drivers/vfio/pci/vfio_pci_rdwr.c

   1 /*
   2  * VFIO PCI I/O Port & MMIO access
   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 #include <linux/fs.h>
  17 #include <linux/pci.h>
  18 #include <linux/uaccess.h>
  19 #include <linux/io.h>
  20 #include <linux/vfio.h>
  21 #include <linux/vgaarb.h>
  22
  23 #include "vfio_pci_private.h"
  24
  25 #ifdef __LITTLE_ENDIAN
  26 #define vfio_ioread64   ioread64
  27 #define vfio_iowrite64  iowrite64
  28 #define vfio_ioread32   ioread32
  29 #define vfio_iowrite32  iowrite32
  30 #define vfio_ioread16   ioread16
  31 #define vfio_iowrite16  iowrite16
  32 #else
  33 #define vfio_ioread64   ioread64be
  34 #define vfio_iowrite64  iowrite64be
  35 #define vfio_ioread32   ioread32be
  36 #define vfio_iowrite32  iowrite32be
  37 #define vfio_ioread16   ioread16be
  38 #define vfio_iowrite16  iowrite16be
  39 #endif
  40 #define vfio_ioread8    ioread8
  41 #define vfio_iowrite8   iowrite8
  42
  43 /*
  44  * Read or write from an __iomem region (MMIO or I/O port) with an excluded
  45  * range which is inaccessible.  The excluded range drops writes and fills
  46  * reads with -1.  This is intended for handling MSI-X vector tables and
  47  * leftover space for ROM BARs.
  48  */
  49 static ssize_t do_io_rw(void __iomem *io, char __user *buf,
  50                         loff_t off, size_t count, size_t x_start,
  51                         size_t x_end, bool iswrite)
  52 {
  53         ssize_t done = 0;
  54
  55         while (count) {
  56                 size_t fillable, filled;
  57
  58                 if (off < x_start)
  59                         fillable = min(count, (size_t)(x_start - off));
  60                 else if (off >= x_end)
  61                         fillable = count;
  62                 else
  63                         fillable = 0;
  64
  65                 if (fillable >= 4 && !(off % 4)) {
  66                         u32 val;
  67
  68                         if (iswrite) {
  69                                 if (copy_from_user(&val, buf, 4))
  70                                         return -EFAULT;
  71
  72                                 vfio_iowrite32(val, io + off);
  73                         } else {
  74                                 val = vfio_ioread32(io + off);
  75
  76                                 if (copy_to_user(buf, &val, 4))
  77                                         return -EFAULT;
  78                         }
  79
  80                         filled = 4;
  81                 } else if (fillable >= 2 && !(off % 2)) {
  82                         u16 val;
  83
  84                         if (iswrite) {
  85                                 if (copy_from_user(&val, buf, 2))
  86                                         return -EFAULT;
  87
  88                                 vfio_iowrite16(val, io + off);
  89                         } else {
  90                                 val = vfio_ioread16(io + off);
  91
  92                                 if (copy_to_user(buf, &val, 2))
  93                                         return -EFAULT;
  94                         }
  95
  96                         filled = 2;
  97                 } else if (fillable) {
  98                         u8 val;
  99
 100                         if (iswrite) {
 101                                 if (copy_from_user(&val, buf, 1))
 102                                         return -EFAULT;
 103
 104                                 vfio_iowrite8(val, io + off);
 105                         } else {
 106                                 val = vfio_ioread8(io + off);
 107
 108                                 if (copy_to_user(buf, &val, 1))
 109                                         return -EFAULT;
 110                         }
 111
 112                         filled = 1;
 113                 } else {
 114                         /* Fill reads with -1, drop writes */
 115                         filled = min(count, (size_t)(x_end - off));
 116                         if (!iswrite) {
 117                                 u8 val = 0xFF;
 118                                 size_t i;
 119
 120                                 for (i = 0; i < filled; i++)
 121                                         if (copy_to_user(buf + i, &val, 1))
 122                                                 return -EFAULT;
 123                         }
 124                 }
 125
 126                 count -= filled;
 127                 done += filled;
 128                 off += filled;
 129                 buf += filled;
 130         }
 131
 132         return done;
 133 }
 134
 135 static int vfio_pci_setup_barmap(struct vfio_pci_device *vdev, int bar)
 136 {
 137         struct pci_dev *pdev = vdev->pdev;
 138         int ret;
 139         void __iomem *io;
 140
 141         if (vdev->barmap[bar])
 142                 return 0;
 143
 144         ret = pci_request_selected_regions(pdev, 1 << bar, "vfio");
 145         if (ret)
 146                 return ret;
 147
 148         io = pci_iomap(pdev, bar, 0);
 149         if (!io) {
 150                 pci_release_selected_regions(pdev, 1 << bar);
 151                 return -ENOMEM;
 152         }
 153
 154         vdev->barmap[bar] = io;
 155
 156         return 0;
 157 }
 158
 159 ssize_t vfio_pci_bar_rw(struct vfio_pci_device *vdev, char __user *buf,
 160                         size_t count, loff_t *ppos, bool iswrite)
 161 {
 162         struct pci_dev *pdev = vdev->pdev;
 163         loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK;
 164         int bar = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
 165         size_t x_start = 0, x_end = 0;
 166         resource_size_t end;
 167         void __iomem *io;
 168         ssize_t done;
 169
 170         if (pci_resource_start(pdev, bar))
 171                 end = pci_resource_len(pdev, bar);
 172         else if (bar == PCI_ROM_RESOURCE &&
 173                  pdev->resource[bar].flags & IORESOURCE_ROM_SHADOW)
 174                 end = 0x20000;
 175         else
 176                 return -EINVAL;
 177
 178         if (pos >= end)
 179                 return -EINVAL;
 180
 181         count = min(count, (size_t)(end - pos));
 182
 183         if (bar == PCI_ROM_RESOURCE) {
 184                 /*
 185                  * The ROM can fill less space than the BAR, so we start the
 186                  * excluded range at the end of the actual ROM.  This makes
 187                  * filling large ROM BARs much faster.
 188                  */
 189                 io = pci_map_rom(pdev, &x_start);
 190                 if (!io)
 191                         return -ENOMEM;
 192                 x_end = end;
 193         } else {
 194                 int ret = vfio_pci_setup_barmap(vdev, bar);
 195                 if (ret)
 196                         return ret;
 197
 198                 io = vdev->barmap[bar];
 199         }
 200
 201         if (bar == vdev->msix_bar) {
 202                 x_start = vdev->msix_offset;
 203                 x_end = vdev->msix_offset + vdev->msix_size;
 204         }
 205
 206         done = do_io_rw(io, buf, pos, count, x_start, x_end, iswrite);
 207
 208         if (done >= 0)
 209                 *ppos += done;
 210
 211         if (bar == PCI_ROM_RESOURCE)
 212                 pci_unmap_rom(pdev, io);
 213
 214         return done;
 215 }
 216
 217 ssize_t vfio_pci_vga_rw(struct vfio_pci_device *vdev, char __user *buf,
 218                                size_t count, loff_t *ppos, bool iswrite)
 219 {
 220         int ret;
 221         loff_t off, pos = *ppos & VFIO_PCI_OFFSET_MASK;
 222         void __iomem *iomem = NULL;
 223         unsigned int rsrc;
 224         bool is_ioport;
 225         ssize_t done;
 226
 227         if (!vdev->has_vga)
 228                 return -EINVAL;
 229
 230         if (pos > 0xbfffful)
 231                 return -EINVAL;
 232
 233         switch ((u32)pos) {
 234         case 0xa0000 ... 0xbffff:
 235                 count = min(count, (size_t)(0xc0000 - pos));
 236                 iomem = ioremap_nocache(0xa0000, 0xbffff - 0xa0000 + 1);
 237                 off = pos - 0xa0000;
 238                 rsrc = VGA_RSRC_LEGACY_MEM;
 239                 is_ioport = false;
 240                 break;
 241         case 0x3b0 ... 0x3bb:
 242                 count = min(count, (size_t)(0x3bc - pos));
 243                 iomem = ioport_map(0x3b0, 0x3bb - 0x3b0 + 1);
 244                 off = pos - 0x3b0;
 245                 rsrc = VGA_RSRC_LEGACY_IO;
 246                 is_ioport = true;
 247                 break;
 248         case 0x3c0 ... 0x3df:
 249                 count = min(count, (size_t)(0x3e0 - pos));
 250                 iomem = ioport_map(0x3c0, 0x3df - 0x3c0 + 1);
 251                 off = pos - 0x3c0;
 252                 rsrc = VGA_RSRC_LEGACY_IO;
 253                 is_ioport = true;
 254                 break;
 255         default:
 256                 return -EINVAL;
 257         }
 258
 259         if (!iomem)
 260                 return -ENOMEM;
 261
 262         ret = vga_get_interruptible(vdev->pdev, rsrc);
 263         if (ret) {
 264                 is_ioport ? ioport_unmap(iomem) : iounmap(iomem);
 265                 return ret;
 266         }
 267
 268         done = do_io_rw(iomem, buf, off, count, 0, 0, iswrite);
 269
 270         vga_put(vdev->pdev, rsrc);
 271
 272         is_ioport ? ioport_unmap(iomem) : iounmap(iomem);
 273
 274         if (done >= 0)
 275                 *ppos += done;
 276
 277         return done;
 278 }
 279
 280 static int vfio_pci_ioeventfd_handler(void *opaque, void *unused)
 281 {
 282         struct vfio_pci_ioeventfd *ioeventfd = opaque;
 283
 284         switch (ioeventfd->count) {
 285         case 1:
 286                 vfio_iowrite8(ioeventfd->data, ioeventfd->addr);
 287                 break;
 288         case 2:
 289                 vfio_iowrite16(ioeventfd->data, ioeventfd->addr);
 290                 break;
 291         case 4:
 292                 vfio_iowrite32(ioeventfd->data, ioeventfd->addr);
 293                 break;
 294 #ifdef iowrite64
 295         case 8:
 296                 vfio_iowrite64(ioeventfd->data, ioeventfd->addr);
 297                 break;
 298 #endif
 299         }
 300
 301         return 0;
 302 }
 303
 304 long vfio_pci_ioeventfd(struct vfio_pci_device *vdev, loff_t offset,
 305                         uint64_t data, int count, int fd)
 306 {
 307         struct pci_dev *pdev = vdev->pdev;
 308         loff_t pos = offset & VFIO_PCI_OFFSET_MASK;
 309         int ret, bar = VFIO_PCI_OFFSET_TO_INDEX(offset);
 310         struct vfio_pci_ioeventfd *ioeventfd;
 311
 312         /* Only support ioeventfds into BARs */
 313         if (bar > VFIO_PCI_BAR5_REGION_INDEX)
 314                 return -EINVAL;
 315
 316         if (pos + count > pci_resource_len(pdev, bar))
 317                 return -EINVAL;
 318
 319         /* Disallow ioeventfds working around MSI-X table writes */
 320         if (bar == vdev->msix_bar &&
 321             !(pos + count <= vdev->msix_offset ||
 322               pos >= vdev->msix_offset + vdev->msix_size))
 323                 return -EINVAL;
 324
 325 #ifndef iowrite64
 326         if (count == 8)
 327                 return -EINVAL;
 328 #endif
 329
 330         ret = vfio_pci_setup_barmap(vdev, bar);
 331         if (ret)
 332                 return ret;
 333
 334         mutex_lock(&vdev->ioeventfds_lock);
 335
 336         list_for_each_entry(ioeventfd, &vdev->ioeventfds_list, next) {
 337                 if (ioeventfd->pos == pos && ioeventfd->bar == bar &&
 338                     ioeventfd->data == data && ioeventfd->count == count) {
 339                         if (fd == -1) {
 340                                 vfio_virqfd_disable(&ioeventfd->virqfd);
 341                                 list_del(&ioeventfd->next);
 342                                 vdev->ioeventfds_nr--;
 343                                 kfree(ioeventfd);
 344                                 ret = 0;
 345                         } else
 346                                 ret = -EEXIST;
 347
 348                         goto out_unlock;
 349                 }
 350         }
 351
 352         if (fd < 0) {
 353                 ret = -ENODEV;
 354                 goto out_unlock;
 355         }
 356
 357         if (vdev->ioeventfds_nr >= VFIO_PCI_IOEVENTFD_MAX) {
 358                 ret = -ENOSPC;
 359                 goto out_unlock;
 360         }
 361
 362         ioeventfd = kzalloc(sizeof(*ioeventfd), GFP_KERNEL);
 363         if (!ioeventfd) {
 364                 ret = -ENOMEM;
 365                 goto out_unlock;
 366         }
 367
 368         ioeventfd->addr = vdev->barmap[bar] + pos;
 369         ioeventfd->data = data;
 370         ioeventfd->pos = pos;
 371         ioeventfd->bar = bar;
 372         ioeventfd->count = count;
 373
 374         ret = vfio_virqfd_enable(ioeventfd, vfio_pci_ioeventfd_handler,
 375                                  NULL, NULL, &ioeventfd->virqfd, fd);
 376         if (ret) {
 377                 kfree(ioeventfd);
 378                 goto out_unlock;
 379         }
 380
 381         list_add(&ioeventfd->next, &vdev->ioeventfds_list);
 382         vdev->ioeventfds_nr++;
 383
 384 out_unlock:
 385         mutex_unlock(&vdev->ioeventfds_lock);
 386
 387         return ret;
 388 }