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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 18196C433DB for ; Mon, 15 Mar 2021 06:56:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D83E864E4A for ; Mon, 15 Mar 2021 06:56:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230002AbhCOGzu (ORCPT ); Mon, 15 Mar 2021 02:55:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37888 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229607AbhCOGzk (ORCPT ); Mon, 15 Mar 2021 02:55:40 -0400 Received: from mail-pf1-x42f.google.com (mail-pf1-x42f.google.com [IPv6:2607:f8b0:4864:20::42f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 02468C061574; Sun, 14 Mar 2021 23:55:40 -0700 (PDT) Received: by mail-pf1-x42f.google.com with SMTP id s21so5976696pfm.1; Sun, 14 Mar 2021 23:55:39 -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; bh=pNjaEjC60Q50gikxhUdZUYYiIOugeurKbAsBaEi4TgQ=; b=lwwxmO78ifaVyeZUWmN3XOkuZbwXbDBvkuTkkBOSMjIa3RcS4ZqRcq4Zv/f5zvAsWK rcI0F9ZuovKEDRMmOeKsWbRAQ3xhfA9Y6Gy251QVoTQk4wDodNLrBnfwC+TxG4HK3KZN iX7h5jrkvbU/X8xYERzsjm0NMMZHjZd3SDgoVMOmuuGT0nUtNt6j2970YWjFUiR5cFME azcYeTZg4yCTWYRslsIH+1m8Oc4N4ji6AZM1yZkBJtp9jeWa4xHtJPuIvPyATavGCL31 SztSbTIYpJDyQk3aQiGFICbuGs2SHByfpuLaExh5YrrtzP2gobnA88FjxrfhQbsgs9Zx N0bA== 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; bh=pNjaEjC60Q50gikxhUdZUYYiIOugeurKbAsBaEi4TgQ=; b=t2bXHCLdbjw0bUw3pCzb4woHziXpTWYfrtdAy/QhsCsOXi2E4YJym/clRa5kgVGnMN MT2mjlmO4vChG3UgVmGps8pM3a/Kyv6KQLJ2e5vk5TsJY/Eslu9kFEtNVFUXcZ8uWGJT 0n+VYbSb+g0fjNCIpAS68sEheY+zZaKEAy6WR8LJJ82iL1+2OPQfoVA6t88cykK+eh6B lDvTvWappHLYOHt39PFR25h0Q4ShUjq0ExsznGnCNTFku+uLM6dpTUvsiTNK2rjTx/62 XIc7vMsoIjtsRSj0zpkMb/fhqSRHM+bvJtOVbt9lZrOzyVk0IM/pvSfLny7EXmGELuho tK3g== X-Gm-Message-State: AOAM5337EK9LZ1wPrnt7OMxwsEmSJVxZDUqlBOCns35r3yYgztzXcYJF 8HN3F1pJYbRcKizEzOwlCZqczxne37M= X-Google-Smtp-Source: ABdhPJx6nLjQ+jnlByTPf5t/X5LY01MFQoPvhbltV13isKRo0OzMMlhpJUIzSW+fXGK7Ka3e3zYkfw== X-Received: by 2002:a63:5c23:: with SMTP id q35mr22171258pgb.418.1615791339092; Sun, 14 Mar 2021 23:55:39 -0700 (PDT) Received: from localhost.localdomain ([103.7.29.6]) by smtp.googlemail.com with ESMTPSA id y20sm12472413pfo.210.2021.03.14.23.55.36 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sun, 14 Mar 2021 23:55:38 -0700 (PDT) From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Mark Rutland , Thomas Gleixner Subject: [PATCH v3] x86/kvm: Fix broken irq restoration in kvm_wait Date: Mon, 15 Mar 2021 14:55:28 +0800 Message-Id: <1615791328-2735-1-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Wanpeng Li After commit 997acaf6b4b59c (lockdep: report broken irq restoration), the guest splatting below during boot: raw_local_irq_restore() called with IRQs enabled WARNING: CPU: 1 PID: 169 at kernel/locking/irqflag-debug.c:10 warn_bogus_irq_restore+0x26/0x30 Modules linked in: hid_generic usbhid hid CPU: 1 PID: 169 Comm: systemd-udevd Not tainted 5.11.0+ #25 RIP: 0010:warn_bogus_irq_restore+0x26/0x30 Call Trace: kvm_wait+0x76/0x90 __pv_queued_spin_lock_slowpath+0x285/0x2e0 do_raw_spin_lock+0xc9/0xd0 _raw_spin_lock+0x59/0x70 lockref_get_not_dead+0xf/0x50 __legitimize_path+0x31/0x60 legitimize_root+0x37/0x50 try_to_unlazy_next+0x7f/0x1d0 lookup_fast+0xb0/0x170 path_openat+0x165/0x9b0 do_filp_open+0x99/0x110 do_sys_openat2+0x1f1/0x2e0 do_sys_open+0x5c/0x80 __x64_sys_open+0x21/0x30 do_syscall_64+0x32/0x50 entry_SYSCALL_64_after_hwframe+0x44/0xae The irqflags handling in kvm_wait() which ends up doing: local_irq_save(flags); safe_halt(); local_irq_restore(flags); which triggered a new consistency checking, we generally expect local_irq_save() and local_irq_restore() to be pared and sanely nested, and so local_irq_restore() expects to be called with irqs disabled. This patch fixes it by playing local_irq_disable()/enable() directly. Cc: Mark Rutland Cc: Thomas Gleixner Signed-off-by: Wanpeng Li --- v2 -> v3: * per Sean's suggestion arch/x86/kernel/kvm.c | 23 ++++++++++------------- 1 file changed, 10 insertions(+), 13 deletions(-) diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 5e78e01..72dbb74 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -836,28 +836,25 @@ static void kvm_kick_cpu(int cpu) static void kvm_wait(u8 *ptr, u8 val) { - unsigned long flags; - if (in_nmi()) return; - local_irq_save(flags); - - if (READ_ONCE(*ptr) != val) - goto out; - /* * halt until it's our turn and kicked. Note that we do safe halt * for irq enabled case to avoid hang when lock info is overwritten * in irq spinlock slowpath and no spurious interrupt occur to save us. */ - if (arch_irqs_disabled_flags(flags)) - halt(); - else - safe_halt(); + if (irqs_disabled()) { + if (READ_ONCE(*ptr) == val) + halt(); + } else { + local_irq_disable(); -out: - local_irq_restore(flags); + if (READ_ONCE(*ptr) == val) + safe_halt(); + + local_irq_enable(); + } } #ifdef CONFIG_X86_32 -- 2.7.4