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
  22 static 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
  32 static 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
  39 static 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
  97 static 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
 138 const MemoryListener vfio_prereg_listener = {
 139     .name = "vfio-pre-reg",
 140     .region_add = vfio_prereg_listener_region_add,
 141     .region_del = vfio_prereg_listener_region_del,
 142 };
 143
 144 int vfio_spapr_create_window(VFIOContainer *container,
 145                              MemoryRegionSection *section,
 146                              hwaddr *pgsize)
 147 {
 148     int ret = 0;
 149     IOMMUMemoryRegion *iommu_mr = IOMMU_MEMORY_REGION(section->mr);
 150     uint64_t pagesize = memory_region_iommu_get_min_page_size(iommu_mr), pgmask;
 151     unsigned entries, bits_total, bits_per_level, max_levels;
 152     struct vfio_iommu_spapr_tce_create create = { .argsz = sizeof(create) };
 153     long rampagesize = qemu_minrampagesize();
 154
 155     /*
 156      * The host might not support the guest supported IOMMU page size,
 157      * so we will use smaller physical IOMMU pages to back them.
 158      */
 159     if (pagesize > rampagesize) {
 160         pagesize = rampagesize;
 161     }
 162     pgmask = container->pgsizes & (pagesize | (pagesize - 1));
 163     pagesize = pgmask ? (1ULL << (63 - clz64(pgmask))) : 0;
 164     if (!pagesize) {
 165         error_report("Host doesn't support page size 0x%"PRIx64
 166                      ", the supported mask is 0x%lx",
 167                      memory_region_iommu_get_min_page_size(iommu_mr),
 168                      container->pgsizes);
 169         return -EINVAL;
 170     }
 171
 172     /*
 173      * FIXME: For VFIO iommu types which have KVM acceleration to
 174      * avoid bouncing all map/unmaps through qemu this way, this
 175      * would be the right place to wire that up (tell the KVM
 176      * device emulation the VFIO iommu handles to use).
 177      */
 178     create.window_size = int128_get64(section->size);
 179     create.page_shift = ctz64(pagesize);
 180     /*
 181      * SPAPR host supports multilevel TCE tables. We try to guess optimal
 182      * levels number and if this fails (for example due to the host memory
 183      * fragmentation), we increase levels. The DMA address structure is:
 184      * rrrrrrrr rxxxxxxx xxxxxxxx xxxxxxxx  xxxxxxxx xxxxxxxx xxxxxxxx iiiiiiii
 185      * where:
 186      *   r = reserved (bits >= 55 are reserved in the existing hardware)
 187      *   i = IOMMU page offset (64K in this example)
 188      *   x = bits to index a TCE which can be split to equal chunks to index
 189      *      within the level.
 190      * The aim is to split "x" to smaller possible number of levels.
 191      */
 192     entries = create.window_size >> create.page_shift;
 193     /* bits_total is number of "x" needed */
 194     bits_total = ctz64(entries * sizeof(uint64_t));
 195     /*
 196      * bits_per_level is a safe guess of how much we can allocate per level:
 197      * 8 is the current minimum for CONFIG_FORCE_MAX_ZONEORDER and MAX_ORDER
 198      * is usually bigger than that.
 199      * Below we look at qemu_real_host_page_size as TCEs are allocated from
 200      * system pages.
 201      */
 202     bits_per_level = ctz64(qemu_real_host_page_size) + 8;
 203     create.levels = bits_total / bits_per_level;
 204     if (bits_total % bits_per_level) {
 205         ++create.levels;
 206     }
 207     max_levels = (64 - create.page_shift) / ctz64(qemu_real_host_page_size);
 208     for ( ; create.levels <= max_levels; ++create.levels) {
 209         ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_CREATE, &create);
 210         if (!ret) {
 211             break;
 212         }
 213     }
 214     if (ret) {
 215         error_report("Failed to create a window, ret = %d (%m)", ret);
 216         return -errno;
 217     }
 218
 219     if (create.start_addr != section->offset_within_address_space) {
 220         vfio_spapr_remove_window(container, create.start_addr);
 221
 222         error_report("Host doesn't support DMA window at %"HWADDR_PRIx", must be %"PRIx64,
 223                      section->offset_within_address_space,
 224                      (uint64_t)create.start_addr);
 225         return -EINVAL;
 226     }
 227     trace_vfio_spapr_create_window(create.page_shift,
 228                                    create.levels,
 229                                    create.window_size,
 230                                    create.start_addr);
 231     *pgsize = pagesize;
 232
 233     return 0;
 234 }
 235
 236 int vfio_spapr_remove_window(VFIOContainer *container,
 237                              hwaddr offset_within_address_space)
 238 {
 239     struct vfio_iommu_spapr_tce_remove remove = {
 240         .argsz = sizeof(remove),
 241         .start_addr = offset_within_address_space,
 242     };
 243     int ret;
 244
 245     ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_REMOVE, &remove);
 246     if (ret) {
 247         error_report("Failed to remove window at %"PRIx64,
 248                      (uint64_t)remove.start_addr);
 249         return -errno;
 250     }
 251
 252     trace_vfio_spapr_remove_window(offset_within_address_space);
 253
 254     return 0;
 255 }