cachepc-qemu

Fork of AMDESE/qemu with changes for cachepc side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-qemu
Log | Files | Refs | Submodules | LICENSE | sfeed.txt

tcg-accel-ops-icount.c (4711B)

      1/*
      2 * QEMU TCG Single Threaded vCPUs implementation using instruction counting
      3 *
      4 * Copyright (c) 2003-2008 Fabrice Bellard
      5 * Copyright (c) 2014 Red Hat Inc.
      6 *
      7 * Permission is hereby granted, free of charge, to any person obtaining a copy
      8 * of this software and associated documentation files (the "Software"), to deal
      9 * in the Software without restriction, including without limitation the rights
     10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     11 * copies of the Software, and to permit persons to whom the Software is
     12 * furnished to do so, subject to the following conditions:
     13 *
     14 * The above copyright notice and this permission notice shall be included in
     15 * all copies or substantial portions of the Software.
     16 *
     17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
     20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
     23 * THE SOFTWARE.
     24 */
     25
     26#include "qemu/osdep.h"
     27#include "qemu-common.h"
     28#include "sysemu/tcg.h"
     29#include "sysemu/replay.h"
     30#include "qemu/main-loop.h"
     31#include "qemu/guest-random.h"
     32#include "exec/exec-all.h"
     33
     34#include "tcg-accel-ops.h"
     35#include "tcg-accel-ops-icount.h"
     36#include "tcg-accel-ops-rr.h"
     37
     38static int64_t icount_get_limit(void)
     39{
     40    int64_t deadline;
     41
     42    if (replay_mode != REPLAY_MODE_PLAY) {
     43        /*
     44         * Include all the timers, because they may need an attention.
     45         * Too long CPU execution may create unnecessary delay in UI.
     46         */
     47        deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
     48                                              QEMU_TIMER_ATTR_ALL);
     49        /* Check realtime timers, because they help with input processing */
     50        deadline = qemu_soonest_timeout(deadline,
     51                qemu_clock_deadline_ns_all(QEMU_CLOCK_REALTIME,
     52                                           QEMU_TIMER_ATTR_ALL));
     53
     54        /*
     55         * Maintain prior (possibly buggy) behaviour where if no deadline
     56         * was set (as there is no QEMU_CLOCK_VIRTUAL timer) or it is more than
     57         * INT32_MAX nanoseconds ahead, we still use INT32_MAX
     58         * nanoseconds.
     59         */
     60        if ((deadline < 0) || (deadline > INT32_MAX)) {
     61            deadline = INT32_MAX;
     62        }
     63
     64        return icount_round(deadline);
     65    } else {
     66        return replay_get_instructions();
     67    }
     68}
     69
     70static void icount_notify_aio_contexts(void)
     71{
     72    /* Wake up other AioContexts.  */
     73    qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
     74    qemu_clock_run_timers(QEMU_CLOCK_VIRTUAL);
     75}
     76
     77void icount_handle_deadline(void)
     78{
     79    assert(qemu_in_vcpu_thread());
     80    int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
     81                                                  QEMU_TIMER_ATTR_ALL);
     82
     83    /*
     84     * Instructions, interrupts, and exceptions are processed in cpu-exec.
     85     * Don't interrupt cpu thread, when these events are waiting
     86     * (i.e., there is no checkpoint)
     87     */
     88    if (deadline == 0
     89        && (replay_mode != REPLAY_MODE_PLAY || replay_has_checkpoint())) {
     90        icount_notify_aio_contexts();
     91    }
     92}
     93
     94void icount_prepare_for_run(CPUState *cpu)
     95{
     96    int insns_left;
     97
     98    /*
     99     * These should always be cleared by icount_process_data after
    100     * each vCPU execution. However u16.high can be raised
    101     * asynchronously by cpu_exit/cpu_interrupt/tcg_handle_interrupt
    102     */
    103    g_assert(cpu_neg(cpu)->icount_decr.u16.low == 0);
    104    g_assert(cpu->icount_extra == 0);
    105
    106    cpu->icount_budget = icount_get_limit();
    107    insns_left = MIN(0xffff, cpu->icount_budget);
    108    cpu_neg(cpu)->icount_decr.u16.low = insns_left;
    109    cpu->icount_extra = cpu->icount_budget - insns_left;
    110
    111    replay_mutex_lock();
    112
    113    if (cpu->icount_budget == 0 && replay_has_checkpoint()) {
    114        icount_notify_aio_contexts();
    115    }
    116}
    117
    118void icount_process_data(CPUState *cpu)
    119{
    120    /* Account for executed instructions */
    121    icount_update(cpu);
    122
    123    /* Reset the counters */
    124    cpu_neg(cpu)->icount_decr.u16.low = 0;
    125    cpu->icount_extra = 0;
    126    cpu->icount_budget = 0;
    127
    128    replay_account_executed_instructions();
    129
    130    replay_mutex_unlock();
    131}
    132
    133void icount_handle_interrupt(CPUState *cpu, int mask)
    134{
    135    int old_mask = cpu->interrupt_request;
    136
    137    tcg_handle_interrupt(cpu, mask);
    138    if (qemu_cpu_is_self(cpu) &&
    139        !cpu->can_do_io
    140        && (mask & ~old_mask) != 0) {
    141        cpu_abort(cpu, "Raised interrupt while not in I/O function");
    142    }
    143}