Re: [PATCH 6/8] hvf: Use OS provided vcpu kick function

[Alexander Graf]

On 26.11.20 23:18, Eduardo Habkost wrote:
> On Thu, Nov 26, 2020 at 10:50:15PM +0100, Alexander Graf wrote:
> > When kicking another vCPU, we get an OS function that explicitly does that for 
> > us
> > on Apple Silicon. That works better than the current signaling logic, let's make
> > use of it there.
> >
> > Signed-off-by: Alexander Graf <agraf@csgraf.de>
> > ---
> >   accel/hvf/hvf-cpus.c | 12 ++++++++++++
> >   1 file changed, 12 insertions(+)
> >
> > diff --git a/accel/hvf/hvf-cpus.c b/accel/hvf/hvf-cpus.c
> > index b9f674478d..74a272d2e8 100644
> > --- a/accel/hvf/hvf-cpus.c
> > +++ b/accel/hvf/hvf-cpus.c
> > @@ -418,8 +418,20 @@ static void hvf_start_vcpu_thread(CPUState *cpu)
> >                          cpu, QEMU_THREAD_JOINABLE);
> >   }
> >   
> > +#ifdef __aarch64__
> > +static void hvf_kick_vcpu_thread(CPUState *cpu)
> > +{
> > +    if (!qemu_cpu_is_self(cpu)) {
> > +        hv_vcpus_exit(&cpu->hvf_fd, 1);
> > +    }
> > +}
> > +#endif
> > +
> >   static const CpusAccel hvf_cpus = {
> >       .create_vcpu_thread = hvf_start_vcpu_thread,
> > +#ifdef __aarch64__
> > +    .kick_vcpu_thread = hvf_kick_vcpu_thread,
> > +#endif
> Interesting.  We have considered the possibility of adding
> arch-specific TYPE_ACCEL subclasses when discussing Claudio's,
> series.  Here we have another arch-specific hack that could be
> avoided if we had a TYPE_ARM_HVF_ACCEL QOM class.


I don't think that's necessary in this case. I don't see how you could 
ever have aarch64 and x86 HVF backends compiled into the same binary. 
The header files even have a lot of #ifdef's.

Either way, I've changed it to a weak function in v2. That way it's a 
bit easier to read.


Alex