On Tue, Oct 17, 2023 at 8:52 AM Sebastian Ott <sebott@xxxxxxxxxx> wrote:
>
> On Mon, 9 Oct 2023, Raghavendra Rao Ananta wrote:
> > +static int set_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
> > + u64 val)
> > +{
> > + struct kvm *kvm = vcpu->kvm;
> > + u64 new_n, mutable_mask;
> > +
> > + mutex_lock(&kvm->arch.config_lock);
> > +
> > + /*
> > + * Make PMCR immutable once the VM has started running, but do
> > + * not return an error (-EBUSY) to meet the existing expectations.
> > + */
>
> Why should we mention which error we're _not_ returning?
>
Oh, it's not to break the existing userspace expectations. Before this
series, any 'write' from userspace was possible. Returning -EBUSY all
of a sudden might tamper with this expectation.
Thank you.
Raghavendra
>
> > + if (kvm_vm_has_ran_once(vcpu->kvm)) {
> > + mutex_unlock(&kvm->arch.config_lock);
> > + return 0;
> > + }
>
