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=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 C13BCC2BA83 for ; Wed, 12 Feb 2020 12:28:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 931EC20675 for ; Wed, 12 Feb 2020 12:28:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="RUCBPiK0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727669AbgBLM2z (ORCPT ); Wed, 12 Feb 2020 07:28:55 -0500 Received: from mail-wm1-f65.google.com ([209.85.128.65]:40291 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725887AbgBLM2y (ORCPT ); Wed, 12 Feb 2020 07:28:54 -0500 Received: by mail-wm1-f65.google.com with SMTP id t14so2172242wmi.5; Wed, 12 Feb 2020 04:28:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id; bh=t4Q1OJdYjIIxxl8hiEppJFQjj2ZAX1Z78z3H6fI5ihw=; b=RUCBPiK0KzfTLbmBjqf58NyLqNYH8NtZ4mYkYKzY5lQu1o5xBjeGMK4pVCUodMm3c5 AGq95P3KX2+llMuF/JbBEGqXbZspUek0Odh3FQSb42+fyn+MyNcyJzSg7Fm+SWtjrH8W AvcDfNPAYi1Z1wK8X2nEWVnQvJ+uNzFVJKAMUEWUHaPk2PfJtpPcMWvqWNr+EqbgH303 VLMouazPFSKoWavfXIUxlKL7V44b1pukn32iLJul+kx/7ccUFFN7SP5dNyRCocE0u+yo 2TBqdr/h7dLju9WUYy8oe7ErTNIGoXPvau+FW5Dnv9gsbwl7MLKUf6LbL0OUX9utcgmY OIXg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id; bh=t4Q1OJdYjIIxxl8hiEppJFQjj2ZAX1Z78z3H6fI5ihw=; b=eGceuNU4JX1rbTUQfW0X6eEJYueNt39DkcD08foMi0/2YrZPtBWSayLH1T7+8CURPu WN8subWQO0FMepwPhFHTX1h8myO1en2ySFixzWJdrtReYkCnbp74MhQhOQRzJD5ikgGO Ya6lSMHlLEPCV4X2rzl5xKe9BEw4VMnaBBHBTd5QSd1uvBZbsxhIPbyqAOr9imEOk5gG tqtK/K0Ivjqo0ckdbpY0DHMp3eQyyXlpq3TbMkMt+xHbpuMjEmIac/x08MHqx9NiDAv3 rceeAOmuISm50yFl6r8caSJjtZPm5evISoePiiZTmcbObh8NDR7e0CKMf1vRyOkVqrcR ECTQ== X-Gm-Message-State: APjAAAUCK570NsXXCQkWZdExWx3XU2TQ5k014q6pBG7XIlr7zZ5joRQR ZLkJ4vHq2oigDw7MB/uupMn6kq8K X-Google-Smtp-Source: APXvYqyzRtoVd0HNOXCQ12XYPRhWe0kHrAmc7+K+dCm+eaNdrx1pFvWCt6rcZIsMbwMR/JvCy3SMGA== X-Received: by 2002:a1c:1b93:: with SMTP id b141mr13172375wmb.114.1581510531962; Wed, 12 Feb 2020 04:28:51 -0800 (PST) Received: from 640k.lan ([93.56.166.5]) by smtp.gmail.com with ESMTPSA id 59sm522255wre.29.2020.02.12.04.28.50 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 12 Feb 2020 04:28:50 -0800 (PST) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: colin.king@canonical.com, sean.j.christopherson@intel.com Subject: [PATCH] KVM: x86: fix WARN_ON check of an unsigned less than zero Date: Wed, 12 Feb 2020 13:28:48 +0100 Message-Id: <1581510528-19303-1-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.8.3.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The check cpu->hv_clock.system_time < 0 is redundant since system_time is a u64 and hence can never be less than zero. But what was actually meant is to check that the result is positive, since kernel_ns and v->kvm->arch.kvmclock_offset are both s64. Reported-by: Colin King Suggested-by: Sean Christopherson Addresses-Coverity: ("Macro compares unsigned to 0") Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 54e8142b15d0..359fcd395132 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2444,7 +2444,7 @@ static int kvm_guest_time_update(struct kvm_vcpu *v) vcpu->hv_clock.tsc_timestamp = tsc_timestamp; vcpu->hv_clock.system_time = kernel_ns + v->kvm->arch.kvmclock_offset; vcpu->last_guest_tsc = tsc_timestamp; - WARN_ON(vcpu->hv_clock.system_time < 0); + WARN_ON((s64)vcpu->hv_clock.system_time < 0); /* If the host uses TSC clocksource, then it is stable */ pvclock_flags = 0; -- 1.8.3.1