From patchwork Tue Apr 5 14:19:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Ene X-Patchwork-Id: 558524 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 5F9B3C433F5 for ; Wed, 6 Apr 2022 01:42:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231758AbiDFBf4 (ORCPT ); Tue, 5 Apr 2022 21:35:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35870 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1447358AbiDEPqU (ORCPT ); Tue, 5 Apr 2022 11:46:20 -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 827DE986D6 for ; Tue, 5 Apr 2022 07:21:16 -0700 (PDT) Received: by mail-wm1-x34a.google.com with SMTP id r6-20020a05600c35c600b0038e6db5da9cso1881715wmq.9 for ; Tue, 05 Apr 2022 07:21:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=Hszu94VumpRyr0badDtcfvajy1SNOqO2jgDbf5Z0Nps=; b=qY0N8pmWaAFou+ddSatPmLwRkgrEK8HfEjjNY9XwuXpbTrYXjHbBKu4R4yRmUmBXRm iEP9ODp0DEXN5VfZiCQOXvgkE2NkUBBQzTaSLWBcc5/u6Jw+JQ3ljnwcet/XJTW2xw2z 2iQnrtyxQaDF08KV8U42xehWTIXuLFn1p3LOroreAxq89OlfsUbRiT8xi/bmBh/b6hkc WjM9buKc1uEAGnlXsbNj8BtvgMWqnfpId0YpPeEGpl+tHSEXXlD7ZdOD78KkKNNbYsD0 5BR5mVpn0Xf3flXizQKT0kycGyAWpumWsd2Mzg0T4UVtHZYzHVP6vP6qFp2QlFQ1pj1B aO4w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=Hszu94VumpRyr0badDtcfvajy1SNOqO2jgDbf5Z0Nps=; b=eaosAYOa76NkGbbZjXjiElDaG4pc8MIUuvY6QPsvZIjC08S1CsuiLWEN3V6mMsGVuv 6IygcBX10EAquSv97tvaPaZCiwi9PtgOq90AIHRUkzJPIA3rbP2fQqE8D+crfaXPyVE2 UhZ9LIVE+cfVwI0zlvVG9CNY7CLwxCwzdohQyDZT1jbhTpnSpdClQFQhLBAiHh+lPiMI Sw0Afdu4ft3p2NORDs4mqrb0nmota7yGjhG4CcRdo8TvrAyEiQqOAgkvMnapQfS5vYOY A+1JIhkc0lA6n324kVYC5uc2BSfSiZ2KDNAXIvmredUg+/fYfhyuGoqoQmpazXK/uUSF QDjw== X-Gm-Message-State: AOAM530xdsADFG30uXHNpqiVFnScBdnZy/OHeEJu+reeMIAx+93HhFd+ KhrKab1qKN1ULRi1kSz3oslRyJoxHDXX7atWJ+c= X-Google-Smtp-Source: ABdhPJwRBdDJvU4AC+1Sku8Povz+T97wxBKdUdU/7yJd6akYPxtZjUzFK5tch5XSP182VdIbxVKZJvPCXzLBBmxmQ7I= X-Received: from sene.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:27c4]) (user=sebastianene job=sendgmr) by 2002:a7b:c5d0:0:b0:355:482a:6f44 with SMTP id n16-20020a7bc5d0000000b00355482a6f44mr3294190wmk.58.1649168474859; Tue, 05 Apr 2022 07:21:14 -0700 (PDT) Date: Tue, 5 Apr 2022 14:19:55 +0000 In-Reply-To: <20220405141954.1489782-1-sebastianene@google.com> Message-Id: <20220405141954.1489782-3-sebastianene@google.com> Mime-Version: 1.0 References: <20220405141954.1489782-1-sebastianene@google.com> X-Mailer: git-send-email 2.35.1.1094.g7c7d902a7c-goog Subject: [PATCH 2/2] watchdog: Add a mechanism to detect stalls on guest vCPUs From: Sebastian Ene To: Wim Van Sebroeck , Guenter Roeck , Rob Herring Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-watchdog@vger.kernel.org, will@kernel.org, qperret@google.com, maz@kernel.org, Sebastian Ene Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org This patch adds support for a virtual watchdog which relies on the per-cpu hrtimers to pet at regular intervals. Signed-off-by: Sebastian Ene --- drivers/watchdog/Kconfig | 8 ++ drivers/watchdog/Makefile | 1 + drivers/watchdog/vm-wdt.c | 215 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 224 insertions(+) create mode 100644 drivers/watchdog/vm-wdt.c diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 01ce3f41cc21..3304d128484e 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -351,6 +351,14 @@ config SL28CPLD_WATCHDOG To compile this driver as a module, choose M here: the module will be called sl28cpld_wdt. +config VM_WATCHDOG + tristate "Virtual Machine Watchdog" + select LOCKUP_DETECTOR + help + Detect CPU locks on the virtual machine. + To compile this driver as a module, choose M here: the + module will be called vm-wdt. + # ALPHA Architecture # ARM Architecture diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index 071a2e50be98..73206cbc3835 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -227,3 +227,4 @@ obj-$(CONFIG_MENZ069_WATCHDOG) += menz69_wdt.o obj-$(CONFIG_RAVE_SP_WATCHDOG) += rave-sp-wdt.o obj-$(CONFIG_STPMIC1_WATCHDOG) += stpmic1_wdt.o obj-$(CONFIG_SL28CPLD_WATCHDOG) += sl28cpld_wdt.o +obj-$(CONFIG_VM_WATCHDOG) += vm-wdt.o diff --git a/drivers/watchdog/vm-wdt.c b/drivers/watchdog/vm-wdt.c new file mode 100644 index 000000000000..ea4351754645 --- /dev/null +++ b/drivers/watchdog/vm-wdt.c @@ -0,0 +1,215 @@ +// SPDX-License-Identifier: GPL-2.0+ +// +// Virtual watchdog driver. +// Copyright (C) Google, 2022 + +#define pr_fmt(fmt) "vm-watchdog: " fmt + +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define DRV_NAME "vm_wdt" +#define DRV_VERSION "1.0" + +#define VMWDT_REG_STATUS (0x00) +#define VMWDT_REG_LOAD_CNT (0x04) +#define VMWDT_REG_CURRENT_CNT (0x08) +#define VMWDT_REG_CLOCK_FREQ_HZ (0x0C) +#define VMWDT_REG_LEN (0x10) + +#define VMWDT_DEFAULT_CLOCK_HZ (10) +#define VMWDT_DEFAULT_TIMEOT_SEC (8) + +struct vm_wdt_s { + void __iomem *membase; + u32 clock_freq; + u32 expiration_sec; + u32 ping_timeout_ms; + struct hrtimer per_cpu_hrtimer; + struct platform_device *dev; +}; + +#define vmwdt_reg_write(wdt, reg, value) \ + iowrite32((value), (wdt)->membase + (reg)) +#define vmwdt_reg_read(wdt, reg) \ + io32read((wdt)->membase + (reg)) + +static struct platform_device *virt_dev; + +static enum hrtimer_restart vmwdt_timer_fn(struct hrtimer *hrtimer) +{ + struct vm_wdt_s *cpu_wdt; + u32 ticks; + + cpu_wdt = container_of(hrtimer, struct vm_wdt_s, per_cpu_hrtimer); + ticks = cpu_wdt->clock_freq * cpu_wdt->expiration_sec; + vmwdt_reg_write(cpu_wdt, VMWDT_REG_LOAD_CNT, ticks); + hrtimer_forward_now(hrtimer, ms_to_ktime(cpu_wdt->ping_timeout_ms)); + + return HRTIMER_RESTART; +} + +static void vmwdt_start(void *arg) +{ + u32 ticks; + int cpu = smp_processor_id(); + struct vm_wdt_s *cpu_wdt = arg; + struct hrtimer *hrtimer = &cpu_wdt->per_cpu_hrtimer; + + pr_info("cpu %u vmwdt start\n", cpu); + vmwdt_reg_write(cpu_wdt, VMWDT_REG_CLOCK_FREQ_HZ, + cpu_wdt->clock_freq); + + /* Compute the number of ticks required for the watchdog counter + * register based on the internal clock frequency and the watchdog + * timeout given from the device tree. + */ + ticks = cpu_wdt->clock_freq * cpu_wdt->expiration_sec; + vmwdt_reg_write(cpu_wdt, VMWDT_REG_LOAD_CNT, ticks); + + /* Enable the internal clock and start the watchdog */ + vmwdt_reg_write(cpu_wdt, VMWDT_REG_STATUS, 1); + + hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + hrtimer->function = vmwdt_timer_fn; + hrtimer_start(hrtimer, ms_to_ktime(cpu_wdt->ping_timeout_ms), + HRTIMER_MODE_REL_PINNED); +} + +static void vmwdt_stop(void *arg) +{ + int cpu = smp_processor_id(); + struct vm_wdt_s *cpu_wdt = arg; + struct hrtimer *hrtimer = &cpu_wdt->per_cpu_hrtimer; + + hrtimer_cancel(hrtimer); + + /* Disable the watchdog */ + vmwdt_reg_write(cpu_wdt, VMWDT_REG_STATUS, 0); + pr_info("cpu %d vmwdt stop\n", cpu); +} + +static int start_watchdog_on_cpu(unsigned int cpu) +{ + struct vm_wdt_s *vm_wdt = platform_get_drvdata(virt_dev); + + vmwdt_start(this_cpu_ptr(vm_wdt)); + return 0; +} + +static int stop_watchdog_on_cpu(unsigned int cpu) +{ + struct vm_wdt_s *vm_wdt = platform_get_drvdata(virt_dev); + + vmwdt_stop(this_cpu_ptr(vm_wdt)); + return 0; +} + +static int vmwdt_probe(struct platform_device *dev) +{ + int cpu, ret, err; + void __iomem *membase; + struct resource *r; + struct vm_wdt_s *vm_wdt; + u32 wdt_clock, wdt_timeout_sec = 0; + + r = platform_get_resource(dev, IORESOURCE_MEM, 0); + if (r == NULL) + return -ENOENT; + + vm_wdt = alloc_percpu(typeof(struct vm_wdt_s)); + if (!vm_wdt) + return -ENOMEM; + + membase = ioremap(r->start, resource_size(r)); + if (!membase) { + ret = -ENXIO; + goto err_withmem; + } + + virt_dev = dev; + platform_set_drvdata(dev, vm_wdt); + if (of_property_read_u32(dev->dev.of_node, "clock", &wdt_clock)) + wdt_clock = VMWDT_DEFAULT_CLOCK_HZ; + + if (of_property_read_u32(dev->dev.of_node, "timeout-sec", + &wdt_timeout_sec)) + wdt_timeout_sec = VMWDT_DEFAULT_TIMEOT_SEC; + + for_each_cpu_and(cpu, cpu_online_mask, &watchdog_cpumask) { + struct vm_wdt_s *cpu_wdt = per_cpu_ptr(vm_wdt, cpu); + + cpu_wdt->membase = membase + cpu * VMWDT_REG_LEN; + cpu_wdt->clock_freq = wdt_clock; + cpu_wdt->expiration_sec = wdt_timeout_sec; + cpu_wdt->ping_timeout_ms = wdt_timeout_sec * MSEC_PER_SEC / 2; + smp_call_function_single(cpu, vmwdt_start, cpu_wdt, true); + } + + err = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, + "virt/watchdog:online", + start_watchdog_on_cpu, + stop_watchdog_on_cpu); + if (err < 0) { + pr_warn("could not be initialized"); + ret = err; + goto err_withmem; + } + + return 0; + +err_withmem: + free_percpu(vm_wdt); + return ret; +} + +static int vmwdt_remove(struct platform_device *dev) +{ + int cpu; + struct vm_wdt_s *vm_wdt = platform_get_drvdata(dev); + + for_each_cpu_and(cpu, cpu_online_mask, &watchdog_cpumask) { + struct vm_wdt_s *cpu_wdt = per_cpu_ptr(vm_wdt, cpu); + + smp_call_function_single(cpu, vmwdt_stop, cpu_wdt, true); + } + + free_percpu(vm_wdt); + return 0; +} + +static const struct of_device_id vmwdt_of_match[] = { + { .compatible = "qemu,vm-watchdog", }, + {} +}; + +MODULE_DEVICE_TABLE(of, vm_watchdog_of_match); + +static struct platform_driver vmwdt_driver = { + .probe = vmwdt_probe, + .remove = vmwdt_remove, + .driver = { + .name = DRV_NAME, + .of_match_table = vmwdt_of_match, + }, +}; + +module_platform_driver(vmwdt_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Sebastian Ene "); +MODULE_DESCRIPTION("Virtual watchdog driver"); +MODULE_VERSION(DRV_VERSION);