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