From mboxrd@z Thu Jan  1 00:00:00 1970
From: Takuya Yoshikawa <takuya.yoshikawa@gmail.com>
Subject: Re: [PATCH 1/2] KVM: MMU: Mark sp mmio cached when creating mmio
 spte
Date: Wed, 13 Mar 2013 22:40:56 +0900
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Cc: Gleb Natapov <gleb@redhat.com>,
	Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>,
	mtosatti@redhat.com, kvm@vger.kernel.org
To: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
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On Wed, 13 Mar 2013 20:42:41 +0800
Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> wrote:

> >>>> How about save all mmio spte into a mmio-rmap?
> >>>
> >>> The problem is that other mmu code would need to care about the pointers
> >>> stored in the new rmap list: when mmu_shrink zaps shadow pages for example.
> >>
> >> It is not hard... all the codes have been wrapped by *zap_spte*.
> >>
> > So are you going to send a patch? What do you think about applying this
> > as temporary solution?
> 
> Hi Gleb,
> 
> Since it only needs small change based on this patch, I think we can directly
> apply the rmap-based way.
> 
> Takuya, could you please do this? ;)

Though I'm fine with my making the patch better, I'm still thinking
about the bad side of it, though.

In zap_spte, don't we need to search the pointer to be removed from the
global mmio-rmap list?  How long can that list be?

Implementing it will/may not be difficult but I'm not sure if we would
get pure improvement.  Unless it becomes 99% sure, I think we should
first take a basic approach.

What do you think?

Thanks,
	Takuya