Re: [Qemu-devel] [Patch] Ali Chipset support for PC [+ questions about alpha-softmmu target]

[Blue Swirl]

On 9/9/08, Brian Wheeler <address@hidden> wrote:
> Hello!
>
>  Long time listener, first time caller...
>
>  Since the ES40 Alpha Emulation project seems to have stalled, I've been
>  looking at what it would take to get QEmu to a state where it could
>  emulate an alpha machine.
>
>  The es40 is basically a PC with an alpha chip instead of an x86 and it
>  uses the Ali1543C south bridge.   This basically is a copy of piix_pci.c
>  so the chipset reports the ALI vendor and device codes to qemu when the
>  "alipc" machine type is selected.

IMHO pc.c would support more machines more cleanly if hardware
definition structures like Sparc ones were used.  Otherwise the patch
looks fine to me.

>  I've booted Knoppix and it seems to work ok...which is no surpise
>  considering how minor the changes are.
>
>  So, now to the questions:
>  * Is anyone else working on a softmmu target for the alpha?
>
>  * What state is the alpha cpu emulation in, and what's the best way to
>  test it?
>
>  * What's the most simple -softmmu target that could be used as a
>  starting point?

Depends on what you know, x86 is quite baroque but everyone knows the
basic architecture. Sparc32 is pretty simple.

>  * Where is the virtual->physical address translation code?  I peeked
>  around and couldn't find it very easily.

cpu_*_handle_mmu_fault(), usually in target-*/helper.c.

>  * Looking over some of the softmmu targets, it looks like the bulk of
>  target work (after the cpu emulation, of course) is just attaching all
>  of the devices in the right places.

True. Also it's not hard to create new devices.