Re: [PATCH v2] PCI: host-generic: Avoid reporting incorrect "missing "reg" property" error

[Bjorn Helgaas <helgaas@kernel.org>]

On Tue, Jan 20, 2026 at 01:44:44PM +1300, Jess wrote:
> When the function pci_host_common_ecam_create() calls
> of_address_to_resource() it assumes all errors from that callsite are due
> to a missing "reg" property in the device tree node.
> 
> This can manifest when running the qemu "virt" board, with a 32-bit kernel
> and `highmem=on`.
> 
> After the following calls:
> of_address_to_resource()
>   -> __of_address_to_resource()
>   -> __of_address_resource_bounds()
> 
> this overflow check can fail due to PCI being out of range:
> if (overflows_type(start, r->start))
> 	return -EOVERFLOW;
> 
> This leads to the very confusing error message:
> pci-host-generic 4010000000.pcie: host bridge /pcie@10000000 ranges:
> pci-host-generic 4010000000.pcie:       IO 0x003eff0000..0x003effffff -> 0x0000000000
> pci-host-generic 4010000000.pcie:      MEM 0x0010000000..0x003efeffff -> 0x0010000000
> pci-host-generic 4010000000.pcie:      MEM 0x8000000000..0xffffffffff -> 0x8000000000
> pci-host-generic 4010000000.pcie: missing "reg" property
> pci-host-generic 4010000000.pcie: probe with driver pci-host-generic failed with error -75
> 
> Make the error message more generic.
> 
> Link: https://www.qemu.org/docs/master/system/arm/virt.html
> Signed-off-by: Jess <jess@jessie.cafe>

Applied to pci/controller/generic for v6.20, thanks!

> ---
>  drivers/pci/controller/pci-host-common.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/pci-host-common.c b/drivers/pci/controller/pci-host-common.c
> index c473e7c03bac..d6258c1cffe5 100644
> --- a/drivers/pci/controller/pci-host-common.c
> +++ b/drivers/pci/controller/pci-host-common.c
> @@ -32,7 +32,7 @@ struct pci_config_window *pci_host_common_ecam_create(struct device *dev,
>  
>  	err = of_address_to_resource(dev->of_node, 0, &cfgres);
>  	if (err) {
> -		dev_err(dev, "missing \"reg\" property\n");
> +		dev_err(dev, "missing or malformed \"reg\" property\n");
>  		return ERR_PTR(err);
>  	}
>  
> -- 
> 2.51.2
>