[PATCH] KVM: arm64: Hold kvm->mmu_lock while initialising vcpu->arch.vncr_tlb

[Yosry Ahmed]

> > If yes, I think the code looks confusing, at least to a layman like
> > myself. It initially seems like the lock protects against concurrent
> > initializations, but then the NULL check is not done again under the
> > lock. The goal of the lock is not clear without the original report.
> >
> > Mayeb it's clearer to explicitly use barriers if the goal is preventing
> > reordering?
>
> This would require both the initialisation of vncr_tlb to use a store
> release, *and* all the other call sites to use a load acquire.
>
> I really don't think it is worth the churn, nor the (very small)
> burden on the readers.

That's fair. I was mainly just pointing out my initial confusion and
that others may share it. Avoiding the churn on the readers' side is
understandable. Maybe a comment here would help explain why the lock
needs to be held?