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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 58AF5C2D0D4 for ; Mon, 10 May 2021 11:20:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3DCBF61042 for ; Mon, 10 May 2021 11:20:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238566AbhEJLSG (ORCPT ); Mon, 10 May 2021 07:18:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:41486 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233051AbhEJKyZ (ORCPT ); Mon, 10 May 2021 06:54:25 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1CE7161933; Mon, 10 May 2021 10:41:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620643309; bh=tr9yYa5f4GwkbODbc3zriXL7cBsTAh7UDLGF811eowE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tEfXclDAqgkkl1szc7aZPF7tfyGGp288mZsjej14vyfJVtD1ZCPIi8IMtMGMHnwHY /KGUV/bcWX4sCq63AVPn5qmCB8lidmiYsR4fEh+jPGupTuSIuS507F/m01yTVgdxCC suCv28XOf4mtL3qVib6f3jcD1rpgnT89ClqzPC+M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sean Christopherson , Thomas Gleixner Subject: [PATCH 5.10 262/299] x86/cpu: Initialize MSR_TSC_AUX if RDTSCP *or* RDPID is supported Date: Mon, 10 May 2021 12:20:59 +0200 Message-Id: <20210510102013.604060138@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210510102004.821838356@linuxfoundation.org> References: <20210510102004.821838356@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sean Christopherson commit b6b4fbd90b155a0025223df2c137af8a701d53b3 upstream. Initialize MSR_TSC_AUX with CPU node information if RDTSCP or RDPID is supported. This fixes a bug where vdso_read_cpunode() will read garbage via RDPID if RDPID is supported but RDTSCP is not. While no known CPU supports RDPID but not RDTSCP, both Intel's SDM and AMD's APM allow for RDPID to exist without RDTSCP, e.g. it's technically a legal CPU model for a virtual machine. Note, technically MSR_TSC_AUX could be initialized if and only if RDPID is supported since RDTSCP is currently not used to retrieve the CPU node. But, the cost of the superfluous WRMSR is negigible, whereas leaving MSR_TSC_AUX uninitialized is just asking for future breakage if someone decides to utilize RDTSCP. Fixes: a582c540ac1b ("x86/vdso: Use RDPID in preference to LSL when available") Signed-off-by: Sean Christopherson Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210504225632.1532621-2-seanjc@google.com Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1847,7 +1847,7 @@ static inline void setup_getcpu(int cpu) unsigned long cpudata = vdso_encode_cpunode(cpu, early_cpu_to_node(cpu)); struct desc_struct d = { }; - if (boot_cpu_has(X86_FEATURE_RDTSCP)) + if (boot_cpu_has(X86_FEATURE_RDTSCP) || boot_cpu_has(X86_FEATURE_RDPID)) write_rdtscp_aux(cpudata); /* Store CPU and node number in limit. */