On 12/23/09 20:53, Juraj Hercek wrote:
On 12/23/2009 07:47 PM, Manuel Bouyer wrote: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).
Cool!
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 busIt sound's like a good candidate causing the issue. However, in this case, I don't think it can be fixed (easily, if at all) in NetBSD code. Is there an easy way how to verify that DMA doesn't spoil dom0 memory?
Woa, I am not sure that the dom0 could detect such situation with ease. Maybe see "xm dmesg" (in dom0), were MM errors could be logged.
-- Jean-Yves Migeon jeanyves.migeon%free.fr@localhost