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1// SPDX-License-Identifier: GPL-2.0-only2/*3 *4 * Copyright (c) 2009, Microsoft Corporation.5 *6 * Authors:7 * Haiyang Zhang <haiyangz@microsoft.com>8 * Hank Janssen <hjanssen@microsoft.com>9 */10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt11 12#include <linux/kernel.h>13#include <linux/sched.h>14#include <linux/wait.h>15#include <linux/delay.h>16#include <linux/mm.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 <linux/io.h>23#include <linux/set_memory.h>24#include <asm/mshyperv.h>25 26#include "hyperv_vmbus.h"27 28 29struct 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),34 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),39};40EXPORT_SYMBOL_GPL(vmbus_connection);41 42/*43 * Negotiated protocol version with the host.44 */45__u32 vmbus_proto_version;46EXPORT_SYMBOL_GPL(vmbus_proto_version);47 48/*49 * Table of VMBus versions listed from newest to oldest.50 * VERSION_WIN7 and VERSION_WS2008 are no longer supported in51 * Linux guests and are not listed.52 */53static __u32 vmbus_versions[] = {54 VERSION_WIN10_V5_3,55 VERSION_WIN10_V5_2,56 VERSION_WIN10_V5_1,57 VERSION_WIN10_V5,58 VERSION_WIN10_V4_1,59 VERSION_WIN10,60 VERSION_WIN8_1,61 VERSION_WIN862};63 64/*65 * Maximal VMBus protocol version guests can negotiate. Useful to cap the66 * VMBus version for testing and debugging purpose.67 */68static uint max_version = VERSION_WIN10_V5_3;69 70module_param(max_version, uint, S_IRUGO);71MODULE_PARM_DESC(max_version,72 "Maximal VMBus protocol version which can be negotiated");73 74int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)75{76 int ret = 0;77 struct vmbus_channel_initiate_contact *msg;78 unsigned long flags;79 80 init_completion(&msginfo->waitevent);81 82 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;83 84 memset(msg, 0, sizeof(*msg));85 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;86 msg->vmbus_version_requested = version;87 88 /*89 * VMBus protocol 5.0 (VERSION_WIN10_V5) and higher require that we must90 * use VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,91 * and for subsequent messages, we must use the Message Connection ID92 * field in the host-returned Version Response Message. And, with93 * VERSION_WIN10_V5 and higher, we don't use msg->interrupt_page, but we94 * tell the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for95 * compatibility.96 *97 * On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1).98 */99 if (version >= VERSION_WIN10_V5) {100 msg->msg_sint = VMBUS_MESSAGE_SINT;101 msg->msg_vtl = ms_hyperv.vtl;102 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;103 } else {104 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);105 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID;106 }107 108 /*109 * shared_gpa_boundary is zero in non-SNP VMs, so it's safe to always110 * bitwise OR it111 */112 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]) |113 ms_hyperv.shared_gpa_boundary;114 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]) |115 ms_hyperv.shared_gpa_boundary;116 117 msg->target_vcpu = hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU);118 119 /*120 * Add to list before we send the request since we may121 * receive the response before returning from this routine122 */123 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);124 list_add_tail(&msginfo->msglistentry,125 &vmbus_connection.chn_msg_list);126 127 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);128 129 ret = vmbus_post_msg(msg,130 sizeof(struct vmbus_channel_initiate_contact),131 true);132 133 trace_vmbus_negotiate_version(msg, ret);134 135 if (ret != 0) {136 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);137 list_del(&msginfo->msglistentry);138 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,139 flags);140 return ret;141 }142 143 /* Wait for the connection response */144 wait_for_completion(&msginfo->waitevent);145 146 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);147 list_del(&msginfo->msglistentry);148 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);149 150 /* Check if successful */151 if (msginfo->response.version_response.version_supported) {152 vmbus_connection.conn_state = CONNECTED;153 154 if (version >= VERSION_WIN10_V5)155 vmbus_connection.msg_conn_id =156 msginfo->response.version_response.msg_conn_id;157 } else {158 return -ECONNREFUSED;159 }160 161 return ret;162}163 164/*165 * vmbus_connect - Sends a connect request on the partition service connection166 */167int vmbus_connect(void)168{169 struct vmbus_channel_msginfo *msginfo = NULL;170 int i, ret = 0;171 __u32 version;172 173 /* Initialize the vmbus connection */174 vmbus_connection.conn_state = CONNECTING;175 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");176 if (!vmbus_connection.work_queue) {177 ret = -ENOMEM;178 goto cleanup;179 }180 181 vmbus_connection.rescind_work_queue =182 create_workqueue("hv_vmbus_rescind");183 if (!vmbus_connection.rescind_work_queue) {184 ret = -ENOMEM;185 goto cleanup;186 }187 vmbus_connection.ignore_any_offer_msg = false;188 189 vmbus_connection.handle_primary_chan_wq =190 create_workqueue("hv_pri_chan");191 if (!vmbus_connection.handle_primary_chan_wq) {192 ret = -ENOMEM;193 goto cleanup;194 }195 196 vmbus_connection.handle_sub_chan_wq =197 create_workqueue("hv_sub_chan");198 if (!vmbus_connection.handle_sub_chan_wq) {199 ret = -ENOMEM;200 goto cleanup;201 }202 203 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);204 spin_lock_init(&vmbus_connection.channelmsg_lock);205 206 INIT_LIST_HEAD(&vmbus_connection.chn_list);207 mutex_init(&vmbus_connection.channel_mutex);208 209 /*210 * Setup the vmbus event connection for channel interrupt211 * abstraction stuff212 */213 vmbus_connection.int_page = hv_alloc_hyperv_zeroed_page();214 if (vmbus_connection.int_page == NULL) {215 ret = -ENOMEM;216 goto cleanup;217 }218 219 vmbus_connection.recv_int_page = vmbus_connection.int_page;220 vmbus_connection.send_int_page =221 (void *)((unsigned long)vmbus_connection.int_page +222 (HV_HYP_PAGE_SIZE >> 1));223 224 /*225 * Setup the monitor notification facility. The 1st page for226 * parent->child and the 2nd page for child->parent227 */228 vmbus_connection.monitor_pages[0] = hv_alloc_hyperv_page();229 vmbus_connection.monitor_pages[1] = hv_alloc_hyperv_page();230 if ((vmbus_connection.monitor_pages[0] == NULL) ||231 (vmbus_connection.monitor_pages[1] == NULL)) {232 ret = -ENOMEM;233 goto cleanup;234 }235 236 ret = set_memory_decrypted((unsigned long)237 vmbus_connection.monitor_pages[0], 1);238 ret |= set_memory_decrypted((unsigned long)239 vmbus_connection.monitor_pages[1], 1);240 if (ret) {241 /*242 * If set_memory_decrypted() fails, the encryption state243 * of the memory is unknown. So leak the memory instead244 * of risking returning decrypted memory to the free list.245 * For simplicity, always handle both pages the same.246 */247 vmbus_connection.monitor_pages[0] = NULL;248 vmbus_connection.monitor_pages[1] = NULL;249 goto cleanup;250 }251 252 /*253 * Set_memory_decrypted() will change the memory contents if254 * decryption occurs, so zero monitor pages here.255 */256 memset(vmbus_connection.monitor_pages[0], 0x00, HV_HYP_PAGE_SIZE);257 memset(vmbus_connection.monitor_pages[1], 0x00, HV_HYP_PAGE_SIZE);258 259 msginfo = kzalloc(sizeof(*msginfo) +260 sizeof(struct vmbus_channel_initiate_contact),261 GFP_KERNEL);262 if (msginfo == NULL) {263 ret = -ENOMEM;264 goto cleanup;265 }266 267 /*268 * Negotiate a compatible VMBUS version number with the269 * host. We start with the highest number we can support270 * and work our way down until we negotiate a compatible271 * version.272 */273 274 for (i = 0; ; i++) {275 if (i == ARRAY_SIZE(vmbus_versions)) {276 ret = -EDOM;277 goto cleanup;278 }279 280 version = vmbus_versions[i];281 if (version > max_version)282 continue;283 284 ret = vmbus_negotiate_version(msginfo, version);285 if (ret == -ETIMEDOUT)286 goto cleanup;287 288 if (vmbus_connection.conn_state == CONNECTED)289 break;290 }291 292 if (hv_is_isolation_supported() && version < VERSION_WIN10_V5_2) {293 pr_err("Invalid VMBus version %d.%d (expected >= %d.%d) from the host supporting isolation\n",294 version >> 16, version & 0xFFFF, VERSION_WIN10_V5_2 >> 16, VERSION_WIN10_V5_2 & 0xFFFF);295 ret = -EINVAL;296 goto cleanup;297 }298 299 vmbus_proto_version = version;300 pr_info("Vmbus version:%d.%d\n",301 version >> 16, version & 0xFFFF);302 303 vmbus_connection.channels = kcalloc(MAX_CHANNEL_RELIDS,304 sizeof(struct vmbus_channel *),305 GFP_KERNEL);306 if (vmbus_connection.channels == NULL) {307 ret = -ENOMEM;308 goto cleanup;309 }310 311 kfree(msginfo);312 return 0;313 314cleanup:315 pr_err("Unable to connect to host\n");316 317 vmbus_connection.conn_state = DISCONNECTED;318 vmbus_disconnect();319 320 kfree(msginfo);321 322 return ret;323}324 325void vmbus_disconnect(void)326{327 /*328 * First send the unload request to the host.329 */330 vmbus_initiate_unload(false);331 332 if (vmbus_connection.handle_sub_chan_wq)333 destroy_workqueue(vmbus_connection.handle_sub_chan_wq);334 335 if (vmbus_connection.handle_primary_chan_wq)336 destroy_workqueue(vmbus_connection.handle_primary_chan_wq);337 338 if (vmbus_connection.rescind_work_queue)339 destroy_workqueue(vmbus_connection.rescind_work_queue);340 341 if (vmbus_connection.work_queue)342 destroy_workqueue(vmbus_connection.work_queue);343 344 if (vmbus_connection.int_page) {345 hv_free_hyperv_page(vmbus_connection.int_page);346 vmbus_connection.int_page = NULL;347 }348 349 if (vmbus_connection.monitor_pages[0]) {350 if (!set_memory_encrypted(351 (unsigned long)vmbus_connection.monitor_pages[0], 1))352 hv_free_hyperv_page(vmbus_connection.monitor_pages[0]);353 vmbus_connection.monitor_pages[0] = NULL;354 }355 356 if (vmbus_connection.monitor_pages[1]) {357 if (!set_memory_encrypted(358 (unsigned long)vmbus_connection.monitor_pages[1], 1))359 hv_free_hyperv_page(vmbus_connection.monitor_pages[1]);360 vmbus_connection.monitor_pages[1] = NULL;361 }362}363 364/*365 * relid2channel - Get the channel object given its366 * child relative id (ie channel id)367 */368struct vmbus_channel *relid2channel(u32 relid)369{370 if (vmbus_connection.channels == NULL) {371 pr_warn_once("relid2channel: relid=%d: No channels mapped!\n", relid);372 return NULL;373 }374 if (WARN_ON(relid >= MAX_CHANNEL_RELIDS))375 return NULL;376 return READ_ONCE(vmbus_connection.channels[relid]);377}378 379/*380 * vmbus_on_event - Process a channel event notification381 *382 * For batched channels (default) optimize host to guest signaling383 * by ensuring:384 * 1. While reading the channel, we disable interrupts from host.385 * 2. Ensure that we process all posted messages from the host386 * before returning from this callback.387 * 3. Once we return, enable signaling from the host. Once this388 * state is set we check to see if additional packets are389 * available to read. In this case we repeat the process.390 * If this tasklet has been running for a long time391 * then reschedule ourselves.392 */393void vmbus_on_event(unsigned long data)394{395 struct vmbus_channel *channel = (void *) data;396 void (*callback_fn)(void *context);397 398 trace_vmbus_on_event(channel);399 400 hv_debug_delay_test(channel, INTERRUPT_DELAY);401 402 /* A channel once created is persistent even when403 * there is no driver handling the device. An404 * unloading driver sets the onchannel_callback to NULL.405 */406 callback_fn = READ_ONCE(channel->onchannel_callback);407 if (unlikely(!callback_fn))408 return;409 410 (*callback_fn)(channel->channel_callback_context);411 412 if (channel->callback_mode != HV_CALL_BATCHED)413 return;414 415 if (likely(hv_end_read(&channel->inbound) == 0))416 return;417 418 hv_begin_read(&channel->inbound);419 tasklet_schedule(&channel->callback_event);420}421 422/*423 * vmbus_post_msg - Send a msg on the vmbus's message connection424 */425int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)426{427 struct vmbus_channel_message_header *hdr;428 union hv_connection_id conn_id;429 int ret = 0;430 int retries = 0;431 u32 usec = 1;432 433 conn_id.asu32 = 0;434 conn_id.u.id = vmbus_connection.msg_conn_id;435 436 /*437 * hv_post_message() can have transient failures because of438 * insufficient resources. Retry the operation a couple of439 * times before giving up.440 */441 while (retries < 100) {442 ret = hv_post_message(conn_id, 1, buffer, buflen);443 444 switch (ret) {445 case HV_STATUS_INVALID_CONNECTION_ID:446 /*447 * See vmbus_negotiate_version(): VMBus protocol 5.0448 * and higher require that we must use449 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate450 * Contact message, but on old hosts that only451 * support VMBus protocol 4.0 or lower, here we get452 * HV_STATUS_INVALID_CONNECTION_ID and we should453 * return an error immediately without retrying.454 */455 hdr = buffer;456 if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT)457 return -EINVAL;458 /*459 * We could get this if we send messages too460 * frequently.461 */462 ret = -EAGAIN;463 break;464 case HV_STATUS_INSUFFICIENT_MEMORY:465 case HV_STATUS_INSUFFICIENT_BUFFERS:466 ret = -ENOBUFS;467 break;468 case HV_STATUS_SUCCESS:469 return ret;470 default:471 pr_err("hv_post_msg() failed; error code:%d\n", ret);472 return -EINVAL;473 }474 475 retries++;476 if (can_sleep && usec > 1000)477 msleep(usec / 1000);478 else if (usec < MAX_UDELAY_MS * 1000)479 udelay(usec);480 else481 mdelay(usec / 1000);482 483 if (retries < 22)484 usec *= 2;485 }486 return ret;487}488 489/*490 * vmbus_set_event - Send an event notification to the parent491 */492void vmbus_set_event(struct vmbus_channel *channel)493{494 u32 child_relid = channel->offermsg.child_relid;495 496 if (!channel->is_dedicated_interrupt)497 vmbus_send_interrupt(child_relid);498 499 ++channel->sig_events;500 501 if (ms_hyperv.paravisor_present) {502 if (hv_isolation_type_snp())503 hv_ghcb_hypercall(HVCALL_SIGNAL_EVENT, &channel->sig_event,504 NULL, sizeof(channel->sig_event));505 else if (hv_isolation_type_tdx())506 hv_tdx_hypercall(HVCALL_SIGNAL_EVENT | HV_HYPERCALL_FAST_BIT,507 channel->sig_event, 0);508 else509 WARN_ON_ONCE(1);510 } else {511 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);512 }513}514EXPORT_SYMBOL_GPL(vmbus_set_event);515