On 19 August 2016 at 14:05, Marc Zyngier [off-list ref] wrote:

On 19/08/16 13:53, Peter Maydell wrote:

quoted

Is it worth specifically saying "performance will be worse", or do we
expect this to only happen on systems where the h/w can't permit direct
access (as opposed to those with bad dt info) ?

We cannot distinguish between the two, unfortunately. Even worse, ACPI
only gives us a base address, and not the size of the region. So even if
the HW was perfectly compliant with SBSA, we have to assume the worse case.

Right, but if we expect this is mostly going to be "you just have
to live with it on this hardware" there's less point in printing
an alarming message, whereas if there's a significant subset of
"dt is just wrong" cases then the alarm might help in getting them
fixed, maybe...

thanks
-- PMM