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