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 "cpu.h" 13 #include <sys/ioctl.h> 14 #include <linux/vfio.h> 15 16 #include "hw/vfio/vfio-common.h" 17 #include "hw/hw.h" 18 #include "exec/ram_addr.h" 19 #include "qemu/error-report.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 container->error = ret; 89 } 90 } else { 91 hw_error("vfio: Memory registering failed, unable to continue"); 92 } 93 } 94 } 95 96 static void vfio_prereg_listener_region_del(MemoryListener *listener, 97 MemoryRegionSection *section) 98 { 99 VFIOContainer *container = container_of(listener, VFIOContainer, 100 prereg_listener); 101 const hwaddr gpa = section->offset_within_address_space; 102 hwaddr end; 103 int ret; 104 hwaddr page_mask = qemu_real_host_page_mask; 105 struct vfio_iommu_spapr_register_memory reg = { 106 .argsz = sizeof(reg), 107 .flags = 0, 108 }; 109 110 if (vfio_prereg_listener_skipped_section(section)) { 111 trace_vfio_prereg_listener_region_del_skip( 112 section->offset_within_address_space, 113 section->offset_within_address_space + 114 int128_get64(int128_sub(section->size, int128_one()))); 115 return; 116 } 117 118 if (unlikely((section->offset_within_address_space & ~page_mask) || 119 (section->offset_within_region & ~page_mask) || 120 (int128_get64(section->size) & ~page_mask))) { 121 error_report("%s received unaligned region", __func__); 122 return; 123 } 124 125 end = section->offset_within_address_space + int128_get64(section->size); 126 if (gpa >= end) { 127 return; 128 } 129 130 reg.vaddr = (uintptr_t) vfio_prereg_gpa_to_vaddr(section, gpa); 131 reg.size = end - gpa; 132 133 ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY, ®); 134 trace_vfio_prereg_unregister(reg.vaddr, reg.size, ret ? -errno : 0); 135 } 136 137 const MemoryListener vfio_prereg_listener = { 138 .region_add = vfio_prereg_listener_region_add, 139 .region_del = vfio_prereg_listener_region_del, 140 }; 141 142 int vfio_spapr_create_window(VFIOContainer *container, 143 MemoryRegionSection *section, 144 hwaddr *pgsize) 145 { 146 int ret = 0; 147 IOMMUMemoryRegion *iommu_mr = IOMMU_MEMORY_REGION(section->mr); 148 uint64_t pagesize = memory_region_iommu_get_min_page_size(iommu_mr); 149 unsigned entries, bits_total, bits_per_level, max_levels; 150 struct vfio_iommu_spapr_tce_create create = { .argsz = sizeof(create) }; 151 long rampagesize = qemu_minrampagesize(); 152 153 /* 154 * The host might not support the guest supported IOMMU page size, 155 * so we will use smaller physical IOMMU pages to back them. 156 */ 157 if (pagesize > rampagesize) { 158 pagesize = rampagesize; 159 } 160 pagesize = 1ULL << (63 - clz64(container->pgsizes & 161 (pagesize | (pagesize - 1)))); 162 if (!pagesize) { 163 error_report("Host doesn't support page size 0x%"PRIx64 164 ", the supported mask is 0x%lx", 165 memory_region_iommu_get_min_page_size(iommu_mr), 166 container->pgsizes); 167 return -EINVAL; 168 } 169 170 /* 171 * FIXME: For VFIO iommu types which have KVM acceleration to 172 * avoid bouncing all map/unmaps through qemu this way, this 173 * would be the right place to wire that up (tell the KVM 174 * device emulation the VFIO iommu handles to use). 175 */ 176 create.window_size = int128_get64(section->size); 177 create.page_shift = ctz64(pagesize); 178 /* 179 * SPAPR host supports multilevel TCE tables. We try to guess optimal 180 * levels number and if this fails (for example due to the host memory 181 * fragmentation), we increase levels. The DMA address structure is: 182 * rrrrrrrr rxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx iiiiiiii 183 * where: 184 * r = reserved (bits >= 55 are reserved in the existing hardware) 185 * i = IOMMU page offset (64K in this example) 186 * x = bits to index a TCE which can be split to equal chunks to index 187 * within the level. 188 * The aim is to split "x" to smaller possible number of levels. 189 */ 190 entries = create.window_size >> create.page_shift; 191 /* bits_total is number of "x" needed */ 192 bits_total = ctz64(entries * sizeof(uint64_t)); 193 /* 194 * bits_per_level is a safe guess of how much we can allocate per level: 195 * 8 is the current minimum for CONFIG_FORCE_MAX_ZONEORDER and MAX_ORDER 196 * is usually bigger than that. 197 * Below we look at getpagesize() as TCEs are allocated from system pages. 198 */ 199 bits_per_level = ctz64(getpagesize()) + 8; 200 create.levels = bits_total / bits_per_level; 201 if (bits_total % bits_per_level) { 202 ++create.levels; 203 } 204 max_levels = (64 - create.page_shift) / ctz64(getpagesize()); 205 for ( ; create.levels <= max_levels; ++create.levels) { 206 ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_CREATE, &create); 207 if (!ret) { 208 break; 209 } 210 } 211 if (ret) { 212 error_report("Failed to create a window, ret = %d (%m)", ret); 213 return -errno; 214 } 215 216 if (create.start_addr != section->offset_within_address_space) { 217 vfio_spapr_remove_window(container, create.start_addr); 218 219 error_report("Host doesn't support DMA window at %"HWADDR_PRIx", must be %"PRIx64, 220 section->offset_within_address_space, 221 (uint64_t)create.start_addr); 222 return -EINVAL; 223 } 224 trace_vfio_spapr_create_window(create.page_shift, 225 create.levels, 226 create.window_size, 227 create.start_addr); 228 *pgsize = pagesize; 229 230 return 0; 231 } 232 233 int vfio_spapr_remove_window(VFIOContainer *container, 234 hwaddr offset_within_address_space) 235 { 236 struct vfio_iommu_spapr_tce_remove remove = { 237 .argsz = sizeof(remove), 238 .start_addr = offset_within_address_space, 239 }; 240 int ret; 241 242 ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_REMOVE, &remove); 243 if (ret) { 244 error_report("Failed to remove window at %"PRIx64, 245 (uint64_t)remove.start_addr); 246 return -errno; 247 } 248 249 trace_vfio_spapr_remove_window(offset_within_address_space); 250 251 return 0; 252 } 253