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, ®); 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, ®); 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 } 256