From: "Theo de Raadt" <deraadt@openbsd.org>
Subject: Re: iwx 64-bit dma
To: Vitaliy Makkoveev <mvs@openbsd.org>
Cc: Brad Smith <brad@comstyle.com>, tech@openbsd.org, stsp@openbsd.org
Date: Wed, 29 Jul 2026 19:12:17 -0600

Vitaliy Makkoveev <mvs@openbsd.org> wrote:

> On Wed, Jul 29, 2026 at 06:51:49PM -0600, Theo de Raadt wrote:
> > Vitaliy Makkoveev <mvs@openbsd.org> wrote:
> > 
> > > The IFXF_MBUF_64BIT flag affects only amd64. All other architectures
> > > still uses memory below 4G. See revision 1.61 of
> > > sys/arch/amd64/amd64/autoconf.c line 129.
> > 
> > I don't see how that matters, that's part of the mechanism for
> > providing memory to drivers.
> > 
> > The diff in question which adds BUS_DMA_64BIT is a declaration to
> > the higher-level code that _all_ chipsets supported by this driver can
> > work with 64 bit-addressable memory if the higher levels provide it.
> > 
> > If one chipset can't do it, the experience will be terrible.
> > 
> > 
> > 
> 
> Well, this means the revision 1.198 of sys/dev/pci/if_iwx.c is wrong and
> should be reverted.

No.

It might answer the question I was asking.