Re: [kvm-ppc-devel] [PATCH] RFC: UseCONFIG_HAS_IOPORTaround vcpu->pio_data

[Hollis Blanchard <hollisb-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>]

On Tue, 2007-12-04 at 13:04 +0800, Zhang, Xiantao wrote:
> 
> Hollis Blanchard wrote:
> > On Tue, 2007-12-04 at 12:39 +0800, Zhang, Xiantao wrote:
> >> Hollis Blanchard wrote:
> >>> Actually, (now that I try to build with it :) this doesn't work
> for
> >>> PowerPC, which defines (or rather, doesn't not define)
> >>> CONFIG_HAS_IOPORT.
> >> 
> >> You mean ppc has ioport , but you don't use current kvm io
> >> infrastructure to handle it ?
> > 
> > It's a matter of perspective. :)
> > 
> > The PowerPC architecture has no "IO" instructions; therefore all IO
> > accesses are MMIO.
> > However, you can place devices with IO ports in a PowerPC system. In
> > this case, the bridges are configured to translate MMIO accesses
> > coming from the processor into IO port accesses on the bus. It is
> > quite common to find standard x86 ISA devices, such as a SuperIO
> 
> Thank you for your elaboration. 
> So, bridge emulation in qemu will take over the responsibility of the
> translation for ppc? 

Yup.

-- 
Hollis Blanchard
IBM Linux Technology Center


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