On 27.08.2025 23:21, Mykola Kvach wrote:
> --- a/xen/common/domain.c
> +++ b/xen/common/domain.c
> @@ -1349,16 +1349,10 @@ int domain_shutdown(struct domain *d, u8 reason)
> return 0;
> }
>
> -void domain_resume(struct domain *d)
> +static void domain_resume_nopause(struct domain *d)
> {
> struct vcpu *v;
>
> - /*
> - * Some code paths assume that shutdown status does not get reset under
> - * their feet (e.g., some assertions make this assumption).
> - */
> - domain_pause(d);
> -
> spin_lock(&d->shutdown_lock);
>
> d->is_shutting_down = d->is_shut_down = 0;
> @@ -1366,13 +1360,40 @@ void domain_resume(struct domain *d)
>
> for_each_vcpu ( d, v )
> {
> + /*
> + * No need to conditionally clear _VPF_suspended here:
> + * - This bit is only set on Arm, and only after a successful
> suspend.
How likely do you think it is that, if e.g. RISC-V or PPC clone Arm's
code, this comment would then be updated accordingly? IOW I don't think
a justification like this one should be written in such terms.
> + * - domain_resume_nopause() may also be called from paths other than
> + * the suspend/resume flow, such as "soft-reset" actions (e.g.,
> + * on_poweroff), as part of the Xenstore control/shutdown protocol.
> + * These require guest acknowledgement to complete the operation.
I'm having trouble connecting "require guest acknowledgement" to ...
> + * So clearing the bit unconditionally is safe.
... the safety of the unconditional clearing.
> + */
> + clear_bit(_VPF_suspended, &v->pause_flags);
> +
> if ( v->paused_for_shutdown )
> vcpu_unpause(v);
> v->paused_for_shutdown = 0;
> }
>
> spin_unlock(&d->shutdown_lock);
> +}
>
> +#ifdef CONFIG_ARM
> +void domain_resume_nopause_helper(struct domain *d)
This is an odd name to use from code meaning to invoke domain_resume_nopause().
Why isn't this called domain_resume_nopause(), and ...
> +{
> + domain_resume_nopause(d);
... the static function simply _domain_resume_nopause() (in full accordance
to the C standard's naming rules)?
> +}
> +#endif
> +
> +void domain_resume(struct domain *d)
> +{
> + /*
> + * Some code paths assume that shutdown status does not get reset under
> + * their feet (e.g., some assertions make this assumption).
> + */
> + domain_pause(d);
As you move the comment - no such assumptions exist when the code path
through domain_resume_nopause_helper() is taken?
Jan
