From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate001.proxmox.com (gate001.proxmox.com [45.144.208.40]) by lore.proxmox.com (Postfix) with ESMTPS id 8EB4D1FF0E0 for ; Thu, 09 Jul 2026 15:42:48 +0200 (CEST) Received: from gate001.proxmox.com (localhost.localdomain [127.0.0.1]) by gate001.proxmox.com (Proxmox) with ESMTP id 60335214D0; Thu, 09 Jul 2026 15:42:48 +0200 (CEST) From: Fiona Ebner To: pve-devel@lists.proxmox.com Subject: [PATCH-SERIES qemu-server 0/2] cpu config: disable APICv for Windows 11/2022/2025 to mitigate issues with VBS Date: Thu, 9 Jul 2026 15:41:59 +0200 Message-ID: <20260709134211.199744-1-f.ebner@proxmox.com> X-Mailer: git-send-email 2.47.3 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1783604524469 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.028 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) 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: YGE2LIEZR7JOVPW4KXK6D3XADV5C6FOH X-Message-ID-Hash: YGE2LIEZR7JOVPW4KXK6D3XADV5C6FOH X-MailFrom: f.ebner@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: As reported in the community forum [0] and enterprise support, Windows with MBEC and VBS can have issues on certain Intel CPUs, leading to guest freezes and 100% CPU usage. The detection/enabling of APICv support in Windows was determined to be related. Disabling vmx-apicv-vid and/or vmx-apicv-register mitigates the issue. Disable both flags starting with a bumped 11.0+pve2 machine version for consistency. [0]: https://forum.proxmox.com/threads/184178 What still would be nice to check is if the issue also happens with a non-host model with nested-virt/vmx present. Otherwise we might want to restrict removing the flags to the host model. qemu-server: Fiona Ebner (2): cpu config: use $version_guard rather than passing $machine_version cpu config: disable APICv for Windows 11/2022/2025 to mitigate issues with VBS src/PVE/QemuServer.pm | 2 +- src/PVE/QemuServer/CPUConfig.pm | 33 +++++++++++++------ src/PVE/QemuServer/Machine.pm | 3 +- src/test/cfg2cmd/win11-host-11.0+pve2.conf | 4 +++ .../cfg2cmd/win11-host-11.0+pve2.conf.cmd | 26 +++++++++++++++ 5 files changed, 56 insertions(+), 12 deletions(-) create mode 100644 src/test/cfg2cmd/win11-host-11.0+pve2.conf create mode 100644 src/test/cfg2cmd/win11-host-11.0+pve2.conf.cmd Summary over all repositories: 5 files changed, 56 insertions(+), 12 deletions(-) -- Generated by git-murpp 0.5.0