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From: Keir Fraser <keir.xen@gmail.com>
To: Olaf Hering <olaf@aepfle.de>,
	Andres Lagar-Cavilla <andres@lagarcavilla.org>
Cc: andres@gridcentric.ca, xen-devel@lists.xensource.com,
	Tim Deegan <tim@xen.org>,
	ian.campbell@citrix.com, adin@gridcentric.ca
Subject: Re: [PATCH 0 of 3] Update paging/sharing/access interfaces v2
Date: Fri, 10 Feb 2012 12:04:23 -0800	[thread overview]
Message-ID: <CB5AB847.2AF41%keir.xen@gmail.com> (raw)
In-Reply-To: <20120210194517.GA23684@aepfle.de>

On 10/02/2012 11:45, "Olaf Hering" <olaf@aepfle.de> wrote:

>> Actually, this hiatus allows me to float a perhaps cleaner way to map the
>> ring: the known problem is that the pager may die abruptly, and Xen is
>> still posting events to a page now belonging to some other dom0 process.
>> This is dealt with in the qemu-dm case by stuffing the ring in an unused
>> pfn (presumably somewhere in the mmio hole?)
>> 
>> Would that work? Is there a policy for parceling out these "magic pfn's"?
> 
> I was just thinking about this issue. The bug is that the ring lives in
> dom0, the page should belong to domU and should be destroyed along with
> it. And ring users in dom0 should request (and maybe initially allocate
> and setup) a certain gfn belonging to domU.

Yes indeed. The gpfn could be allocated by the domain builder, or by
hvmloader (which might be too late!).

 -- Keir

  reply	other threads:[~2012-02-10 20:04 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-09  6:08 [PATCH 0 of 3] Update paging/sharing/access interfaces v2 Andres Lagar-Cavilla
2012-02-09  6:08 ` [PATCH 1 of 3] Use memops for mem paging, sharing, and access, instead of domctls Andres Lagar-Cavilla
2012-02-09 17:21   ` Ian Jackson
2012-02-09 20:33     ` Andres Lagar-Cavilla
2012-02-09  6:08 ` [PATCH 2 of 3] x86/mm: New sharing audit memop Andres Lagar-Cavilla
2012-02-09 17:04   ` Ian Jackson
2012-02-09  6:08 ` [PATCH 3 of 3] Tools: Sanitize mem_event/access/paging interfaces Andres Lagar-Cavilla
2012-02-10 16:13 ` [PATCH 0 of 3] Update paging/sharing/access interfaces v2 Tim Deegan
2012-02-10 18:13   ` Andres Lagar-Cavilla
2012-02-10 19:45     ` Olaf Hering
2012-02-10 20:04       ` Keir Fraser [this message]
2012-02-10 20:11         ` Andres Lagar-Cavilla
2012-02-10 20:29           ` Keir Fraser

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