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accel/tcg: Split out tb_flush__exclusive_or_serial

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Expose a routine to be called when no cpus are running.
Simplify the do_tb_flush run_on_cpu callback, because
that is explicitly called with start_exclusive; there
is no need for the mmap_lock as well.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2025-09-05 17:57:14 +02:00
parent 9d61f61b4f
commit b773c149a8
2 changed files with 40 additions and 14 deletions
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39
accel/tcg/tb-maint.c
View file

@ -36,6 +36,9 @@
#include "internal-common.h"
#ifdef CONFIG_USER_ONLY
#include "user/page-protection.h"
#define runstate_is_running() true
#else
#include "system/runstate.h"
#endif
@ -88,7 +91,10 @@ static IntervalTreeRoot tb_root;
static void tb_remove_all(void)
{
assert_memory_lock();
/*
* Only called from tb_flush__exclusive_or_serial, where we have already
* asserted that we're in an exclusive state.
*/
memset(&tb_root, 0, sizeof(tb_root));
}
@ -756,17 +762,19 @@ static void tb_remove(TranslationBlock *tb)
}
#endif /* CONFIG_USER_ONLY */
/* flush all the translation blocks */
static void do_tb_flush(CPUState *cpu, run_on_cpu_data tb_flush_count)
/*
* Flush all the translation blocks.
* Must be called from a context in which no cpus are running,
* e.g. start_exclusive() or vm_stop().
*/
void tb_flush__exclusive_or_serial(void)
{
bool did_flush = false;
CPUState *cpu;
mmap_lock();
/* If it is already been done on request of another CPU, just retry. */
if (tb_ctx.tb_flush_count != tb_flush_count.host_int) {
goto done;
}
did_flush = true;
assert(tcg_enabled());
/* Note that cpu_in_serial_context checks cpu_in_exclusive_context. */
assert(!runstate_is_running() ||
(current_cpu && cpu_in_serial_context(current_cpu)));
CPU_FOREACH(cpu) {
tcg_flush_jmp_cache(cpu);
@ -778,11 +786,14 @@ static void do_tb_flush(CPUState *cpu, run_on_cpu_data tb_flush_count)
tcg_region_reset_all();
/* XXX: flush processor icache at this point if cache flush is expensive */
qatomic_inc(&tb_ctx.tb_flush_count);
qemu_plugin_flush_cb();
}
done:
mmap_unlock();
if (did_flush) {
qemu_plugin_flush_cb();
static void do_tb_flush(CPUState *cpu, run_on_cpu_data tb_flush_count)
{
/* If it is already been done on request of another CPU, just retry. */
if (tb_ctx.tb_flush_count == tb_flush_count.host_int) {
tb_flush__exclusive_or_serial();
}
}

15
include/exec/tb-flush.h
View file

@ -8,6 +8,21 @@
#ifndef _TB_FLUSH_H_
#define _TB_FLUSH_H_
/**
* tb_flush__exclusive_or_serial()
*
* Used to flush all the translation blocks in the system. Mostly this is
* used to empty the code generation buffer after it is full. Sometimes it
* is used when it is simpler to flush everything than work out which
* individual translations are now invalid.
*
* Must be called from an exclusive or serial context, e.g. start_exclusive,
* vm_stop, or when there is only one vcpu. Note that start_exclusive cannot
* be called from within the cpu run loop, so this cannot be called from
* within target code.
*/
void tb_flush__exclusive_or_serial(void);
/**
* tb_flush() - flush all translation blocks
* @cs: CPUState (must be valid, but treated as anonymous pointer)