summaryrefslogtreecommitdiff
path: root/src/cpu/kvm/base.hh
blob: 4546b10711c875aa751ae112f54c99c36783ecc5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
/*
 * Copyright (c) 2012 ARM Limited
 * All rights reserved
 *
 * The license below extends only to copyright in the software and shall
 * not be construed as granting a license to any other intellectual
 * property including but not limited to intellectual property relating
 * to a hardware implementation of the functionality of the software
 * licensed hereunder.  You may use the software subject to the license
 * terms below provided that you ensure that this notice is replicated
 * unmodified and in its entirety in all distributions of the software,
 * modified or unmodified, in source code or in binary form.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Andreas Sandberg
 */

#ifndef __CPU_KVM_BASE_HH__
#define __CPU_KVM_BASE_HH__

#include <memory>

#include "base/statistics.hh"
#include "cpu/kvm/perfevent.hh"
#include "cpu/kvm/timer.hh"
#include "cpu/kvm/vm.hh"
#include "cpu/base.hh"
#include "cpu/simple_thread.hh"

/** Signal to use to trigger time-based exits from KVM */
#define KVM_TIMER_SIGNAL SIGRTMIN

// forward declarations
class ThreadContext;
struct BaseKvmCPUParams;

/**
 * Base class for KVM based CPU models
 *
 * All architecture specific KVM implementation should inherit from
 * this class. The most basic CPU models only need to override the
 * updateKvmState() and updateThreadContext() methods to implement
 * state synchronization between gem5 and KVM.
 *
 * The architecture specific implementation is also responsible for
 * delivering interrupts into the VM. This is typically done by
 * overriding tick() and checking the thread context before entering
 * into the VM. In order to deliver an interrupt, the implementation
 * then calls KvmVM::setIRQLine() or BaseKvmCPU::kvmInterrupt()
 * depending on the specifics of the underlying hardware/drivers.
 */
class BaseKvmCPU : public BaseCPU
{
  public:
    BaseKvmCPU(BaseKvmCPUParams *params);
    virtual ~BaseKvmCPU();

    void init();
    void startup();
    void regStats();

    void serializeThread(std::ostream &os, ThreadID tid);
    void unserializeThread(Checkpoint *cp, const std::string &section,
                           ThreadID tid);

    unsigned int drain(DrainManager *dm);
    void drainResume();

    void switchOut();
    void takeOverFrom(BaseCPU *cpu);

    void verifyMemoryMode() const;

    MasterPort &getDataPort() { return dataPort; }
    MasterPort &getInstPort() { return instPort; }

    void wakeup();
    void activateContext(ThreadID thread_num, Cycles delay);
    void suspendContext(ThreadID thread_num);
    void deallocateContext(ThreadID thread_num);
    void haltContext(ThreadID thread_num);

    ThreadContext *getContext(int tn);

    Counter totalInsts() const;
    Counter totalOps() const;

    /** Dump the internal state to the terminal. */
    virtual void dump();

    /**
     * A cached copy of a thread's state in the form of a SimpleThread
     * object.
     *
     * Normally the actual thread state is stored in the KVM vCPU. If KVM has
     * been running this copy is will be out of date. If we recently handled
     * some events within gem5 that required state to be updated this could be
     * the most up-to-date copy. When getContext() or updateThreadContext() is
     * called this copy gets updated.  The method syncThreadContext can
     * be used within a KVM CPU to update the thread context if the
     * KVM state is dirty (i.e., the vCPU has been run since the last
     * update).
     */
    SimpleThread *thread;

    /** ThreadContext object, provides an interface for external
     * objects to modify this thread's state.
     */
    ThreadContext *tc;

    KvmVM &vm;

  protected:
    enum Status {
        /** Context not scheduled in KVM */
        Idle,
        /** Running normally */
        Running,
    };

    /** CPU run state */
    Status _status;

    /**
     * Execute the CPU until the next event in the main event queue or
     * until the guest needs service from gem5.
     *
     * @note This method is virtual in order to allow implementations
     * to check for architecture specific events (e.g., interrupts)
     * before entering the VM.
     */
    virtual void tick();

    /**
     * Request KVM to run the guest for a given number of ticks. The
     * method returns the approximate number of ticks executed.
     *
     * @note The returned number of ticks can be both larger or
     * smaller than the requested number of ticks. A smaller number
     * can, for example, occur when the guest executes MMIO. A larger
     * number is typically due to performance counter inaccuracies.
     *
     * @param ticks Number of ticks to execute
     * @return Number of ticks executed (see note)
     */
    Tick kvmRun(Tick ticks);

    /**
     * Get a pointer to the kvm_run structure containing all the input
     * and output parameters from kvmRun().
     */
    struct kvm_run *getKvmRunState() { return _kvmRun; };

    /**
     * Retrieve a pointer to guest data stored at the end of the
     * kvm_run structure. This is mainly used for PIO operations
     * (KVM_EXIT_IO).
     *
     * @param offset Offset as specified by the kvm_run structure
     * @return Pointer to guest data
     */
    uint8_t *getGuestData(uint64_t offset) const {
        return (uint8_t *)_kvmRun + offset;
    };

    /**
     * @addtogroup KvmInterrupts
     * @{
     */
    /**
     * Send a non-maskable interrupt to the guest
     *
     * @note The presence of this call depends on Kvm::capUserNMI().
     */
    void kvmNonMaskableInterrupt();

    /**
     * Send a normal interrupt to the guest
     *
     * @note Make sure that ready_for_interrupt_injection in kvm_run
     * is set prior to calling this function. If not, an interrupt
     * window must be requested by setting request_interrupt_window in
     * kvm_run to 1 and restarting the guest.
     *
     * @param interrupt Structure describing the interrupt to send
     */
    void kvmInterrupt(const struct kvm_interrupt &interrupt);

    /** @} */

    /** @{ */
    /**
     * Get/Set the register state of the guest vCPU
     *
     * KVM has two different interfaces for accessing the state of the
     * guest CPU. One interface updates 'normal' registers and one
     * updates 'special' registers. The distinction between special
     * and normal registers isn't very clear and is architecture
     * dependent.
     */
    void getRegisters(struct kvm_regs &regs) const;
    void setRegisters(const struct kvm_regs &regs);
    void getSpecialRegisters(struct kvm_sregs &regs) const;
    void setSpecialRegisters(const struct kvm_sregs &regs);
    /** @} */

    /** @{ */
    /**
     * Get/Set the guest FPU/vector state
     */
    void getFPUState(struct kvm_fpu &state) const;
    void setFPUState(const struct kvm_fpu &state);
    /** @} */

    /** @{ */
    /**
     * Get/Set single register using the KVM_(SET|GET)_ONE_REG API.
     *
     * @note The presence of this call depends on Kvm::capOneReg().
     */
    void setOneReg(uint64_t id, const void *addr);
    void setOneReg(uint64_t id, uint64_t value) { setOneReg(id, &value); }
    void setOneReg(uint64_t id, uint32_t value) { setOneReg(id, &value); }
    void getOneReg(uint64_t id, void *addr) const;
    uint64_t getOneRegU64(uint64_t id) const {
        uint64_t value;
        getOneReg(id, &value);
        return value;
    }
    uint32_t getOneRegU32(uint64_t id) const {
        uint32_t value;
        getOneReg(id, &value);
        return value;
    }
    /** @} */

    /**
     * Get and format one register for printout.
     *
     * This function call getOneReg() to retrieve the contents of one
     * register and automatically formats it for printing.
     *
     * @note The presence of this call depends on Kvm::capOneReg().
     */
    std::string getAndFormatOneReg(uint64_t id) const;

    /** @{ */
    /**
     * Update the KVM state from the current thread context
     *
     * The base CPU calls this method before starting the guest CPU
     * when the contextDirty flag is set. The architecture dependent
     * CPU implementation is expected to update all guest state
     * (registers, special registers, and FPU state).
     */
    virtual void updateKvmState() = 0;

    /**
     * Update the current thread context with the KVM state
     *
     * The base CPU after the guest updates any of the KVM state. In
     * practice, this happens after kvmRun is called. The architecture
     * dependent code is expected to read the state of the guest CPU
     * and update gem5's thread state.
     */
    virtual void updateThreadContext() = 0;

    /**
     * Update a thread context if the KVM state is dirty with respect
     * to the cached thread context.
     */
    void syncThreadContext();

    /**
     * Update the KVM if the thread context is dirty.
     */
    void syncKvmState();
    /** @} */

    /** @{ */
    /**
     * Main kvmRun exit handler, calls the relevant handleKvmExit*
     * depending on exit type.
     *
     * @return Number of ticks spent servicing the exit request
     */
    virtual Tick handleKvmExit();

    /**
     * The guest performed a legacy IO request (out/inp on x86)
     *
     * @return Number of ticks spent servicing the IO request
     */
    virtual Tick handleKvmExitIO();

    /**
     * The guest requested a monitor service using a hypercall
     *
     * @return Number of ticks spent servicing the hypercall
     */
    virtual Tick handleKvmExitHypercall();

    /**
     * The guest exited because an interrupt window was requested
     *
     * The guest exited because an interrupt window was requested
     * (request_interrupt_window in the kvm_run structure was set to 1
     * before calling kvmRun) and it is now ready to receive
     *
     * @return Number of ticks spent servicing the IRQ
     */
    virtual Tick handleKvmExitIRQWindowOpen();

    /**
     * An unknown architecture dependent error occurred when starting
     * the vCPU
     *
     * The kvm_run data structure contains the hardware error
     * code. The defaults behavior of this method just prints the HW
     * error code and panics. Architecture dependent implementations
     * may want to override this method to provide better,
     * hardware-aware, error messages.
     *
     * @return Number of ticks delay the next CPU tick
     */
    virtual Tick handleKvmExitUnknown();

    /**
     * An unhandled virtualization exception occured
     *
     * Some KVM virtualization drivers return unhandled exceptions to
     * the user-space monitor. This interface is currently only used
     * by the Intel VMX KVM driver.
     *
     * @return Number of ticks delay the next CPU tick
     */
    virtual Tick handleKvmExitException();

    /**
     * KVM failed to start the virtualized CPU
     *
     * The kvm_run data structure contains the hardware-specific error
     * code.
     *
     * @return Number of ticks delay the next CPU tick
     */
    virtual Tick handleKvmExitFailEntry();
    /** @} */

    /**
     * Inject a memory mapped IO request into gem5
     *
     * @param paddr Physical address
     * @param data Pointer to the source/destination buffer
     * @param size Memory access size
     * @param write True if write, False if read
     * @return Number of ticks spent servicing the memory access
     */
    Tick doMMIOAccess(Addr paddr, void *data, int size, bool write);


    /**
     * @addtogroup KvmIoctl
     * @{
     */
    /**
     * vCPU ioctl interface.
     *
     * @param request KVM vCPU request
     * @param p1 Optional request parameter
     *
     * @return -1 on error (error number in errno), ioctl dependent
     * value otherwise.
     */
    int ioctl(int request, long p1) const;
    int ioctl(int request, void *p1) const {
        return ioctl(request, (long)p1);
    }
    int ioctl(int request) const {
        return ioctl(request, 0L);
    }
    /** @} */


    /**
     * KVM memory port. Uses the default MasterPort behavior, but
     * panics on timing accesses.
     */
    class KVMCpuPort : public MasterPort
    {

      public:
        KVMCpuPort(const std::string &_name, BaseKvmCPU *_cpu)
            : MasterPort(_name, _cpu)
        { }

      protected:
        bool recvTimingResp(PacketPtr pkt)
        {
            panic("The KVM CPU doesn't expect recvTimingResp!\n");
            return true;
        }

        void recvRetry()
        {
            panic("The KVM CPU doesn't expect recvRetry!\n");
        }

    };

    /** Port for data requests */
    KVMCpuPort dataPort;

    /** Unused dummy port for the instruction interface */
    KVMCpuPort instPort;

    /** Pre-allocated MMIO memory request */
    Request mmio_req;

    /**
     * Is the gem5 context dirty? Set to true to force an update of
     * the KVM vCPU state upon the next call to kvmRun().
     */
    bool threadContextDirty;

    /**
     * Is the KVM state dirty? Set to true to force an update of
     * the KVM vCPU state upon the next call to kvmRun().
     */
    bool kvmStateDirty;

    /** KVM internal ID of the vCPU */
    const long vcpuID;

  private:
    struct TickEvent : public Event
    {
        BaseKvmCPU &cpu;

        TickEvent(BaseKvmCPU &c)
            : Event(CPU_Tick_Pri), cpu(c) {}

        void process() { cpu.tick(); }

        const char *description() const {
            return "BaseKvmCPU tick";
        }
    };

    /**
     * Service MMIO requests in the mmioRing.
     *
     *
     * @return Number of ticks spent servicing the MMIO requests in
     * the MMIO ring buffer
     */
    Tick flushCoalescedMMIO();

    /**
     * Setup a signal handler to catch the timer signal used to
     * switch back to the monitor.
     */
    void setupSignalHandler();

    /** Setup hardware performance counters */
    void setupCounters();

    /** KVM vCPU file descriptor */
    int vcpuFD;
    /** Size of MMAPed kvm_run area */
    int vcpuMMapSize;
    /**
     * Pointer to the kvm_run structure used to communicate parameters
     * with KVM.
     *
     * @note This is the base pointer of the MMAPed KVM region. The
     * first page contains the kvm_run structure. Subsequent pages may
     * contain other data such as the MMIO ring buffer.
     */
    struct kvm_run *_kvmRun;
    /**
     * Coalesced MMIO ring buffer. NULL if coalesced MMIO is not
     * supported.
     */
    struct kvm_coalesced_mmio_ring *mmioRing;
    /** Cached page size of the host */
    const long pageSize;

    TickEvent tickEvent;

    /** @{ */
    /** Guest performance counters */
    PerfKvmCounter hwCycles;
    PerfKvmCounter hwInstructions;
    /** @} */

    /**
     * Does the runTimer control the performance counters?
     *
     * The run timer will automatically enable and disable performance
     * counters if a PerfEvent-based timer is used to control KVM
     * exits.
     */
    bool perfControlledByTimer;

    /**
     * Timer used to force execution into the monitor after a
     * specified number of simulation tick equivalents have executed
     * in the guest. This counter generates the signal specified by
     * KVM_TIMER_SIGNAL.
     */
    std::unique_ptr<BaseKvmTimer> runTimer;

    float hostFactor;

  public:
    /* @{ */
    Stats::Scalar numInsts;
    Stats::Scalar numVMExits;
    Stats::Scalar numMMIO;
    Stats::Scalar numCoalescedMMIO;
    Stats::Scalar numIO;
    Stats::Scalar numHalt;
    Stats::Scalar numInterrupts;
    Stats::Scalar numHypercalls;
    /* @} */
};

#endif