| 1 | /* Virtio ring implementation. |
| 2 | * |
| 3 | * Copyright 2007 Rusty Russell IBM Corporation |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License as published by |
| 7 | * the Free Software Foundation; either version 2 of the License, or |
| 8 | * (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program; if not, write to the Free Software |
| 17 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 18 | */ |
| 19 | #include <linux/virtio.h> |
| 20 | #include <linux/virtio_ring.h> |
| 21 | #include <linux/virtio_config.h> |
| 22 | #include <linux/device.h> |
| 23 | #include <linux/slab.h> |
| 24 | #include <linux/module.h> |
| 25 | #include <linux/hrtimer.h> |
| 26 | #include <linux/kmemleak.h> |
| 27 | #include <linux/dma-mapping.h> |
| 28 | #include <xen/xen.h> |
| 29 | |
| 30 | #ifdef DEBUG |
| 31 | /* For development, we want to crash whenever the ring is screwed. */ |
| 32 | #define BAD_RING(_vq, fmt, args...) \ |
| 33 | do { \ |
| 34 | dev_err(&(_vq)->vq.vdev->dev, \ |
| 35 | "%s:"fmt, (_vq)->vq.name, ##args); \ |
| 36 | BUG(); \ |
| 37 | } while (0) |
| 38 | /* Caller is supposed to guarantee no reentry. */ |
| 39 | #define START_USE(_vq) \ |
| 40 | do { \ |
| 41 | if ((_vq)->in_use) \ |
| 42 | panic("%s:in_use = %i\n", \ |
| 43 | (_vq)->vq.name, (_vq)->in_use); \ |
| 44 | (_vq)->in_use = __LINE__; \ |
| 45 | } while (0) |
| 46 | #define END_USE(_vq) \ |
| 47 | do { BUG_ON(!(_vq)->in_use); (_vq)->in_use = 0; } while(0) |
| 48 | #else |
| 49 | #define BAD_RING(_vq, fmt, args...) \ |
| 50 | do { \ |
| 51 | dev_err(&_vq->vq.vdev->dev, \ |
| 52 | "%s:"fmt, (_vq)->vq.name, ##args); \ |
| 53 | (_vq)->broken = true; \ |
| 54 | } while (0) |
| 55 | #define START_USE(vq) |
| 56 | #define END_USE(vq) |
| 57 | #endif |
| 58 | |
| 59 | struct vring_desc_state { |
| 60 | void *data; /* Data for callback. */ |
| 61 | struct vring_desc *indir_desc; /* Indirect descriptor, if any. */ |
| 62 | }; |
| 63 | |
| 64 | struct vring_virtqueue { |
| 65 | struct virtqueue vq; |
| 66 | |
| 67 | /* Actual memory layout for this queue */ |
| 68 | struct vring vring; |
| 69 | |
| 70 | /* Can we use weak barriers? */ |
| 71 | bool weak_barriers; |
| 72 | |
| 73 | /* Other side has made a mess, don't try any more. */ |
| 74 | bool broken; |
| 75 | |
| 76 | /* Host supports indirect buffers */ |
| 77 | bool indirect; |
| 78 | |
| 79 | /* Host publishes avail event idx */ |
| 80 | bool event; |
| 81 | |
| 82 | /* Head of free buffer list. */ |
| 83 | unsigned int free_head; |
| 84 | /* Number we've added since last sync. */ |
| 85 | unsigned int num_added; |
| 86 | |
| 87 | /* Last used index we've seen. */ |
| 88 | u16 last_used_idx; |
| 89 | |
| 90 | /* Last written value to avail->flags */ |
| 91 | u16 avail_flags_shadow; |
| 92 | |
| 93 | /* Last written value to avail->idx in guest byte order */ |
| 94 | u16 avail_idx_shadow; |
| 95 | |
| 96 | /* How to notify other side. FIXME: commonalize hcalls! */ |
| 97 | bool (*notify)(struct virtqueue *vq); |
| 98 | |
| 99 | /* DMA, allocation, and size information */ |
| 100 | bool we_own_ring; |
| 101 | size_t queue_size_in_bytes; |
| 102 | dma_addr_t queue_dma_addr; |
| 103 | |
| 104 | #ifdef DEBUG |
| 105 | /* They're supposed to lock for us. */ |
| 106 | unsigned int in_use; |
| 107 | |
| 108 | /* Figure out if their kicks are too delayed. */ |
| 109 | bool last_add_time_valid; |
| 110 | ktime_t last_add_time; |
| 111 | #endif |
| 112 | |
| 113 | /* Per-descriptor state. */ |
| 114 | struct vring_desc_state desc_state[]; |
| 115 | }; |
| 116 | |
| 117 | #define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq) |
| 118 | |
| 119 | /* |
| 120 | * Modern virtio devices have feature bits to specify whether they need a |
| 121 | * quirk and bypass the IOMMU. If not there, just use the DMA API. |
| 122 | * |
| 123 | * If there, the interaction between virtio and DMA API is messy. |
| 124 | * |
| 125 | * On most systems with virtio, physical addresses match bus addresses, |
| 126 | * and it doesn't particularly matter whether we use the DMA API. |
| 127 | * |
| 128 | * On some systems, including Xen and any system with a physical device |
| 129 | * that speaks virtio behind a physical IOMMU, we must use the DMA API |
| 130 | * for virtio DMA to work at all. |
| 131 | * |
| 132 | * On other systems, including SPARC and PPC64, virtio-pci devices are |
| 133 | * enumerated as though they are behind an IOMMU, but the virtio host |
| 134 | * ignores the IOMMU, so we must either pretend that the IOMMU isn't |
| 135 | * there or somehow map everything as the identity. |
| 136 | * |
| 137 | * For the time being, we preserve historic behavior and bypass the DMA |
| 138 | * API. |
| 139 | * |
| 140 | * TODO: install a per-device DMA ops structure that does the right thing |
| 141 | * taking into account all the above quirks, and use the DMA API |
| 142 | * unconditionally on data path. |
| 143 | */ |
| 144 | |
| 145 | static bool vring_use_dma_api(struct virtio_device *vdev) |
| 146 | { |
| 147 | if (!virtio_has_iommu_quirk(vdev)) |
| 148 | return true; |
| 149 | |
| 150 | /* Otherwise, we are left to guess. */ |
| 151 | /* |
| 152 | * In theory, it's possible to have a buggy QEMU-supposed |
| 153 | * emulated Q35 IOMMU and Xen enabled at the same time. On |
| 154 | * such a configuration, virtio has never worked and will |
| 155 | * not work without an even larger kludge. Instead, enable |
| 156 | * the DMA API if we're a Xen guest, which at least allows |
| 157 | * all of the sensible Xen configurations to work correctly. |
| 158 | */ |
| 159 | if (xen_domain()) |
| 160 | return true; |
| 161 | |
| 162 | return false; |
| 163 | } |
| 164 | |
| 165 | /* |
| 166 | * The DMA ops on various arches are rather gnarly right now, and |
| 167 | * making all of the arch DMA ops work on the vring device itself |
| 168 | * is a mess. For now, we use the parent device for DMA ops. |
| 169 | */ |
| 170 | static inline struct device *vring_dma_dev(const struct vring_virtqueue *vq) |
| 171 | { |
| 172 | return vq->vq.vdev->dev.parent; |
| 173 | } |
| 174 | |
| 175 | /* Map one sg entry. */ |
| 176 | static dma_addr_t vring_map_one_sg(const struct vring_virtqueue *vq, |
| 177 | struct scatterlist *sg, |
| 178 | enum dma_data_direction direction) |
| 179 | { |
| 180 | if (!vring_use_dma_api(vq->vq.vdev)) |
| 181 | return (dma_addr_t)sg_phys(sg); |
| 182 | |
| 183 | /* |
| 184 | * We can't use dma_map_sg, because we don't use scatterlists in |
| 185 | * the way it expects (we don't guarantee that the scatterlist |
| 186 | * will exist for the lifetime of the mapping). |
| 187 | */ |
| 188 | return dma_map_page(vring_dma_dev(vq), |
| 189 | sg_page(sg), sg->offset, sg->length, |
| 190 | direction); |
| 191 | } |
| 192 | |
| 193 | static dma_addr_t vring_map_single(const struct vring_virtqueue *vq, |
| 194 | void *cpu_addr, size_t size, |
| 195 | enum dma_data_direction direction) |
| 196 | { |
| 197 | if (!vring_use_dma_api(vq->vq.vdev)) |
| 198 | return (dma_addr_t)virt_to_phys(cpu_addr); |
| 199 | |
| 200 | return dma_map_single(vring_dma_dev(vq), |
| 201 | cpu_addr, size, direction); |
| 202 | } |
| 203 | |
| 204 | static void vring_unmap_one(const struct vring_virtqueue *vq, |
| 205 | struct vring_desc *desc) |
| 206 | { |
| 207 | u16 flags; |
| 208 | |
| 209 | if (!vring_use_dma_api(vq->vq.vdev)) |
| 210 | return; |
| 211 | |
| 212 | flags = virtio16_to_cpu(vq->vq.vdev, desc->flags); |
| 213 | |
| 214 | if (flags & VRING_DESC_F_INDIRECT) { |
| 215 | dma_unmap_single(vring_dma_dev(vq), |
| 216 | virtio64_to_cpu(vq->vq.vdev, desc->addr), |
| 217 | virtio32_to_cpu(vq->vq.vdev, desc->len), |
| 218 | (flags & VRING_DESC_F_WRITE) ? |
| 219 | DMA_FROM_DEVICE : DMA_TO_DEVICE); |
| 220 | } else { |
| 221 | dma_unmap_page(vring_dma_dev(vq), |
| 222 | virtio64_to_cpu(vq->vq.vdev, desc->addr), |
| 223 | virtio32_to_cpu(vq->vq.vdev, desc->len), |
| 224 | (flags & VRING_DESC_F_WRITE) ? |
| 225 | DMA_FROM_DEVICE : DMA_TO_DEVICE); |
| 226 | } |
| 227 | } |
| 228 | |
| 229 | static int vring_mapping_error(const struct vring_virtqueue *vq, |
| 230 | dma_addr_t addr) |
| 231 | { |
| 232 | if (!vring_use_dma_api(vq->vq.vdev)) |
| 233 | return 0; |
| 234 | |
| 235 | return dma_mapping_error(vring_dma_dev(vq), addr); |
| 236 | } |
| 237 | |
| 238 | static struct vring_desc *alloc_indirect(struct virtqueue *_vq, |
| 239 | unsigned int total_sg, gfp_t gfp) |
| 240 | { |
| 241 | struct vring_desc *desc; |
| 242 | unsigned int i; |
| 243 | |
| 244 | /* |
| 245 | * We require lowmem mappings for the descriptors because |
| 246 | * otherwise virt_to_phys will give us bogus addresses in the |
| 247 | * virtqueue. |
| 248 | */ |
| 249 | gfp &= ~__GFP_HIGHMEM; |
| 250 | |
| 251 | desc = kmalloc(total_sg * sizeof(struct vring_desc), gfp); |
| 252 | if (!desc) |
| 253 | return NULL; |
| 254 | |
| 255 | for (i = 0; i < total_sg; i++) |
| 256 | desc[i].next = cpu_to_virtio16(_vq->vdev, i + 1); |
| 257 | return desc; |
| 258 | } |
| 259 | |
| 260 | static inline int virtqueue_add(struct virtqueue *_vq, |
| 261 | struct scatterlist *sgs[], |
| 262 | unsigned int total_sg, |
| 263 | unsigned int out_sgs, |
| 264 | unsigned int in_sgs, |
| 265 | void *data, |
| 266 | gfp_t gfp) |
| 267 | { |
| 268 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 269 | struct scatterlist *sg; |
| 270 | struct vring_desc *desc; |
| 271 | unsigned int i, n, avail, descs_used, uninitialized_var(prev), err_idx; |
| 272 | int head; |
| 273 | bool indirect; |
| 274 | |
| 275 | START_USE(vq); |
| 276 | |
| 277 | BUG_ON(data == NULL); |
| 278 | |
| 279 | if (unlikely(vq->broken)) { |
| 280 | END_USE(vq); |
| 281 | return -EIO; |
| 282 | } |
| 283 | |
| 284 | #ifdef DEBUG |
| 285 | { |
| 286 | ktime_t now = ktime_get(); |
| 287 | |
| 288 | /* No kick or get, with .1 second between? Warn. */ |
| 289 | if (vq->last_add_time_valid) |
| 290 | WARN_ON(ktime_to_ms(ktime_sub(now, vq->last_add_time)) |
| 291 | > 100); |
| 292 | vq->last_add_time = now; |
| 293 | vq->last_add_time_valid = true; |
| 294 | } |
| 295 | #endif |
| 296 | |
| 297 | BUG_ON(total_sg > vq->vring.num); |
| 298 | BUG_ON(total_sg == 0); |
| 299 | |
| 300 | head = vq->free_head; |
| 301 | |
| 302 | /* If the host supports indirect descriptor tables, and we have multiple |
| 303 | * buffers, then go indirect. FIXME: tune this threshold */ |
| 304 | if (vq->indirect && total_sg > 1 && vq->vq.num_free) |
| 305 | desc = alloc_indirect(_vq, total_sg, gfp); |
| 306 | else |
| 307 | desc = NULL; |
| 308 | |
| 309 | if (desc) { |
| 310 | /* Use a single buffer which doesn't continue */ |
| 311 | indirect = true; |
| 312 | /* Set up rest to use this indirect table. */ |
| 313 | i = 0; |
| 314 | descs_used = 1; |
| 315 | } else { |
| 316 | indirect = false; |
| 317 | desc = vq->vring.desc; |
| 318 | i = head; |
| 319 | descs_used = total_sg; |
| 320 | } |
| 321 | |
| 322 | if (vq->vq.num_free < descs_used) { |
| 323 | pr_debug("Can't add buf len %i - avail = %i\n", |
| 324 | descs_used, vq->vq.num_free); |
| 325 | /* FIXME: for historical reasons, we force a notify here if |
| 326 | * there are outgoing parts to the buffer. Presumably the |
| 327 | * host should service the ring ASAP. */ |
| 328 | if (out_sgs) |
| 329 | vq->notify(&vq->vq); |
| 330 | if (indirect) |
| 331 | kfree(desc); |
| 332 | END_USE(vq); |
| 333 | return -ENOSPC; |
| 334 | } |
| 335 | |
| 336 | for (n = 0; n < out_sgs; n++) { |
| 337 | for (sg = sgs[n]; sg; sg = sg_next(sg)) { |
| 338 | dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_TO_DEVICE); |
| 339 | if (vring_mapping_error(vq, addr)) |
| 340 | goto unmap_release; |
| 341 | |
| 342 | desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT); |
| 343 | desc[i].addr = cpu_to_virtio64(_vq->vdev, addr); |
| 344 | desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length); |
| 345 | prev = i; |
| 346 | i = virtio16_to_cpu(_vq->vdev, desc[i].next); |
| 347 | } |
| 348 | } |
| 349 | for (; n < (out_sgs + in_sgs); n++) { |
| 350 | for (sg = sgs[n]; sg; sg = sg_next(sg)) { |
| 351 | dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_FROM_DEVICE); |
| 352 | if (vring_mapping_error(vq, addr)) |
| 353 | goto unmap_release; |
| 354 | |
| 355 | desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT | VRING_DESC_F_WRITE); |
| 356 | desc[i].addr = cpu_to_virtio64(_vq->vdev, addr); |
| 357 | desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length); |
| 358 | prev = i; |
| 359 | i = virtio16_to_cpu(_vq->vdev, desc[i].next); |
| 360 | } |
| 361 | } |
| 362 | /* Last one doesn't continue. */ |
| 363 | desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT); |
| 364 | |
| 365 | if (indirect) { |
| 366 | /* Now that the indirect table is filled in, map it. */ |
| 367 | dma_addr_t addr = vring_map_single( |
| 368 | vq, desc, total_sg * sizeof(struct vring_desc), |
| 369 | DMA_TO_DEVICE); |
| 370 | if (vring_mapping_error(vq, addr)) |
| 371 | goto unmap_release; |
| 372 | |
| 373 | vq->vring.desc[head].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_INDIRECT); |
| 374 | vq->vring.desc[head].addr = cpu_to_virtio64(_vq->vdev, addr); |
| 375 | |
| 376 | vq->vring.desc[head].len = cpu_to_virtio32(_vq->vdev, total_sg * sizeof(struct vring_desc)); |
| 377 | } |
| 378 | |
| 379 | /* We're using some buffers from the free list. */ |
| 380 | vq->vq.num_free -= descs_used; |
| 381 | |
| 382 | /* Update free pointer */ |
| 383 | if (indirect) |
| 384 | vq->free_head = virtio16_to_cpu(_vq->vdev, vq->vring.desc[head].next); |
| 385 | else |
| 386 | vq->free_head = i; |
| 387 | |
| 388 | /* Store token and indirect buffer state. */ |
| 389 | vq->desc_state[head].data = data; |
| 390 | if (indirect) |
| 391 | vq->desc_state[head].indir_desc = desc; |
| 392 | |
| 393 | /* Put entry in available array (but don't update avail->idx until they |
| 394 | * do sync). */ |
| 395 | avail = vq->avail_idx_shadow & (vq->vring.num - 1); |
| 396 | vq->vring.avail->ring[avail] = cpu_to_virtio16(_vq->vdev, head); |
| 397 | |
| 398 | /* Descriptors and available array need to be set before we expose the |
| 399 | * new available array entries. */ |
| 400 | virtio_wmb(vq->weak_barriers); |
| 401 | vq->avail_idx_shadow++; |
| 402 | vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev, vq->avail_idx_shadow); |
| 403 | vq->num_added++; |
| 404 | |
| 405 | pr_debug("Added buffer head %i to %p\n", head, vq); |
| 406 | END_USE(vq); |
| 407 | |
| 408 | /* This is very unlikely, but theoretically possible. Kick |
| 409 | * just in case. */ |
| 410 | if (unlikely(vq->num_added == (1 << 16) - 1)) |
| 411 | virtqueue_kick(_vq); |
| 412 | |
| 413 | return 0; |
| 414 | |
| 415 | unmap_release: |
| 416 | err_idx = i; |
| 417 | i = head; |
| 418 | |
| 419 | for (n = 0; n < total_sg; n++) { |
| 420 | if (i == err_idx) |
| 421 | break; |
| 422 | vring_unmap_one(vq, &desc[i]); |
| 423 | i = vq->vring.desc[i].next; |
| 424 | } |
| 425 | |
| 426 | vq->vq.num_free += total_sg; |
| 427 | |
| 428 | if (indirect) |
| 429 | kfree(desc); |
| 430 | |
| 431 | END_USE(vq); |
| 432 | return -EIO; |
| 433 | } |
| 434 | |
| 435 | /** |
| 436 | * virtqueue_add_sgs - expose buffers to other end |
| 437 | * @vq: the struct virtqueue we're talking about. |
| 438 | * @sgs: array of terminated scatterlists. |
| 439 | * @out_num: the number of scatterlists readable by other side |
| 440 | * @in_num: the number of scatterlists which are writable (after readable ones) |
| 441 | * @data: the token identifying the buffer. |
| 442 | * @gfp: how to do memory allocations (if necessary). |
| 443 | * |
| 444 | * Caller must ensure we don't call this with other virtqueue operations |
| 445 | * at the same time (except where noted). |
| 446 | * |
| 447 | * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). |
| 448 | */ |
| 449 | int virtqueue_add_sgs(struct virtqueue *_vq, |
| 450 | struct scatterlist *sgs[], |
| 451 | unsigned int out_sgs, |
| 452 | unsigned int in_sgs, |
| 453 | void *data, |
| 454 | gfp_t gfp) |
| 455 | { |
| 456 | unsigned int i, total_sg = 0; |
| 457 | |
| 458 | /* Count them first. */ |
| 459 | for (i = 0; i < out_sgs + in_sgs; i++) { |
| 460 | struct scatterlist *sg; |
| 461 | for (sg = sgs[i]; sg; sg = sg_next(sg)) |
| 462 | total_sg++; |
| 463 | } |
| 464 | return virtqueue_add(_vq, sgs, total_sg, out_sgs, in_sgs, data, gfp); |
| 465 | } |
| 466 | EXPORT_SYMBOL_GPL(virtqueue_add_sgs); |
| 467 | |
| 468 | /** |
| 469 | * virtqueue_add_outbuf - expose output buffers to other end |
| 470 | * @vq: the struct virtqueue we're talking about. |
| 471 | * @sg: scatterlist (must be well-formed and terminated!) |
| 472 | * @num: the number of entries in @sg readable by other side |
| 473 | * @data: the token identifying the buffer. |
| 474 | * @gfp: how to do memory allocations (if necessary). |
| 475 | * |
| 476 | * Caller must ensure we don't call this with other virtqueue operations |
| 477 | * at the same time (except where noted). |
| 478 | * |
| 479 | * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). |
| 480 | */ |
| 481 | int virtqueue_add_outbuf(struct virtqueue *vq, |
| 482 | struct scatterlist *sg, unsigned int num, |
| 483 | void *data, |
| 484 | gfp_t gfp) |
| 485 | { |
| 486 | return virtqueue_add(vq, &sg, num, 1, 0, data, gfp); |
| 487 | } |
| 488 | EXPORT_SYMBOL_GPL(virtqueue_add_outbuf); |
| 489 | |
| 490 | /** |
| 491 | * virtqueue_add_inbuf - expose input buffers to other end |
| 492 | * @vq: the struct virtqueue we're talking about. |
| 493 | * @sg: scatterlist (must be well-formed and terminated!) |
| 494 | * @num: the number of entries in @sg writable by other side |
| 495 | * @data: the token identifying the buffer. |
| 496 | * @gfp: how to do memory allocations (if necessary). |
| 497 | * |
| 498 | * Caller must ensure we don't call this with other virtqueue operations |
| 499 | * at the same time (except where noted). |
| 500 | * |
| 501 | * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). |
| 502 | */ |
| 503 | int virtqueue_add_inbuf(struct virtqueue *vq, |
| 504 | struct scatterlist *sg, unsigned int num, |
| 505 | void *data, |
| 506 | gfp_t gfp) |
| 507 | { |
| 508 | return virtqueue_add(vq, &sg, num, 0, 1, data, gfp); |
| 509 | } |
| 510 | EXPORT_SYMBOL_GPL(virtqueue_add_inbuf); |
| 511 | |
| 512 | /** |
| 513 | * virtqueue_kick_prepare - first half of split virtqueue_kick call. |
| 514 | * @vq: the struct virtqueue |
| 515 | * |
| 516 | * Instead of virtqueue_kick(), you can do: |
| 517 | * if (virtqueue_kick_prepare(vq)) |
| 518 | * virtqueue_notify(vq); |
| 519 | * |
| 520 | * This is sometimes useful because the virtqueue_kick_prepare() needs |
| 521 | * to be serialized, but the actual virtqueue_notify() call does not. |
| 522 | */ |
| 523 | bool virtqueue_kick_prepare(struct virtqueue *_vq) |
| 524 | { |
| 525 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 526 | u16 new, old; |
| 527 | bool needs_kick; |
| 528 | |
| 529 | START_USE(vq); |
| 530 | /* We need to expose available array entries before checking avail |
| 531 | * event. */ |
| 532 | virtio_mb(vq->weak_barriers); |
| 533 | |
| 534 | old = vq->avail_idx_shadow - vq->num_added; |
| 535 | new = vq->avail_idx_shadow; |
| 536 | vq->num_added = 0; |
| 537 | |
| 538 | #ifdef DEBUG |
| 539 | if (vq->last_add_time_valid) { |
| 540 | WARN_ON(ktime_to_ms(ktime_sub(ktime_get(), |
| 541 | vq->last_add_time)) > 100); |
| 542 | } |
| 543 | vq->last_add_time_valid = false; |
| 544 | #endif |
| 545 | |
| 546 | if (vq->event) { |
| 547 | needs_kick = vring_need_event(virtio16_to_cpu(_vq->vdev, vring_avail_event(&vq->vring)), |
| 548 | new, old); |
| 549 | } else { |
| 550 | needs_kick = !(vq->vring.used->flags & cpu_to_virtio16(_vq->vdev, VRING_USED_F_NO_NOTIFY)); |
| 551 | } |
| 552 | END_USE(vq); |
| 553 | return needs_kick; |
| 554 | } |
| 555 | EXPORT_SYMBOL_GPL(virtqueue_kick_prepare); |
| 556 | |
| 557 | /** |
| 558 | * virtqueue_notify - second half of split virtqueue_kick call. |
| 559 | * @vq: the struct virtqueue |
| 560 | * |
| 561 | * This does not need to be serialized. |
| 562 | * |
| 563 | * Returns false if host notify failed or queue is broken, otherwise true. |
| 564 | */ |
| 565 | bool virtqueue_notify(struct virtqueue *_vq) |
| 566 | { |
| 567 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 568 | |
| 569 | if (unlikely(vq->broken)) |
| 570 | return false; |
| 571 | |
| 572 | /* Prod other side to tell it about changes. */ |
| 573 | if (!vq->notify(_vq)) { |
| 574 | vq->broken = true; |
| 575 | return false; |
| 576 | } |
| 577 | return true; |
| 578 | } |
| 579 | EXPORT_SYMBOL_GPL(virtqueue_notify); |
| 580 | |
| 581 | /** |
| 582 | * virtqueue_kick - update after add_buf |
| 583 | * @vq: the struct virtqueue |
| 584 | * |
| 585 | * After one or more virtqueue_add_* calls, invoke this to kick |
| 586 | * the other side. |
| 587 | * |
| 588 | * Caller must ensure we don't call this with other virtqueue |
| 589 | * operations at the same time (except where noted). |
| 590 | * |
| 591 | * Returns false if kick failed, otherwise true. |
| 592 | */ |
| 593 | bool virtqueue_kick(struct virtqueue *vq) |
| 594 | { |
| 595 | if (virtqueue_kick_prepare(vq)) |
| 596 | return virtqueue_notify(vq); |
| 597 | return true; |
| 598 | } |
| 599 | EXPORT_SYMBOL_GPL(virtqueue_kick); |
| 600 | |
| 601 | static void detach_buf(struct vring_virtqueue *vq, unsigned int head) |
| 602 | { |
| 603 | unsigned int i, j; |
| 604 | u16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT); |
| 605 | |
| 606 | /* Clear data ptr. */ |
| 607 | vq->desc_state[head].data = NULL; |
| 608 | |
| 609 | /* Put back on free list: unmap first-level descriptors and find end */ |
| 610 | i = head; |
| 611 | |
| 612 | while (vq->vring.desc[i].flags & nextflag) { |
| 613 | vring_unmap_one(vq, &vq->vring.desc[i]); |
| 614 | i = virtio16_to_cpu(vq->vq.vdev, vq->vring.desc[i].next); |
| 615 | vq->vq.num_free++; |
| 616 | } |
| 617 | |
| 618 | vring_unmap_one(vq, &vq->vring.desc[i]); |
| 619 | vq->vring.desc[i].next = cpu_to_virtio16(vq->vq.vdev, vq->free_head); |
| 620 | vq->free_head = head; |
| 621 | |
| 622 | /* Plus final descriptor */ |
| 623 | vq->vq.num_free++; |
| 624 | |
| 625 | /* Free the indirect table, if any, now that it's unmapped. */ |
| 626 | if (vq->desc_state[head].indir_desc) { |
| 627 | struct vring_desc *indir_desc = vq->desc_state[head].indir_desc; |
| 628 | u32 len = virtio32_to_cpu(vq->vq.vdev, vq->vring.desc[head].len); |
| 629 | |
| 630 | BUG_ON(!(vq->vring.desc[head].flags & |
| 631 | cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT))); |
| 632 | BUG_ON(len == 0 || len % sizeof(struct vring_desc)); |
| 633 | |
| 634 | for (j = 0; j < len / sizeof(struct vring_desc); j++) |
| 635 | vring_unmap_one(vq, &indir_desc[j]); |
| 636 | |
| 637 | kfree(vq->desc_state[head].indir_desc); |
| 638 | vq->desc_state[head].indir_desc = NULL; |
| 639 | } |
| 640 | } |
| 641 | |
| 642 | static inline bool more_used(const struct vring_virtqueue *vq) |
| 643 | { |
| 644 | return vq->last_used_idx != virtio16_to_cpu(vq->vq.vdev, vq->vring.used->idx); |
| 645 | } |
| 646 | |
| 647 | /** |
| 648 | * virtqueue_get_buf - get the next used buffer |
| 649 | * @vq: the struct virtqueue we're talking about. |
| 650 | * @len: the length written into the buffer |
| 651 | * |
| 652 | * If the driver wrote data into the buffer, @len will be set to the |
| 653 | * amount written. This means you don't need to clear the buffer |
| 654 | * beforehand to ensure there's no data leakage in the case of short |
| 655 | * writes. |
| 656 | * |
| 657 | * Caller must ensure we don't call this with other virtqueue |
| 658 | * operations at the same time (except where noted). |
| 659 | * |
| 660 | * Returns NULL if there are no used buffers, or the "data" token |
| 661 | * handed to virtqueue_add_*(). |
| 662 | */ |
| 663 | void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len) |
| 664 | { |
| 665 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 666 | void *ret; |
| 667 | unsigned int i; |
| 668 | u16 last_used; |
| 669 | |
| 670 | START_USE(vq); |
| 671 | |
| 672 | if (unlikely(vq->broken)) { |
| 673 | END_USE(vq); |
| 674 | return NULL; |
| 675 | } |
| 676 | |
| 677 | if (!more_used(vq)) { |
| 678 | pr_debug("No more buffers in queue\n"); |
| 679 | END_USE(vq); |
| 680 | return NULL; |
| 681 | } |
| 682 | |
| 683 | /* Only get used array entries after they have been exposed by host. */ |
| 684 | virtio_rmb(vq->weak_barriers); |
| 685 | |
| 686 | last_used = (vq->last_used_idx & (vq->vring.num - 1)); |
| 687 | i = virtio32_to_cpu(_vq->vdev, vq->vring.used->ring[last_used].id); |
| 688 | *len = virtio32_to_cpu(_vq->vdev, vq->vring.used->ring[last_used].len); |
| 689 | |
| 690 | if (unlikely(i >= vq->vring.num)) { |
| 691 | BAD_RING(vq, "id %u out of range\n", i); |
| 692 | return NULL; |
| 693 | } |
| 694 | if (unlikely(!vq->desc_state[i].data)) { |
| 695 | BAD_RING(vq, "id %u is not a head!\n", i); |
| 696 | return NULL; |
| 697 | } |
| 698 | |
| 699 | /* detach_buf clears data, so grab it now. */ |
| 700 | ret = vq->desc_state[i].data; |
| 701 | detach_buf(vq, i); |
| 702 | vq->last_used_idx++; |
| 703 | /* If we expect an interrupt for the next entry, tell host |
| 704 | * by writing event index and flush out the write before |
| 705 | * the read in the next get_buf call. */ |
| 706 | if (!(vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) |
| 707 | virtio_store_mb(vq->weak_barriers, |
| 708 | &vring_used_event(&vq->vring), |
| 709 | cpu_to_virtio16(_vq->vdev, vq->last_used_idx)); |
| 710 | |
| 711 | #ifdef DEBUG |
| 712 | vq->last_add_time_valid = false; |
| 713 | #endif |
| 714 | |
| 715 | END_USE(vq); |
| 716 | return ret; |
| 717 | } |
| 718 | EXPORT_SYMBOL_GPL(virtqueue_get_buf); |
| 719 | |
| 720 | /** |
| 721 | * virtqueue_disable_cb - disable callbacks |
| 722 | * @vq: the struct virtqueue we're talking about. |
| 723 | * |
| 724 | * Note that this is not necessarily synchronous, hence unreliable and only |
| 725 | * useful as an optimization. |
| 726 | * |
| 727 | * Unlike other operations, this need not be serialized. |
| 728 | */ |
| 729 | void virtqueue_disable_cb(struct virtqueue *_vq) |
| 730 | { |
| 731 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 732 | |
| 733 | if (!(vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) { |
| 734 | vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT; |
| 735 | if (!vq->event) |
| 736 | vq->vring.avail->flags = cpu_to_virtio16(_vq->vdev, vq->avail_flags_shadow); |
| 737 | } |
| 738 | |
| 739 | } |
| 740 | EXPORT_SYMBOL_GPL(virtqueue_disable_cb); |
| 741 | |
| 742 | /** |
| 743 | * virtqueue_enable_cb_prepare - restart callbacks after disable_cb |
| 744 | * @vq: the struct virtqueue we're talking about. |
| 745 | * |
| 746 | * This re-enables callbacks; it returns current queue state |
| 747 | * in an opaque unsigned value. This value should be later tested by |
| 748 | * virtqueue_poll, to detect a possible race between the driver checking for |
| 749 | * more work, and enabling callbacks. |
| 750 | * |
| 751 | * Caller must ensure we don't call this with other virtqueue |
| 752 | * operations at the same time (except where noted). |
| 753 | */ |
| 754 | unsigned virtqueue_enable_cb_prepare(struct virtqueue *_vq) |
| 755 | { |
| 756 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 757 | u16 last_used_idx; |
| 758 | |
| 759 | START_USE(vq); |
| 760 | |
| 761 | /* We optimistically turn back on interrupts, then check if there was |
| 762 | * more to do. */ |
| 763 | /* Depending on the VIRTIO_RING_F_EVENT_IDX feature, we need to |
| 764 | * either clear the flags bit or point the event index at the next |
| 765 | * entry. Always do both to keep code simple. */ |
| 766 | if (vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT) { |
| 767 | vq->avail_flags_shadow &= ~VRING_AVAIL_F_NO_INTERRUPT; |
| 768 | if (!vq->event) |
| 769 | vq->vring.avail->flags = cpu_to_virtio16(_vq->vdev, vq->avail_flags_shadow); |
| 770 | } |
| 771 | vring_used_event(&vq->vring) = cpu_to_virtio16(_vq->vdev, last_used_idx = vq->last_used_idx); |
| 772 | END_USE(vq); |
| 773 | return last_used_idx; |
| 774 | } |
| 775 | EXPORT_SYMBOL_GPL(virtqueue_enable_cb_prepare); |
| 776 | |
| 777 | /** |
| 778 | * virtqueue_poll - query pending used buffers |
| 779 | * @vq: the struct virtqueue we're talking about. |
| 780 | * @last_used_idx: virtqueue state (from call to virtqueue_enable_cb_prepare). |
| 781 | * |
| 782 | * Returns "true" if there are pending used buffers in the queue. |
| 783 | * |
| 784 | * This does not need to be serialized. |
| 785 | */ |
| 786 | bool virtqueue_poll(struct virtqueue *_vq, unsigned last_used_idx) |
| 787 | { |
| 788 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 789 | |
| 790 | virtio_mb(vq->weak_barriers); |
| 791 | return (u16)last_used_idx != virtio16_to_cpu(_vq->vdev, vq->vring.used->idx); |
| 792 | } |
| 793 | EXPORT_SYMBOL_GPL(virtqueue_poll); |
| 794 | |
| 795 | /** |
| 796 | * virtqueue_enable_cb - restart callbacks after disable_cb. |
| 797 | * @vq: the struct virtqueue we're talking about. |
| 798 | * |
| 799 | * This re-enables callbacks; it returns "false" if there are pending |
| 800 | * buffers in the queue, to detect a possible race between the driver |
| 801 | * checking for more work, and enabling callbacks. |
| 802 | * |
| 803 | * Caller must ensure we don't call this with other virtqueue |
| 804 | * operations at the same time (except where noted). |
| 805 | */ |
| 806 | bool virtqueue_enable_cb(struct virtqueue *_vq) |
| 807 | { |
| 808 | unsigned last_used_idx = virtqueue_enable_cb_prepare(_vq); |
| 809 | return !virtqueue_poll(_vq, last_used_idx); |
| 810 | } |
| 811 | EXPORT_SYMBOL_GPL(virtqueue_enable_cb); |
| 812 | |
| 813 | /** |
| 814 | * virtqueue_enable_cb_delayed - restart callbacks after disable_cb. |
| 815 | * @vq: the struct virtqueue we're talking about. |
| 816 | * |
| 817 | * This re-enables callbacks but hints to the other side to delay |
| 818 | * interrupts until most of the available buffers have been processed; |
| 819 | * it returns "false" if there are many pending buffers in the queue, |
| 820 | * to detect a possible race between the driver checking for more work, |
| 821 | * and enabling callbacks. |
| 822 | * |
| 823 | * Caller must ensure we don't call this with other virtqueue |
| 824 | * operations at the same time (except where noted). |
| 825 | */ |
| 826 | bool virtqueue_enable_cb_delayed(struct virtqueue *_vq) |
| 827 | { |
| 828 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 829 | u16 bufs; |
| 830 | |
| 831 | START_USE(vq); |
| 832 | |
| 833 | /* We optimistically turn back on interrupts, then check if there was |
| 834 | * more to do. */ |
| 835 | /* Depending on the VIRTIO_RING_F_USED_EVENT_IDX feature, we need to |
| 836 | * either clear the flags bit or point the event index at the next |
| 837 | * entry. Always update the event index to keep code simple. */ |
| 838 | if (vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT) { |
| 839 | vq->avail_flags_shadow &= ~VRING_AVAIL_F_NO_INTERRUPT; |
| 840 | if (!vq->event) |
| 841 | vq->vring.avail->flags = cpu_to_virtio16(_vq->vdev, vq->avail_flags_shadow); |
| 842 | } |
| 843 | /* TODO: tune this threshold */ |
| 844 | bufs = (u16)(vq->avail_idx_shadow - vq->last_used_idx) * 3 / 4; |
| 845 | |
| 846 | virtio_store_mb(vq->weak_barriers, |
| 847 | &vring_used_event(&vq->vring), |
| 848 | cpu_to_virtio16(_vq->vdev, vq->last_used_idx + bufs)); |
| 849 | |
| 850 | if (unlikely((u16)(virtio16_to_cpu(_vq->vdev, vq->vring.used->idx) - vq->last_used_idx) > bufs)) { |
| 851 | END_USE(vq); |
| 852 | return false; |
| 853 | } |
| 854 | |
| 855 | END_USE(vq); |
| 856 | return true; |
| 857 | } |
| 858 | EXPORT_SYMBOL_GPL(virtqueue_enable_cb_delayed); |
| 859 | |
| 860 | /** |
| 861 | * virtqueue_detach_unused_buf - detach first unused buffer |
| 862 | * @vq: the struct virtqueue we're talking about. |
| 863 | * |
| 864 | * Returns NULL or the "data" token handed to virtqueue_add_*(). |
| 865 | * This is not valid on an active queue; it is useful only for device |
| 866 | * shutdown. |
| 867 | */ |
| 868 | void *virtqueue_detach_unused_buf(struct virtqueue *_vq) |
| 869 | { |
| 870 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 871 | unsigned int i; |
| 872 | void *buf; |
| 873 | |
| 874 | START_USE(vq); |
| 875 | |
| 876 | for (i = 0; i < vq->vring.num; i++) { |
| 877 | if (!vq->desc_state[i].data) |
| 878 | continue; |
| 879 | /* detach_buf clears data, so grab it now. */ |
| 880 | buf = vq->desc_state[i].data; |
| 881 | detach_buf(vq, i); |
| 882 | vq->avail_idx_shadow--; |
| 883 | vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev, vq->avail_idx_shadow); |
| 884 | END_USE(vq); |
| 885 | return buf; |
| 886 | } |
| 887 | /* That should have freed everything. */ |
| 888 | BUG_ON(vq->vq.num_free != vq->vring.num); |
| 889 | |
| 890 | END_USE(vq); |
| 891 | return NULL; |
| 892 | } |
| 893 | EXPORT_SYMBOL_GPL(virtqueue_detach_unused_buf); |
| 894 | |
| 895 | irqreturn_t vring_interrupt(int irq, void *_vq) |
| 896 | { |
| 897 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 898 | |
| 899 | if (!more_used(vq)) { |
| 900 | pr_debug("virtqueue interrupt with no work for %p\n", vq); |
| 901 | return IRQ_NONE; |
| 902 | } |
| 903 | |
| 904 | if (unlikely(vq->broken)) |
| 905 | return IRQ_HANDLED; |
| 906 | |
| 907 | pr_debug("virtqueue callback for %p (%p)\n", vq, vq->vq.callback); |
| 908 | if (vq->vq.callback) |
| 909 | vq->vq.callback(&vq->vq); |
| 910 | |
| 911 | return IRQ_HANDLED; |
| 912 | } |
| 913 | EXPORT_SYMBOL_GPL(vring_interrupt); |
| 914 | |
| 915 | struct virtqueue *__vring_new_virtqueue(unsigned int index, |
| 916 | struct vring vring, |
| 917 | struct virtio_device *vdev, |
| 918 | bool weak_barriers, |
| 919 | bool (*notify)(struct virtqueue *), |
| 920 | void (*callback)(struct virtqueue *), |
| 921 | const char *name) |
| 922 | { |
| 923 | unsigned int i; |
| 924 | struct vring_virtqueue *vq; |
| 925 | |
| 926 | vq = kmalloc(sizeof(*vq) + vring.num * sizeof(struct vring_desc_state), |
| 927 | GFP_KERNEL); |
| 928 | if (!vq) |
| 929 | return NULL; |
| 930 | |
| 931 | vq->vring = vring; |
| 932 | vq->vq.callback = callback; |
| 933 | vq->vq.vdev = vdev; |
| 934 | vq->vq.name = name; |
| 935 | vq->vq.num_free = vring.num; |
| 936 | vq->vq.index = index; |
| 937 | vq->we_own_ring = false; |
| 938 | vq->queue_dma_addr = 0; |
| 939 | vq->queue_size_in_bytes = 0; |
| 940 | vq->notify = notify; |
| 941 | vq->weak_barriers = weak_barriers; |
| 942 | vq->broken = false; |
| 943 | vq->last_used_idx = 0; |
| 944 | vq->avail_flags_shadow = 0; |
| 945 | vq->avail_idx_shadow = 0; |
| 946 | vq->num_added = 0; |
| 947 | list_add_tail(&vq->vq.list, &vdev->vqs); |
| 948 | #ifdef DEBUG |
| 949 | vq->in_use = false; |
| 950 | vq->last_add_time_valid = false; |
| 951 | #endif |
| 952 | |
| 953 | vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC); |
| 954 | vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); |
| 955 | |
| 956 | /* No callback? Tell other side not to bother us. */ |
| 957 | if (!callback) { |
| 958 | vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT; |
| 959 | if (!vq->event) |
| 960 | vq->vring.avail->flags = cpu_to_virtio16(vdev, vq->avail_flags_shadow); |
| 961 | } |
| 962 | |
| 963 | /* Put everything in free lists. */ |
| 964 | vq->free_head = 0; |
| 965 | for (i = 0; i < vring.num-1; i++) |
| 966 | vq->vring.desc[i].next = cpu_to_virtio16(vdev, i + 1); |
| 967 | memset(vq->desc_state, 0, vring.num * sizeof(struct vring_desc_state)); |
| 968 | |
| 969 | return &vq->vq; |
| 970 | } |
| 971 | EXPORT_SYMBOL_GPL(__vring_new_virtqueue); |
| 972 | |
| 973 | static void *vring_alloc_queue(struct virtio_device *vdev, size_t size, |
| 974 | dma_addr_t *dma_handle, gfp_t flag) |
| 975 | { |
| 976 | if (vring_use_dma_api(vdev)) { |
| 977 | return dma_alloc_coherent(vdev->dev.parent, size, |
| 978 | dma_handle, flag); |
| 979 | } else { |
| 980 | void *queue = alloc_pages_exact(PAGE_ALIGN(size), flag); |
| 981 | if (queue) { |
| 982 | phys_addr_t phys_addr = virt_to_phys(queue); |
| 983 | *dma_handle = (dma_addr_t)phys_addr; |
| 984 | |
| 985 | /* |
| 986 | * Sanity check: make sure we dind't truncate |
| 987 | * the address. The only arches I can find that |
| 988 | * have 64-bit phys_addr_t but 32-bit dma_addr_t |
| 989 | * are certain non-highmem MIPS and x86 |
| 990 | * configurations, but these configurations |
| 991 | * should never allocate physical pages above 32 |
| 992 | * bits, so this is fine. Just in case, throw a |
| 993 | * warning and abort if we end up with an |
| 994 | * unrepresentable address. |
| 995 | */ |
| 996 | if (WARN_ON_ONCE(*dma_handle != phys_addr)) { |
| 997 | free_pages_exact(queue, PAGE_ALIGN(size)); |
| 998 | return NULL; |
| 999 | } |
| 1000 | } |
| 1001 | return queue; |
| 1002 | } |
| 1003 | } |
| 1004 | |
| 1005 | static void vring_free_queue(struct virtio_device *vdev, size_t size, |
| 1006 | void *queue, dma_addr_t dma_handle) |
| 1007 | { |
| 1008 | if (vring_use_dma_api(vdev)) { |
| 1009 | dma_free_coherent(vdev->dev.parent, size, queue, dma_handle); |
| 1010 | } else { |
| 1011 | free_pages_exact(queue, PAGE_ALIGN(size)); |
| 1012 | } |
| 1013 | } |
| 1014 | |
| 1015 | struct virtqueue *vring_create_virtqueue( |
| 1016 | unsigned int index, |
| 1017 | unsigned int num, |
| 1018 | unsigned int vring_align, |
| 1019 | struct virtio_device *vdev, |
| 1020 | bool weak_barriers, |
| 1021 | bool may_reduce_num, |
| 1022 | bool (*notify)(struct virtqueue *), |
| 1023 | void (*callback)(struct virtqueue *), |
| 1024 | const char *name) |
| 1025 | { |
| 1026 | struct virtqueue *vq; |
| 1027 | void *queue = NULL; |
| 1028 | dma_addr_t dma_addr; |
| 1029 | size_t queue_size_in_bytes; |
| 1030 | struct vring vring; |
| 1031 | |
| 1032 | /* We assume num is a power of 2. */ |
| 1033 | if (num & (num - 1)) { |
| 1034 | dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num); |
| 1035 | return NULL; |
| 1036 | } |
| 1037 | |
| 1038 | /* TODO: allocate each queue chunk individually */ |
| 1039 | for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) { |
| 1040 | queue = vring_alloc_queue(vdev, vring_size(num, vring_align), |
| 1041 | &dma_addr, |
| 1042 | GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO); |
| 1043 | if (queue) |
| 1044 | break; |
| 1045 | } |
| 1046 | |
| 1047 | if (!num) |
| 1048 | return NULL; |
| 1049 | |
| 1050 | if (!queue) { |
| 1051 | /* Try to get a single page. You are my only hope! */ |
| 1052 | queue = vring_alloc_queue(vdev, vring_size(num, vring_align), |
| 1053 | &dma_addr, GFP_KERNEL|__GFP_ZERO); |
| 1054 | } |
| 1055 | if (!queue) |
| 1056 | return NULL; |
| 1057 | |
| 1058 | queue_size_in_bytes = vring_size(num, vring_align); |
| 1059 | vring_init(&vring, num, queue, vring_align); |
| 1060 | |
| 1061 | vq = __vring_new_virtqueue(index, vring, vdev, weak_barriers, |
| 1062 | notify, callback, name); |
| 1063 | if (!vq) { |
| 1064 | vring_free_queue(vdev, queue_size_in_bytes, queue, |
| 1065 | dma_addr); |
| 1066 | return NULL; |
| 1067 | } |
| 1068 | |
| 1069 | to_vvq(vq)->queue_dma_addr = dma_addr; |
| 1070 | to_vvq(vq)->queue_size_in_bytes = queue_size_in_bytes; |
| 1071 | to_vvq(vq)->we_own_ring = true; |
| 1072 | |
| 1073 | return vq; |
| 1074 | } |
| 1075 | EXPORT_SYMBOL_GPL(vring_create_virtqueue); |
| 1076 | |
| 1077 | struct virtqueue *vring_new_virtqueue(unsigned int index, |
| 1078 | unsigned int num, |
| 1079 | unsigned int vring_align, |
| 1080 | struct virtio_device *vdev, |
| 1081 | bool weak_barriers, |
| 1082 | void *pages, |
| 1083 | bool (*notify)(struct virtqueue *vq), |
| 1084 | void (*callback)(struct virtqueue *vq), |
| 1085 | const char *name) |
| 1086 | { |
| 1087 | struct vring vring; |
| 1088 | vring_init(&vring, num, pages, vring_align); |
| 1089 | return __vring_new_virtqueue(index, vring, vdev, weak_barriers, |
| 1090 | notify, callback, name); |
| 1091 | } |
| 1092 | EXPORT_SYMBOL_GPL(vring_new_virtqueue); |
| 1093 | |
| 1094 | void vring_del_virtqueue(struct virtqueue *_vq) |
| 1095 | { |
| 1096 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 1097 | |
| 1098 | if (vq->we_own_ring) { |
| 1099 | vring_free_queue(vq->vq.vdev, vq->queue_size_in_bytes, |
| 1100 | vq->vring.desc, vq->queue_dma_addr); |
| 1101 | } |
| 1102 | list_del(&_vq->list); |
| 1103 | kfree(vq); |
| 1104 | } |
| 1105 | EXPORT_SYMBOL_GPL(vring_del_virtqueue); |
| 1106 | |
| 1107 | /* Manipulates transport-specific feature bits. */ |
| 1108 | void vring_transport_features(struct virtio_device *vdev) |
| 1109 | { |
| 1110 | unsigned int i; |
| 1111 | |
| 1112 | for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) { |
| 1113 | switch (i) { |
| 1114 | case VIRTIO_RING_F_INDIRECT_DESC: |
| 1115 | break; |
| 1116 | case VIRTIO_RING_F_EVENT_IDX: |
| 1117 | break; |
| 1118 | case VIRTIO_F_VERSION_1: |
| 1119 | break; |
| 1120 | case VIRTIO_F_IOMMU_PLATFORM: |
| 1121 | break; |
| 1122 | default: |
| 1123 | /* We don't understand this bit. */ |
| 1124 | __virtio_clear_bit(vdev, i); |
| 1125 | } |
| 1126 | } |
| 1127 | } |
| 1128 | EXPORT_SYMBOL_GPL(vring_transport_features); |
| 1129 | |
| 1130 | /** |
| 1131 | * virtqueue_get_vring_size - return the size of the virtqueue's vring |
| 1132 | * @vq: the struct virtqueue containing the vring of interest. |
| 1133 | * |
| 1134 | * Returns the size of the vring. This is mainly used for boasting to |
| 1135 | * userspace. Unlike other operations, this need not be serialized. |
| 1136 | */ |
| 1137 | unsigned int virtqueue_get_vring_size(struct virtqueue *_vq) |
| 1138 | { |
| 1139 | |
| 1140 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 1141 | |
| 1142 | return vq->vring.num; |
| 1143 | } |
| 1144 | EXPORT_SYMBOL_GPL(virtqueue_get_vring_size); |
| 1145 | |
| 1146 | bool virtqueue_is_broken(struct virtqueue *_vq) |
| 1147 | { |
| 1148 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 1149 | |
| 1150 | return vq->broken; |
| 1151 | } |
| 1152 | EXPORT_SYMBOL_GPL(virtqueue_is_broken); |
| 1153 | |
| 1154 | /* |
| 1155 | * This should prevent the device from being used, allowing drivers to |
| 1156 | * recover. You may need to grab appropriate locks to flush. |
| 1157 | */ |
| 1158 | void virtio_break_device(struct virtio_device *dev) |
| 1159 | { |
| 1160 | struct virtqueue *_vq; |
| 1161 | |
| 1162 | list_for_each_entry(_vq, &dev->vqs, list) { |
| 1163 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 1164 | vq->broken = true; |
| 1165 | } |
| 1166 | } |
| 1167 | EXPORT_SYMBOL_GPL(virtio_break_device); |
| 1168 | |
| 1169 | dma_addr_t virtqueue_get_desc_addr(struct virtqueue *_vq) |
| 1170 | { |
| 1171 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 1172 | |
| 1173 | BUG_ON(!vq->we_own_ring); |
| 1174 | |
| 1175 | return vq->queue_dma_addr; |
| 1176 | } |
| 1177 | EXPORT_SYMBOL_GPL(virtqueue_get_desc_addr); |
| 1178 | |
| 1179 | dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq) |
| 1180 | { |
| 1181 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 1182 | |
| 1183 | BUG_ON(!vq->we_own_ring); |
| 1184 | |
| 1185 | return vq->queue_dma_addr + |
| 1186 | ((char *)vq->vring.avail - (char *)vq->vring.desc); |
| 1187 | } |
| 1188 | EXPORT_SYMBOL_GPL(virtqueue_get_avail_addr); |
| 1189 | |
| 1190 | dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq) |
| 1191 | { |
| 1192 | struct vring_virtqueue *vq = to_vvq(_vq); |
| 1193 | |
| 1194 | BUG_ON(!vq->we_own_ring); |
| 1195 | |
| 1196 | return vq->queue_dma_addr + |
| 1197 | ((char *)vq->vring.used - (char *)vq->vring.desc); |
| 1198 | } |
| 1199 | EXPORT_SYMBOL_GPL(virtqueue_get_used_addr); |
| 1200 | |
| 1201 | const struct vring *virtqueue_get_vring(struct virtqueue *vq) |
| 1202 | { |
| 1203 | return &to_vvq(vq)->vring; |
| 1204 | } |
| 1205 | EXPORT_SYMBOL_GPL(virtqueue_get_vring); |
| 1206 | |
| 1207 | MODULE_LICENSE("GPL"); |