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From: Marcelo Tosatti <mtosatti@redhat.com>
To: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Gleb Natapov <gleb@redhat.com>, Avi Kivity <avi@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
Date: Mon, 21 May 2012 16:30:41 -0300	[thread overview]
Message-ID: <20120521193041.GA25940@amt.cnet> (raw)
In-Reply-To: <4FB9F9B6.50101@linux.vnet.ibm.com>

On Mon, May 21, 2012 at 04:15:50PM +0800, Xiao Guangrong wrote:
> 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.

Or ROM. Or read-only mappings of IVSHMEM (which don't exist yet).


  reply	other threads:[~2012-05-21 19:35 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-21  6:45 [PATCH] KVM: fix async page fault working for readonly mapping Xiao Guangrong
2012-05-21  8:08 ` Gleb Natapov
2012-05-21  8:15   ` Xiao Guangrong
2012-05-21 19:30     ` Marcelo Tosatti [this message]
2012-05-22  5:31       ` Gleb Natapov
2012-05-22 14:27         ` Avi Kivity
2012-05-23  3:09           ` Xiao Guangrong

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