From nobody Thu Dec 18 08:59:17 2025 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 1D57BC7618E for ; Wed, 26 Apr 2023 17:41:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236152AbjDZRlh (ORCPT ); Wed, 26 Apr 2023 13:41:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60680 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234679AbjDZRlg (ORCPT ); Wed, 26 Apr 2023 13:41:36 -0400 X-Greylist: delayed 219 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Wed, 26 Apr 2023 10:41:34 PDT Received: from mail.cybernetics.com (mail.cybernetics.com [72.215.153.18]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B06AF10C for ; Wed, 26 Apr 2023 10:41:34 -0700 (PDT) X-ASG-Debug-ID: 1682530892-1cf4391215320530001-xx1T2L Received: from cybernetics.com ([10.10.4.126]) by mail.cybernetics.com with ESMTP id dsNGcVgsbSHQHQZD; Wed, 26 Apr 2023 13:41:32 -0400 (EDT) X-Barracuda-Envelope-From: tonyb@cybernetics.com X-ASG-Whitelist: Client DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=cybernetics.com; s=mail; bh=MoGhA43xzvvZ8t2pH9I2y5/awsGm9F2RnX1GrXJNuEU=; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:References:Cc:To:From: Content-Language:Subject:MIME-Version:Date:Message-ID; b=oLeM/ElwziYQWjsUDZZ3 LYmoa3ncBhpfAPF/JpY7sj5FNjOvNEo/4nmPQZYI3oVltpvarxlDSZXYLqIqrKLgUW+HF9eg2xoGP PDslMvd9eTbxMNgzp9VHdYZH2H/c0BkfmcU1L1+gQtpgO0KorASHBwdjMF4UbSbxkoB7mZDa+M= Received: from [10.157.2.224] (HELO [192.168.200.1]) by cybernetics.com (CommuniGate Pro SMTP 7.1.1) with ESMTPS id 12591946; Wed, 26 Apr 2023 13:41:32 -0400 Message-ID: <90428c6d-97f6-794f-8cfd-5b30dd5ed140@cybernetics.com> Date: Wed, 26 Apr 2023 13:41:32 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: [PATCH v2] x86/cpu: fix SME test in stop_this_cpu() Content-Language: en-US X-ASG-Orig-Subj: [PATCH v2] x86/cpu: fix SME test in stop_this_cpu() From: Tony Battersby To: Thomas Gleixner , Dave Hansen , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org Cc: "H. Peter Anvin" , Mario Limonciello , Tom Lendacky , "linux-kernel@vger.kernel.org" , Andi Kleen References: <3817d810-e0f1-8ef8-0bbd-663b919ca49b@cybernetics.com> <87o7nbzn8w.ffs@tglx> <5f8a9cb8-70cf-2a17-cfc4-cb31cb658de4@cybernetics.com> <87y1mey503.ffs@tglx> In-Reply-To: Content-Transfer-Encoding: quoted-printable X-Barracuda-Connect: UNKNOWN[10.10.4.126] X-Barracuda-Start-Time: 1682530892 X-Barracuda-URL: https://10.10.4.122:443/cgi-mod/mark.cgi X-Barracuda-BRTS-Status: 1 X-Virus-Scanned: by bsmtpd at cybernetics.com X-Barracuda-Scan-Msg-Size: 1719 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Check that the CPU supports the desired CPUID leaf before attempting to read it. On Intel, querying an invalid extended CPUID leaf returns the values of the maximum basic CPUID leaf. Depending on the CPU, this could cause the SME test to incorrectly evaluate to true, causing native_wbinvd() to be executed when it should have been skipped (seen on a Supermicro X8DTH-6F board with Intel Xeon X5650). Fixes: 08f253ec3767 ("x86/cpu: Clear SME feature flag when not in use") Cc: # 5.18+ Signed-off-by: Tony Battersby --- Changes since v1: updated title and description. arch/x86/kernel/process.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index b650cde3f64d..26aa32e8f636 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -754,13 +754,15 @@ bool xen_set_default_idle(void) =20 void __noreturn stop_this_cpu(void *dummy) { + struct cpuinfo_x86 *c =3D this_cpu_ptr(&cpu_info); + local_irq_disable(); /* * Remove this CPU: */ set_cpu_online(smp_processor_id(), false); disable_local_APIC(); - mcheck_cpu_clear(this_cpu_ptr(&cpu_info)); + mcheck_cpu_clear(c); =20 /* * Use wbinvd on processors that support SME. This provides support @@ -774,7 +776,8 @@ void __noreturn stop_this_cpu(void *dummy) * Test the CPUID bit directly because the machine might've cleared * X86_FEATURE_SME due to cmdline options. */ - if (cpuid_eax(0x8000001f) & BIT(0)) + if (c->extended_cpuid_level >=3D 0x8000001f && + (cpuid_eax(0x8000001f) & BIT(0))) native_wbinvd(); for (;;) { /* --=20 2.25.1