Re: [Qemu-devel] [PATCH 4/4] spapr: Add support for time base offset migration

[Benjamin Herrenschmidt]

On Mon, 2014-04-14 at 21:14 +1000, Benjamin Herrenschmidt wrote:
> On Mon, 2014-04-14 at 17:12 +1000, Alexey Kardashevskiy wrote:
> > Our additional PHBs require @index property which is used to calculate
> > base
> > MMIO and IO ranges. That we could use for LSI/MSI too.
> 
> That works. We need to decide how much interrupt "space" we give to
> each.
> 
> The HW on P8 does 2048 MSIs plus the LSIs but we don't have to copy
> that. The HW does that many because it can be split into 256 PE's but
> our virtual PHBs represent a single PE#.

Note that this value of "256" should itself be an overridable machine
level configuration so we can bump it later if it ever becomes necessary
and still create "backward compatible" VMs.

Cheers,
Ben.