Re: [Xen-devel] Live migration with MMIO pages

To:	Kieran Mansley <kmansley@xxxxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject:	Re: [Xen-devel] Live migration with MMIO pages
From:	Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date:	Wed, 31 Oct 2007 13:32:20 +0000
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On 31/10/07 12:19, "Kieran Mansley" <kmansley@xxxxxxxxxxxxxx> wrote:

> However there's no equivalent test for a non-HVM domain.  I think adding
> such a test to just ignore any MMIO pages would help.  The MMIO pages
> will be unmapped when the live migration finally suspends the domain
> (and so the migration should be possible), but accessing them in the
> mean time is probably not a good idea.  Non-live migration is fine
> because the domain (and so all its devices) are suspended in advance,
> and the MMIO pages are unmapped.

Is mapping the page as cacheable and then reading from it not supported by
the hardware device? E.g., does it need to be uncacheable, or do reads have
side effects?

 -- Keir



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