Re: [Qemu-devel] [PATCH 10/13] Implement early printk in virtio-console

[Anthony Liguori]

Alexander Graf wrote:
> On our S390x Virtio machine we don't have anywhere to display early printks
> on, because we don't know about VGA or serial ports.
>
> So instead we just forward everything to the virtio console that we created
> anyways.
>   

What is this used for?

> Signed-off-by: Alexander Graf <address@hidden>
> ---
>  hw/virtio-console.c |    7 +++++++
>  hw/virtio-console.h |    2 ++
>  2 files changed, 9 insertions(+), 0 deletions(-)
>
> diff --git a/hw/virtio-console.c b/hw/virtio-console.c
> index 57f8f89..cd6cf20 100644
> --- a/hw/virtio-console.c
> +++ b/hw/virtio-console.c
> @@ -105,6 +105,13 @@ static void vcon_event(void *opaque, int event)
>      /* we will ignore any event for the time being */
>  }
>  
> +void virtio_console_print_early(VirtIODevice *vdev, uint8_t *buf)
> +{
> +    VirtIOConsole *s = to_virtio_console(vdev);
> +
> +    qemu_chr_write(s->chr, buf, strlen((char*)buf));
> +}
> +
>  static void virtio_console_save(QEMUFile *f, void *opaque)
>  {
>      VirtIOConsole *s = opaque;
> diff --git a/hw/virtio-console.h b/hw/virtio-console.h
> index 84d0717..f3ccc3c 100644
> --- a/hw/virtio-console.h
> +++ b/hw/virtio-console.h
> @@ -16,4 +16,6 @@
>  /* The ID for virtio console */
>  #define VIRTIO_ID_CONSOLE 3
>  
> +void virtio_console_print_early(VirtIODevice *vdev, uint8_t *buf);
> +
>  #endif
>