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/interrupt.h>
25 #include <linux/sched.h>
26 #include <linux/wait.h>
28 #include <linux/slab.h>
29 #include <linux/list.h>
30 #include <linux/module.h>
31 #include <linux/completion.h>
32 #include <linux/delay.h>
33 #include <linux/hyperv.h>
34 #include <asm/mshyperv.h>
36 #include "hyperv_vmbus.h"
38 static void init_vp_index(struct vmbus_channel *channel, u16 dev_type);
40 static const struct vmbus_device vmbus_devs[] = {
48 { .dev_type = HV_SCSI,
72 { .dev_type = HV_PCIE,
77 /* Synthetic Frame Buffer */
83 /* Synthetic Keyboard */
90 { .dev_type = HV_MOUSE,
104 .perf_device = false,
110 .perf_device = false,
114 { .dev_type = HV_SHUTDOWN,
116 .perf_device = false,
120 { .dev_type = HV_FCOPY,
122 .perf_device = false,
126 { .dev_type = HV_BACKUP,
128 .perf_device = false,
134 .perf_device = false,
138 { .dev_type = HV_UNKNOWN,
139 .perf_device = false,
143 static const struct {
145 } vmbus_unsupported_devs[] = {
152 * The rescinded channel may be blocked waiting for a response from the host;
155 static void vmbus_rescind_cleanup(struct vmbus_channel *channel)
157 struct vmbus_channel_msginfo *msginfo;
161 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
162 channel->rescind = true;
163 list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
166 if (msginfo->waiting_channel == channel) {
167 complete(&msginfo->waitevent);
171 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
174 static bool is_unsupported_vmbus_devs(const uuid_le *guid)
178 for (i = 0; i < ARRAY_SIZE(vmbus_unsupported_devs); i++)
179 if (!uuid_le_cmp(*guid, vmbus_unsupported_devs[i].guid))
184 static u16 hv_get_dev_type(const struct vmbus_channel *channel)
186 const uuid_le *guid = &channel->offermsg.offer.if_type;
189 if (is_hvsock_channel(channel) || is_unsupported_vmbus_devs(guid))
192 for (i = HV_IDE; i < HV_UNKNOWN; i++) {
193 if (!uuid_le_cmp(*guid, vmbus_devs[i].guid))
196 pr_info("Unknown GUID: %pUl\n", guid);
201 * vmbus_prep_negotiate_resp() - Create default response for Hyper-V Negotiate message
202 * @icmsghdrp: Pointer to msg header structure
203 * @icmsg_negotiate: Pointer to negotiate message structure
204 * @buf: Raw buffer channel data
206 * @icmsghdrp is of type &struct icmsg_hdr.
207 * Set up and fill in default negotiate response message.
209 * The fw_version and fw_vercnt specifies the framework version that
212 * The srv_version and srv_vercnt specifies the service
213 * versions we can support.
215 * Versions are given in decreasing order.
217 * nego_fw_version and nego_srv_version store the selected protocol versions.
219 * Mainly used by Hyper-V drivers.
221 bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
222 u8 *buf, const int *fw_version, int fw_vercnt,
223 const int *srv_version, int srv_vercnt,
224 int *nego_fw_version, int *nego_srv_version)
226 int icframe_major, icframe_minor;
227 int icmsg_major, icmsg_minor;
228 int fw_major, fw_minor;
229 int srv_major, srv_minor;
231 bool found_match = false;
232 struct icmsg_negotiate *negop;
234 icmsghdrp->icmsgsize = 0x10;
235 negop = (struct icmsg_negotiate *)&buf[
236 sizeof(struct vmbuspipe_hdr) +
237 sizeof(struct icmsg_hdr)];
239 icframe_major = negop->icframe_vercnt;
242 icmsg_major = negop->icmsg_vercnt;
246 * Select the framework version number we will
250 for (i = 0; i < fw_vercnt; i++) {
251 fw_major = (fw_version[i] >> 16);
252 fw_minor = (fw_version[i] & 0xFFFF);
254 for (j = 0; j < negop->icframe_vercnt; j++) {
255 if ((negop->icversion_data[j].major == fw_major) &&
256 (negop->icversion_data[j].minor == fw_minor)) {
257 icframe_major = negop->icversion_data[j].major;
258 icframe_minor = negop->icversion_data[j].minor;
273 for (i = 0; i < srv_vercnt; i++) {
274 srv_major = (srv_version[i] >> 16);
275 srv_minor = (srv_version[i] & 0xFFFF);
277 for (j = negop->icframe_vercnt;
278 (j < negop->icframe_vercnt + negop->icmsg_vercnt);
281 if ((negop->icversion_data[j].major == srv_major) &&
282 (negop->icversion_data[j].minor == srv_minor)) {
284 icmsg_major = negop->icversion_data[j].major;
285 icmsg_minor = negop->icversion_data[j].minor;
296 * Respond with the framework and service
297 * version numbers we can support.
302 negop->icframe_vercnt = 0;
303 negop->icmsg_vercnt = 0;
305 negop->icframe_vercnt = 1;
306 negop->icmsg_vercnt = 1;
310 *nego_fw_version = (icframe_major << 16) | icframe_minor;
312 if (nego_srv_version)
313 *nego_srv_version = (icmsg_major << 16) | icmsg_minor;
315 negop->icversion_data[0].major = icframe_major;
316 negop->icversion_data[0].minor = icframe_minor;
317 negop->icversion_data[1].major = icmsg_major;
318 negop->icversion_data[1].minor = icmsg_minor;
322 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
325 * alloc_channel - Allocate and initialize a vmbus channel object
327 static struct vmbus_channel *alloc_channel(void)
329 struct vmbus_channel *channel;
331 channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
335 spin_lock_init(&channel->lock);
336 init_completion(&channel->rescind_event);
338 INIT_LIST_HEAD(&channel->sc_list);
339 INIT_LIST_HEAD(&channel->percpu_list);
341 tasklet_init(&channel->callback_event,
342 vmbus_on_event, (unsigned long)channel);
348 * free_channel - Release the resources used by the vmbus channel object
350 static void free_channel(struct vmbus_channel *channel)
352 tasklet_kill(&channel->callback_event);
353 vmbus_remove_channel_attr_group(channel);
355 kobject_put(&channel->kobj);
358 static void percpu_channel_enq(void *arg)
360 struct vmbus_channel *channel = arg;
361 struct hv_per_cpu_context *hv_cpu
362 = this_cpu_ptr(hv_context.cpu_context);
364 list_add_tail_rcu(&channel->percpu_list, &hv_cpu->chan_list);
367 static void percpu_channel_deq(void *arg)
369 struct vmbus_channel *channel = arg;
371 list_del_rcu(&channel->percpu_list);
375 static void vmbus_release_relid(u32 relid)
377 struct vmbus_channel_relid_released msg;
380 memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
381 msg.child_relid = relid;
382 msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
383 ret = vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released),
386 trace_vmbus_release_relid(&msg, ret);
389 void hv_process_channel_removal(u32 relid)
392 struct vmbus_channel *primary_channel, *channel;
394 BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex));
397 * Make sure channel is valid as we may have raced.
399 channel = relid2channel(relid);
403 BUG_ON(!channel->rescind);
404 if (channel->target_cpu != get_cpu()) {
406 smp_call_function_single(channel->target_cpu,
407 percpu_channel_deq, channel, true);
409 percpu_channel_deq(channel);
413 if (channel->primary_channel == NULL) {
414 list_del(&channel->listentry);
416 primary_channel = channel;
418 primary_channel = channel->primary_channel;
419 spin_lock_irqsave(&primary_channel->lock, flags);
420 list_del(&channel->sc_list);
421 primary_channel->num_sc--;
422 spin_unlock_irqrestore(&primary_channel->lock, flags);
426 * We need to free the bit for init_vp_index() to work in the case
427 * of sub-channel, when we reload drivers like hv_netvsc.
429 if (channel->affinity_policy == HV_LOCALIZED)
430 cpumask_clear_cpu(channel->target_cpu,
431 &primary_channel->alloced_cpus_in_node);
433 vmbus_release_relid(relid);
435 free_channel(channel);
438 void vmbus_free_channels(void)
440 struct vmbus_channel *channel, *tmp;
442 list_for_each_entry_safe(channel, tmp, &vmbus_connection.chn_list,
444 /* hv_process_channel_removal() needs this */
445 channel->rescind = true;
447 vmbus_device_unregister(channel->device_obj);
451 /* Note: the function can run concurrently for primary/sub channels. */
452 static void vmbus_add_channel_work(struct work_struct *work)
454 struct vmbus_channel *newchannel =
455 container_of(work, struct vmbus_channel, add_channel_work);
456 struct vmbus_channel *primary_channel = newchannel->primary_channel;
461 dev_type = hv_get_dev_type(newchannel);
463 init_vp_index(newchannel, dev_type);
465 if (newchannel->target_cpu != get_cpu()) {
467 smp_call_function_single(newchannel->target_cpu,
471 percpu_channel_enq(newchannel);
476 * This state is used to indicate a successful open
477 * so that when we do close the channel normally, we
478 * can cleanup properly.
480 newchannel->state = CHANNEL_OPEN_STATE;
482 if (primary_channel != NULL) {
483 /* newchannel is a sub-channel. */
484 struct hv_device *dev = primary_channel->device_obj;
486 if (vmbus_add_channel_kobj(dev, newchannel))
489 if (primary_channel->sc_creation_callback != NULL)
490 primary_channel->sc_creation_callback(newchannel);
492 newchannel->probe_done = true;
497 * Start the process of binding the primary channel to the driver
499 newchannel->device_obj = vmbus_device_create(
500 &newchannel->offermsg.offer.if_type,
501 &newchannel->offermsg.offer.if_instance,
503 if (!newchannel->device_obj)
506 newchannel->device_obj->device_id = dev_type;
508 * Add the new device to the bus. This will kick off device-driver
509 * binding which eventually invokes the device driver's AddDevice()
512 * If vmbus_device_register() fails, the 'device_obj' is freed in
513 * vmbus_device_release() as called by device_unregister() in the
514 * error path of vmbus_device_register(). In the outside error
515 * path, there's no need to free it.
517 ret = vmbus_device_register(newchannel->device_obj);
520 pr_err("unable to add child device object (relid %d)\n",
521 newchannel->offermsg.child_relid);
525 newchannel->probe_done = true;
529 mutex_lock(&vmbus_connection.channel_mutex);
532 * We need to set the flag, otherwise
533 * vmbus_onoffer_rescind() can be blocked.
535 newchannel->probe_done = true;
537 if (primary_channel == NULL) {
538 list_del(&newchannel->listentry);
540 spin_lock_irqsave(&primary_channel->lock, flags);
541 list_del(&newchannel->sc_list);
542 spin_unlock_irqrestore(&primary_channel->lock, flags);
545 mutex_unlock(&vmbus_connection.channel_mutex);
547 if (newchannel->target_cpu != get_cpu()) {
549 smp_call_function_single(newchannel->target_cpu,
553 percpu_channel_deq(newchannel);
557 vmbus_release_relid(newchannel->offermsg.child_relid);
559 free_channel(newchannel);
563 * vmbus_process_offer - Process the offer by creating a channel/device
564 * associated with this offer
566 static void vmbus_process_offer(struct vmbus_channel *newchannel)
568 struct vmbus_channel *channel;
569 struct workqueue_struct *wq;
573 mutex_lock(&vmbus_connection.channel_mutex);
576 * Now that we have acquired the channel_mutex,
577 * we can release the potentially racing rescind thread.
579 atomic_dec(&vmbus_connection.offer_in_progress);
581 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
582 if (!uuid_le_cmp(channel->offermsg.offer.if_type,
583 newchannel->offermsg.offer.if_type) &&
584 !uuid_le_cmp(channel->offermsg.offer.if_instance,
585 newchannel->offermsg.offer.if_instance)) {
592 list_add_tail(&newchannel->listentry,
593 &vmbus_connection.chn_list);
596 * Check to see if this is a valid sub-channel.
598 if (newchannel->offermsg.offer.sub_channel_index == 0) {
599 mutex_unlock(&vmbus_connection.channel_mutex);
601 * Don't call free_channel(), because newchannel->kobj
602 * is not initialized yet.
609 * Process the sub-channel.
611 newchannel->primary_channel = channel;
612 spin_lock_irqsave(&channel->lock, flags);
613 list_add_tail(&newchannel->sc_list, &channel->sc_list);
614 spin_unlock_irqrestore(&channel->lock, flags);
617 mutex_unlock(&vmbus_connection.channel_mutex);
620 * vmbus_process_offer() mustn't call channel->sc_creation_callback()
621 * directly for sub-channels, because sc_creation_callback() ->
622 * vmbus_open() may never get the host's response to the
623 * OPEN_CHANNEL message (the host may rescind a channel at any time,
624 * e.g. in the case of hot removing a NIC), and vmbus_onoffer_rescind()
625 * may not wake up the vmbus_open() as it's blocked due to a non-zero
626 * vmbus_connection.offer_in_progress, and finally we have a deadlock.
628 * The above is also true for primary channels, if the related device
629 * drivers use sync probing mode by default.
631 * And, usually the handling of primary channels and sub-channels can
632 * depend on each other, so we should offload them to different
633 * workqueues to avoid possible deadlock, e.g. in sync-probing mode,
634 * NIC1's netvsc_subchan_work() can race with NIC2's netvsc_probe() ->
635 * rtnl_lock(), and causes deadlock: the former gets the rtnl_lock
636 * and waits for all the sub-channels to appear, but the latter
637 * can't get the rtnl_lock and this blocks the handling of
640 INIT_WORK(&newchannel->add_channel_work, vmbus_add_channel_work);
641 wq = fnew ? vmbus_connection.handle_primary_chan_wq :
642 vmbus_connection.handle_sub_chan_wq;
643 queue_work(wq, &newchannel->add_channel_work);
647 * We use this state to statically distribute the channel interrupt load.
649 static int next_numa_node_id;
651 * init_vp_index() accesses global variables like next_numa_node_id, and
652 * it can run concurrently for primary channels and sub-channels: see
653 * vmbus_process_offer(), so we need the lock to protect the global
656 static DEFINE_SPINLOCK(bind_channel_to_cpu_lock);
659 * Starting with Win8, we can statically distribute the incoming
660 * channel interrupt load by binding a channel to VCPU.
661 * We distribute the interrupt loads to one or more NUMA nodes based on
662 * the channel's affinity_policy.
664 * For pre-win8 hosts or non-performance critical channels we assign the
665 * first CPU in the first NUMA node.
667 static void init_vp_index(struct vmbus_channel *channel, u16 dev_type)
670 bool perf_chn = vmbus_devs[dev_type].perf_device;
671 struct vmbus_channel *primary = channel->primary_channel;
673 cpumask_var_t available_mask;
674 struct cpumask *alloced_mask;
676 if ((vmbus_proto_version == VERSION_WS2008) ||
677 (vmbus_proto_version == VERSION_WIN7) || (!perf_chn) ||
678 !alloc_cpumask_var(&available_mask, GFP_KERNEL)) {
680 * Prior to win8, all channel interrupts are
681 * delivered on cpu 0.
682 * Also if the channel is not a performance critical
683 * channel, bind it to cpu 0.
684 * In case alloc_cpumask_var() fails, bind it to cpu 0.
686 channel->numa_node = 0;
687 channel->target_cpu = 0;
688 channel->target_vp = hv_cpu_number_to_vp_number(0);
692 spin_lock(&bind_channel_to_cpu_lock);
695 * Based on the channel affinity policy, we will assign the NUMA
699 if ((channel->affinity_policy == HV_BALANCED) || (!primary)) {
701 next_node = next_numa_node_id++;
702 if (next_node == nr_node_ids) {
703 next_node = next_numa_node_id = 0;
706 if (cpumask_empty(cpumask_of_node(next_node)))
710 channel->numa_node = next_node;
713 alloced_mask = &hv_context.hv_numa_map[primary->numa_node];
715 if (cpumask_weight(alloced_mask) ==
716 cpumask_weight(cpumask_of_node(primary->numa_node))) {
718 * We have cycled through all the CPUs in the node;
719 * reset the alloced map.
721 cpumask_clear(alloced_mask);
724 cpumask_xor(available_mask, alloced_mask,
725 cpumask_of_node(primary->numa_node));
729 if (primary->affinity_policy == HV_LOCALIZED) {
731 * Normally Hyper-V host doesn't create more subchannels
732 * than there are VCPUs on the node but it is possible when not
733 * all present VCPUs on the node are initialized by guest.
734 * Clear the alloced_cpus_in_node to start over.
736 if (cpumask_equal(&primary->alloced_cpus_in_node,
737 cpumask_of_node(primary->numa_node)))
738 cpumask_clear(&primary->alloced_cpus_in_node);
742 cur_cpu = cpumask_next(cur_cpu, available_mask);
743 if (cur_cpu >= nr_cpu_ids) {
745 cpumask_copy(available_mask,
746 cpumask_of_node(primary->numa_node));
750 if (primary->affinity_policy == HV_LOCALIZED) {
752 * NOTE: in the case of sub-channel, we clear the
753 * sub-channel related bit(s) in
754 * primary->alloced_cpus_in_node in
755 * hv_process_channel_removal(), so when we
756 * reload drivers like hv_netvsc in SMP guest, here
757 * we're able to re-allocate
758 * bit from primary->alloced_cpus_in_node.
760 if (!cpumask_test_cpu(cur_cpu,
761 &primary->alloced_cpus_in_node)) {
762 cpumask_set_cpu(cur_cpu,
763 &primary->alloced_cpus_in_node);
764 cpumask_set_cpu(cur_cpu, alloced_mask);
768 cpumask_set_cpu(cur_cpu, alloced_mask);
773 channel->target_cpu = cur_cpu;
774 channel->target_vp = hv_cpu_number_to_vp_number(cur_cpu);
776 spin_unlock(&bind_channel_to_cpu_lock);
778 free_cpumask_var(available_mask);
781 #define UNLOAD_DELAY_UNIT_MS 10 /* 10 milliseconds */
782 #define UNLOAD_WAIT_MS (100*1000) /* 100 seconds */
783 #define UNLOAD_WAIT_LOOPS (UNLOAD_WAIT_MS/UNLOAD_DELAY_UNIT_MS)
784 #define UNLOAD_MSG_MS (5*1000) /* Every 5 seconds */
785 #define UNLOAD_MSG_LOOPS (UNLOAD_MSG_MS/UNLOAD_DELAY_UNIT_MS)
787 static void vmbus_wait_for_unload(void)
791 struct hv_message *msg;
792 struct vmbus_channel_message_header *hdr;
796 * CHANNELMSG_UNLOAD_RESPONSE is always delivered to the CPU which was
797 * used for initial contact or to CPU0 depending on host version. When
798 * we're crashing on a different CPU let's hope that IRQ handler on
799 * the cpu which receives CHANNELMSG_UNLOAD_RESPONSE is still
800 * functional and vmbus_unload_response() will complete
801 * vmbus_connection.unload_event. If not, the last thing we can do is
802 * read message pages for all CPUs directly.
804 * Wait up to 100 seconds since an Azure host must writeback any dirty
805 * data in its disk cache before the VMbus UNLOAD request will
806 * complete. This flushing has been empirically observed to take up
807 * to 50 seconds in cases with a lot of dirty data, so allow additional
808 * leeway and for inaccuracies in mdelay(). But eventually time out so
809 * that the panic path can't get hung forever in case the response
810 * message isn't seen.
812 for (i = 1; i <= UNLOAD_WAIT_LOOPS; i++) {
813 if (completion_done(&vmbus_connection.unload_event))
816 for_each_online_cpu(cpu) {
817 struct hv_per_cpu_context *hv_cpu
818 = per_cpu_ptr(hv_context.cpu_context, cpu);
820 page_addr = hv_cpu->synic_message_page;
821 msg = (struct hv_message *)page_addr
822 + VMBUS_MESSAGE_SINT;
824 message_type = READ_ONCE(msg->header.message_type);
825 if (message_type == HVMSG_NONE)
828 hdr = (struct vmbus_channel_message_header *)
831 if (hdr->msgtype == CHANNELMSG_UNLOAD_RESPONSE)
832 complete(&vmbus_connection.unload_event);
834 vmbus_signal_eom(msg, message_type);
838 * Give a notice periodically so someone watching the
839 * serial output won't think it is completely hung.
841 if (!(i % UNLOAD_MSG_LOOPS))
842 pr_notice("Waiting for VMBus UNLOAD to complete\n");
844 mdelay(UNLOAD_DELAY_UNIT_MS);
846 pr_err("Continuing even though VMBus UNLOAD did not complete\n");
850 * We're crashing and already got the UNLOAD_RESPONSE, cleanup all
851 * maybe-pending messages on all CPUs to be able to receive new
852 * messages after we reconnect.
854 for_each_online_cpu(cpu) {
855 struct hv_per_cpu_context *hv_cpu
856 = per_cpu_ptr(hv_context.cpu_context, cpu);
858 page_addr = hv_cpu->synic_message_page;
859 msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
860 msg->header.message_type = HVMSG_NONE;
865 * vmbus_unload_response - Handler for the unload response.
867 static void vmbus_unload_response(struct vmbus_channel_message_header *hdr)
870 * This is a global event; just wakeup the waiting thread.
871 * Once we successfully unload, we can cleanup the monitor state.
873 complete(&vmbus_connection.unload_event);
876 void vmbus_initiate_unload(bool crash)
878 struct vmbus_channel_message_header hdr;
880 if (xchg(&vmbus_connection.conn_state, DISCONNECTED) == DISCONNECTED)
883 /* Pre-Win2012R2 hosts don't support reconnect */
884 if (vmbus_proto_version < VERSION_WIN8_1)
887 init_completion(&vmbus_connection.unload_event);
888 memset(&hdr, 0, sizeof(struct vmbus_channel_message_header));
889 hdr.msgtype = CHANNELMSG_UNLOAD;
890 vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header),
894 * vmbus_initiate_unload() is also called on crash and the crash can be
895 * happening in an interrupt context, where scheduling is impossible.
898 wait_for_completion(&vmbus_connection.unload_event);
900 vmbus_wait_for_unload();
904 * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
907 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
909 struct vmbus_channel_offer_channel *offer;
910 struct vmbus_channel *newchannel;
912 offer = (struct vmbus_channel_offer_channel *)hdr;
914 trace_vmbus_onoffer(offer);
916 /* Allocate the channel object and save this offer. */
917 newchannel = alloc_channel();
919 vmbus_release_relid(offer->child_relid);
920 atomic_dec(&vmbus_connection.offer_in_progress);
921 pr_err("Unable to allocate channel object\n");
926 * Setup state for signalling the host.
928 newchannel->sig_event = VMBUS_EVENT_CONNECTION_ID;
930 if (vmbus_proto_version != VERSION_WS2008) {
931 newchannel->is_dedicated_interrupt =
932 (offer->is_dedicated_interrupt != 0);
933 newchannel->sig_event = offer->connection_id;
936 memcpy(&newchannel->offermsg, offer,
937 sizeof(struct vmbus_channel_offer_channel));
938 newchannel->monitor_grp = (u8)offer->monitorid / 32;
939 newchannel->monitor_bit = (u8)offer->monitorid % 32;
941 vmbus_process_offer(newchannel);
945 * vmbus_onoffer_rescind - Rescind offer handler.
947 * We queue a work item to process this offer synchronously
949 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
951 struct vmbus_channel_rescind_offer *rescind;
952 struct vmbus_channel *channel;
955 rescind = (struct vmbus_channel_rescind_offer *)hdr;
957 trace_vmbus_onoffer_rescind(rescind);
960 * The offer msg and the corresponding rescind msg
961 * from the host are guranteed to be ordered -
962 * offer comes in first and then the rescind.
963 * Since we process these events in work elements,
964 * and with preemption, we may end up processing
965 * the events out of order. Given that we handle these
966 * work elements on the same CPU, this is possible only
967 * in the case of preemption. In any case wait here
968 * until the offer processing has moved beyond the
969 * point where the channel is discoverable.
972 while (atomic_read(&vmbus_connection.offer_in_progress) != 0) {
974 * We wait here until any channel offer is currently
980 mutex_lock(&vmbus_connection.channel_mutex);
981 channel = relid2channel(rescind->child_relid);
982 mutex_unlock(&vmbus_connection.channel_mutex);
984 if (channel == NULL) {
986 * We failed in processing the offer message;
987 * we would have cleaned up the relid in that
994 * Before setting channel->rescind in vmbus_rescind_cleanup(), we
995 * should make sure the channel callback is not running any more.
997 vmbus_reset_channel_cb(channel);
1000 * Now wait for offer handling to complete.
1002 vmbus_rescind_cleanup(channel);
1003 while (READ_ONCE(channel->probe_done) == false) {
1005 * We wait here until any channel offer is currently
1012 * At this point, the rescind handling can proceed safely.
1015 if (channel->device_obj) {
1016 if (channel->chn_rescind_callback) {
1017 channel->chn_rescind_callback(channel);
1021 * We will have to unregister this device from the
1024 dev = get_device(&channel->device_obj->device);
1026 vmbus_device_unregister(channel->device_obj);
1029 } else if (channel->primary_channel != NULL) {
1031 * Sub-channel is being rescinded. Following is the channel
1032 * close sequence when initiated from the driveri (refer to
1033 * vmbus_close() for details):
1034 * 1. Close all sub-channels first
1035 * 2. Then close the primary channel.
1037 mutex_lock(&vmbus_connection.channel_mutex);
1038 if (channel->state == CHANNEL_OPEN_STATE) {
1040 * The channel is currently not open;
1041 * it is safe for us to cleanup the channel.
1043 hv_process_channel_removal(rescind->child_relid);
1045 complete(&channel->rescind_event);
1047 mutex_unlock(&vmbus_connection.channel_mutex);
1051 void vmbus_hvsock_device_unregister(struct vmbus_channel *channel)
1053 BUG_ON(!is_hvsock_channel(channel));
1055 /* We always get a rescind msg when a connection is closed. */
1056 while (!READ_ONCE(channel->probe_done) || !READ_ONCE(channel->rescind))
1059 vmbus_device_unregister(channel->device_obj);
1061 EXPORT_SYMBOL_GPL(vmbus_hvsock_device_unregister);
1065 * vmbus_onoffers_delivered -
1066 * This is invoked when all offers have been delivered.
1068 * Nothing to do here.
1070 static void vmbus_onoffers_delivered(
1071 struct vmbus_channel_message_header *hdr)
1076 * vmbus_onopen_result - Open result handler.
1078 * This is invoked when we received a response to our channel open request.
1079 * Find the matching request, copy the response and signal the requesting
1082 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
1084 struct vmbus_channel_open_result *result;
1085 struct vmbus_channel_msginfo *msginfo;
1086 struct vmbus_channel_message_header *requestheader;
1087 struct vmbus_channel_open_channel *openmsg;
1088 unsigned long flags;
1090 result = (struct vmbus_channel_open_result *)hdr;
1092 trace_vmbus_onopen_result(result);
1095 * Find the open msg, copy the result and signal/unblock the wait event
1097 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1099 list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1102 (struct vmbus_channel_message_header *)msginfo->msg;
1104 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
1106 (struct vmbus_channel_open_channel *)msginfo->msg;
1107 if (openmsg->child_relid == result->child_relid &&
1108 openmsg->openid == result->openid) {
1109 memcpy(&msginfo->response.open_result,
1112 struct vmbus_channel_open_result));
1113 complete(&msginfo->waitevent);
1118 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1122 * vmbus_ongpadl_created - GPADL created handler.
1124 * This is invoked when we received a response to our gpadl create request.
1125 * Find the matching request, copy the response and signal the requesting
1128 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
1130 struct vmbus_channel_gpadl_created *gpadlcreated;
1131 struct vmbus_channel_msginfo *msginfo;
1132 struct vmbus_channel_message_header *requestheader;
1133 struct vmbus_channel_gpadl_header *gpadlheader;
1134 unsigned long flags;
1136 gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
1138 trace_vmbus_ongpadl_created(gpadlcreated);
1141 * Find the establish msg, copy the result and signal/unblock the wait
1144 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1146 list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1149 (struct vmbus_channel_message_header *)msginfo->msg;
1151 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
1153 (struct vmbus_channel_gpadl_header *)requestheader;
1155 if ((gpadlcreated->child_relid ==
1156 gpadlheader->child_relid) &&
1157 (gpadlcreated->gpadl == gpadlheader->gpadl)) {
1158 memcpy(&msginfo->response.gpadl_created,
1161 struct vmbus_channel_gpadl_created));
1162 complete(&msginfo->waitevent);
1167 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1171 * vmbus_ongpadl_torndown - GPADL torndown handler.
1173 * This is invoked when we received a response to our gpadl teardown request.
1174 * Find the matching request, copy the response and signal the requesting
1177 static void vmbus_ongpadl_torndown(
1178 struct vmbus_channel_message_header *hdr)
1180 struct vmbus_channel_gpadl_torndown *gpadl_torndown;
1181 struct vmbus_channel_msginfo *msginfo;
1182 struct vmbus_channel_message_header *requestheader;
1183 struct vmbus_channel_gpadl_teardown *gpadl_teardown;
1184 unsigned long flags;
1186 gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
1188 trace_vmbus_ongpadl_torndown(gpadl_torndown);
1191 * Find the open msg, copy the result and signal/unblock the wait event
1193 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1195 list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1198 (struct vmbus_channel_message_header *)msginfo->msg;
1200 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
1202 (struct vmbus_channel_gpadl_teardown *)requestheader;
1204 if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
1205 memcpy(&msginfo->response.gpadl_torndown,
1208 struct vmbus_channel_gpadl_torndown));
1209 complete(&msginfo->waitevent);
1214 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1218 * vmbus_onversion_response - Version response handler
1220 * This is invoked when we received a response to our initiate contact request.
1221 * Find the matching request, copy the response and signal the requesting
1224 static void vmbus_onversion_response(
1225 struct vmbus_channel_message_header *hdr)
1227 struct vmbus_channel_msginfo *msginfo;
1228 struct vmbus_channel_message_header *requestheader;
1229 struct vmbus_channel_version_response *version_response;
1230 unsigned long flags;
1232 version_response = (struct vmbus_channel_version_response *)hdr;
1234 trace_vmbus_onversion_response(version_response);
1236 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1238 list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1241 (struct vmbus_channel_message_header *)msginfo->msg;
1243 if (requestheader->msgtype ==
1244 CHANNELMSG_INITIATE_CONTACT) {
1245 memcpy(&msginfo->response.version_response,
1247 sizeof(struct vmbus_channel_version_response));
1248 complete(&msginfo->waitevent);
1251 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1254 /* Channel message dispatch table */
1255 const struct vmbus_channel_message_table_entry
1256 channel_message_table[CHANNELMSG_COUNT] = {
1257 { CHANNELMSG_INVALID, 0, NULL },
1258 { CHANNELMSG_OFFERCHANNEL, 0, vmbus_onoffer },
1259 { CHANNELMSG_RESCIND_CHANNELOFFER, 0, vmbus_onoffer_rescind },
1260 { CHANNELMSG_REQUESTOFFERS, 0, NULL },
1261 { CHANNELMSG_ALLOFFERS_DELIVERED, 1, vmbus_onoffers_delivered },
1262 { CHANNELMSG_OPENCHANNEL, 0, NULL },
1263 { CHANNELMSG_OPENCHANNEL_RESULT, 1, vmbus_onopen_result },
1264 { CHANNELMSG_CLOSECHANNEL, 0, NULL },
1265 { CHANNELMSG_GPADL_HEADER, 0, NULL },
1266 { CHANNELMSG_GPADL_BODY, 0, NULL },
1267 { CHANNELMSG_GPADL_CREATED, 1, vmbus_ongpadl_created },
1268 { CHANNELMSG_GPADL_TEARDOWN, 0, NULL },
1269 { CHANNELMSG_GPADL_TORNDOWN, 1, vmbus_ongpadl_torndown },
1270 { CHANNELMSG_RELID_RELEASED, 0, NULL },
1271 { CHANNELMSG_INITIATE_CONTACT, 0, NULL },
1272 { CHANNELMSG_VERSION_RESPONSE, 1, vmbus_onversion_response },
1273 { CHANNELMSG_UNLOAD, 0, NULL },
1274 { CHANNELMSG_UNLOAD_RESPONSE, 1, vmbus_unload_response },
1275 { CHANNELMSG_18, 0, NULL },
1276 { CHANNELMSG_19, 0, NULL },
1277 { CHANNELMSG_20, 0, NULL },
1278 { CHANNELMSG_TL_CONNECT_REQUEST, 0, NULL },
1279 { CHANNELMSG_22, 0, NULL },
1280 { CHANNELMSG_TL_CONNECT_RESULT, 0, NULL },
1284 * vmbus_onmessage - Handler for channel protocol messages.
1286 * This is invoked in the vmbus worker thread context.
1288 void vmbus_onmessage(void *context)
1290 struct hv_message *msg = context;
1291 struct vmbus_channel_message_header *hdr;
1293 hdr = (struct vmbus_channel_message_header *)msg->u.payload;
1295 trace_vmbus_on_message(hdr);
1298 * vmbus_on_msg_dpc() makes sure the hdr->msgtype here can not go
1299 * out of bound and the message_handler pointer can not be NULL.
1301 channel_message_table[hdr->msgtype].message_handler(hdr);
1305 * vmbus_request_offers - Send a request to get all our pending offers.
1307 int vmbus_request_offers(void)
1309 struct vmbus_channel_message_header *msg;
1310 struct vmbus_channel_msginfo *msginfo;
1313 msginfo = kmalloc(sizeof(*msginfo) +
1314 sizeof(struct vmbus_channel_message_header),
1319 msg = (struct vmbus_channel_message_header *)msginfo->msg;
1321 msg->msgtype = CHANNELMSG_REQUESTOFFERS;
1323 ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_message_header),
1326 trace_vmbus_request_offers(ret);
1329 pr_err("Unable to request offers - %d\n", ret);
1341 * Retrieve the (sub) channel on which to send an outgoing request.
1342 * When a primary channel has multiple sub-channels, we try to
1343 * distribute the load equally amongst all available channels.
1345 struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary)
1347 struct list_head *cur, *tmp;
1349 struct vmbus_channel *cur_channel;
1350 struct vmbus_channel *outgoing_channel = primary;
1354 if (list_empty(&primary->sc_list))
1355 return outgoing_channel;
1357 next_channel = primary->next_oc++;
1359 if (next_channel > (primary->num_sc)) {
1360 primary->next_oc = 0;
1361 return outgoing_channel;
1364 cur_cpu = hv_cpu_number_to_vp_number(smp_processor_id());
1365 list_for_each_safe(cur, tmp, &primary->sc_list) {
1366 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
1367 if (cur_channel->state != CHANNEL_OPENED_STATE)
1370 if (cur_channel->target_vp == cur_cpu)
1373 if (i == next_channel)
1379 return outgoing_channel;
1381 EXPORT_SYMBOL_GPL(vmbus_get_outgoing_channel);
1383 static void invoke_sc_cb(struct vmbus_channel *primary_channel)
1385 struct list_head *cur, *tmp;
1386 struct vmbus_channel *cur_channel;
1388 if (primary_channel->sc_creation_callback == NULL)
1391 list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
1392 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
1394 primary_channel->sc_creation_callback(cur_channel);
1398 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
1399 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
1401 primary_channel->sc_creation_callback = sc_cr_cb;
1403 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
1405 bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
1409 ret = !list_empty(&primary->sc_list);
1413 * Invoke the callback on sub-channel creation.
1414 * This will present a uniform interface to the
1417 invoke_sc_cb(primary);
1422 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);
1424 void vmbus_set_chn_rescind_callback(struct vmbus_channel *channel,
1425 void (*chn_rescind_cb)(struct vmbus_channel *))
1427 channel->chn_rescind_callback = chn_rescind_cb;
1429 EXPORT_SYMBOL_GPL(vmbus_set_chn_rescind_callback);