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 2F0961FF0E1 for ; Mon, 13 Jul 2026 14:41:09 +0200 (CEST) Received: from gate001.proxmox.com (localhost.localdomain [127.0.0.1]) by gate001.proxmox.com (Proxmox) with ESMTP id E1CEC214C5; Mon, 13 Jul 2026 14:41:02 +0200 (CEST) From: Fiona Ebner To: pve-devel@lists.proxmox.com Subject: [PATCH-SERIES qemu-server v2 0/3] cpu config: disable APICv for Windows 11/2022/2025 to mitigate issues with VBS Date: Mon, 13 Jul 2026 14:40:14 +0200 Message-ID: <20260713124025.121154-1-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: 1783946413309 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.371 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_LOW -0.7 Sender listed at https://www.dnswl.org/, low 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: TTT7B6EM2Y4X4QI6T7TL56YYCWK3GDCE X-Message-ID-Hash: TTT7B6EM2Y4X4QI6T7TL56YYCWK3GDCE 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: Changes in v2: * Disable MBEC by default for machine versions < 11.0 for backwards compat with older kernel and QEMU. 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 qemu-server: Fiona Ebner (3): cpu config: disable vmx-mbec flag for machine versions < 11.0 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 | 46 +++++++++++++++---- src/PVE/QemuServer/Machine.pm | 3 +- src/test/cfg2cmd/cpu-level.conf.cmd | 2 +- src/test/cfg2cmd/win11-host-11.0+pve2.conf | 4 ++ .../cfg2cmd/win11-host-11.0+pve2.conf.cmd | 26 +++++++++++ 6 files changed, 70 insertions(+), 13 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: 6 files changed, 70 insertions(+), 13 deletions(-) -- Generated by git-murpp 0.5.0