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

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

On Mon, May 04, 2020 at 04:09:41PM -0400, Mouse wrote:
> > 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.
> 
> Is this permitted behaviour for a PCI device according to the PCI
> specs?

No idea. But the FreeBSD comments says that bad thing could happen
when writing arbitrary values with decoding enabled (they don't mention Xen
specifically), and it makes sense to me.

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