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tcg: move qemu_tcg_configure to accel/tcg/tcg-all.c

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Move everything related to mttcg_enabled in accel/tcg/tcg-all.c,
which will make even more sense when "thread" becomes a QOM property.

For now, initializing mttcg_enabled in the instance_init function
prepares for the next patch, which will only invoke qemu_tcg_configure
when the command line includes a -accel option.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2019-11-14 10:40:27 +01:00
parent 7f8b6126e7
commit af0440ae85
2 changed files with 83 additions and 72 deletions
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83
accel/tcg/tcg-all.c
View File

@ -30,6 +30,11 @@
#include "cpu.h"
#include "sysemu/cpus.h"
#include "qemu/main-loop.h"
#include "tcg/tcg.h"
#include "include/qapi/error.h"
#include "include/qemu/error-report.h"
#include "include/hw/boards.h"
#include "qemu/option.h"
unsigned long tcg_tb_size;
@ -58,6 +63,53 @@ static void tcg_handle_interrupt(CPUState *cpu, int mask)
}
}
/*
* 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 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.
*/
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 (use_icount || TCG_OVERSIZED_GUEST) {
return false;
} else {
#ifdef TARGET_SUPPORTS_MTTCG
return check_tcg_memory_orders_compatible();
#else
return false;
#endif
}
}
static void tcg_accel_instance_init(Object *obj)
{
mttcg_enabled = default_mttcg_enabled();
}
static int tcg_init(MachineState *ms)
{
tcg_exec_init(tcg_tb_size * 1024 * 1024);
@ -65,6 +117,36 @@ static int tcg_init(MachineState *ms)
return 0;
}
void qemu_tcg_configure(QemuOpts *opts, Error **errp)
{
const char *t = qemu_opt_get(opts, "thread");
if (!t) {
return;
}
if (strcmp(t, "multi") == 0) {
if (TCG_OVERSIZED_GUEST) {
error_setg(errp, "No MTTCG when guest word size > hosts");
} else if (use_icount) {
error_setg(errp, "No MTTCG when icount is enabled");
} else {
#ifndef TARGET_SUPPORTS_MTTCG
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");
}
mttcg_enabled = true;
}
} else if (strcmp(t, "single") == 0) {
mttcg_enabled = false;
} else {
error_setg(errp, "Invalid 'thread' setting %s", t);
}
}
static void tcg_accel_class_init(ObjectClass *oc, void *data)
{
AccelClass *ac = ACCEL_CLASS(oc);
@ -78,6 +160,7 @@ static void tcg_accel_class_init(ObjectClass *oc, void *data)
static const TypeInfo tcg_accel_type = {
.name = TYPE_TCG_ACCEL,
.parent = TYPE_ACCEL,
.instance_init = tcg_accel_instance_init,
.class_init = tcg_accel_class_init,
};

72
cpus.c
View File

@ -166,78 +166,6 @@ typedef struct TimersState {
static TimersState timers_state;
bool mttcg_enabled;
/*
* 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 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.
*/
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 (use_icount || TCG_OVERSIZED_GUEST) {
return false;
} else {
#ifdef TARGET_SUPPORTS_MTTCG
return check_tcg_memory_orders_compatible();
#else
return false;
#endif
}
}
void qemu_tcg_configure(QemuOpts *opts, Error **errp)
{
const char *t = qemu_opt_get(opts, "thread");
if (t) {
if (strcmp(t, "multi") == 0) {
if (TCG_OVERSIZED_GUEST) {
error_setg(errp, "No MTTCG when guest word size > hosts");
} else if (use_icount) {
error_setg(errp, "No MTTCG when icount is enabled");
} else {
#ifndef TARGET_SUPPORTS_MTTCG
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");
}
mttcg_enabled = true;
}
} else if (strcmp(t, "single") == 0) {
mttcg_enabled = false;
} else {
error_setg(errp, "Invalid 'thread' setting %s", t);
}
} else {
mttcg_enabled = default_mttcg_enabled();
}
}
/* The current number of executed instructions is based on what we
* originally budgeted minus the current state of the decrementing