Re: [PATCH] KVM: Defer remote tlb flushes on invlpg (v2)

[Marcelo Tosatti <mtosatti@redhat.com>]

On Mon, Mar 16, 2009 at 01:07:50PM +0200, Avi Kivity wrote:
> KVM flushes tlbs on remote cpus for two purposes: to protect guest pages
> that it needs to collect information about, and to prevent stale tlb entries
> from pointing to pages that no longer belong to the guest.
> 
> We can defer the latter flushes to the point when we actually free the pages,
> which is during an mmu notifier invocation.  To this end, we add a new state
> remote_tlbs_dirty which marks whether the guest tlb might be inconsistent
> with the the shadow page tables.  Whenever we do a conditional flush of
> remote tlbs, we check this state, and if the remote tlbs are dirty we flush
> them to ensure no inconsistency.
> 
> [v2: add help kvm_flush_remote_tlbs_cond() to remove the need for callers
>      to care about the new logic]

Looks good, but Andrea should ack.