On Fri, Aug 8, 2025 at 11:21 PM Philippe Mathieu-Daudé
<phi...@linaro.org> wrote:
> > diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
> > index 1a973596d87..b9da2e3770e 100644
> > --- a/accel/tcg/cpu-exec.c
> > +++ b/accel/tcg/cpu-exec.c
> > @@ -750,6 +750,7 @@ static inline bool cpu_handle_exception(CPUState *cpu,
> > int *ret)
> >
> > void tcg_kick_vcpu_thread(CPUState *cpu)
> > {
> > +#ifdef CONFIG_SYSTEM
> > /*
> > * Ensure cpu_exec will see the reason why the exit request was set.
> > * FIXME: this is not always needed. Other accelerators instead
> > @@ -757,6 +758,7 @@ void tcg_kick_vcpu_thread(CPUState *cpu)
> > * CPU thread; see kvm_arch_pre_run() for example.
> > */
> > qatomic_store_release(&cpu->exit_request, 1);
> > +#endif
> >
> > /* Ensure cpu_exec will see the exit request after TCG has exited. */
> > qatomic_store_release(&cpu->neg.icount_decr.u16.high, -1);
>
> What about cpu_handle_interrupt()?
The point of this patch isn't that qemu-user never reads exit_request
(as you point out, it does). The point is that qemu-user always uses
cpu_exit() rather than qemu_cpu_kick(), and therefore it's already
always writing exit_request.
For system emulation, writing cpu->exit_request should be moved from
tcg_kick_vcpu_thread to tcg_ops->cpu_exec_interrupt.
Paolo
Paolo
