On Tue, 2007-10-16 at 00:03 +0200, Andi Kleen wrote:

quoted

Subject: [PATCH 12/12] xfs: eagerly remove vmap mappings to avoid
upsetting Xen

This should be probably done unconditionally because it's a undefined
dangerous condition everywhere.

Should be done unconditionally.  One could remap the underlying physical
space to include an MMIO region, and speculative reads from the
cacheable virtual mapping of that region could move the robot arm,
destroying the world.

Zach