This proposal moves all the related IRQ routines of the sPAPR machine
behind a sPAPR IRQ backend interface 'spapr_irq' to prepare for future
changes. First of which will be to increase the size of the IRQ number
space, then, will follow a new backend for the POWER9 XIVE IRQ controller.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This proposal introduces a new IRQ number space layout using static
numbers for all devices, depending on a device index, and a bitmap
allocator for the MSI IRQ numbers which are negotiated by the guest at
runtime.
As the VIO device model does not have a device index but a "reg"
property, we introduce a formula to compute an IRQ number from a "reg"
value. It should minimize most of the collisions.
The previous layout is kept in pre-3.1 machines raising the
'legacy_irq_allocation' machine class flag.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
