[Starlingx-discuss] Support IBRS cpu model.
austin.sun at intel.com
Sat Nov 17 02:59:21 UTC 2018
Thanks your review. I have made new patch  based on your suggestion. Could you help review it again ?
From: Chris Friesen [mailto:chris.friesen at windriver.com]
Sent: Friday, November 16, 2018 11:50 PM
To: starlingx-discuss at lists.starlingx.io
Subject: Re: [Starlingx-discuss] Support IBRS cpu model.
There's a problem with this patch. The way the VCpuModelFilter is designed, the basic idea is that a host with a CPU model "later" in the list can support guests with all CPU models "earlier" in the list.
According to  the "spec-ctrl" and "ssbd" CPU features require host CPU microcode (i.e. that the host is detected as the "-IBRS" model) before it can be used for guest CPUs. This means that a "Skylake-Server" host cannot support a "Broadwell-IBRS" guest, which violates the design of the VCpuModelFilter.
I think as part of adding the -IBRS models we'll have to also modify the filter itself.
On 11/13/2018 11:54 PM, Sun, Austin wrote:
> Hi All:
> if install StarlingX in compute-node with cpu type 'Skylake-Server-IBRS' , it cannot use 'passthrough' type with keyword hw:cpu_model in favor to create instance
> It will prompt "No valid host was found. There are not enough hosts available. computer-0: (VCpuModelFilter) Host VCPU model Skylake-Server-IBRS required Passthrough Code 501"
> After investigation , Libvirt 4.7.0 supports *IBRS (for example IvyBridge-IBRS, Skylake-Server-IBRS) CPU model , but nova and meta favor does not support *IBRS CPU model yet.
> I have made patch for nova and glance.
> Nova will support *-IBRS type vcpu when select passthrough
> Glance will add metadata to support *-IBRS in hw:cpu_model
> Please review these PRs.
> Austin Sun.
>  https://github.com/starlingx-staging/stx-nova/pull/15
>  https://github.com/starlingx-staging/stx-glance/pull/4
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