Re: [RFC PATCH 0/4] hw/intc: enable GICv4 memory layout for GICv3 driver

[Leif Lindholm]

On Tue, Feb 02, 2021 at 10:39:22 +0000, Peter Maydell wrote:
> On Sun, 24 Jan 2021 at 02:53, Leif Lindholm <leif@nuviainc.com> wrote:
> >
> > GICv4 sets aside 256K per redistributor configuration block, whereas GICv3
> > only uses 128K. However, some codebases (like TF-A, EDK2) will happily use
> > the GICv3 functionality only.
> >
> > This set aims at enabling these codebases to run, without actually enabling
> > full support for GICv4.
> >
> > This creates a ... problematic ... system, which will misbehave if you try
> > to use the virtual LPIs. But it does help with letting me use QEMU for
> > modelling a platform containing a GICv4, and share firmware images with
> > other prototyping platforms.
> 
> So, what's your aim for this series? I think we could reasonably
> take patches 2 and 4 upstream (they are changes we'll want for eventual
> v4 emulation support), but I don't really want 1 and 3.
> That would reduce the delta you're carrying locally, at least.

That would be much appreciated.

In a way, I wanted to test the waters a bit with regards to whether
gicv4 emulation could be introduced gradually, and whether doing so by
extending the existing gicv3 driver was the way to go.

Anyway, for now, I'll address your comments and send out a 2-part v2,
containing 2,4/4.

Best Regards,

Leif

> I suppose we should look at what changes QEMU needs for KVM in-kernel GICv4
> support at some point...
> 
> thanks
> -- PMM