From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate001.proxmox.com (gate001.proxmox.com [IPv6:2a0f:8001:1:32::40]) by lore.proxmox.com (Postfix) with ESMTPS id EAE921FF0B4 for ; Tue, 10 Nov 2026 15:21:46 +0100 (CET) Received: from gate001.proxmox.com (localhost.localdomain [127.0.0.1]) by gate001.proxmox.com (Proxmox) with ESMTP id B6F9921632; Tue, 10 Nov 2026 15:21:43 +0100 (CET) Message-ID: <3a03cfcb-8bd1-49f9-a066-ec698edcd71a@proxmox.com> Date: Tue, 10 Nov 2026 15:21:39 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH docs] qm: document potential host cpu type drawback To: pve-devel@lists.proxmox.com References: <20260715130131.397579-1-m.sandoval@proxmox.com> Content-Language: en-US From: Jonas Theisen In-Reply-To: <20260715130131.397579-1-m.sandoval@proxmox.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1794320499275 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.095 Adjusted score from AWL reputation of From: address DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment (newer systems) RCVD_IN_DNSWL_MED -2.3 Sender listed at https://www.dnswl.org/, medium trust SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Message-ID-Hash: JA3GARSUYTKJVML7FAO4OT6L4FWXDS7C X-Message-ID-Hash: JA3GARSUYTKJVML7FAO4OT6L4FWXDS7C X-MailFrom: j.theisen@proxmox.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; emergency; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.10 Precedence: list List-Id: Proxmox VE development discussion List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On 7/15/26 15:01, Maximiliano Sandoval wrote: > Signed-off-by: Maximiliano Sandoval > --- > > Notes: > This happened for example on Kernel 7.0.0 where the vmx-mbec is now enabled. > > qm.adoc | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/qm.adoc b/qm.adoc > index 96ba68b..bca5792 100644 > --- a/qm.adoc > +++ b/qm.adoc > @@ -482,6 +482,10 @@ cluster, choose the lowest compatible virtual QEMU CPU type. > > NOTE: Live migrations between Intel and AMD host CPUs have no guarantee to work. > > +WARNING: The 'host' CPU type can potentially enable new CPU features for the > +guest when the guest is restarted after a system upgrade. This can result in > +unexpected consequences. > + > See also > xref:chapter_qm_vcpu_list[List of AMD and Intel CPU Types as Defined in QEMU]. > Gentle ping. I personally would like to see this mentioned in the docs, since this is and will stay a potential problem / hazard to be aware of with this CPU type. So consider this: Reviewed-by: Jonas Theisen