1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2011, Bryan Venteicher <bryanv@FreeBSD.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice unmodified, this list of conditions, and the following 12 * disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /* Driver for VirtIO memory balloon devices. */ 30 31 #include <sys/cdefs.h> 32 __FBSDID("$FreeBSD$"); 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/kernel.h> 37 #include <sys/endian.h> 38 #include <sys/kthread.h> 39 #include <sys/malloc.h> 40 #include <sys/module.h> 41 #include <sys/sglist.h> 42 #include <sys/sysctl.h> 43 #include <sys/lock.h> 44 #include <sys/mutex.h> 45 #include <sys/queue.h> 46 47 #include <vm/vm.h> 48 #include <vm/vm_page.h> 49 50 #include <machine/bus.h> 51 #include <machine/resource.h> 52 #include <sys/bus.h> 53 #include <sys/rman.h> 54 55 #include <dev/virtio/virtio.h> 56 #include <dev/virtio/virtqueue.h> 57 #include <dev/virtio/balloon/virtio_balloon.h> 58 59 #include "virtio_if.h" 60 61 struct vtballoon_softc { 62 device_t vtballoon_dev; 63 struct mtx vtballoon_mtx; 64 uint64_t vtballoon_features; 65 uint32_t vtballoon_flags; 66 #define VTBALLOON_FLAG_DETACH 0x01 67 68 struct virtqueue *vtballoon_inflate_vq; 69 struct virtqueue *vtballoon_deflate_vq; 70 71 uint32_t vtballoon_desired_npages; 72 uint32_t vtballoon_current_npages; 73 TAILQ_HEAD(,vm_page) vtballoon_pages; 74 75 struct thread *vtballoon_td; 76 uint32_t *vtballoon_page_frames; 77 int vtballoon_timeout; 78 }; 79 80 static struct virtio_feature_desc vtballoon_feature_desc[] = { 81 { VIRTIO_BALLOON_F_MUST_TELL_HOST, "MustTellHost" }, 82 { VIRTIO_BALLOON_F_STATS_VQ, "StatsVq" }, 83 { VIRTIO_BALLOON_F_DEFLATE_ON_OOM, "DeflateOnOOM" }, 84 85 { 0, NULL } 86 }; 87 88 static int vtballoon_probe(device_t); 89 static int vtballoon_attach(device_t); 90 static int vtballoon_detach(device_t); 91 static int vtballoon_config_change(device_t); 92 93 static int vtballoon_negotiate_features(struct vtballoon_softc *); 94 static int vtballoon_setup_features(struct vtballoon_softc *); 95 static int vtballoon_alloc_virtqueues(struct vtballoon_softc *); 96 97 static void vtballoon_vq_intr(void *); 98 99 static void vtballoon_inflate(struct vtballoon_softc *, int); 100 static void vtballoon_deflate(struct vtballoon_softc *, int); 101 102 static void vtballoon_send_page_frames(struct vtballoon_softc *, 103 struct virtqueue *, int); 104 105 static void vtballoon_pop(struct vtballoon_softc *); 106 static void vtballoon_stop(struct vtballoon_softc *); 107 108 static vm_page_t 109 vtballoon_alloc_page(struct vtballoon_softc *); 110 static void vtballoon_free_page(struct vtballoon_softc *, vm_page_t); 111 112 static int vtballoon_sleep(struct vtballoon_softc *); 113 static void vtballoon_thread(void *); 114 static void vtballoon_setup_sysctl(struct vtballoon_softc *); 115 116 #define vtballoon_modern(_sc) \ 117 (((_sc)->vtballoon_features & VIRTIO_F_VERSION_1) != 0) 118 119 /* Features desired/implemented by this driver. */ 120 #define VTBALLOON_FEATURES VIRTIO_BALLOON_F_MUST_TELL_HOST 121 122 /* Timeout between retries when the balloon needs inflating. */ 123 #define VTBALLOON_LOWMEM_TIMEOUT hz 124 125 /* 126 * Maximum number of pages we'll request to inflate or deflate 127 * the balloon in one virtqueue request. Both Linux and NetBSD 128 * have settled on 256, doing up to 1MB at a time. 129 */ 130 #define VTBALLOON_PAGES_PER_REQUEST 256 131 132 /* Must be able to fix all pages frames in one page (segment). */ 133 CTASSERT(VTBALLOON_PAGES_PER_REQUEST * sizeof(uint32_t) <= PAGE_SIZE); 134 135 #define VTBALLOON_MTX(_sc) &(_sc)->vtballoon_mtx 136 #define VTBALLOON_LOCK_INIT(_sc, _name) mtx_init(VTBALLOON_MTX((_sc)), _name, \ 137 "VirtIO Balloon Lock", MTX_DEF) 138 #define VTBALLOON_LOCK(_sc) mtx_lock(VTBALLOON_MTX((_sc))) 139 #define VTBALLOON_UNLOCK(_sc) mtx_unlock(VTBALLOON_MTX((_sc))) 140 #define VTBALLOON_LOCK_DESTROY(_sc) mtx_destroy(VTBALLOON_MTX((_sc))) 141 142 static device_method_t vtballoon_methods[] = { 143 /* Device methods. */ 144 DEVMETHOD(device_probe, vtballoon_probe), 145 DEVMETHOD(device_attach, vtballoon_attach), 146 DEVMETHOD(device_detach, vtballoon_detach), 147 148 /* VirtIO methods. */ 149 DEVMETHOD(virtio_config_change, vtballoon_config_change), 150 151 DEVMETHOD_END 152 }; 153 154 static driver_t vtballoon_driver = { 155 "vtballoon", 156 vtballoon_methods, 157 sizeof(struct vtballoon_softc) 158 }; 159 static devclass_t vtballoon_devclass; 160 161 VIRTIO_DRIVER_MODULE(virtio_balloon, vtballoon_driver, 162 vtballoon_devclass, 0, 0); 163 MODULE_VERSION(virtio_balloon, 1); 164 MODULE_DEPEND(virtio_balloon, virtio, 1, 1, 1); 165 166 VIRTIO_SIMPLE_PNPINFO(virtio_balloon, VIRTIO_ID_BALLOON, 167 "VirtIO Balloon Adapter"); 168 169 static int 170 vtballoon_probe(device_t dev) 171 { 172 return (VIRTIO_SIMPLE_PROBE(dev, virtio_balloon)); 173 } 174 175 static int 176 vtballoon_attach(device_t dev) 177 { 178 struct vtballoon_softc *sc; 179 int error; 180 181 sc = device_get_softc(dev); 182 sc->vtballoon_dev = dev; 183 virtio_set_feature_desc(dev, vtballoon_feature_desc); 184 185 VTBALLOON_LOCK_INIT(sc, device_get_nameunit(dev)); 186 TAILQ_INIT(&sc->vtballoon_pages); 187 188 vtballoon_setup_sysctl(sc); 189 190 error = vtballoon_setup_features(sc); 191 if (error) { 192 device_printf(dev, "cannot setup features\n"); 193 goto fail; 194 } 195 196 sc->vtballoon_page_frames = malloc(VTBALLOON_PAGES_PER_REQUEST * 197 sizeof(uint32_t), M_DEVBUF, M_NOWAIT | M_ZERO); 198 if (sc->vtballoon_page_frames == NULL) { 199 error = ENOMEM; 200 device_printf(dev, 201 "cannot allocate page frame request array\n"); 202 goto fail; 203 } 204 205 error = vtballoon_alloc_virtqueues(sc); 206 if (error) { 207 device_printf(dev, "cannot allocate virtqueues\n"); 208 goto fail; 209 } 210 211 error = virtio_setup_intr(dev, INTR_TYPE_MISC); 212 if (error) { 213 device_printf(dev, "cannot setup virtqueue interrupts\n"); 214 goto fail; 215 } 216 217 error = kthread_add(vtballoon_thread, sc, NULL, &sc->vtballoon_td, 218 0, 0, "virtio_balloon"); 219 if (error) { 220 device_printf(dev, "cannot create balloon kthread\n"); 221 goto fail; 222 } 223 224 virtqueue_enable_intr(sc->vtballoon_inflate_vq); 225 virtqueue_enable_intr(sc->vtballoon_deflate_vq); 226 227 fail: 228 if (error) 229 vtballoon_detach(dev); 230 231 return (error); 232 } 233 234 static int 235 vtballoon_detach(device_t dev) 236 { 237 struct vtballoon_softc *sc; 238 239 sc = device_get_softc(dev); 240 241 if (sc->vtballoon_td != NULL) { 242 VTBALLOON_LOCK(sc); 243 sc->vtballoon_flags |= VTBALLOON_FLAG_DETACH; 244 wakeup_one(sc); 245 msleep(sc->vtballoon_td, VTBALLOON_MTX(sc), 0, "vtbdth", 0); 246 VTBALLOON_UNLOCK(sc); 247 248 sc->vtballoon_td = NULL; 249 } 250 251 if (device_is_attached(dev)) { 252 vtballoon_pop(sc); 253 vtballoon_stop(sc); 254 } 255 256 if (sc->vtballoon_page_frames != NULL) { 257 free(sc->vtballoon_page_frames, M_DEVBUF); 258 sc->vtballoon_page_frames = NULL; 259 } 260 261 VTBALLOON_LOCK_DESTROY(sc); 262 263 return (0); 264 } 265 266 static int 267 vtballoon_config_change(device_t dev) 268 { 269 struct vtballoon_softc *sc; 270 271 sc = device_get_softc(dev); 272 273 VTBALLOON_LOCK(sc); 274 wakeup_one(sc); 275 VTBALLOON_UNLOCK(sc); 276 277 return (1); 278 } 279 280 static int 281 vtballoon_negotiate_features(struct vtballoon_softc *sc) 282 { 283 device_t dev; 284 uint64_t features; 285 286 dev = sc->vtballoon_dev; 287 features = VTBALLOON_FEATURES; 288 289 sc->vtballoon_features = virtio_negotiate_features(dev, features); 290 return (virtio_finalize_features(dev)); 291 } 292 293 static int 294 vtballoon_setup_features(struct vtballoon_softc *sc) 295 { 296 int error; 297 298 error = vtballoon_negotiate_features(sc); 299 if (error) 300 return (error); 301 302 return (0); 303 } 304 305 static int 306 vtballoon_alloc_virtqueues(struct vtballoon_softc *sc) 307 { 308 device_t dev; 309 struct vq_alloc_info vq_info[2]; 310 int nvqs; 311 312 dev = sc->vtballoon_dev; 313 nvqs = 2; 314 315 VQ_ALLOC_INFO_INIT(&vq_info[0], 0, vtballoon_vq_intr, sc, 316 &sc->vtballoon_inflate_vq, "%s inflate", device_get_nameunit(dev)); 317 318 VQ_ALLOC_INFO_INIT(&vq_info[1], 0, vtballoon_vq_intr, sc, 319 &sc->vtballoon_deflate_vq, "%s deflate", device_get_nameunit(dev)); 320 321 return (virtio_alloc_virtqueues(dev, 0, nvqs, vq_info)); 322 } 323 324 static void 325 vtballoon_vq_intr(void *xsc) 326 { 327 struct vtballoon_softc *sc; 328 329 sc = xsc; 330 331 VTBALLOON_LOCK(sc); 332 wakeup_one(sc); 333 VTBALLOON_UNLOCK(sc); 334 } 335 336 static void 337 vtballoon_inflate(struct vtballoon_softc *sc, int npages) 338 { 339 struct virtqueue *vq; 340 vm_page_t m; 341 int i; 342 343 vq = sc->vtballoon_inflate_vq; 344 345 if (npages > VTBALLOON_PAGES_PER_REQUEST) 346 npages = VTBALLOON_PAGES_PER_REQUEST; 347 348 for (i = 0; i < npages; i++) { 349 if ((m = vtballoon_alloc_page(sc)) == NULL) { 350 sc->vtballoon_timeout = VTBALLOON_LOWMEM_TIMEOUT; 351 break; 352 } 353 354 sc->vtballoon_page_frames[i] = 355 VM_PAGE_TO_PHYS(m) >> VIRTIO_BALLOON_PFN_SHIFT; 356 357 KASSERT(m->a.queue == PQ_NONE, 358 ("%s: allocated page %p on queue", __func__, m)); 359 TAILQ_INSERT_TAIL(&sc->vtballoon_pages, m, plinks.q); 360 } 361 362 if (i > 0) 363 vtballoon_send_page_frames(sc, vq, i); 364 } 365 366 static void 367 vtballoon_deflate(struct vtballoon_softc *sc, int npages) 368 { 369 TAILQ_HEAD(, vm_page) free_pages; 370 struct virtqueue *vq; 371 vm_page_t m; 372 int i; 373 374 vq = sc->vtballoon_deflate_vq; 375 TAILQ_INIT(&free_pages); 376 377 if (npages > VTBALLOON_PAGES_PER_REQUEST) 378 npages = VTBALLOON_PAGES_PER_REQUEST; 379 380 for (i = 0; i < npages; i++) { 381 m = TAILQ_FIRST(&sc->vtballoon_pages); 382 KASSERT(m != NULL, ("%s: no more pages to deflate", __func__)); 383 384 sc->vtballoon_page_frames[i] = 385 VM_PAGE_TO_PHYS(m) >> VIRTIO_BALLOON_PFN_SHIFT; 386 387 TAILQ_REMOVE(&sc->vtballoon_pages, m, plinks.q); 388 TAILQ_INSERT_TAIL(&free_pages, m, plinks.q); 389 } 390 391 if (i > 0) { 392 /* Always tell host first before freeing the pages. */ 393 vtballoon_send_page_frames(sc, vq, i); 394 395 while ((m = TAILQ_FIRST(&free_pages)) != NULL) { 396 TAILQ_REMOVE(&free_pages, m, plinks.q); 397 vtballoon_free_page(sc, m); 398 } 399 } 400 401 KASSERT((TAILQ_EMPTY(&sc->vtballoon_pages) && 402 sc->vtballoon_current_npages == 0) || 403 (!TAILQ_EMPTY(&sc->vtballoon_pages) && 404 sc->vtballoon_current_npages != 0), 405 ("%s: bogus page count %d", __func__, 406 sc->vtballoon_current_npages)); 407 } 408 409 static void 410 vtballoon_send_page_frames(struct vtballoon_softc *sc, struct virtqueue *vq, 411 int npages) 412 { 413 struct sglist sg; 414 struct sglist_seg segs[1]; 415 void *c; 416 int error; 417 418 sglist_init(&sg, 1, segs); 419 420 error = sglist_append(&sg, sc->vtballoon_page_frames, 421 npages * sizeof(uint32_t)); 422 KASSERT(error == 0, ("error adding page frames to sglist")); 423 424 error = virtqueue_enqueue(vq, vq, &sg, 1, 0); 425 KASSERT(error == 0, ("error enqueuing page frames to virtqueue")); 426 virtqueue_notify(vq); 427 428 /* 429 * Inflate and deflate operations are done synchronously. The 430 * interrupt handler will wake us up. 431 */ 432 VTBALLOON_LOCK(sc); 433 while ((c = virtqueue_dequeue(vq, NULL)) == NULL) 434 msleep(sc, VTBALLOON_MTX(sc), 0, "vtbspf", 0); 435 VTBALLOON_UNLOCK(sc); 436 437 KASSERT(c == vq, ("unexpected balloon operation response")); 438 } 439 440 static void 441 vtballoon_pop(struct vtballoon_softc *sc) 442 { 443 444 while (!TAILQ_EMPTY(&sc->vtballoon_pages)) 445 vtballoon_deflate(sc, sc->vtballoon_current_npages); 446 } 447 448 static void 449 vtballoon_stop(struct vtballoon_softc *sc) 450 { 451 452 virtqueue_disable_intr(sc->vtballoon_inflate_vq); 453 virtqueue_disable_intr(sc->vtballoon_deflate_vq); 454 455 virtio_stop(sc->vtballoon_dev); 456 } 457 458 static vm_page_t 459 vtballoon_alloc_page(struct vtballoon_softc *sc) 460 { 461 vm_page_t m; 462 463 m = vm_page_alloc_noobj(VM_ALLOC_NODUMP); 464 if (m != NULL) 465 sc->vtballoon_current_npages++; 466 467 return (m); 468 } 469 470 static void 471 vtballoon_free_page(struct vtballoon_softc *sc, vm_page_t m) 472 { 473 474 vm_page_free(m); 475 sc->vtballoon_current_npages--; 476 } 477 478 static uint32_t 479 vtballoon_desired_size(struct vtballoon_softc *sc) 480 { 481 uint32_t desired; 482 483 desired = virtio_read_dev_config_4(sc->vtballoon_dev, 484 offsetof(struct virtio_balloon_config, num_pages)); 485 486 if (vtballoon_modern(sc)) 487 return (desired); 488 else 489 return (le32toh(desired)); 490 } 491 492 static void 493 vtballoon_update_size(struct vtballoon_softc *sc) 494 { 495 uint32_t npages; 496 497 npages = sc->vtballoon_current_npages; 498 if (!vtballoon_modern(sc)) 499 npages = htole32(npages); 500 501 virtio_write_dev_config_4(sc->vtballoon_dev, 502 offsetof(struct virtio_balloon_config, actual), npages); 503 } 504 505 static int 506 vtballoon_sleep(struct vtballoon_softc *sc) 507 { 508 int rc, timeout; 509 uint32_t current, desired; 510 511 rc = 0; 512 current = sc->vtballoon_current_npages; 513 514 VTBALLOON_LOCK(sc); 515 for (;;) { 516 if (sc->vtballoon_flags & VTBALLOON_FLAG_DETACH) { 517 rc = 1; 518 break; 519 } 520 521 desired = vtballoon_desired_size(sc); 522 sc->vtballoon_desired_npages = desired; 523 524 /* 525 * If given, use non-zero timeout on the first time through 526 * the loop. On subsequent times, timeout will be zero so 527 * we will reevaluate the desired size of the balloon and 528 * break out to retry if needed. 529 */ 530 timeout = sc->vtballoon_timeout; 531 sc->vtballoon_timeout = 0; 532 533 if (current > desired) 534 break; 535 if (current < desired && timeout == 0) 536 break; 537 538 msleep(sc, VTBALLOON_MTX(sc), 0, "vtbslp", timeout); 539 } 540 VTBALLOON_UNLOCK(sc); 541 542 return (rc); 543 } 544 545 static void 546 vtballoon_thread(void *xsc) 547 { 548 struct vtballoon_softc *sc; 549 uint32_t current, desired; 550 551 sc = xsc; 552 553 for (;;) { 554 if (vtballoon_sleep(sc) != 0) 555 break; 556 557 current = sc->vtballoon_current_npages; 558 desired = sc->vtballoon_desired_npages; 559 560 if (desired != current) { 561 if (desired > current) 562 vtballoon_inflate(sc, desired - current); 563 else 564 vtballoon_deflate(sc, current - desired); 565 566 vtballoon_update_size(sc); 567 } 568 } 569 570 kthread_exit(); 571 } 572 573 static void 574 vtballoon_setup_sysctl(struct vtballoon_softc *sc) 575 { 576 device_t dev; 577 struct sysctl_ctx_list *ctx; 578 struct sysctl_oid *tree; 579 struct sysctl_oid_list *child; 580 581 dev = sc->vtballoon_dev; 582 ctx = device_get_sysctl_ctx(dev); 583 tree = device_get_sysctl_tree(dev); 584 child = SYSCTL_CHILDREN(tree); 585 586 SYSCTL_ADD_UINT(ctx, child, OID_AUTO, "desired", 587 CTLFLAG_RD, &sc->vtballoon_desired_npages, sizeof(uint32_t), 588 "Desired balloon size in pages"); 589 590 SYSCTL_ADD_UINT(ctx, child, OID_AUTO, "current", 591 CTLFLAG_RD, &sc->vtballoon_current_npages, sizeof(uint32_t), 592 "Current balloon size in pages"); 593 } 594