Re: HVM domains crash after upgrade from XEN 4.5.1 to 4.5.2

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

> >>Your analysis was absolutely spot on. After re-thinking this for a
> >>moment, I thought going down that route first would make a lot of sense
> >>as PV guests still do work and one of the differences to HVM domUs is
> >>that the former do _not_ require SeaBIOS. Looking at my log files of
> >>installed packages confirmed an upgrade from SeaBIOS 1.7.5 to 1.8.2 in
> >>the relevant timeframe which obviously had not made it to the hvmloader
> >>of xen-4.5.1 as I did not re-compile xen after the upgrade of SeaBIOS.
> >>
> >>So I re-compiled xen-4.5.1 (obviously now using the installed SeaBIOS
> >>1.8.2) and the same error as with xen-4.5.2 popped up - and that seemed
> >>to strongly indicate that there indeed might be an issue with SeaBIOS as
> >>this probably was the only variable that had changed from the original
> >>install of xen-4.5.1.

I recall seeing this way back in Fedora 20 days. I narrowed it down the 
SeaBIOS version that was a standalone package to not have CONFIG_XEN.

Having that fixed in the SeaBIOS package fixed it.

> >>
> >>My next step was to downgrade SeaBIOS to 1.7.5 and to re-compile
> >>xen-4.5.1. Voila, the system was again up and running. While still
> >>having SeaBIOS 1.7.5 installed, I also re-compiled xen-4.5.2 and ... you
> >>probably guessed it ... the problem was gone: The system boots up with
> >>no issues and everything is fine again.
> >>
> >>So in a nutshell: There seems to be a problem with SeaBIOS 1.8.2
> >>preventing HVM doamins from successfully starting up. I don't know what
> >>this is triggered from, if this is specific to my hardware or whether
> >>something else in my environment is to blame.
> >>
> >>In any case, I am again more than happy to provide data / run a few
> >>tests should you wish to get to the grounds of this.
> >>
> >>I do owe you a beer (or any other drink) should you ever be at my
> >>location (i.e. Vienna, Austria).
> >>
> >>Many thanks again for your analysis and your first class support. Xen
> >>and their people absolutely rock!
> >>
> >>Atom2
> >I'm a little late to the thread but can you send me (you can do it
> >off-list if you'd like) the USE flags you used for xen, xen-tools and
> >seabios? Also emerge --info. You can kill two birds with one stone by
> >using emerge --info xen.
> Hi Doug,
> here you go:
> USE flags:
> app-emulation/xen-4.5.2-r1::gentoo  USE="-custom-cflags -debug -efi -flask
> -xsm"
> app-emulation/xen-tools-4.5.2::gentoo  USE="hvm pam pygrub python qemu
> screen system-seabios -api -custom-cflags -debug -doc -flask (-ocaml) -ovmf
> -static-libs -system-qemu" PYTHON_TARGETS="python2_7"
> sys-firmware/seabios-1.7.5::gentoo  USE="binary"
> emerge --info: Please see the attached file
> >I'm not too familiar with the xen ebuilds but I was pretty sure that
> >xen-tools is what builds hvmloader and it downloads a copy of SeaBIOS
> >and builds it so that it remains consistent. But obviously your
> >experience shows otherwise.
> You are right, it's xen-tools that builds hvmloader. If I remember
> correctly, the "system-seabios" USE flag (for xen-tools) specifies whether
> sys-firmware/seabios is used and the latter downloads SeaBIOS in it's binary
> form provided its "binary" USE flag is set. At least that's my
> understanding.
> >I'm looking at some ideas to improve SeaBIOS packaging on Gentoo and
> >your info would be helpful.
> Great. Whatever makes gentoo and xen stronger will be awesome. What
> immediately springs to mind is to create a separate hvmloader package and
> slot that (that's just an idea and probably not fully thought through, but
> ss far as I understood Andrew, it would then be possible to specify the
> specific firmware version [i.e. hvmloader] to use on xl's command line by
> using firmware_override="full/path/to/firmware").
> 
> I also found out that an upgrade to sys-firmware/seabios obviously does not
> trigger an automatic re-emerge of xen-tools and thus hvmloader. Shouldn't
> this also happen automatically as xen-tools depends on seabios?

No and yes. You can use 'seabios' also with a standalone QEMU (so not
hardware virtualization).