From mboxrd@z Thu Jan  1 00:00:00 1970
From: Olaf Hering <olaf@aepfle.de>
Subject: Re: fixed location of share info page in HVM guests
Date: Mon, 27 Aug 2012 23:32:26 +0200
Message-ID: <20120827213226.GA17915@aepfle.de>
References: <20120827175504.GA13051@aepfle.de>
	<CC6176AA.3CEB4%keir.xen@gmail.com>
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To: Keir Fraser <keir.xen@gmail.com>
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On Mon, Aug 27, Keir Fraser wrote:

> On 27/08/2012 18:55, "Olaf Hering" <olaf@aepfle.de> wrote:
> 
> > 
> > Recently I tried to move the shared_info page in the pvops kernel during
> > shutdown, see "xen PVonHVM: move shared_info to MMIO before kexec"
> > patch. But this change was reverted because it caused reboot failures
> > because the actual moving of the shared page is fragile.
> 
> How was it fragile? Moving it into MMIO should just work?

The moving itself is not the issue, but the possible access to the page
during the move. Its not atomic, nor can it easily be atomic.

Olaf