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

[Mads Ynddal]

> On 4 Nov 2022, at 19.41, francesco.cagnin@gmail.com wrote:
> 
> From: Francesco Cagnin <fcagnin@quarkslab.com>
> 
> Support is added for single-stepping, software breakpoints, hardware
> breakpoints and watchpoints. The code has been structured like the KVM
> counterpart (and many parts are basically identical).
> 
> Guests can be debugged through the gdbstub.
> 
> Signed-off-by: Francesco Cagnin <fcagnin@quarkslab.com>
> ---
> accel/hvf/hvf-accel-ops.c | 124 ++++++++++++++++++++++++
> accel/hvf/hvf-all.c       |  24 +++++
> cpu.c                     |   3 +
> include/sysemu/hvf.h      |  29 ++++++
> include/sysemu/hvf_int.h  |   1 +
> target/arm/hvf/hvf.c      | 194 +++++++++++++++++++++++++++++++++++++-
> 6 files changed, 374 insertions(+), 1 deletion(-)
> 
> diff --git a/include/sysemu/hvf.h b/include/sysemu/hvf.h
> index bb70082e45..3e99c80416 100644
> --- a/include/sysemu/hvf.h
> +++ b/include/sysemu/hvf.h
> @@ -1180,6 +1201,9 @@ int hvf_vcpu_exec(CPUState *cpu)
> 
>     flush_cpu_state(cpu);
> 
> +    r = hv_vcpu_set_trap_debug_exceptions(cpu->hvf->fd, 
> trap_debug_exceptions);
> +    assert_hvf_ok(r);
> +
>     qemu_mutex_unlock_iothread();
>     assert_hvf_ok(hv_vcpu_run(cpu->hvf->fd));

We don't need to set this at every call to `hvf_vcpu_exec`. Would it make sense
to move it to `hvf_arch_update_guest_debug` or even `hvf_arch_init_vcpu`?

(CC'ed Alex Bennée as we discussed the GDB stub in HVF at KVM Forum 2022)