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accel/tcg: Restrict cpu_handle_halt() to sysemu

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Commit 372579427a5 ("tcg: enable thread-per-vCPU") added the following
comment describing EXCP_HALTED in qemu_tcg_cpu_thread_fn():

    case EXCP_HALTED:
         /* during start-up the vCPU is reset and the thread is
          * kicked several times. If we don't ensure we go back
          * to sleep in the halted state we won't cleanly
          * start-up when the vCPU is enabled.
          *
          * cpu->halted should ensure we sleep in wait_io_event
          */
         g_assert(cpu->halted);
         break;

qemu_wait_io_event() is sysemu-specific, so we can restrict the
cpu_handle_halt() call in cpu_exec() to system emulation.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210912172731.789788-2-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Philippe Mathieu-Daudé 2021-09-12 19:27:02 +02:00 committed by Richard Henderson
parent 8b1d5b3c35
commit 0596fa11f1
1 changed files with 4 additions and 2 deletions
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6
accel/tcg/cpu-exec.c
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@ -588,8 +588,9 @@ static inline void tb_add_jump(TranslationBlock *tb, int n,
static inline bool cpu_handle_halt(CPUState *cpu) static inline bool cpu_handle_halt(CPUState *cpu)
{ {
#ifndef CONFIG_USER_ONLY
if (cpu->halted) { if (cpu->halted) {
#if defined(TARGET_I386) && !defined(CONFIG_USER_ONLY) #if defined(TARGET_I386)
if (cpu->interrupt_request & CPU_INTERRUPT_POLL) { if (cpu->interrupt_request & CPU_INTERRUPT_POLL) {
X86CPU *x86_cpu = X86_CPU(cpu); X86CPU *x86_cpu = X86_CPU(cpu);
qemu_mutex_lock_iothread(); qemu_mutex_lock_iothread();
@ -597,13 +598,14 @@ static inline bool cpu_handle_halt(CPUState *cpu)
cpu_reset_interrupt(cpu, CPU_INTERRUPT_POLL); cpu_reset_interrupt(cpu, CPU_INTERRUPT_POLL);
qemu_mutex_unlock_iothread(); qemu_mutex_unlock_iothread();
} }
#endif #endif /* TARGET_I386 */
if (!cpu_has_work(cpu)) { if (!cpu_has_work(cpu)) {
return true; return true;
} }
cpu->halted = 0; cpu->halted = 0;
} }
#endif /* !CONFIG_USER_ONLY */
return false; return false;
} }