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Note: File does not exist in v3.5.6.
   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Virtio vhost-user driver
   4 *
   5 * Copyright(c) 2019 Intel Corporation
   6 *
   7 * This driver allows virtio devices to be used over a vhost-user socket.
   8 *
   9 * Guest devices can be instantiated by kernel module or command line
  10 * parameters. One device will be created for each parameter. Syntax:
  11 *
  12 *		virtio_uml.device=<socket>:<virtio_id>[:<platform_id>]
  13 * where:
  14 *		<socket>	:= vhost-user socket path to connect
  15 *		<virtio_id>	:= virtio device id (as in virtio_ids.h)
  16 *		<platform_id>	:= (optional) platform device id
  17 *
  18 * example:
  19 *		virtio_uml.device=/var/uml.socket:1
  20 *
  21 * Based on Virtio MMIO driver by Pawel Moll, copyright 2011-2014, ARM Ltd.
  22 */
  23#include <linux/module.h>
  24#include <linux/of.h>
  25#include <linux/platform_device.h>
  26#include <linux/slab.h>
  27#include <linux/virtio.h>
  28#include <linux/virtio_config.h>
  29#include <linux/virtio_ring.h>
  30#include <linux/time-internal.h>
  31#include <linux/virtio-uml.h>
  32#include <shared/as-layout.h>
  33#include <irq_kern.h>
  34#include <init.h>
  35#include <os.h>
  36#include "vhost_user.h"
  37
  38#define MAX_SUPPORTED_QUEUE_SIZE	256
  39
  40#define to_virtio_uml_device(_vdev) \
  41	container_of(_vdev, struct virtio_uml_device, vdev)
  42
  43struct virtio_uml_platform_data {
  44	u32 virtio_device_id;
  45	const char *socket_path;
  46	struct work_struct conn_broken_wk;
  47	struct platform_device *pdev;
  48};
  49
  50struct virtio_uml_device {
  51	struct virtio_device vdev;
  52	struct platform_device *pdev;
  53	struct virtio_uml_platform_data *pdata;
  54
  55	spinlock_t sock_lock;
  56	int sock, req_fd, irq;
  57	u64 features;
  58	u64 protocol_features;
  59	u64 max_vqs;
  60	u8 status;
  61	u8 registered:1;
  62	u8 suspended:1;
  63	u8 no_vq_suspend:1;
  64
  65	u8 config_changed_irq:1;
  66	uint64_t vq_irq_vq_map;
  67	int recv_rc;
  68};
  69
  70struct virtio_uml_vq_info {
  71	int kick_fd, call_fd;
  72	char name[32];
  73	bool suspended;
  74};
  75
  76#define vu_err(vu_dev, ...)	dev_err(&(vu_dev)->pdev->dev, ##__VA_ARGS__)
  77
  78/* Vhost-user protocol */
  79
  80static int full_sendmsg_fds(int fd, const void *buf, unsigned int len,
  81			    const int *fds, unsigned int fds_num)
  82{
  83	int rc;
  84
  85	do {
  86		rc = os_sendmsg_fds(fd, buf, len, fds, fds_num);
  87		if (rc > 0) {
  88			buf += rc;
  89			len -= rc;
  90			fds = NULL;
  91			fds_num = 0;
  92		}
  93	} while (len && (rc >= 0 || rc == -EINTR));
  94
  95	if (rc < 0)
  96		return rc;
  97	return 0;
  98}
  99
 100static int full_read(int fd, void *buf, int len, bool abortable)
 101{
 102	int rc;
 103
 104	if (!len)
 105		return 0;
 106
 107	do {
 108		rc = os_read_file(fd, buf, len);
 109		if (rc > 0) {
 110			buf += rc;
 111			len -= rc;
 112		}
 113	} while (len && (rc > 0 || rc == -EINTR || (!abortable && rc == -EAGAIN)));
 114
 115	if (rc < 0)
 116		return rc;
 117	if (rc == 0)
 118		return -ECONNRESET;
 119	return 0;
 120}
 121
 122static int vhost_user_recv_header(int fd, struct vhost_user_msg *msg)
 123{
 124	return full_read(fd, msg, sizeof(msg->header), true);
 125}
 126
 127static int vhost_user_recv(struct virtio_uml_device *vu_dev,
 128			   int fd, struct vhost_user_msg *msg,
 129			   size_t max_payload_size, bool wait)
 130{
 131	size_t size;
 132	int rc;
 133
 134	/*
 135	 * In virtio time-travel mode, we're handling all the vhost-user
 136	 * FDs by polling them whenever appropriate. However, we may get
 137	 * into a situation where we're sending out an interrupt message
 138	 * to a device (e.g. a net device) and need to handle a simulation
 139	 * time message while doing so, e.g. one that tells us to update
 140	 * our idea of how long we can run without scheduling.
 141	 *
 142	 * Thus, we need to not just read() from the given fd, but need
 143	 * to also handle messages for the simulation time - this function
 144	 * does that for us while waiting for the given fd to be readable.
 145	 */
 146	if (wait)
 147		time_travel_wait_readable(fd);
 148
 149	rc = vhost_user_recv_header(fd, msg);
 150
 151	if (rc)
 152		return rc;
 153	size = msg->header.size;
 154	if (size > max_payload_size)
 155		return -EPROTO;
 156	return full_read(fd, &msg->payload, size, false);
 157}
 158
 159static void vhost_user_check_reset(struct virtio_uml_device *vu_dev,
 160				   int rc)
 161{
 162	struct virtio_uml_platform_data *pdata = vu_dev->pdata;
 163
 164	if (rc != -ECONNRESET)
 165		return;
 166
 167	if (!vu_dev->registered)
 168		return;
 169
 170	vu_dev->registered = 0;
 171
 172	schedule_work(&pdata->conn_broken_wk);
 173}
 174
 175static int vhost_user_recv_resp(struct virtio_uml_device *vu_dev,
 176				struct vhost_user_msg *msg,
 177				size_t max_payload_size)
 178{
 179	int rc = vhost_user_recv(vu_dev, vu_dev->sock, msg,
 180				 max_payload_size, true);
 181
 182	if (rc) {
 183		vhost_user_check_reset(vu_dev, rc);
 184		return rc;
 185	}
 186
 187	if (msg->header.flags != (VHOST_USER_FLAG_REPLY | VHOST_USER_VERSION))
 188		return -EPROTO;
 189
 190	return 0;
 191}
 192
 193static int vhost_user_recv_u64(struct virtio_uml_device *vu_dev,
 194			       u64 *value)
 195{
 196	struct vhost_user_msg msg;
 197	int rc = vhost_user_recv_resp(vu_dev, &msg,
 198				      sizeof(msg.payload.integer));
 199
 200	if (rc)
 201		return rc;
 202	if (msg.header.size != sizeof(msg.payload.integer))
 203		return -EPROTO;
 204	*value = msg.payload.integer;
 205	return 0;
 206}
 207
 208static int vhost_user_recv_req(struct virtio_uml_device *vu_dev,
 209			       struct vhost_user_msg *msg,
 210			       size_t max_payload_size)
 211{
 212	int rc = vhost_user_recv(vu_dev, vu_dev->req_fd, msg,
 213				 max_payload_size, false);
 214
 215	if (rc)
 216		return rc;
 217
 218	if ((msg->header.flags & ~VHOST_USER_FLAG_NEED_REPLY) !=
 219			VHOST_USER_VERSION)
 220		return -EPROTO;
 221
 222	return 0;
 223}
 224
 225static int vhost_user_send(struct virtio_uml_device *vu_dev,
 226			   bool need_response, struct vhost_user_msg *msg,
 227			   int *fds, size_t num_fds)
 228{
 229	size_t size = sizeof(msg->header) + msg->header.size;
 230	unsigned long flags;
 231	bool request_ack;
 232	int rc;
 233
 234	msg->header.flags |= VHOST_USER_VERSION;
 235
 236	/*
 237	 * The need_response flag indicates that we already need a response,
 238	 * e.g. to read the features. In these cases, don't request an ACK as
 239	 * it is meaningless. Also request an ACK only if supported.
 240	 */
 241	request_ack = !need_response;
 242	if (!(vu_dev->protocol_features &
 243			BIT_ULL(VHOST_USER_PROTOCOL_F_REPLY_ACK)))
 244		request_ack = false;
 245
 246	if (request_ack)
 247		msg->header.flags |= VHOST_USER_FLAG_NEED_REPLY;
 248
 249	spin_lock_irqsave(&vu_dev->sock_lock, flags);
 250	rc = full_sendmsg_fds(vu_dev->sock, msg, size, fds, num_fds);
 251	if (rc < 0)
 252		goto out;
 253
 254	if (request_ack) {
 255		uint64_t status;
 256
 257		rc = vhost_user_recv_u64(vu_dev, &status);
 258		if (rc)
 259			goto out;
 260
 261		if (status) {
 262			vu_err(vu_dev, "slave reports error: %llu\n", status);
 263			rc = -EIO;
 264			goto out;
 265		}
 266	}
 267
 268out:
 269	spin_unlock_irqrestore(&vu_dev->sock_lock, flags);
 270	return rc;
 271}
 272
 273static int vhost_user_send_no_payload(struct virtio_uml_device *vu_dev,
 274				      bool need_response, u32 request)
 275{
 276	struct vhost_user_msg msg = {
 277		.header.request = request,
 278	};
 279
 280	return vhost_user_send(vu_dev, need_response, &msg, NULL, 0);
 281}
 282
 283static int vhost_user_send_no_payload_fd(struct virtio_uml_device *vu_dev,
 284					 u32 request, int fd)
 285{
 286	struct vhost_user_msg msg = {
 287		.header.request = request,
 288	};
 289
 290	return vhost_user_send(vu_dev, false, &msg, &fd, 1);
 291}
 292
 293static int vhost_user_send_u64(struct virtio_uml_device *vu_dev,
 294			       u32 request, u64 value)
 295{
 296	struct vhost_user_msg msg = {
 297		.header.request = request,
 298		.header.size = sizeof(msg.payload.integer),
 299		.payload.integer = value,
 300	};
 301
 302	return vhost_user_send(vu_dev, false, &msg, NULL, 0);
 303}
 304
 305static int vhost_user_set_owner(struct virtio_uml_device *vu_dev)
 306{
 307	return vhost_user_send_no_payload(vu_dev, false, VHOST_USER_SET_OWNER);
 308}
 309
 310static int vhost_user_get_features(struct virtio_uml_device *vu_dev,
 311				   u64 *features)
 312{
 313	int rc = vhost_user_send_no_payload(vu_dev, true,
 314					    VHOST_USER_GET_FEATURES);
 315
 316	if (rc)
 317		return rc;
 318	return vhost_user_recv_u64(vu_dev, features);
 319}
 320
 321static int vhost_user_set_features(struct virtio_uml_device *vu_dev,
 322				   u64 features)
 323{
 324	return vhost_user_send_u64(vu_dev, VHOST_USER_SET_FEATURES, features);
 325}
 326
 327static int vhost_user_get_protocol_features(struct virtio_uml_device *vu_dev,
 328					    u64 *protocol_features)
 329{
 330	int rc = vhost_user_send_no_payload(vu_dev, true,
 331			VHOST_USER_GET_PROTOCOL_FEATURES);
 332
 333	if (rc)
 334		return rc;
 335	return vhost_user_recv_u64(vu_dev, protocol_features);
 336}
 337
 338static int vhost_user_set_protocol_features(struct virtio_uml_device *vu_dev,
 339					    u64 protocol_features)
 340{
 341	return vhost_user_send_u64(vu_dev, VHOST_USER_SET_PROTOCOL_FEATURES,
 342				   protocol_features);
 343}
 344
 345static int vhost_user_get_queue_num(struct virtio_uml_device *vu_dev,
 346				    u64 *queue_num)
 347{
 348	int rc = vhost_user_send_no_payload(vu_dev, true,
 349			VHOST_USER_GET_QUEUE_NUM);
 350
 351	if (rc)
 352		return rc;
 353	return vhost_user_recv_u64(vu_dev, queue_num);
 354}
 355
 356static void vhost_user_reply(struct virtio_uml_device *vu_dev,
 357			     struct vhost_user_msg *msg, int response)
 358{
 359	struct vhost_user_msg reply = {
 360		.payload.integer = response,
 361	};
 362	size_t size = sizeof(reply.header) + sizeof(reply.payload.integer);
 363	int rc;
 364
 365	reply.header = msg->header;
 366	reply.header.flags &= ~VHOST_USER_FLAG_NEED_REPLY;
 367	reply.header.flags |= VHOST_USER_FLAG_REPLY;
 368	reply.header.size = sizeof(reply.payload.integer);
 369
 370	rc = full_sendmsg_fds(vu_dev->req_fd, &reply, size, NULL, 0);
 371
 372	if (rc)
 373		vu_err(vu_dev,
 374		       "sending reply to slave request failed: %d (size %zu)\n",
 375		       rc, size);
 376}
 377
 378static irqreturn_t vu_req_read_message(struct virtio_uml_device *vu_dev,
 379				       struct time_travel_event *ev)
 380{
 381	struct virtqueue *vq;
 382	int response = 1;
 383	struct {
 384		struct vhost_user_msg msg;
 385		u8 extra_payload[512];
 386	} msg;
 387	int rc;
 388	irqreturn_t irq_rc = IRQ_NONE;
 389
 390	while (1) {
 391		rc = vhost_user_recv_req(vu_dev, &msg.msg,
 392					 sizeof(msg.msg.payload) +
 393					 sizeof(msg.extra_payload));
 394		if (rc)
 395			break;
 396
 397		switch (msg.msg.header.request) {
 398		case VHOST_USER_SLAVE_CONFIG_CHANGE_MSG:
 399			vu_dev->config_changed_irq = true;
 400			response = 0;
 401			break;
 402		case VHOST_USER_SLAVE_VRING_CALL:
 403			virtio_device_for_each_vq((&vu_dev->vdev), vq) {
 404				if (vq->index == msg.msg.payload.vring_state.index) {
 405					response = 0;
 406					vu_dev->vq_irq_vq_map |= BIT_ULL(vq->index);
 407					break;
 408				}
 409			}
 410			break;
 411		case VHOST_USER_SLAVE_IOTLB_MSG:
 412			/* not supported - VIRTIO_F_ACCESS_PLATFORM */
 413		case VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG:
 414			/* not supported - VHOST_USER_PROTOCOL_F_HOST_NOTIFIER */
 415		default:
 416			vu_err(vu_dev, "unexpected slave request %d\n",
 417			       msg.msg.header.request);
 418		}
 419
 420		if (ev && !vu_dev->suspended)
 421			time_travel_add_irq_event(ev);
 422
 423		if (msg.msg.header.flags & VHOST_USER_FLAG_NEED_REPLY)
 424			vhost_user_reply(vu_dev, &msg.msg, response);
 425		irq_rc = IRQ_HANDLED;
 426	}
 427	/* mask EAGAIN as we try non-blocking read until socket is empty */
 428	vu_dev->recv_rc = (rc == -EAGAIN) ? 0 : rc;
 429	return irq_rc;
 430}
 431
 432static irqreturn_t vu_req_interrupt(int irq, void *data)
 433{
 434	struct virtio_uml_device *vu_dev = data;
 435	irqreturn_t ret = IRQ_HANDLED;
 436
 437	if (!um_irq_timetravel_handler_used())
 438		ret = vu_req_read_message(vu_dev, NULL);
 439
 440	if (vu_dev->recv_rc) {
 441		vhost_user_check_reset(vu_dev, vu_dev->recv_rc);
 442	} else if (vu_dev->vq_irq_vq_map) {
 443		struct virtqueue *vq;
 444
 445		virtio_device_for_each_vq((&vu_dev->vdev), vq) {
 446			if (vu_dev->vq_irq_vq_map & BIT_ULL(vq->index))
 447				vring_interrupt(0 /* ignored */, vq);
 448		}
 449		vu_dev->vq_irq_vq_map = 0;
 450	} else if (vu_dev->config_changed_irq) {
 451		virtio_config_changed(&vu_dev->vdev);
 452		vu_dev->config_changed_irq = false;
 453	}
 454
 455	return ret;
 456}
 457
 458static void vu_req_interrupt_comm_handler(int irq, int fd, void *data,
 459					  struct time_travel_event *ev)
 460{
 461	vu_req_read_message(data, ev);
 462}
 463
 464static int vhost_user_init_slave_req(struct virtio_uml_device *vu_dev)
 465{
 466	int rc, req_fds[2];
 467
 468	/* Use a pipe for slave req fd, SIGIO is not supported for eventfd */
 469	rc = os_pipe(req_fds, true, true);
 470	if (rc < 0)
 471		return rc;
 472	vu_dev->req_fd = req_fds[0];
 473
 474	rc = um_request_irq_tt(UM_IRQ_ALLOC, vu_dev->req_fd, IRQ_READ,
 475			       vu_req_interrupt, IRQF_SHARED,
 476			       vu_dev->pdev->name, vu_dev,
 477			       vu_req_interrupt_comm_handler);
 478	if (rc < 0)
 479		goto err_close;
 480
 481	vu_dev->irq = rc;
 482
 483	rc = vhost_user_send_no_payload_fd(vu_dev, VHOST_USER_SET_SLAVE_REQ_FD,
 484					   req_fds[1]);
 485	if (rc)
 486		goto err_free_irq;
 487
 488	goto out;
 489
 490err_free_irq:
 491	um_free_irq(vu_dev->irq, vu_dev);
 492err_close:
 493	os_close_file(req_fds[0]);
 494out:
 495	/* Close unused write end of request fds */
 496	os_close_file(req_fds[1]);
 497	return rc;
 498}
 499
 500static int vhost_user_init(struct virtio_uml_device *vu_dev)
 501{
 502	int rc = vhost_user_set_owner(vu_dev);
 503
 504	if (rc)
 505		return rc;
 506	rc = vhost_user_get_features(vu_dev, &vu_dev->features);
 507	if (rc)
 508		return rc;
 509
 510	if (vu_dev->features & BIT_ULL(VHOST_USER_F_PROTOCOL_FEATURES)) {
 511		rc = vhost_user_get_protocol_features(vu_dev,
 512				&vu_dev->protocol_features);
 513		if (rc)
 514			return rc;
 515		vu_dev->protocol_features &= VHOST_USER_SUPPORTED_PROTOCOL_F;
 516		rc = vhost_user_set_protocol_features(vu_dev,
 517				vu_dev->protocol_features);
 518		if (rc)
 519			return rc;
 520	}
 521
 522	if (vu_dev->protocol_features &
 523			BIT_ULL(VHOST_USER_PROTOCOL_F_SLAVE_REQ)) {
 524		rc = vhost_user_init_slave_req(vu_dev);
 525		if (rc)
 526			return rc;
 527	}
 528
 529	if (vu_dev->protocol_features &
 530			BIT_ULL(VHOST_USER_PROTOCOL_F_MQ)) {
 531		rc = vhost_user_get_queue_num(vu_dev, &vu_dev->max_vqs);
 532		if (rc)
 533			return rc;
 534	} else {
 535		vu_dev->max_vqs = U64_MAX;
 536	}
 537
 538	return 0;
 539}
 540
 541static void vhost_user_get_config(struct virtio_uml_device *vu_dev,
 542				  u32 offset, void *buf, u32 len)
 543{
 544	u32 cfg_size = offset + len;
 545	struct vhost_user_msg *msg;
 546	size_t payload_size = sizeof(msg->payload.config) + cfg_size;
 547	size_t msg_size = sizeof(msg->header) + payload_size;
 548	int rc;
 549
 550	if (!(vu_dev->protocol_features &
 551	      BIT_ULL(VHOST_USER_PROTOCOL_F_CONFIG)))
 552		return;
 553
 554	msg = kzalloc(msg_size, GFP_KERNEL);
 555	if (!msg)
 556		return;
 557	msg->header.request = VHOST_USER_GET_CONFIG;
 558	msg->header.size = payload_size;
 559	msg->payload.config.offset = 0;
 560	msg->payload.config.size = cfg_size;
 561
 562	rc = vhost_user_send(vu_dev, true, msg, NULL, 0);
 563	if (rc) {
 564		vu_err(vu_dev, "sending VHOST_USER_GET_CONFIG failed: %d\n",
 565		       rc);
 566		goto free;
 567	}
 568
 569	rc = vhost_user_recv_resp(vu_dev, msg, msg_size);
 570	if (rc) {
 571		vu_err(vu_dev,
 572		       "receiving VHOST_USER_GET_CONFIG response failed: %d\n",
 573		       rc);
 574		goto free;
 575	}
 576
 577	if (msg->header.size != payload_size ||
 578	    msg->payload.config.size != cfg_size) {
 579		rc = -EPROTO;
 580		vu_err(vu_dev,
 581		       "Invalid VHOST_USER_GET_CONFIG sizes (payload %d expected %zu, config %u expected %u)\n",
 582		       msg->header.size, payload_size,
 583		       msg->payload.config.size, cfg_size);
 584		goto free;
 585	}
 586	memcpy(buf, msg->payload.config.payload + offset, len);
 587
 588free:
 589	kfree(msg);
 590}
 591
 592static void vhost_user_set_config(struct virtio_uml_device *vu_dev,
 593				  u32 offset, const void *buf, u32 len)
 594{
 595	struct vhost_user_msg *msg;
 596	size_t payload_size = sizeof(msg->payload.config) + len;
 597	size_t msg_size = sizeof(msg->header) + payload_size;
 598	int rc;
 599
 600	if (!(vu_dev->protocol_features &
 601	      BIT_ULL(VHOST_USER_PROTOCOL_F_CONFIG)))
 602		return;
 603
 604	msg = kzalloc(msg_size, GFP_KERNEL);
 605	if (!msg)
 606		return;
 607	msg->header.request = VHOST_USER_SET_CONFIG;
 608	msg->header.size = payload_size;
 609	msg->payload.config.offset = offset;
 610	msg->payload.config.size = len;
 611	memcpy(msg->payload.config.payload, buf, len);
 612
 613	rc = vhost_user_send(vu_dev, false, msg, NULL, 0);
 614	if (rc)
 615		vu_err(vu_dev, "sending VHOST_USER_SET_CONFIG failed: %d\n",
 616		       rc);
 617
 618	kfree(msg);
 619}
 620
 621static int vhost_user_init_mem_region(u64 addr, u64 size, int *fd_out,
 622				      struct vhost_user_mem_region *region_out)
 623{
 624	unsigned long long mem_offset;
 625	int rc = phys_mapping(addr, &mem_offset);
 626
 627	if (WARN(rc < 0, "phys_mapping of 0x%llx returned %d\n", addr, rc))
 628		return -EFAULT;
 629	*fd_out = rc;
 630	region_out->guest_addr = addr;
 631	region_out->user_addr = addr;
 632	region_out->size = size;
 633	region_out->mmap_offset = mem_offset;
 634
 635	/* Ensure mapping is valid for the entire region */
 636	rc = phys_mapping(addr + size - 1, &mem_offset);
 637	if (WARN(rc != *fd_out, "phys_mapping of 0x%llx failed: %d != %d\n",
 638		 addr + size - 1, rc, *fd_out))
 639		return -EFAULT;
 640	return 0;
 641}
 642
 643static int vhost_user_set_mem_table(struct virtio_uml_device *vu_dev)
 644{
 645	struct vhost_user_msg msg = {
 646		.header.request = VHOST_USER_SET_MEM_TABLE,
 647		.header.size = offsetof(typeof(msg.payload.mem_regions), regions[1]),
 648		.payload.mem_regions.num = 1,
 649	};
 650	unsigned long reserved = uml_reserved - uml_physmem;
 651	int fds[2];
 652	int rc;
 653
 654	/*
 655	 * This is a bit tricky, see also the comment with setup_physmem().
 656	 *
 657	 * Essentially, setup_physmem() uses a file to mmap() our physmem,
 658	 * but the code and data we *already* have is omitted. To us, this
 659	 * is no difference, since they both become part of our address
 660	 * space and memory consumption. To somebody looking in from the
 661	 * outside, however, it is different because the part of our memory
 662	 * consumption that's already part of the binary (code/data) is not
 663	 * mapped from the file, so it's not visible to another mmap from
 664	 * the file descriptor.
 665	 *
 666	 * Thus, don't advertise this space to the vhost-user slave. This
 667	 * means that the slave will likely abort or similar when we give
 668	 * it an address from the hidden range, since it's not marked as
 669	 * a valid address, but at least that way we detect the issue and
 670	 * don't just have the slave read an all-zeroes buffer from the
 671	 * shared memory file, or write something there that we can never
 672	 * see (depending on the direction of the virtqueue traffic.)
 673	 *
 674	 * Since we usually don't want to use .text for virtio buffers,
 675	 * this effectively means that you cannot use
 676	 *  1) global variables, which are in the .bss and not in the shm
 677	 *     file-backed memory
 678	 *  2) the stack in some processes, depending on where they have
 679	 *     their stack (or maybe only no interrupt stack?)
 680	 *
 681	 * The stack is already not typically valid for DMA, so this isn't
 682	 * much of a restriction, but global variables might be encountered.
 683	 *
 684	 * It might be possible to fix it by copying around the data that's
 685	 * between bss_start and where we map the file now, but it's not
 686	 * something that you typically encounter with virtio drivers, so
 687	 * it didn't seem worthwhile.
 688	 */
 689	rc = vhost_user_init_mem_region(reserved, physmem_size - reserved,
 690					&fds[0],
 691					&msg.payload.mem_regions.regions[0]);
 692
 693	if (rc < 0)
 694		return rc;
 695
 696	return vhost_user_send(vu_dev, false, &msg, fds,
 697			       msg.payload.mem_regions.num);
 698}
 699
 700static int vhost_user_set_vring_state(struct virtio_uml_device *vu_dev,
 701				      u32 request, u32 index, u32 num)
 702{
 703	struct vhost_user_msg msg = {
 704		.header.request = request,
 705		.header.size = sizeof(msg.payload.vring_state),
 706		.payload.vring_state.index = index,
 707		.payload.vring_state.num = num,
 708	};
 709
 710	return vhost_user_send(vu_dev, false, &msg, NULL, 0);
 711}
 712
 713static int vhost_user_set_vring_num(struct virtio_uml_device *vu_dev,
 714				    u32 index, u32 num)
 715{
 716	return vhost_user_set_vring_state(vu_dev, VHOST_USER_SET_VRING_NUM,
 717					  index, num);
 718}
 719
 720static int vhost_user_set_vring_base(struct virtio_uml_device *vu_dev,
 721				     u32 index, u32 offset)
 722{
 723	return vhost_user_set_vring_state(vu_dev, VHOST_USER_SET_VRING_BASE,
 724					  index, offset);
 725}
 726
 727static int vhost_user_set_vring_addr(struct virtio_uml_device *vu_dev,
 728				     u32 index, u64 desc, u64 used, u64 avail,
 729				     u64 log)
 730{
 731	struct vhost_user_msg msg = {
 732		.header.request = VHOST_USER_SET_VRING_ADDR,
 733		.header.size = sizeof(msg.payload.vring_addr),
 734		.payload.vring_addr.index = index,
 735		.payload.vring_addr.desc = desc,
 736		.payload.vring_addr.used = used,
 737		.payload.vring_addr.avail = avail,
 738		.payload.vring_addr.log = log,
 739	};
 740
 741	return vhost_user_send(vu_dev, false, &msg, NULL, 0);
 742}
 743
 744static int vhost_user_set_vring_fd(struct virtio_uml_device *vu_dev,
 745				   u32 request, int index, int fd)
 746{
 747	struct vhost_user_msg msg = {
 748		.header.request = request,
 749		.header.size = sizeof(msg.payload.integer),
 750		.payload.integer = index,
 751	};
 752
 753	if (index & ~VHOST_USER_VRING_INDEX_MASK)
 754		return -EINVAL;
 755	if (fd < 0) {
 756		msg.payload.integer |= VHOST_USER_VRING_POLL_MASK;
 757		return vhost_user_send(vu_dev, false, &msg, NULL, 0);
 758	}
 759	return vhost_user_send(vu_dev, false, &msg, &fd, 1);
 760}
 761
 762static int vhost_user_set_vring_call(struct virtio_uml_device *vu_dev,
 763				     int index, int fd)
 764{
 765	return vhost_user_set_vring_fd(vu_dev, VHOST_USER_SET_VRING_CALL,
 766				       index, fd);
 767}
 768
 769static int vhost_user_set_vring_kick(struct virtio_uml_device *vu_dev,
 770				     int index, int fd)
 771{
 772	return vhost_user_set_vring_fd(vu_dev, VHOST_USER_SET_VRING_KICK,
 773				       index, fd);
 774}
 775
 776static int vhost_user_set_vring_enable(struct virtio_uml_device *vu_dev,
 777				       u32 index, bool enable)
 778{
 779	if (!(vu_dev->features & BIT_ULL(VHOST_USER_F_PROTOCOL_FEATURES)))
 780		return 0;
 781
 782	return vhost_user_set_vring_state(vu_dev, VHOST_USER_SET_VRING_ENABLE,
 783					  index, enable);
 784}
 785
 786
 787/* Virtio interface */
 788
 789static bool vu_notify(struct virtqueue *vq)
 790{
 791	struct virtio_uml_vq_info *info = vq->priv;
 792	const uint64_t n = 1;
 793	int rc;
 794
 795	if (info->suspended)
 796		return true;
 797
 798	time_travel_propagate_time();
 799
 800	if (info->kick_fd < 0) {
 801		struct virtio_uml_device *vu_dev;
 802
 803		vu_dev = to_virtio_uml_device(vq->vdev);
 804
 805		return vhost_user_set_vring_state(vu_dev, VHOST_USER_VRING_KICK,
 806						  vq->index, 0) == 0;
 807	}
 808
 809	do {
 810		rc = os_write_file(info->kick_fd, &n, sizeof(n));
 811	} while (rc == -EINTR);
 812	return !WARN(rc != sizeof(n), "write returned %d\n", rc);
 813}
 814
 815static irqreturn_t vu_interrupt(int irq, void *opaque)
 816{
 817	struct virtqueue *vq = opaque;
 818	struct virtio_uml_vq_info *info = vq->priv;
 819	uint64_t n;
 820	int rc;
 821	irqreturn_t ret = IRQ_NONE;
 822
 823	do {
 824		rc = os_read_file(info->call_fd, &n, sizeof(n));
 825		if (rc == sizeof(n))
 826			ret |= vring_interrupt(irq, vq);
 827	} while (rc == sizeof(n) || rc == -EINTR);
 828	WARN(rc != -EAGAIN, "read returned %d\n", rc);
 829	return ret;
 830}
 831
 832
 833static void vu_get(struct virtio_device *vdev, unsigned offset,
 834		   void *buf, unsigned len)
 835{
 836	struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
 837
 838	vhost_user_get_config(vu_dev, offset, buf, len);
 839}
 840
 841static void vu_set(struct virtio_device *vdev, unsigned offset,
 842		   const void *buf, unsigned len)
 843{
 844	struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
 845
 846	vhost_user_set_config(vu_dev, offset, buf, len);
 847}
 848
 849static u8 vu_get_status(struct virtio_device *vdev)
 850{
 851	struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
 852
 853	return vu_dev->status;
 854}
 855
 856static void vu_set_status(struct virtio_device *vdev, u8 status)
 857{
 858	struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
 859
 860	vu_dev->status = status;
 861}
 862
 863static void vu_reset(struct virtio_device *vdev)
 864{
 865	struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
 866
 867	vu_dev->status = 0;
 868}
 869
 870static void vu_del_vq(struct virtqueue *vq)
 871{
 872	struct virtio_uml_vq_info *info = vq->priv;
 873
 874	if (info->call_fd >= 0) {
 875		struct virtio_uml_device *vu_dev;
 876
 877		vu_dev = to_virtio_uml_device(vq->vdev);
 878
 879		um_free_irq(vu_dev->irq, vq);
 880		os_close_file(info->call_fd);
 881	}
 882
 883	if (info->kick_fd >= 0)
 884		os_close_file(info->kick_fd);
 885
 886	vring_del_virtqueue(vq);
 887	kfree(info);
 888}
 889
 890static void vu_del_vqs(struct virtio_device *vdev)
 891{
 892	struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
 893	struct virtqueue *vq, *n;
 894	u64 features;
 895
 896	/* Note: reverse order as a workaround to a decoding bug in snabb */
 897	list_for_each_entry_reverse(vq, &vdev->vqs, list)
 898		WARN_ON(vhost_user_set_vring_enable(vu_dev, vq->index, false));
 899
 900	/* Ensure previous messages have been processed */
 901	WARN_ON(vhost_user_get_features(vu_dev, &features));
 902
 903	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
 904		vu_del_vq(vq);
 905}
 906
 907static int vu_setup_vq_call_fd(struct virtio_uml_device *vu_dev,
 908			       struct virtqueue *vq)
 909{
 910	struct virtio_uml_vq_info *info = vq->priv;
 911	int call_fds[2];
 912	int rc, irq;
 913
 914	/* no call FD needed/desired in this case */
 915	if (vu_dev->protocol_features &
 916			BIT_ULL(VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS) &&
 917	    vu_dev->protocol_features &
 918			BIT_ULL(VHOST_USER_PROTOCOL_F_SLAVE_REQ)) {
 919		info->call_fd = -1;
 920		return 0;
 921	}
 922
 923	/* Use a pipe for call fd, since SIGIO is not supported for eventfd */
 924	rc = os_pipe(call_fds, true, true);
 925	if (rc < 0)
 926		return rc;
 927
 928	info->call_fd = call_fds[0];
 929	irq = um_request_irq(vu_dev->irq, info->call_fd, IRQ_READ,
 930			     vu_interrupt, IRQF_SHARED, info->name, vq);
 931	if (irq < 0) {
 932		rc = irq;
 933		goto close_both;
 934	}
 935
 936	rc = vhost_user_set_vring_call(vu_dev, vq->index, call_fds[1]);
 937	if (rc)
 938		goto release_irq;
 939
 940	vu_dev->irq = irq;
 941
 942	goto out;
 943
 944release_irq:
 945	um_free_irq(irq, vq);
 946close_both:
 947	os_close_file(call_fds[0]);
 948out:
 949	/* Close (unused) write end of call fds */
 950	os_close_file(call_fds[1]);
 951
 952	return rc;
 953}
 954
 955static struct virtqueue *vu_setup_vq(struct virtio_device *vdev,
 956				     unsigned index, vq_callback_t *callback,
 957				     const char *name, bool ctx)
 958{
 959	struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
 960	struct platform_device *pdev = vu_dev->pdev;
 961	struct virtio_uml_vq_info *info;
 962	struct virtqueue *vq;
 963	int num = MAX_SUPPORTED_QUEUE_SIZE;
 964	int rc;
 965
 966	info = kzalloc(sizeof(*info), GFP_KERNEL);
 967	if (!info) {
 968		rc = -ENOMEM;
 969		goto error_kzalloc;
 970	}
 971	snprintf(info->name, sizeof(info->name), "%s.%d-%s", pdev->name,
 972		 pdev->id, name);
 973
 974	vq = vring_create_virtqueue(index, num, PAGE_SIZE, vdev, true, true,
 975				    ctx, vu_notify, callback, info->name);
 976	if (!vq) {
 977		rc = -ENOMEM;
 978		goto error_create;
 979	}
 980	vq->priv = info;
 981	vq->num_max = num;
 982	num = virtqueue_get_vring_size(vq);
 983
 984	if (vu_dev->protocol_features &
 985			BIT_ULL(VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS)) {
 986		info->kick_fd = -1;
 987	} else {
 988		rc = os_eventfd(0, 0);
 989		if (rc < 0)
 990			goto error_kick;
 991		info->kick_fd = rc;
 992	}
 993
 994	rc = vu_setup_vq_call_fd(vu_dev, vq);
 995	if (rc)
 996		goto error_call;
 997
 998	rc = vhost_user_set_vring_num(vu_dev, index, num);
 999	if (rc)
1000		goto error_setup;
1001
1002	rc = vhost_user_set_vring_base(vu_dev, index, 0);
1003	if (rc)
1004		goto error_setup;
1005
1006	rc = vhost_user_set_vring_addr(vu_dev, index,
1007				       virtqueue_get_desc_addr(vq),
1008				       virtqueue_get_used_addr(vq),
1009				       virtqueue_get_avail_addr(vq),
1010				       (u64) -1);
1011	if (rc)
1012		goto error_setup;
1013
1014	return vq;
1015
1016error_setup:
1017	if (info->call_fd >= 0) {
1018		um_free_irq(vu_dev->irq, vq);
1019		os_close_file(info->call_fd);
1020	}
1021error_call:
1022	if (info->kick_fd >= 0)
1023		os_close_file(info->kick_fd);
1024error_kick:
1025	vring_del_virtqueue(vq);
1026error_create:
1027	kfree(info);
1028error_kzalloc:
1029	return ERR_PTR(rc);
1030}
1031
1032static int vu_find_vqs(struct virtio_device *vdev, unsigned nvqs,
1033		       struct virtqueue *vqs[],
1034		       struct virtqueue_info vqs_info[],
1035		       struct irq_affinity *desc)
1036{
1037	struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
1038	int i, queue_idx = 0, rc;
1039	struct virtqueue *vq;
1040
1041	/* not supported for now */
1042	if (WARN(nvqs > 64 || nvqs > vu_dev->max_vqs,
1043		 "%d VQs requested, only up to 64 or %lld supported\n",
1044		 nvqs, vu_dev->max_vqs))
1045		return -EINVAL;
1046
1047	rc = vhost_user_set_mem_table(vu_dev);
1048	if (rc)
1049		return rc;
1050
1051	for (i = 0; i < nvqs; ++i) {
1052		struct virtqueue_info *vqi = &vqs_info[i];
1053
1054		if (!vqi->name) {
1055			vqs[i] = NULL;
1056			continue;
1057		}
1058
1059		vqs[i] = vu_setup_vq(vdev, queue_idx++, vqi->callback,
1060				     vqi->name, vqi->ctx);
1061		if (IS_ERR(vqs[i])) {
1062			rc = PTR_ERR(vqs[i]);
1063			goto error_setup;
1064		}
1065	}
1066
1067	list_for_each_entry(vq, &vdev->vqs, list) {
1068		struct virtio_uml_vq_info *info = vq->priv;
1069
1070		if (info->kick_fd >= 0) {
1071			rc = vhost_user_set_vring_kick(vu_dev, vq->index,
1072						       info->kick_fd);
1073			if (rc)
1074				goto error_setup;
1075		}
1076
1077		rc = vhost_user_set_vring_enable(vu_dev, vq->index, true);
1078		if (rc)
1079			goto error_setup;
1080	}
1081
1082	return 0;
1083
1084error_setup:
1085	vu_del_vqs(vdev);
1086	return rc;
1087}
1088
1089static u64 vu_get_features(struct virtio_device *vdev)
1090{
1091	struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
1092
1093	return vu_dev->features;
1094}
1095
1096static int vu_finalize_features(struct virtio_device *vdev)
1097{
1098	struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
1099	u64 supported = vdev->features & VHOST_USER_SUPPORTED_F;
1100
1101	vring_transport_features(vdev);
1102	vu_dev->features = vdev->features | supported;
1103
1104	return vhost_user_set_features(vu_dev, vu_dev->features);
1105}
1106
1107static const char *vu_bus_name(struct virtio_device *vdev)
1108{
1109	struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
1110
1111	return vu_dev->pdev->name;
1112}
1113
1114static const struct virtio_config_ops virtio_uml_config_ops = {
1115	.get = vu_get,
1116	.set = vu_set,
1117	.get_status = vu_get_status,
1118	.set_status = vu_set_status,
1119	.reset = vu_reset,
1120	.find_vqs = vu_find_vqs,
1121	.del_vqs = vu_del_vqs,
1122	.get_features = vu_get_features,
1123	.finalize_features = vu_finalize_features,
1124	.bus_name = vu_bus_name,
1125};
1126
1127static void virtio_uml_release_dev(struct device *d)
1128{
1129	struct virtio_device *vdev =
1130			container_of(d, struct virtio_device, dev);
1131	struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
1132
1133	time_travel_propagate_time();
1134
1135	/* might not have been opened due to not negotiating the feature */
1136	if (vu_dev->req_fd >= 0) {
1137		um_free_irq(vu_dev->irq, vu_dev);
1138		os_close_file(vu_dev->req_fd);
1139	}
1140
1141	os_close_file(vu_dev->sock);
1142	kfree(vu_dev);
1143}
1144
1145void virtio_uml_set_no_vq_suspend(struct virtio_device *vdev,
1146				  bool no_vq_suspend)
1147{
1148	struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
1149
1150	if (WARN_ON(vdev->config != &virtio_uml_config_ops))
1151		return;
1152
1153	vu_dev->no_vq_suspend = no_vq_suspend;
1154	dev_info(&vdev->dev, "%sabled VQ suspend\n",
1155		 no_vq_suspend ? "dis" : "en");
1156}
1157
1158static void vu_of_conn_broken(struct work_struct *wk)
1159{
1160	struct virtio_uml_platform_data *pdata;
1161	struct virtio_uml_device *vu_dev;
1162
1163	pdata = container_of(wk, struct virtio_uml_platform_data, conn_broken_wk);
1164
1165	vu_dev = platform_get_drvdata(pdata->pdev);
1166
1167	virtio_break_device(&vu_dev->vdev);
1168
1169	/*
1170	 * We can't remove the device from the devicetree so the only thing we
1171	 * can do is warn.
1172	 */
1173	WARN_ON(1);
1174}
1175
1176/* Platform device */
1177
1178static struct virtio_uml_platform_data *
1179virtio_uml_create_pdata(struct platform_device *pdev)
1180{
1181	struct device_node *np = pdev->dev.of_node;
1182	struct virtio_uml_platform_data *pdata;
1183	int ret;
1184
1185	if (!np)
1186		return ERR_PTR(-EINVAL);
1187
1188	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
1189	if (!pdata)
1190		return ERR_PTR(-ENOMEM);
1191
1192	INIT_WORK(&pdata->conn_broken_wk, vu_of_conn_broken);
1193	pdata->pdev = pdev;
1194
1195	ret = of_property_read_string(np, "socket-path", &pdata->socket_path);
1196	if (ret)
1197		return ERR_PTR(ret);
1198
1199	ret = of_property_read_u32(np, "virtio-device-id",
1200				   &pdata->virtio_device_id);
1201	if (ret)
1202		return ERR_PTR(ret);
1203
1204	return pdata;
1205}
1206
1207static int virtio_uml_probe(struct platform_device *pdev)
1208{
1209	struct virtio_uml_platform_data *pdata = pdev->dev.platform_data;
1210	struct virtio_uml_device *vu_dev;
1211	int rc;
1212
1213	if (!pdata) {
1214		pdata = virtio_uml_create_pdata(pdev);
1215		if (IS_ERR(pdata))
1216			return PTR_ERR(pdata);
1217	}
1218
1219	vu_dev = kzalloc(sizeof(*vu_dev), GFP_KERNEL);
1220	if (!vu_dev)
1221		return -ENOMEM;
1222
1223	vu_dev->pdata = pdata;
1224	vu_dev->vdev.dev.parent = &pdev->dev;
1225	vu_dev->vdev.dev.release = virtio_uml_release_dev;
1226	vu_dev->vdev.config = &virtio_uml_config_ops;
1227	vu_dev->vdev.id.device = pdata->virtio_device_id;
1228	vu_dev->vdev.id.vendor = VIRTIO_DEV_ANY_ID;
1229	vu_dev->pdev = pdev;
1230	vu_dev->req_fd = -1;
1231	vu_dev->irq = UM_IRQ_ALLOC;
1232
1233	time_travel_propagate_time();
1234
1235	do {
1236		rc = os_connect_socket(pdata->socket_path);
1237	} while (rc == -EINTR);
1238	if (rc < 0)
1239		goto error_free;
1240	vu_dev->sock = rc;
1241
1242	spin_lock_init(&vu_dev->sock_lock);
1243
1244	rc = vhost_user_init(vu_dev);
1245	if (rc)
1246		goto error_init;
1247
1248	platform_set_drvdata(pdev, vu_dev);
1249
1250	device_set_wakeup_capable(&vu_dev->vdev.dev, true);
1251
1252	rc = register_virtio_device(&vu_dev->vdev);
1253	if (rc)
1254		put_device(&vu_dev->vdev.dev);
1255	vu_dev->registered = 1;
1256	return rc;
1257
1258error_init:
1259	os_close_file(vu_dev->sock);
1260error_free:
1261	kfree(vu_dev);
1262	return rc;
1263}
1264
1265static void virtio_uml_remove(struct platform_device *pdev)
1266{
1267	struct virtio_uml_device *vu_dev = platform_get_drvdata(pdev);
1268
1269	unregister_virtio_device(&vu_dev->vdev);
1270}
1271
1272/* Command line device list */
1273
1274static void vu_cmdline_release_dev(struct device *d)
1275{
1276}
1277
1278static struct device vu_cmdline_parent = {
1279	.init_name = "virtio-uml-cmdline",
1280	.release = vu_cmdline_release_dev,
1281};
1282
1283static bool vu_cmdline_parent_registered;
1284static int vu_cmdline_id;
1285
1286static int vu_unregister_cmdline_device(struct device *dev, void *data)
1287{
1288	struct platform_device *pdev = to_platform_device(dev);
1289	struct virtio_uml_platform_data *pdata = pdev->dev.platform_data;
1290
1291	kfree(pdata->socket_path);
1292	platform_device_unregister(pdev);
1293	return 0;
1294}
1295
1296static void vu_conn_broken(struct work_struct *wk)
1297{
1298	struct virtio_uml_platform_data *pdata;
1299	struct virtio_uml_device *vu_dev;
1300
1301	pdata = container_of(wk, struct virtio_uml_platform_data, conn_broken_wk);
1302
1303	vu_dev = platform_get_drvdata(pdata->pdev);
1304
1305	virtio_break_device(&vu_dev->vdev);
1306
1307	vu_unregister_cmdline_device(&pdata->pdev->dev, NULL);
1308}
1309
1310static int vu_cmdline_set(const char *device, const struct kernel_param *kp)
1311{
1312	const char *ids = strchr(device, ':');
1313	unsigned int virtio_device_id;
1314	int processed, consumed, err;
1315	char *socket_path;
1316	struct virtio_uml_platform_data pdata, *ppdata;
1317	struct platform_device *pdev;
1318
1319	if (!ids || ids == device)
1320		return -EINVAL;
1321
1322	processed = sscanf(ids, ":%u%n:%d%n",
1323			   &virtio_device_id, &consumed,
1324			   &vu_cmdline_id, &consumed);
1325
1326	if (processed < 1 || ids[consumed])
1327		return -EINVAL;
1328
1329	if (!vu_cmdline_parent_registered) {
1330		err = device_register(&vu_cmdline_parent);
1331		if (err) {
1332			pr_err("Failed to register parent device!\n");
1333			put_device(&vu_cmdline_parent);
1334			return err;
1335		}
1336		vu_cmdline_parent_registered = true;
1337	}
1338
1339	socket_path = kmemdup_nul(device, ids - device, GFP_KERNEL);
1340	if (!socket_path)
1341		return -ENOMEM;
1342
1343	pdata.virtio_device_id = (u32) virtio_device_id;
1344	pdata.socket_path = socket_path;
1345
1346	pr_info("Registering device virtio-uml.%d id=%d at %s\n",
1347		vu_cmdline_id, virtio_device_id, socket_path);
1348
1349	pdev = platform_device_register_data(&vu_cmdline_parent, "virtio-uml",
1350					     vu_cmdline_id++, &pdata,
1351					     sizeof(pdata));
1352	err = PTR_ERR_OR_ZERO(pdev);
1353	if (err)
1354		goto free;
1355
1356	ppdata = pdev->dev.platform_data;
1357	ppdata->pdev = pdev;
1358	INIT_WORK(&ppdata->conn_broken_wk, vu_conn_broken);
1359
1360	return 0;
1361
1362free:
1363	kfree(socket_path);
1364	return err;
1365}
1366
1367static int vu_cmdline_get_device(struct device *dev, void *data)
1368{
1369	struct platform_device *pdev = to_platform_device(dev);
1370	struct virtio_uml_platform_data *pdata = pdev->dev.platform_data;
1371	char *buffer = data;
1372	unsigned int len = strlen(buffer);
1373
1374	snprintf(buffer + len, PAGE_SIZE - len, "%s:%d:%d\n",
1375		 pdata->socket_path, pdata->virtio_device_id, pdev->id);
1376	return 0;
1377}
1378
1379static int vu_cmdline_get(char *buffer, const struct kernel_param *kp)
1380{
1381	buffer[0] = '\0';
1382	if (vu_cmdline_parent_registered)
1383		device_for_each_child(&vu_cmdline_parent, buffer,
1384				      vu_cmdline_get_device);
1385	return strlen(buffer) + 1;
1386}
1387
1388static const struct kernel_param_ops vu_cmdline_param_ops = {
1389	.set = vu_cmdline_set,
1390	.get = vu_cmdline_get,
1391};
1392
1393device_param_cb(device, &vu_cmdline_param_ops, NULL, S_IRUSR);
1394__uml_help(vu_cmdline_param_ops,
1395"virtio_uml.device=<socket>:<virtio_id>[:<platform_id>]\n"
1396"    Configure a virtio device over a vhost-user socket.\n"
1397"    See virtio_ids.h for a list of possible virtio device id values.\n"
1398"    Optionally use a specific platform_device id.\n\n"
1399);
1400
1401
1402static void vu_unregister_cmdline_devices(void)
1403{
1404	if (vu_cmdline_parent_registered) {
1405		device_for_each_child(&vu_cmdline_parent, NULL,
1406				      vu_unregister_cmdline_device);
1407		device_unregister(&vu_cmdline_parent);
1408		vu_cmdline_parent_registered = false;
1409	}
1410}
1411
1412/* Platform driver */
1413
1414static const struct of_device_id virtio_uml_match[] = {
1415	{ .compatible = "virtio,uml", },
1416	{ }
1417};
1418MODULE_DEVICE_TABLE(of, virtio_uml_match);
1419
1420static int virtio_uml_suspend(struct platform_device *pdev, pm_message_t state)
1421{
1422	struct virtio_uml_device *vu_dev = platform_get_drvdata(pdev);
1423
1424	if (!vu_dev->no_vq_suspend) {
1425		struct virtqueue *vq;
1426
1427		virtio_device_for_each_vq((&vu_dev->vdev), vq) {
1428			struct virtio_uml_vq_info *info = vq->priv;
1429
1430			info->suspended = true;
1431			vhost_user_set_vring_enable(vu_dev, vq->index, false);
1432		}
1433	}
1434
1435	if (!device_may_wakeup(&vu_dev->vdev.dev)) {
1436		vu_dev->suspended = true;
1437		return 0;
1438	}
1439
1440	return irq_set_irq_wake(vu_dev->irq, 1);
1441}
1442
1443static int virtio_uml_resume(struct platform_device *pdev)
1444{
1445	struct virtio_uml_device *vu_dev = platform_get_drvdata(pdev);
1446
1447	if (!vu_dev->no_vq_suspend) {
1448		struct virtqueue *vq;
1449
1450		virtio_device_for_each_vq((&vu_dev->vdev), vq) {
1451			struct virtio_uml_vq_info *info = vq->priv;
1452
1453			info->suspended = false;
1454			vhost_user_set_vring_enable(vu_dev, vq->index, true);
1455		}
1456	}
1457
1458	vu_dev->suspended = false;
1459
1460	if (!device_may_wakeup(&vu_dev->vdev.dev))
1461		return 0;
1462
1463	return irq_set_irq_wake(vu_dev->irq, 0);
1464}
1465
1466static struct platform_driver virtio_uml_driver = {
1467	.probe = virtio_uml_probe,
1468	.remove = virtio_uml_remove,
1469	.driver = {
1470		.name = "virtio-uml",
1471		.of_match_table = virtio_uml_match,
1472	},
1473	.suspend = virtio_uml_suspend,
1474	.resume = virtio_uml_resume,
1475};
1476
1477static int __init virtio_uml_init(void)
1478{
1479	return platform_driver_register(&virtio_uml_driver);
1480}
1481
1482static void __exit virtio_uml_exit(void)
1483{
1484	platform_driver_unregister(&virtio_uml_driver);
1485	vu_unregister_cmdline_devices();
1486}
1487
1488module_init(virtio_uml_init);
1489module_exit(virtio_uml_exit);
1490__uml_exitcall(virtio_uml_exit);
1491
1492MODULE_DESCRIPTION("UML driver for vhost-user virtio devices");
1493MODULE_LICENSE("GPL");