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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B4E3FA3740 for ; Thu, 27 Oct 2022 17:01:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236819AbiJ0RB3 (ORCPT ); Thu, 27 Oct 2022 13:01:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54460 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236824AbiJ0RB2 (ORCPT ); Thu, 27 Oct 2022 13:01:28 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DD50A189C25 for ; Thu, 27 Oct 2022 10:01:27 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 90CB9B82717 for ; Thu, 27 Oct 2022 17:01:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7E40C433D7; Thu, 27 Oct 2022 17:01:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666890085; bh=RJsFw6x0qVMXLnDTATO+MZ2CvG1OYgeoqVfzs/RiNDs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jozCkbYrzgqDFKbvJRkwxJaWNHjPwoL6P9GxbtHT2NUyBS6jswEJ4WOMjKgml+CtT SIPUdgPhYmgqQJFdVd55tHpsiyZbQt7Dd2DlUDjCNgJpfJNhRoUVtQDMYW9iudSNVK PS1U16te2XJtSnTzQGp9bucTvYrN3XENpwqrXZ4c= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?=C8=98tefan=20Talpalaru?= , Borislav Petkov Subject: [PATCH 5.15 17/79] x86/microcode/AMD: Apply the patch early on every logical thread Date: Thu, 27 Oct 2022 18:55:15 +0200 Message-Id: <20221027165055.533689538@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221027165054.917467648@linuxfoundation.org> References: <20221027165054.917467648@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Borislav Petkov commit e7ad18d1169c62e6c78c01ff693fd362d9d65278 upstream. Currently, the patch application logic checks whether the revision needs to be applied on each logical CPU (SMT thread). Therefore, on SMT designs where the microcode engine is shared between the two threads, the application happens only on one of them as that is enough to update the shared microcode engine. However, there are microcode patches which do per-thread modification, see Link tag below. Therefore, drop the revision check and try applying on each thread. This is what the BIOS does too so this method is very much tested. Btw, change only the early paths. On the late loading paths, there's no point in doing per-thread modification because if is it some case like in the bugzilla below - removing a CPUID flag - the kernel cannot go and un-use features it has detected are there early. For that, one should use early loading anyway. [ bp: Fixes does not contain the oldest commit which did check for equality but that is good enough. ] Fixes: 8801b3fcb574 ("x86/microcode/AMD: Rework container parsing") Reported-by: Ștefan Talpalaru Signed-off-by: Borislav Petkov Tested-by: Ștefan Talpalaru Cc: Link: https://bugzilla.kernel.org/show_bug.cgi?id=216211 Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/microcode/amd.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) --- a/arch/x86/kernel/cpu/microcode/amd.c +++ b/arch/x86/kernel/cpu/microcode/amd.c @@ -440,7 +440,13 @@ apply_microcode_early_amd(u32 cpuid_1_ea return ret; native_rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy); - if (rev >= mc->hdr.patch_id) + + /* + * Allow application of the same revision to pick up SMT-specific + * changes even if the revision of the other SMT thread is already + * up-to-date. + */ + if (rev > mc->hdr.patch_id) return ret; if (!__apply_microcode_amd(mc)) { @@ -522,8 +528,12 @@ void load_ucode_amd_ap(unsigned int cpui native_rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy); - /* Check whether we have saved a new patch already: */ - if (*new_rev && rev < mc->hdr.patch_id) { + /* + * Check whether a new patch has been saved already. Also, allow application of + * the same revision in order to pick up SMT-thread-specific configuration even + * if the sibling SMT thread already has an up-to-date revision. + */ + if (*new_rev && rev <= mc->hdr.patch_id) { if (!__apply_microcode_amd(mc)) { *new_rev = mc->hdr.patch_id; return;