Re: cpu vmx migration issue
Hi.
On Mon, May 20, 2024 at 21:04:59 +0800, d tbsky wrote:
Hi:
I update our RHEL9 system to RHEL 9.4, which brings libvirt 10.0.
I try to calculate the cpu baseline for our two-node cluster with
command "virsh domcapabilities" then "virsh hypervisor-cpu-baseline
--migratable". the result has many cpu features begin with "vmx".
the test cluster has cpu "intel E3-1280 V3" and "intel
I3-9100F".
when I try live migrate vm, it failed and told me "guest CPU doesn't
match specification: missing features:
vmx-apicv-register,vmx-apicv-vid,vmx-posted-intr".
Interesting, hypervisor-cpu-baseline is supposed to provide an
intersection of both CPU models. I wonder whether we have a bug
somewhere, could you share the host-model definition from virsh
domcapabilities from both hosts? The easiest way is running
$ virsh domcapabilities | xmllint --xpath
'//cpu/mode[@name="host-model"]' -
at another cluster with cpu " Intel i5-2520M" and
"Intel
i7-9750H" the migration works fine for the calculated cpu result.
although there are still many "vmx" cpu features in the result.
if I delete all these vmx features, then migration works fine for
both cluster, like old days.
I wonder what's the benefit to expose these vmx features to guest
if I don't do any nested virtualization.
Well, they were always exposed by QEMU, libvirt just added support for
them and thus they are visible in the XMLs as well.
is it ok the drop all these vmx cpu features for a guest?
thanks a lot for help!
Sure, unless you specifically need some of them, you can drop them. They
will be added to the XML anyway during VM startup.
Jirka