Re: [Qemu-ppc] [Qemu-devel] [PATCH v2 4/6] prep: move int-ack register from PReP to Raven PCI emulation

[Hervé Poussineau]

Andreas Färber a écrit :
> Am 14.04.2012 22:48, schrieb Hervé Poussineau:
> > Register is one byte-wide (as per specification), so there is no need to 
> > specify endianness.
>
> The region was 4 bytes before, now it's 1. What happens when a 4-byte
> read is attempted at that address? Do we need to specify the valid
> widths for the MemoryRegion? Or is such a read constructed from this
> region and (assuming) the return value of an unassigned read?

At first, Linux and IBM 40p firmware only attempt a 1-byte read to this 
address.
In the case a 4-byte read is attempted to address 0xbffffff0, memory 
region layer will still call ppc_intack_read() function with size=4.

However, by changing region size from 4 to 1, you prevent direct reads
of 0xbffffff1..0xbffffff3, which I think is not a big loss (and is 
closer to specification).

> > diff --git a/hw/prep_pci.c b/hw/prep_pci.c
> > index 8b29da9..43847f5 100644
> > --- a/hw/prep_pci.c
> > +++ b/hw/prep_pci.c
> > @@ -25,10 +25,12 @@
> >  #include "hw.h"
> >  #include "pci.h"
> >  #include "pci_host.h"
> > +#include "pc.h"
>
> Is that for pic_read_irq()?

Yes. All i8259-related functions are declared in pc.h

Hervé