Re: [Qemu-devel] [PATCH v3 11/14] ioport: Switch dispatching to memory core layer

["Hervé Poussineau" <hpoussin@reactos.org>]

Jan Kiszka a écrit :
> From: Jan Kiszka <jan.kiszka@siemens.com>
> 
> The current ioport dispatcher is a complex beast, mostly due to the
> need to deal with old portio interface users. But we can overcome it
> without converting all portio users by embedding the required base
> address of a MemoryRegionPortio access into that data structure. That
> removes the need to have the additional MemoryRegionIORange structure
> in the loop on every access.
> 
> To handle old portio memory ops, we simply install dispatching handlers
> for portio memory regions when registering them with the memory core.
> This removes the need for the old_portio field.
> 
> We can drop the additional aliasing of ioport regions and also the
> special address space listener. cpu_in and cpu_out now simply call
> address_space_read/write. And we can concentrate portio handling in a
> single source file.
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---

...

> +
> +static void portio_write(void *opaque, hwaddr addr, uint64_t data,
> +                         unsigned size)
> +{
> +    MemoryRegionPortioList *mrpio = opaque;
> +    const MemoryRegionPortio *mrp = find_portio(mrpio, addr, size, true);
> +
> +    if (mrp) {
> +        mrp->write(mrpio->portio_opaque, mrp->base + addr, data);
> +    } else if (size == 2) {
> +        mrp = find_portio(mrpio, addr, 1, true);
> +        assert(mrp);
> +        mrp->write(mrpio->portio_opaque, mrp->base + addr, data & 0xff);
> +        mrp->write(mrpio->portio_opaque, mrp->base + addr + 1, data >> 8);
> +    }
> +}
> +
> +static const MemoryRegionOps portio_ops = {
> +    .read = portio_read,
> +    .write = portio_write,
> +    .valid.unaligned = true,
> +    .impl.unaligned = true,
> +};
> +

You need to mark these operations as DEVICE_LITTLE_ENDIAN.
In portio_write above, you clearly assume that data is in LE format.

This fixes PPC PReP emulation, which would otherwise be broken with this 
patchset.

Hervé