Re: [Qemu-devel] [PATCH v2 1/2] memory: Fix old portio word accesses

[Avi Kivity]

On 09/18/2011 07:28 PM, Jan Kiszka wrote:
> >>
> >>  This is PIO, limited by the x86 address space to 16 bit. Will add a
> >>  comment.
> >
> >  x86 PIO is not limited to 16 bits, just ISA, which memory.c knows
> >  nothing about.
>
> Confused address and data, the former is limited 16, the latter can be
> 32 as well. But I guess only ISA models made use of the core's split up
> service, and that's why QEMU limited itself accordingly.

Let's not bury such details in the core.

> >
> >>  >    Why not use access_with_adjusted_size()?
> >>
> >>  Because of different accessor prototypes.
> >>
> >
> >  Can be thunked.  There is a different issue, a_w_a_s() can use small
> >  accesses to emulate large ones, but not vice versa.  It needs fixing
> >  anyway.
> >
>
> IIRC, that's a feature: Devices not implementing small accesses tend to
> refuse them in reality.

I don't think this holds for pci; there the bus always generates 32-bit 
writes with separate byte enables for each lane.  The device need not 
even be aware of a sub-word access, for reads.

--
error compiling committee.c: too many arguments to function