Hello,
As you're probably aware, it turns out that pretty much every CPU
made in the last 10 years is broken, and while this affects almost
all computers, this is going to have a particularly nasty effect on
virtualisation providers such as BitFolk.
The Xen project last night released the first version of their
advisory which is XSA-254:
https://xenbits.xen.org/xsa/advisory-254.html
This is with no embargo, because the original embargo had to be
abandoned by the discoverers of the bugs.
As you can see, unfortunately the Xen project have no resolutions
for any of this available as yet.
There's three different issues here:
1. SP1/Spectre (CVE-2017-5753)
2. SP2/Spectre (CVE-2017-5715)
3. SP3/Meltdown (CVE-2017-5754)
There isn't any known resolution for (1) yet.
Xen are working on mitigations for (2).
It's possible to avoid (3) by going to HVM mode, but that is a huge
change that brings other problems with it. It can also be avoided by
running in PVH mode, but very few guest kernels will be new enough
to support that. Xen are hoping to come up with a way to run
PV-inside-PVH but they're not ready with that yet.
There will likely be other strategies to fix or mitigate these
issues in the coming days.
So I'm afraid there currently is no concrete plan because there is
very little information available yet. All I can tell you is that
there will be a need for short-notice reboots to apply relevant
fixes. I will post again when there is any useful information.
Cheers,
Andy
--
https://bitfolk.com/ -- No-nonsense VPS hosting
Hi,
I haven't had chance to personally check this out but apparently the
latest CentOS 7 kernel package doesn't boot under Xen PV:
https://bugs.centos.org/view.php?id=13763
This may be highly relevant to you because an update was just pushed
out for the KPTI feature (to help mitigate Spectre/Meltdown etc in
Linux).
As mentioned in that bug report, there are patches to fix this but
they haven't yet been applied to the main CentOS kernel package.
In the mean time you can use the kernel package from the CentOSPlus
repository which does have this fix and the KPTI one.
https://wiki.centos.org/AdditionalResources/Repositories/CentOSPlus
All of this was researched by a customer having the problem today
and it resolved it for them.
Cheers,
Andy
--
https://bitfolk.com/ -- No-nonsense VPS hosting