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Date: Thu, 21 Mar 2013 11:21:50 -0600
From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Message-ID: <20130321172150.GA3118@obsidianresearch.com>
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Subject: Re: [Qemu-devel] [PATCH] rdma: don't make pages writeable if not
	requiested
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Roland Dreier <roland@kernel.org>, qemu-devel@nongnu.org, "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>, Yishai Hadas <yishaih@mellanox.com>, LKML <linux-kernel@vger.kernel.org>, "Michael R. Hines" <mrhines@linux.vnet.ibm.com>, Hal Rosenstock <hal.rosenstock@gmail.com>, Sean Hefty <sean.hefty@intel.com>, Christoph Lameter <cl@linux.com>

On Thu, Mar 21, 2013 at 07:15:25PM +0200, Michael S. Tsirkin wrote:

> No because application does this:
> init page
> 
> ...
> 
> after a lot of time
> 
> ..
> 
> register
> send
> unregister
> 
> so it can not be read only.

mprotect(READONLY)
register
send
unregister
mprotect(WRITABLE)

?

With something like GIFT the app already has to give up writing to the
pages while they are moving, so changing the protection seems in line
with that?

Jason