main.c

   1 /*  Bare metal PPC KVM app, for libre-soc simulator comparison purposes
   2     Copyright (C) 2021 Lauri Kasanen
   3
   4     This program is free software: you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation, version 3 of the License.
   7
   8     This program is distributed in the hope that it will be useful,
   9     but WITHOUT ANY WARRANTY; without even the implied warranty of
  10     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11     GNU General Public License for more details.
  12
  13     You should have received a copy of the GNU General Public License
  14     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15 */
  16
  17 #define _GNU_SOURCE
  18
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <getopt.h>
  22 #include <linux/kvm.h>
  23 #include <limits.h>
  24 #include <stdio.h>
  25 #include <stdint.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <sys/ioctl.h>
  29 #include <sys/mman.h>
  30 #include <sys/stat.h>
  31 #include <sys/types.h>
  32 #include <unistd.h>
  33
  34 #define PAGE_SIZE (64 * 1024) // assumption
  35 #define MAXDUMPS 10
  36 #define RAMSIZE (64 * 1024 * 1024)
  37 #define PROGSTART 0x20000000
  38
  39 #define MSR_64  (1UL<<63)
  40 #define MSR_LE  (1UL<<0)
  41
  42 enum {
  43         SPR_LR,
  44 };
  45
  46 static void nukenewline(char buf[]) {
  47         unsigned i;
  48         for (i = 0; buf[i]; i++) {
  49                 if (buf[i] == '\n') {
  50                         buf[i] = '\0';
  51                         break;
  52                 }
  53         }
  54 }
  55
  56 static void help(const char argv0[]) {
  57
  58         printf("Usage: %s [args] -i file.bin\n\n"
  59
  60                 "-i --binary file       Raw, bare metal executable\n"
  61                 "-g --intregs file      Text file setting up GPRs\n"
  62                 "-f --fpregs file       Text file setting up FPRs\n"
  63                 "-s --spregs file       Text file setting up SPRs (unnecessary if only LR is needed)\n"
  64                 "-l --load file:addr    Load this binary to RAM\n"
  65                 "-d --dump file:addr:len        Save this RAM area after running\n"
  66                 "-t --trace file                Save a full trace to this file\n"
  67                 "-h --help              This help\n\n"
  68
  69                 "Load and dump may be given multiple times. GPR/FPR are numbered,\n"
  70                 "SPRs are named.\n", argv0);
  71
  72         exit(0);
  73 }
  74
  75 static void parseregs(const char name[], const uint8_t gpr, struct kvm_regs *regs,
  76                         struct kvm_fpu *fpregs) {
  77
  78         FILE *f = fopen(name, "r");
  79         if (!f) {
  80                 printf("Can't open %s\n", name);
  81                 exit(1);
  82         }
  83
  84         char buf[256];
  85
  86         while (fgets(buf, 256, f)) {
  87                 if (buf[0] == '#')
  88                         continue;
  89                 nukenewline(buf);
  90
  91                 const uint8_t reg = strtol(buf, NULL, 0);
  92                 const char *ptr = strchr(buf + 1, ' ');
  93                 if (!ptr) {
  94                         printf("Invalid line '%s'\n", buf);
  95                         continue;
  96                 }
  97
  98                 const uint64_t val = strtol(ptr, NULL, 0);
  99
 100                 // apply reg
 101                 if (gpr) {
 102                         regs->gpr[reg] = val;
 103                 } else {
 104                         fpregs->fpr[reg] = val;
 105                 }
 106         }
 107
 108         fclose(f);
 109 }
 110
 111 static void parsesprs(const char name[], struct kvm_regs *regs) {
 112
 113         FILE *f = fopen(name, "r");
 114         if (!f) {
 115                 printf("Can't open %s\n", name);
 116                 exit(1);
 117         }
 118
 119         char buf[256];
 120
 121         while (fgets(buf, 256, f)) {
 122                 if (buf[0] == '#')
 123                         continue;
 124                 nukenewline(buf);
 125
 126                 uint8_t reg = 0xff;
 127
 128                 #define check(a) if (!strncasecmp(buf, a, sizeof(a) - 1))
 129
 130                 check("LR:") {
 131                         reg = SPR_LR;
 132                 }
 133
 134                 #undef check
 135
 136                 if (reg == 0xff) {
 137                         printf("Unknown (unimplemented?) SPR register '%s'\n",
 138                                 buf);
 139                         continue;
 140                 }
 141
 142                 const char *ptr = strchr(buf + 1, ' ');
 143                 if (!ptr) {
 144                         printf("Invalid line '%s'\n", buf);
 145                         continue;
 146                 }
 147
 148                 const uint64_t val = strtol(ptr, NULL, 0);
 149
 150                 // apply reg
 151                 switch (reg) {
 152                         case SPR_LR:
 153                                 regs->lr = val;
 154                         break;
 155                 }
 156         }
 157
 158         fclose(f);
 159 }
 160
 161 static void load(const char arg[], uint8_t *ram) {
 162
 163         char name[PATH_MAX];
 164         const char *ptr = strchr(arg, ':');
 165         if (!ptr) {
 166                 printf("Invalid load\n");
 167                 exit(1);
 168         }
 169
 170         const unsigned namelen = ptr - arg;
 171
 172         strncpy(name, arg, namelen);
 173         name[namelen] = '\0';
 174
 175         const uint64_t addr = strtol(ptr + 1, NULL, 0);
 176
 177         FILE *f = fopen(name, "r");
 178         if (!f) {
 179                 printf("Can't open %s\n", name);
 180                 exit(1);
 181         }
 182
 183         fseek(f, 0, SEEK_END);
 184         const unsigned len = ftell(f);
 185         rewind(f);
 186
 187         if (addr + len >= RAMSIZE) {
 188                 printf("Tried to use too much RAM\n");
 189                 exit(1);
 190         }
 191
 192         printf("Loading %s to 0x%lx, %u bytes\n", name, addr, len);
 193
 194         if (fread(&ram[addr], len, 1, f) != 1)
 195                 abort();
 196
 197         fclose(f);
 198 }
 199
 200 static void setfpregs(const int vcpu, struct kvm_fpu *fpregs) {
 201         // KVM_[SG]ET_FPU isn't supported on PPC, we have to move individual regs...
 202         unsigned i;
 203         for (i = 0; i < 32; i++) {
 204                 struct kvm_one_reg r = {
 205                         .id = KVM_REG_PPC_FPR(i),
 206                         .addr = (uint64_t) &fpregs->fpr[i]
 207                 };
 208
 209                 if (ioctl(vcpu, KVM_SET_ONE_REG, &r) != 0)
 210                         abort();
 211         }
 212 }
 213
 214 static void getfpregs(const int vcpu, struct kvm_fpu *fpregs) {
 215         // KVM_[SG]ET_FPU isn't supported on PPC, we have to move individual regs...
 216         unsigned i;
 217         for (i = 0; i < 32; i++) {
 218                 struct kvm_one_reg r = {
 219                         .id = KVM_REG_PPC_FPR(i),
 220                         .addr = (uint64_t) &fpregs->fpr[i]
 221                 };
 222
 223                 if (ioctl(vcpu, KVM_GET_ONE_REG, &r) != 0)
 224                         abort();
 225         }
 226 }
 227
 228 int main(int argc, char **argv) {
 229
 230         const struct option longopts[] = {
 231                 { "binary", 1, NULL, 'i' },
 232                 { "intregs", 1, NULL, 'g' },
 233                 { "fpregs", 1, NULL, 'f' },
 234                 { "spregs", 1, NULL, 's' },
 235                 { "load", 1, NULL, 'l' },
 236                 { "dump", 1, NULL, 'd' },
 237                 { "trace", 1, NULL, 't' },
 238                 { "help", 0, NULL, 'h' },
 239                 { NULL, 0, NULL, 0 }
 240         };
 241         const char opts[] = "i:g:f:s:l:d:t:h";
 242
 243         struct kvm_run *run;
 244         struct kvm_regs regs;
 245         struct kvm_sregs sregs;
 246         struct kvm_fpu fpregs;
 247         int kvm, vmfd, vcpu;
 248         FILE *binary = NULL, *trace = NULL;
 249         char dumps[MAXDUMPS][PATH_MAX];
 250         unsigned num_dumps = 0;
 251         uint8_t *ram, *progmem;
 252         const char *binpath;
 253
 254         // Yes, we're frugal
 255         if (posix_memalign((void **) &ram, 64 * 1024, RAMSIZE))
 256                 abort();
 257         memset(ram, 0, RAMSIZE);
 258
 259         memset(&regs, 0, sizeof(struct kvm_regs));
 260         memset(&fpregs, 0, sizeof(struct kvm_fpu));
 261
 262         regs.lr = -1;
 263         regs.pc = PROGSTART;
 264         regs.msr = MSR_64 | MSR_LE;
 265
 266         while (1) {
 267                 const int c = getopt_long(argc, argv, opts, longopts, NULL);
 268                 if (c == -1)
 269                         break;
 270
 271                 switch (c) {
 272                         case 'i':
 273                                 if (binary) {
 274                                         printf("Only one binary allowed\n");
 275                                         return 1;
 276                                 }
 277
 278                                 binary = fopen(optarg, "r");
 279                                 if (!binary) {
 280                                         printf("Failed to open %s\n", optarg);
 281                                         return 1;
 282                                 }
 283
 284                                 binpath = strdup(optarg);
 285                         break;
 286                         case 'g':
 287                                 parseregs(optarg, 1, &regs, &fpregs);
 288                         break;
 289                         case 'f':
 290                                 parseregs(optarg, 0, &regs, &fpregs);
 291                         break;
 292                         case 's':
 293                                 parsesprs(optarg, &regs);
 294                         break;
 295                         case 'l':
 296                                 load(optarg, ram);
 297                         break;
 298                         case 'd':
 299                                 if (num_dumps >= MAXDUMPS) {
 300                                         printf("Too many dumps\n");
 301                                         return 1;
 302                                 }
 303
 304                                 strncpy(dumps[num_dumps], optarg, PATH_MAX);
 305                                 dumps[num_dumps][PATH_MAX - 1] = '\0';
 306                                 num_dumps++;
 307                         break;
 308                         case 't':
 309                                 if (trace) {
 310                                         printf("Only one trace allowed\n");
 311                                         return 1;
 312                                 }
 313
 314                                 trace = fopen(optarg, "w");
 315                                 if (!trace) {
 316                                         printf("Failed to open %s\n", optarg);
 317                                         return 1;
 318                                 }
 319                         break;
 320                         case 'h':
 321                         default:
 322                                 help(argv[0]);
 323                         break;
 324                 }
 325         }
 326
 327         if (!binary) {
 328                 help(argv[0]);
 329         }
 330
 331         fseek(binary, 0, SEEK_END);
 332         const unsigned binlen = ftell(binary);
 333         rewind(binary);
 334
 335         printf("Loading binary %u bytes\n", binlen);
 336
 337         const unsigned progmemlen = (binlen + (PAGE_SIZE - 1)) & ~(PAGE_SIZE - 1);
 338
 339         if (posix_memalign((void **) &progmem, 64 * 1024, progmemlen))
 340                 abort();
 341
 342         if (fread(progmem, binlen, 1, binary) != 1)
 343                 abort();
 344         fclose(binary);
 345
 346         kvm = open("/dev/kvm", O_RDWR | O_CLOEXEC);
 347         if (kvm < 0) {
 348                 printf("Failed to open kvm, perhaps you lack permissions?\n");
 349                 return 1;
 350         }
 351
 352         int ret;
 353         ret = ioctl(kvm, KVM_GET_API_VERSION, NULL);
 354         if (ret == -1 || ret != 12) abort();
 355
 356         ret = ioctl(kvm, KVM_CHECK_EXTENSION, KVM_CAP_PPC_GUEST_DEBUG_SSTEP);
 357         if (ret == -1 || !ret) {
 358                 printf("This system lacks single-stepping!\n");
 359                 return 1;
 360         }
 361
 362         vmfd = ioctl(kvm, KVM_CREATE_VM, (unsigned long)0);
 363
 364         struct kvm_userspace_memory_region region = {
 365                 .slot = 0,
 366                 .guest_phys_addr = 0,
 367                 .memory_size = RAMSIZE,
 368                 .userspace_addr = (uint64_t) ram,
 369                 .flags = 0
 370         };
 371         if (ioctl(vmfd, KVM_SET_USER_MEMORY_REGION, &region) == -1)
 372                 abort();
 373
 374         region.slot = 1;
 375         region.guest_phys_addr = PROGSTART;
 376         region.memory_size = progmemlen;
 377         region.userspace_addr = (uint64_t) progmem;
 378         region.flags = KVM_MEM_READONLY;
 379         if (ioctl(vmfd, KVM_SET_USER_MEMORY_REGION, &region) == -1)
 380                 abort();
 381
 382         vcpu = ioctl(vmfd, KVM_CREATE_VCPU, (unsigned long)0);
 383         const unsigned vcpulen = ioctl(kvm, KVM_GET_VCPU_MMAP_SIZE, NULL);
 384
 385         run = mmap(NULL, vcpulen, PROT_READ | PROT_WRITE, MAP_SHARED, vcpu, 0);
 386
 387         if (ioctl(vcpu, KVM_GET_SREGS, &sregs) == -1)
 388                 abort();
 389         if (ioctl(vcpu, KVM_SET_SREGS, &sregs) == -1)
 390                 abort();
 391
 392         if (ioctl(vcpu, KVM_SET_REGS, &regs) == -1)
 393                 abort();
 394         setfpregs(vcpu, &fpregs);
 395
 396         const struct kvm_guest_debug dbg = {
 397                 .control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP
 398         };
 399         if (ioctl(vcpu, KVM_SET_GUEST_DEBUG, &dbg) == -1)
 400                 abort();
 401
 402         // Runtime
 403         while (1) {
 404                 if (ioctl(vcpu, KVM_RUN, NULL) == -1)
 405                         abort();
 406                 printf("Exited because %u\n", run->exit_reason);
 407         }
 408
 409         close(kvm);
 410         free(progmem);
 411         free(ram);
 412         free((char *) binpath);
 413         return 0;
 414 }