hw/msix.c

   1 /*
   2  * MSI-X device support
   3  *
   4  * This module includes support for MSI-X in pci devices.
   5  *
   6  * Author: Michael S. Tsirkin <mst@redhat.com>
   7  *
   8  *  Copyright (c) 2009, Red Hat Inc, Michael S. Tsirkin (mst@redhat.com)
   9  *
  10  * This work is licensed under the terms of the GNU GPL, version 2.  See
  11  * the COPYING file in the top-level directory.
  12  */
  13
  14 #include "hw.h"
  15 #include "msix.h"
  16 #include "pci.h"
  17
  18 /* Declaration from linux/pci_regs.h */
  19 #define  PCI_CAP_ID_MSIX 0x11 /* MSI-X */
  20 #define  PCI_MSIX_FLAGS 2     /* Table at lower 11 bits */
  21 #define  PCI_MSIX_FLAGS_QSIZE   0x7FF
  22 #define  PCI_MSIX_FLAGS_ENABLE  (1 << 15)
  23 #define  PCI_MSIX_FLAGS_BIRMASK (7 << 0)
  24
  25 /* MSI-X capability structure */
  26 #define MSIX_TABLE_OFFSET 4
  27 #define MSIX_PBA_OFFSET 8
  28 #define MSIX_CAP_LENGTH 12
  29
  30 /* MSI enable bit is in byte 1 in FLAGS register */
  31 #define MSIX_ENABLE_OFFSET (PCI_MSIX_FLAGS + 1)
  32 #define MSIX_ENABLE_MASK (PCI_MSIX_FLAGS_ENABLE >> 8)
  33
  34 /* MSI-X table format */
  35 #define MSIX_MSG_ADDR 0
  36 #define MSIX_MSG_UPPER_ADDR 4
  37 #define MSIX_MSG_DATA 8
  38 #define MSIX_VECTOR_CTRL 12
  39 #define MSIX_ENTRY_SIZE 16
  40 #define MSIX_VECTOR_MASK 0x1
  41
  42 /* How much space does an MSIX table need. */
  43 /* The spec requires giving the table structure
  44  * a 4K aligned region all by itself. */
  45 #define MSIX_PAGE_SIZE 0x1000
  46 /* Reserve second half of the page for pending bits */
  47 #define MSIX_PAGE_PENDING (MSIX_PAGE_SIZE / 2)
  48 #define MSIX_MAX_ENTRIES 32
  49
  50
  51 #ifdef MSIX_DEBUG
  52 #define DEBUG(fmt, ...)                                       \
  53     do {                                                      \
  54       fprintf(stderr, "%s: " fmt, __func__ , __VA_ARGS__);    \
  55     } while (0)
  56 #else
  57 #define DEBUG(fmt, ...) do { } while(0)
  58 #endif
  59
  60 /* Flag for interrupt controller to declare MSI-X support */
  61 int msix_supported;
  62
  63 /* Add MSI-X capability to the config space for the device. */
  64 /* Given a bar and its size, add MSI-X table on top of it
  65  * and fill MSI-X capability in the config space.
  66  * Original bar size must be a power of 2 or 0.
  67  * New bar size is returned. */
  68 static int msix_add_config(struct PCIDevice *pdev, unsigned short nentries,
  69                            unsigned bar_nr, unsigned bar_size)
  70 {
  71     int config_offset;
  72     uint8_t *config;
  73     uint32_t new_size;
  74
  75     if (nentries < 1 || nentries > PCI_MSIX_FLAGS_QSIZE + 1)
  76         return -EINVAL;
  77     if (bar_size > 0x80000000)
  78         return -ENOSPC;
  79
  80     /* Add space for MSI-X structures */
  81     if (!bar_size) {
  82         new_size = MSIX_PAGE_SIZE;
  83     } else if (bar_size < MSIX_PAGE_SIZE) {
  84         bar_size = MSIX_PAGE_SIZE;
  85         new_size = MSIX_PAGE_SIZE * 2;
  86     } else {
  87         new_size = bar_size * 2;
  88     }
  89
  90     pdev->msix_bar_size = new_size;
  91     config_offset = pci_add_capability(pdev, PCI_CAP_ID_MSIX, MSIX_CAP_LENGTH);
  92     if (config_offset < 0)
  93         return config_offset;
  94     config = pdev->config + config_offset;
  95
  96     pci_set_word(config + PCI_MSIX_FLAGS, nentries - 1);
  97     /* Table on top of BAR */
  98     pci_set_long(config + MSIX_TABLE_OFFSET, bar_size | bar_nr);
  99     /* Pending bits on top of that */
 100     pci_set_long(config + MSIX_PBA_OFFSET, (bar_size + MSIX_PAGE_PENDING) |
 101                  bar_nr);
 102     pdev->msix_cap = config_offset;
 103     /* Make flags bit writeable. */
 104     pdev->wmask[config_offset + MSIX_ENABLE_OFFSET] |= MSIX_ENABLE_MASK;
 105     return 0;
 106 }
 107
 108 /* Handle MSI-X capability config write. */
 109 void msix_write_config(PCIDevice *dev, uint32_t addr,
 110                        uint32_t val, int len)
 111 {
 112     unsigned enable_pos = dev->msix_cap + MSIX_ENABLE_OFFSET;
 113     if (addr + len <= enable_pos || addr > enable_pos)
 114         return;
 115
 116     if (msix_enabled(dev))
 117         qemu_set_irq(dev->irq[0], 0);
 118 }
 119
 120 static uint32_t msix_mmio_readl(void *opaque, target_phys_addr_t addr)
 121 {
 122     PCIDevice *dev = opaque;
 123     unsigned int offset = addr & (MSIX_PAGE_SIZE - 1) & ~0x3;
 124     void *page = dev->msix_table_page;
 125
 126     return pci_get_long(page + offset);
 127 }
 128
 129 static uint32_t msix_mmio_read_unallowed(void *opaque, target_phys_addr_t addr)
 130 {
 131     fprintf(stderr, "MSI-X: only dword read is allowed!\n");
 132     return 0;
 133 }
 134
 135 static uint8_t msix_pending_mask(int vector)
 136 {
 137     return 1 << (vector % 8);
 138 }
 139
 140 static uint8_t *msix_pending_byte(PCIDevice *dev, int vector)
 141 {
 142     return dev->msix_table_page + MSIX_PAGE_PENDING + vector / 8;
 143 }
 144
 145 static int msix_is_pending(PCIDevice *dev, int vector)
 146 {
 147     return *msix_pending_byte(dev, vector) & msix_pending_mask(vector);
 148 }
 149
 150 static void msix_set_pending(PCIDevice *dev, int vector)
 151 {
 152     *msix_pending_byte(dev, vector) |= msix_pending_mask(vector);
 153 }
 154
 155 static void msix_clr_pending(PCIDevice *dev, int vector)
 156 {
 157     *msix_pending_byte(dev, vector) &= ~msix_pending_mask(vector);
 158 }
 159
 160 static int msix_is_masked(PCIDevice *dev, int vector)
 161 {
 162     unsigned offset = vector * MSIX_ENTRY_SIZE + MSIX_VECTOR_CTRL;
 163     return dev->msix_table_page[offset] & MSIX_VECTOR_MASK;
 164 }
 165
 166 static void msix_mmio_writel(void *opaque, target_phys_addr_t addr,
 167                              uint32_t val)
 168 {
 169     PCIDevice *dev = opaque;
 170     unsigned int offset = addr & (MSIX_PAGE_SIZE - 1) & ~0x3;
 171     int vector = offset / MSIX_ENTRY_SIZE;
 172     pci_set_long(dev->msix_table_page + offset, val);
 173     if (!msix_is_masked(dev, vector) && msix_is_pending(dev, vector)) {
 174         msix_clr_pending(dev, vector);
 175         msix_notify(dev, vector);
 176     }
 177 }
 178
 179 static void msix_mmio_write_unallowed(void *opaque, target_phys_addr_t addr,
 180                                       uint32_t val)
 181 {
 182     fprintf(stderr, "MSI-X: only dword write is allowed!\n");
 183 }
 184
 185 static CPUWriteMemoryFunc * const msix_mmio_write[] = {
 186     msix_mmio_write_unallowed, msix_mmio_write_unallowed, msix_mmio_writel
 187 };
 188
 189 static CPUReadMemoryFunc * const msix_mmio_read[] = {
 190     msix_mmio_read_unallowed, msix_mmio_read_unallowed, msix_mmio_readl
 191 };
 192
 193 /* Should be called from device's map method. */
 194 void msix_mmio_map(PCIDevice *d, int region_num,
 195                    pcibus_t addr, pcibus_t size, int type)
 196 {
 197     uint8_t *config = d->config + d->msix_cap;
 198     uint32_t table = pci_get_long(config + MSIX_TABLE_OFFSET);
 199     uint32_t offset = table & ~(MSIX_PAGE_SIZE - 1);
 200     /* TODO: for assigned devices, we'll want to make it possible to map
 201      * pending bits separately in case they are in a separate bar. */
 202     int table_bir = table & PCI_MSIX_FLAGS_BIRMASK;
 203
 204     if (table_bir != region_num)
 205         return;
 206     if (size <= offset)
 207         return;
 208     cpu_register_physical_memory(addr + offset, size - offset,
 209                                  d->msix_mmio_index);
 210 }
 211
 212 static void msix_mask_all(struct PCIDevice *dev, unsigned nentries)
 213 {
 214     int vector;
 215     for (vector = 0; vector < nentries; ++vector) {
 216         unsigned offset = vector * MSIX_ENTRY_SIZE + MSIX_VECTOR_CTRL;
 217         dev->msix_table_page[offset] |= MSIX_VECTOR_MASK;
 218     }
 219 }
 220
 221 /* Initialize the MSI-X structures. Note: if MSI-X is supported, BAR size is
 222  * modified, it should be retrieved with msix_bar_size. */
 223 int msix_init(struct PCIDevice *dev, unsigned short nentries,
 224               unsigned bar_nr, unsigned bar_size)
 225 {
 226     int ret;
 227     /* Nothing to do if MSI is not supported by interrupt controller */
 228     if (!msix_supported)
 229         return -ENOTSUP;
 230
 231     if (nentries > MSIX_MAX_ENTRIES)
 232         return -EINVAL;
 233
 234     dev->msix_entry_used = qemu_mallocz(MSIX_MAX_ENTRIES *
 235                                         sizeof *dev->msix_entry_used);
 236
 237     dev->msix_table_page = qemu_mallocz(MSIX_PAGE_SIZE);
 238     msix_mask_all(dev, nentries);
 239
 240     dev->msix_mmio_index = cpu_register_io_memory(msix_mmio_read,
 241                                                   msix_mmio_write, dev);
 242     if (dev->msix_mmio_index == -1) {
 243         ret = -EBUSY;
 244         goto err_index;
 245     }
 246
 247     dev->msix_entries_nr = nentries;
 248     ret = msix_add_config(dev, nentries, bar_nr, bar_size);
 249     if (ret)
 250         goto err_config;
 251
 252     dev->cap_present |= QEMU_PCI_CAP_MSIX;
 253     return 0;
 254
 255 err_config:
 256     dev->msix_entries_nr = 0;
 257     cpu_unregister_io_memory(dev->msix_mmio_index);
 258 err_index:
 259     qemu_free(dev->msix_table_page);
 260     dev->msix_table_page = NULL;
 261     qemu_free(dev->msix_entry_used);
 262     dev->msix_entry_used = NULL;
 263     return ret;
 264 }
 265
 266 static void msix_free_irq_entries(PCIDevice *dev)
 267 {
 268     int vector;
 269
 270     for (vector = 0; vector < dev->msix_entries_nr; ++vector) {
 271         dev->msix_entry_used[vector] = 0;
 272         msix_clr_pending(dev, vector);
 273     }
 274 }
 275
 276 /* Clean up resources for the device. */
 277 int msix_uninit(PCIDevice *dev)
 278 {
 279     if (!(dev->cap_present & QEMU_PCI_CAP_MSIX))
 280         return 0;
 281     pci_del_capability(dev, PCI_CAP_ID_MSIX, MSIX_CAP_LENGTH);
 282     dev->msix_cap = 0;
 283     msix_free_irq_entries(dev);
 284     dev->msix_entries_nr = 0;
 285     cpu_unregister_io_memory(dev->msix_mmio_index);
 286     qemu_free(dev->msix_table_page);
 287     dev->msix_table_page = NULL;
 288     qemu_free(dev->msix_entry_used);
 289     dev->msix_entry_used = NULL;
 290     dev->cap_present &= ~QEMU_PCI_CAP_MSIX;
 291     return 0;
 292 }
 293
 294 void msix_save(PCIDevice *dev, QEMUFile *f)
 295 {
 296     unsigned n = dev->msix_entries_nr;
 297
 298     if (!(dev->cap_present & QEMU_PCI_CAP_MSIX)) {
 299         return;
 300     }
 301
 302     qemu_put_buffer(f, dev->msix_table_page, n * MSIX_ENTRY_SIZE);
 303     qemu_put_buffer(f, dev->msix_table_page + MSIX_PAGE_PENDING, (n + 7) / 8);
 304 }
 305
 306 /* Should be called after restoring the config space. */
 307 void msix_load(PCIDevice *dev, QEMUFile *f)
 308 {
 309     unsigned n = dev->msix_entries_nr;
 310
 311     if (!(dev->cap_present & QEMU_PCI_CAP_MSIX)) {
 312         return;
 313     }
 314
 315     msix_free_irq_entries(dev);
 316     qemu_get_buffer(f, dev->msix_table_page, n * MSIX_ENTRY_SIZE);
 317     qemu_get_buffer(f, dev->msix_table_page + MSIX_PAGE_PENDING, (n + 7) / 8);
 318 }
 319
 320 /* Does device support MSI-X? */
 321 int msix_present(PCIDevice *dev)
 322 {
 323     return dev->cap_present & QEMU_PCI_CAP_MSIX;
 324 }
 325
 326 /* Is MSI-X enabled? */
 327 int msix_enabled(PCIDevice *dev)
 328 {
 329     return (dev->cap_present & QEMU_PCI_CAP_MSIX) &&
 330         (dev->config[dev->msix_cap + MSIX_ENABLE_OFFSET] &
 331          MSIX_ENABLE_MASK);
 332 }
 333
 334 /* Size of bar where MSI-X table resides, or 0 if MSI-X not supported. */
 335 uint32_t msix_bar_size(PCIDevice *dev)
 336 {
 337     return (dev->cap_present & QEMU_PCI_CAP_MSIX) ?
 338         dev->msix_bar_size : 0;
 339 }
 340
 341 /* Send an MSI-X message */
 342 void msix_notify(PCIDevice *dev, unsigned vector)
 343 {
 344     uint8_t *table_entry = dev->msix_table_page + vector * MSIX_ENTRY_SIZE;
 345     uint64_t address;
 346     uint32_t data;
 347
 348     if (vector >= dev->msix_entries_nr || !dev->msix_entry_used[vector])
 349         return;
 350     if (msix_is_masked(dev, vector)) {
 351         msix_set_pending(dev, vector);
 352         return;
 353     }
 354
 355     address = pci_get_long(table_entry + MSIX_MSG_UPPER_ADDR);
 356     address = (address << 32) | pci_get_long(table_entry + MSIX_MSG_ADDR);
 357     data = pci_get_long(table_entry + MSIX_MSG_DATA);
 358     stl_phys(address, data);
 359 }
 360
 361 void msix_reset(PCIDevice *dev)
 362 {
 363     if (!(dev->cap_present & QEMU_PCI_CAP_MSIX))
 364         return;
 365     msix_free_irq_entries(dev);
 366     dev->config[dev->msix_cap + MSIX_ENABLE_OFFSET] &=
 367             ~dev->wmask[dev->msix_cap + MSIX_ENABLE_OFFSET];
 368     memset(dev->msix_table_page, 0, MSIX_PAGE_SIZE);
 369     msix_mask_all(dev, dev->msix_entries_nr);
 370 }
 371
 372 /* PCI spec suggests that devices make it possible for software to configure
 373  * less vectors than supported by the device, but does not specify a standard
 374  * mechanism for devices to do so.
 375  *
 376  * We support this by asking devices to declare vectors software is going to
 377  * actually use, and checking this on the notification path. Devices that
 378  * don't want to follow the spec suggestion can declare all vectors as used. */
 379
 380 /* Mark vector as used. */
 381 int msix_vector_use(PCIDevice *dev, unsigned vector)
 382 {
 383     if (vector >= dev->msix_entries_nr)
 384         return -EINVAL;
 385     dev->msix_entry_used[vector]++;
 386     return 0;
 387 }
 388
 389 /* Mark vector as unused. */
 390 void msix_vector_unuse(PCIDevice *dev, unsigned vector)
 391 {
 392     if (vector >= dev->msix_entries_nr || !dev->msix_entry_used[vector]) {
 393         return;
 394     }
 395     if (--dev->msix_entry_used[vector]) {
 396         return;
 397     }
 398     msix_clr_pending(dev, vector);
 399 }
 400
 401 void msix_unuse_all_vectors(PCIDevice *dev)
 402 {
 403     if (!(dev->cap_present & QEMU_PCI_CAP_MSIX))
 404         return;
 405     msix_free_irq_entries(dev);
 406 }