From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7BE77C43334 for ; Fri, 1 Jul 2022 14:41:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233677AbiGAOlO (ORCPT ); Fri, 1 Jul 2022 10:41:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231975AbiGAOlA (ORCPT ); Fri, 1 Jul 2022 10:41:00 -0400 Received: from mail-wm1-x34a.google.com (mail-wm1-x34a.google.com [IPv6:2a00:1450:4864:20::34a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 51BE2F595 for ; Fri, 1 Jul 2022 07:40:25 -0700 (PDT) Received: by mail-wm1-x34a.google.com with SMTP id c185-20020a1c35c2000000b0039db3e56c39so3132872wma.5 for ; Fri, 01 Jul 2022 07:40:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:message-id:mime-version:subject:from:to:cc; bh=f72vaIwdDRJKKgyhDAvpG/wPqltF4guZxd93ZnednlM=; b=QLXtZCx/2BbsgwC4Iwx2bMs9DxdMYumaCezysgylc6xoafelXZYU007Fclwu0SIEGI l5+OABExGosSAAecd+z9tOXKqGGP53DrN5coZCueSL/Cu61Bq+OtPFU+IU1s6+Kmqm39 vBvsCh3t8l7b/kbIf4t21twfda35PFO8cM4s1QL0tcAIZHy85B3zeHmUzrSV9615Acxi /4zkV5UA49UCDMYzWcYX1W1IV5BfOr+Zd9vMldAwA4D/p351CL3/FHIJUDStNMIA/5I0 8wpJrKszpXlXdlPBfZhAVjr90d7WuffTnu4Ay1rzfAUP5Y41xMaMxWgQ6CraDN5Pr3uT f5Ug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=f72vaIwdDRJKKgyhDAvpG/wPqltF4guZxd93ZnednlM=; b=W+zZYnRGH6p6N1/dDQiwKKTutAi7WsLWlvG3eJGfyzxBARzXCNqi+WwDNjsBowGXgs jbkGF29obCgzEyibB3ePfRLjEBqAWFSrKuN9GP6ggVPCsBywCF6fhWORD03+MOUQPTxX +w7Q5F+ZriqrpqHTNLSkJbbyu4ZR+QfFakbG0pZDe9n69+jy+7i4H7mPbt5pPTrzsBMC f8GFq42wi9cE0mK8xPGYnaAwKPK9BL5L/r7e5/v838Ys8gygi/Stn3mdZCVl4O5V+LRf k2eHGX0vhToGON4vOLbUnH9uE41KQ/yLPiDreVIrnaCPfMCx19gLdLQ5QYnvtZUriXAP skGQ== X-Gm-Message-State: AJIora/zM8nYTzl+sIv7tdI8E5w2W4EzlJMOnlnZKn+BQ60BTdd0GdqH R5cRiISu5Z6/qVpEwhFBw/B0YP5441A8v839cX0= X-Google-Smtp-Source: AGRyM1v0CB6Lm1qUdcISaT4k+g3l4Ch6gd3BTqkg3Vk6J71cTw8twfp91PHSeg20JGl30t2EQPslUnGSWIcP+40GHtw= X-Received: from sene.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:27c4]) (user=sebastianene job=sendgmr) by 2002:a05:600c:1f19:b0:3a1:8d3b:91ad with SMTP id bd25-20020a05600c1f1900b003a18d3b91admr3953960wmb.111.1656686423837; Fri, 01 Jul 2022 07:40:23 -0700 (PDT) Date: Fri, 1 Jul 2022 14:40:12 +0000 Message-Id: <20220701144013.1085272-1-sebastianene@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.37.0.rc0.161.g10f37bed90-goog Subject: [PATCH v9 0/2] Detect stalls on guest vCPUS From: Sebastian Ene To: Rob Herring , Greg Kroah-Hartman , Arnd Bergmann , Dragan Cvetic Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, maz@kernel.org, will@kernel.org, vdonnefort@google.com, Guenter Roeck , Sebastian Ene Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org This adds a mechanism to detect stalls on the guest vCPUS by creating a per CPU hrtimer which periodically 'pets' the host backend driver. On a conventional watchdog-core driver, the userspace is responsible for delivering the 'pet' events by writing to the particular /dev/watchdogN node. In this case we require a strong thread affinity to be able to account for lost time on a per vCPU basis. This device driver acts as a soft lockup detector by relying on the host backend driver to measure the elapesed time between subsequent 'pet' events. If the elapsed time doesn't match an expected value, the backend driver decides that the guest vCPU is locked and resets the guest. The host backend driver takes into account the time that the guest is not running. The communication with the backend driver is done through MMIO and the register layout of the virtual watchdog is described as part of the backend driver changes. The host backend driver is implemented as part of: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3548817 Changelog v9: - make the driver depend on CONFIG_OF - remove the platform_(set|get)_drvdata calls and keep a per-cpu static variable `vm_stall_detect` as suggested by Guenter on the (v8) series - improve commit description and fix styling Changelog v8: - fix the yamlint dtschema warning caused by the missing 'reg' property Changelog v7: - fix the dtschema warnings for 'timeout-sec' property - rename vcpu_stall_detector.yaml to qemu,vcpu_stall_detector.yaml and place the file under misc - improve the Kconfig description for the driver by making it KVM specific Changelog v6: - fix issues reported by lkp@intel robot: building for ARCH=h8300 incorrect type in assignment (different address spaces) Sebastian Ene (2): dt-bindings: vcpu_stall_detector: Add qemu,vcpu-stall-detector compatible misc: Add a mechanism to detect stalls on guest vCPUs .../misc/qemu,vcpu-stall-detector.yaml | 51 +++++ drivers/misc/Kconfig | 13 ++ drivers/misc/Makefile | 1 + drivers/misc/vcpu_stall_detector.c | 212 ++++++++++++++++++ 4 files changed, 277 insertions(+) create mode 100644 Documentation/devicetree/bindings/misc/qemu,vcpu-stall-detector.yaml create mode 100644 drivers/misc/vcpu_stall_detector.c -- 2.37.0.rc0.161.g10f37bed90-goog