1 /* 2 * VFIO PCI config space virtualization 3 * 4 * Copyright (C) 2012 Red Hat, Inc. All rights reserved. 5 * Author: Alex Williamson <alex.williamson@redhat.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * Derived from original vfio: 12 * Copyright 2010 Cisco Systems, Inc. All rights reserved. 13 * Author: Tom Lyon, pugs@cisco.com 14 */ 15 16 /* 17 * This code handles reading and writing of PCI configuration registers. 18 * This is hairy because we want to allow a lot of flexibility to the 19 * user driver, but cannot trust it with all of the config fields. 20 * Tables determine which fields can be read and written, as well as 21 * which fields are 'virtualized' - special actions and translations to 22 * make it appear to the user that he has control, when in fact things 23 * must be negotiated with the underlying OS. 24 */ 25 26 #include <linux/fs.h> 27 #include <linux/pci.h> 28 #include <linux/uaccess.h> 29 #include <linux/vfio.h> 30 #include <linux/slab.h> 31 32 #include "vfio_pci_private.h" 33 34 /* Fake capability ID for standard config space */ 35 #define PCI_CAP_ID_BASIC 0 36 37 #define is_bar(offset) \ 38 ((offset >= PCI_BASE_ADDRESS_0 && offset < PCI_BASE_ADDRESS_5 + 4) || \ 39 (offset >= PCI_ROM_ADDRESS && offset < PCI_ROM_ADDRESS + 4)) 40 41 /* 42 * Lengths of PCI Config Capabilities 43 * 0: Removed from the user visible capability list 44 * FF: Variable length 45 */ 46 static const u8 pci_cap_length[PCI_CAP_ID_MAX + 1] = { 47 [PCI_CAP_ID_BASIC] = PCI_STD_HEADER_SIZEOF, /* pci config header */ 48 [PCI_CAP_ID_PM] = PCI_PM_SIZEOF, 49 [PCI_CAP_ID_AGP] = PCI_AGP_SIZEOF, 50 [PCI_CAP_ID_VPD] = PCI_CAP_VPD_SIZEOF, 51 [PCI_CAP_ID_SLOTID] = 0, /* bridge - don't care */ 52 [PCI_CAP_ID_MSI] = 0xFF, /* 10, 14, 20, or 24 */ 53 [PCI_CAP_ID_CHSWP] = 0, /* cpci - not yet */ 54 [PCI_CAP_ID_PCIX] = 0xFF, /* 8 or 24 */ 55 [PCI_CAP_ID_HT] = 0xFF, /* hypertransport */ 56 [PCI_CAP_ID_VNDR] = 0xFF, /* variable */ 57 [PCI_CAP_ID_DBG] = 0, /* debug - don't care */ 58 [PCI_CAP_ID_CCRC] = 0, /* cpci - not yet */ 59 [PCI_CAP_ID_SHPC] = 0, /* hotswap - not yet */ 60 [PCI_CAP_ID_SSVID] = 0, /* bridge - don't care */ 61 [PCI_CAP_ID_AGP3] = 0, /* AGP8x - not yet */ 62 [PCI_CAP_ID_SECDEV] = 0, /* secure device not yet */ 63 [PCI_CAP_ID_EXP] = 0xFF, /* 20 or 44 */ 64 [PCI_CAP_ID_MSIX] = PCI_CAP_MSIX_SIZEOF, 65 [PCI_CAP_ID_SATA] = 0xFF, 66 [PCI_CAP_ID_AF] = PCI_CAP_AF_SIZEOF, 67 }; 68 69 /* 70 * Lengths of PCIe/PCI-X Extended Config Capabilities 71 * 0: Removed or masked from the user visible capability list 72 * FF: Variable length 73 */ 74 static const u16 pci_ext_cap_length[PCI_EXT_CAP_ID_MAX + 1] = { 75 [PCI_EXT_CAP_ID_ERR] = PCI_ERR_ROOT_COMMAND, 76 [PCI_EXT_CAP_ID_VC] = 0xFF, 77 [PCI_EXT_CAP_ID_DSN] = PCI_EXT_CAP_DSN_SIZEOF, 78 [PCI_EXT_CAP_ID_PWR] = PCI_EXT_CAP_PWR_SIZEOF, 79 [PCI_EXT_CAP_ID_RCLD] = 0, /* root only - don't care */ 80 [PCI_EXT_CAP_ID_RCILC] = 0, /* root only - don't care */ 81 [PCI_EXT_CAP_ID_RCEC] = 0, /* root only - don't care */ 82 [PCI_EXT_CAP_ID_MFVC] = 0xFF, 83 [PCI_EXT_CAP_ID_VC9] = 0xFF, /* same as CAP_ID_VC */ 84 [PCI_EXT_CAP_ID_RCRB] = 0, /* root only - don't care */ 85 [PCI_EXT_CAP_ID_VNDR] = 0xFF, 86 [PCI_EXT_CAP_ID_CAC] = 0, /* obsolete */ 87 [PCI_EXT_CAP_ID_ACS] = 0xFF, 88 [PCI_EXT_CAP_ID_ARI] = PCI_EXT_CAP_ARI_SIZEOF, 89 [PCI_EXT_CAP_ID_ATS] = PCI_EXT_CAP_ATS_SIZEOF, 90 [PCI_EXT_CAP_ID_SRIOV] = PCI_EXT_CAP_SRIOV_SIZEOF, 91 [PCI_EXT_CAP_ID_MRIOV] = 0, /* not yet */ 92 [PCI_EXT_CAP_ID_MCAST] = PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF, 93 [PCI_EXT_CAP_ID_PRI] = PCI_EXT_CAP_PRI_SIZEOF, 94 [PCI_EXT_CAP_ID_AMD_XXX] = 0, /* not yet */ 95 [PCI_EXT_CAP_ID_REBAR] = 0xFF, 96 [PCI_EXT_CAP_ID_DPA] = 0xFF, 97 [PCI_EXT_CAP_ID_TPH] = 0xFF, 98 [PCI_EXT_CAP_ID_LTR] = PCI_EXT_CAP_LTR_SIZEOF, 99 [PCI_EXT_CAP_ID_SECPCI] = 0, /* not yet */ 100 [PCI_EXT_CAP_ID_PMUX] = 0, /* not yet */ 101 [PCI_EXT_CAP_ID_PASID] = 0, /* not yet */ 102 }; 103 104 /* 105 * Read/Write Permission Bits - one bit for each bit in capability 106 * Any field can be read if it exists, but what is read depends on 107 * whether the field is 'virtualized', or just pass thru to the 108 * hardware. Any virtualized field is also virtualized for writes. 109 * Writes are only permitted if they have a 1 bit here. 110 */ 111 struct perm_bits { 112 u8 *virt; /* read/write virtual data, not hw */ 113 u8 *write; /* writeable bits */ 114 int (*readfn)(struct vfio_pci_device *vdev, int pos, int count, 115 struct perm_bits *perm, int offset, __le32 *val); 116 int (*writefn)(struct vfio_pci_device *vdev, int pos, int count, 117 struct perm_bits *perm, int offset, __le32 val); 118 }; 119 120 #define NO_VIRT 0 121 #define ALL_VIRT 0xFFFFFFFFU 122 #define NO_WRITE 0 123 #define ALL_WRITE 0xFFFFFFFFU 124 125 static int vfio_user_config_read(struct pci_dev *pdev, int offset, 126 __le32 *val, int count) 127 { 128 int ret = -EINVAL; 129 u32 tmp_val = 0; 130 131 switch (count) { 132 case 1: 133 { 134 u8 tmp; 135 ret = pci_user_read_config_byte(pdev, offset, &tmp); 136 tmp_val = tmp; 137 break; 138 } 139 case 2: 140 { 141 u16 tmp; 142 ret = pci_user_read_config_word(pdev, offset, &tmp); 143 tmp_val = tmp; 144 break; 145 } 146 case 4: 147 ret = pci_user_read_config_dword(pdev, offset, &tmp_val); 148 break; 149 } 150 151 *val = cpu_to_le32(tmp_val); 152 153 return ret; 154 } 155 156 static int vfio_user_config_write(struct pci_dev *pdev, int offset, 157 __le32 val, int count) 158 { 159 int ret = -EINVAL; 160 u32 tmp_val = le32_to_cpu(val); 161 162 switch (count) { 163 case 1: 164 ret = pci_user_write_config_byte(pdev, offset, tmp_val); 165 break; 166 case 2: 167 ret = pci_user_write_config_word(pdev, offset, tmp_val); 168 break; 169 case 4: 170 ret = pci_user_write_config_dword(pdev, offset, tmp_val); 171 break; 172 } 173 174 return ret; 175 } 176 177 static int vfio_default_config_read(struct vfio_pci_device *vdev, int pos, 178 int count, struct perm_bits *perm, 179 int offset, __le32 *val) 180 { 181 __le32 virt = 0; 182 183 memcpy(val, vdev->vconfig + pos, count); 184 185 memcpy(&virt, perm->virt + offset, count); 186 187 /* Any non-virtualized bits? */ 188 if (cpu_to_le32(~0U >> (32 - (count * 8))) != virt) { 189 struct pci_dev *pdev = vdev->pdev; 190 __le32 phys_val = 0; 191 int ret; 192 193 ret = vfio_user_config_read(pdev, pos, &phys_val, count); 194 if (ret) 195 return ret; 196 197 *val = (phys_val & ~virt) | (*val & virt); 198 } 199 200 return count; 201 } 202 203 static int vfio_default_config_write(struct vfio_pci_device *vdev, int pos, 204 int count, struct perm_bits *perm, 205 int offset, __le32 val) 206 { 207 __le32 virt = 0, write = 0; 208 209 memcpy(&write, perm->write + offset, count); 210 211 if (!write) 212 return count; /* drop, no writable bits */ 213 214 memcpy(&virt, perm->virt + offset, count); 215 216 /* Virtualized and writable bits go to vconfig */ 217 if (write & virt) { 218 __le32 virt_val = 0; 219 220 memcpy(&virt_val, vdev->vconfig + pos, count); 221 222 virt_val &= ~(write & virt); 223 virt_val |= (val & (write & virt)); 224 225 memcpy(vdev->vconfig + pos, &virt_val, count); 226 } 227 228 /* Non-virtualzed and writable bits go to hardware */ 229 if (write & ~virt) { 230 struct pci_dev *pdev = vdev->pdev; 231 __le32 phys_val = 0; 232 int ret; 233 234 ret = vfio_user_config_read(pdev, pos, &phys_val, count); 235 if (ret) 236 return ret; 237 238 phys_val &= ~(write & ~virt); 239 phys_val |= (val & (write & ~virt)); 240 241 ret = vfio_user_config_write(pdev, pos, phys_val, count); 242 if (ret) 243 return ret; 244 } 245 246 return count; 247 } 248 249 /* Allow direct read from hardware, except for capability next pointer */ 250 static int vfio_direct_config_read(struct vfio_pci_device *vdev, int pos, 251 int count, struct perm_bits *perm, 252 int offset, __le32 *val) 253 { 254 int ret; 255 256 ret = vfio_user_config_read(vdev->pdev, pos, val, count); 257 if (ret) 258 return ret; 259 260 if (pos >= PCI_CFG_SPACE_SIZE) { /* Extended cap header mangling */ 261 if (offset < 4) 262 memcpy(val, vdev->vconfig + pos, count); 263 } else if (pos >= PCI_STD_HEADER_SIZEOF) { /* Std cap mangling */ 264 if (offset == PCI_CAP_LIST_ID && count > 1) 265 memcpy(val, vdev->vconfig + pos, 266 min(PCI_CAP_FLAGS, count)); 267 else if (offset == PCI_CAP_LIST_NEXT) 268 memcpy(val, vdev->vconfig + pos, 1); 269 } 270 271 return count; 272 } 273 274 /* Raw access skips any kind of virtualization */ 275 static int vfio_raw_config_write(struct vfio_pci_device *vdev, int pos, 276 int count, struct perm_bits *perm, 277 int offset, __le32 val) 278 { 279 int ret; 280 281 ret = vfio_user_config_write(vdev->pdev, pos, val, count); 282 if (ret) 283 return ret; 284 285 return count; 286 } 287 288 static int vfio_raw_config_read(struct vfio_pci_device *vdev, int pos, 289 int count, struct perm_bits *perm, 290 int offset, __le32 *val) 291 { 292 int ret; 293 294 ret = vfio_user_config_read(vdev->pdev, pos, val, count); 295 if (ret) 296 return ret; 297 298 return count; 299 } 300 301 /* Virt access uses only virtualization */ 302 static int vfio_virt_config_write(struct vfio_pci_device *vdev, int pos, 303 int count, struct perm_bits *perm, 304 int offset, __le32 val) 305 { 306 memcpy(vdev->vconfig + pos, &val, count); 307 return count; 308 } 309 310 static int vfio_virt_config_read(struct vfio_pci_device *vdev, int pos, 311 int count, struct perm_bits *perm, 312 int offset, __le32 *val) 313 { 314 memcpy(val, vdev->vconfig + pos, count); 315 return count; 316 } 317 318 /* Default capability regions to read-only, no-virtualization */ 319 static struct perm_bits cap_perms[PCI_CAP_ID_MAX + 1] = { 320 [0 ... PCI_CAP_ID_MAX] = { .readfn = vfio_direct_config_read } 321 }; 322 static struct perm_bits ecap_perms[PCI_EXT_CAP_ID_MAX + 1] = { 323 [0 ... PCI_EXT_CAP_ID_MAX] = { .readfn = vfio_direct_config_read } 324 }; 325 /* 326 * Default unassigned regions to raw read-write access. Some devices 327 * require this to function as they hide registers between the gaps in 328 * config space (be2net). Like MMIO and I/O port registers, we have 329 * to trust the hardware isolation. 330 */ 331 static struct perm_bits unassigned_perms = { 332 .readfn = vfio_raw_config_read, 333 .writefn = vfio_raw_config_write 334 }; 335 336 static struct perm_bits virt_perms = { 337 .readfn = vfio_virt_config_read, 338 .writefn = vfio_virt_config_write 339 }; 340 341 static void free_perm_bits(struct perm_bits *perm) 342 { 343 kfree(perm->virt); 344 kfree(perm->write); 345 perm->virt = NULL; 346 perm->write = NULL; 347 } 348 349 static int alloc_perm_bits(struct perm_bits *perm, int size) 350 { 351 /* 352 * Round up all permission bits to the next dword, this lets us 353 * ignore whether a read/write exceeds the defined capability 354 * structure. We can do this because: 355 * - Standard config space is already dword aligned 356 * - Capabilities are all dword aligned (bits 0:1 of next reserved) 357 * - Express capabilities defined as dword aligned 358 */ 359 size = round_up(size, 4); 360 361 /* 362 * Zero state is 363 * - All Readable, None Writeable, None Virtualized 364 */ 365 perm->virt = kzalloc(size, GFP_KERNEL); 366 perm->write = kzalloc(size, GFP_KERNEL); 367 if (!perm->virt || !perm->write) { 368 free_perm_bits(perm); 369 return -ENOMEM; 370 } 371 372 perm->readfn = vfio_default_config_read; 373 perm->writefn = vfio_default_config_write; 374 375 return 0; 376 } 377 378 /* 379 * Helper functions for filling in permission tables 380 */ 381 static inline void p_setb(struct perm_bits *p, int off, u8 virt, u8 write) 382 { 383 p->virt[off] = virt; 384 p->write[off] = write; 385 } 386 387 /* Handle endian-ness - pci and tables are little-endian */ 388 static inline void p_setw(struct perm_bits *p, int off, u16 virt, u16 write) 389 { 390 *(__le16 *)(&p->virt[off]) = cpu_to_le16(virt); 391 *(__le16 *)(&p->write[off]) = cpu_to_le16(write); 392 } 393 394 /* Handle endian-ness - pci and tables are little-endian */ 395 static inline void p_setd(struct perm_bits *p, int off, u32 virt, u32 write) 396 { 397 *(__le32 *)(&p->virt[off]) = cpu_to_le32(virt); 398 *(__le32 *)(&p->write[off]) = cpu_to_le32(write); 399 } 400 401 /* 402 * Restore the *real* BARs after we detect a FLR or backdoor reset. 403 * (backdoor = some device specific technique that we didn't catch) 404 */ 405 static void vfio_bar_restore(struct vfio_pci_device *vdev) 406 { 407 struct pci_dev *pdev = vdev->pdev; 408 u32 *rbar = vdev->rbar; 409 u16 cmd; 410 int i; 411 412 if (pdev->is_virtfn) 413 return; 414 415 pr_info("%s: %s reset recovery - restoring bars\n", 416 __func__, dev_name(&pdev->dev)); 417 418 for (i = PCI_BASE_ADDRESS_0; i <= PCI_BASE_ADDRESS_5; i += 4, rbar++) 419 pci_user_write_config_dword(pdev, i, *rbar); 420 421 pci_user_write_config_dword(pdev, PCI_ROM_ADDRESS, *rbar); 422 423 if (vdev->nointx) { 424 pci_user_read_config_word(pdev, PCI_COMMAND, &cmd); 425 cmd |= PCI_COMMAND_INTX_DISABLE; 426 pci_user_write_config_word(pdev, PCI_COMMAND, cmd); 427 } 428 } 429 430 static __le32 vfio_generate_bar_flags(struct pci_dev *pdev, int bar) 431 { 432 unsigned long flags = pci_resource_flags(pdev, bar); 433 u32 val; 434 435 if (flags & IORESOURCE_IO) 436 return cpu_to_le32(PCI_BASE_ADDRESS_SPACE_IO); 437 438 val = PCI_BASE_ADDRESS_SPACE_MEMORY; 439 440 if (flags & IORESOURCE_PREFETCH) 441 val |= PCI_BASE_ADDRESS_MEM_PREFETCH; 442 443 if (flags & IORESOURCE_MEM_64) 444 val |= PCI_BASE_ADDRESS_MEM_TYPE_64; 445 446 return cpu_to_le32(val); 447 } 448 449 /* 450 * Pretend we're hardware and tweak the values of the *virtual* PCI BARs 451 * to reflect the hardware capabilities. This implements BAR sizing. 452 */ 453 static void vfio_bar_fixup(struct vfio_pci_device *vdev) 454 { 455 struct pci_dev *pdev = vdev->pdev; 456 int i; 457 __le32 *bar; 458 u64 mask; 459 460 bar = (__le32 *)&vdev->vconfig[PCI_BASE_ADDRESS_0]; 461 462 for (i = PCI_STD_RESOURCES; i <= PCI_STD_RESOURCE_END; i++, bar++) { 463 if (!pci_resource_start(pdev, i)) { 464 *bar = 0; /* Unmapped by host = unimplemented to user */ 465 continue; 466 } 467 468 mask = ~(pci_resource_len(pdev, i) - 1); 469 470 *bar &= cpu_to_le32((u32)mask); 471 *bar |= vfio_generate_bar_flags(pdev, i); 472 473 if (*bar & cpu_to_le32(PCI_BASE_ADDRESS_MEM_TYPE_64)) { 474 bar++; 475 *bar &= cpu_to_le32((u32)(mask >> 32)); 476 i++; 477 } 478 } 479 480 bar = (__le32 *)&vdev->vconfig[PCI_ROM_ADDRESS]; 481 482 /* 483 * NB. REGION_INFO will have reported zero size if we weren't able 484 * to read the ROM, but we still return the actual BAR size here if 485 * it exists (or the shadow ROM space). 486 */ 487 if (pci_resource_start(pdev, PCI_ROM_RESOURCE)) { 488 mask = ~(pci_resource_len(pdev, PCI_ROM_RESOURCE) - 1); 489 mask |= PCI_ROM_ADDRESS_ENABLE; 490 *bar &= cpu_to_le32((u32)mask); 491 } else if (pdev->resource[PCI_ROM_RESOURCE].flags & 492 IORESOURCE_ROM_SHADOW) { 493 mask = ~(0x20000 - 1); 494 mask |= PCI_ROM_ADDRESS_ENABLE; 495 *bar &= cpu_to_le32((u32)mask); 496 } else 497 *bar = 0; 498 499 vdev->bardirty = false; 500 } 501 502 static int vfio_basic_config_read(struct vfio_pci_device *vdev, int pos, 503 int count, struct perm_bits *perm, 504 int offset, __le32 *val) 505 { 506 if (is_bar(offset)) /* pos == offset for basic config */ 507 vfio_bar_fixup(vdev); 508 509 count = vfio_default_config_read(vdev, pos, count, perm, offset, val); 510 511 /* Mask in virtual memory enable for SR-IOV devices */ 512 if (offset == PCI_COMMAND && vdev->pdev->is_virtfn) { 513 u16 cmd = le16_to_cpu(*(__le16 *)&vdev->vconfig[PCI_COMMAND]); 514 u32 tmp_val = le32_to_cpu(*val); 515 516 tmp_val |= cmd & PCI_COMMAND_MEMORY; 517 *val = cpu_to_le32(tmp_val); 518 } 519 520 return count; 521 } 522 523 /* Test whether BARs match the value we think they should contain */ 524 static bool vfio_need_bar_restore(struct vfio_pci_device *vdev) 525 { 526 int i = 0, pos = PCI_BASE_ADDRESS_0, ret; 527 u32 bar; 528 529 for (; pos <= PCI_BASE_ADDRESS_5; i++, pos += 4) { 530 if (vdev->rbar[i]) { 531 ret = pci_user_read_config_dword(vdev->pdev, pos, &bar); 532 if (ret || vdev->rbar[i] != bar) 533 return true; 534 } 535 } 536 537 return false; 538 } 539 540 static int vfio_basic_config_write(struct vfio_pci_device *vdev, int pos, 541 int count, struct perm_bits *perm, 542 int offset, __le32 val) 543 { 544 struct pci_dev *pdev = vdev->pdev; 545 __le16 *virt_cmd; 546 u16 new_cmd = 0; 547 int ret; 548 549 virt_cmd = (__le16 *)&vdev->vconfig[PCI_COMMAND]; 550 551 if (offset == PCI_COMMAND) { 552 bool phys_mem, virt_mem, new_mem, phys_io, virt_io, new_io; 553 u16 phys_cmd; 554 555 ret = pci_user_read_config_word(pdev, PCI_COMMAND, &phys_cmd); 556 if (ret) 557 return ret; 558 559 new_cmd = le32_to_cpu(val); 560 561 phys_mem = !!(phys_cmd & PCI_COMMAND_MEMORY); 562 virt_mem = !!(le16_to_cpu(*virt_cmd) & PCI_COMMAND_MEMORY); 563 new_mem = !!(new_cmd & PCI_COMMAND_MEMORY); 564 565 phys_io = !!(phys_cmd & PCI_COMMAND_IO); 566 virt_io = !!(le16_to_cpu(*virt_cmd) & PCI_COMMAND_IO); 567 new_io = !!(new_cmd & PCI_COMMAND_IO); 568 569 /* 570 * If the user is writing mem/io enable (new_mem/io) and we 571 * think it's already enabled (virt_mem/io), but the hardware 572 * shows it disabled (phys_mem/io, then the device has 573 * undergone some kind of backdoor reset and needs to be 574 * restored before we allow it to enable the bars. 575 * SR-IOV devices will trigger this, but we catch them later 576 */ 577 if ((new_mem && virt_mem && !phys_mem) || 578 (new_io && virt_io && !phys_io) || 579 vfio_need_bar_restore(vdev)) 580 vfio_bar_restore(vdev); 581 } 582 583 count = vfio_default_config_write(vdev, pos, count, perm, offset, val); 584 if (count < 0) 585 return count; 586 587 /* 588 * Save current memory/io enable bits in vconfig to allow for 589 * the test above next time. 590 */ 591 if (offset == PCI_COMMAND) { 592 u16 mask = PCI_COMMAND_MEMORY | PCI_COMMAND_IO; 593 594 *virt_cmd &= cpu_to_le16(~mask); 595 *virt_cmd |= cpu_to_le16(new_cmd & mask); 596 } 597 598 /* Emulate INTx disable */ 599 if (offset >= PCI_COMMAND && offset <= PCI_COMMAND + 1) { 600 bool virt_intx_disable; 601 602 virt_intx_disable = !!(le16_to_cpu(*virt_cmd) & 603 PCI_COMMAND_INTX_DISABLE); 604 605 if (virt_intx_disable && !vdev->virq_disabled) { 606 vdev->virq_disabled = true; 607 vfio_pci_intx_mask(vdev); 608 } else if (!virt_intx_disable && vdev->virq_disabled) { 609 vdev->virq_disabled = false; 610 vfio_pci_intx_unmask(vdev); 611 } 612 } 613 614 if (is_bar(offset)) 615 vdev->bardirty = true; 616 617 return count; 618 } 619 620 /* Permissions for the Basic PCI Header */ 621 static int __init init_pci_cap_basic_perm(struct perm_bits *perm) 622 { 623 if (alloc_perm_bits(perm, PCI_STD_HEADER_SIZEOF)) 624 return -ENOMEM; 625 626 perm->readfn = vfio_basic_config_read; 627 perm->writefn = vfio_basic_config_write; 628 629 /* Virtualized for SR-IOV functions, which just have FFFF */ 630 p_setw(perm, PCI_VENDOR_ID, (u16)ALL_VIRT, NO_WRITE); 631 p_setw(perm, PCI_DEVICE_ID, (u16)ALL_VIRT, NO_WRITE); 632 633 /* 634 * Virtualize INTx disable, we use it internally for interrupt 635 * control and can emulate it for non-PCI 2.3 devices. 636 */ 637 p_setw(perm, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE, (u16)ALL_WRITE); 638 639 /* Virtualize capability list, we might want to skip/disable */ 640 p_setw(perm, PCI_STATUS, PCI_STATUS_CAP_LIST, NO_WRITE); 641 642 /* No harm to write */ 643 p_setb(perm, PCI_CACHE_LINE_SIZE, NO_VIRT, (u8)ALL_WRITE); 644 p_setb(perm, PCI_LATENCY_TIMER, NO_VIRT, (u8)ALL_WRITE); 645 p_setb(perm, PCI_BIST, NO_VIRT, (u8)ALL_WRITE); 646 647 /* Virtualize all bars, can't touch the real ones */ 648 p_setd(perm, PCI_BASE_ADDRESS_0, ALL_VIRT, ALL_WRITE); 649 p_setd(perm, PCI_BASE_ADDRESS_1, ALL_VIRT, ALL_WRITE); 650 p_setd(perm, PCI_BASE_ADDRESS_2, ALL_VIRT, ALL_WRITE); 651 p_setd(perm, PCI_BASE_ADDRESS_3, ALL_VIRT, ALL_WRITE); 652 p_setd(perm, PCI_BASE_ADDRESS_4, ALL_VIRT, ALL_WRITE); 653 p_setd(perm, PCI_BASE_ADDRESS_5, ALL_VIRT, ALL_WRITE); 654 p_setd(perm, PCI_ROM_ADDRESS, ALL_VIRT, ALL_WRITE); 655 656 /* Allow us to adjust capability chain */ 657 p_setb(perm, PCI_CAPABILITY_LIST, (u8)ALL_VIRT, NO_WRITE); 658 659 /* Sometimes used by sw, just virtualize */ 660 p_setb(perm, PCI_INTERRUPT_LINE, (u8)ALL_VIRT, (u8)ALL_WRITE); 661 662 /* Virtualize interrupt pin to allow hiding INTx */ 663 p_setb(perm, PCI_INTERRUPT_PIN, (u8)ALL_VIRT, (u8)NO_WRITE); 664 665 return 0; 666 } 667 668 static int vfio_pm_config_write(struct vfio_pci_device *vdev, int pos, 669 int count, struct perm_bits *perm, 670 int offset, __le32 val) 671 { 672 count = vfio_default_config_write(vdev, pos, count, perm, offset, val); 673 if (count < 0) 674 return count; 675 676 if (offset == PCI_PM_CTRL) { 677 pci_power_t state; 678 679 switch (le32_to_cpu(val) & PCI_PM_CTRL_STATE_MASK) { 680 case 0: 681 state = PCI_D0; 682 break; 683 case 1: 684 state = PCI_D1; 685 break; 686 case 2: 687 state = PCI_D2; 688 break; 689 case 3: 690 state = PCI_D3hot; 691 break; 692 } 693 694 pci_set_power_state(vdev->pdev, state); 695 } 696 697 return count; 698 } 699 700 /* Permissions for the Power Management capability */ 701 static int __init init_pci_cap_pm_perm(struct perm_bits *perm) 702 { 703 if (alloc_perm_bits(perm, pci_cap_length[PCI_CAP_ID_PM])) 704 return -ENOMEM; 705 706 perm->writefn = vfio_pm_config_write; 707 708 /* 709 * We always virtualize the next field so we can remove 710 * capabilities from the chain if we want to. 711 */ 712 p_setb(perm, PCI_CAP_LIST_NEXT, (u8)ALL_VIRT, NO_WRITE); 713 714 /* 715 * Power management is defined *per function*, so we can let 716 * the user change power state, but we trap and initiate the 717 * change ourselves, so the state bits are read-only. 718 */ 719 p_setd(perm, PCI_PM_CTRL, NO_VIRT, ~PCI_PM_CTRL_STATE_MASK); 720 return 0; 721 } 722 723 static int vfio_vpd_config_write(struct vfio_pci_device *vdev, int pos, 724 int count, struct perm_bits *perm, 725 int offset, __le32 val) 726 { 727 struct pci_dev *pdev = vdev->pdev; 728 __le16 *paddr = (__le16 *)(vdev->vconfig + pos - offset + PCI_VPD_ADDR); 729 __le32 *pdata = (__le32 *)(vdev->vconfig + pos - offset + PCI_VPD_DATA); 730 u16 addr; 731 u32 data; 732 733 /* 734 * Write through to emulation. If the write includes the upper byte 735 * of PCI_VPD_ADDR, then the PCI_VPD_ADDR_F bit is written and we 736 * have work to do. 737 */ 738 count = vfio_default_config_write(vdev, pos, count, perm, offset, val); 739 if (count < 0 || offset > PCI_VPD_ADDR + 1 || 740 offset + count <= PCI_VPD_ADDR + 1) 741 return count; 742 743 addr = le16_to_cpu(*paddr); 744 745 if (addr & PCI_VPD_ADDR_F) { 746 data = le32_to_cpu(*pdata); 747 if (pci_write_vpd(pdev, addr & ~PCI_VPD_ADDR_F, 4, &data) != 4) 748 return count; 749 } else { 750 data = 0; 751 if (pci_read_vpd(pdev, addr, 4, &data) < 0) 752 return count; 753 *pdata = cpu_to_le32(data); 754 } 755 756 /* 757 * Toggle PCI_VPD_ADDR_F in the emulated PCI_VPD_ADDR register to 758 * signal completion. If an error occurs above, we assume that not 759 * toggling this bit will induce a driver timeout. 760 */ 761 addr ^= PCI_VPD_ADDR_F; 762 *paddr = cpu_to_le16(addr); 763 764 return count; 765 } 766 767 /* Permissions for Vital Product Data capability */ 768 static int __init init_pci_cap_vpd_perm(struct perm_bits *perm) 769 { 770 if (alloc_perm_bits(perm, pci_cap_length[PCI_CAP_ID_VPD])) 771 return -ENOMEM; 772 773 perm->writefn = vfio_vpd_config_write; 774 775 /* 776 * We always virtualize the next field so we can remove 777 * capabilities from the chain if we want to. 778 */ 779 p_setb(perm, PCI_CAP_LIST_NEXT, (u8)ALL_VIRT, NO_WRITE); 780 781 /* 782 * Both the address and data registers are virtualized to 783 * enable access through the pci_vpd_read/write functions 784 */ 785 p_setw(perm, PCI_VPD_ADDR, (u16)ALL_VIRT, (u16)ALL_WRITE); 786 p_setd(perm, PCI_VPD_DATA, ALL_VIRT, ALL_WRITE); 787 788 return 0; 789 } 790 791 /* Permissions for PCI-X capability */ 792 static int __init init_pci_cap_pcix_perm(struct perm_bits *perm) 793 { 794 /* Alloc 24, but only 8 are used in v0 */ 795 if (alloc_perm_bits(perm, PCI_CAP_PCIX_SIZEOF_V2)) 796 return -ENOMEM; 797 798 p_setb(perm, PCI_CAP_LIST_NEXT, (u8)ALL_VIRT, NO_WRITE); 799 800 p_setw(perm, PCI_X_CMD, NO_VIRT, (u16)ALL_WRITE); 801 p_setd(perm, PCI_X_ECC_CSR, NO_VIRT, ALL_WRITE); 802 return 0; 803 } 804 805 static int vfio_exp_config_write(struct vfio_pci_device *vdev, int pos, 806 int count, struct perm_bits *perm, 807 int offset, __le32 val) 808 { 809 __le16 *ctrl = (__le16 *)(vdev->vconfig + pos - 810 offset + PCI_EXP_DEVCTL); 811 812 count = vfio_default_config_write(vdev, pos, count, perm, offset, val); 813 if (count < 0) 814 return count; 815 816 /* 817 * The FLR bit is virtualized, if set and the device supports PCIe 818 * FLR, issue a reset_function. Regardless, clear the bit, the spec 819 * requires it to be always read as zero. NB, reset_function might 820 * not use a PCIe FLR, we don't have that level of granularity. 821 */ 822 if (*ctrl & cpu_to_le16(PCI_EXP_DEVCTL_BCR_FLR)) { 823 u32 cap; 824 int ret; 825 826 *ctrl &= ~cpu_to_le16(PCI_EXP_DEVCTL_BCR_FLR); 827 828 ret = pci_user_read_config_dword(vdev->pdev, 829 pos - offset + PCI_EXP_DEVCAP, 830 &cap); 831 832 if (!ret && (cap & PCI_EXP_DEVCAP_FLR)) 833 pci_try_reset_function(vdev->pdev); 834 } 835 836 return count; 837 } 838 839 /* Permissions for PCI Express capability */ 840 static int __init init_pci_cap_exp_perm(struct perm_bits *perm) 841 { 842 /* Alloc larger of two possible sizes */ 843 if (alloc_perm_bits(perm, PCI_CAP_EXP_ENDPOINT_SIZEOF_V2)) 844 return -ENOMEM; 845 846 perm->writefn = vfio_exp_config_write; 847 848 p_setb(perm, PCI_CAP_LIST_NEXT, (u8)ALL_VIRT, NO_WRITE); 849 850 /* 851 * Allow writes to device control fields, except devctl_phantom, 852 * which could confuse IOMMU, and the ARI bit in devctl2, which 853 * is set at probe time. FLR gets virtualized via our writefn. 854 */ 855 p_setw(perm, PCI_EXP_DEVCTL, 856 PCI_EXP_DEVCTL_BCR_FLR, ~PCI_EXP_DEVCTL_PHANTOM); 857 p_setw(perm, PCI_EXP_DEVCTL2, NO_VIRT, ~PCI_EXP_DEVCTL2_ARI); 858 return 0; 859 } 860 861 static int vfio_af_config_write(struct vfio_pci_device *vdev, int pos, 862 int count, struct perm_bits *perm, 863 int offset, __le32 val) 864 { 865 u8 *ctrl = vdev->vconfig + pos - offset + PCI_AF_CTRL; 866 867 count = vfio_default_config_write(vdev, pos, count, perm, offset, val); 868 if (count < 0) 869 return count; 870 871 /* 872 * The FLR bit is virtualized, if set and the device supports AF 873 * FLR, issue a reset_function. Regardless, clear the bit, the spec 874 * requires it to be always read as zero. NB, reset_function might 875 * not use an AF FLR, we don't have that level of granularity. 876 */ 877 if (*ctrl & PCI_AF_CTRL_FLR) { 878 u8 cap; 879 int ret; 880 881 *ctrl &= ~PCI_AF_CTRL_FLR; 882 883 ret = pci_user_read_config_byte(vdev->pdev, 884 pos - offset + PCI_AF_CAP, 885 &cap); 886 887 if (!ret && (cap & PCI_AF_CAP_FLR) && (cap & PCI_AF_CAP_TP)) 888 pci_try_reset_function(vdev->pdev); 889 } 890 891 return count; 892 } 893 894 /* Permissions for Advanced Function capability */ 895 static int __init init_pci_cap_af_perm(struct perm_bits *perm) 896 { 897 if (alloc_perm_bits(perm, pci_cap_length[PCI_CAP_ID_AF])) 898 return -ENOMEM; 899 900 perm->writefn = vfio_af_config_write; 901 902 p_setb(perm, PCI_CAP_LIST_NEXT, (u8)ALL_VIRT, NO_WRITE); 903 p_setb(perm, PCI_AF_CTRL, PCI_AF_CTRL_FLR, PCI_AF_CTRL_FLR); 904 return 0; 905 } 906 907 /* Permissions for Advanced Error Reporting extended capability */ 908 static int __init init_pci_ext_cap_err_perm(struct perm_bits *perm) 909 { 910 u32 mask; 911 912 if (alloc_perm_bits(perm, pci_ext_cap_length[PCI_EXT_CAP_ID_ERR])) 913 return -ENOMEM; 914 915 /* 916 * Virtualize the first dword of all express capabilities 917 * because it includes the next pointer. This lets us later 918 * remove capabilities from the chain if we need to. 919 */ 920 p_setd(perm, 0, ALL_VIRT, NO_WRITE); 921 922 /* Writable bits mask */ 923 mask = PCI_ERR_UNC_UND | /* Undefined */ 924 PCI_ERR_UNC_DLP | /* Data Link Protocol */ 925 PCI_ERR_UNC_SURPDN | /* Surprise Down */ 926 PCI_ERR_UNC_POISON_TLP | /* Poisoned TLP */ 927 PCI_ERR_UNC_FCP | /* Flow Control Protocol */ 928 PCI_ERR_UNC_COMP_TIME | /* Completion Timeout */ 929 PCI_ERR_UNC_COMP_ABORT | /* Completer Abort */ 930 PCI_ERR_UNC_UNX_COMP | /* Unexpected Completion */ 931 PCI_ERR_UNC_RX_OVER | /* Receiver Overflow */ 932 PCI_ERR_UNC_MALF_TLP | /* Malformed TLP */ 933 PCI_ERR_UNC_ECRC | /* ECRC Error Status */ 934 PCI_ERR_UNC_UNSUP | /* Unsupported Request */ 935 PCI_ERR_UNC_ACSV | /* ACS Violation */ 936 PCI_ERR_UNC_INTN | /* internal error */ 937 PCI_ERR_UNC_MCBTLP | /* MC blocked TLP */ 938 PCI_ERR_UNC_ATOMEG | /* Atomic egress blocked */ 939 PCI_ERR_UNC_TLPPRE; /* TLP prefix blocked */ 940 p_setd(perm, PCI_ERR_UNCOR_STATUS, NO_VIRT, mask); 941 p_setd(perm, PCI_ERR_UNCOR_MASK, NO_VIRT, mask); 942 p_setd(perm, PCI_ERR_UNCOR_SEVER, NO_VIRT, mask); 943 944 mask = PCI_ERR_COR_RCVR | /* Receiver Error Status */ 945 PCI_ERR_COR_BAD_TLP | /* Bad TLP Status */ 946 PCI_ERR_COR_BAD_DLLP | /* Bad DLLP Status */ 947 PCI_ERR_COR_REP_ROLL | /* REPLAY_NUM Rollover */ 948 PCI_ERR_COR_REP_TIMER | /* Replay Timer Timeout */ 949 PCI_ERR_COR_ADV_NFAT | /* Advisory Non-Fatal */ 950 PCI_ERR_COR_INTERNAL | /* Corrected Internal */ 951 PCI_ERR_COR_LOG_OVER; /* Header Log Overflow */ 952 p_setd(perm, PCI_ERR_COR_STATUS, NO_VIRT, mask); 953 p_setd(perm, PCI_ERR_COR_MASK, NO_VIRT, mask); 954 955 mask = PCI_ERR_CAP_ECRC_GENE | /* ECRC Generation Enable */ 956 PCI_ERR_CAP_ECRC_CHKE; /* ECRC Check Enable */ 957 p_setd(perm, PCI_ERR_CAP, NO_VIRT, mask); 958 return 0; 959 } 960 961 /* Permissions for Power Budgeting extended capability */ 962 static int __init init_pci_ext_cap_pwr_perm(struct perm_bits *perm) 963 { 964 if (alloc_perm_bits(perm, pci_ext_cap_length[PCI_EXT_CAP_ID_PWR])) 965 return -ENOMEM; 966 967 p_setd(perm, 0, ALL_VIRT, NO_WRITE); 968 969 /* Writing the data selector is OK, the info is still read-only */ 970 p_setb(perm, PCI_PWR_DATA, NO_VIRT, (u8)ALL_WRITE); 971 return 0; 972 } 973 974 /* 975 * Initialize the shared permission tables 976 */ 977 void vfio_pci_uninit_perm_bits(void) 978 { 979 free_perm_bits(&cap_perms[PCI_CAP_ID_BASIC]); 980 981 free_perm_bits(&cap_perms[PCI_CAP_ID_PM]); 982 free_perm_bits(&cap_perms[PCI_CAP_ID_VPD]); 983 free_perm_bits(&cap_perms[PCI_CAP_ID_PCIX]); 984 free_perm_bits(&cap_perms[PCI_CAP_ID_EXP]); 985 free_perm_bits(&cap_perms[PCI_CAP_ID_AF]); 986 987 free_perm_bits(&ecap_perms[PCI_EXT_CAP_ID_ERR]); 988 free_perm_bits(&ecap_perms[PCI_EXT_CAP_ID_PWR]); 989 } 990 991 int __init vfio_pci_init_perm_bits(void) 992 { 993 int ret; 994 995 /* Basic config space */ 996 ret = init_pci_cap_basic_perm(&cap_perms[PCI_CAP_ID_BASIC]); 997 998 /* Capabilities */ 999 ret |= init_pci_cap_pm_perm(&cap_perms[PCI_CAP_ID_PM]); 1000 ret |= init_pci_cap_vpd_perm(&cap_perms[PCI_CAP_ID_VPD]); 1001 ret |= init_pci_cap_pcix_perm(&cap_perms[PCI_CAP_ID_PCIX]); 1002 cap_perms[PCI_CAP_ID_VNDR].writefn = vfio_raw_config_write; 1003 ret |= init_pci_cap_exp_perm(&cap_perms[PCI_CAP_ID_EXP]); 1004 ret |= init_pci_cap_af_perm(&cap_perms[PCI_CAP_ID_AF]); 1005 1006 /* Extended capabilities */ 1007 ret |= init_pci_ext_cap_err_perm(&ecap_perms[PCI_EXT_CAP_ID_ERR]); 1008 ret |= init_pci_ext_cap_pwr_perm(&ecap_perms[PCI_EXT_CAP_ID_PWR]); 1009 ecap_perms[PCI_EXT_CAP_ID_VNDR].writefn = vfio_raw_config_write; 1010 1011 if (ret) 1012 vfio_pci_uninit_perm_bits(); 1013 1014 return ret; 1015 } 1016 1017 static int vfio_find_cap_start(struct vfio_pci_device *vdev, int pos) 1018 { 1019 u8 cap; 1020 int base = (pos >= PCI_CFG_SPACE_SIZE) ? PCI_CFG_SPACE_SIZE : 1021 PCI_STD_HEADER_SIZEOF; 1022 cap = vdev->pci_config_map[pos]; 1023 1024 if (cap == PCI_CAP_ID_BASIC) 1025 return 0; 1026 1027 /* XXX Can we have to abutting capabilities of the same type? */ 1028 while (pos - 1 >= base && vdev->pci_config_map[pos - 1] == cap) 1029 pos--; 1030 1031 return pos; 1032 } 1033 1034 static int vfio_msi_config_read(struct vfio_pci_device *vdev, int pos, 1035 int count, struct perm_bits *perm, 1036 int offset, __le32 *val) 1037 { 1038 /* Update max available queue size from msi_qmax */ 1039 if (offset <= PCI_MSI_FLAGS && offset + count >= PCI_MSI_FLAGS) { 1040 __le16 *flags; 1041 int start; 1042 1043 start = vfio_find_cap_start(vdev, pos); 1044 1045 flags = (__le16 *)&vdev->vconfig[start]; 1046 1047 *flags &= cpu_to_le16(~PCI_MSI_FLAGS_QMASK); 1048 *flags |= cpu_to_le16(vdev->msi_qmax << 1); 1049 } 1050 1051 return vfio_default_config_read(vdev, pos, count, perm, offset, val); 1052 } 1053 1054 static int vfio_msi_config_write(struct vfio_pci_device *vdev, int pos, 1055 int count, struct perm_bits *perm, 1056 int offset, __le32 val) 1057 { 1058 count = vfio_default_config_write(vdev, pos, count, perm, offset, val); 1059 if (count < 0) 1060 return count; 1061 1062 /* Fixup and write configured queue size and enable to hardware */ 1063 if (offset <= PCI_MSI_FLAGS && offset + count >= PCI_MSI_FLAGS) { 1064 __le16 *pflags; 1065 u16 flags; 1066 int start, ret; 1067 1068 start = vfio_find_cap_start(vdev, pos); 1069 1070 pflags = (__le16 *)&vdev->vconfig[start + PCI_MSI_FLAGS]; 1071 1072 flags = le16_to_cpu(*pflags); 1073 1074 /* MSI is enabled via ioctl */ 1075 if (!is_msi(vdev)) 1076 flags &= ~PCI_MSI_FLAGS_ENABLE; 1077 1078 /* Check queue size */ 1079 if ((flags & PCI_MSI_FLAGS_QSIZE) >> 4 > vdev->msi_qmax) { 1080 flags &= ~PCI_MSI_FLAGS_QSIZE; 1081 flags |= vdev->msi_qmax << 4; 1082 } 1083 1084 /* Write back to virt and to hardware */ 1085 *pflags = cpu_to_le16(flags); 1086 ret = pci_user_write_config_word(vdev->pdev, 1087 start + PCI_MSI_FLAGS, 1088 flags); 1089 if (ret) 1090 return ret; 1091 } 1092 1093 return count; 1094 } 1095 1096 /* 1097 * MSI determination is per-device, so this routine gets used beyond 1098 * initialization time. Don't add __init 1099 */ 1100 static int init_pci_cap_msi_perm(struct perm_bits *perm, int len, u16 flags) 1101 { 1102 if (alloc_perm_bits(perm, len)) 1103 return -ENOMEM; 1104 1105 perm->readfn = vfio_msi_config_read; 1106 perm->writefn = vfio_msi_config_write; 1107 1108 p_setb(perm, PCI_CAP_LIST_NEXT, (u8)ALL_VIRT, NO_WRITE); 1109 1110 /* 1111 * The upper byte of the control register is reserved, 1112 * just setup the lower byte. 1113 */ 1114 p_setb(perm, PCI_MSI_FLAGS, (u8)ALL_VIRT, (u8)ALL_WRITE); 1115 p_setd(perm, PCI_MSI_ADDRESS_LO, ALL_VIRT, ALL_WRITE); 1116 if (flags & PCI_MSI_FLAGS_64BIT) { 1117 p_setd(perm, PCI_MSI_ADDRESS_HI, ALL_VIRT, ALL_WRITE); 1118 p_setw(perm, PCI_MSI_DATA_64, (u16)ALL_VIRT, (u16)ALL_WRITE); 1119 if (flags & PCI_MSI_FLAGS_MASKBIT) { 1120 p_setd(perm, PCI_MSI_MASK_64, NO_VIRT, ALL_WRITE); 1121 p_setd(perm, PCI_MSI_PENDING_64, NO_VIRT, ALL_WRITE); 1122 } 1123 } else { 1124 p_setw(perm, PCI_MSI_DATA_32, (u16)ALL_VIRT, (u16)ALL_WRITE); 1125 if (flags & PCI_MSI_FLAGS_MASKBIT) { 1126 p_setd(perm, PCI_MSI_MASK_32, NO_VIRT, ALL_WRITE); 1127 p_setd(perm, PCI_MSI_PENDING_32, NO_VIRT, ALL_WRITE); 1128 } 1129 } 1130 return 0; 1131 } 1132 1133 /* Determine MSI CAP field length; initialize msi_perms on 1st call per vdev */ 1134 static int vfio_msi_cap_len(struct vfio_pci_device *vdev, u8 pos) 1135 { 1136 struct pci_dev *pdev = vdev->pdev; 1137 int len, ret; 1138 u16 flags; 1139 1140 ret = pci_read_config_word(pdev, pos + PCI_MSI_FLAGS, &flags); 1141 if (ret) 1142 return pcibios_err_to_errno(ret); 1143 1144 len = 10; /* Minimum size */ 1145 if (flags & PCI_MSI_FLAGS_64BIT) 1146 len += 4; 1147 if (flags & PCI_MSI_FLAGS_MASKBIT) 1148 len += 10; 1149 1150 if (vdev->msi_perm) 1151 return len; 1152 1153 vdev->msi_perm = kmalloc(sizeof(struct perm_bits), GFP_KERNEL); 1154 if (!vdev->msi_perm) 1155 return -ENOMEM; 1156 1157 ret = init_pci_cap_msi_perm(vdev->msi_perm, len, flags); 1158 if (ret) 1159 return ret; 1160 1161 return len; 1162 } 1163 1164 /* Determine extended capability length for VC (2 & 9) and MFVC */ 1165 static int vfio_vc_cap_len(struct vfio_pci_device *vdev, u16 pos) 1166 { 1167 struct pci_dev *pdev = vdev->pdev; 1168 u32 tmp; 1169 int ret, evcc, phases, vc_arb; 1170 int len = PCI_CAP_VC_BASE_SIZEOF; 1171 1172 ret = pci_read_config_dword(pdev, pos + PCI_VC_PORT_CAP1, &tmp); 1173 if (ret) 1174 return pcibios_err_to_errno(ret); 1175 1176 evcc = tmp & PCI_VC_CAP1_EVCC; /* extended vc count */ 1177 ret = pci_read_config_dword(pdev, pos + PCI_VC_PORT_CAP2, &tmp); 1178 if (ret) 1179 return pcibios_err_to_errno(ret); 1180 1181 if (tmp & PCI_VC_CAP2_128_PHASE) 1182 phases = 128; 1183 else if (tmp & PCI_VC_CAP2_64_PHASE) 1184 phases = 64; 1185 else if (tmp & PCI_VC_CAP2_32_PHASE) 1186 phases = 32; 1187 else 1188 phases = 0; 1189 1190 vc_arb = phases * 4; 1191 1192 /* 1193 * Port arbitration tables are root & switch only; 1194 * function arbitration tables are function 0 only. 1195 * In either case, we'll never let user write them so 1196 * we don't care how big they are 1197 */ 1198 len += (1 + evcc) * PCI_CAP_VC_PER_VC_SIZEOF; 1199 if (vc_arb) { 1200 len = round_up(len, 16); 1201 len += vc_arb / 8; 1202 } 1203 return len; 1204 } 1205 1206 static int vfio_cap_len(struct vfio_pci_device *vdev, u8 cap, u8 pos) 1207 { 1208 struct pci_dev *pdev = vdev->pdev; 1209 u32 dword; 1210 u16 word; 1211 u8 byte; 1212 int ret; 1213 1214 switch (cap) { 1215 case PCI_CAP_ID_MSI: 1216 return vfio_msi_cap_len(vdev, pos); 1217 case PCI_CAP_ID_PCIX: 1218 ret = pci_read_config_word(pdev, pos + PCI_X_CMD, &word); 1219 if (ret) 1220 return pcibios_err_to_errno(ret); 1221 1222 if (PCI_X_CMD_VERSION(word)) { 1223 if (pdev->cfg_size > PCI_CFG_SPACE_SIZE) { 1224 /* Test for extended capabilities */ 1225 pci_read_config_dword(pdev, PCI_CFG_SPACE_SIZE, 1226 &dword); 1227 vdev->extended_caps = (dword != 0); 1228 } 1229 return PCI_CAP_PCIX_SIZEOF_V2; 1230 } else 1231 return PCI_CAP_PCIX_SIZEOF_V0; 1232 case PCI_CAP_ID_VNDR: 1233 /* length follows next field */ 1234 ret = pci_read_config_byte(pdev, pos + PCI_CAP_FLAGS, &byte); 1235 if (ret) 1236 return pcibios_err_to_errno(ret); 1237 1238 return byte; 1239 case PCI_CAP_ID_EXP: 1240 if (pdev->cfg_size > PCI_CFG_SPACE_SIZE) { 1241 /* Test for extended capabilities */ 1242 pci_read_config_dword(pdev, PCI_CFG_SPACE_SIZE, &dword); 1243 vdev->extended_caps = (dword != 0); 1244 } 1245 1246 /* length based on version */ 1247 if ((pcie_caps_reg(pdev) & PCI_EXP_FLAGS_VERS) == 1) 1248 return PCI_CAP_EXP_ENDPOINT_SIZEOF_V1; 1249 else 1250 return PCI_CAP_EXP_ENDPOINT_SIZEOF_V2; 1251 case PCI_CAP_ID_HT: 1252 ret = pci_read_config_byte(pdev, pos + 3, &byte); 1253 if (ret) 1254 return pcibios_err_to_errno(ret); 1255 1256 return (byte & HT_3BIT_CAP_MASK) ? 1257 HT_CAP_SIZEOF_SHORT : HT_CAP_SIZEOF_LONG; 1258 case PCI_CAP_ID_SATA: 1259 ret = pci_read_config_byte(pdev, pos + PCI_SATA_REGS, &byte); 1260 if (ret) 1261 return pcibios_err_to_errno(ret); 1262 1263 byte &= PCI_SATA_REGS_MASK; 1264 if (byte == PCI_SATA_REGS_INLINE) 1265 return PCI_SATA_SIZEOF_LONG; 1266 else 1267 return PCI_SATA_SIZEOF_SHORT; 1268 default: 1269 pr_warn("%s: %s unknown length for pci cap 0x%x@0x%x\n", 1270 dev_name(&pdev->dev), __func__, cap, pos); 1271 } 1272 1273 return 0; 1274 } 1275 1276 static int vfio_ext_cap_len(struct vfio_pci_device *vdev, u16 ecap, u16 epos) 1277 { 1278 struct pci_dev *pdev = vdev->pdev; 1279 u8 byte; 1280 u32 dword; 1281 int ret; 1282 1283 switch (ecap) { 1284 case PCI_EXT_CAP_ID_VNDR: 1285 ret = pci_read_config_dword(pdev, epos + PCI_VSEC_HDR, &dword); 1286 if (ret) 1287 return pcibios_err_to_errno(ret); 1288 1289 return dword >> PCI_VSEC_HDR_LEN_SHIFT; 1290 case PCI_EXT_CAP_ID_VC: 1291 case PCI_EXT_CAP_ID_VC9: 1292 case PCI_EXT_CAP_ID_MFVC: 1293 return vfio_vc_cap_len(vdev, epos); 1294 case PCI_EXT_CAP_ID_ACS: 1295 ret = pci_read_config_byte(pdev, epos + PCI_ACS_CAP, &byte); 1296 if (ret) 1297 return pcibios_err_to_errno(ret); 1298 1299 if (byte & PCI_ACS_EC) { 1300 int bits; 1301 1302 ret = pci_read_config_byte(pdev, 1303 epos + PCI_ACS_EGRESS_BITS, 1304 &byte); 1305 if (ret) 1306 return pcibios_err_to_errno(ret); 1307 1308 bits = byte ? round_up(byte, 32) : 256; 1309 return 8 + (bits / 8); 1310 } 1311 return 8; 1312 1313 case PCI_EXT_CAP_ID_REBAR: 1314 ret = pci_read_config_byte(pdev, epos + PCI_REBAR_CTRL, &byte); 1315 if (ret) 1316 return pcibios_err_to_errno(ret); 1317 1318 byte &= PCI_REBAR_CTRL_NBAR_MASK; 1319 byte >>= PCI_REBAR_CTRL_NBAR_SHIFT; 1320 1321 return 4 + (byte * 8); 1322 case PCI_EXT_CAP_ID_DPA: 1323 ret = pci_read_config_byte(pdev, epos + PCI_DPA_CAP, &byte); 1324 if (ret) 1325 return pcibios_err_to_errno(ret); 1326 1327 byte &= PCI_DPA_CAP_SUBSTATE_MASK; 1328 return PCI_DPA_BASE_SIZEOF + byte + 1; 1329 case PCI_EXT_CAP_ID_TPH: 1330 ret = pci_read_config_dword(pdev, epos + PCI_TPH_CAP, &dword); 1331 if (ret) 1332 return pcibios_err_to_errno(ret); 1333 1334 if ((dword & PCI_TPH_CAP_LOC_MASK) == PCI_TPH_LOC_CAP) { 1335 int sts; 1336 1337 sts = dword & PCI_TPH_CAP_ST_MASK; 1338 sts >>= PCI_TPH_CAP_ST_SHIFT; 1339 return PCI_TPH_BASE_SIZEOF + (sts * 2) + 2; 1340 } 1341 return PCI_TPH_BASE_SIZEOF; 1342 default: 1343 pr_warn("%s: %s unknown length for pci ecap 0x%x@0x%x\n", 1344 dev_name(&pdev->dev), __func__, ecap, epos); 1345 } 1346 1347 return 0; 1348 } 1349 1350 static int vfio_fill_vconfig_bytes(struct vfio_pci_device *vdev, 1351 int offset, int size) 1352 { 1353 struct pci_dev *pdev = vdev->pdev; 1354 int ret = 0; 1355 1356 /* 1357 * We try to read physical config space in the largest chunks 1358 * we can, assuming that all of the fields support dword access. 1359 * pci_save_state() makes this same assumption and seems to do ok. 1360 */ 1361 while (size) { 1362 int filled; 1363 1364 if (size >= 4 && !(offset % 4)) { 1365 __le32 *dwordp = (__le32 *)&vdev->vconfig[offset]; 1366 u32 dword; 1367 1368 ret = pci_read_config_dword(pdev, offset, &dword); 1369 if (ret) 1370 return ret; 1371 *dwordp = cpu_to_le32(dword); 1372 filled = 4; 1373 } else if (size >= 2 && !(offset % 2)) { 1374 __le16 *wordp = (__le16 *)&vdev->vconfig[offset]; 1375 u16 word; 1376 1377 ret = pci_read_config_word(pdev, offset, &word); 1378 if (ret) 1379 return ret; 1380 *wordp = cpu_to_le16(word); 1381 filled = 2; 1382 } else { 1383 u8 *byte = &vdev->vconfig[offset]; 1384 ret = pci_read_config_byte(pdev, offset, byte); 1385 if (ret) 1386 return ret; 1387 filled = 1; 1388 } 1389 1390 offset += filled; 1391 size -= filled; 1392 } 1393 1394 return ret; 1395 } 1396 1397 static int vfio_cap_init(struct vfio_pci_device *vdev) 1398 { 1399 struct pci_dev *pdev = vdev->pdev; 1400 u8 *map = vdev->pci_config_map; 1401 u16 status; 1402 u8 pos, *prev, cap; 1403 int loops, ret, caps = 0; 1404 1405 /* Any capabilities? */ 1406 ret = pci_read_config_word(pdev, PCI_STATUS, &status); 1407 if (ret) 1408 return ret; 1409 1410 if (!(status & PCI_STATUS_CAP_LIST)) 1411 return 0; /* Done */ 1412 1413 ret = pci_read_config_byte(pdev, PCI_CAPABILITY_LIST, &pos); 1414 if (ret) 1415 return ret; 1416 1417 /* Mark the previous position in case we want to skip a capability */ 1418 prev = &vdev->vconfig[PCI_CAPABILITY_LIST]; 1419 1420 /* We can bound our loop, capabilities are dword aligned */ 1421 loops = (PCI_CFG_SPACE_SIZE - PCI_STD_HEADER_SIZEOF) / PCI_CAP_SIZEOF; 1422 while (pos && loops--) { 1423 u8 next; 1424 int i, len = 0; 1425 1426 ret = pci_read_config_byte(pdev, pos, &cap); 1427 if (ret) 1428 return ret; 1429 1430 ret = pci_read_config_byte(pdev, 1431 pos + PCI_CAP_LIST_NEXT, &next); 1432 if (ret) 1433 return ret; 1434 1435 if (cap <= PCI_CAP_ID_MAX) { 1436 len = pci_cap_length[cap]; 1437 if (len == 0xFF) { /* Variable length */ 1438 len = vfio_cap_len(vdev, cap, pos); 1439 if (len < 0) 1440 return len; 1441 } 1442 } 1443 1444 if (!len) { 1445 pr_info("%s: %s hiding cap 0x%x\n", 1446 __func__, dev_name(&pdev->dev), cap); 1447 *prev = next; 1448 pos = next; 1449 continue; 1450 } 1451 1452 /* Sanity check, do we overlap other capabilities? */ 1453 for (i = 0; i < len; i++) { 1454 if (likely(map[pos + i] == PCI_CAP_ID_INVALID)) 1455 continue; 1456 1457 pr_warn("%s: %s pci config conflict @0x%x, was cap 0x%x now cap 0x%x\n", 1458 __func__, dev_name(&pdev->dev), 1459 pos + i, map[pos + i], cap); 1460 } 1461 1462 BUILD_BUG_ON(PCI_CAP_ID_MAX >= PCI_CAP_ID_INVALID_VIRT); 1463 1464 memset(map + pos, cap, len); 1465 ret = vfio_fill_vconfig_bytes(vdev, pos, len); 1466 if (ret) 1467 return ret; 1468 1469 prev = &vdev->vconfig[pos + PCI_CAP_LIST_NEXT]; 1470 pos = next; 1471 caps++; 1472 } 1473 1474 /* If we didn't fill any capabilities, clear the status flag */ 1475 if (!caps) { 1476 __le16 *vstatus = (__le16 *)&vdev->vconfig[PCI_STATUS]; 1477 *vstatus &= ~cpu_to_le16(PCI_STATUS_CAP_LIST); 1478 } 1479 1480 return 0; 1481 } 1482 1483 static int vfio_ecap_init(struct vfio_pci_device *vdev) 1484 { 1485 struct pci_dev *pdev = vdev->pdev; 1486 u8 *map = vdev->pci_config_map; 1487 u16 epos; 1488 __le32 *prev = NULL; 1489 int loops, ret, ecaps = 0; 1490 1491 if (!vdev->extended_caps) 1492 return 0; 1493 1494 epos = PCI_CFG_SPACE_SIZE; 1495 1496 loops = (pdev->cfg_size - PCI_CFG_SPACE_SIZE) / PCI_CAP_SIZEOF; 1497 1498 while (loops-- && epos >= PCI_CFG_SPACE_SIZE) { 1499 u32 header; 1500 u16 ecap; 1501 int i, len = 0; 1502 bool hidden = false; 1503 1504 ret = pci_read_config_dword(pdev, epos, &header); 1505 if (ret) 1506 return ret; 1507 1508 ecap = PCI_EXT_CAP_ID(header); 1509 1510 if (ecap <= PCI_EXT_CAP_ID_MAX) { 1511 len = pci_ext_cap_length[ecap]; 1512 if (len == 0xFF) { 1513 len = vfio_ext_cap_len(vdev, ecap, epos); 1514 if (len < 0) 1515 return ret; 1516 } 1517 } 1518 1519 if (!len) { 1520 pr_info("%s: %s hiding ecap 0x%x@0x%x\n", 1521 __func__, dev_name(&pdev->dev), ecap, epos); 1522 1523 /* If not the first in the chain, we can skip over it */ 1524 if (prev) { 1525 u32 val = epos = PCI_EXT_CAP_NEXT(header); 1526 *prev &= cpu_to_le32(~(0xffcU << 20)); 1527 *prev |= cpu_to_le32(val << 20); 1528 continue; 1529 } 1530 1531 /* 1532 * Otherwise, fill in a placeholder, the direct 1533 * readfn will virtualize this automatically 1534 */ 1535 len = PCI_CAP_SIZEOF; 1536 hidden = true; 1537 } 1538 1539 for (i = 0; i < len; i++) { 1540 if (likely(map[epos + i] == PCI_CAP_ID_INVALID)) 1541 continue; 1542 1543 pr_warn("%s: %s pci config conflict @0x%x, was ecap 0x%x now ecap 0x%x\n", 1544 __func__, dev_name(&pdev->dev), 1545 epos + i, map[epos + i], ecap); 1546 } 1547 1548 /* 1549 * Even though ecap is 2 bytes, we're currently a long way 1550 * from exceeding 1 byte capabilities. If we ever make it 1551 * up to 0xFE we'll need to up this to a two-byte, byte map. 1552 */ 1553 BUILD_BUG_ON(PCI_EXT_CAP_ID_MAX >= PCI_CAP_ID_INVALID_VIRT); 1554 1555 memset(map + epos, ecap, len); 1556 ret = vfio_fill_vconfig_bytes(vdev, epos, len); 1557 if (ret) 1558 return ret; 1559 1560 /* 1561 * If we're just using this capability to anchor the list, 1562 * hide the real ID. Only count real ecaps. XXX PCI spec 1563 * indicates to use cap id = 0, version = 0, next = 0 if 1564 * ecaps are absent, hope users check all the way to next. 1565 */ 1566 if (hidden) 1567 *(__le32 *)&vdev->vconfig[epos] &= 1568 cpu_to_le32((0xffcU << 20)); 1569 else 1570 ecaps++; 1571 1572 prev = (__le32 *)&vdev->vconfig[epos]; 1573 epos = PCI_EXT_CAP_NEXT(header); 1574 } 1575 1576 if (!ecaps) 1577 *(u32 *)&vdev->vconfig[PCI_CFG_SPACE_SIZE] = 0; 1578 1579 return 0; 1580 } 1581 1582 /* 1583 * For each device we allocate a pci_config_map that indicates the 1584 * capability occupying each dword and thus the struct perm_bits we 1585 * use for read and write. We also allocate a virtualized config 1586 * space which tracks reads and writes to bits that we emulate for 1587 * the user. Initial values filled from device. 1588 * 1589 * Using shared struct perm_bits between all vfio-pci devices saves 1590 * us from allocating cfg_size buffers for virt and write for every 1591 * device. We could remove vconfig and allocate individual buffers 1592 * for each area requiring emulated bits, but the array of pointers 1593 * would be comparable in size (at least for standard config space). 1594 */ 1595 int vfio_config_init(struct vfio_pci_device *vdev) 1596 { 1597 struct pci_dev *pdev = vdev->pdev; 1598 u8 *map, *vconfig; 1599 int ret; 1600 1601 /* 1602 * Config space, caps and ecaps are all dword aligned, so we could 1603 * use one byte per dword to record the type. However, there are 1604 * no requiremenst on the length of a capability, so the gap between 1605 * capabilities needs byte granularity. 1606 */ 1607 map = kmalloc(pdev->cfg_size, GFP_KERNEL); 1608 if (!map) 1609 return -ENOMEM; 1610 1611 vconfig = kmalloc(pdev->cfg_size, GFP_KERNEL); 1612 if (!vconfig) { 1613 kfree(map); 1614 return -ENOMEM; 1615 } 1616 1617 vdev->pci_config_map = map; 1618 vdev->vconfig = vconfig; 1619 1620 memset(map, PCI_CAP_ID_BASIC, PCI_STD_HEADER_SIZEOF); 1621 memset(map + PCI_STD_HEADER_SIZEOF, PCI_CAP_ID_INVALID, 1622 pdev->cfg_size - PCI_STD_HEADER_SIZEOF); 1623 1624 ret = vfio_fill_vconfig_bytes(vdev, 0, PCI_STD_HEADER_SIZEOF); 1625 if (ret) 1626 goto out; 1627 1628 vdev->bardirty = true; 1629 1630 /* 1631 * XXX can we just pci_load_saved_state/pci_restore_state? 1632 * may need to rebuild vconfig after that 1633 */ 1634 1635 /* For restore after reset */ 1636 vdev->rbar[0] = le32_to_cpu(*(__le32 *)&vconfig[PCI_BASE_ADDRESS_0]); 1637 vdev->rbar[1] = le32_to_cpu(*(__le32 *)&vconfig[PCI_BASE_ADDRESS_1]); 1638 vdev->rbar[2] = le32_to_cpu(*(__le32 *)&vconfig[PCI_BASE_ADDRESS_2]); 1639 vdev->rbar[3] = le32_to_cpu(*(__le32 *)&vconfig[PCI_BASE_ADDRESS_3]); 1640 vdev->rbar[4] = le32_to_cpu(*(__le32 *)&vconfig[PCI_BASE_ADDRESS_4]); 1641 vdev->rbar[5] = le32_to_cpu(*(__le32 *)&vconfig[PCI_BASE_ADDRESS_5]); 1642 vdev->rbar[6] = le32_to_cpu(*(__le32 *)&vconfig[PCI_ROM_ADDRESS]); 1643 1644 if (pdev->is_virtfn) { 1645 *(__le16 *)&vconfig[PCI_VENDOR_ID] = cpu_to_le16(pdev->vendor); 1646 *(__le16 *)&vconfig[PCI_DEVICE_ID] = cpu_to_le16(pdev->device); 1647 } 1648 1649 if (!IS_ENABLED(CONFIG_VFIO_PCI_INTX) || vdev->nointx) 1650 vconfig[PCI_INTERRUPT_PIN] = 0; 1651 1652 ret = vfio_cap_init(vdev); 1653 if (ret) 1654 goto out; 1655 1656 ret = vfio_ecap_init(vdev); 1657 if (ret) 1658 goto out; 1659 1660 return 0; 1661 1662 out: 1663 kfree(map); 1664 vdev->pci_config_map = NULL; 1665 kfree(vconfig); 1666 vdev->vconfig = NULL; 1667 return pcibios_err_to_errno(ret); 1668 } 1669 1670 void vfio_config_free(struct vfio_pci_device *vdev) 1671 { 1672 kfree(vdev->vconfig); 1673 vdev->vconfig = NULL; 1674 kfree(vdev->pci_config_map); 1675 vdev->pci_config_map = NULL; 1676 kfree(vdev->msi_perm); 1677 vdev->msi_perm = NULL; 1678 } 1679 1680 /* 1681 * Find the remaining number of bytes in a dword that match the given 1682 * position. Stop at either the end of the capability or the dword boundary. 1683 */ 1684 static size_t vfio_pci_cap_remaining_dword(struct vfio_pci_device *vdev, 1685 loff_t pos) 1686 { 1687 u8 cap = vdev->pci_config_map[pos]; 1688 size_t i; 1689 1690 for (i = 1; (pos + i) % 4 && vdev->pci_config_map[pos + i] == cap; i++) 1691 /* nop */; 1692 1693 return i; 1694 } 1695 1696 static ssize_t vfio_config_do_rw(struct vfio_pci_device *vdev, char __user *buf, 1697 size_t count, loff_t *ppos, bool iswrite) 1698 { 1699 struct pci_dev *pdev = vdev->pdev; 1700 struct perm_bits *perm; 1701 __le32 val = 0; 1702 int cap_start = 0, offset; 1703 u8 cap_id; 1704 ssize_t ret; 1705 1706 if (*ppos < 0 || *ppos >= pdev->cfg_size || 1707 *ppos + count > pdev->cfg_size) 1708 return -EFAULT; 1709 1710 /* 1711 * Chop accesses into aligned chunks containing no more than a 1712 * single capability. Caller increments to the next chunk. 1713 */ 1714 count = min(count, vfio_pci_cap_remaining_dword(vdev, *ppos)); 1715 if (count >= 4 && !(*ppos % 4)) 1716 count = 4; 1717 else if (count >= 2 && !(*ppos % 2)) 1718 count = 2; 1719 else 1720 count = 1; 1721 1722 ret = count; 1723 1724 cap_id = vdev->pci_config_map[*ppos]; 1725 1726 if (cap_id == PCI_CAP_ID_INVALID) { 1727 perm = &unassigned_perms; 1728 cap_start = *ppos; 1729 } else if (cap_id == PCI_CAP_ID_INVALID_VIRT) { 1730 perm = &virt_perms; 1731 cap_start = *ppos; 1732 } else { 1733 if (*ppos >= PCI_CFG_SPACE_SIZE) { 1734 WARN_ON(cap_id > PCI_EXT_CAP_ID_MAX); 1735 1736 perm = &ecap_perms[cap_id]; 1737 cap_start = vfio_find_cap_start(vdev, *ppos); 1738 } else { 1739 WARN_ON(cap_id > PCI_CAP_ID_MAX); 1740 1741 perm = &cap_perms[cap_id]; 1742 1743 if (cap_id == PCI_CAP_ID_MSI) 1744 perm = vdev->msi_perm; 1745 1746 if (cap_id > PCI_CAP_ID_BASIC) 1747 cap_start = vfio_find_cap_start(vdev, *ppos); 1748 } 1749 } 1750 1751 WARN_ON(!cap_start && cap_id != PCI_CAP_ID_BASIC); 1752 WARN_ON(cap_start > *ppos); 1753 1754 offset = *ppos - cap_start; 1755 1756 if (iswrite) { 1757 if (!perm->writefn) 1758 return ret; 1759 1760 if (copy_from_user(&val, buf, count)) 1761 return -EFAULT; 1762 1763 ret = perm->writefn(vdev, *ppos, count, perm, offset, val); 1764 } else { 1765 if (perm->readfn) { 1766 ret = perm->readfn(vdev, *ppos, count, 1767 perm, offset, &val); 1768 if (ret < 0) 1769 return ret; 1770 } 1771 1772 if (copy_to_user(buf, &val, count)) 1773 return -EFAULT; 1774 } 1775 1776 return ret; 1777 } 1778 1779 ssize_t vfio_pci_config_rw(struct vfio_pci_device *vdev, char __user *buf, 1780 size_t count, loff_t *ppos, bool iswrite) 1781 { 1782 size_t done = 0; 1783 int ret = 0; 1784 loff_t pos = *ppos; 1785 1786 pos &= VFIO_PCI_OFFSET_MASK; 1787 1788 while (count) { 1789 ret = vfio_config_do_rw(vdev, buf, count, &pos, iswrite); 1790 if (ret < 0) 1791 return ret; 1792 1793 count -= ret; 1794 done += ret; 1795 buf += ret; 1796 pos += ret; 1797 } 1798 1799 *ppos += done; 1800 1801 return done; 1802 } 1803