1 // SPDX-License-Identifier: GPL-2.0-only
4 * Copyright (c) 2009, Microsoft Corporation.
7 * Haiyang Zhang <haiyangz@microsoft.com>
8 * Hank Janssen <hjanssen@microsoft.com>
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12 #include <linux/kernel.h>
13 #include <linux/sched.h>
14 #include <linux/wait.h>
15 #include <linux/delay.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/vmalloc.h>
20 #include <linux/hyperv.h>
21 #include <linux/export.h>
22 #include <asm/mshyperv.h>
24 #include "hyperv_vmbus.h"
27 struct vmbus_connection vmbus_connection
= {
28 .conn_state
= DISCONNECTED
,
29 .unload_event
= COMPLETION_INITIALIZER(
30 vmbus_connection
.unload_event
),
31 .next_gpadl_handle
= ATOMIC_INIT(0xE1E10),
33 .ready_for_suspend_event
= COMPLETION_INITIALIZER(
34 vmbus_connection
.ready_for_suspend_event
),
35 .ready_for_resume_event
= COMPLETION_INITIALIZER(
36 vmbus_connection
.ready_for_resume_event
),
38 EXPORT_SYMBOL_GPL(vmbus_connection
);
41 * Negotiated protocol version with the host.
43 __u32 vmbus_proto_version
;
44 EXPORT_SYMBOL_GPL(vmbus_proto_version
);
47 * Table of VMBus versions listed from newest to oldest.
49 static __u32 vmbus_versions
[] = {
63 * Maximal VMBus protocol version guests can negotiate. Useful to cap the
64 * VMBus version for testing and debugging purpose.
66 static uint max_version
= VERSION_WIN10_V5_3
;
68 module_param(max_version
, uint
, S_IRUGO
);
69 MODULE_PARM_DESC(max_version
,
70 "Maximal VMBus protocol version which can be negotiated");
72 int vmbus_negotiate_version(struct vmbus_channel_msginfo
*msginfo
, u32 version
)
75 struct vmbus_channel_initiate_contact
*msg
;
78 init_completion(&msginfo
->waitevent
);
80 msg
= (struct vmbus_channel_initiate_contact
*)msginfo
->msg
;
82 memset(msg
, 0, sizeof(*msg
));
83 msg
->header
.msgtype
= CHANNELMSG_INITIATE_CONTACT
;
84 msg
->vmbus_version_requested
= version
;
87 * VMBus protocol 5.0 (VERSION_WIN10_V5) and higher require that we must
88 * use VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,
89 * and for subsequent messages, we must use the Message Connection ID
90 * field in the host-returned Version Response Message. And, with
91 * VERSION_WIN10_V5 and higher, we don't use msg->interrupt_page, but we
92 * tell the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for
95 * On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1).
97 if (version
>= VERSION_WIN10_V5
) {
98 msg
->msg_sint
= VMBUS_MESSAGE_SINT
;
99 vmbus_connection
.msg_conn_id
= VMBUS_MESSAGE_CONNECTION_ID_4
;
101 msg
->interrupt_page
= virt_to_phys(vmbus_connection
.int_page
);
102 vmbus_connection
.msg_conn_id
= VMBUS_MESSAGE_CONNECTION_ID
;
105 msg
->monitor_page1
= virt_to_phys(vmbus_connection
.monitor_pages
[0]);
106 msg
->monitor_page2
= virt_to_phys(vmbus_connection
.monitor_pages
[1]);
107 msg
->target_vcpu
= hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU
);
110 * Add to list before we send the request since we may
111 * receive the response before returning from this routine
113 spin_lock_irqsave(&vmbus_connection
.channelmsg_lock
, flags
);
114 list_add_tail(&msginfo
->msglistentry
,
115 &vmbus_connection
.chn_msg_list
);
117 spin_unlock_irqrestore(&vmbus_connection
.channelmsg_lock
, flags
);
119 ret
= vmbus_post_msg(msg
,
120 sizeof(struct vmbus_channel_initiate_contact
),
123 trace_vmbus_negotiate_version(msg
, ret
);
126 spin_lock_irqsave(&vmbus_connection
.channelmsg_lock
, flags
);
127 list_del(&msginfo
->msglistentry
);
128 spin_unlock_irqrestore(&vmbus_connection
.channelmsg_lock
,
133 /* Wait for the connection response */
134 wait_for_completion(&msginfo
->waitevent
);
136 spin_lock_irqsave(&vmbus_connection
.channelmsg_lock
, flags
);
137 list_del(&msginfo
->msglistentry
);
138 spin_unlock_irqrestore(&vmbus_connection
.channelmsg_lock
, flags
);
140 /* Check if successful */
141 if (msginfo
->response
.version_response
.version_supported
) {
142 vmbus_connection
.conn_state
= CONNECTED
;
144 if (version
>= VERSION_WIN10_V5
)
145 vmbus_connection
.msg_conn_id
=
146 msginfo
->response
.version_response
.msg_conn_id
;
148 return -ECONNREFUSED
;
155 * vmbus_connect - Sends a connect request on the partition service connection
157 int vmbus_connect(void)
159 struct vmbus_channel_msginfo
*msginfo
= NULL
;
163 /* Initialize the vmbus connection */
164 vmbus_connection
.conn_state
= CONNECTING
;
165 vmbus_connection
.work_queue
= create_workqueue("hv_vmbus_con");
166 if (!vmbus_connection
.work_queue
) {
171 vmbus_connection
.handle_primary_chan_wq
=
172 create_workqueue("hv_pri_chan");
173 if (!vmbus_connection
.handle_primary_chan_wq
) {
178 vmbus_connection
.handle_sub_chan_wq
=
179 create_workqueue("hv_sub_chan");
180 if (!vmbus_connection
.handle_sub_chan_wq
) {
185 INIT_LIST_HEAD(&vmbus_connection
.chn_msg_list
);
186 spin_lock_init(&vmbus_connection
.channelmsg_lock
);
188 INIT_LIST_HEAD(&vmbus_connection
.chn_list
);
189 mutex_init(&vmbus_connection
.channel_mutex
);
192 * Setup the vmbus event connection for channel interrupt
195 vmbus_connection
.int_page
=
196 (void *)hv_alloc_hyperv_zeroed_page();
197 if (vmbus_connection
.int_page
== NULL
) {
202 vmbus_connection
.recv_int_page
= vmbus_connection
.int_page
;
203 vmbus_connection
.send_int_page
=
204 (void *)((unsigned long)vmbus_connection
.int_page
+
205 (HV_HYP_PAGE_SIZE
>> 1));
208 * Setup the monitor notification facility. The 1st page for
209 * parent->child and the 2nd page for child->parent
211 vmbus_connection
.monitor_pages
[0] = (void *)hv_alloc_hyperv_zeroed_page();
212 vmbus_connection
.monitor_pages
[1] = (void *)hv_alloc_hyperv_zeroed_page();
213 if ((vmbus_connection
.monitor_pages
[0] == NULL
) ||
214 (vmbus_connection
.monitor_pages
[1] == NULL
)) {
219 msginfo
= kzalloc(sizeof(*msginfo
) +
220 sizeof(struct vmbus_channel_initiate_contact
),
222 if (msginfo
== NULL
) {
228 * Negotiate a compatible VMBUS version number with the
229 * host. We start with the highest number we can support
230 * and work our way down until we negotiate a compatible
235 if (i
== ARRAY_SIZE(vmbus_versions
)) {
240 version
= vmbus_versions
[i
];
241 if (version
> max_version
)
244 ret
= vmbus_negotiate_version(msginfo
, version
);
245 if (ret
== -ETIMEDOUT
)
248 if (vmbus_connection
.conn_state
== CONNECTED
)
252 if (hv_is_isolation_supported() && version
< VERSION_WIN10_V5_2
) {
253 pr_err("Invalid VMBus version %d.%d (expected >= %d.%d) from the host supporting isolation\n",
254 version
>> 16, version
& 0xFFFF, VERSION_WIN10_V5_2
>> 16, VERSION_WIN10_V5_2
& 0xFFFF);
259 vmbus_proto_version
= version
;
260 pr_info("Vmbus version:%d.%d\n",
261 version
>> 16, version
& 0xFFFF);
263 vmbus_connection
.channels
= kcalloc(MAX_CHANNEL_RELIDS
,
264 sizeof(struct vmbus_channel
*),
266 if (vmbus_connection
.channels
== NULL
) {
275 pr_err("Unable to connect to host\n");
277 vmbus_connection
.conn_state
= DISCONNECTED
;
285 void vmbus_disconnect(void)
288 * First send the unload request to the host.
290 vmbus_initiate_unload(false);
292 if (vmbus_connection
.handle_sub_chan_wq
)
293 destroy_workqueue(vmbus_connection
.handle_sub_chan_wq
);
295 if (vmbus_connection
.handle_primary_chan_wq
)
296 destroy_workqueue(vmbus_connection
.handle_primary_chan_wq
);
298 if (vmbus_connection
.work_queue
)
299 destroy_workqueue(vmbus_connection
.work_queue
);
301 if (vmbus_connection
.int_page
) {
302 hv_free_hyperv_page((unsigned long)vmbus_connection
.int_page
);
303 vmbus_connection
.int_page
= NULL
;
306 hv_free_hyperv_page((unsigned long)vmbus_connection
.monitor_pages
[0]);
307 hv_free_hyperv_page((unsigned long)vmbus_connection
.monitor_pages
[1]);
308 vmbus_connection
.monitor_pages
[0] = NULL
;
309 vmbus_connection
.monitor_pages
[1] = NULL
;
313 * relid2channel - Get the channel object given its
314 * child relative id (ie channel id)
316 struct vmbus_channel
*relid2channel(u32 relid
)
318 if (WARN_ON(relid
>= MAX_CHANNEL_RELIDS
))
320 return READ_ONCE(vmbus_connection
.channels
[relid
]);
324 * vmbus_on_event - Process a channel event notification
326 * For batched channels (default) optimize host to guest signaling
328 * 1. While reading the channel, we disable interrupts from host.
329 * 2. Ensure that we process all posted messages from the host
330 * before returning from this callback.
331 * 3. Once we return, enable signaling from the host. Once this
332 * state is set we check to see if additional packets are
333 * available to read. In this case we repeat the process.
334 * If this tasklet has been running for a long time
335 * then reschedule ourselves.
337 void vmbus_on_event(unsigned long data
)
339 struct vmbus_channel
*channel
= (void *) data
;
340 unsigned long time_limit
= jiffies
+ 2;
342 trace_vmbus_on_event(channel
);
344 hv_debug_delay_test(channel
, INTERRUPT_DELAY
);
346 void (*callback_fn
)(void *);
348 /* A channel once created is persistent even when
349 * there is no driver handling the device. An
350 * unloading driver sets the onchannel_callback to NULL.
352 callback_fn
= READ_ONCE(channel
->onchannel_callback
);
353 if (unlikely(callback_fn
== NULL
))
356 (*callback_fn
)(channel
->channel_callback_context
);
358 if (channel
->callback_mode
!= HV_CALL_BATCHED
)
361 if (likely(hv_end_read(&channel
->inbound
) == 0))
364 hv_begin_read(&channel
->inbound
);
365 } while (likely(time_before(jiffies
, time_limit
)));
367 /* The time limit (2 jiffies) has been reached */
368 tasklet_schedule(&channel
->callback_event
);
372 * vmbus_post_msg - Send a msg on the vmbus's message connection
374 int vmbus_post_msg(void *buffer
, size_t buflen
, bool can_sleep
)
376 struct vmbus_channel_message_header
*hdr
;
377 union hv_connection_id conn_id
;
383 conn_id
.u
.id
= vmbus_connection
.msg_conn_id
;
386 * hv_post_message() can have transient failures because of
387 * insufficient resources. Retry the operation a couple of
388 * times before giving up.
390 while (retries
< 100) {
391 ret
= hv_post_message(conn_id
, 1, buffer
, buflen
);
394 case HV_STATUS_INVALID_CONNECTION_ID
:
396 * See vmbus_negotiate_version(): VMBus protocol 5.0
397 * and higher require that we must use
398 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
399 * Contact message, but on old hosts that only
400 * support VMBus protocol 4.0 or lower, here we get
401 * HV_STATUS_INVALID_CONNECTION_ID and we should
402 * return an error immediately without retrying.
405 if (hdr
->msgtype
== CHANNELMSG_INITIATE_CONTACT
)
408 * We could get this if we send messages too
413 case HV_STATUS_INSUFFICIENT_MEMORY
:
414 case HV_STATUS_INSUFFICIENT_BUFFERS
:
417 case HV_STATUS_SUCCESS
:
420 pr_err("hv_post_msg() failed; error code:%d\n", ret
);
425 if (can_sleep
&& usec
> 1000)
427 else if (usec
< MAX_UDELAY_MS
* 1000)
439 * vmbus_set_event - Send an event notification to the parent
441 void vmbus_set_event(struct vmbus_channel
*channel
)
443 u32 child_relid
= channel
->offermsg
.child_relid
;
445 if (!channel
->is_dedicated_interrupt
)
446 vmbus_send_interrupt(child_relid
);
448 ++channel
->sig_events
;
450 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT
, channel
->sig_event
);
452 EXPORT_SYMBOL_GPL(vmbus_set_event
);