[Bug 224003] xen kernel panics

[Roger Pau Monné]

On Fri, Mar 30, 2018 at 05:43:21PM +0000, Chris wrote:
> On 03/30/18 12:07, Roger Pau Monné wrote:
> > On Thu, Mar 29, 2018 at 11:32:19PM +0000, Chris wrote:
> > > I'm having similar problems with xen on 11.1, AMD64, June 2017.
> > > The OS runs fine, but installed xen from package, setup exactly
> > > as per the handbook and get a kernel panic on two machines,
> > > complaining about iommu not being enabled.
> > 
> > FreeBSD/Xen Dom0 requires a working IOMMU, that's documented in the
> > handbook [0] section 21.8.1.
> > 
> > Can you paste the full output that you get when booting under Xen?
> > 
> > > Machines are: a Sun X4170 to start, then  a Proliant DL380 G7
> > > with E5630 cpu. Both have all the virtualisation options
> > > enabled in the bios, but there are no options on either machine
> > >   for iommu.
> > 
> > On Intel hardware the IOMMU is called VT-d. I have no idea if the
> > hardware that you list has an IOMMU, it depends on both the CPU and
> > the motherboard.
> > 
> > Without VT-d (an IOMMU) FreeBSD/Xen Dom0 won't work.
> > 
> > Roger.
> > 
> > [0] https://www.freebsd.org/doc/handbook/virtualization-host-xen.html
> > .
> > 
> 
> Roger,
> 
> Thanks for the reply and clarification on the meaning of iommu. A bit
> more info on the machine:
> 
> Cpu is actually an E5645, hex core, 2.4GHz
> 32 Gb ram, full ecc
> bios is dated 2011, with:
> 
> VT-d, enabled
> Intel virtualisation tech, enabled
> 
> It's difficult to log info on this, as there is just the "needs iommu"
> message on boot, then halt. Live cd and file edits brought the base
> system back, but nothing in /var/log/xen at all.

You can also boot into FreeBSD (without Xen) by dropping into the
loader prompt and typing:

> unload
> unset xen_kernel

I'm afraid you will need to connect to the server using a serial
console and get the output from there. Without the full serial output
it's hard to figure out what's going on.

Thanks, Roger.