On Fri, Apr 29, 2022 at 7:12 PM Peter Gonda <pgonda@xxxxxxxxxx> wrote:
> Sounds good. Instead of doing this prev_vcpu solution we could just
> keep the 1st vcpu for source and target. I think this could work since
> all the vcpu->mutex.dep_maps do not point to the same string.
>
> Lock:
> bool acquired = false;
> kvm_for_each_vcpu(...) {
> if (mutex_lock_killable_nested(&vcpu->mutex, role)
> goto out_unlock;
> acquired = true;
> if (acquired)
> mutex_release(&vcpu->mutex, role)
> }
Almost:
bool first = true;
kvm_for_each_vcpu(...) {
if (mutex_lock_killable_nested(&vcpu->mutex, role)
goto out_unlock;
if (first)
++role, first = false;
else
mutex_release(&vcpu->mutex, role);
}
and to unlock:
bool first = true;
kvm_for_each_vcpu(...) {
if (first)
first = false;
else
mutex_acquire(&vcpu->mutex, role);
mutex_unlock(&vcpu->mutex);
acquired = false;
}
because you cannot use the first vCPU's role again when locking.
Paolo
