From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [patch 4/4] KVM: MMU: pinned sps are not candidates for deletion.
Date: Mon, 22 Sep 2014 14:17:46 -0300
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To: Xiao Guangrong <xiaoguangrong.eric@gmail.com>,
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On Tue, Sep 09, 2014 at 12:41:27PM -0300, Marcelo Tosatti wrote:
> On Tue, Jul 22, 2014 at 05:59:42AM +0800, Xiao Guangrong wrote:
> > 
> > On Jul 10, 2014, at 3:12 AM, mtosatti@redhat.com wrote:
> > 
> > > Skip pinned shadow pages when selecting pages to zap.
> > 
> > It seems there is no way to prevent changing pinned spte on
> > zap-all path?
> 
> Xiao,
> 
> The way would be to reload remote mmus, forcing the vcpu to exit,
> zapping a page, then vcpu will pagefault any necessary page via
> kvm_mmu_pin_pages.
> 
> kvm_mmu_invalidate_zap_all_pages does: 
> 
> - spin_lock(mmu_lock)
> - kvm_reload_remote_mmus
> ...
> - spin_unlock(mmu_lock)
> 
> So its OK to change pinned spte on zap all path.
> 
> > I am thing if we could move pinned spte to another list (eg. pinned_shadow_pages)
> > instead of active list so that it can not be touched by any other free paths. 
> > Your idea?
> 
> As mentioned it above, it is ok to zap pinned sptes as long w 
> reload remote mmus request is performed.
> 
> That said, you still consider a separate list?
> 

Xiao, ping?