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accel/tcg: Use one_insn_per_tb global instead of old singlestep global

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The only place left that looks at the old 'singlestep' global
variable is the TCG curr_cflags() function.  Replace the old global
with a new 'one_insn_per_tb' which is defined in tcg-all.c and
declared in accel/tcg/internal.h.  This keeps it restricted to the
TCG code, unlike 'singlestep' which was available to every file in
the system and defined in multiple different places for softmmu vs
linux-user vs bsd-user.

While we're making this change, use qatomic_read() and qatomic_set()
on the accesses to the new global, because TCG will read it without
holding a lock.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20230417164041.684562-4-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2023-04-17 17:40:34 +01:00
parent 93cbd6c91d
commit 0e33928cd9
7 changed files with 7 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
accel/tcg/cpu-exec.c
View file

@ -159,7 +159,7 @@ uint32_t curr_cflags(CPUState *cpu)
*/
if (unlikely(cpu->singlestep_enabled)) {
cflags |= CF_NO_GOTO_TB | CF_NO_GOTO_PTR | CF_SINGLE_STEP | 1;
} else if (singlestep) {
} else if (qatomic_read(&one_insn_per_tb)) {
cflags |= CF_NO_GOTO_TB | 1;
} else if (qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
cflags |= CF_NO_GOTO_TB;

2
accel/tcg/internal.h
View file

@ -67,4 +67,6 @@ static inline target_ulong log_pc(CPUState *cpu, const TranslationBlock *tb)
extern int64_t max_delay;
extern int64_t max_advance;
extern bool one_insn_per_tb;
#endif /* ACCEL_TCG_INTERNAL_H */

6
accel/tcg/tcg-all.c
View file

@ -31,6 +31,7 @@
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "qemu/accel.h"
#include "qemu/atomic.h"
#include "qapi/qapi-builtin-visit.h"
#include "qemu/units.h"
#if !defined(CONFIG_USER_ONLY)
@ -110,6 +111,7 @@ static void tcg_accel_instance_init(Object *obj)
}
bool mttcg_enabled;
bool one_insn_per_tb;
static int tcg_init_machine(MachineState *ms)
{
@ -219,8 +221,8 @@ static void tcg_set_one_insn_per_tb(Object *obj, bool value, Error **errp)
{
TCGState *s = TCG_STATE(obj);
s->one_insn_per_tb = value;
/* For the moment, set the global also: this changes the behaviour */
singlestep = value;
/* Set the global also: this changes the behaviour */
qatomic_set(&one_insn_per_tb, value);
}
static int tcg_gdbstub_supported_sstep_flags(void)

1
bsd-user/main.c
View file

@ -49,7 +49,6 @@
#include "host-os.h"
#include "target_arch_cpu.h"
int singlestep;
static bool opt_one_insn_per_tb;
uintptr_t guest_base;
bool have_guest_base;

2
include/exec/cpu-common.h
View file

@ -163,8 +163,6 @@ int cpu_memory_rw_debug(CPUState *cpu, vaddr addr,
void *ptr, size_t len, bool is_write);
/* vl.c */
extern int singlestep;
void list_cpus(void);
#endif /* CPU_COMMON_H */

1
linux-user/main.c
View file

@ -68,7 +68,6 @@
char *exec_path;
char real_exec_path[PATH_MAX];
int singlestep;
static bool opt_one_insn_per_tb;
static const char *argv0;
static const char *gdbstub;

1
softmmu/globals.c
View file

@ -43,7 +43,6 @@ int vga_interface_type = VGA_NONE;
bool vga_interface_created;
Chardev *parallel_hds[MAX_PARALLEL_PORTS];
int win2k_install_hack;
int singlestep;
int fd_bootchk = 1;
int graphic_rotate;
QEMUOptionRom option_rom[MAX_OPTION_ROMS];