On Fri, Feb 07, 2020 at 04:34:10PM +0000, Marc Zyngier wrote:
> Accessing a per-cpu variable only makes sense when preemption is
> disabled (and the kernel does check this when the right debug options
> are switched on).
>
> For kvm_get_running_vcpu(), it is fine to return the value after
> re-enabling preemption, as the preempt notifiers will make sure that
> this is kept consistent across task migration (the comment above the
> function hints at it, but lacks the crucial preemption management).
>
> While we're at it, move the comment from the ARM code, which explains
> why the whole thing works.
>
> Fixes: 7495e22bb165 ("KVM: Move running VCPU from ARM to common code").
> Cc: Peter Xu <peterx@xxxxxxxxxx>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Reported-by: Zenghui Yu <yuzenghui@xxxxxxxxxx>
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> Link: https://lore.kernel.org/r/318984f6-bc36-33a3-abc6-bf2295974b06@xxxxxxxxxx
Reviewed-by: Peter Xu <peterx@xxxxxxxxxx>
--
Peter Xu
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