kvm-tpr-opt.c

   1 /*
   2  * tpr optimization for qemu/kvm
   3  *
   4  * Copyright (C) 2007-2008 Qumranet Technologies
   5  *
   6  * Licensed under the terms of the GNU GPL version 2 or higher.
   7  */
   8
   9 #include "config.h"
  10 #include "config-host.h"
  11
  12 #include <string.h>
  13
  14 #include "hw/hw.h"
  15 #include "hw/isa.h"
  16 #include "sysemu.h"
  17 #include "qemu-kvm.h"
  18 #include "cpu.h"
  19
  20 #include <stdio.h>
  21
  22 static uint64_t map_addr(struct kvm_sregs *sregs, target_ulong virt, unsigned *perms)
  23 {
  24     uint64_t mask = ((1ull << 48) - 1) & ~4095ull;
  25     uint64_t p, pp = 7;
  26
  27     p = sregs->cr3;
  28     if (sregs->cr4 & 0x20) {
  29         p &= ~31ull;
  30         p = ldq_phys(p + 8 * (virt >> 30));
  31         if (!(p & 1))
  32             return -1ull;
  33         p &= mask;
  34         p = ldq_phys(p + 8 * ((virt >> 21) & 511));
  35         if (!(p & 1))
  36             return -1ull;
  37         pp &= p;
  38         if (p & 128) {
  39             p += ((virt >> 12) & 511) << 12;
  40         } else {
  41             p &= mask;
  42             p = ldq_phys(p + 8 * ((virt >> 12) & 511));
  43             if (!(p & 1))
  44                 return -1ull;
  45             pp &= p;
  46         }
  47     } else {
  48         p &= mask;
  49         p = ldl_phys(p + 4 * ((virt >> 22) & 1023));
  50         if (!(p & 1))
  51             return -1ull;
  52         pp &= p;
  53         if (p & 128) {
  54             p += ((virt >> 12) & 1023) << 12;
  55         } else {
  56             p &= mask;
  57             p = ldl_phys(p + 4 * ((virt >> 12) & 1023));
  58             pp &= p;
  59             if (!(p & 1))
  60                 return -1ull;
  61         }
  62     }
  63     if (perms)
  64         *perms = pp >> 1;
  65     p &= mask;
  66     return p + (virt & 4095);
  67 }
  68
  69 static uint8_t read_byte_virt(CPUState *env, target_ulong virt)
  70 {
  71     struct kvm_sregs sregs;
  72
  73     kvm_get_sregs(env, &sregs);
  74     return ldub_phys(map_addr(&sregs, virt, NULL));
  75 }
  76
  77 static void write_byte_virt(CPUState *env, target_ulong virt, uint8_t b)
  78 {
  79     struct kvm_sregs sregs;
  80
  81     kvm_get_sregs(env, &sregs);
  82     stb_phys(map_addr(&sregs, virt, NULL), b);
  83 }
  84
  85 static __u64 kvm_rsp_read(CPUState *env)
  86 {
  87     struct kvm_regs regs;
  88
  89     kvm_get_regs(env, &regs);
  90     return regs.rsp;
  91 }
  92
  93 struct vapic_bios {
  94     char signature[8];
  95     uint32_t virt_base;
  96     uint32_t fixup_start;
  97     uint32_t fixup_end;
  98     uint32_t vapic;
  99     uint32_t vapic_size;
 100     uint32_t vcpu_shift;
 101     uint32_t real_tpr;
 102     struct vapic_patches {
 103         uint32_t set_tpr;
 104         uint32_t set_tpr_eax;
 105         uint32_t get_tpr[8];
 106         uint32_t get_tpr_stack;
 107     } __attribute__((packed)) up, mp;
 108 } __attribute__((packed));
 109
 110 static struct vapic_bios vapic_bios;
 111
 112 static uint32_t real_tpr;
 113 static uint32_t bios_addr;
 114 static uint32_t vapic_phys;
 115 static uint32_t bios_enabled;
 116 static uint32_t vbios_desc_phys;
 117 static uint32_t vapic_bios_addr;
 118
 119 static void update_vbios_real_tpr(void)
 120 {
 121     cpu_physical_memory_rw(vbios_desc_phys, (void *)&vapic_bios, sizeof vapic_bios, 0);
 122     vapic_bios.real_tpr = real_tpr;
 123     vapic_bios.vcpu_shift = 7;
 124     cpu_physical_memory_rw(vbios_desc_phys, (void *)&vapic_bios, sizeof vapic_bios, 1);
 125 }
 126
 127 static unsigned modrm_reg(uint8_t modrm)
 128 {
 129     return (modrm >> 3) & 7;
 130 }
 131
 132 static int is_abs_modrm(uint8_t modrm)
 133 {
 134     return (modrm & 0xc7) == 0x05;
 135 }
 136
 137 static int instruction_is_ok(CPUState *env, uint64_t rip, int is_write)
 138 {
 139     uint8_t b1, b2;
 140     unsigned addr_offset;
 141     uint32_t addr;
 142     uint64_t p;
 143
 144     if ((rip & 0xf0000000) != 0x80000000 && (rip & 0xf0000000) != 0xe0000000)
 145         return 0;
 146     if (kvm_rsp_read(env) == 0)
 147         return 0;
 148     b1 = read_byte_virt(env, rip);
 149     b2 = read_byte_virt(env, rip + 1);
 150     switch (b1) {
 151     case 0xc7: /* mov imm32, r/m32 (c7/0) */
 152         if (modrm_reg(b2) != 0)
 153             return 0;
 154         /* fall through */
 155     case 0x89: /* mov r32 to r/m32 */
 156     case 0x8b: /* mov r/m32 to r32 */
 157         if (!is_abs_modrm(b2))
 158             return 0;
 159         addr_offset = 2;
 160         break;
 161     case 0xa1: /* mov abs to eax */
 162     case 0xa3: /* mov eax to abs */
 163         addr_offset = 1;
 164         break;
 165     case 0xff: /* push r/m32 */
 166         if (modrm_reg(b2) != 6 || !is_abs_modrm(b2))
 167             return 0;
 168         addr_offset = 2;
 169     default:
 170         return 0;
 171     }
 172     p = rip + addr_offset;
 173     addr = read_byte_virt(env, p++);
 174     addr |= read_byte_virt(env, p++) << 8;
 175     addr |= read_byte_virt(env, p++) << 16;
 176     addr |= read_byte_virt(env, p++) << 24;
 177     if ((addr & 0xfff) != 0x80)
 178         return 0;
 179     real_tpr = addr;
 180     update_vbios_real_tpr();
 181     return 1;
 182 }
 183
 184 static int bios_is_mapped(CPUState *env, uint64_t rip)
 185 {
 186     uint32_t probe;
 187     uint64_t phys;
 188     struct kvm_sregs sregs;
 189     unsigned perms;
 190     uint32_t i;
 191     uint32_t offset, fixup, start = vapic_bios_addr ? : 0xe0000;
 192
 193     if (bios_enabled)
 194         return 1;
 195
 196     kvm_get_sregs(env, &sregs);
 197
 198     probe = (rip & 0xf0000000) + start;
 199     phys = map_addr(&sregs, probe, &perms);
 200     if (phys != start)
 201         return 0;
 202     bios_addr = probe;
 203     for (i = 0; i < 64; ++i) {
 204         cpu_physical_memory_read(phys, (void *)&vapic_bios, sizeof(vapic_bios));
 205         if (memcmp(vapic_bios.signature, "kvm aPiC", 8) == 0)
 206             break;
 207         phys += 1024;
 208         bios_addr += 1024;
 209     }
 210     if (i == 64)
 211         return 0;
 212     if (bios_addr == vapic_bios.virt_base)
 213         return 1;
 214     vbios_desc_phys = phys;
 215     for (i = vapic_bios.fixup_start; i < vapic_bios.fixup_end; i += 4) {
 216         offset = ldl_phys(phys + i - vapic_bios.virt_base);
 217         fixup = phys + offset;
 218         stl_phys(fixup, ldl_phys(fixup) + bios_addr - vapic_bios.virt_base);
 219     }
 220     vapic_phys = vapic_bios.vapic - vapic_bios.virt_base + phys;
 221     return 1;
 222 }
 223
 224 static int get_pcr_cpu(CPUState *env)
 225 {
 226     uint8_t b;
 227
 228     kvm_save_registers(env);
 229
 230     if (cpu_memory_rw_debug(env, env->segs[R_FS].base + 0x51, &b, 1, 0) < 0)
 231             return -1;
 232
 233     return (int)b;
 234 }
 235
 236 static int enable_vapic(CPUState *env)
 237 {
 238     static uint8_t one = 1;
 239     int pcr_cpu = get_pcr_cpu(env);
 240
 241     if (pcr_cpu < 0)
 242             return 0;
 243
 244     kvm_enable_vapic(env, vapic_phys + (pcr_cpu << 7));
 245     cpu_physical_memory_rw(vapic_phys + (pcr_cpu << 7) + 4, &one, 1, 1);
 246     bios_enabled = 1;
 247
 248     return 1;
 249 }
 250
 251 static void patch_call(CPUState *env, uint64_t rip, uint32_t target)
 252 {
 253     uint32_t offset;
 254
 255     offset = target - vapic_bios.virt_base + bios_addr - rip - 5;
 256     write_byte_virt(env, rip, 0xe8); /* call near */
 257     write_byte_virt(env, rip + 1, offset);
 258     write_byte_virt(env, rip + 2, offset >> 8);
 259     write_byte_virt(env, rip + 3, offset >> 16);
 260     write_byte_virt(env, rip + 4, offset >> 24);
 261 }
 262
 263 static void patch_instruction(CPUState *env, uint64_t rip)
 264 {
 265     uint8_t b1, b2;
 266     struct vapic_patches *vp;
 267
 268     vp = smp_cpus == 1 ? &vapic_bios.up : &vapic_bios.mp;
 269     b1 = read_byte_virt(env, rip);
 270     b2 = read_byte_virt(env, rip + 1);
 271     switch (b1) {
 272     case 0x89: /* mov r32 to r/m32 */
 273         write_byte_virt(env, rip, 0x50 + modrm_reg(b2));  /* push reg */
 274         patch_call(env, rip + 1, vp->set_tpr);
 275         break;
 276     case 0x8b: /* mov r/m32 to r32 */
 277         write_byte_virt(env, rip, 0x90);
 278         patch_call(env, rip + 1, vp->get_tpr[modrm_reg(b2)]);
 279         break;
 280     case 0xa1: /* mov abs to eax */
 281         patch_call(env, rip, vp->get_tpr[0]);
 282         break;
 283     case 0xa3: /* mov eax to abs */
 284         patch_call(env, rip, vp->set_tpr_eax);
 285         break;
 286     case 0xc7: /* mov imm32, r/m32 (c7/0) */
 287         write_byte_virt(env, rip, 0x68);  /* push imm32 */
 288         write_byte_virt(env, rip + 1, read_byte_virt(env, rip+6));
 289         write_byte_virt(env, rip + 2, read_byte_virt(env, rip+7));
 290         write_byte_virt(env, rip + 3, read_byte_virt(env, rip+8));
 291         write_byte_virt(env, rip + 4, read_byte_virt(env, rip+9));
 292         patch_call(env, rip + 5, vp->set_tpr);
 293         break;
 294     case 0xff: /* push r/m32 */
 295         printf("patching push\n");
 296         write_byte_virt(env, rip, 0x50); /* push eax */
 297         patch_call(env, rip + 1, vp->get_tpr_stack);
 298         break;
 299     default:
 300         printf("funny insn %02x %02x\n", b1, b2);
 301     }
 302 }
 303
 304 void kvm_tpr_access_report(CPUState *env, uint64_t rip, int is_write)
 305 {
 306     if (!instruction_is_ok(env, rip, is_write))
 307         return;
 308     if (!bios_is_mapped(env, rip))
 309         return;
 310     if (!enable_vapic(env))
 311         return;
 312     patch_instruction(env, rip);
 313 }
 314
 315 void kvm_tpr_vcpu_start(CPUState *env)
 316 {
 317     kvm_enable_tpr_access_reporting(env);
 318     if (bios_enabled)
 319         enable_vapic(env);
 320 }
 321
 322 static void tpr_save(QEMUFile *f, void *s)
 323 {
 324     int i;
 325
 326     for (i = 0; i < (sizeof vapic_bios) / 4; ++i)
 327         qemu_put_be32s(f, &((uint32_t *)&vapic_bios)[i]);
 328     qemu_put_be32s(f, &bios_enabled);
 329     qemu_put_be32s(f, &real_tpr);
 330     qemu_put_be32s(f, &bios_addr);
 331     qemu_put_be32s(f, &vapic_phys);
 332     qemu_put_be32s(f, &vbios_desc_phys);
 333 }
 334
 335 static int tpr_load(QEMUFile *f, void *s, int version_id)
 336 {
 337     int i;
 338
 339     if (version_id != 1)
 340         return -EINVAL;
 341
 342     for (i = 0; i < (sizeof vapic_bios) / 4; ++i)
 343         qemu_get_be32s(f, &((uint32_t *)&vapic_bios)[i]);
 344     qemu_get_be32s(f, &bios_enabled);
 345     qemu_get_be32s(f, &real_tpr);
 346     qemu_get_be32s(f, &bios_addr);
 347     qemu_get_be32s(f, &vapic_phys);
 348     qemu_get_be32s(f, &vbios_desc_phys);
 349
 350     if (bios_enabled) {
 351         CPUState *env = first_cpu->next_cpu;
 352
 353         for (env = first_cpu; env != NULL; env = env->next_cpu)
 354             enable_vapic(env);
 355     }
 356
 357     return 0;
 358 }
 359
 360 static void vtpr_ioport_write16(void *opaque, uint32_t addr, uint32_t val)
 361 {
 362     struct kvm_regs regs;
 363     CPUState *env = cpu_single_env;
 364     struct kvm_sregs sregs;
 365     kvm_get_regs(env, &regs);
 366     kvm_get_sregs(env, &sregs);
 367     vapic_bios_addr = ((sregs.cs.base + regs.rip) & ~(512 - 1)) + val;
 368     bios_enabled = 0;
 369 }
 370
 371 static void vtpr_ioport_write(void *opaque, uint32_t addr, uint32_t val)
 372 {
 373     CPUState *env = cpu_single_env;
 374     struct kvm_regs regs;
 375     struct kvm_sregs sregs;
 376     uint32_t rip;
 377
 378     kvm_get_regs(env, &regs);
 379     rip = regs.rip - 2;
 380     write_byte_virt(env, rip, 0x66);
 381     write_byte_virt(env, rip + 1, 0x90);
 382     if (bios_enabled)
 383         return;
 384     if (!bios_is_mapped(env, rip))
 385         printf("bios not mapped?\n");
 386     kvm_get_sregs(env, &sregs);
 387     for (addr = 0xfffff000u; addr >= 0x80000000u; addr -= 4096)
 388         if (map_addr(&sregs, addr, NULL) == 0xfee00000u) {
 389             real_tpr = addr + 0x80;
 390             break;
 391         }
 392     bios_enabled = 1;
 393     update_vbios_real_tpr();
 394     enable_vapic(env);
 395 }
 396
 397 void kvm_tpr_opt_setup(void)
 398 {
 399     register_savevm("kvm-tpr-opt", 0, 1, tpr_save, tpr_load, NULL);
 400     register_ioport_write(0x7e, 1, 1, vtpr_ioport_write, NULL);
 401     register_ioport_write(0x7e, 2, 2, vtpr_ioport_write16, NULL);
 402 }
 403