Re: [PATCH v1 1/2] xen/riscv: skip disabled CPU nodes when probing ISA extensions

[Baptiste Le Duc <baptiste.le-duc@xxxxxxxxxx>]

> riscv_fill_hwcap_from_isa_string() intersects the riscv,isa of every CPU
> node under /cpus, including the ones with status = "disabled". Such a
> hart is never used by Xen, yet it can still remove extensions from the
> host ISA: e.g. a disabled hart without the H extension makes Xen panic
> with "Xen requires extension: h", even though every hart Xen runs on
> implements it.
> 
> Skip CPU nodes which aren't available.

has_isa_extensions_property() still walks the disabled nodes, so the two
loops over /cpus now disagree on which harts count. Rather than adding
the check loop by loop, can we filter them in one place, e.g. with a 
dt_for_each_available_child_node() iterator, so no /cpus walk sees a disabled
hart?

-- 
Baptiste Le Duc <baptiste.le-duc@xxxxxxxxxx>