Re: [PATCH 2/3] hvf: implement guest debugging on Apple Silicon hosts

[Francesco Cagnin <francesco.cagnin@gmail.com>]

Mads, thanks for the review and feedbacks. I worked on this a few months
ago but only managed to have it published now, I'm sorry for work being
done twice.

I'll add support for SSTEP_NOIRQ as you suggested.

For multi-core systems there's no particular issue, just I'm not
familiar with all of these topics and I'm asking for good practices. KVM
saves breakpoints information in struct 'KVMState', and following the
same approach I've updated struct 'HVFState' to store equivalent data.
To keep separate information for each cpu, KVM uses field 'kvm_state' in
struct 'CPUState' (see 'include/hw/core/cpu.h'), but at the moment
there's no analogous field for the HVF state (which is instead defined
as a single global variable in 'accel/hvf/hvf-accel-ops.c'). Should we
add a new field to 'CPUState' for the HVF state, or take a different
approach?

For your last question regarding `hv_vcpu_set_trap_debug_exceptions()`,
I think it's possible to move it to `hvf_arch_update_guest_debug()` but
I'm not confident about `hvf_arch_init_vcpu()`, I will experiment again.