On 05/29/2014 07:58 AM, Benjamin Herrenschmidt wrote:

On Wed, 2014-05-28 at 22:49 +1000, Gavin Shan wrote:

quoted

I will remove those "address" related macros in next revision because it's
user-level bussiness, not related to host kernel any more.

If the user is QEMU + guest, we need the address to identify the PE though PHB
BUID could be used as same purpose to get PHB, which is one-to-one mapping with
IOMMU group on sPAPR platform. However, once the PE address is built and returned
to guest, guest will use the PE address as input parameter in subsequent RTAS
calls.

If the user is some kind of application who just uses the ioctl() without supporting
RTAS calls. We don't need care about PE address. 

I am a bit reluctant with that PE==PHB equation we seem to be introducing.

This isn't the case in HW.

It is pseries, not real HW. Does phyp allow multiple real host PEs on the
same virtual PHB?

It's possible that this is how we handle VFIO *today*
in qemu but it doesn't have to be does it ?

It also paints us into a corner if we want to start implementing some kind of
emulated EEH for selected emulated devices and/or virtio.

-- 
Alexey