Re: [Qemu-devel] [RFC] qemu VGA endian swap low level drawing changes

[Peter Maydell]

On 17 June 2014 22:32, Benjamin Herrenschmidt <address@hidden> wrote:
> Additionally, I wouldn't mind of we did a quick "trick" equivalent (but
> cleaner) to what I did in my patch which is when the pseries guest calls
> the hypervisor call to change the interrupt endian mode, we notify VGA
> and switch its endian mode, so we work "by default" with kernels not
> updated to know about that register. But this is open for debate. It's
> somewhat "acceptable" in the context of our hypercall being a
> "paravirtualized" interface, so it can be argued that the hypercall
> poking at the VGA chip is equivalent to some FW doing so :-)

I'm definitely against this. Have your guest change the behaviour
of the VGA device by explicitly prodding the VGA device, not by
back-door side-effects of something else that it happens to do
on one particular guest for one particular architecture, please.

thanks
-- PMM