Re: [Qemu-devel] [QEMU PATCH v2 0/2]: KVM: i386: Add support for save and restore nested state

[Jim Mattson]

On Thu, Nov 1, 2018 at 12:07 PM, Dr. David Alan Gilbert
<address@hidden> wrote:

> OK; the tricky thing is when you upgrade one host in a small cluster as
> you start doing an upgrade, and then once it's got it's first VM you
> can't migrate away from it until others are updated; that gets messy.

One must always be able to migrate off of kernel N+1 back to kernel N.
We depend on that whenever we have to rollback a kernel upgrade.