xemu/accel/tcg/tcg-accel-ops-mttcg.c
Richard Henderson 6cc9d67c6f accel/tcg: Precompute curr_cflags into cpu->tcg_cflags
The primary motivation is to remove a dozen insns along
the fast-path in tb_lookup.  As a byproduct, this allows
us to completely remove parallel_cpus.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-03-06 11:53:57 -08:00

134 lines
4.1 KiB
C

/*
* QEMU TCG Multi Threaded vCPUs implementation
*
* 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 "qemu-common.h"
#include "sysemu/tcg.h"
#include "sysemu/replay.h"
#include "qemu/main-loop.h"
#include "qemu/guest-random.h"
#include "exec/exec-all.h"
#include "hw/boards.h"
#include "tcg-accel-ops.h"
#include "tcg-accel-ops-mttcg.h"
/*
* In the multi-threaded case each vCPU has its own thread. The TLS
* variable current_cpu can be used deep in the code to find the
* current CPUState for a given thread.
*/
static void *mttcg_cpu_thread_fn(void *arg)
{
CPUState *cpu = arg;
assert(tcg_enabled());
g_assert(!icount_enabled());
rcu_register_thread();
tcg_register_thread();
qemu_mutex_lock_iothread();
qemu_thread_get_self(cpu->thread);
cpu->thread_id = qemu_get_thread_id();
cpu->can_do_io = 1;
current_cpu = cpu;
cpu_thread_signal_created(cpu);
qemu_guest_random_seed_thread_part2(cpu->random_seed);
/* process any pending work */
cpu->exit_request = 1;
do {
if (cpu_can_run(cpu)) {
int r;
qemu_mutex_unlock_iothread();
r = tcg_cpus_exec(cpu);
qemu_mutex_lock_iothread();
switch (r) {
case EXCP_DEBUG:
cpu_handle_guest_debug(cpu);
break;
case EXCP_HALTED:
/*
* during start-up the vCPU is reset and the thread is
* kicked several times. If we don't ensure we go back
* to sleep in the halted state we won't cleanly
* start-up when the vCPU is enabled.
*
* cpu->halted should ensure we sleep in wait_io_event
*/
g_assert(cpu->halted);
break;
case EXCP_ATOMIC:
qemu_mutex_unlock_iothread();
cpu_exec_step_atomic(cpu);
qemu_mutex_lock_iothread();
default:
/* Ignore everything else? */
break;
}
}
qatomic_mb_set(&cpu->exit_request, 0);
qemu_wait_io_event(cpu);
} while (!cpu->unplug || cpu_can_run(cpu));
tcg_cpus_destroy(cpu);
qemu_mutex_unlock_iothread();
rcu_unregister_thread();
return NULL;
}
void mttcg_kick_vcpu_thread(CPUState *cpu)
{
cpu_exit(cpu);
}
void mttcg_start_vcpu_thread(CPUState *cpu)
{
char thread_name[VCPU_THREAD_NAME_SIZE];
g_assert(tcg_enabled());
tcg_cpu_init_cflags(cpu, current_machine->smp.max_cpus > 1);
cpu->thread = g_malloc0(sizeof(QemuThread));
cpu->halt_cond = g_malloc0(sizeof(QemuCond));
qemu_cond_init(cpu->halt_cond);
/* create a thread per vCPU with TCG (MTTCG) */
snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/TCG",
cpu->cpu_index);
qemu_thread_create(cpu->thread, thread_name, mttcg_cpu_thread_fn,
cpu, QEMU_THREAD_JOINABLE);
#ifdef _WIN32
cpu->hThread = qemu_thread_get_handle(cpu->thread);
#endif
}