Re: [PATCH kvmtool 2/4] arm/fdt.c: Warn if MMIO device doesn't provide a node generator

[Andre Przywara <andre.przywara@arm.com>]

On Wed,  9 Jun 2021 19:38:10 +0100
Alexandru Elisei <alexandru.elisei@arm.com> wrote:

> Print a more helpful warning when a MMIO device hasn't set a function to
> generate an FDT instead of causing a segmentation fault by dereferencing a
> NULL pointer.

Not calling generate_mmio_fdt_nodes() if it's NULL is certainly a good
idea, but how did you trigger it?
Because I am wondering whether every MMIO device needs to have an DT
generator? And if that's not the case, a warning might be already too
much.

So either just drop a print at all or use pr_info()/pr_debug()?

Cheers,
Andre

> 
> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
> ---
>  arm/fdt.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/arm/fdt.c b/arm/fdt.c
> index 02091e9e0bee..06287a13e395 100644
> --- a/arm/fdt.c
> +++ b/arm/fdt.c
> @@ -171,7 +171,12 @@ static int setup_fdt(struct kvm *kvm)
>  	dev_hdr = device__first_dev(DEVICE_BUS_MMIO);
>  	while (dev_hdr) {
>  		generate_mmio_fdt_nodes = dev_hdr->data;
> -		generate_mmio_fdt_nodes(fdt, dev_hdr, generate_irq_prop);
> +		if (generate_mmio_fdt_nodes) {
> +			generate_mmio_fdt_nodes(fdt, dev_hdr, generate_irq_prop);
> +		} else {
> +			pr_warning("Missing FDT node generator for MMIO device %d",
> +				   dev_hdr->dev_num);
> +		}
>  		dev_hdr = device__next_dev(dev_hdr);
>  	}
>