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,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 70E74C433C1 for ; Wed, 31 Mar 2021 05:31:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 42A17619D6 for ; Wed, 31 Mar 2021 05:31:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233645AbhCaFal (ORCPT ); Wed, 31 Mar 2021 01:30:41 -0400 Received: from zinan.dashjr.org ([192.3.11.21]:43992 "EHLO zinan.dashjr.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229959AbhCaFaL (ORCPT ); Wed, 31 Mar 2021 01:30:11 -0400 X-Greylist: delayed 605 seconds by postgrey-1.27 at vger.kernel.org; Wed, 31 Mar 2021 01:30:11 EDT Received: from ishibashi.lan (unknown [12.190.236.208]) (Authenticated sender: luke-jr) by zinan.dashjr.org (Postfix) with ESMTPSA id 1C9E238A00BD; Wed, 31 Mar 2021 05:18:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dashjr.org; s=zinan; t=1617168003; bh=odLfxRSk012Q4ss7k6SdPrlnMY8Ly0GWSjqsUm/HXEg=; h=From:To:Subject:Date; b=pyI3gUUD3nyZz8z6cbuXpAlIYbTd3Hl+RlTwYwjYpceVR5jMghxUM5kmizp13r70f X6ol980htTqSwb/M2EknLZhuPtgR3p1S3H3rz96ODy1iOXiFgt1EiW48P+QDVexeou 66wn0HRjGgQFoJyWXW3AXH30BxT7jxP4ZEasDmEY= X-Hashcash: 1:25:210331:linux-kernel@vger.kernel.org::X/DK8+IXvmGG5+m8:arMxX X-Hashcash: 1:25:210331:trivial@kernel.org::QPL9MVPaBAbWM0g0:aJzzp X-Hashcash: 1:25:210331:x86@kernel.org::sqvjGCpKHMp4MXe=:cke1d X-Hashcash: 1:25:210331:tglx@linutronix.de::IXst3dn5gGjd5VYQ:a/CKK X-Hashcash: 1:25:210331:mingo@redhat.com::dAE3bLo1JU7NEO1C:VPo9 X-Hashcash: 1:25:210331:bp@alien8.de::mhs+SEPD8UTDXU55:256O From: Luke Dashjr To: linux-kernel@vger.kernel.org, trivial@kernel.org, x86@kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov Subject: [PATCH] arch/x86: Encourage rather than discourage x2apic support Date: Wed, 31 Mar 2021 05:16:41 +0000 User-Agent: KMail/1.9.10 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <202103310516.42497.luke@dashjr.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Multi-core SMP doesn't work on modern Intel CPUs (at least Comet Lake) without x2apic. Unsure users should say Y. Signed-off-by: Luke Dashjr --- arch/x86/Kconfig | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 2792879d398ee..ddb42707bd069 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -446,9 +446,10 @@ config X86_X2APIC This enables x2apic support on CPUs that have this feature. This allows 32-bit apic IDs (so it can support very large systems), - and accesses the local apic via MSRs not via mmio. + and accesses the local apic via MSRs not via mmio. It is also needed + to use multiple cores on modern Intel CPUs. - If you don't know what to do here, say N. + If you don't know what to do here, say Y. config X86_MPPARSE bool "Enable MPS table" if ACPI -- 2.6.23