From mboxrd@z Thu Jan  1 00:00:00 1970
From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Subject: Re: KVM: MMU: drop read-only large sptes when creating lower level
 sptes
Date: Tue, 25 Feb 2014 11:30:37 +0800
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References: <20140224165932.GA15971@amt.cnet>
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Cc: Paolo Bonzini <pbonzini@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>,
	kvm-devel <kvm@vger.kernel.org>
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On 02/25/2014 12:59 AM, Marcelo Tosatti wrote:
> 
> Read-only large sptes can be created due to read-only faults as
> follows:
> 
> - QEMU pagetable entry that maps guest memory is read-only 
> due to COW.
> - Guest read faults such memory, COW is not broken, because
> it is a read-only fault.
> - Enable dirty logging, large spte not nuked because it is read-only.
> - Write-fault on such memory causes guest to loop endlessly
> (which must go down to level 1 because dirty logging is enabled).

Hi Marcelo,

It surprised me that the large-readonly mapping was not dropped
by mmu-notifer as this is write fault on readonly mapping in Qemu.
Hmm... i missed something?