Messages in this thread | | | Subject | Re: [PATCH v2] intel-iommu: Quiesce devices before disabling IOMMU | From | David Woodhouse <> | Date | Tue, 24 Sep 2013 14:39:33 +0100 |
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On Tue, 2013-09-24 at 15:16 +0200, Joerg Roedel wrote: > > I am not convinced that this is the right approach. If a device wasn't > translated by VT-d in the old kernel doesn't mean it will not be > translated in the new kernel. How about unconditionally resetting all > PCI busses and/or functions here before IOMMU initialization proceeds?
Forget the IOMMU.
If a device is doing DMA in the old kernel, and *continues* doing DMA under the new kernel, surely something ought to shut it down?
It's the generic kexec or machine_shutdown code which should be doing this, not IOMMU code. *Especially* not Intel-specific IOMMU code. It does not live here.
If anything, the IOMMU gives you a way to *survive* this kind of thing and means that you might get away without quiescing devices when otherwise you would have died.
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