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accel/tcg: Remove check_tcg_memory_orders_compatible

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We now issue host memory barriers to match the guest memory order.
Continue to disable MTTCG only if the guest has not been ported.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2022-03-03 15:57:27 +00:00
parent f86e8f3d13
commit 97e1576957
1 changed files with 10 additions and 29 deletions
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39
accel/tcg/tcg-all.c
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@ -64,37 +64,23 @@ DECLARE_INSTANCE_CHECKER(TCGState, TCG_STATE,
* they can set the appropriate CONFIG flags in ${target}-softmmu.mak
*
* Once a guest architecture has been converted to the new primitives
* there are two remaining limitations to check.
*
* - The guest can't be oversized (e.g. 64 bit guest on 32 bit host)
* - The host must have a stronger memory order than the guest
*
* It may be possible in future to support strong guests on weak hosts
* but that will require tagging all load/stores in a guest with their
* implicit memory order requirements which would likely slow things
* down a lot.
* there is one remaining limitation to check:
* - The guest can't be oversized (e.g. 64 bit guest on 32 bit host)
*/
static bool check_tcg_memory_orders_compatible(void)
{
#if defined(TCG_GUEST_DEFAULT_MO) && defined(TCG_TARGET_DEFAULT_MO)
return (TCG_GUEST_DEFAULT_MO & ~TCG_TARGET_DEFAULT_MO) == 0;
#else
return false;
#endif
}
static bool default_mttcg_enabled(void)
{
if (icount_enabled() || TCG_OVERSIZED_GUEST) {
return false;
} else {
#ifdef TARGET_SUPPORTS_MTTCG
return check_tcg_memory_orders_compatible();
#else
return false;
#endif
}
#ifdef TARGET_SUPPORTS_MTTCG
# ifndef TCG_GUEST_DEFAULT_MO
# error "TARGET_SUPPORTS_MTTCG without TCG_GUEST_DEFAULT_MO"
# endif
return true;
#else
return false;
#endif
}
static void tcg_accel_instance_init(Object *obj)
@ -162,11 +148,6 @@ 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
if (!check_tcg_memory_orders_compatible()) {
warn_report("Guest expects a stronger memory ordering "
"than the host provides");
error_printf("This may cause strange/hard to debug errors\n");
}
s->mttcg_enabled = true;
}
} else if (strcmp(value, "single") == 0) {