msg */
265 pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
266 sizeof(struct vmbus_channel_gpadl_header) -
267 sizeof(struct gpa_range);
268 pfncount = pfnsize / sizeof(u64);
270 if (pagecount > pfncount) {
271 /* we need a gpadl body */
272 /* fill in the header */
273 msgsize = sizeof(struct vmbus_channel_msginfo) +
274 sizeof(struct vmbus_channel_gpadl_header) +
275 sizeof(struct gpa_range) + pfncount * sizeof(u64);
276 msgheader = kzalloc(msgsize, GFP_KERNEL);
280 INIT_LIST_HEAD(&msgheader->submsglist);
281 msgheader->msgsize = msgsize;
283 gpadl_header = (struct vmbus_channel_gpadl_header *)
285 gpadl_header->rangecount = 1;
286 gpadl_header->range_buflen = sizeof(struct gpa_range) +
287 pagecount * sizeof(u64);
288 gpadl_header->range[0].byte_offset = 0;
289 gpadl_header->range[0].byte_count = size;
290 for (i = 0; i < pfncount; i++)
291 gpadl_header->range[0].pfn_array[i] = pfn+i;
292 *msginfo = msgheader;
296 pfnleft = pagecount - pfncount;
298 /* how many pfns can we fit */
299 pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
300 sizeof(struct vmbus_channel_gpadl_body);
301 pfncount = pfnsize / sizeof(u64);
303 /* fill in the body */
305 if (pfnleft > pfncount)
310 msgsize = sizeof(struct vmbus_channel_msginfo) +
311 sizeof(struct vmbus_channel_gpadl_body) +
312 pfncurr * sizeof(u64);
313 msgbody = kzalloc(msgsize, GFP_KERNEL);
316 struct vmbus_channel_msginfo *pos = NULL;
317 struct vmbus_channel_msginfo *tmp = NULL;
319 * Free up all the allocated messages.
321 list_for_each_entry_safe(pos, tmp,
322 &msgheader->submsglist,
325 list_del(&pos->msglistentry);
332 msgbody->msgsize = msgsize;
335 (struct vmbus_channel_gpadl_body *)msgbody->msg;
338 * Gpadl is u32 and we are using a pointer which could
340 * This is governed by the guest/host protocol and
341 * so the hypervisor gurantees that this is ok.
343 for (i = 0; i < pfncurr; i++)
344 gpadl_body->pfn[i] = pfn + pfnsum + i;
346 /* add to msg header */
347 list_add_tail(&msgbody->msglistentry,
348 &msgheader->submsglist);
353 /* everything fits in a header */
354 msgsize = sizeof(struct vmbus_channel_msginfo) +
355 sizeof(struct vmbus_channel_gpadl_header) +
356 sizeof(struct gpa_range) + pagecount * sizeof(u64);
357 msgheader = kzalloc(msgsize, GFP_KERNEL);
358 if (msgheader == NULL)
360 msgheader->msgsize = msgsize;
362 gpadl_header = (struct vmbus_channel_gpadl_header *)
364 gpadl_header->rangecount = 1;
365 gpadl_header->range_buflen = sizeof(struct gpa_range) +
366 pagecount * sizeof(u64);
367 gpadl_header->range[0].byte_offset = 0;
368 gpadl_header->range[0].byte_count = size;
369 for (i = 0; i < pagecount; i++)
370 gpadl_header->range[0].pfn_array[i] = pfn+i;
372 *msginfo = msgheader;
384 * vmbus_establish_gpadl - Estabish a GPADL for the specified buffer
386 * @channel: a channel
387 * @kbuffer: from kmalloc
388 * @size: page-size multiple
389 * @gpadl_handle: some funky thing
391 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
392 u32 size, u32 *gpadl_handle)
394 struct vmbus_channel_gpadl_header *gpadlmsg;
395 struct vmbus_channel_gpadl_body *gpadl_body;
396 struct vmbus_channel_msginfo *msginfo = NULL;
397 struct vmbus_channel_msginfo *submsginfo;
399 struct list_head *curr;
400 u32 next_gpadl_handle;
405 next_gpadl_handle = atomic_read(&vmbus_connection.next_gpadl_handle);
406 atomic_inc(&vmbus_connection.next_gpadl_handle);
408 ret = create_gpadl_header(kbuffer, size, &msginfo, &msgcount);
412 init_completion(&msginfo->waitevent);
414 gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
415 gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
416 gpadlmsg->child_relid = channel->offermsg.child_relid;
417 gpadlmsg->gpadl = next_gpadl_handle;
420 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
421 list_add_tail(&msginfo->msglistentry,
422 &vmbus_connection.chn_msg_list);
424 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
426 ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
432 list_for_each(curr, &msginfo->submsglist) {
434 submsginfo = (struct vmbus_channel_msginfo *)curr;
436 (struct vmbus_channel_gpadl_body *)submsginfo->msg;
438 gpadl_body->header.msgtype =
439 CHANNELMSG_GPADL_BODY;
440 gpadl_body->gpadl = next_gpadl_handle;
442 ret = vmbus_post_msg(gpadl_body,
443 submsginfo->msgsize -
444 sizeof(*submsginfo));
450 t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
454 /* At this point, we received the gpadl created msg */
455 *gpadl_handle = gpadlmsg->gpadl;
458 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
459 list_del(&msginfo->msglistentry);
460 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
465 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
468 * vmbus_teardown_gpadl -Teardown the specified GPADL handle
470 int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
472 struct vmbus_channel_gpadl_teardown *msg;
473 struct vmbus_channel_msginfo *info;
477 info = kmalloc(sizeof(*info) +
478 sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
482 init_completion(&info->waitevent);
484 msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
486 msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
487 msg->child_relid = channel->offermsg.child_relid;
488 msg->gpadl = gpadl_handle;
490 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
491 list_add_tail(&info->msglistentry,
492 &vmbus_connection.chn_msg_list);
493 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
494 ret = vmbus_post_msg(msg,
495 sizeof(struct vmbus_channel_gpadl_teardown));
500 wait_for_completion(&info->waitevent);
503 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
504 list_del(&info->msglistentry);
505 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
510 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
513 * vmbus_close - Close the specified channel
515 void vmbus_close(struct vmbus_channel *channel)
517 struct vmbus_channel_close_channel *msg;
521 /* Stop callback and cancel the timer asap */
522 spin_lock_irqsave(&channel->inbound_lock, flags);
523 channel->onchannel_callback = NULL;
524 spin_unlock_irqrestore(&channel->inbound_lock, flags);
526 /* Send a closing message */
528 msg = &channel->close_msg.msg;
530 msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
531 msg->child_relid = channel->offermsg.child_relid;
533 ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel));
536 /* Tear down the gpadl for the channel's ring buffer */
537 if (channel->ringbuffer_gpadlhandle)
538 vmbus_teardown_gpadl(channel,
539 channel->ringbuffer_gpadlhandle);
541 /* Cleanup the ring buffers for this channel */
542 hv_ringbuffer_cleanup(&channel->outbound);
543 hv_ringbuffer_cleanup(&channel->inbound);
545 free_pages((unsigned long)channel->ringbuffer_pages,
546 get_order(channel->ringbuffer_pagecount * PAGE_SIZE));
550 EXPORT_SYMBOL_GPL(vmbus_close);
553 * vmbus_sendpacket() - Send the specified buffer on the given channel
554 * @channel: Pointer to vmbus_channel structure.
555 * @buffer: Pointer to the buffer you want to receive the data into.
556 * @bufferlen: Maximum size of what the the buffer will hold
557 * @requestid: Identifier of the request
558 * @type: Type of packet that is being send e.g. negotiate, time
561 * Sends data in @buffer directly to hyper-v via the vmbus
562 * This will send the data unparsed to hyper-v.
564 * Mainly used by Hyper-V drivers.
566 int vmbus_sendpacket(struct vmbus_channel *channel, const void *buffer,
567 u32 bufferlen, u64 requestid,
568 enum vmbus_packet_type type, u32 flags)
570 struct vmpacket_descriptor desc;
571 u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
572 u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
573 struct scatterlist bufferlist[3];
574 u64 aligned_data = 0;
578 /* Setup the descriptor */
579 desc.type = type; /* VmbusPacketTypeDataInBand; */
580 desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
581 /* in 8-bytes granularity */
582 desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
583 desc.len8 = (u16)(packetlen_aligned >> 3);
584 desc.trans_id = requestid;
586 sg_init_table(bufferlist, 3);
587 sg_set_buf(&bufferlist[0], &desc, sizeof(struct vmpacket_descriptor));
588 sg_set_buf(&bufferlist[1], buffer, bufferlen);
589 sg_set_buf(&bufferlist[2], &aligned_data,
590 packetlen_aligned - packetlen);
592 ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3);
594 if (ret == 0 && !hv_get_ringbuffer_interrupt_mask(&channel->outbound))
595 vmbus_setevent(channel);
599 EXPORT_SYMBOL(vmbus_sendpacket);
602 * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
603 * packets using a GPADL Direct packet type.
605 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
606 struct hv_page_buffer pagebuffers[],
607 u32 pagecount, void *buffer, u32 bufferlen,
612 struct vmbus_channel_packet_page_buffer desc;
615 u32 packetlen_aligned;
616 struct scatterlist bufferlist[3];
617 u64 aligned_data = 0;
619 if (pagecount > MAX_PAGE_BUFFER_COUNT)
624 * Adjust the size down since vmbus_channel_packet_page_buffer is the
625 * largest size we support
627 descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
628 ((MAX_PAGE_BUFFER_COUNT - pagecount) *
629 sizeof(struct hv_page_buffer));
630 packetlen = descsize + bufferlen;
631 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
633 /* Setup the descriptor */
634 desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
635 desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
636 desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
637 desc.length8 = (u16)(packetlen_aligned >> 3);
638 desc.transactionid = requestid;
639 desc.rangecount = pagecount;
641 for (i = 0; i < pagecount; i++) {
642 desc.range[i].len = pagebuffers[i].len;
643 desc.range[i].offset = pagebuffers[i].offset;
644 desc.range[i].pfn = pagebuffers[i].pfn;
647 sg_init_table(bufferlist, 3);
648 sg_set_buf(&bufferlist[0], &desc, descsize);
649 sg_set_buf(&bufferlist[1], buffer, bufferlen);
650 sg_set_buf(&bufferlist[2], &aligned_data,
651 packetlen_aligned - packetlen);
653 ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3);
655 if (ret == 0 && !hv_get_ringbuffer_interrupt_mask(&channel->outbound))
656 vmbus_setevent(channel);
660 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
663 * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
664 * using a GPADL Direct packet type.
666 int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
667 struct hv_multipage_buffer *multi_pagebuffer,
668 void *buffer, u32 bufferlen, u64 requestid)
671 struct vmbus_channel_packet_multipage_buffer desc;
674 u32 packetlen_aligned;
675 struct scatterlist bufferlist[3];
676 u64 aligned_data = 0;
677 u32 pfncount = NUM_PAGES_SPANNED(multi_pagebuffer->offset,
678 multi_pagebuffer->len);
681 if ((pfncount < 0) || (pfncount > MAX_MULTIPAGE_BUFFER_COUNT))
685 * Adjust the size down since vmbus_channel_packet_multipage_buffer is
686 * the largest size we support
688 descsize = sizeof(struct vmbus_channel_packet_multipage_buffer) -
689 ((MAX_MULTIPAGE_BUFFER_COUNT - pfncount) *
691 packetlen = descsize + bufferlen;
692 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
695 /* Setup the descriptor */
696 desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
697 desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
698 desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
699 desc.length8 = (u16)(packetlen_aligned >> 3);
700 desc.transactionid = requestid;
703 desc.range.len = multi_pagebuffer->len;
704 desc.range.offset = multi_pagebuffer->offset;
706 memcpy(desc.range.pfn_array, multi_pagebuffer->pfn_array,
707 pfncount * sizeof(u64));
709 sg_init_table(bufferlist, 3);
710 sg_set_buf(&bufferlist[0], &desc, descsize);
711 sg_set_buf(&bufferlist[1], buffer, bufferlen);
712 sg_set_buf(&bufferlist[2], &aligned_data,
713 packetlen_aligned - packetlen);
715 ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3);
717 if (ret == 0 && !hv_get_ringbuffer_interrupt_mask(&channel->outbound))
718 vmbus_setevent(channel);
722 EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer);
725 * vmbus_recvpacket() - Retrieve the user packet on the specified channel
726 * @channel: Pointer to vmbus_channel structure.
727 * @buffer: Pointer to the buffer you want to receive the data into.
728 * @bufferlen: Maximum size of what the the buffer will hold
729 * @buffer_actual_len: The actual size of the data after it was received
730 * @requestid: Identifier of the request
732 * Receives directly from the hyper-v vmbus and puts the data it received
733 * into Buffer. This will receive the data unparsed from hyper-v.
735 * Mainly used by Hyper-V drivers.
737 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
738 u32 bufferlen, u32 *buffer_actual_len, u64 *requestid)
740 struct vmpacket_descriptor desc;
745 *buffer_actual_len = 0;
749 ret = hv_ringbuffer_peek(&channel->inbound, &desc,
750 sizeof(struct vmpacket_descriptor));
754 packetlen = desc.len8 << 3;
755 userlen = packetlen - (desc.offset8 << 3);
757 *buffer_actual_len = userlen;
759 if (userlen > bufferlen) {
761 pr_err("Buffer too small - got %d needs %d\n",
766 *requestid = desc.trans_id;
768 /* Copy over the packet to the user buffer */
769 ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen,
770 (desc.offset8 << 3));
775 EXPORT_SYMBOL(vmbus_recvpacket);
778 * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
780 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
781 u32 bufferlen, u32 *buffer_actual_len,
784 struct vmpacket_descriptor desc;
789 *buffer_actual_len = 0;
793 ret = hv_ringbuffer_peek(&channel->inbound, &desc,
794 sizeof(struct vmpacket_descriptor));
799 packetlen = desc.len8 << 3;
800 userlen = packetlen - (desc.offset8 << 3);
802 *buffer_actual_len = packetlen;
804 if (packetlen > bufferlen) {
805 pr_err("Buffer too small - needed %d bytes but "
806 "got space for only %d bytes\n",
807 packetlen, bufferlen);
811 *requestid = desc.trans_id;
813 /* Copy over the entire packet to the user buffer */
814 ret = hv_ringbuffer_read(&channel->inbound, buffer, packetlen, 0);
818 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);