The Ubuntu-power-systems project

Grub2 Support for nested KVM on PowerVM (POWER10)

Bug #2073554 reported by bugproxy
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
The Ubuntu-power-systems project
New
High
Ubuntu on IBM Power Systems Bug Triage
grub2 (Ubuntu)
Status tracked in Oracular
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Oracular
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Bug Description

AVNISH CHOUHAN 2024-06-24 05:57:01 CDT

We have added required changes in grub2 to support KVM on Power. The patch is available in upstream grub. This patch adds support for Radix, Xive and Radix_gtse in Options vector5 which is required for KVM LPARs. KVM LPARs ONLY support Radix and not the Hash. Not enabling Radix on any PowerVM KVM LPARs will result in boot failure.

https://lists.gnu.org/archive/html/grub-devel/2024-05/msg00209.html

[reply] [?] Internal OnlyComment 3AVNISH CHOUHAN 2024-07-01 05:19:38 CDT
Hi,

Upstream commit : https://git.savannah.gnu.org/cgit/grub.git/commit/?id=fa36f6376087b81a4de05623a5cd871a8fa30b35

Thank you,
Avnish Chouhan

bugproxy (bugproxy)
tags: added: architecture-ppc64le bugnameltc-207096 severity-high targetmilestone-inin2404
Changed in ubuntu:
assignee: nobody → Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage)
affects: ubuntu → grub (Ubuntu)
Steve Langasek (vorlon)
affects: grub (Ubuntu) → grub2 (Ubuntu)
Frank Heimes (fheimes)
Changed in ubuntu-power-systems:
assignee: nobody → Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage)
Changed in grub2 (Ubuntu):
assignee: Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage) → nobody
Changed in ubuntu-power-systems:
importance: Undecided → High
Revision history for this message
Mate Kukri (mkukri) wrote :

Hi,

It seems fairly straightforward to cherry-pick this, but it would be nice to know what systems need this.

The current GRUB does work on "KVM on Power", but I suppose newer systems need this? I just wonder what criteria is the cut-off?

Revision history for this message
Frank Heimes (fheimes) wrote (last edit ):

Hi Mate, this is for Power10 systems.
For P10 systems, IBM's commercial hypervisor PowerVM was mandatory.
Just recently nested KVM on P10 was introduced (so KVM on top of PowerVM).
And this patch adds Radix support (and more) - without Radix any PowerVM KVM LPARs will fail to boot with grub.
(That's my understanding, also from the referenced mail thread.)

Revision history for this message
bugproxy (bugproxy) wrote : Comment bridged from LTC Bugzilla

And this patch adds Radix support (and more) - without Radix any PowerVM KVM LPARs will fail to boot.

Mate Kukri (mkukri)
summary: - Grub2 Support for KVM on PowerVM
+ Grub2 Support for nested KVM on PowerVM (POWER10)
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