On Tue 10. Dec 2024 at 10:21, Roman Bolshakov <rbolsha...@ddn.com> wrote:
> On 10.12.2024 04:22, Philippe Mathieu-Daudé wrote:
> > On 9/12/24 21:36, p...@philjordan.eu wrote:
> >> From: Phil Dennis-Jordan <p...@philjordan.eu>
> >>
> >> This seems to be entirely superfluous and is costly enough to show up in
> >
> > So the pthread_kill(cpu->thread, SIG_IPI) is entirely superfluous?
> >
> >> profiling. hv_vcpu_interrupt() has been demonstrated to very reliably
> >> cause VM exits - even if the target vCPU isn't even running, it will
> >> immediately exit on entry.
> >>
> >> Signed-off-by: Phil Dennis-Jordan <p...@philjordan.eu>
> >> ---
> >> target/i386/hvf/hvf.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/target/i386/hvf/hvf.c b/target/i386/hvf/hvf.c
> >> index 3b6ee79fb2..936c31dbdd 100644
> >> --- a/target/i386/hvf/hvf.c
> >> +++ b/target/i386/hvf/hvf.c
> >> @@ -214,7 +214,7 @@ static inline bool
> >> apic_bus_freq_is_known(CPUX86State *env)
> >> void hvf_kick_vcpu_thread(CPUState *cpu)
> >> {
> >> - cpus_kick_thread(cpu);
> >> + cpu->thread_kicked = true;
> >> hv_vcpu_interrupt(&cpu->accel->fd, 1);
> >> }
> >
> SIG_IPI is macOS crutch handled in XNU kernel that was essential until
> Phil submitted proper kick support with hv_vcpu_interrupt().
>
> Ah yes, perhaps it allowed exit from hv_vcpu_run(). hv_vcpu_run_until()
definitely does not exit early upon receiving SIG_IPI (USR1).
