On Wed, Feb 15, 2023, Marc Zyngier wrote:
> On Wed, 15 Feb 2023 01:16:11 +0000, Anish Moorthy <amoorthy@xxxxxxxxxx> wrote:
> > 8. Other capabilities.
> > ======================
> >
> > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> > index 109b18e2789c4..9352e7f8480fb 100644
> > --- a/include/linux/kvm_host.h
> > +++ b/include/linux/kvm_host.h
> > @@ -801,6 +801,9 @@ struct kvm {
> > bool vm_bugged;
> > bool vm_dead;
> >
> > + rwlock_t mem_fault_nowait_lock;
> > + bool mem_fault_nowait;
>
> A full-fat rwlock to protect a single bool? What benefits do you
> expect from a rwlock? Why is it preferable to an atomic access, or a
> simple bitop?
There's no need to have any kind off dedicated atomicity. The only readers are
in vCPU context, just disallow KVM_CAP_MEM_FAULT_NOWAIT after vCPUs are created.
