On 30.10.2012, at 16:35, Cornelia Huck <cornelia.huck@xxxxxxxxxx> wrote: > On Tue, 30 Oct 2012 16:12:47 +0100 > Alexander Graf <agraf@xxxxxxx> wrote: > >> >> >> On 30.10.2012, at 15:29, Cornelia Huck <cornelia.huck@xxxxxxxxxx> wrote: >> >>> On Tue, 30 Oct 2012 14:43:10 +0100 >>> Alexander Graf <agraf@xxxxxxx> wrote: >>> >>>> On 10/30/2012 01:59 PM, Cornelia Huck wrote: >>>>> On Mon, 29 Oct 2012 19:14:19 +0100 >>>>> Alexander Graf<agraf@xxxxxxx> wrote: >>>>> >>>>>> On 29.10.2012, at 14:07, Cornelia Huck wrote: >>>>>> >>>>>>> This code is transport agnostic and can be used by both the legacy >>>>>>> virtio code and virtio_ccw. >>>>>> Would it be possible to actually send real virtio or sclp console commands for early printk? That'd make things a lot easier on the user space end. Combining two completely separate character channels (early printk + sclp or early printk + virtio-console) is really tricky. >>>>>> >>>>> This code is only used if we use a virtio console device. The sclp >>>>> code path is completely different. >>>> >>>> Ah, so the sclp early console works differently? >>> >>> sclp consoles are registered via console_initcall(). I'm not aware of >>> 'early' handling there (although I don't really know the code well.) >>> >>>> >>>>> What do you mean with "real virtio console commands"? The message is >>>>> just put on the output queue anyway. >>>> >>>> For virtio-console, yes. For the early printk it is sent to the >>>> hypervisor using a hypercall, not through the virtio queue. So it >>>> arrives at a completely different end point that usually has no >>>> knowledge of the virtio-console output driver. >>> >>> virtio setup is a core_initcall, which is done way later than the >>> console_initcalls (including s390_virtio_console_init). According to >>> the comments, virtio_cons_early_init is there exactly for that reason. >> >> It's never worked on upstream QEMU. > > It did on kuli ;) Kuli had no concept of multiple char outputs ;) > >> Can we just drop kvm specific early printk support then? > > I'd prefer to leave this cleanup in the series for now. Whether we want > to do something in qemu or remove this is something we can discuss > later. In the meantime, there's sclp :) Sure. In fact, it basically drops early printk for sclp console type machines. So I'm all happy. Alex-- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
