Pull intel iommu updates from David Woodhouse:
"This lays a little of the groundwork for upcoming Shared Virtual
Memory support — fixing some bogus #defines for capability bits and
adding the new ones, and starting to use the new wider page tables
where we can, in anticipation of actually filling in the new fields
therein.
It also allows graphics devices to be assigned to VM guests again.
This got broken in 3.17 by disallowing assignment of RMRR-afflicted
devices. Like USB, we do understand why there's an RMRR for graphics
devices — and unlike USB, it's actually sane. So we can make an
exception for graphics devices, just as we do USB controllers.
Finally, tone down the warning about the X2APIC_OPT_OUT bit, due to
persistent requests. X2APIC_OPT_OUT was added to the spec as a nasty
hack to allow broken BIOSes to forbid us from using X2APIC when they
do stupid and invasive things and would break if we did.
Someone noticed that since Windows doesn't have full IOMMU support for
DMA protection, setting the X2APIC_OPT_OUT bit made Windows avoid
initialising the IOMMU on the graphics unit altogether.
This means that it would be available for use in "driver mode", where
the IOMMU registers are made available through a BAR of the graphics
device and the graphics driver can do SVM all for itself.
So they started setting the X2APIC_OPT_OUT bit on *all* platforms with
SVM capabilities. And even the platforms which *might*, if the
planets had been aligned correctly, possibly have had SVM capability
but which in practice actually don't"
* git://git.infradead.org/intel-iommu:
iommu/vt-d: support extended root and context entries
iommu/vt-d: Add new extended capabilities from v2.3 VT-d specification
iommu/vt-d: Allow RMRR on graphics devices too
iommu/vt-d: Print x2apic opt out info instead of printing a warning
iommu/vt-d: kill bogus ecap_niotlb_iunits()
9f86262dcc