Messages in this thread | | | Date | Thu, 20 Nov 2008 13:25:18 +0900 | Subject | Re: [GIT PULL] AMD IOMMU updates for 2.6.28-rc5 | From | FUJITA Tomonori <> |
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On Wed, 19 Nov 2008 14:57:50 +0200 Muli Ben-Yehuda <muli@il.ibm.com> wrote:
> > device isolation is not free; e.g. use more memory rather than > > sharing a protection domain. I guess that more people prefer sharing > > a protection domain by default. > > I doubt it, why use an isolation-capable IOMMU at all if not for the > increased reliability? The majority of modern devices---those that you > are likely to find on machines with an IOMMU---don't have DMA > limitations.
I guess that there are still some modern SATA HBAs that are not capable of 64bit DMA. You might be right though.
> > It had been the default option for AMD IOMMU until you hit the > > bugs. IIRC, VT-d also shares a protection domain by default. It > > would be nice to avoid surprising users if the two virtualization > > IOMMUs works in the similar way. > > Calgary has a per-bus protection domain, both on x86 and PPC.
I see. Then it might be better to change VT-d to use a separate protection domain by default.
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