Re: [RFC PATCH 1/3] add generic hypercall support

Arnd Bergmann
2009-05-06T16:52:35Z

On Wednesday 06 May 2009, Gregory Haskins wrote:

> Ok, so we would
> need to come up with these pio_calls for x86, and no other arch can use
> the infrastructure (but wait, PPC can use PCI too, so how does that
> work? It must be either MMIO emulation or its not supported? That puts
> us back to square one).

PowerPC already has an abstraction for PIO and MMIO because certain
broken hardware chips don't do what they should, see
arch/powerpc/platforms/cell/io-workarounds.c for the only current user.
If you need to, you could do the same on x86 (or generalize the code),
but please don't add another level of indirection on top of this.