base.cc revision 11839
1/* 2 * Copyright (c) 2012, 2015 ARM Limited 3 * All rights reserved 4 * 5 * The license below extends only to copyright in the software and shall 6 * not be construed as granting a license to any other intellectual 7 * property including but not limited to intellectual property relating 8 * to a hardware implementation of the functionality of the software 9 * licensed hereunder. You may use the software subject to the license 10 * terms below provided that you ensure that this notice is replicated 11 * unmodified and in its entirety in all distributions of the software, 12 * modified or unmodified, in source code or in binary form. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions are 16 * met: redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer; 18 * redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution; 21 * neither the name of the copyright holders nor the names of its 22 * contributors may be used to endorse or promote products derived from 23 * this software without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 * 37 * Authors: Andreas Sandberg 38 */ 39 40#include "cpu/kvm/base.hh" 41 42#include <linux/kvm.h> 43#include <sys/ioctl.h> 44#include <sys/mman.h> 45#include <unistd.h> 46 47#include <cerrno> 48#include <csignal> 49#include <ostream> 50 51#include "arch/mmapped_ipr.hh" 52#include "arch/utility.hh" 53#include "debug/Checkpoint.hh" 54#include "debug/Drain.hh" 55#include "debug/Kvm.hh" 56#include "debug/KvmIO.hh" 57#include "debug/KvmRun.hh" 58#include "params/BaseKvmCPU.hh" 59#include "sim/process.hh" 60#include "sim/system.hh" 61 62/* Used by some KVM macros */ 63#define PAGE_SIZE pageSize 64 65BaseKvmCPU::BaseKvmCPU(BaseKvmCPUParams *params) 66 : BaseCPU(params), 67 vm(*params->system->getKvmVM()), 68 _status(Idle), 69 dataPort(name() + ".dcache_port", this), 70 instPort(name() + ".icache_port", this), 71 alwaysSyncTC(params->alwaysSyncTC), 72 threadContextDirty(true), 73 kvmStateDirty(false), 74 vcpuID(vm.allocVCPUID()), vcpuFD(-1), vcpuMMapSize(0), 75 _kvmRun(NULL), mmioRing(NULL), 76 pageSize(sysconf(_SC_PAGE_SIZE)), 77 tickEvent(*this), 78 activeInstPeriod(0), 79 perfControlledByTimer(params->usePerfOverflow), 80 hostFactor(params->hostFactor), 81 ctrInsts(0) 82{ 83 if (pageSize == -1) 84 panic("KVM: Failed to determine host page size (%i)\n", 85 errno); 86 87 if (FullSystem) 88 thread = new SimpleThread(this, 0, params->system, params->itb, params->dtb, 89 params->isa[0]); 90 else 91 thread = new SimpleThread(this, /* thread_num */ 0, params->system, 92 params->workload[0], params->itb, 93 params->dtb, params->isa[0]); 94 95 thread->setStatus(ThreadContext::Halted); 96 tc = thread->getTC(); 97 threadContexts.push_back(tc); 98} 99 100BaseKvmCPU::~BaseKvmCPU() 101{ 102 if (_kvmRun) 103 munmap(_kvmRun, vcpuMMapSize); 104 close(vcpuFD); 105} 106 107void 108BaseKvmCPU::init() 109{ 110 BaseCPU::init(); 111 112 if (numThreads != 1) 113 fatal("KVM: Multithreading not supported"); 114 115 tc->initMemProxies(tc); 116 117 // initialize CPU, including PC 118 if (FullSystem && !switchedOut()) 119 TheISA::initCPU(tc, tc->contextId()); 120} 121 122void 123BaseKvmCPU::startup() 124{ 125 const BaseKvmCPUParams * const p( 126 dynamic_cast<const BaseKvmCPUParams *>(params())); 127 128 Kvm &kvm(*vm.kvm); 129 130 BaseCPU::startup(); 131 132 assert(vcpuFD == -1); 133 134 // Tell the VM that a CPU is about to start. 135 vm.cpuStartup(); 136 137 // We can't initialize KVM CPUs in BaseKvmCPU::init() since we are 138 // not guaranteed that the parent KVM VM has initialized at that 139 // point. Initialize virtual CPUs here instead. 140 vcpuFD = vm.createVCPU(vcpuID); 141 142 // Map the KVM run structure */ 143 vcpuMMapSize = kvm.getVCPUMMapSize(); 144 _kvmRun = (struct kvm_run *)mmap(0, vcpuMMapSize, 145 PROT_READ | PROT_WRITE, MAP_SHARED, 146 vcpuFD, 0); 147 if (_kvmRun == MAP_FAILED) 148 panic("KVM: Failed to map run data structure\n"); 149 150 // Setup a pointer to the MMIO ring buffer if coalesced MMIO is 151 // available. The offset into the KVM's communication page is 152 // provided by the coalesced MMIO capability. 153 int mmioOffset(kvm.capCoalescedMMIO()); 154 if (!p->useCoalescedMMIO) { 155 inform("KVM: Coalesced MMIO disabled by config.\n"); 156 } else if (mmioOffset) { 157 inform("KVM: Coalesced IO available\n"); 158 mmioRing = (struct kvm_coalesced_mmio_ring *)( 159 (char *)_kvmRun + (mmioOffset * pageSize)); 160 } else { 161 inform("KVM: Coalesced not supported by host OS\n"); 162 } 163 164 thread->startup(); 165 166 Event *startupEvent( 167 new EventWrapper<BaseKvmCPU, 168 &BaseKvmCPU::startupThread>(this, true)); 169 schedule(startupEvent, curTick()); 170} 171 172BaseKvmCPU::Status 173BaseKvmCPU::KVMCpuPort::nextIOState() const 174{ 175 return (activeMMIOReqs || pendingMMIOPkts.size()) 176 ? RunningMMIOPending : RunningServiceCompletion; 177} 178 179Tick 180BaseKvmCPU::KVMCpuPort::submitIO(PacketPtr pkt) 181{ 182 if (cpu->system->isAtomicMode()) { 183 Tick delay = sendAtomic(pkt); 184 delete pkt->req; 185 delete pkt; 186 return delay; 187 } else { 188 if (pendingMMIOPkts.empty() && sendTimingReq(pkt)) { 189 activeMMIOReqs++; 190 } else { 191 pendingMMIOPkts.push(pkt); 192 } 193 // Return value is irrelevant for timing-mode accesses. 194 return 0; 195 } 196} 197 198bool 199BaseKvmCPU::KVMCpuPort::recvTimingResp(PacketPtr pkt) 200{ 201 DPRINTF(KvmIO, "KVM: Finished timing request\n"); 202 203 delete pkt->req; 204 delete pkt; 205 activeMMIOReqs--; 206 207 // We can switch back into KVM when all pending and in-flight MMIO 208 // operations have completed. 209 if (!(activeMMIOReqs || pendingMMIOPkts.size())) { 210 DPRINTF(KvmIO, "KVM: Finished all outstanding timing requests\n"); 211 cpu->finishMMIOPending(); 212 } 213 return true; 214} 215 216void 217BaseKvmCPU::KVMCpuPort::recvReqRetry() 218{ 219 DPRINTF(KvmIO, "KVM: Retry for timing request\n"); 220 221 assert(pendingMMIOPkts.size()); 222 223 // Assuming that we can issue infinite requests this cycle is a bit 224 // unrealistic, but it's not worth modeling something more complex in 225 // KVM. 226 while (pendingMMIOPkts.size() && sendTimingReq(pendingMMIOPkts.front())) { 227 pendingMMIOPkts.pop(); 228 activeMMIOReqs++; 229 } 230} 231 232void 233BaseKvmCPU::finishMMIOPending() 234{ 235 assert(_status = RunningMMIOPending); 236 assert(!tickEvent.scheduled()); 237 238 _status = RunningServiceCompletion; 239 schedule(tickEvent, nextCycle()); 240} 241 242void 243BaseKvmCPU::startupThread() 244{ 245 // Do thread-specific initialization. We need to setup signal 246 // delivery for counters and timers from within the thread that 247 // will execute the event queue to ensure that signals are 248 // delivered to the right threads. 249 const BaseKvmCPUParams * const p( 250 dynamic_cast<const BaseKvmCPUParams *>(params())); 251 252 vcpuThread = pthread_self(); 253 254 // Setup signal handlers. This has to be done after the vCPU is 255 // created since it manipulates the vCPU signal mask. 256 setupSignalHandler(); 257 258 setupCounters(); 259 260 if (p->usePerfOverflow) 261 runTimer.reset(new PerfKvmTimer(hwCycles, 262 KVM_KICK_SIGNAL, 263 p->hostFactor, 264 p->hostFreq)); 265 else 266 runTimer.reset(new PosixKvmTimer(KVM_KICK_SIGNAL, CLOCK_MONOTONIC, 267 p->hostFactor, 268 p->hostFreq)); 269 270} 271 272void 273BaseKvmCPU::regStats() 274{ 275 using namespace Stats; 276 277 BaseCPU::regStats(); 278 279 numInsts 280 .name(name() + ".committedInsts") 281 .desc("Number of instructions committed") 282 ; 283 284 numVMExits 285 .name(name() + ".numVMExits") 286 .desc("total number of KVM exits") 287 ; 288 289 numVMHalfEntries 290 .name(name() + ".numVMHalfEntries") 291 .desc("number of KVM entries to finalize pending operations") 292 ; 293 294 numExitSignal 295 .name(name() + ".numExitSignal") 296 .desc("exits due to signal delivery") 297 ; 298 299 numMMIO 300 .name(name() + ".numMMIO") 301 .desc("number of VM exits due to memory mapped IO") 302 ; 303 304 numCoalescedMMIO 305 .name(name() + ".numCoalescedMMIO") 306 .desc("number of coalesced memory mapped IO requests") 307 ; 308 309 numIO 310 .name(name() + ".numIO") 311 .desc("number of VM exits due to legacy IO") 312 ; 313 314 numHalt 315 .name(name() + ".numHalt") 316 .desc("number of VM exits due to wait for interrupt instructions") 317 ; 318 319 numInterrupts 320 .name(name() + ".numInterrupts") 321 .desc("number of interrupts delivered") 322 ; 323 324 numHypercalls 325 .name(name() + ".numHypercalls") 326 .desc("number of hypercalls") 327 ; 328} 329 330void 331BaseKvmCPU::serializeThread(CheckpointOut &cp, ThreadID tid) const 332{ 333 if (DTRACE(Checkpoint)) { 334 DPRINTF(Checkpoint, "KVM: Serializing thread %i:\n", tid); 335 dump(); 336 } 337 338 assert(tid == 0); 339 assert(_status == Idle); 340 thread->serialize(cp); 341} 342 343void 344BaseKvmCPU::unserializeThread(CheckpointIn &cp, ThreadID tid) 345{ 346 DPRINTF(Checkpoint, "KVM: Unserialize thread %i:\n", tid); 347 348 assert(tid == 0); 349 assert(_status == Idle); 350 thread->unserialize(cp); 351 threadContextDirty = true; 352} 353 354DrainState 355BaseKvmCPU::drain() 356{ 357 if (switchedOut()) 358 return DrainState::Drained; 359 360 DPRINTF(Drain, "BaseKvmCPU::drain\n"); 361 switch (_status) { 362 case Running: 363 // The base KVM code is normally ready when it is in the 364 // Running state, but the architecture specific code might be 365 // of a different opinion. This may happen when the CPU been 366 // notified of an event that hasn't been accepted by the vCPU 367 // yet. 368 if (!archIsDrained()) 369 return DrainState::Draining; 370 371 // The state of the CPU is consistent, so we don't need to do 372 // anything special to drain it. We simply de-schedule the 373 // tick event and enter the Idle state to prevent nasty things 374 // like MMIOs from happening. 375 if (tickEvent.scheduled()) 376 deschedule(tickEvent); 377 _status = Idle; 378 379 /** FALLTHROUGH */ 380 case Idle: 381 // Idle, no need to drain 382 assert(!tickEvent.scheduled()); 383 384 // Sync the thread context here since we'll need it when we 385 // switch CPUs or checkpoint the CPU. 386 syncThreadContext(); 387 388 return DrainState::Drained; 389 390 case RunningServiceCompletion: 391 // The CPU has just requested a service that was handled in 392 // the RunningService state, but the results have still not 393 // been reported to the CPU. Now, we /could/ probably just 394 // update the register state ourselves instead of letting KVM 395 // handle it, but that would be tricky. Instead, we enter KVM 396 // and let it do its stuff. 397 DPRINTF(Drain, "KVM CPU is waiting for service completion, " 398 "requesting drain.\n"); 399 return DrainState::Draining; 400 401 case RunningMMIOPending: 402 // We need to drain since there are in-flight timing accesses 403 DPRINTF(Drain, "KVM CPU is waiting for timing accesses to complete, " 404 "requesting drain.\n"); 405 return DrainState::Draining; 406 407 case RunningService: 408 // We need to drain since the CPU is waiting for service (e.g., MMIOs) 409 DPRINTF(Drain, "KVM CPU is waiting for service, requesting drain.\n"); 410 return DrainState::Draining; 411 412 default: 413 panic("KVM: Unhandled CPU state in drain()\n"); 414 return DrainState::Drained; 415 } 416} 417 418void 419BaseKvmCPU::drainResume() 420{ 421 assert(!tickEvent.scheduled()); 422 423 // We might have been switched out. In that case, we don't need to 424 // do anything. 425 if (switchedOut()) 426 return; 427 428 DPRINTF(Kvm, "drainResume\n"); 429 verifyMemoryMode(); 430 431 // The tick event is de-scheduled as a part of the draining 432 // process. Re-schedule it if the thread context is active. 433 if (tc->status() == ThreadContext::Active) { 434 schedule(tickEvent, nextCycle()); 435 _status = Running; 436 } else { 437 _status = Idle; 438 } 439} 440 441void 442BaseKvmCPU::notifyFork() 443{ 444 // We should have drained prior to forking, which means that the 445 // tick event shouldn't be scheduled and the CPU is idle. 446 assert(!tickEvent.scheduled()); 447 assert(_status == Idle); 448 449 if (vcpuFD != -1) { 450 if (close(vcpuFD) == -1) 451 warn("kvm CPU: notifyFork failed to close vcpuFD\n"); 452 453 if (_kvmRun) 454 munmap(_kvmRun, vcpuMMapSize); 455 456 vcpuFD = -1; 457 _kvmRun = NULL; 458 459 hwInstructions.detach(); 460 hwCycles.detach(); 461 } 462} 463 464void 465BaseKvmCPU::switchOut() 466{ 467 DPRINTF(Kvm, "switchOut\n"); 468 469 BaseCPU::switchOut(); 470 471 // We should have drained prior to executing a switchOut, which 472 // means that the tick event shouldn't be scheduled and the CPU is 473 // idle. 474 assert(!tickEvent.scheduled()); 475 assert(_status == Idle); 476} 477 478void 479BaseKvmCPU::takeOverFrom(BaseCPU *cpu) 480{ 481 DPRINTF(Kvm, "takeOverFrom\n"); 482 483 BaseCPU::takeOverFrom(cpu); 484 485 // We should have drained prior to executing a switchOut, which 486 // means that the tick event shouldn't be scheduled and the CPU is 487 // idle. 488 assert(!tickEvent.scheduled()); 489 assert(_status == Idle); 490 assert(threadContexts.size() == 1); 491 492 // Force an update of the KVM state here instead of flagging the 493 // TC as dirty. This is not ideal from a performance point of 494 // view, but it makes debugging easier as it allows meaningful KVM 495 // state to be dumped before and after a takeover. 496 updateKvmState(); 497 threadContextDirty = false; 498} 499 500void 501BaseKvmCPU::verifyMemoryMode() const 502{ 503 if (!(system->bypassCaches())) { 504 fatal("The KVM-based CPUs requires the memory system to be in the " 505 "'noncaching' mode.\n"); 506 } 507} 508 509void 510BaseKvmCPU::wakeup(ThreadID tid) 511{ 512 DPRINTF(Kvm, "wakeup()\n"); 513 // This method might have been called from another 514 // context. Migrate to this SimObject's event queue when 515 // delivering the wakeup signal. 516 EventQueue::ScopedMigration migrate(eventQueue()); 517 518 // Kick the vCPU to get it to come out of KVM. 519 kick(); 520 521 if (thread->status() != ThreadContext::Suspended) 522 return; 523 524 thread->activate(); 525} 526 527void 528BaseKvmCPU::activateContext(ThreadID thread_num) 529{ 530 DPRINTF(Kvm, "ActivateContext %d\n", thread_num); 531 532 assert(thread_num == 0); 533 assert(thread); 534 535 assert(_status == Idle); 536 assert(!tickEvent.scheduled()); 537 538 numCycles += ticksToCycles(thread->lastActivate - thread->lastSuspend); 539 540 schedule(tickEvent, clockEdge(Cycles(0))); 541 _status = Running; 542} 543 544 545void 546BaseKvmCPU::suspendContext(ThreadID thread_num) 547{ 548 DPRINTF(Kvm, "SuspendContext %d\n", thread_num); 549 550 assert(thread_num == 0); 551 assert(thread); 552 553 if (_status == Idle) 554 return; 555 556 assert(_status == Running || _status == RunningServiceCompletion); 557 558 // The tick event may no be scheduled if the quest has requested 559 // the monitor to wait for interrupts. The normal CPU models can 560 // get their tick events descheduled by quiesce instructions, but 561 // that can't happen here. 562 if (tickEvent.scheduled()) 563 deschedule(tickEvent); 564 565 _status = Idle; 566} 567 568void 569BaseKvmCPU::deallocateContext(ThreadID thread_num) 570{ 571 // for now, these are equivalent 572 suspendContext(thread_num); 573} 574 575void 576BaseKvmCPU::haltContext(ThreadID thread_num) 577{ 578 // for now, these are equivalent 579 suspendContext(thread_num); 580} 581 582ThreadContext * 583BaseKvmCPU::getContext(int tn) 584{ 585 assert(tn == 0); 586 syncThreadContext(); 587 return tc; 588} 589 590 591Counter 592BaseKvmCPU::totalInsts() const 593{ 594 return ctrInsts; 595} 596 597Counter 598BaseKvmCPU::totalOps() const 599{ 600 hack_once("Pretending totalOps is equivalent to totalInsts()\n"); 601 return ctrInsts; 602} 603 604void 605BaseKvmCPU::dump() const 606{ 607 inform("State dumping not implemented."); 608} 609 610void 611BaseKvmCPU::tick() 612{ 613 Tick delay(0); 614 assert(_status != Idle && _status != RunningMMIOPending); 615 616 switch (_status) { 617 case RunningService: 618 // handleKvmExit() will determine the next state of the CPU 619 delay = handleKvmExit(); 620 621 if (tryDrain()) 622 _status = Idle; 623 break; 624 625 case RunningServiceCompletion: 626 case Running: { 627 const uint64_t nextInstEvent( 628 !comInstEventQueue[0]->empty() ? 629 comInstEventQueue[0]->nextTick() : UINT64_MAX); 630 // Enter into KVM and complete pending IO instructions if we 631 // have an instruction event pending. 632 const Tick ticksToExecute( 633 nextInstEvent > ctrInsts ? 634 curEventQueue()->nextTick() - curTick() : 0); 635 636 if (alwaysSyncTC) 637 threadContextDirty = true; 638 639 // We might need to update the KVM state. 640 syncKvmState(); 641 642 // Setup any pending instruction count breakpoints using 643 // PerfEvent if we are going to execute more than just an IO 644 // completion. 645 if (ticksToExecute > 0) 646 setupInstStop(); 647 648 DPRINTF(KvmRun, "Entering KVM...\n"); 649 if (drainState() == DrainState::Draining) { 650 // Force an immediate exit from KVM after completing 651 // pending operations. The architecture-specific code 652 // takes care to run until it is in a state where it can 653 // safely be drained. 654 delay = kvmRunDrain(); 655 } else { 656 delay = kvmRun(ticksToExecute); 657 } 658 659 // The CPU might have been suspended before entering into 660 // KVM. Assume that the CPU was suspended /before/ entering 661 // into KVM and skip the exit handling. 662 if (_status == Idle) 663 break; 664 665 // Entering into KVM implies that we'll have to reload the thread 666 // context from KVM if we want to access it. Flag the KVM state as 667 // dirty with respect to the cached thread context. 668 kvmStateDirty = true; 669 670 if (alwaysSyncTC) 671 syncThreadContext(); 672 673 // Enter into the RunningService state unless the 674 // simulation was stopped by a timer. 675 if (_kvmRun->exit_reason != KVM_EXIT_INTR) { 676 _status = RunningService; 677 } else { 678 ++numExitSignal; 679 _status = Running; 680 } 681 682 // Service any pending instruction events. The vCPU should 683 // have exited in time for the event using the instruction 684 // counter configured by setupInstStop(). 685 comInstEventQueue[0]->serviceEvents(ctrInsts); 686 system->instEventQueue.serviceEvents(system->totalNumInsts); 687 688 if (tryDrain()) 689 _status = Idle; 690 } break; 691 692 default: 693 panic("BaseKvmCPU entered tick() in an illegal state (%i)\n", 694 _status); 695 } 696 697 // Schedule a new tick if we are still running 698 if (_status != Idle && _status != RunningMMIOPending) 699 schedule(tickEvent, clockEdge(ticksToCycles(delay))); 700} 701 702Tick 703BaseKvmCPU::kvmRunDrain() 704{ 705 // By default, the only thing we need to drain is a pending IO 706 // operation which assumes that we are in the 707 // RunningServiceCompletion or RunningMMIOPending state. 708 assert(_status == RunningServiceCompletion || 709 _status == RunningMMIOPending); 710 711 // Deliver the data from the pending IO operation and immediately 712 // exit. 713 return kvmRun(0); 714} 715 716uint64_t 717BaseKvmCPU::getHostCycles() const 718{ 719 return hwCycles.read(); 720} 721 722Tick 723BaseKvmCPU::kvmRun(Tick ticks) 724{ 725 Tick ticksExecuted; 726 fatal_if(vcpuFD == -1, 727 "Trying to run a KVM CPU in a forked child process. " 728 "This is not supported.\n"); 729 DPRINTF(KvmRun, "KVM: Executing for %i ticks\n", ticks); 730 731 if (ticks == 0) { 732 // Settings ticks == 0 is a special case which causes an entry 733 // into KVM that finishes pending operations (e.g., IO) and 734 // then immediately exits. 735 DPRINTF(KvmRun, "KVM: Delivering IO without full guest entry\n"); 736 737 ++numVMHalfEntries; 738 739 // Send a KVM_KICK_SIGNAL to the vCPU thread (i.e., this 740 // thread). The KVM control signal is masked while executing 741 // in gem5 and gets unmasked temporarily as when entering 742 // KVM. See setSignalMask() and setupSignalHandler(). 743 kick(); 744 745 // Start the vCPU. KVM will check for signals after completing 746 // pending operations (IO). Since the KVM_KICK_SIGNAL is 747 // pending, this forces an immediate exit to gem5 again. We 748 // don't bother to setup timers since this shouldn't actually 749 // execute any code (other than completing half-executed IO 750 // instructions) in the guest. 751 ioctlRun(); 752 753 // We always execute at least one cycle to prevent the 754 // BaseKvmCPU::tick() to be rescheduled on the same tick 755 // twice. 756 ticksExecuted = clockPeriod(); 757 } else { 758 // This method is executed as a result of a tick event. That 759 // means that the event queue will be locked when entering the 760 // method. We temporarily unlock the event queue to allow 761 // other threads to steal control of this thread to inject 762 // interrupts. They will typically lock the queue and then 763 // force an exit from KVM by kicking the vCPU. 764 EventQueue::ScopedRelease release(curEventQueue()); 765 766 if (ticks < runTimer->resolution()) { 767 DPRINTF(KvmRun, "KVM: Adjusting tick count (%i -> %i)\n", 768 ticks, runTimer->resolution()); 769 ticks = runTimer->resolution(); 770 } 771 772 // Get hardware statistics after synchronizing contexts. The KVM 773 // state update might affect guest cycle counters. 774 uint64_t baseCycles(getHostCycles()); 775 uint64_t baseInstrs(hwInstructions.read()); 776 777 // Arm the run timer and start the cycle timer if it isn't 778 // controlled by the overflow timer. Starting/stopping the cycle 779 // timer automatically starts the other perf timers as they are in 780 // the same counter group. 781 runTimer->arm(ticks); 782 if (!perfControlledByTimer) 783 hwCycles.start(); 784 785 ioctlRun(); 786 787 runTimer->disarm(); 788 if (!perfControlledByTimer) 789 hwCycles.stop(); 790 791 // The control signal may have been delivered after we exited 792 // from KVM. It will be pending in that case since it is 793 // masked when we aren't executing in KVM. Discard it to make 794 // sure we don't deliver it immediately next time we try to 795 // enter into KVM. 796 discardPendingSignal(KVM_KICK_SIGNAL); 797 798 const uint64_t hostCyclesExecuted(getHostCycles() - baseCycles); 799 const uint64_t simCyclesExecuted(hostCyclesExecuted * hostFactor); 800 const uint64_t instsExecuted(hwInstructions.read() - baseInstrs); 801 ticksExecuted = runTimer->ticksFromHostCycles(hostCyclesExecuted); 802 803 /* Update statistics */ 804 numCycles += simCyclesExecuted;; 805 numInsts += instsExecuted; 806 ctrInsts += instsExecuted; 807 system->totalNumInsts += instsExecuted; 808 809 DPRINTF(KvmRun, 810 "KVM: Executed %i instructions in %i cycles " 811 "(%i ticks, sim cycles: %i).\n", 812 instsExecuted, hostCyclesExecuted, ticksExecuted, simCyclesExecuted); 813 } 814 815 ++numVMExits; 816 817 return ticksExecuted + flushCoalescedMMIO(); 818} 819 820void 821BaseKvmCPU::kvmNonMaskableInterrupt() 822{ 823 ++numInterrupts; 824 if (ioctl(KVM_NMI) == -1) 825 panic("KVM: Failed to deliver NMI to virtual CPU\n"); 826} 827 828void 829BaseKvmCPU::kvmInterrupt(const struct kvm_interrupt &interrupt) 830{ 831 ++numInterrupts; 832 if (ioctl(KVM_INTERRUPT, (void *)&interrupt) == -1) 833 panic("KVM: Failed to deliver interrupt to virtual CPU\n"); 834} 835 836void 837BaseKvmCPU::getRegisters(struct kvm_regs ®s) const 838{ 839 if (ioctl(KVM_GET_REGS, ®s) == -1) 840 panic("KVM: Failed to get guest registers\n"); 841} 842 843void 844BaseKvmCPU::setRegisters(const struct kvm_regs ®s) 845{ 846 if (ioctl(KVM_SET_REGS, (void *)®s) == -1) 847 panic("KVM: Failed to set guest registers\n"); 848} 849 850void 851BaseKvmCPU::getSpecialRegisters(struct kvm_sregs ®s) const 852{ 853 if (ioctl(KVM_GET_SREGS, ®s) == -1) 854 panic("KVM: Failed to get guest special registers\n"); 855} 856 857void 858BaseKvmCPU::setSpecialRegisters(const struct kvm_sregs ®s) 859{ 860 if (ioctl(KVM_SET_SREGS, (void *)®s) == -1) 861 panic("KVM: Failed to set guest special registers\n"); 862} 863 864void 865BaseKvmCPU::getFPUState(struct kvm_fpu &state) const 866{ 867 if (ioctl(KVM_GET_FPU, &state) == -1) 868 panic("KVM: Failed to get guest FPU state\n"); 869} 870 871void 872BaseKvmCPU::setFPUState(const struct kvm_fpu &state) 873{ 874 if (ioctl(KVM_SET_FPU, (void *)&state) == -1) 875 panic("KVM: Failed to set guest FPU state\n"); 876} 877 878 879void 880BaseKvmCPU::setOneReg(uint64_t id, const void *addr) 881{ 882#ifdef KVM_SET_ONE_REG 883 struct kvm_one_reg reg; 884 reg.id = id; 885 reg.addr = (uint64_t)addr; 886 887 if (ioctl(KVM_SET_ONE_REG, ®) == -1) { 888 panic("KVM: Failed to set register (0x%x) value (errno: %i)\n", 889 id, errno); 890 } 891#else 892 panic("KVM_SET_ONE_REG is unsupported on this platform.\n"); 893#endif 894} 895 896void 897BaseKvmCPU::getOneReg(uint64_t id, void *addr) const 898{ 899#ifdef KVM_GET_ONE_REG 900 struct kvm_one_reg reg; 901 reg.id = id; 902 reg.addr = (uint64_t)addr; 903 904 if (ioctl(KVM_GET_ONE_REG, ®) == -1) { 905 panic("KVM: Failed to get register (0x%x) value (errno: %i)\n", 906 id, errno); 907 } 908#else 909 panic("KVM_GET_ONE_REG is unsupported on this platform.\n"); 910#endif 911} 912 913std::string 914BaseKvmCPU::getAndFormatOneReg(uint64_t id) const 915{ 916#ifdef KVM_GET_ONE_REG 917 std::ostringstream ss; 918 919 ss.setf(std::ios::hex, std::ios::basefield); 920 ss.setf(std::ios::showbase); 921#define HANDLE_INTTYPE(len) \ 922 case KVM_REG_SIZE_U ## len: { \ 923 uint ## len ## _t value; \ 924 getOneReg(id, &value); \ 925 ss << value; \ 926 } break 927 928#define HANDLE_ARRAY(len) \ 929 case KVM_REG_SIZE_U ## len: { \ 930 uint8_t value[len / 8]; \ 931 getOneReg(id, value); \ 932 ccprintf(ss, "[0x%x", value[0]); \ 933 for (int i = 1; i < len / 8; ++i) \ 934 ccprintf(ss, ", 0x%x", value[i]); \ 935 ccprintf(ss, "]"); \ 936 } break 937 938 switch (id & KVM_REG_SIZE_MASK) { 939 HANDLE_INTTYPE(8); 940 HANDLE_INTTYPE(16); 941 HANDLE_INTTYPE(32); 942 HANDLE_INTTYPE(64); 943 HANDLE_ARRAY(128); 944 HANDLE_ARRAY(256); 945 HANDLE_ARRAY(512); 946 HANDLE_ARRAY(1024); 947 default: 948 ss << "??"; 949 } 950 951#undef HANDLE_INTTYPE 952#undef HANDLE_ARRAY 953 954 return ss.str(); 955#else 956 panic("KVM_GET_ONE_REG is unsupported on this platform.\n"); 957#endif 958} 959 960void 961BaseKvmCPU::syncThreadContext() 962{ 963 if (!kvmStateDirty) 964 return; 965 966 assert(!threadContextDirty); 967 968 updateThreadContext(); 969 kvmStateDirty = false; 970} 971 972void 973BaseKvmCPU::syncKvmState() 974{ 975 if (!threadContextDirty) 976 return; 977 978 assert(!kvmStateDirty); 979 980 updateKvmState(); 981 threadContextDirty = false; 982} 983 984Tick 985BaseKvmCPU::handleKvmExit() 986{ 987 DPRINTF(KvmRun, "handleKvmExit (exit_reason: %i)\n", _kvmRun->exit_reason); 988 assert(_status == RunningService); 989 990 // Switch into the running state by default. Individual handlers 991 // can override this. 992 _status = Running; 993 switch (_kvmRun->exit_reason) { 994 case KVM_EXIT_UNKNOWN: 995 return handleKvmExitUnknown(); 996 997 case KVM_EXIT_EXCEPTION: 998 return handleKvmExitException(); 999 1000 case KVM_EXIT_IO: 1001 { 1002 ++numIO; 1003 Tick ticks = handleKvmExitIO(); 1004 _status = dataPort.nextIOState(); 1005 return ticks; 1006 } 1007 1008 case KVM_EXIT_HYPERCALL: 1009 ++numHypercalls; 1010 return handleKvmExitHypercall(); 1011 1012 case KVM_EXIT_HLT: 1013 /* The guest has halted and is waiting for interrupts */ 1014 DPRINTF(Kvm, "handleKvmExitHalt\n"); 1015 ++numHalt; 1016 1017 // Suspend the thread until the next interrupt arrives 1018 thread->suspend(); 1019 1020 // This is actually ignored since the thread is suspended. 1021 return 0; 1022 1023 case KVM_EXIT_MMIO: 1024 { 1025 /* Service memory mapped IO requests */ 1026 DPRINTF(KvmIO, "KVM: Handling MMIO (w: %u, addr: 0x%x, len: %u)\n", 1027 _kvmRun->mmio.is_write, 1028 _kvmRun->mmio.phys_addr, _kvmRun->mmio.len); 1029 1030 ++numMMIO; 1031 Tick ticks = doMMIOAccess(_kvmRun->mmio.phys_addr, _kvmRun->mmio.data, 1032 _kvmRun->mmio.len, _kvmRun->mmio.is_write); 1033 // doMMIOAccess could have triggered a suspend, in which case we don't 1034 // want to overwrite the _status. 1035 if (_status != Idle) 1036 _status = dataPort.nextIOState(); 1037 return ticks; 1038 } 1039 1040 case KVM_EXIT_IRQ_WINDOW_OPEN: 1041 return handleKvmExitIRQWindowOpen(); 1042 1043 case KVM_EXIT_FAIL_ENTRY: 1044 return handleKvmExitFailEntry(); 1045 1046 case KVM_EXIT_INTR: 1047 /* KVM was interrupted by a signal, restart it in the next 1048 * tick. */ 1049 return 0; 1050 1051 case KVM_EXIT_INTERNAL_ERROR: 1052 panic("KVM: Internal error (suberror: %u)\n", 1053 _kvmRun->internal.suberror); 1054 1055 default: 1056 dump(); 1057 panic("KVM: Unexpected exit (exit_reason: %u)\n", _kvmRun->exit_reason); 1058 } 1059} 1060 1061Tick 1062BaseKvmCPU::handleKvmExitIO() 1063{ 1064 panic("KVM: Unhandled guest IO (dir: %i, size: %i, port: 0x%x, count: %i)\n", 1065 _kvmRun->io.direction, _kvmRun->io.size, 1066 _kvmRun->io.port, _kvmRun->io.count); 1067} 1068 1069Tick 1070BaseKvmCPU::handleKvmExitHypercall() 1071{ 1072 panic("KVM: Unhandled hypercall\n"); 1073} 1074 1075Tick 1076BaseKvmCPU::handleKvmExitIRQWindowOpen() 1077{ 1078 warn("KVM: Unhandled IRQ window.\n"); 1079 return 0; 1080} 1081 1082 1083Tick 1084BaseKvmCPU::handleKvmExitUnknown() 1085{ 1086 dump(); 1087 panic("KVM: Unknown error when starting vCPU (hw reason: 0x%llx)\n", 1088 _kvmRun->hw.hardware_exit_reason); 1089} 1090 1091Tick 1092BaseKvmCPU::handleKvmExitException() 1093{ 1094 dump(); 1095 panic("KVM: Got exception when starting vCPU " 1096 "(exception: %u, error_code: %u)\n", 1097 _kvmRun->ex.exception, _kvmRun->ex.error_code); 1098} 1099 1100Tick 1101BaseKvmCPU::handleKvmExitFailEntry() 1102{ 1103 dump(); 1104 panic("KVM: Failed to enter virtualized mode (hw reason: 0x%llx)\n", 1105 _kvmRun->fail_entry.hardware_entry_failure_reason); 1106} 1107 1108Tick 1109BaseKvmCPU::doMMIOAccess(Addr paddr, void *data, int size, bool write) 1110{ 1111 ThreadContext *tc(thread->getTC()); 1112 syncThreadContext(); 1113 1114 RequestPtr mmio_req = new Request(paddr, size, Request::UNCACHEABLE, 1115 dataMasterId()); 1116 mmio_req->setContext(tc->contextId()); 1117 // Some architectures do need to massage physical addresses a bit 1118 // before they are inserted into the memory system. This enables 1119 // APIC accesses on x86 and m5ops where supported through a MMIO 1120 // interface. 1121 BaseTLB::Mode tlb_mode(write ? BaseTLB::Write : BaseTLB::Read); 1122 Fault fault(tc->getDTBPtr()->finalizePhysical(mmio_req, tc, tlb_mode)); 1123 if (fault != NoFault) 1124 warn("Finalization of MMIO address failed: %s\n", fault->name()); 1125 1126 1127 const MemCmd cmd(write ? MemCmd::WriteReq : MemCmd::ReadReq); 1128 PacketPtr pkt = new Packet(mmio_req, cmd); 1129 pkt->dataStatic(data); 1130 1131 if (mmio_req->isMmappedIpr()) { 1132 // We currently assume that there is no need to migrate to a 1133 // different event queue when doing IPRs. Currently, IPRs are 1134 // only used for m5ops, so it should be a valid assumption. 1135 const Cycles ipr_delay(write ? 1136 TheISA::handleIprWrite(tc, pkt) : 1137 TheISA::handleIprRead(tc, pkt)); 1138 threadContextDirty = true; 1139 delete pkt->req; 1140 delete pkt; 1141 return clockPeriod() * ipr_delay; 1142 } else { 1143 // Temporarily lock and migrate to the event queue of the 1144 // VM. This queue is assumed to "own" all devices we need to 1145 // access if running in multi-core mode. 1146 EventQueue::ScopedMigration migrate(vm.eventQueue()); 1147 1148 return dataPort.submitIO(pkt); 1149 } 1150} 1151 1152void 1153BaseKvmCPU::setSignalMask(const sigset_t *mask) 1154{ 1155 std::unique_ptr<struct kvm_signal_mask> kvm_mask; 1156 1157 if (mask) { 1158 kvm_mask.reset((struct kvm_signal_mask *)operator new( 1159 sizeof(struct kvm_signal_mask) + sizeof(*mask))); 1160 // The kernel and the user-space headers have different ideas 1161 // about the size of sigset_t. This seems like a massive hack, 1162 // but is actually what qemu does. 1163 assert(sizeof(*mask) >= 8); 1164 kvm_mask->len = 8; 1165 memcpy(kvm_mask->sigset, mask, kvm_mask->len); 1166 } 1167 1168 if (ioctl(KVM_SET_SIGNAL_MASK, (void *)kvm_mask.get()) == -1) 1169 panic("KVM: Failed to set vCPU signal mask (errno: %i)\n", 1170 errno); 1171} 1172 1173int 1174BaseKvmCPU::ioctl(int request, long p1) const 1175{ 1176 if (vcpuFD == -1) 1177 panic("KVM: CPU ioctl called before initialization\n"); 1178 1179 return ::ioctl(vcpuFD, request, p1); 1180} 1181 1182Tick 1183BaseKvmCPU::flushCoalescedMMIO() 1184{ 1185 if (!mmioRing) 1186 return 0; 1187 1188 DPRINTF(KvmIO, "KVM: Flushing the coalesced MMIO ring buffer\n"); 1189 1190 // TODO: We might need to do synchronization when we start to 1191 // support multiple CPUs 1192 Tick ticks(0); 1193 while (mmioRing->first != mmioRing->last) { 1194 struct kvm_coalesced_mmio &ent( 1195 mmioRing->coalesced_mmio[mmioRing->first]); 1196 1197 DPRINTF(KvmIO, "KVM: Handling coalesced MMIO (addr: 0x%x, len: %u)\n", 1198 ent.phys_addr, ent.len); 1199 1200 ++numCoalescedMMIO; 1201 ticks += doMMIOAccess(ent.phys_addr, ent.data, ent.len, true); 1202 1203 mmioRing->first = (mmioRing->first + 1) % KVM_COALESCED_MMIO_MAX; 1204 } 1205 1206 return ticks; 1207} 1208 1209/** 1210 * Dummy handler for KVM kick signals. 1211 * 1212 * @note This function is usually not called since the kernel doesn't 1213 * seem to deliver signals when the signal is only unmasked when 1214 * running in KVM. This doesn't matter though since we are only 1215 * interested in getting KVM to exit, which happens as expected. See 1216 * setupSignalHandler() and kvmRun() for details about KVM signal 1217 * handling. 1218 */ 1219static void 1220onKickSignal(int signo, siginfo_t *si, void *data) 1221{ 1222} 1223 1224void 1225BaseKvmCPU::setupSignalHandler() 1226{ 1227 struct sigaction sa; 1228 1229 memset(&sa, 0, sizeof(sa)); 1230 sa.sa_sigaction = onKickSignal; 1231 sa.sa_flags = SA_SIGINFO | SA_RESTART; 1232 if (sigaction(KVM_KICK_SIGNAL, &sa, NULL) == -1) 1233 panic("KVM: Failed to setup vCPU timer signal handler\n"); 1234 1235 sigset_t sigset; 1236 if (pthread_sigmask(SIG_BLOCK, NULL, &sigset) == -1) 1237 panic("KVM: Failed get signal mask\n"); 1238 1239 // Request KVM to setup the same signal mask as we're currently 1240 // running with except for the KVM control signal. We'll sometimes 1241 // need to raise the KVM_KICK_SIGNAL to cause immediate exits from 1242 // KVM after servicing IO requests. See kvmRun(). 1243 sigdelset(&sigset, KVM_KICK_SIGNAL); 1244 setSignalMask(&sigset); 1245 1246 // Mask our control signals so they aren't delivered unless we're 1247 // actually executing inside KVM. 1248 sigaddset(&sigset, KVM_KICK_SIGNAL); 1249 if (pthread_sigmask(SIG_SETMASK, &sigset, NULL) == -1) 1250 panic("KVM: Failed mask the KVM control signals\n"); 1251} 1252 1253bool 1254BaseKvmCPU::discardPendingSignal(int signum) const 1255{ 1256 int discardedSignal; 1257 1258 // Setting the timeout to zero causes sigtimedwait to return 1259 // immediately. 1260 struct timespec timeout; 1261 timeout.tv_sec = 0; 1262 timeout.tv_nsec = 0; 1263 1264 sigset_t sigset; 1265 sigemptyset(&sigset); 1266 sigaddset(&sigset, signum); 1267 1268 do { 1269 discardedSignal = sigtimedwait(&sigset, NULL, &timeout); 1270 } while (discardedSignal == -1 && errno == EINTR); 1271 1272 if (discardedSignal == signum) 1273 return true; 1274 else if (discardedSignal == -1 && errno == EAGAIN) 1275 return false; 1276 else 1277 panic("Unexpected return value from sigtimedwait: %i (errno: %i)\n", 1278 discardedSignal, errno); 1279} 1280 1281void 1282BaseKvmCPU::setupCounters() 1283{ 1284 DPRINTF(Kvm, "Attaching cycle counter...\n"); 1285 PerfKvmCounterConfig cfgCycles(PERF_TYPE_HARDWARE, 1286 PERF_COUNT_HW_CPU_CYCLES); 1287 cfgCycles.disabled(true) 1288 .pinned(true); 1289 1290 // Try to exclude the host. We set both exclude_hv and 1291 // exclude_host since different architectures use slightly 1292 // different APIs in the kernel. 1293 cfgCycles.exclude_hv(true) 1294 .exclude_host(true); 1295 1296 if (perfControlledByTimer) { 1297 // We need to configure the cycles counter to send overflows 1298 // since we are going to use it to trigger timer signals that 1299 // trap back into m5 from KVM. In practice, this means that we 1300 // need to set some non-zero sample period that gets 1301 // overridden when the timer is armed. 1302 cfgCycles.wakeupEvents(1) 1303 .samplePeriod(42); 1304 } 1305 1306 hwCycles.attach(cfgCycles, 1307 0); // TID (0 => currentThread) 1308 1309 setupInstCounter(); 1310} 1311 1312bool 1313BaseKvmCPU::tryDrain() 1314{ 1315 if (drainState() != DrainState::Draining) 1316 return false; 1317 1318 if (!archIsDrained()) { 1319 DPRINTF(Drain, "tryDrain: Architecture code is not ready.\n"); 1320 return false; 1321 } 1322 1323 if (_status == Idle || _status == Running) { 1324 DPRINTF(Drain, 1325 "tryDrain: CPU transitioned into the Idle state, drain done\n"); 1326 signalDrainDone(); 1327 return true; 1328 } else { 1329 DPRINTF(Drain, "tryDrain: CPU not ready.\n"); 1330 return false; 1331 } 1332} 1333 1334void 1335BaseKvmCPU::ioctlRun() 1336{ 1337 if (ioctl(KVM_RUN) == -1) { 1338 if (errno != EINTR) 1339 panic("KVM: Failed to start virtual CPU (errno: %i)\n", 1340 errno); 1341 } 1342} 1343 1344void 1345BaseKvmCPU::setupInstStop() 1346{ 1347 if (comInstEventQueue[0]->empty()) { 1348 setupInstCounter(0); 1349 } else { 1350 const uint64_t next(comInstEventQueue[0]->nextTick()); 1351 1352 assert(next > ctrInsts); 1353 setupInstCounter(next - ctrInsts); 1354 } 1355} 1356 1357void 1358BaseKvmCPU::setupInstCounter(uint64_t period) 1359{ 1360 // No need to do anything if we aren't attaching for the first 1361 // time or the period isn't changing. 1362 if (period == activeInstPeriod && hwInstructions.attached()) 1363 return; 1364 1365 PerfKvmCounterConfig cfgInstructions(PERF_TYPE_HARDWARE, 1366 PERF_COUNT_HW_INSTRUCTIONS); 1367 1368 // Try to exclude the host. We set both exclude_hv and 1369 // exclude_host since different architectures use slightly 1370 // different APIs in the kernel. 1371 cfgInstructions.exclude_hv(true) 1372 .exclude_host(true); 1373 1374 if (period) { 1375 // Setup a sampling counter if that has been requested. 1376 cfgInstructions.wakeupEvents(1) 1377 .samplePeriod(period); 1378 } 1379 1380 // We need to detach and re-attach the counter to reliably change 1381 // sampling settings. See PerfKvmCounter::period() for details. 1382 if (hwInstructions.attached()) 1383 hwInstructions.detach(); 1384 assert(hwCycles.attached()); 1385 hwInstructions.attach(cfgInstructions, 1386 0, // TID (0 => currentThread) 1387 hwCycles); 1388 1389 if (period) 1390 hwInstructions.enableSignals(KVM_KICK_SIGNAL); 1391 1392 activeInstPeriod = period; 1393} 1394