Re: Ubuntu 16.04 (xenial) partial success with NetBSD and Xen

["Aaron J. Grier" <agrier%poofygoof.com@localhost>]

On Sun, Jan 01, 2017 at 04:34:40PM +0000, David Brownlee wrote:
> On 1 January 2017 at 05:30, Aaron J. Grier <agrier%poofygoof.com@localhost> wrote:
> > PV Linux kernels boot (with pvgrub), but the ramdisk can't find the
> > Xen block root device.  updates to blkfront drivers somewhere
> > between kernel 3.13.0 (ubuntu 14.04) and 4.4.0 (ubuntu 16.04) seem
> > to prevent newer kernels from attaching the Xen block devices.
> 
> Interestingly a 4.6 kernel dropped into a Ubuntu 16.04 image seems to
> run fine under xen 4.5 and 4.6, so later Linux kernels seem to handle
> this case gracefully.

I updated to a Linux 4.6.4 kernel, and it has the same problem with the
root disk not being found when booting as PV with pvgrub2.  I haven't
tried with pygrub yet.

it looks like this may be a pvgrub2 problem -- it appears to be ejecting
the block device after it loads the kernel and ramdisk:

- at pvgrub2 menu:

/local/domain/0/backend/vbd/5/51712/state = "4"
/local/domain/5/device/vbd/51712/state = "3"
/libxl/5/device/vbd/51712/state = "1"

- continue boot, kernel and ramdisk loaded, looking for root device:

/local/domain/0/backend/vbd/5/51712/state = "6"
/local/domain/5/device/vbd/51712/state = "6"
/libxl/5/device/vbd/51712/state = "1"

state 6 is disconnected or ejected, right?

-- 
  Aaron J. Grier | "Not your ordinary poofy goof." | agrier%poofygoof.com@localhost