Messages in this thread | | | Subject | Re: [PATCH] Xen-SWIOTBL v0.8.3 used for Xen PCI pass through for PV guests. | From | Alex Williamson <> | Date | Tue, 22 Jun 2010 15:23:25 -0600 |
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On Tue, 2010-06-22 at 15:42 -0400, Konrad Rzeszutek Wilk wrote: > These nineteen patches lay the groundwork for Xen Paravirtualized (PV) > domains to access PCI pass-through devices. These patches utilize the > SWIOTLB library modifications (http://lkml.org/lkml/2010/6/4/272). > > The end user of this is the Xen PCI frontend and Xen PCI [1] which > require a DMA API "backend" that understands Xen's MMU. This allows the > PV domains to use PCI devices.
Hi Konrad,
Sorry if I missed it, but I didn't see any mention or apparent requirement of a hardware iommu in xen for this code. Is that true? If so, is there anything to stop a PV guest with ownership of a DMA capable PCI device from reading all sorts of memory that the domain wouldn't otherwise have access to? I was under the impression that the old PCI front/back for PV guests was mainly an interesting hack with limited applications due to security. Thanks,
Alex
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