Re: PCI: disable I/O or mem before probing BAR size

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Mon, May 04, 2020 at 09:17:28PM +0200, Manuel Bouyer wrote:
> Hello,
> while trying to boot a Xen PVH kernel as dom0, I found that Xen doesn't
> allow changing memory-mapped PCI BARs if memory decode is enabled in the
> command register. FreeBSD disables I/O or memory decoding in the command
> register before wiriing 0xffffffff for probing the BAR size/type, and
> re-enables it after. The attached patch (forget the printf, they're for
> debugging a issue with Xen only) does something similar for NetBSD.
> With this (and a few others hacks) I can boot a GENERIC kernel as
> PVH dom0. It also still boots fine on my core i5 laptop.
> 
> Does anyone see a problem with this ?

FYI I commited this, with an updated comment as suggested by Mouse
thanks for the replies

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--