Saturday, April 21, 2012
How to enable/disable Intel VT-d on XEN
Usually, you just need 'iommu=1' to enable VT-d. At the same time, most of VT-d features (DMA remapping, snoop control, queued invalidation and interrupt remapping) are enabled by default if they are available. You can use 'no-xxx' to disable a feature, for example, 'iommu=no-snoop' disable snoop control.
When RMRR address range is not in reserved memory (BIOS issue), can use 'iommu_inclusive_mapping=1' to work around it.
The grub configuration is like:
title Xen-Linux (2.6.18-xen)
kernel /boot/xen.gz iommu=1
module /boot/vmlinuz-126.96.36.199-xen root=LABEL=/