On Mon, Jun 17, 2024 at 9:28 AM <g.vasilopoulos@uoc.gr> wrote:

Hi again
This does not mean that the cpu is not supported, it just means that instructions/feutures that are above intel icelake will not be available to virtual machines. The cpu should be recognized and work fine at the hypervisor. I think the only extra instruction set that will not be available to virtual machines is intel AMX.
(became available after intel icelake)

When speaking about AMX, you have to consider three layers: kernel, QEMU, libvirt

. support in the KVM kernel module is there since 5.17

If you decline to Red Hat base OS distros, you can refer to this:

https://access.redhat.com/solutions/7033476

that means AMX support is present since 9.0 GA and since 8.6 GA

. support of cpu model SapphireRapids, the first offering AMX as an ISA extension, is in QEMU since 7.0

. support for the SapphireRapids CPU model was added in libvirt 9.4.0

I would say that in CentOS 9 Stream all the dependencies above should be satisfied.

On RH EL 8 based systems, and so also on OLVM, the missing part is related to libvirt still being at 9.0.0-5

Also, speaking about oVirt, I don't know how it manages the dropdown menu when you select "CPU Type" in cluster creation and edit phases.

Does it directly use a command, such as "virsh cpu-models x86_64", on the fly or the list of xml files under /usr/share/libvirt/cpu_map/ directory or an oVirt maintained specific file or inside the engine db?

Any clarification on this?

For the ones without any AMX knowledge, a good starting point to understand its AI acceleration capabilities for CPU based workloads, is here:

https://www.intel.com/content/www/us/en/products/docs/accelerator-engines/advanced-matrix-extensions/overview.html

HIH,

Gianluca