I saw in the change log for the kernel-3.1.5-7 that the Intel IOMMU has been disabled by default. Can someone explain this decision or point me to the right discussion on the internet?
--joshua
On Sat, Dec 17, 2011 at 7:54 AM, Joshua C. joshuacov@googlemail.com wrote:
I saw in the change log for the kernel-3.1.5-7 that the Intel IOMMU has been disabled by default. Can someone explain this decision or point me to the right discussion on the internet?
Dave or Matthew can answer more fully than I can, but there is an on-going patch series to reenable Sandybridge GPU power savings and DMAR conflicts with it some how. I don't recall the details, but you can find them in the discussions between Matthew and Keith Packard on LKML.
Defaulting this to on has caused a number of odd issues in the past, and it is mostly used by people using VT-d to assign physical resources directly to virtual guests. Those doing that can still boot with intel_iommu=on.
josh
On Sat, Dec 17, 2011 at 08:23:47 -0500, Josh Boyer jwboyer@gmail.com wrote:
Defaulting this to on has caused a number of odd issues in the past, and it is mostly used by people using VT-d to assign physical resources directly to virtual guests. Those doing that can still boot with intel_iommu=on.
Does this affect the ability of hostile firewire devices to be able to access memory of a running system?
On Sat, 2011-12-17 at 08:08 -0600, Bruno Wolff III wrote:
Does this affect the ability of hostile firewire devices to be able to access memory of a running system?
If you were hoping to use the IOMMU to protect you from hostile firewire devices, then you'll need to turn it on explicitly now. (I don't actually know if the IOMMU support _does_ protect you from that case though.)
- ajax
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