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tcg: Convert TCGState::mttcg_enabled to TriState

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Use the OnOffAuto type as 3-state.

Since the TCGState instance is zero-initialized, the
mttcg_enabled is initialzed as AUTO (ON_OFF_AUTO_AUTO).

In tcg_init_machine(), if mttcg_enabled is still AUTO,
set a default value (effectively inlining the
default_mttcg_enabled() method content).

In the tcg_get_thread() getter, consider AUTO / OFF states
as "single", otherwise ON is "multi".

Reviewed-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Philippe Mathieu-Daudé 2025-04-02 16:48:24 +02:00 • committed by Richard Henderson
parent 61fc4c2bfa
commit d1aa577228
1 changed files with 36 additions and 38 deletions
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74
accel/tcg/tcg-all.c
View file

@ -32,6 +32,7 @@
#include "qemu/error-report.h"
#include "qemu/accel.h"
#include "qemu/atomic.h"
#include "qapi/qapi-types-common.h"
#include "qapi/qapi-builtin-visit.h"
#include "qemu/units.h"
#if defined(CONFIG_USER_ONLY)
@ -47,7 +48,7 @@
struct TCGState {
AccelState parent_obj;
bool mttcg_enabled;
OnOffAuto mttcg_enabled;
bool one_insn_per_tb;
int splitwx_enabled;
unsigned long tb_size;
@ -63,41 +64,14 @@ DECLARE_INSTANCE_CHECKER(TCGState, TCG_STATE,
bool qemu_tcg_mttcg_enabled(void)
{
TCGState *s = TCG_STATE(current_accel());
return s->mttcg_enabled;
return s->mttcg_enabled == ON_OFF_AUTO_ON;
}
#endif /* !CONFIG_USER_ONLY */
/*
* We default to false if we know other options have been enabled
* which are currently incompatible with MTTCG. Otherwise when each
* guest (target) has been updated to support:
* - atomic instructions
* - memory ordering primitives (barriers)
* they can set the appropriate CONFIG flags in ${target}-softmmu.mak
*
* Once a guest architecture has been converted to the new primitives
* there is one remaining limitation to check:
* - The guest can't be oversized (e.g. 64 bit guest on 32 bit host)
*/
static bool default_mttcg_enabled(void)
{
if (icount_enabled()) {
return false;
}
#ifdef TARGET_SUPPORTS_MTTCG
return true;
#else
return false;
#endif
}
static void tcg_accel_instance_init(Object *obj)
{
TCGState *s = TCG_STATE(obj);
s->mttcg_enabled = default_mttcg_enabled();
/* If debugging enabled, default "auto on", otherwise off. */
#if defined(CONFIG_DEBUG_TCG) && !defined(CONFIG_USER_ONLY)
s->splitwx_enabled = -1;
@ -113,16 +87,40 @@ static int tcg_init_machine(MachineState *ms)
TCGState *s = TCG_STATE(current_accel());
unsigned max_threads = 1;
#ifndef CONFIG_USER_ONLY
# ifdef TARGET_SUPPORTS_MTTCG
bool mttcg_supported = true;
# else
bool mttcg_supported = false;
# endif
if (s->mttcg_enabled == ON_OFF_AUTO_AUTO) {
/*
* We default to false if we know other options have been enabled
* which are currently incompatible with MTTCG. Otherwise when each
* guest (target) has been updated to support:
* - atomic instructions
* - memory ordering primitives (barriers)
* they can set the appropriate CONFIG flags in ${target}-softmmu.mak
*
* Once a guest architecture has been converted to the new primitives
* there is one remaining limitation to check:
* - The guest can't be oversized (e.g. 64 bit guest on 32 bit host)
*/
if (mttcg_supported && !icount_enabled()) {
s->mttcg_enabled = ON_OFF_AUTO_ON;
} else {
s->mttcg_enabled = ON_OFF_AUTO_OFF;
}
}
if (s->mttcg_enabled == ON_OFF_AUTO_ON) {
max_threads = ms->smp.max_cpus;
}
#endif
tcg_allowed = true;
page_init();
tb_htable_init();
#ifndef CONFIG_USER_ONLY
if (s->mttcg_enabled) {
max_threads = ms->smp.max_cpus;
}
#endif
tcg_init(s->tb_size * MiB, s->splitwx_enabled, max_threads);
#if defined(CONFIG_SOFTMMU)
@ -144,7 +142,7 @@ static char *tcg_get_thread(Object *obj, Error **errp)
{
TCGState *s = TCG_STATE(obj);
return g_strdup(s->mttcg_enabled ? "multi" : "single");
return g_strdup(s->mttcg_enabled == ON_OFF_AUTO_ON ? "multi" : "single");
}
static void tcg_set_thread(Object *obj, const char *value, Error **errp)
@ -159,10 +157,10 @@ static void tcg_set_thread(Object *obj, const char *value, Error **errp)
warn_report("Guest not yet converted to MTTCG - "
"you may get unexpected results");
#endif
s->mttcg_enabled = true;
s->mttcg_enabled = ON_OFF_AUTO_ON;
}
} else if (strcmp(value, "single") == 0) {
s->mttcg_enabled = false;
s->mttcg_enabled = ON_OFF_AUTO_OFF;
} else {
error_setg(errp, "Invalid 'thread' setting %s", value);
}