Re: xbd and large sectors

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

On Fri, Jul 21, 2023 at 04:01:14PM +0200, Christian Kujau wrote:
> On Fri, 21 Jul 2023, Manuel Bouyer wrote:
> > On Fri, Jul 21, 2023 at 11:48:56AM +0200, Manuel Bouyer wrote:
> > > [...]
> > > 
> > > Reading the linux sources, the xbd driver pass "sectors" directly to
> > > set_capacity(), which expects the disk size in 512-byte sectors, so
> > > the backend is doing what linux expects, and NetBSD is miscomputing
> > > the disk size when doing sectors * sector-size.
> > > 
> > > A NetBSD dom0 will never report 4k sectors to the guest so we can just fix
> > > the frontend, and there's no backward compat issue.
> > > 
> > > I will commit a fix to HEAD later today.
> > 
> > Done in xbd_xenbus.c 1.132
> > Christian can you please test and report if it properly fixes the issue ?
> 
> That's...quite awesome, thanks for taking a stab at this so quickly!
> 
> Unfortunately, I don't have much experience with running -current. I have 
> another Netbsd-9.3 VM running on another system, think I can manage and 
> *build* -current there, but I still have to figure out how to create an 
> INSTALL kernel from that (to test PV or PVH), or a bootable ISO to test 
> the HVM case.

In this case you can just use
ftp://asim.lip6.fr/outgoing/bouyer/rel/HEAD/amd64/
or wait for a recent-enough build to show up on
http://nyftp.netbsd.org/pub/NetBSD-daily/HEAD/

Note that you can build NetBSD on any recent unix-ish host (e.g. linux or
macos), you don't need a NetBSD host for that. build.sh will build a
cross-build environnement, even when run on a NetBSD host.

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