From patchwork Mon Feb 27 10:49:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Borislav Petkov X-Patchwork-Id: 61904 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:5915:0:0:0:0:0 with SMTP id v21csp2348113wrd; Mon, 27 Feb 2023 02:59:39 -0800 (PST) X-Google-Smtp-Source: AK7set8it9qL9Ljrk19eLniiXO0U9PEUNARKi4QisFpjvshts5aseHWTC3WO3UklfHfGTv+/vZ70 X-Received: by 2002:a05:6a20:7348:b0:cc:fdfa:9091 with SMTP id v8-20020a056a20734800b000ccfdfa9091mr6206295pzc.57.1677495578787; Mon, 27 Feb 2023 02:59:38 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1677495578; cv=none; d=google.com; s=arc-20160816; b=llG2fbBDUe2TB6tPGhx3BL7Bmkj+c9B1KAN6RuMlFPUsR/QjGQS8/lhwHjVe77m+P+ 910Xz4LHF/ueN8kpff/XuEvCr3JXSr/d3GhTFxORoUxl2Ft0Wz3ekKj3E6GNoAGBe+IP YlcqTx+B9EVrYm+StKAxm4l4PzTz/vYJY/77v1dRwgGz1H3hA5SXSXVPuvt/RtmFRqic o2tAwMzX5Eq0PMQhSZgA0k920jIdsYToYogAb68kERcP/1dHPd4F4eOMV0K/diE/LZTY fVmcFg/mMT6UoyspJegEvpmdYBFhjkFv4k66p/C7NE/n5PVBnKBjVq8o6Zzy/ubTIOZk H86A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:in-reply-to:content-disposition:mime-version :references:message-id:subject:cc:to:from:date:dkim-signature; bh=VqxU85nvGdlx9Pi4HtTodVA4yIqLoYPSlLVaoO/N2Do=; b=N76KlAOBdn+Vex/yHm80XbrBqQFYdYUp94JR2Ry3YoCqUpTQPeNYiNXjm07V+xEW1z ceR4yS/a/sZWb2UfVisywn+uFOMcRUJ2/xhDl//IaKGC3AVTD19tlRNF281FJt5rgKlJ +sWFdVRAWB9a0syXRaHNrq0Ay9Z/PCiongSZmE/rPocFR4B5xPRiwFte4wN+RGn/48ZV gyqka2KI1rZ7RCpbNLqSYntyer2eTetua3Z+UNqAJ7dyclZW1ojUhmZExxEWL+cgtZw/ cW51TzZJxmowkNBNvRlYliO7JD9lKu8aJ/FqG7jfHeoKWl99JzCaMheWOAVCdQXz5fPT Uq1g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@alien8.de header.s=dkim header.b="YmX/FITr"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=alien8.de Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id k16-20020aa79730000000b005dce74c3014si6508052pfg.209.2023.02.27.02.59.25; Mon, 27 Feb 2023 02:59:38 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@alien8.de header.s=dkim header.b="YmX/FITr"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=alien8.de Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229806AbjB0KuD (ORCPT + 99 others); Mon, 27 Feb 2023 05:50:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229545AbjB0KuC (ORCPT ); Mon, 27 Feb 2023 05:50:02 -0500 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0735CA2A for ; Mon, 27 Feb 2023 02:49:59 -0800 (PST) Received: from zn.tnic (p5de8e9fe.dip0.t-ipconnect.de [93.232.233.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 464391EC053F; Mon, 27 Feb 2023 11:49:58 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1677494998; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=VqxU85nvGdlx9Pi4HtTodVA4yIqLoYPSlLVaoO/N2Do=; b=YmX/FITrS7OKTjO5iWm0Xz43PAzyZO3N9tb7SIfyeq1my5m2M0pobMDlLoO9Y+O5M69eQn DMl6VmppzespU/nATIM9qvOoCoRwhSFBMQ2g4dEoi+aUEVQw+nnfNyE83BdTor3gdmm8Om bG17rgBYIjGv6nICrZZESboE91Jcq6I= Date: Mon, 27 Feb 2023 11:49:53 +0100 From: Borislav Petkov To: Peter Zijlstra Cc: x86@kernel.org, linux-kernel@vger.kernel.org, mhiramat@kernel.org, kirill.shutemov@linux.intel.com, Andrew.Cooper3@citrix.com, jpoimboe@redhat.com, Daniel Verkamp , Jiri Slaby , Tony Luck Subject: [PATCH] x86/lib/memmove: Decouple ERMS from FSRM Message-ID: References: <20230208171050.490809180@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230208171050.490809180@infradead.org> X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1758981604359325016?= X-GMAIL-MSGID: =?utf-8?q?1758981604359325016?= On Wed, Feb 08, 2023 at 06:10:50PM +0100, Peter Zijlstra wrote: > Hi, > > This version is fully tested and includes a few NOP twiddles inspired by the > objtool patches I'll post separately. > > Also available at: > > https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/log/?h=x86/core Ontop of the first two: From: "Borislav Petkov (AMD)" Date: Sun, 26 Feb 2023 21:04:26 +0100 Subject: [PATCH] x86/lib/memmove: Decouple ERMS from FSRM Up until now it was perceived that FSRM is an improvement to ERMS and thus it was made dependent on latter. However, there are AMD BIOSes out there which allow for disabling of either features and this preventing kernels from booting due to the CMP disappearing and thus breaking the logic in the memmove() function. Similar observation happens on some VM migration scenarios. Patch the proper sequences depending on which feature is enabled. Signed-off-by: Borislav Petkov (AMD) Reported-by: Daniel Verkamp Reported-by: Jiri Slaby Tested-by: Yahu Gao gaoyh12@lenove.com --- arch/x86/lib/memmove_64.S | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/arch/x86/lib/memmove_64.S b/arch/x86/lib/memmove_64.S index 02661861e5dd..0559b206fb11 100644 --- a/arch/x86/lib/memmove_64.S +++ b/arch/x86/lib/memmove_64.S @@ -38,10 +38,12 @@ SYM_FUNC_START(__memmove) cmp %rdi, %r8 jg 2f - /* FSRM implies ERMS => no length checks, do the copy directly */ +#define CHECK_LEN cmp $0x20, %rdx; jb 1f +#define MEMMOVE_BYTES movq %rdx, %rcx; rep movsb; RET .Lmemmove_begin_forward: - ALTERNATIVE "cmp $0x20, %rdx; jb 1f", "", X86_FEATURE_FSRM - ALTERNATIVE "", "jmp .Lmemmove_erms", X86_FEATURE_ERMS + ALTERNATIVE_2 __stringify(CHECK_LEN), \ + __stringify(CHECK_LEN; MEMMOVE_BYTES), X86_FEATURE_ERMS, \ + __stringify(MEMMOVE_BYTES), X86_FEATURE_FSRM /* * movsq instruction have many startup latency @@ -207,11 +209,6 @@ SYM_FUNC_START(__memmove) movb %r11b, (%rdi) 13: RET - -.Lmemmove_erms: - movq %rdx, %rcx - rep movsb - RET SYM_FUNC_END(__memmove) EXPORT_SYMBOL(__memmove)