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Date: Mon, 21 May 2012 16:15:50 +0800
From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
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To: Gleb Natapov <gleb@redhat.com>
CC: Avi Kivity <avi@redhat.com>, Marcelo Tosatti <mtosatti@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
Subject: Re: [PATCH] KVM: fix async page fault working for readonly mapping
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On 05/21/2012 04:08 PM, Gleb Natapov wrote:

> On Mon, May 21, 2012 at 02:45:45PM +0800, Xiao Guangrong wrote:
>> If we map a readonly memory space from host to guest and the page is
>> not currently mapped in the host, we will get a fault-pfn and async
>> is not allowed, then the vm will crash
>>
> Why would we want to map a readonly memory space from host to guest?
> We may want to do it to support memory semantics on read and mmio on
> write, but do not right now unless something changed while I was not
> looking.


Some test cases in kvm-unit-tests and the benchmark i am writing for KVM
need map the function on host to guest.