[PATCH v5 0/9] Guest XenStore page allocation for 11 Dom0less domUs

[Stefano Stabellini <stefano.stabellini@xxxxxxx>]

Hi all,

The last version (v4) of this patch series [1] was fully acked and
committed. However, we later discovered that it caused regressions with
older Linux kernels without a fix [2], so we reverted the patch series
from Xen.

In the meantime, Linux backported the fix [2] to all kernels, so at
present there are no regressions any longer.

This update on the patch series contains the original v4 patches
unmodified. It also updates our automation testing infrastructure to use
a newer kernel. It adds a test to validate the feature introduced by
this patch series (PV drivers together with 11 mapped guests).

Finally, this patch series introduces a new dom0less option to retain
the old behavior in case users want to run older unpatched Linux kernel
versions.

To verify that the legacy option works and retains compatibility with
older unpatched kernels, I added a test at the end of the series using
the older unpatched Linux kernel and the newly introduced "legacy"
dom0less option. I don't suggest we commit this last test but if you
think otherwise, please let me know and I can clean it up and also add
the ImageBuilder part of it (a way to set the legacy option in the
ImageBuilder config file).

Cheers,

Stefano


[1] https://marc.info/?l=xen-devel&m=171659112108921
[2] a3607581cd49 "drivers/xen: Improve the late XenStore init protocol"
[3] https://gitlab.com/xen-project/people/sstabellini/xen/-/pipelines/1656094397