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>
23 #include <linux/set_memory.h>
24 #include <asm/mshyperv.h>
26 #include "hyperv_vmbus.h"
29 struct vmbus_connection vmbus_connection = {
30 .conn_state = DISCONNECTED,
31 .unload_event = COMPLETION_INITIALIZER(
32 vmbus_connection.unload_event),
33 .next_gpadl_handle = ATOMIC_INIT(0xE1E10),
35 .ready_for_suspend_event = COMPLETION_INITIALIZER(
36 vmbus_connection.ready_for_suspend_event),
37 .ready_for_resume_event = COMPLETION_INITIALIZER(
38 vmbus_connection.ready_for_resume_event),
40 EXPORT_SYMBOL_GPL(vmbus_connection);
43 * Negotiated protocol version with the host.
45 __u32 vmbus_proto_version;
46 EXPORT_SYMBOL_GPL(vmbus_proto_version);
49 * Table of VMBus versions listed from newest to oldest.
50 * VERSION_WIN7 and VERSION_WS2008 are no longer supported in
51 * Linux guests and are not listed.
53 static __u32 vmbus_versions[] = {
65 * Maximal VMBus protocol version guests can negotiate. Useful to cap the
66 * VMBus version for testing and debugging purpose.
68 static uint max_version = VERSION_WIN10_V5_3;
70 module_param(max_version, uint, S_IRUGO);
71 MODULE_PARM_DESC(max_version,
72 "Maximal VMBus protocol version which can be negotiated");
74 int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
77 struct vmbus_channel_initiate_contact *msg;
80 init_completion(&msginfo->waitevent);
82 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
84 memset(msg, 0, sizeof(*msg));
85 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
86 msg->vmbus_version_requested = version;
89 * VMBus protocol 5.0 (VERSION_WIN10_V5) and higher require that we must
90 * use VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,
91 * and for subsequent messages, we must use the Message Connection ID
92 * field in the host-returned Version Response Message. And, with
93 * VERSION_WIN10_V5 and higher, we don't use msg->interrupt_page, but we
94 * tell the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for
97 * On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1).
99 if (version >= VERSION_WIN10_V5) {
100 msg->msg_sint = VMBUS_MESSAGE_SINT;
101 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
103 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
104 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID;
108 * shared_gpa_boundary is zero in non-SNP VMs, so it's safe to always
111 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]) |
112 ms_hyperv.shared_gpa_boundary;
113 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]) |
114 ms_hyperv.shared_gpa_boundary;
116 msg->target_vcpu = hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU);
119 * Add to list before we send the request since we may
120 * receive the response before returning from this routine
122 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
123 list_add_tail(&msginfo->msglistentry,
124 &vmbus_connection.chn_msg_list);
126 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
128 ret = vmbus_post_msg(msg,
129 sizeof(struct vmbus_channel_initiate_contact),
132 trace_vmbus_negotiate_version(msg, ret);
135 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
136 list_del(&msginfo->msglistentry);
137 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
142 /* Wait for the connection response */
143 wait_for_completion(&msginfo->waitevent);
145 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
146 list_del(&msginfo->msglistentry);
147 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
149 /* Check if successful */
150 if (msginfo->response.version_response.version_supported) {
151 vmbus_connection.conn_state = CONNECTED;
153 if (version >= VERSION_WIN10_V5)
154 vmbus_connection.msg_conn_id =
155 msginfo->response.version_response.msg_conn_id;
157 return -ECONNREFUSED;
164 * vmbus_connect - Sends a connect request on the partition service connection
166 int vmbus_connect(void)
168 struct vmbus_channel_msginfo *msginfo = NULL;
172 /* Initialize the vmbus connection */
173 vmbus_connection.conn_state = CONNECTING;
174 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
175 if (!vmbus_connection.work_queue) {
180 vmbus_connection.rescind_work_queue =
181 create_workqueue("hv_vmbus_rescind");
182 if (!vmbus_connection.rescind_work_queue) {
186 vmbus_connection.ignore_any_offer_msg = false;
188 vmbus_connection.handle_primary_chan_wq =
189 create_workqueue("hv_pri_chan");
190 if (!vmbus_connection.handle_primary_chan_wq) {
195 vmbus_connection.handle_sub_chan_wq =
196 create_workqueue("hv_sub_chan");
197 if (!vmbus_connection.handle_sub_chan_wq) {
202 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
203 spin_lock_init(&vmbus_connection.channelmsg_lock);
205 INIT_LIST_HEAD(&vmbus_connection.chn_list);
206 mutex_init(&vmbus_connection.channel_mutex);
209 * Setup the vmbus event connection for channel interrupt
212 vmbus_connection.int_page = hv_alloc_hyperv_zeroed_page();
213 if (vmbus_connection.int_page == NULL) {
218 vmbus_connection.recv_int_page = vmbus_connection.int_page;
219 vmbus_connection.send_int_page =
220 (void *)((unsigned long)vmbus_connection.int_page +
221 (HV_HYP_PAGE_SIZE >> 1));
224 * Setup the monitor notification facility. The 1st page for
225 * parent->child and the 2nd page for child->parent
227 vmbus_connection.monitor_pages[0] = hv_alloc_hyperv_page();
228 vmbus_connection.monitor_pages[1] = hv_alloc_hyperv_page();
229 if ((vmbus_connection.monitor_pages[0] == NULL) ||
230 (vmbus_connection.monitor_pages[1] == NULL)) {
235 ret = set_memory_decrypted((unsigned long)
236 vmbus_connection.monitor_pages[0], 1);
237 ret |= set_memory_decrypted((unsigned long)
238 vmbus_connection.monitor_pages[1], 1);
243 * Set_memory_decrypted() will change the memory contents if
244 * decryption occurs, so zero monitor pages here.
246 memset(vmbus_connection.monitor_pages[0], 0x00, HV_HYP_PAGE_SIZE);
247 memset(vmbus_connection.monitor_pages[1], 0x00, HV_HYP_PAGE_SIZE);
249 msginfo = kzalloc(sizeof(*msginfo) +
250 sizeof(struct vmbus_channel_initiate_contact),
252 if (msginfo == NULL) {
258 * Negotiate a compatible VMBUS version number with the
259 * host. We start with the highest number we can support
260 * and work our way down until we negotiate a compatible
265 if (i == ARRAY_SIZE(vmbus_versions)) {
270 version = vmbus_versions[i];
271 if (version > max_version)
274 ret = vmbus_negotiate_version(msginfo, version);
275 if (ret == -ETIMEDOUT)
278 if (vmbus_connection.conn_state == CONNECTED)
282 if (hv_is_isolation_supported() && version < VERSION_WIN10_V5_2) {
283 pr_err("Invalid VMBus version %d.%d (expected >= %d.%d) from the host supporting isolation\n",
284 version >> 16, version & 0xFFFF, VERSION_WIN10_V5_2 >> 16, VERSION_WIN10_V5_2 & 0xFFFF);
289 vmbus_proto_version = version;
290 pr_info("Vmbus version:%d.%d\n",
291 version >> 16, version & 0xFFFF);
293 vmbus_connection.channels = kcalloc(MAX_CHANNEL_RELIDS,
294 sizeof(struct vmbus_channel *),
296 if (vmbus_connection.channels == NULL) {
305 pr_err("Unable to connect to host\n");
307 vmbus_connection.conn_state = DISCONNECTED;
315 void vmbus_disconnect(void)
318 * First send the unload request to the host.
320 vmbus_initiate_unload(false);
322 if (vmbus_connection.handle_sub_chan_wq)
323 destroy_workqueue(vmbus_connection.handle_sub_chan_wq);
325 if (vmbus_connection.handle_primary_chan_wq)
326 destroy_workqueue(vmbus_connection.handle_primary_chan_wq);
328 if (vmbus_connection.rescind_work_queue)
329 destroy_workqueue(vmbus_connection.rescind_work_queue);
331 if (vmbus_connection.work_queue)
332 destroy_workqueue(vmbus_connection.work_queue);
334 if (vmbus_connection.int_page) {
335 hv_free_hyperv_page(vmbus_connection.int_page);
336 vmbus_connection.int_page = NULL;
339 set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[0], 1);
340 set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[1], 1);
342 hv_free_hyperv_page(vmbus_connection.monitor_pages[0]);
343 hv_free_hyperv_page(vmbus_connection.monitor_pages[1]);
344 vmbus_connection.monitor_pages[0] = NULL;
345 vmbus_connection.monitor_pages[1] = NULL;
349 * relid2channel - Get the channel object given its
350 * child relative id (ie channel id)
352 struct vmbus_channel *relid2channel(u32 relid)
354 if (vmbus_connection.channels == NULL) {
355 pr_warn_once("relid2channel: relid=%d: No channels mapped!\n", relid);
358 if (WARN_ON(relid >= MAX_CHANNEL_RELIDS))
360 return READ_ONCE(vmbus_connection.channels[relid]);
364 * vmbus_on_event - Process a channel event notification
366 * For batched channels (default) optimize host to guest signaling
368 * 1. While reading the channel, we disable interrupts from host.
369 * 2. Ensure that we process all posted messages from the host
370 * before returning from this callback.
371 * 3. Once we return, enable signaling from the host. Once this
372 * state is set we check to see if additional packets are
373 * available to read. In this case we repeat the process.
374 * If this tasklet has been running for a long time
375 * then reschedule ourselves.
377 void vmbus_on_event(unsigned long data)
379 struct vmbus_channel *channel = (void *) data;
380 void (*callback_fn)(void *context);
382 trace_vmbus_on_event(channel);
384 hv_debug_delay_test(channel, INTERRUPT_DELAY);
386 /* A channel once created is persistent even when
387 * there is no driver handling the device. An
388 * unloading driver sets the onchannel_callback to NULL.
390 callback_fn = READ_ONCE(channel->onchannel_callback);
391 if (unlikely(!callback_fn))
394 (*callback_fn)(channel->channel_callback_context);
396 if (channel->callback_mode != HV_CALL_BATCHED)
399 if (likely(hv_end_read(&channel->inbound) == 0))
402 hv_begin_read(&channel->inbound);
403 tasklet_schedule(&channel->callback_event);
407 * vmbus_post_msg - Send a msg on the vmbus's message connection
409 int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
411 struct vmbus_channel_message_header *hdr;
412 union hv_connection_id conn_id;
418 conn_id.u.id = vmbus_connection.msg_conn_id;
421 * hv_post_message() can have transient failures because of
422 * insufficient resources. Retry the operation a couple of
423 * times before giving up.
425 while (retries < 100) {
426 ret = hv_post_message(conn_id, 1, buffer, buflen);
429 case HV_STATUS_INVALID_CONNECTION_ID:
431 * See vmbus_negotiate_version(): VMBus protocol 5.0
432 * and higher require that we must use
433 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
434 * Contact message, but on old hosts that only
435 * support VMBus protocol 4.0 or lower, here we get
436 * HV_STATUS_INVALID_CONNECTION_ID and we should
437 * return an error immediately without retrying.
440 if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT)
443 * We could get this if we send messages too
448 case HV_STATUS_INSUFFICIENT_MEMORY:
449 case HV_STATUS_INSUFFICIENT_BUFFERS:
452 case HV_STATUS_SUCCESS:
455 pr_err("hv_post_msg() failed; error code:%d\n", ret);
460 if (can_sleep && usec > 1000)
462 else if (usec < MAX_UDELAY_MS * 1000)
474 * vmbus_set_event - Send an event notification to the parent
476 void vmbus_set_event(struct vmbus_channel *channel)
478 u32 child_relid = channel->offermsg.child_relid;
480 if (!channel->is_dedicated_interrupt)
481 vmbus_send_interrupt(child_relid);
483 ++channel->sig_events;
485 if (hv_isolation_type_snp())
486 hv_ghcb_hypercall(HVCALL_SIGNAL_EVENT, &channel->sig_event,
487 NULL, sizeof(channel->sig_event));
489 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
491 EXPORT_SYMBOL_GPL(vmbus_set_event);