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/*
* QEMU TCG Single Threaded vCPUs implementation using instruction counting
*
* Copyright (c) 2003-2008 Fabrice Bellard
* Copyright (c) 2014 Red Hat Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "sysemu/replay.h"
#include "sysemu/cpu-timers.h"
#include "qemu/main-loop.h"
#include "qemu/guest-random.h"
#include "exec/exec-all.h"
#include "tcg-accel-ops.h"
#include "tcg-accel-ops-icount.h"
#include "tcg-accel-ops-rr.h"
static int64_t icount_get_limit(void)
{
int64_t deadline;
if (replay_mode != REPLAY_MODE_PLAY) {
/*
* Include all the timers, because they may need an attention.
* Too long CPU execution may create unnecessary delay in UI.
*/
deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
QEMU_TIMER_ATTR_ALL);
/* Check realtime timers, because they help with input processing */
deadline = qemu_soonest_timeout(deadline,
qemu_clock_deadline_ns_all(QEMU_CLOCK_REALTIME,
QEMU_TIMER_ATTR_ALL));
/*
* Maintain prior (possibly buggy) behaviour where if no deadline
* was set (as there is no QEMU_CLOCK_VIRTUAL timer) or it is more than
* INT32_MAX nanoseconds ahead, we still use INT32_MAX
* nanoseconds.
*/
if ((deadline < 0) || (deadline > INT32_MAX)) {
deadline = INT32_MAX;
}
return icount_round(deadline);
} else {
return replay_get_instructions();
}
}
static void icount_notify_aio_contexts(void)
{
/* Wake up other AioContexts. */
qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
qemu_clock_run_timers(QEMU_CLOCK_VIRTUAL);
}
void icount_handle_deadline(void)
{
assert(qemu_in_vcpu_thread());
int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
QEMU_TIMER_ATTR_ALL);
/*
* Instructions, interrupts, and exceptions are processed in cpu-exec.
* Don't interrupt cpu thread, when these events are waiting
* (i.e., there is no checkpoint)
*/
if (deadline == 0) {
icount_notify_aio_contexts();
}
}
/* Distribute the budget evenly across all CPUs */
int64_t icount_percpu_budget(int cpu_count)
{
int64_t limit = icount_get_limit();
int64_t timeslice = limit / cpu_count;
if (timeslice == 0) {
timeslice = limit;
}
return timeslice;
}
void icount_prepare_for_run(CPUState *cpu, int64_t cpu_budget)
{
int insns_left;
/*
* These should always be cleared by icount_process_data after
* each vCPU execution. However u16.high can be raised
* asynchronously by cpu_exit/cpu_interrupt/tcg_handle_interrupt
*/
g_assert(cpu->neg.icount_decr.u16.low == 0);
g_assert(cpu->icount_extra == 0);
replay_mutex_lock();
cpu->icount_budget = MIN(icount_get_limit(), cpu_budget);
insns_left = MIN(0xffff, cpu->icount_budget);
cpu->neg.icount_decr.u16.low = insns_left;
cpu->icount_extra = cpu->icount_budget - insns_left;
if (cpu->icount_budget == 0) {
/*
* We're called without the BQL, so must take it while
* we're calling timer handlers.
*/
bql_lock();
icount_notify_aio_contexts();
bql_unlock();
}
}
void icount_process_data(CPUState *cpu)
{
/* Account for executed instructions */
icount_update(cpu);
/* Reset the counters */
cpu->neg.icount_decr.u16.low = 0;
cpu->icount_extra = 0;
cpu->icount_budget = 0;
replay_account_executed_instructions();
replay_mutex_unlock();
}
void icount_handle_interrupt(CPUState *cpu, int mask)
{
int old_mask = cpu->interrupt_request;
tcg_handle_interrupt(cpu, mask);
if (qemu_cpu_is_self(cpu) &&
!cpu->neg.can_do_io
&& (mask & ~old_mask) != 0) {
cpu_abort(cpu, "Raised interrupt while not in I/O function");
}
}
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