LXR qemu/hw/vfio/spapr.c

   1/*
   2 * DMA memory preregistration
   3 *
   4 * Authors:
   5 *  Alexey Kardashevskiy <aik@ozlabs.ru>
   6 *
   7 * This work is licensed under the terms of the GNU GPL, version 2.  See
   8 * the COPYING file in the top-level directory.
   9 */
  10
  11#include "qemu/osdep.h"
  12#include <sys/ioctl.h>
  13#include <linux/vfio.h>
  14
  15#include "hw/vfio/vfio-common.h"
  16#include "hw/hw.h"
  17#include "exec/ram_addr.h"
  18#include "qemu/error-report.h"
  19#include "qapi/error.h"
  20#include "trace.h"
  21
  22static bool vfio_prereg_listener_skipped_section(MemoryRegionSection *section)
  23{
  24    if (memory_region_is_iommu(section->mr)) {
  25        hw_error("Cannot possibly preregister IOMMU memory");
  26    }
  27
  28    return !memory_region_is_ram(section->mr) ||
  29            memory_region_is_ram_device(section->mr);
  30}
  31
  32static void *vfio_prereg_gpa_to_vaddr(MemoryRegionSection *section, hwaddr gpa)
  33{
  34    return memory_region_get_ram_ptr(section->mr) +
  35        section->offset_within_region +
  36        (gpa - section->offset_within_address_space);
  37}
  38
  39static void vfio_prereg_listener_region_add(MemoryListener *listener,
  40                                            MemoryRegionSection *section)
  41{
  42    VFIOContainer *container = container_of(listener, VFIOContainer,
  43                                            prereg_listener);
  44    const hwaddr gpa = section->offset_within_address_space;
  45    hwaddr end;
  46    int ret;
  47    hwaddr page_mask = qemu_real_host_page_mask;
  48    struct vfio_iommu_spapr_register_memory reg = {
  49        .argsz = sizeof(reg),
  50        .flags = 0,
  51    };
  52
  53    if (vfio_prereg_listener_skipped_section(section)) {
  54        trace_vfio_prereg_listener_region_add_skip(
  55                section->offset_within_address_space,
  56                section->offset_within_address_space +
  57                int128_get64(int128_sub(section->size, int128_one())));
  58        return;
  59    }
  60
  61    if (unlikely((section->offset_within_address_space & ~page_mask) ||
  62                 (section->offset_within_region & ~page_mask) ||
  63                 (int128_get64(section->size) & ~page_mask))) {
  64        error_report("%s received unaligned region", __func__);
  65        return;
  66    }
  67
  68    end = section->offset_within_address_space + int128_get64(section->size);
  69    if (gpa >= end) {
  70        return;
  71    }
  72
  73    memory_region_ref(section->mr);
  74
  75    reg.vaddr = (uintptr_t) vfio_prereg_gpa_to_vaddr(section, gpa);
  76    reg.size = end - gpa;
  77
  78    ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_REGISTER_MEMORY, &reg);
  79    trace_vfio_prereg_register(reg.vaddr, reg.size, ret ? -errno : 0);
  80    if (ret) {
  81        /*
  82         * On the initfn path, store the first error in the container so we
  83         * can gracefully fail.  Runtime, there's not much we can do other
  84         * than throw a hardware error.
  85         */
  86        if (!container->initialized) {
  87            if (!container->error) {
  88                error_setg_errno(&container->error, -ret,
  89                                 "Memory registering failed");
  90            }
  91        } else {
  92            hw_error("vfio: Memory registering failed, unable to continue");
  93        }
  94    }
  95}
  96
  97static void vfio_prereg_listener_region_del(MemoryListener *listener,
  98                                            MemoryRegionSection *section)
  99{
 100    VFIOContainer *container = container_of(listener, VFIOContainer,
 101                                            prereg_listener);
 102    const hwaddr gpa = section->offset_within_address_space;
 103    hwaddr end;
 104    int ret;
 105    hwaddr page_mask = qemu_real_host_page_mask;
 106    struct vfio_iommu_spapr_register_memory reg = {
 107        .argsz = sizeof(reg),
 108        .flags = 0,
 109    };
 110
 111    if (vfio_prereg_listener_skipped_section(section)) {
 112        trace_vfio_prereg_listener_region_del_skip(
 113                section->offset_within_address_space,
 114                section->offset_within_address_space +
 115                int128_get64(int128_sub(section->size, int128_one())));
 116        return;
 117    }
 118
 119    if (unlikely((section->offset_within_address_space & ~page_mask) ||
 120                 (section->offset_within_region & ~page_mask) ||
 121                 (int128_get64(section->size) & ~page_mask))) {
 122        error_report("%s received unaligned region", __func__);
 123        return;
 124    }
 125
 126    end = section->offset_within_address_space + int128_get64(section->size);
 127    if (gpa >= end) {
 128        return;
 129    }
 130
 131    reg.vaddr = (uintptr_t) vfio_prereg_gpa_to_vaddr(section, gpa);
 132    reg.size = end - gpa;
 133
 134    ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY, &reg);
 135    trace_vfio_prereg_unregister(reg.vaddr, reg.size, ret ? -errno : 0);
 136}
 137
 138const MemoryListener vfio_prereg_listener = {
 139    .region_add = vfio_prereg_listener_region_add,
 140    .region_del = vfio_prereg_listener_region_del,
 141};
 142
 143int vfio_spapr_create_window(VFIOContainer *container,
 144                             MemoryRegionSection *section,
 145                             hwaddr *pgsize)
 146{
 147    int ret = 0;
 148    IOMMUMemoryRegion *iommu_mr = IOMMU_MEMORY_REGION(section->mr);
 149    uint64_t pagesize = memory_region_iommu_get_min_page_size(iommu_mr), pgmask;
 150    unsigned entries, bits_total, bits_per_level, max_levels;
 151    struct vfio_iommu_spapr_tce_create create = { .argsz = sizeof(create) };
 152    long rampagesize = qemu_minrampagesize();
 153
 154    /*
 155     * The host might not support the guest supported IOMMU page size,
 156     * so we will use smaller physical IOMMU pages to back them.
 157     */
 158    if (pagesize > rampagesize) {
 159        pagesize = rampagesize;
 160    }
 161    pgmask = container->pgsizes & (pagesize | (pagesize - 1));
 162    pagesize = pgmask ? (1ULL << (63 - clz64(pgmask))) : 0;
 163    if (!pagesize) {
 164        error_report("Host doesn't support page size 0x%"PRIx64
 165                     ", the supported mask is 0x%lx",
 166                     memory_region_iommu_get_min_page_size(iommu_mr),
 167                     container->pgsizes);
 168        return -EINVAL;
 169    }
 170
 171    /*
 172     * FIXME: For VFIO iommu types which have KVM acceleration to
 173     * avoid bouncing all map/unmaps through qemu this way, this
 174     * would be the right place to wire that up (tell the KVM
 175     * device emulation the VFIO iommu handles to use).
 176     */
 177    create.window_size = int128_get64(section->size);
 178    create.page_shift = ctz64(pagesize);
 179    /*
 180     * SPAPR host supports multilevel TCE tables. We try to guess optimal
 181     * levels number and if this fails (for example due to the host memory
 182     * fragmentation), we increase levels. The DMA address structure is:
 183     * rrrrrrrr rxxxxxxx xxxxxxxx xxxxxxxx  xxxxxxxx xxxxxxxx xxxxxxxx iiiiiiii
 184     * where:
 185     *   r = reserved (bits >= 55 are reserved in the existing hardware)
 186     *   i = IOMMU page offset (64K in this example)
 187     *   x = bits to index a TCE which can be split to equal chunks to index
 188     *      within the level.
 189     * The aim is to split "x" to smaller possible number of levels.
 190     */
 191    entries = create.window_size >> create.page_shift;
 192    /* bits_total is number of "x" needed */
 193    bits_total = ctz64(entries * sizeof(uint64_t));
 194    /*
 195     * bits_per_level is a safe guess of how much we can allocate per level:
 196     * 8 is the current minimum for CONFIG_FORCE_MAX_ZONEORDER and MAX_ORDER
 197     * is usually bigger than that.
 198     * Below we look at qemu_real_host_page_size as TCEs are allocated from
 199     * system pages.
 200     */
 201    bits_per_level = ctz64(qemu_real_host_page_size) + 8;
 202    create.levels = bits_total / bits_per_level;
 203    if (bits_total % bits_per_level) {
 204        ++create.levels;
 205    }
 206    max_levels = (64 - create.page_shift) / ctz64(qemu_real_host_page_size);
 207    for ( ; create.levels <= max_levels; ++create.levels) {
 208        ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_CREATE, &create);
 209        if (!ret) {
 210            break;
 211        }
 212    }
 213    if (ret) {
 214        error_report("Failed to create a window, ret = %d (%m)", ret);
 215        return -errno;
 216    }
 217
 218    if (create.start_addr != section->offset_within_address_space) {
 219        vfio_spapr_remove_window(container, create.start_addr);
 220
 221        error_report("Host doesn't support DMA window at %"HWADDR_PRIx", must be %"PRIx64,
 222                     section->offset_within_address_space,
 223                     (uint64_t)create.start_addr);
 224        return -EINVAL;
 225    }
 226    trace_vfio_spapr_create_window(create.page_shift,
 227                                   create.levels,
 228                                   create.window_size,
 229                                   create.start_addr);
 230    *pgsize = pagesize;
 231
 232    return 0;
 233}
 234
 235int vfio_spapr_remove_window(VFIOContainer *container,
 236                             hwaddr offset_within_address_space)
 237{
 238    struct vfio_iommu_spapr_tce_remove remove = {
 239        .argsz = sizeof(remove),
 240        .start_addr = offset_within_address_space,
 241    };
 242    int ret;
 243
 244    ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_REMOVE, &remove);
 245    if (ret) {
 246        error_report("Failed to remove window at %"PRIx64,
 247                     (uint64_t)remove.start_addr);
 248        return -errno;
 249    }
 250
 251    trace_vfio_spapr_remove_window(offset_within_address_space);
 252
 253    return 0;
 254}
 255