Re: NetBSD 5.99.22 Dom0 + xentools33 + pci export + linux domu

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Tue, Dec 22, 2009 at 08:27:19PM +0100, Jean-Yves Migeon wrote:
> Never looked in details for PCI passthru, but is it really safe to 
> shutdown the "PCI privileged" domain once the associated device has been 
> set up? I am not so sure that domU will play nice during shutdown.

I've done so several time with a xen 3.1.4 setup (while doing bnx(4) work)
without much problems. Both dom0 and domU were netbsd-5 (from memory).

It's possible that a domU doesn't shudown properly the DMA engine of the
device, and it keeps overwriting portions of RAM that Xen would
consider "free". It's especially true for devices like USB controllers
which do constant DMA operations, even if there's no activity on the bus.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
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