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