xref: /openbmc/linux/drivers/hv/hyperv_vmbus.h (revision 3e26a691)
1 /*
2  *
3  * Copyright (c) 2011, Microsoft Corporation.
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms and conditions of the GNU General Public License,
7  * version 2, as published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
12  * more details.
13  *
14  * You should have received a copy of the GNU General Public License along with
15  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
16  * Place - Suite 330, Boston, MA 02111-1307 USA.
17  *
18  * Authors:
19  *   Haiyang Zhang <haiyangz@microsoft.com>
20  *   Hank Janssen  <hjanssen@microsoft.com>
21  *   K. Y. Srinivasan <kys@microsoft.com>
22  *
23  */
24 
25 #ifndef _HYPERV_VMBUS_H
26 #define _HYPERV_VMBUS_H
27 
28 #include <linux/list.h>
29 #include <asm/sync_bitops.h>
30 #include <linux/atomic.h>
31 #include <linux/hyperv.h>
32 
33 /*
34  * Timeout for services such as KVP and fcopy.
35  */
36 #define HV_UTIL_TIMEOUT 30
37 
38 /*
39  * The below CPUID leaves are present if VersionAndFeatures.HypervisorPresent
40  * is set by CPUID(HVCPUID_VERSION_FEATURES).
41  */
42 enum hv_cpuid_function {
43 	HVCPUID_VERSION_FEATURES		= 0x00000001,
44 	HVCPUID_VENDOR_MAXFUNCTION		= 0x40000000,
45 	HVCPUID_INTERFACE			= 0x40000001,
46 
47 	/*
48 	 * The remaining functions depend on the value of
49 	 * HVCPUID_INTERFACE
50 	 */
51 	HVCPUID_VERSION			= 0x40000002,
52 	HVCPUID_FEATURES			= 0x40000003,
53 	HVCPUID_ENLIGHTENMENT_INFO	= 0x40000004,
54 	HVCPUID_IMPLEMENTATION_LIMITS		= 0x40000005,
55 };
56 
57 #define  HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE   0x400
58 
59 #define HV_X64_MSR_CRASH_P0   0x40000100
60 #define HV_X64_MSR_CRASH_P1   0x40000101
61 #define HV_X64_MSR_CRASH_P2   0x40000102
62 #define HV_X64_MSR_CRASH_P3   0x40000103
63 #define HV_X64_MSR_CRASH_P4   0x40000104
64 #define HV_X64_MSR_CRASH_CTL  0x40000105
65 
66 #define HV_CRASH_CTL_CRASH_NOTIFY (1ULL << 63)
67 
68 /* Define version of the synthetic interrupt controller. */
69 #define HV_SYNIC_VERSION		(1)
70 
71 #define HV_ANY_VP			(0xFFFFFFFF)
72 
73 /* Define synthetic interrupt controller flag constants. */
74 #define HV_EVENT_FLAGS_COUNT		(256 * 8)
75 #define HV_EVENT_FLAGS_BYTE_COUNT	(256)
76 #define HV_EVENT_FLAGS_DWORD_COUNT	(256 / sizeof(u32))
77 
78 /* Define invalid partition identifier. */
79 #define HV_PARTITION_ID_INVALID		((u64)0x0)
80 
81 /* Define port type. */
82 enum hv_port_type {
83 	HVPORT_MSG	= 1,
84 	HVPORT_EVENT		= 2,
85 	HVPORT_MONITOR	= 3
86 };
87 
88 /* Define port information structure. */
89 struct hv_port_info {
90 	enum hv_port_type port_type;
91 	u32 padding;
92 	union {
93 		struct {
94 			u32 target_sint;
95 			u32 target_vp;
96 			u64 rsvdz;
97 		} message_port_info;
98 		struct {
99 			u32 target_sint;
100 			u32 target_vp;
101 			u16 base_flag_number;
102 			u16 flag_count;
103 			u32 rsvdz;
104 		} event_port_info;
105 		struct {
106 			u64 monitor_address;
107 			u64 rsvdz;
108 		} monitor_port_info;
109 	};
110 };
111 
112 struct hv_connection_info {
113 	enum hv_port_type port_type;
114 	u32 padding;
115 	union {
116 		struct {
117 			u64 rsvdz;
118 		} message_connection_info;
119 		struct {
120 			u64 rsvdz;
121 		} event_connection_info;
122 		struct {
123 			u64 monitor_address;
124 		} monitor_connection_info;
125 	};
126 };
127 
128 /*
129  * Timer configuration register.
130  */
131 union hv_timer_config {
132 	u64 as_uint64;
133 	struct {
134 		u64 enable:1;
135 		u64 periodic:1;
136 		u64 lazy:1;
137 		u64 auto_enable:1;
138 		u64 reserved_z0:12;
139 		u64 sintx:4;
140 		u64 reserved_z1:44;
141 	};
142 };
143 
144 /* Define the number of message buffers associated with each port. */
145 #define HV_PORT_MESSAGE_BUFFER_COUNT	(16)
146 
147 /* Define the synthetic interrupt controller event flags format. */
148 union hv_synic_event_flags {
149 	u8 flags8[HV_EVENT_FLAGS_BYTE_COUNT];
150 	u32 flags32[HV_EVENT_FLAGS_DWORD_COUNT];
151 };
152 
153 /* Define the synthetic interrupt flags page layout. */
154 struct hv_synic_event_flags_page {
155 	union hv_synic_event_flags sintevent_flags[HV_SYNIC_SINT_COUNT];
156 };
157 
158 /* Define SynIC control register. */
159 union hv_synic_scontrol {
160 	u64 as_uint64;
161 	struct {
162 		u64 enable:1;
163 		u64 reserved:63;
164 	};
165 };
166 
167 /* Define synthetic interrupt source. */
168 union hv_synic_sint {
169 	u64 as_uint64;
170 	struct {
171 		u64 vector:8;
172 		u64 reserved1:8;
173 		u64 masked:1;
174 		u64 auto_eoi:1;
175 		u64 reserved2:46;
176 	};
177 };
178 
179 /* Define the format of the SIMP register */
180 union hv_synic_simp {
181 	u64 as_uint64;
182 	struct {
183 		u64 simp_enabled:1;
184 		u64 preserved:11;
185 		u64 base_simp_gpa:52;
186 	};
187 };
188 
189 /* Define the format of the SIEFP register */
190 union hv_synic_siefp {
191 	u64 as_uint64;
192 	struct {
193 		u64 siefp_enabled:1;
194 		u64 preserved:11;
195 		u64 base_siefp_gpa:52;
196 	};
197 };
198 
199 /* Definitions for the monitored notification facility */
200 union hv_monitor_trigger_group {
201 	u64 as_uint64;
202 	struct {
203 		u32 pending;
204 		u32 armed;
205 	};
206 };
207 
208 struct hv_monitor_parameter {
209 	union hv_connection_id connectionid;
210 	u16 flagnumber;
211 	u16 rsvdz;
212 };
213 
214 union hv_monitor_trigger_state {
215 	u32 asu32;
216 
217 	struct {
218 		u32 group_enable:4;
219 		u32 rsvdz:28;
220 	};
221 };
222 
223 /* struct hv_monitor_page Layout */
224 /* ------------------------------------------------------ */
225 /* | 0   | TriggerState (4 bytes) | Rsvd1 (4 bytes)     | */
226 /* | 8   | TriggerGroup[0]                              | */
227 /* | 10  | TriggerGroup[1]                              | */
228 /* | 18  | TriggerGroup[2]                              | */
229 /* | 20  | TriggerGroup[3]                              | */
230 /* | 28  | Rsvd2[0]                                     | */
231 /* | 30  | Rsvd2[1]                                     | */
232 /* | 38  | Rsvd2[2]                                     | */
233 /* | 40  | NextCheckTime[0][0]    | NextCheckTime[0][1] | */
234 /* | ...                                                | */
235 /* | 240 | Latency[0][0..3]                             | */
236 /* | 340 | Rsvz3[0]                                     | */
237 /* | 440 | Parameter[0][0]                              | */
238 /* | 448 | Parameter[0][1]                              | */
239 /* | ...                                                | */
240 /* | 840 | Rsvd4[0]                                     | */
241 /* ------------------------------------------------------ */
242 struct hv_monitor_page {
243 	union hv_monitor_trigger_state trigger_state;
244 	u32 rsvdz1;
245 
246 	union hv_monitor_trigger_group trigger_group[4];
247 	u64 rsvdz2[3];
248 
249 	s32 next_checktime[4][32];
250 
251 	u16 latency[4][32];
252 	u64 rsvdz3[32];
253 
254 	struct hv_monitor_parameter parameter[4][32];
255 
256 	u8 rsvdz4[1984];
257 };
258 
259 /* Definition of the hv_post_message hypercall input structure. */
260 struct hv_input_post_message {
261 	union hv_connection_id connectionid;
262 	u32 reserved;
263 	u32 message_type;
264 	u32 payload_size;
265 	u64 payload[HV_MESSAGE_PAYLOAD_QWORD_COUNT];
266 };
267 
268 /*
269  * Versioning definitions used for guests reporting themselves to the
270  * hypervisor, and visa versa.
271  */
272 
273 /* Version info reported by guest OS's */
274 enum hv_guest_os_vendor {
275 	HVGUESTOS_VENDOR_MICROSOFT	= 0x0001
276 };
277 
278 enum hv_guest_os_microsoft_ids {
279 	HVGUESTOS_MICROSOFT_UNDEFINED	= 0x00,
280 	HVGUESTOS_MICROSOFT_MSDOS		= 0x01,
281 	HVGUESTOS_MICROSOFT_WINDOWS3X	= 0x02,
282 	HVGUESTOS_MICROSOFT_WINDOWS9X	= 0x03,
283 	HVGUESTOS_MICROSOFT_WINDOWSNT	= 0x04,
284 	HVGUESTOS_MICROSOFT_WINDOWSCE	= 0x05
285 };
286 
287 /*
288  * Declare the MSR used to identify the guest OS.
289  */
290 #define HV_X64_MSR_GUEST_OS_ID	0x40000000
291 
292 union hv_x64_msr_guest_os_id_contents {
293 	u64 as_uint64;
294 	struct {
295 		u64 build_number:16;
296 		u64 service_version:8; /* Service Pack, etc. */
297 		u64 minor_version:8;
298 		u64 major_version:8;
299 		u64 os_id:8; /* enum hv_guest_os_microsoft_ids (if Vendor=MS) */
300 		u64 vendor_id:16; /* enum hv_guest_os_vendor */
301 	};
302 };
303 
304 /*
305  * Declare the MSR used to setup pages used to communicate with the hypervisor.
306  */
307 #define HV_X64_MSR_HYPERCALL	0x40000001
308 
309 union hv_x64_msr_hypercall_contents {
310 	u64 as_uint64;
311 	struct {
312 		u64 enable:1;
313 		u64 reserved:11;
314 		u64 guest_physical_address:52;
315 	};
316 };
317 
318 
319 enum {
320 	VMBUS_MESSAGE_CONNECTION_ID	= 1,
321 	VMBUS_MESSAGE_PORT_ID		= 1,
322 	VMBUS_EVENT_CONNECTION_ID	= 2,
323 	VMBUS_EVENT_PORT_ID		= 2,
324 	VMBUS_MONITOR_CONNECTION_ID	= 3,
325 	VMBUS_MONITOR_PORT_ID		= 3,
326 	VMBUS_MESSAGE_SINT		= 2,
327 };
328 
329 /* #defines */
330 
331 #define HV_PRESENT_BIT			0x80000000
332 
333 /*
334  * The guest OS needs to register the guest ID with the hypervisor.
335  * The guest ID is a 64 bit entity and the structure of this ID is
336  * specified in the Hyper-V specification:
337  *
338  * http://msdn.microsoft.com/en-us/library/windows/hardware/ff542653%28v=vs.85%29.aspx
339  *
340  * While the current guideline does not specify how Linux guest ID(s)
341  * need to be generated, our plan is to publish the guidelines for
342  * Linux and other guest operating systems that currently are hosted
343  * on Hyper-V. The implementation here conforms to this yet
344  * unpublished guidelines.
345  *
346  *
347  * Bit(s)
348  * 63 - Indicates if the OS is Open Source or not; 1 is Open Source
349  * 62:56 - Os Type; Linux is 0x100
350  * 55:48 - Distro specific identification
351  * 47:16 - Linux kernel version number
352  * 15:0  - Distro specific identification
353  *
354  *
355  */
356 
357 #define HV_LINUX_VENDOR_ID		0x8100
358 
359 /*
360  * Generate the guest ID based on the guideline described above.
361  */
362 
363 static inline  __u64 generate_guest_id(__u8 d_info1, __u32 kernel_version,
364 					__u16 d_info2)
365 {
366 	__u64 guest_id = 0;
367 
368 	guest_id = (((__u64)HV_LINUX_VENDOR_ID) << 48);
369 	guest_id |= (((__u64)(d_info1)) << 48);
370 	guest_id |= (((__u64)(kernel_version)) << 16);
371 	guest_id |= ((__u64)(d_info2));
372 
373 	return guest_id;
374 }
375 
376 
377 #define HV_CPU_POWER_MANAGEMENT		(1 << 0)
378 #define HV_RECOMMENDATIONS_MAX		4
379 
380 #define HV_X64_MAX			5
381 #define HV_CAPS_MAX			8
382 
383 
384 #define HV_HYPERCALL_PARAM_ALIGN	sizeof(u64)
385 
386 
387 /* Service definitions */
388 
389 #define HV_SERVICE_PARENT_PORT				(0)
390 #define HV_SERVICE_PARENT_CONNECTION			(0)
391 
392 #define HV_SERVICE_CONNECT_RESPONSE_SUCCESS		(0)
393 #define HV_SERVICE_CONNECT_RESPONSE_INVALID_PARAMETER	(1)
394 #define HV_SERVICE_CONNECT_RESPONSE_UNKNOWN_SERVICE	(2)
395 #define HV_SERVICE_CONNECT_RESPONSE_CONNECTION_REJECTED	(3)
396 
397 #define HV_SERVICE_CONNECT_REQUEST_MESSAGE_ID		(1)
398 #define HV_SERVICE_CONNECT_RESPONSE_MESSAGE_ID		(2)
399 #define HV_SERVICE_DISCONNECT_REQUEST_MESSAGE_ID	(3)
400 #define HV_SERVICE_DISCONNECT_RESPONSE_MESSAGE_ID	(4)
401 #define HV_SERVICE_MAX_MESSAGE_ID				(4)
402 
403 #define HV_SERVICE_PROTOCOL_VERSION (0x0010)
404 #define HV_CONNECT_PAYLOAD_BYTE_COUNT 64
405 
406 /* #define VMBUS_REVISION_NUMBER	6 */
407 
408 /* Our local vmbus's port and connection id. Anything >0 is fine */
409 /* #define VMBUS_PORT_ID		11 */
410 
411 /* 628180B8-308D-4c5e-B7DB-1BEB62E62EF4 */
412 static const uuid_le VMBUS_SERVICE_ID = {
413 	.b = {
414 		0xb8, 0x80, 0x81, 0x62, 0x8d, 0x30, 0x5e, 0x4c,
415 		0xb7, 0xdb, 0x1b, 0xeb, 0x62, 0xe6, 0x2e, 0xf4
416 	},
417 };
418 
419 
420 
421 struct hv_context {
422 	/* We only support running on top of Hyper-V
423 	* So at this point this really can only contain the Hyper-V ID
424 	*/
425 	u64 guestid;
426 
427 	void *hypercall_page;
428 	void *tsc_page;
429 
430 	bool synic_initialized;
431 
432 	void *synic_message_page[NR_CPUS];
433 	void *synic_event_page[NR_CPUS];
434 	/*
435 	 * Hypervisor's notion of virtual processor ID is different from
436 	 * Linux' notion of CPU ID. This information can only be retrieved
437 	 * in the context of the calling CPU. Setup a map for easy access
438 	 * to this information:
439 	 *
440 	 * vp_index[a] is the Hyper-V's processor ID corresponding to
441 	 * Linux cpuid 'a'.
442 	 */
443 	u32 vp_index[NR_CPUS];
444 	/*
445 	 * Starting with win8, we can take channel interrupts on any CPU;
446 	 * we will manage the tasklet that handles events messages on a per CPU
447 	 * basis.
448 	 */
449 	struct tasklet_struct *event_dpc[NR_CPUS];
450 	struct tasklet_struct *msg_dpc[NR_CPUS];
451 	/*
452 	 * To optimize the mapping of relid to channel, maintain
453 	 * per-cpu list of the channels based on their CPU affinity.
454 	 */
455 	struct list_head percpu_list[NR_CPUS];
456 	/*
457 	 * buffer to post messages to the host.
458 	 */
459 	void *post_msg_page[NR_CPUS];
460 	/*
461 	 * Support PV clockevent device.
462 	 */
463 	struct clock_event_device *clk_evt[NR_CPUS];
464 	/*
465 	 * To manage allocations in a NUMA node.
466 	 * Array indexed by numa node ID.
467 	 */
468 	struct cpumask *hv_numa_map;
469 };
470 
471 extern struct hv_context hv_context;
472 
473 struct ms_hyperv_tsc_page {
474 	volatile u32 tsc_sequence;
475 	u32 reserved1;
476 	volatile u64 tsc_scale;
477 	volatile s64 tsc_offset;
478 	u64 reserved2[509];
479 };
480 
481 struct hv_ring_buffer_debug_info {
482 	u32 current_interrupt_mask;
483 	u32 current_read_index;
484 	u32 current_write_index;
485 	u32 bytes_avail_toread;
486 	u32 bytes_avail_towrite;
487 };
488 
489 /* Hv Interface */
490 
491 extern int hv_init(void);
492 
493 extern void hv_cleanup(void);
494 
495 extern int hv_post_message(union hv_connection_id connection_id,
496 			 enum hv_message_type message_type,
497 			 void *payload, size_t payload_size);
498 
499 extern int hv_synic_alloc(void);
500 
501 extern void hv_synic_free(void);
502 
503 extern void hv_synic_init(void *irqarg);
504 
505 extern void hv_synic_cleanup(void *arg);
506 
507 extern void hv_synic_clockevents_cleanup(void);
508 
509 /*
510  * Host version information.
511  */
512 extern unsigned int host_info_eax;
513 extern unsigned int host_info_ebx;
514 extern unsigned int host_info_ecx;
515 extern unsigned int host_info_edx;
516 
517 /* Interface */
518 
519 
520 int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info, void *buffer,
521 		   u32 buflen);
522 
523 void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info);
524 
525 int hv_ringbuffer_write(struct hv_ring_buffer_info *ring_info,
526 		    struct kvec *kv_list,
527 		    u32 kv_count, bool *signal, bool lock);
528 
529 int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info,
530 		       void *buffer, u32 buflen, u32 *buffer_actual_len,
531 		       u64 *requestid, bool *signal, bool raw);
532 
533 void hv_ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info,
534 			    struct hv_ring_buffer_debug_info *debug_info);
535 
536 void hv_begin_read(struct hv_ring_buffer_info *rbi);
537 
538 u32 hv_end_read(struct hv_ring_buffer_info *rbi);
539 
540 /*
541  * Maximum channels is determined by the size of the interrupt page
542  * which is PAGE_SIZE. 1/2 of PAGE_SIZE is for send endpoint interrupt
543  * and the other is receive endpoint interrupt
544  */
545 #define MAX_NUM_CHANNELS	((PAGE_SIZE >> 1) << 3)	/* 16348 channels */
546 
547 /* The value here must be in multiple of 32 */
548 /* TODO: Need to make this configurable */
549 #define MAX_NUM_CHANNELS_SUPPORTED	256
550 
551 
552 enum vmbus_connect_state {
553 	DISCONNECTED,
554 	CONNECTING,
555 	CONNECTED,
556 	DISCONNECTING
557 };
558 
559 #define MAX_SIZE_CHANNEL_MESSAGE	HV_MESSAGE_PAYLOAD_BYTE_COUNT
560 
561 struct vmbus_connection {
562 	enum vmbus_connect_state conn_state;
563 
564 	atomic_t next_gpadl_handle;
565 
566 	struct completion  unload_event;
567 	/*
568 	 * Represents channel interrupts. Each bit position represents a
569 	 * channel.  When a channel sends an interrupt via VMBUS, it finds its
570 	 * bit in the sendInterruptPage, set it and calls Hv to generate a port
571 	 * event. The other end receives the port event and parse the
572 	 * recvInterruptPage to see which bit is set
573 	 */
574 	void *int_page;
575 	void *send_int_page;
576 	void *recv_int_page;
577 
578 	/*
579 	 * 2 pages - 1st page for parent->child notification and 2nd
580 	 * is child->parent notification
581 	 */
582 	struct hv_monitor_page *monitor_pages[2];
583 	struct list_head chn_msg_list;
584 	spinlock_t channelmsg_lock;
585 
586 	/* List of channels */
587 	struct list_head chn_list;
588 	struct mutex channel_mutex;
589 
590 	struct workqueue_struct *work_queue;
591 };
592 
593 
594 struct vmbus_msginfo {
595 	/* Bookkeeping stuff */
596 	struct list_head msglist_entry;
597 
598 	/* The message itself */
599 	unsigned char msg[0];
600 };
601 
602 
603 extern struct vmbus_connection vmbus_connection;
604 
605 enum vmbus_message_handler_type {
606 	/* The related handler can sleep. */
607 	VMHT_BLOCKING = 0,
608 
609 	/* The related handler must NOT sleep. */
610 	VMHT_NON_BLOCKING = 1,
611 };
612 
613 struct vmbus_channel_message_table_entry {
614 	enum vmbus_channel_message_type message_type;
615 	enum vmbus_message_handler_type handler_type;
616 	void (*message_handler)(struct vmbus_channel_message_header *msg);
617 };
618 
619 extern struct vmbus_channel_message_table_entry
620 	channel_message_table[CHANNELMSG_COUNT];
621 
622 /* Free the message slot and signal end-of-message if required */
623 static inline void vmbus_signal_eom(struct hv_message *msg)
624 {
625 	msg->header.message_type = HVMSG_NONE;
626 
627 	/*
628 	 * Make sure the write to MessageType (ie set to
629 	 * HVMSG_NONE) happens before we read the
630 	 * MessagePending and EOMing. Otherwise, the EOMing
631 	 * will not deliver any more messages since there is
632 	 * no empty slot
633 	 */
634 	mb();
635 
636 	if (msg->header.message_flags.msg_pending) {
637 		/*
638 		 * This will cause message queue rescan to
639 		 * possibly deliver another msg from the
640 		 * hypervisor
641 		 */
642 		wrmsrl(HV_X64_MSR_EOM, 0);
643 	}
644 }
645 
646 /* General vmbus interface */
647 
648 struct hv_device *vmbus_device_create(const uuid_le *type,
649 				      const uuid_le *instance,
650 				      struct vmbus_channel *channel);
651 
652 int vmbus_device_register(struct hv_device *child_device_obj);
653 void vmbus_device_unregister(struct hv_device *device_obj);
654 
655 /* static void */
656 /* VmbusChildDeviceDestroy( */
657 /* struct hv_device *); */
658 
659 struct vmbus_channel *relid2channel(u32 relid);
660 
661 void vmbus_free_channels(void);
662 
663 /* Connection interface */
664 
665 int vmbus_connect(void);
666 void vmbus_disconnect(void);
667 
668 int vmbus_post_msg(void *buffer, size_t buflen);
669 
670 void vmbus_set_event(struct vmbus_channel *channel);
671 
672 void vmbus_on_event(unsigned long data);
673 void vmbus_on_msg_dpc(unsigned long data);
674 
675 int hv_kvp_init(struct hv_util_service *);
676 void hv_kvp_deinit(void);
677 void hv_kvp_onchannelcallback(void *);
678 
679 int hv_vss_init(struct hv_util_service *);
680 void hv_vss_deinit(void);
681 void hv_vss_onchannelcallback(void *);
682 
683 int hv_fcopy_init(struct hv_util_service *);
684 void hv_fcopy_deinit(void);
685 void hv_fcopy_onchannelcallback(void *);
686 void vmbus_initiate_unload(bool crash);
687 
688 static inline void hv_poll_channel(struct vmbus_channel *channel,
689 				   void (*cb)(void *))
690 {
691 	if (!channel)
692 		return;
693 
694 	smp_call_function_single(channel->target_cpu, cb, channel, true);
695 }
696 
697 enum hvutil_device_state {
698 	HVUTIL_DEVICE_INIT = 0,  /* driver is loaded, waiting for userspace */
699 	HVUTIL_READY,            /* userspace is registered */
700 	HVUTIL_HOSTMSG_RECEIVED, /* message from the host was received */
701 	HVUTIL_USERSPACE_REQ,    /* request to userspace was sent */
702 	HVUTIL_USERSPACE_RECV,   /* reply from userspace was received */
703 	HVUTIL_DEVICE_DYING,     /* driver unload is in progress */
704 };
705 
706 #endif /* _HYPERV_VMBUS_H */
707