Il 10/09/2012 03:43, Rusty Russell ha scritto:

quoted

Now that vfio is upstream and work on qemu integration
is being worked on, we might finally see people using this bit
to allow memory overcommit with device assignment.

That was left-field.... so you're saying some guest might pull a page
from the balloon and DMA to it, and the vfio device needs to know in
advance that it's going to do it?

Not the vfio device, but the page needs to be pinned with mlock so the
effect is the same.

But what will we do if the guest doesn't ack the bit?

Just pin the whole memory.

Paolo

ie. I don't think it can really be optional.