[Pkg-xen-devel] Experiment with rebuilt 4.14.2+25-gb6a8c4f72d-2

[Elliott Mitchell]

On Fri, Aug 20, 2021 at 08:50:44PM -0700, Elliott Mitchell wrote:
> I've got a rough border between what I'm up for and not.  I'm not up for
> running full testing if I can avoid, but I'm also not up for security
> holes of doom.
> 
> As a result my approach was to try building the 4.14.2+25-gb6a8c4f72d-2
> for stable.  The only difference this causes that I've found is to
> depend on libc6 2.28-10 instead of 2.31-13.  I'm concerned about scripts,
> but one has to accept those risks.
> 
> So far things to work as expected.

Configuration from 4.11 works with 4.14 fine.


I've been wanting PVH for a while, but hadn't gotten it working from
Debian packages.  Trying to boot a PVH guest using pvGRUB produces an
error similar to what Colin Watson saw in #776450:

xc: error: panic: xc_dom_elfloader.c:64: xc_dom_guest_type: image not capable of booting inside a HVM container: Invalid kernel
libxl: error: libxl_dom.c:578:libxl__build_dom: xc_dom_parse_image failed

This might be an issue of the Debian GRUB 2.02 packages not liking
Xen 4.14, but reading #776450 I'm wondering whether setups like this were
ever working.


Appears power management is a lower priority for Xen development.  Result
is things include various levels of funkiness.  For Xen 4.11 enabling
higher C-states (lower power) on a core required Domain 0 to have a
corresponding vCPU.  You could offline extra vCPUs after boot by using
`xl vcpu-set`, but you ended up with unused vCPUs.

Unfortunately appears the Linux 4.19.194 kernel is unable to enable
higher C-states with Xen 4.14.  Apparently fixes for Xen 4.14 didn't get
backported to 4.19 (this is discouraging).  I'm unsure who to contact
about this issue.


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