From: Pavel Dovgalyuk <[email protected]> This patch adds check to break cpu loop when icount expires without setting the TB_EXIT_ICOUNT_EXPIRED flag. It happens when there is no available translated blocks and all instructions were executed. In icount replay mode unnecessary tb_find will be called (which may cause an exception) and execution will be non-deterministic. Because cpu_loop_exec_tb cannot longjmp anymore, we can remove the anticipated call to align_clocks in cpu_loop_exec_tb, as well as the SyncClocks *sc argument.
Signed-off-by: Pavel Dovgalyuk <[email protected]> Message-Id: <002801d2810f$18809c20$4981d460$@ru> Signed-off-by: Paolo Bonzini <[email protected]> --- cpu-exec.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/cpu-exec.c b/cpu-exec.c index 6fd3f47..2a0dfb0 100644 --- a/cpu-exec.c +++ b/cpu-exec.c @@ -554,8 +554,9 @@ static inline bool cpu_handle_interrupt(CPUState *cpu, qemu_mutex_unlock_iothread(); } - - if (unlikely(atomic_read(&cpu->exit_request) || replay_has_interrupt())) { + /* Finally, check if we need to exit to the main loop. */ + if (unlikely(atomic_read(&cpu->exit_request) + || (use_icount && cpu->icount_decr.u16.low + cpu->icount_extra == 0))) { atomic_set(&cpu->exit_request, 0); cpu->exception_index = EXCP_INTERRUPT; return true; @@ -565,8 +566,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu, } static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb, - TranslationBlock **last_tb, int *tb_exit, - SyncClocks *sc) + TranslationBlock **last_tb, int *tb_exit) { uintptr_t ret; int32_t insns_left; @@ -615,10 +615,7 @@ static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb, */ if (insns_left > 0) { cpu_exec_nocache(cpu, insns_left, tb, false); - align_clocks(sc, cpu); } - cpu->exception_index = EXCP_INTERRUPT; - cpu_loop_exit(cpu); } #endif } @@ -593,7 +592,7 @@ int cpu_exec(CPUState *cpu) { CPUClass *cc = CPU_GET_CLASS(cpu); int ret; - SyncClocks sc; + SyncClocks sc = { 0 }; /* replay_interrupt may need current_cpu */ current_cpu = cpu; @@ -677,7 +674,7 @@ int cpu_exec(CPUState *cpu) while (!cpu_handle_interrupt(cpu, &last_tb)) { TranslationBlock *tb = tb_find(cpu, last_tb, tb_exit); - cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit, &sc); + cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit); /* Try to align the host and virtual clocks if the guest is in advance */ align_clocks(&sc, cpu); -- 2.9.3
