SAFE public projects git trees. - safe/jmp/linux-2.6/blob - arch/x86/kvm/lapic.c

   1
   2 /*
   3  * Local APIC virtualization
   4  *
   5  * Copyright (C) 2006 Qumranet, Inc.
   6  * Copyright (C) 2007 Novell
   7  * Copyright (C) 2007 Intel
   8  *
   9  * Authors:
  10  *   Dor Laor <dor.laor@qumranet.com>
  11  *   Gregory Haskins <ghaskins@novell.com>
  12  *   Yaozu (Eddie) Dong <eddie.dong@intel.com>
  13  *
  14  * Based on Xen 3.1 code, Copyright (c) 2004, Intel Corporation.
  15  *
  16  * This work is licensed under the terms of the GNU GPL, version 2.  See
  17  * the COPYING file in the top-level directory.
  18  */
  19
  20 #include <linux/kvm_host.h>
  21 #include <linux/kvm.h>
  22 #include <linux/mm.h>
  23 #include <linux/highmem.h>
  24 #include <linux/smp.h>
  25 #include <linux/hrtimer.h>
  26 #include <linux/io.h>
  27 #include <linux/module.h>
  28 #include <linux/math64.h>
  29 #include <asm/processor.h>
  30 #include <asm/msr.h>
  31 #include <asm/page.h>
  32 #include <asm/current.h>
  33 #include <asm/apicdef.h>
  34 #include <asm/atomic.h>
  35 #include <asm/apicdef.h>
  36 #include "kvm_cache_regs.h"
  37 #include "irq.h"
  38 #include "trace.h"
  39 #include "x86.h"
  40
  41 #ifndef CONFIG_X86_64
  42 #define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
  43 #else
  44 #define mod_64(x, y) ((x) % (y))
  45 #endif
  46
  47 #define PRId64 "d"
  48 #define PRIx64 "llx"
  49 #define PRIu64 "u"
  50 #define PRIo64 "o"
  51
  52 #define APIC_BUS_CYCLE_NS 1
  53
  54 /* #define apic_debug(fmt,arg...) printk(KERN_WARNING fmt,##arg) */
  55 #define apic_debug(fmt, arg...)
  56
  57 #define APIC_LVT_NUM                    6
  58 /* 14 is the version for Xeon and Pentium 8.4.8*/
  59 #define APIC_VERSION                    (0x14UL | ((APIC_LVT_NUM - 1) << 16))
  60 #define LAPIC_MMIO_LENGTH               (1 << 12)
  61 /* followed define is not in apicdef.h */
  62 #define APIC_SHORT_MASK                 0xc0000
  63 #define APIC_DEST_NOSHORT               0x0
  64 #define APIC_DEST_MASK                  0x800
  65 #define MAX_APIC_VECTOR                 256
  66
  67 #define VEC_POS(v) ((v) & (32 - 1))
  68 #define REG_POS(v) (((v) >> 5) << 4)
  69
  70 static inline u32 apic_get_reg(struct kvm_lapic *apic, int reg_off)
  71 {
  72         return *((u32 *) (apic->regs + reg_off));
  73 }
  74
  75 static inline void apic_set_reg(struct kvm_lapic *apic, int reg_off, u32 val)
  76 {
  77         *((u32 *) (apic->regs + reg_off)) = val;
  78 }
  79
  80 static inline int apic_test_and_set_vector(int vec, void *bitmap)
  81 {
  82         return test_and_set_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
  83 }
  84
  85 static inline int apic_test_and_clear_vector(int vec, void *bitmap)
  86 {
  87         return test_and_clear_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
  88 }
  89
  90 static inline void apic_set_vector(int vec, void *bitmap)
  91 {
  92         set_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
  93 }
  94
  95 static inline void apic_clear_vector(int vec, void *bitmap)
  96 {
  97         clear_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
  98 }
  99
 100 static inline int apic_hw_enabled(struct kvm_lapic *apic)
 101 {
 102         return (apic)->vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE;
 103 }
 104
 105 static inline int  apic_sw_enabled(struct kvm_lapic *apic)
 106 {
 107         return apic_get_reg(apic, APIC_SPIV) & APIC_SPIV_APIC_ENABLED;
 108 }
 109
 110 static inline int apic_enabled(struct kvm_lapic *apic)
 111 {
 112         return apic_sw_enabled(apic) && apic_hw_enabled(apic);
 113 }
 114
 115 #define LVT_MASK        \
 116         (APIC_LVT_MASKED | APIC_SEND_PENDING | APIC_VECTOR_MASK)
 117
 118 #define LINT_MASK       \
 119         (LVT_MASK | APIC_MODE_MASK | APIC_INPUT_POLARITY | \
 120          APIC_LVT_REMOTE_IRR | APIC_LVT_LEVEL_TRIGGER)
 121
 122 static inline int kvm_apic_id(struct kvm_lapic *apic)
 123 {
 124         return (apic_get_reg(apic, APIC_ID) >> 24) & 0xff;
 125 }
 126
 127 static inline int apic_lvt_enabled(struct kvm_lapic *apic, int lvt_type)
 128 {
 129         return !(apic_get_reg(apic, lvt_type) & APIC_LVT_MASKED);
 130 }
 131
 132 static inline int apic_lvt_vector(struct kvm_lapic *apic, int lvt_type)
 133 {
 134         return apic_get_reg(apic, lvt_type) & APIC_VECTOR_MASK;
 135 }
 136
 137 static inline int apic_lvtt_period(struct kvm_lapic *apic)
 138 {
 139         return apic_get_reg(apic, APIC_LVTT) & APIC_LVT_TIMER_PERIODIC;
 140 }
 141
 142 static inline int apic_lvt_nmi_mode(u32 lvt_val)
 143 {
 144         return (lvt_val & (APIC_MODE_MASK | APIC_LVT_MASKED)) == APIC_DM_NMI;
 145 }
 146
 147 void kvm_apic_set_version(struct kvm_vcpu *vcpu)
 148 {
 149         struct kvm_lapic *apic = vcpu->arch.apic;
 150         struct kvm_cpuid_entry2 *feat;
 151         u32 v = APIC_VERSION;
 152
 153         if (!irqchip_in_kernel(vcpu->kvm))
 154                 return;
 155
 156         feat = kvm_find_cpuid_entry(apic->vcpu, 0x1, 0);
 157         if (feat && (feat->ecx & (1 << (X86_FEATURE_X2APIC & 31))))
 158                 v |= APIC_LVR_DIRECTED_EOI;
 159         apic_set_reg(apic, APIC_LVR, v);
 160 }
 161
 162 static inline int apic_x2apic_mode(struct kvm_lapic *apic)
 163 {
 164         return apic->vcpu->arch.apic_base & X2APIC_ENABLE;
 165 }
 166
 167 static unsigned int apic_lvt_mask[APIC_LVT_NUM] = {
 168         LVT_MASK | APIC_LVT_TIMER_PERIODIC,     /* LVTT */
 169         LVT_MASK | APIC_MODE_MASK,      /* LVTTHMR */
 170         LVT_MASK | APIC_MODE_MASK,      /* LVTPC */
 171         LINT_MASK, LINT_MASK,   /* LVT0-1 */
 172         LVT_MASK                /* LVTERR */
 173 };
 174
 175 static int find_highest_vector(void *bitmap)
 176 {
 177         u32 *word = bitmap;
 178         int word_offset = MAX_APIC_VECTOR >> 5;
 179
 180         while ((word_offset != 0) && (word[(--word_offset) << 2] == 0))
 181                 continue;
 182
 183         if (likely(!word_offset && !word[0]))
 184                 return -1;
 185         else
 186                 return fls(word[word_offset << 2]) - 1 + (word_offset << 5);
 187 }
 188
 189 static inline int apic_test_and_set_irr(int vec, struct kvm_lapic *apic)
 190 {
 191         apic->irr_pending = true;
 192         return apic_test_and_set_vector(vec, apic->regs + APIC_IRR);
 193 }
 194
 195 static inline int apic_search_irr(struct kvm_lapic *apic)
 196 {
 197         return find_highest_vector(apic->regs + APIC_IRR);
 198 }
 199
 200 static inline int apic_find_highest_irr(struct kvm_lapic *apic)
 201 {
 202         int result;
 203
 204         if (!apic->irr_pending)
 205                 return -1;
 206
 207         result = apic_search_irr(apic);
 208         ASSERT(result == -1 || result >= 16);
 209
 210         return result;
 211 }
 212
 213 static inline void apic_clear_irr(int vec, struct kvm_lapic *apic)
 214 {
 215         apic->irr_pending = false;
 216         apic_clear_vector(vec, apic->regs + APIC_IRR);
 217         if (apic_search_irr(apic) != -1)
 218                 apic->irr_pending = true;
 219 }
 220
 221 int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu)
 222 {
 223         struct kvm_lapic *apic = vcpu->arch.apic;
 224         int highest_irr;
 225
 226         /* This may race with setting of irr in __apic_accept_irq() and
 227          * value returned may be wrong, but kvm_vcpu_kick() in __apic_accept_irq
 228          * will cause vmexit immediately and the value will be recalculated
 229          * on the next vmentry.
 230          */
 231         if (!apic)
 232                 return 0;
 233         highest_irr = apic_find_highest_irr(apic);
 234
 235         return highest_irr;
 236 }
 237
 238 static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
 239                              int vector, int level, int trig_mode);
 240
 241 int kvm_apic_set_irq(struct kvm_vcpu *vcpu, struct kvm_lapic_irq *irq)
 242 {
 243         struct kvm_lapic *apic = vcpu->arch.apic;
 244
 245         return __apic_accept_irq(apic, irq->delivery_mode, irq->vector,
 246                         irq->level, irq->trig_mode);
 247 }
 248
 249 static inline int apic_find_highest_isr(struct kvm_lapic *apic)
 250 {
 251         int result;
 252
 253         result = find_highest_vector(apic->regs + APIC_ISR);
 254         ASSERT(result == -1 || result >= 16);
 255
 256         return result;
 257 }
 258
 259 static void apic_update_ppr(struct kvm_lapic *apic)
 260 {
 261         u32 tpr, isrv, ppr;
 262         int isr;
 263
 264         tpr = apic_get_reg(apic, APIC_TASKPRI);
 265         isr = apic_find_highest_isr(apic);
 266         isrv = (isr != -1) ? isr : 0;
 267
 268         if ((tpr & 0xf0) >= (isrv & 0xf0))
 269                 ppr = tpr & 0xff;
 270         else
 271                 ppr = isrv & 0xf0;
 272
 273         apic_debug("vlapic %p, ppr 0x%x, isr 0x%x, isrv 0x%x",
 274                    apic, ppr, isr, isrv);
 275
 276         apic_set_reg(apic, APIC_PROCPRI, ppr);
 277 }
 278
 279 static void apic_set_tpr(struct kvm_lapic *apic, u32 tpr)
 280 {
 281         apic_set_reg(apic, APIC_TASKPRI, tpr);
 282         apic_update_ppr(apic);
 283 }
 284
 285 int kvm_apic_match_physical_addr(struct kvm_lapic *apic, u16 dest)
 286 {
 287         return dest == 0xff || kvm_apic_id(apic) == dest;
 288 }
 289
 290 int kvm_apic_match_logical_addr(struct kvm_lapic *apic, u8 mda)
 291 {
 292         int result = 0;
 293         u32 logical_id;
 294
 295         if (apic_x2apic_mode(apic)) {
 296                 logical_id = apic_get_reg(apic, APIC_LDR);
 297                 return logical_id & mda;
 298         }
 299
 300         logical_id = GET_APIC_LOGICAL_ID(apic_get_reg(apic, APIC_LDR));
 301
 302         switch (apic_get_reg(apic, APIC_DFR)) {
 303         case APIC_DFR_FLAT:
 304                 if (logical_id & mda)
 305                         result = 1;
 306                 break;
 307         case APIC_DFR_CLUSTER:
 308                 if (((logical_id >> 4) == (mda >> 0x4))
 309                     && (logical_id & mda & 0xf))
 310                         result = 1;
 311                 break;
 312         default:
 313                 printk(KERN_WARNING "Bad DFR vcpu %d: %08x\n",
 314                        apic->vcpu->vcpu_id, apic_get_reg(apic, APIC_DFR));
 315                 break;
 316         }
 317
 318         return result;
 319 }
 320
 321 int kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source,
 322                            int short_hand, int dest, int dest_mode)
 323 {
 324         int result = 0;
 325         struct kvm_lapic *target = vcpu->arch.apic;
 326
 327         apic_debug("target %p, source %p, dest 0x%x, "
 328                    "dest_mode 0x%x, short_hand 0x%x\n",
 329                    target, source, dest, dest_mode, short_hand);
 330
 331         ASSERT(!target);
 332         switch (short_hand) {
 333         case APIC_DEST_NOSHORT:
 334                 if (dest_mode == 0)
 335                         /* Physical mode. */
 336                         result = kvm_apic_match_physical_addr(target, dest);
 337                 else
 338                         /* Logical mode. */
 339                         result = kvm_apic_match_logical_addr(target, dest);
 340                 break;
 341         case APIC_DEST_SELF:
 342                 result = (target == source);
 343                 break;
 344         case APIC_DEST_ALLINC:
 345                 result = 1;
 346                 break;
 347         case APIC_DEST_ALLBUT:
 348                 result = (target != source);
 349                 break;
 350         default:
 351                 printk(KERN_WARNING "Bad dest shorthand value %x\n",
 352                        short_hand);
 353                 break;
 354         }
 355
 356         return result;
 357 }
 358
 359 /*
 360  * Add a pending IRQ into lapic.
 361  * Return 1 if successfully added and 0 if discarded.
 362  */
 363 static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
 364                              int vector, int level, int trig_mode)
 365 {
 366         int result = 0;
 367         struct kvm_vcpu *vcpu = apic->vcpu;
 368
 369         switch (delivery_mode) {
 370         case APIC_DM_LOWEST:
 371                 vcpu->arch.apic_arb_prio++;
 372         case APIC_DM_FIXED:
 373                 /* FIXME add logic for vcpu on reset */
 374                 if (unlikely(!apic_enabled(apic)))
 375                         break;
 376
 377                 result = !apic_test_and_set_irr(vector, apic);
 378                 trace_kvm_apic_accept_irq(vcpu->vcpu_id, delivery_mode,
 379                                           trig_mode, vector, !result);
 380                 if (!result) {
 381                         if (trig_mode)
 382                                 apic_debug("level trig mode repeatedly for "
 383                                                 "vector %d", vector);
 384                         break;
 385                 }
 386
 387                 if (trig_mode) {
 388                         apic_debug("level trig mode for vector %d", vector);
 389                         apic_set_vector(vector, apic->regs + APIC_TMR);
 390                 } else
 391                         apic_clear_vector(vector, apic->regs + APIC_TMR);
 392                 kvm_vcpu_kick(vcpu);
 393                 break;
 394
 395         case APIC_DM_REMRD:
 396                 printk(KERN_DEBUG "Ignoring delivery mode 3\n");
 397                 break;
 398
 399         case APIC_DM_SMI:
 400                 printk(KERN_DEBUG "Ignoring guest SMI\n");
 401                 break;
 402
 403         case APIC_DM_NMI:
 404                 result = 1;
 405                 kvm_inject_nmi(vcpu);
 406                 kvm_vcpu_kick(vcpu);
 407                 break;
 408
 409         case APIC_DM_INIT:
 410                 if (level) {
 411                         result = 1;
 412                         if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE)
 413                                 printk(KERN_DEBUG
 414                                        "INIT on a runnable vcpu %d\n",
 415                                        vcpu->vcpu_id);
 416                         vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED;
 417                         kvm_vcpu_kick(vcpu);
 418                 } else {
 419                         apic_debug("Ignoring de-assert INIT to vcpu %d\n",
 420                                    vcpu->vcpu_id);
 421                 }
 422                 break;
 423
 424         case APIC_DM_STARTUP:
 425                 apic_debug("SIPI to vcpu %d vector 0x%02x\n",
 426                            vcpu->vcpu_id, vector);
 427                 if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) {
 428                         result = 1;
 429                         vcpu->arch.sipi_vector = vector;
 430                         vcpu->arch.mp_state = KVM_MP_STATE_SIPI_RECEIVED;
 431                         kvm_vcpu_kick(vcpu);
 432                 }
 433                 break;
 434
 435         case APIC_DM_EXTINT:
 436                 /*
 437                  * Should only be called by kvm_apic_local_deliver() with LVT0,
 438                  * before NMI watchdog was enabled. Already handled by
 439                  * kvm_apic_accept_pic_intr().
 440                  */
 441                 break;
 442
 443         default:
 444                 printk(KERN_ERR "TODO: unsupported delivery mode %x\n",
 445                        delivery_mode);
 446                 break;
 447         }
 448         return result;
 449 }
 450
 451 int kvm_apic_compare_prio(struct kvm_vcpu *vcpu1, struct kvm_vcpu *vcpu2)
 452 {
 453         return vcpu1->arch.apic_arb_prio - vcpu2->arch.apic_arb_prio;
 454 }
 455
 456 static void apic_set_eoi(struct kvm_lapic *apic)
 457 {
 458         int vector = apic_find_highest_isr(apic);
 459         int trigger_mode;
 460         /*
 461          * Not every write EOI will has corresponding ISR,
 462          * one example is when Kernel check timer on setup_IO_APIC
 463          */
 464         if (vector == -1)
 465                 return;
 466
 467         apic_clear_vector(vector, apic->regs + APIC_ISR);
 468         apic_update_ppr(apic);
 469
 470         if (apic_test_and_clear_vector(vector, apic->regs + APIC_TMR))
 471                 trigger_mode = IOAPIC_LEVEL_TRIG;
 472         else
 473                 trigger_mode = IOAPIC_EDGE_TRIG;
 474         if (!(apic_get_reg(apic, APIC_SPIV) & APIC_SPIV_DIRECTED_EOI))
 475                 kvm_ioapic_update_eoi(apic->vcpu->kvm, vector, trigger_mode);
 476 }
 477
 478 static void apic_send_ipi(struct kvm_lapic *apic)
 479 {
 480         u32 icr_low = apic_get_reg(apic, APIC_ICR);
 481         u32 icr_high = apic_get_reg(apic, APIC_ICR2);
 482         struct kvm_lapic_irq irq;
 483
 484         irq.vector = icr_low & APIC_VECTOR_MASK;
 485         irq.delivery_mode = icr_low & APIC_MODE_MASK;
 486         irq.dest_mode = icr_low & APIC_DEST_MASK;
 487         irq.level = icr_low & APIC_INT_ASSERT;
 488         irq.trig_mode = icr_low & APIC_INT_LEVELTRIG;
 489         irq.shorthand = icr_low & APIC_SHORT_MASK;
 490         if (apic_x2apic_mode(apic))
 491                 irq.dest_id = icr_high;
 492         else
 493                 irq.dest_id = GET_APIC_DEST_FIELD(icr_high);
 494
 495         trace_kvm_apic_ipi(icr_low, irq.dest_id);
 496
 497         apic_debug("icr_high 0x%x, icr_low 0x%x, "
 498                    "short_hand 0x%x, dest 0x%x, trig_mode 0x%x, level 0x%x, "
 499                    "dest_mode 0x%x, delivery_mode 0x%x, vector 0x%x\n",
 500                    icr_high, icr_low, irq.shorthand, irq.dest_id,
 501                    irq.trig_mode, irq.level, irq.dest_mode, irq.delivery_mode,
 502                    irq.vector);
 503
 504         mutex_lock(&apic->vcpu->kvm->irq_lock);
 505         kvm_irq_delivery_to_apic(apic->vcpu->kvm, apic, &irq);
 506         mutex_unlock(&apic->vcpu->kvm->irq_lock);
 507 }
 508
 509 static u32 apic_get_tmcct(struct kvm_lapic *apic)
 510 {
 511         ktime_t remaining;
 512         s64 ns;
 513         u32 tmcct;
 514
 515         ASSERT(apic != NULL);
 516
 517         /* if initial count is 0, current count should also be 0 */
 518         if (apic_get_reg(apic, APIC_TMICT) == 0)
 519                 return 0;
 520
 521         remaining = hrtimer_get_remaining(&apic->lapic_timer.timer);
 522         if (ktime_to_ns(remaining) < 0)
 523                 remaining = ktime_set(0, 0);
 524
 525         ns = mod_64(ktime_to_ns(remaining), apic->lapic_timer.period);
 526         tmcct = div64_u64(ns,
 527                          (APIC_BUS_CYCLE_NS * apic->divide_count));
 528
 529         return tmcct;
 530 }
 531
 532 static void __report_tpr_access(struct kvm_lapic *apic, bool write)
 533 {
 534         struct kvm_vcpu *vcpu = apic->vcpu;
 535         struct kvm_run *run = vcpu->run;
 536
 537         set_bit(KVM_REQ_REPORT_TPR_ACCESS, &vcpu->requests);
 538         run->tpr_access.rip = kvm_rip_read(vcpu);
 539         run->tpr_access.is_write = write;
 540 }
 541
 542 static inline void report_tpr_access(struct kvm_lapic *apic, bool write)
 543 {
 544         if (apic->vcpu->arch.tpr_access_reporting)
 545                 __report_tpr_access(apic, write);
 546 }
 547
 548 static u32 __apic_read(struct kvm_lapic *apic, unsigned int offset)
 549 {
 550         u32 val = 0;
 551
 552         if (offset >= LAPIC_MMIO_LENGTH)
 553                 return 0;
 554
 555         switch (offset) {
 556         case APIC_ID:
 557                 if (apic_x2apic_mode(apic))
 558                         val = kvm_apic_id(apic);
 559                 else
 560                         val = kvm_apic_id(apic) << 24;
 561                 break;
 562         case APIC_ARBPRI:
 563                 printk(KERN_WARNING "Access APIC ARBPRI register "
 564                        "which is for P6\n");
 565                 break;
 566
 567         case APIC_TMCCT:        /* Timer CCR */
 568                 val = apic_get_tmcct(apic);
 569                 break;
 570
 571         case APIC_TASKPRI:
 572                 report_tpr_access(apic, false);
 573                 /* fall thru */
 574         default:
 575                 apic_update_ppr(apic);
 576                 val = apic_get_reg(apic, offset);
 577                 break;
 578         }
 579
 580         return val;
 581 }
 582
 583 static inline struct kvm_lapic *to_lapic(struct kvm_io_device *dev)
 584 {
 585         return container_of(dev, struct kvm_lapic, dev);
 586 }
 587
 588 static int apic_reg_read(struct kvm_lapic *apic, u32 offset, int len,
 589                 void *data)
 590 {
 591         unsigned char alignment = offset & 0xf;
 592         u32 result;
 593         /* this bitmask has a bit cleared for each reserver register */
 594         static const u64 rmask = 0x43ff01ffffffe70cULL;
 595
 596         if ((alignment + len) > 4) {
 597                 apic_debug("KVM_APIC_READ: alignment error %x %d\n",
 598                            offset, len);
 599                 return 1;
 600         }
 601
 602         if (offset > 0x3f0 || !(rmask & (1ULL << (offset >> 4)))) {
 603                 apic_debug("KVM_APIC_READ: read reserved register %x\n",
 604                            offset);
 605                 return 1;
 606         }
 607
 608         result = __apic_read(apic, offset & ~0xf);
 609
 610         trace_kvm_apic_read(offset, result);
 611
 612         switch (len) {
 613         case 1:
 614         case 2:
 615         case 4:
 616                 memcpy(data, (char *)&result + alignment, len);
 617                 break;
 618         default:
 619                 printk(KERN_ERR "Local APIC read with len = %x, "
 620                        "should be 1,2, or 4 instead\n", len);
 621                 break;
 622         }
 623         return 0;
 624 }
 625
 626 static int apic_mmio_in_range(struct kvm_lapic *apic, gpa_t addr)
 627 {
 628         return apic_hw_enabled(apic) &&
 629             addr >= apic->base_address &&
 630             addr < apic->base_address + LAPIC_MMIO_LENGTH;
 631 }
 632
 633 static int apic_mmio_read(struct kvm_io_device *this,
 634                            gpa_t address, int len, void *data)
 635 {
 636         struct kvm_lapic *apic = to_lapic(this);
 637         u32 offset = address - apic->base_address;
 638
 639         if (!apic_mmio_in_range(apic, address))
 640                 return -EOPNOTSUPP;
 641
 642         apic_reg_read(apic, offset, len, data);
 643
 644         return 0;
 645 }
 646
 647 static void update_divide_count(struct kvm_lapic *apic)
 648 {
 649         u32 tmp1, tmp2, tdcr;
 650
 651         tdcr = apic_get_reg(apic, APIC_TDCR);
 652         tmp1 = tdcr & 0xf;
 653         tmp2 = ((tmp1 & 0x3) | ((tmp1 & 0x8) >> 1)) + 1;
 654         apic->divide_count = 0x1 << (tmp2 & 0x7);
 655
 656         apic_debug("timer divide count is 0x%x\n",
 657                                    apic->divide_count);
 658 }
 659
 660 static void start_apic_timer(struct kvm_lapic *apic)
 661 {
 662         ktime_t now = apic->lapic_timer.timer.base->get_time();
 663
 664         apic->lapic_timer.period = (u64)apic_get_reg(apic, APIC_TMICT) *
 665                     APIC_BUS_CYCLE_NS * apic->divide_count;
 666         atomic_set(&apic->lapic_timer.pending, 0);
 667
 668         if (!apic->lapic_timer.period)
 669                 return;
 670         /*
 671          * Do not allow the guest to program periodic timers with small
 672          * interval, since the hrtimers are not throttled by the host
 673          * scheduler.
 674          */
 675         if (apic_lvtt_period(apic)) {
 676                 if (apic->lapic_timer.period < NSEC_PER_MSEC/2)
 677                         apic->lapic_timer.period = NSEC_PER_MSEC/2;
 678         }
 679
 680         hrtimer_start(&apic->lapic_timer.timer,
 681                       ktime_add_ns(now, apic->lapic_timer.period),
 682                       HRTIMER_MODE_ABS);
 683
 684         apic_debug("%s: bus cycle is %" PRId64 "ns, now 0x%016"
 685                            PRIx64 ", "
 686                            "timer initial count 0x%x, period %lldns, "
 687                            "expire @ 0x%016" PRIx64 ".\n", __func__,
 688                            APIC_BUS_CYCLE_NS, ktime_to_ns(now),
 689                            apic_get_reg(apic, APIC_TMICT),
 690                            apic->lapic_timer.period,
 691                            ktime_to_ns(ktime_add_ns(now,
 692                                         apic->lapic_timer.period)));
 693 }
 694
 695 static void apic_manage_nmi_watchdog(struct kvm_lapic *apic, u32 lvt0_val)
 696 {
 697         int nmi_wd_enabled = apic_lvt_nmi_mode(apic_get_reg(apic, APIC_LVT0));
 698
 699         if (apic_lvt_nmi_mode(lvt0_val)) {
 700                 if (!nmi_wd_enabled) {
 701                         apic_debug("Receive NMI setting on APIC_LVT0 "
 702                                    "for cpu %d\n", apic->vcpu->vcpu_id);
 703                         apic->vcpu->kvm->arch.vapics_in_nmi_mode++;
 704                 }
 705         } else if (nmi_wd_enabled)
 706                 apic->vcpu->kvm->arch.vapics_in_nmi_mode--;
 707 }
 708
 709 static int apic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
 710 {
 711         int ret = 0;
 712
 713         trace_kvm_apic_write(reg, val);
 714
 715         switch (reg) {
 716         case APIC_ID:           /* Local APIC ID */
 717                 if (!apic_x2apic_mode(apic))
 718                         apic_set_reg(apic, APIC_ID, val);
 719                 else
 720                         ret = 1;
 721                 break;
 722
 723         case APIC_TASKPRI:
 724                 report_tpr_access(apic, true);
 725                 apic_set_tpr(apic, val & 0xff);
 726                 break;
 727
 728         case APIC_EOI:
 729                 apic_set_eoi(apic);
 730                 break;
 731
 732         case APIC_LDR:
 733                 if (!apic_x2apic_mode(apic))
 734                         apic_set_reg(apic, APIC_LDR, val & APIC_LDR_MASK);
 735                 else
 736                         ret = 1;
 737                 break;
 738
 739         case APIC_DFR:
 740                 if (!apic_x2apic_mode(apic))
 741                         apic_set_reg(apic, APIC_DFR, val | 0x0FFFFFFF);
 742                 else
 743                         ret = 1;
 744                 break;
 745
 746         case APIC_SPIV: {
 747                 u32 mask = 0x3ff;
 748                 if (apic_get_reg(apic, APIC_LVR) & APIC_LVR_DIRECTED_EOI)
 749                         mask |= APIC_SPIV_DIRECTED_EOI;
 750                 apic_set_reg(apic, APIC_SPIV, val & mask);
 751                 if (!(val & APIC_SPIV_APIC_ENABLED)) {
 752                         int i;
 753                         u32 lvt_val;
 754
 755                         for (i = 0; i < APIC_LVT_NUM; i++) {
 756                                 lvt_val = apic_get_reg(apic,
 757                                                        APIC_LVTT + 0x10 * i);
 758                                 apic_set_reg(apic, APIC_LVTT + 0x10 * i,
 759                                              lvt_val | APIC_LVT_MASKED);
 760                         }
 761                         atomic_set(&apic->lapic_timer.pending, 0);
 762
 763                 }
 764                 break;
 765         }
 766         case APIC_ICR:
 767                 /* No delay here, so we always clear the pending bit */
 768                 apic_set_reg(apic, APIC_ICR, val & ~(1 << 12));
 769                 apic_send_ipi(apic);
 770                 break;
 771
 772         case APIC_ICR2:
 773                 if (!apic_x2apic_mode(apic))
 774                         val &= 0xff000000;
 775                 apic_set_reg(apic, APIC_ICR2, val);
 776                 break;
 777
 778         case APIC_LVT0:
 779                 apic_manage_nmi_watchdog(apic, val);
 780         case APIC_LVTT:
 781         case APIC_LVTTHMR:
 782         case APIC_LVTPC:
 783         case APIC_LVT1:
 784         case APIC_LVTERR:
 785                 /* TODO: Check vector */
 786                 if (!apic_sw_enabled(apic))
 787                         val |= APIC_LVT_MASKED;
 788
 789                 val &= apic_lvt_mask[(reg - APIC_LVTT) >> 4];
 790                 apic_set_reg(apic, reg, val);
 791
 792                 break;
 793
 794         case APIC_TMICT:
 795                 hrtimer_cancel(&apic->lapic_timer.timer);
 796                 apic_set_reg(apic, APIC_TMICT, val);
 797                 start_apic_timer(apic);
 798                 break;
 799
 800         case APIC_TDCR:
 801                 if (val & 4)
 802                         printk(KERN_ERR "KVM_WRITE:TDCR %x\n", val);
 803                 apic_set_reg(apic, APIC_TDCR, val);
 804                 update_divide_count(apic);
 805                 break;
 806
 807         case APIC_ESR:
 808                 if (apic_x2apic_mode(apic) && val != 0) {
 809                         printk(KERN_ERR "KVM_WRITE:ESR not zero %x\n", val);
 810                         ret = 1;
 811                 }
 812                 break;
 813
 814         case APIC_SELF_IPI:
 815                 if (apic_x2apic_mode(apic)) {
 816                         apic_reg_write(apic, APIC_ICR, 0x40000 | (val & 0xff));
 817                 } else
 818                         ret = 1;
 819                 break;
 820         default:
 821                 ret = 1;
 822                 break;
 823         }
 824         if (ret)
 825                 apic_debug("Local APIC Write to read-only register %x\n", reg);
 826         return ret;
 827 }
 828
 829 static int apic_mmio_write(struct kvm_io_device *this,
 830                             gpa_t address, int len, const void *data)
 831 {
 832         struct kvm_lapic *apic = to_lapic(this);
 833         unsigned int offset = address - apic->base_address;
 834         u32 val;
 835
 836         if (!apic_mmio_in_range(apic, address))
 837                 return -EOPNOTSUPP;
 838
 839         /*
 840          * APIC register must be aligned on 128-bits boundary.
 841          * 32/64/128 bits registers must be accessed thru 32 bits.
 842          * Refer SDM 8.4.1
 843          */
 844         if (len != 4 || (offset & 0xf)) {
 845                 /* Don't shout loud, $infamous_os would cause only noise. */
 846                 apic_debug("apic write: bad size=%d %lx\n", len, (long)address);
 847                 return 0;
 848         }
 849
 850         val = *(u32*)data;
 851
 852         /* too common printing */
 853         if (offset != APIC_EOI)
 854                 apic_debug("%s: offset 0x%x with length 0x%x, and value is "
 855                            "0x%x\n", __func__, offset, len, val);
 856
 857         apic_reg_write(apic, offset & 0xff0, val);
 858
 859         return 0;
 860 }
 861
 862 void kvm_free_lapic(struct kvm_vcpu *vcpu)
 863 {
 864         if (!vcpu->arch.apic)
 865                 return;
 866
 867         hrtimer_cancel(&vcpu->arch.apic->lapic_timer.timer);
 868
 869         if (vcpu->arch.apic->regs_page)
 870                 __free_page(vcpu->arch.apic->regs_page);
 871
 872         kfree(vcpu->arch.apic);
 873 }
 874
 875 /*
 876  *----------------------------------------------------------------------
 877  * LAPIC interface
 878  *----------------------------------------------------------------------
 879  */
 880
 881 void kvm_lapic_set_tpr(struct kvm_vcpu *vcpu, unsigned long cr8)
 882 {
 883         struct kvm_lapic *apic = vcpu->arch.apic;
 884
 885         if (!apic)
 886                 return;
 887         apic_set_tpr(apic, ((cr8 & 0x0f) << 4)
 888                      | (apic_get_reg(apic, APIC_TASKPRI) & 4));
 889 }
 890
 891 u64 kvm_lapic_get_cr8(struct kvm_vcpu *vcpu)
 892 {
 893         struct kvm_lapic *apic = vcpu->arch.apic;
 894         u64 tpr;
 895
 896         if (!apic)
 897                 return 0;
 898         tpr = (u64) apic_get_reg(apic, APIC_TASKPRI);
 899
 900         return (tpr & 0xf0) >> 4;
 901 }
 902
 903 void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value)
 904 {
 905         struct kvm_lapic *apic = vcpu->arch.apic;
 906
 907         if (!apic) {
 908                 value |= MSR_IA32_APICBASE_BSP;
 909                 vcpu->arch.apic_base = value;
 910                 return;
 911         }
 912
 913         if (!kvm_vcpu_is_bsp(apic->vcpu))
 914                 value &= ~MSR_IA32_APICBASE_BSP;
 915
 916         vcpu->arch.apic_base = value;
 917         if (apic_x2apic_mode(apic)) {
 918                 u32 id = kvm_apic_id(apic);
 919                 u32 ldr = ((id & ~0xf) << 16) | (1 << (id & 0xf));
 920                 apic_set_reg(apic, APIC_LDR, ldr);
 921         }
 922         apic->base_address = apic->vcpu->arch.apic_base &
 923                              MSR_IA32_APICBASE_BASE;
 924
 925         /* with FSB delivery interrupt, we can restart APIC functionality */
 926         apic_debug("apic base msr is 0x%016" PRIx64 ", and base address is "
 927                    "0x%lx.\n", apic->vcpu->arch.apic_base, apic->base_address);
 928
 929 }
 930
 931 void kvm_lapic_reset(struct kvm_vcpu *vcpu)
 932 {
 933         struct kvm_lapic *apic;
 934         int i;
 935
 936         apic_debug("%s\n", __func__);
 937
 938         ASSERT(vcpu);
 939         apic = vcpu->arch.apic;
 940         ASSERT(apic != NULL);
 941
 942         /* Stop the timer in case it's a reset to an active apic */
 943         hrtimer_cancel(&apic->lapic_timer.timer);
 944
 945         apic_set_reg(apic, APIC_ID, vcpu->vcpu_id << 24);
 946         kvm_apic_set_version(apic->vcpu);
 947
 948         for (i = 0; i < APIC_LVT_NUM; i++)
 949                 apic_set_reg(apic, APIC_LVTT + 0x10 * i, APIC_LVT_MASKED);
 950         apic_set_reg(apic, APIC_LVT0,
 951                      SET_APIC_DELIVERY_MODE(0, APIC_MODE_EXTINT));
 952
 953         apic_set_reg(apic, APIC_DFR, 0xffffffffU);
 954         apic_set_reg(apic, APIC_SPIV, 0xff);
 955         apic_set_reg(apic, APIC_TASKPRI, 0);
 956         apic_set_reg(apic, APIC_LDR, 0);
 957         apic_set_reg(apic, APIC_ESR, 0);
 958         apic_set_reg(apic, APIC_ICR, 0);
 959         apic_set_reg(apic, APIC_ICR2, 0);
 960         apic_set_reg(apic, APIC_TDCR, 0);
 961         apic_set_reg(apic, APIC_TMICT, 0);
 962         for (i = 0; i < 8; i++) {
 963                 apic_set_reg(apic, APIC_IRR + 0x10 * i, 0);
 964                 apic_set_reg(apic, APIC_ISR + 0x10 * i, 0);
 965                 apic_set_reg(apic, APIC_TMR + 0x10 * i, 0);
 966         }
 967         apic->irr_pending = false;
 968         update_divide_count(apic);
 969         atomic_set(&apic->lapic_timer.pending, 0);
 970         if (kvm_vcpu_is_bsp(vcpu))
 971                 vcpu->arch.apic_base |= MSR_IA32_APICBASE_BSP;
 972         apic_update_ppr(apic);
 973
 974         vcpu->arch.apic_arb_prio = 0;
 975
 976         apic_debug(KERN_INFO "%s: vcpu=%p, id=%d, base_msr="
 977                    "0x%016" PRIx64 ", base_address=0x%0lx.\n", __func__,
 978                    vcpu, kvm_apic_id(apic),
 979                    vcpu->arch.apic_base, apic->base_address);
 980 }
 981
 982 bool kvm_apic_present(struct kvm_vcpu *vcpu)
 983 {
 984         return vcpu->arch.apic && apic_hw_enabled(vcpu->arch.apic);
 985 }
 986
 987 int kvm_lapic_enabled(struct kvm_vcpu *vcpu)
 988 {
 989         return kvm_apic_present(vcpu) && apic_sw_enabled(vcpu->arch.apic);
 990 }
 991
 992 /*
 993  *----------------------------------------------------------------------
 994  * timer interface
 995  *----------------------------------------------------------------------
 996  */
 997
 998 static bool lapic_is_periodic(struct kvm_timer *ktimer)
 999 {
1000         struct kvm_lapic *apic = container_of(ktimer, struct kvm_lapic,
1001                                               lapic_timer);
1002         return apic_lvtt_period(apic);
1003 }
1004
1005 int apic_has_pending_timer(struct kvm_vcpu *vcpu)
1006 {
1007         struct kvm_lapic *lapic = vcpu->arch.apic;
1008
1009         if (lapic && apic_enabled(lapic) && apic_lvt_enabled(lapic, APIC_LVTT))
1010                 return atomic_read(&lapic->lapic_timer.pending);
1011
1012         return 0;
1013 }
1014
1015 static int kvm_apic_local_deliver(struct kvm_lapic *apic, int lvt_type)
1016 {
1017         u32 reg = apic_get_reg(apic, lvt_type);
1018         int vector, mode, trig_mode;
1019
1020         if (apic_hw_enabled(apic) && !(reg & APIC_LVT_MASKED)) {
1021                 vector = reg & APIC_VECTOR_MASK;
1022                 mode = reg & APIC_MODE_MASK;
1023                 trig_mode = reg & APIC_LVT_LEVEL_TRIGGER;
1024                 return __apic_accept_irq(apic, mode, vector, 1, trig_mode);
1025         }
1026         return 0;
1027 }
1028
1029 void kvm_apic_nmi_wd_deliver(struct kvm_vcpu *vcpu)
1030 {
1031         struct kvm_lapic *apic = vcpu->arch.apic;
1032
1033         if (apic)
1034                 kvm_apic_local_deliver(apic, APIC_LVT0);
1035 }
1036
1037 static struct kvm_timer_ops lapic_timer_ops = {
1038         .is_periodic = lapic_is_periodic,
1039 };
1040
1041 static const struct kvm_io_device_ops apic_mmio_ops = {
1042         .read     = apic_mmio_read,
1043         .write    = apic_mmio_write,
1044 };
1045
1046 int kvm_create_lapic(struct kvm_vcpu *vcpu)
1047 {
1048         struct kvm_lapic *apic;
1049
1050         ASSERT(vcpu != NULL);
1051         apic_debug("apic_init %d\n", vcpu->vcpu_id);
1052
1053         apic = kzalloc(sizeof(*apic), GFP_KERNEL);
1054         if (!apic)
1055                 goto nomem;
1056
1057         vcpu->arch.apic = apic;
1058
1059         apic->regs_page = alloc_page(GFP_KERNEL);
1060         if (apic->regs_page == NULL) {
1061                 printk(KERN_ERR "malloc apic regs error for vcpu %x\n",
1062                        vcpu->vcpu_id);
1063                 goto nomem_free_apic;
1064         }
1065         apic->regs = page_address(apic->regs_page);
1066         memset(apic->regs, 0, PAGE_SIZE);
1067         apic->vcpu = vcpu;
1068
1069         hrtimer_init(&apic->lapic_timer.timer, CLOCK_MONOTONIC,
1070                      HRTIMER_MODE_ABS);
1071         apic->lapic_timer.timer.function = kvm_timer_fn;
1072         apic->lapic_timer.t_ops = &lapic_timer_ops;
1073         apic->lapic_timer.kvm = vcpu->kvm;
1074         apic->lapic_timer.vcpu = vcpu;
1075
1076         apic->base_address = APIC_DEFAULT_PHYS_BASE;
1077         vcpu->arch.apic_base = APIC_DEFAULT_PHYS_BASE;
1078
1079         kvm_lapic_reset(vcpu);
1080         kvm_iodevice_init(&apic->dev, &apic_mmio_ops);
1081
1082         return 0;
1083 nomem_free_apic:
1084         kfree(apic);
1085 nomem:
1086         return -ENOMEM;
1087 }
1088
1089 int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu)
1090 {
1091         struct kvm_lapic *apic = vcpu->arch.apic;
1092         int highest_irr;
1093
1094         if (!apic || !apic_enabled(apic))
1095                 return -1;
1096
1097         apic_update_ppr(apic);
1098         highest_irr = apic_find_highest_irr(apic);
1099         if ((highest_irr == -1) ||
1100             ((highest_irr & 0xF0) <= apic_get_reg(apic, APIC_PROCPRI)))
1101                 return -1;
1102         return highest_irr;
1103 }
1104
1105 int kvm_apic_accept_pic_intr(struct kvm_vcpu *vcpu)
1106 {
1107         u32 lvt0 = apic_get_reg(vcpu->arch.apic, APIC_LVT0);
1108         int r = 0;
1109
1110         if (kvm_vcpu_is_bsp(vcpu)) {
1111                 if (!apic_hw_enabled(vcpu->arch.apic))
1112                         r = 1;
1113                 if ((lvt0 & APIC_LVT_MASKED) == 0 &&
1114                     GET_APIC_DELIVERY_MODE(lvt0) == APIC_MODE_EXTINT)
1115                         r = 1;
1116         }
1117         return r;
1118 }
1119
1120 void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu)
1121 {
1122         struct kvm_lapic *apic = vcpu->arch.apic;
1123
1124         if (apic && atomic_read(&apic->lapic_timer.pending) > 0) {
1125                 if (kvm_apic_local_deliver(apic, APIC_LVTT))
1126                         atomic_dec(&apic->lapic_timer.pending);
1127         }
1128 }
1129
1130 int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu)
1131 {
1132         int vector = kvm_apic_has_interrupt(vcpu);
1133         struct kvm_lapic *apic = vcpu->arch.apic;
1134
1135         if (vector == -1)
1136                 return -1;
1137
1138         apic_set_vector(vector, apic->regs + APIC_ISR);
1139         apic_update_ppr(apic);
1140         apic_clear_irr(vector, apic);
1141         return vector;
1142 }
1143
1144 void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu)
1145 {
1146         struct kvm_lapic *apic = vcpu->arch.apic;
1147
1148         apic->base_address = vcpu->arch.apic_base &
1149                              MSR_IA32_APICBASE_BASE;
1150         kvm_apic_set_version(vcpu);
1151
1152         apic_update_ppr(apic);
1153         hrtimer_cancel(&apic->lapic_timer.timer);
1154         update_divide_count(apic);
1155         start_apic_timer(apic);
1156 }
1157
1158 void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
1159 {
1160         struct kvm_lapic *apic = vcpu->arch.apic;
1161         struct hrtimer *timer;
1162
1163         if (!apic)
1164                 return;
1165
1166         timer = &apic->lapic_timer.timer;
1167         if (hrtimer_cancel(timer))
1168                 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
1169 }
1170
1171 void kvm_lapic_sync_from_vapic(struct kvm_vcpu *vcpu)
1172 {
1173         u32 data;
1174         void *vapic;
1175
1176         if (!irqchip_in_kernel(vcpu->kvm) || !vcpu->arch.apic->vapic_addr)
1177                 return;
1178
1179         vapic = kmap_atomic(vcpu->arch.apic->vapic_page, KM_USER0);
1180         data = *(u32 *)(vapic + offset_in_page(vcpu->arch.apic->vapic_addr));
1181         kunmap_atomic(vapic, KM_USER0);
1182
1183         apic_set_tpr(vcpu->arch.apic, data & 0xff);
1184 }
1185
1186 void kvm_lapic_sync_to_vapic(struct kvm_vcpu *vcpu)
1187 {
1188         u32 data, tpr;
1189         int max_irr, max_isr;
1190         struct kvm_lapic *apic;
1191         void *vapic;
1192
1193         if (!irqchip_in_kernel(vcpu->kvm) || !vcpu->arch.apic->vapic_addr)
1194                 return;
1195
1196         apic = vcpu->arch.apic;
1197         tpr = apic_get_reg(apic, APIC_TASKPRI) & 0xff;
1198         max_irr = apic_find_highest_irr(apic);
1199         if (max_irr < 0)
1200                 max_irr = 0;
1201         max_isr = apic_find_highest_isr(apic);
1202         if (max_isr < 0)
1203                 max_isr = 0;
1204         data = (tpr & 0xff) | ((max_isr & 0xf0) << 8) | (max_irr << 24);
1205
1206         vapic = kmap_atomic(vcpu->arch.apic->vapic_page, KM_USER0);
1207         *(u32 *)(vapic + offset_in_page(vcpu->arch.apic->vapic_addr)) = data;
1208         kunmap_atomic(vapic, KM_USER0);
1209 }
1210
1211 void kvm_lapic_set_vapic_addr(struct kvm_vcpu *vcpu, gpa_t vapic_addr)
1212 {
1213         if (!irqchip_in_kernel(vcpu->kvm))
1214                 return;
1215
1216         vcpu->arch.apic->vapic_addr = vapic_addr;
1217 }
1218
1219 int kvm_x2apic_msr_write(struct kvm_vcpu *vcpu, u32 msr, u64 data)
1220 {
1221         struct kvm_lapic *apic = vcpu->arch.apic;
1222         u32 reg = (msr - APIC_BASE_MSR) << 4;
1223
1224         if (!irqchip_in_kernel(vcpu->kvm) || !apic_x2apic_mode(apic))
1225                 return 1;
1226
1227         /* if this is ICR write vector before command */
1228         if (msr == 0x830)
1229                 apic_reg_write(apic, APIC_ICR2, (u32)(data >> 32));
1230         return apic_reg_write(apic, reg, (u32)data);
1231 }
1232
1233 int kvm_x2apic_msr_read(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
1234 {
1235         struct kvm_lapic *apic = vcpu->arch.apic;
1236         u32 reg = (msr - APIC_BASE_MSR) << 4, low, high = 0;
1237
1238         if (!irqchip_in_kernel(vcpu->kvm) || !apic_x2apic_mode(apic))
1239                 return 1;
1240
1241         if (apic_reg_read(apic, reg, 4, &low))
1242                 return 1;
1243         if (msr == 0x830)
1244                 apic_reg_read(apic, APIC_ICR2, 4, &high);
1245
1246         *data = (((u64)high) << 32) | low;
1247
1248         return 0;
1249 }