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Date: Mon, 4 Jan 2016 11:32:00 +0000
From: David Vrabel <david.vrabel@citrix.com>
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To: "Michael S. Tsirkin" <mst@redhat.com>, <linux-kernel@vger.kernel.org>
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Subject: Re: [Xen-devel] [PATCH v2 33/34] xenbus: use virt_xxx barriers
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 <1451572003-2440-34-git-send-email-mst@redhat.com>
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On 31/12/15 19:10, Michael S. Tsirkin wrote:
> drivers/xen/xenbus/xenbus_comms.c uses
> full memory barriers to communicate with the other side.
> 
> For guests compiled with CONFIG_SMP, smp_wmb and smp_mb
> would be sufficient, so mb() and wmb() here are only needed if
> a non-SMP guest runs on an SMP host.
> 
> Switch to virt_xxx barriers which serve this exact purpose.

Acked-by: David Vrabel <david.vrabel@citrix.com>

If you're feeling particularly keen there's a rmb() consume_one_event()
in drivers/xen/events/events_fifo.c that can be converted to virt_rmb()
as well.

David