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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 611BBC4332B for ; Tue, 24 Mar 2020 07:57:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3BED22076A for ; Tue, 24 Mar 2020 07:57:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="LeY4fFDf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727642AbgCXH5p (ORCPT ); Tue, 24 Mar 2020 03:57:45 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:37550 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725869AbgCXH5a (ORCPT ); Tue, 24 Mar 2020 03:57:30 -0400 Received: by mail-pg1-f194.google.com with SMTP id a32so8630504pga.4; Tue, 24 Mar 2020 00:57:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=qB8cosFg/V+ZgSCX/jWtnk8u0ihozSaIQH9qUkXCmZ8=; b=LeY4fFDfriqkt5sxx21MYnnA1fiVuyC3kY+OloApYOI0aWIUd41pFoGXIZLKPqM5Ad 9ykv2fpTvtKKa5jK+qwkr+FINX5NK80V1ll6y8M7lf+5PYIqVla9voQWwaId4nBrbR6x NFvVE71MLNb3pLNSELT0pmyeWJLBtY9svEHH5rGuB8ntn9mGz6uJx+/QIgbQM5ZInmYz dmqKxnUpFV6s4Y4RBWhQXTdxco2DxVMP+JgHH7bFbD9aVwT1HObOKR2v4CnbA6GSCBAl T+0qQRldKSCgluAlCzrMtMQZg6smZiWPTglz10EmNgbPhrf9IdCpU046cPTT+3Wq7OVx +2Xg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=qB8cosFg/V+ZgSCX/jWtnk8u0ihozSaIQH9qUkXCmZ8=; b=BPzs48lcIah6HAPU4Xc+v8b5NBbcuHo9rL0NOvjPjn1orhGfwwntAvA1V9nFD2sMi2 tYwjjYZ/a+ZNBEhWgk7EcjZ38S7otrvTOVvKJ/AN5m+c2xpbEGP5OLHsBv3MfVSg3YOe 0w+UBkVg/uxxS52f2zIrntiHyHDc8yfcxNr8DDf5DKLgaWkoTM2AsncF+4hsNAjaGjAl X7rtKOlYJtFb8FMZrV8dEIKiacZGs0CSdFRJU8c20v3pszlQxi/VJw5Fl3+L27qiLpT1 XycofSxg3KnikGf+AmPZqjRyFOZfopmnmy7fo5VGm+phT8YMUbaetDNq7c2TBCNsMJ/s Aswg== X-Gm-Message-State: ANhLgQ3wkV6fimKDwntmdd9PlG7W6ZE/USGU06HIMHS2iDUcPoQozvjF X9wI2YtKFeukzNtiIMw+88M= X-Google-Smtp-Source: ADFU+vsRwR770XERm2dqpUS53+O2WhjY/szqYi+ItkIxiN7V57yGQAoGr0ENzncjT5r2cA1niJ/j8A== X-Received: by 2002:a63:d143:: with SMTP id c3mr25424121pgj.171.1585036649668; Tue, 24 Mar 2020 00:57:29 -0700 (PDT) Received: from localhost.corp.microsoft.com ([167.220.2.210]) by smtp.googlemail.com with ESMTPSA id x71sm15452076pfd.129.2020.03.24.00.57.28 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 24 Mar 2020 00:57:29 -0700 (PDT) From: ltykernel@gmail.com X-Google-Original-From: Tianyu.Lan@microsoft.com To: kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, liuwe@microsoft.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, michael.h.kelley@microsoft.com Cc: Tianyu Lan , linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, vkuznets@redhat.com Subject: [PATCH V3 3/6] x86/Hyper-V: Trigger crash enlightenment only once during system crash. Date: Tue, 24 Mar 2020 00:57:17 -0700 Message-Id: <20200324075720.9462-4-Tianyu.Lan@microsoft.com> X-Mailer: git-send-email 2.14.5 In-Reply-To: <20200324075720.9462-1-Tianyu.Lan@microsoft.com> References: <20200324075720.9462-1-Tianyu.Lan@microsoft.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tianyu Lan When a guest VM panics, Hyper-V should be notified only once via the crash synthetic MSRs. Current Linux code might write these crash MSRs twice during a system panic: 1) hyperv_panic/die_event() calling hyperv_report_panic() 2) hv_kmsg_dump() calling hyperv_report_panic_msg() Fix this by not calling hyperv_report_panic() if a kmsg dump has been successfully registered. The notification will happen later via hyperv_report_panic_msg(). Signed-off-by: Tianyu Lan --- Change since v1: - Update commit log Change since v2: - Update comment --- drivers/hv/vmbus_drv.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 00a511f15926..333dad39b1c1 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -55,7 +55,13 @@ static int hyperv_panic_event(struct notifier_block *nb, unsigned long val, vmbus_initiate_unload(true); - if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { + /* + * Hyper-V should be notified only once about a panic. If we will be + * doing hyperv_report_panic_msg() later with kmsg data, don't do + * the notification here. + */ + if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE + && !hv_panic_page) { regs = current_pt_regs(); hyperv_report_panic(regs, val); } @@ -68,7 +74,13 @@ static int hyperv_die_event(struct notifier_block *nb, unsigned long val, struct die_args *die = (struct die_args *)args; struct pt_regs *regs = die->regs; - hyperv_report_panic(regs, val); + /* + * Hyper-V should be notified only once about a panic. If we will be + * doing hyperv_report_panic_msg() later with kmsg data, don't do + * the notification here. + */ + if (!hv_panic_page) + hyperv_report_panic(regs, val); return NOTIFY_DONE; } -- 2.14.5