PCI support check in pcibios_init()

[Adrian-Ken Rueegsegger <ken@codelabs.ch>]

Hi,

We are running Linux as a VM on top of the Muen Separation Kernel [1], where
we only allow PCI config space access of pass-through devices via MMCONFIG. In
this use case the PCI support check in pcibios_init() fails as raw_pci_ops is
not set:

int __init pcibios_init(void)
{
    if (!raw_pci_ops) {
        printk(KERN_WARNING "PCI: System does not support PCI\n");
        return 0;
    }
	...
}

As a consequence device resources are not allocated since the following call to
pcibios_resource_survey() is skipped. Extending the check to also consider
raw_pci_ext_ops (see patch) leads to the proper resource allocation in our use
case.

Is the described change the correct solution or is there a particular reason to
only check raw_pci_ops in pcibios_init()?

Regards,
Adrian

[1] - https://muen.codelabs.ch/