Re: [Xen-devel] Booting NetBSD in pygrub

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2013-09-09 at 19:52 +0200, M. Boerschig wrote:
> On 09/09/13 14:35, Ian Campbell wrote:
> > On Sat, 2013-09-07 at 11:56 +0000, M. Boerschig wrote:
> > I think this implies a Linux dom0?
> 
> Yes, of course. I didn't even get a recent xen (> 4.2) to compile on my 
> NetBSD machine.
> 
> >
> > I imagine this is equally broken with a Linux domU, because it doesn't
> > seem likely to be guest specific, given that it is mostly before the
> > guest runs...
> >
> 
> An Ubuntu domU works on this same machine, so I think this problem is 
> limited to my use case (or a similar one, like solaris)

In this case do you get the interactive menu? I wonder if passing
bootloader_args = ["--entry=0"] would reproduce the same error you are
seeing by skipping the menu and making it behave like sniff_solaris?

> > This stuff ha been a bit fragile in the past, I wouldn't be too
> > surprised if it had regressed, especially since it isn't especially
> > amenable to automated testing.
> >
> > What is supposed to happen is that pygrub gets launched attached to a
> > pty, and that ptr gets written to xenstore such that the xenconsole
> > client connects to it and presents the pygrub output to the user as if
> > it were the guest console, xl acts as a pump copying data back and forth
> > between the console pty and pygrubs pty (since both console and pygrub
> > expect to be a slave). Much of this code is in libxl_bootloader.c.
> >
> > Once pygrub exits this pty disappears and the console client should
> > reattach to the real guest console pty, which is provided by
> > xenconsoled.
> >
> > It sounds like that first connection is not going to the right place or
> > is otherwise broken.
> >
> > Are you seeing the pygrub menu? DO you expect to? Perhaps the automatic
> > exit of the first session is not working?
> 
> No, and I didn't expect a menu to appear.
> I assumed a menu is only displayed if the run_grub()-method succeeds in 
> finding a valid GRUB menu.lst/config on the disk.
> I used the sniff_solaris() code as a guideline: if I understand the code 
> correctly it just returns a configuration dictionary without displaying 
> anything.

OK.

> > The last relevant looking commit to libxl_bootloader.c was
> > 7253e0fd1aeb3ae7d4714bcc1d86b846b3331995 which looks like the sort of
> > thing which might accidentally introduce such behaviour.
> 
> Thanks for the pointer, I'll investigate if pygrub's exit is properly 
> handled later this week.

Great, please let us know how you get on!

Ian.



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