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=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 3FC33C433E0 for ; Wed, 5 Aug 2020 19:54:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1B0F422B42 for ; Wed, 5 Aug 2020 19:54:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="xZgN77rc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729480AbgHETyi (ORCPT ); Wed, 5 Aug 2020 15:54:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46168 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727103AbgHEQsj (ORCPT ); Wed, 5 Aug 2020 12:48:39 -0400 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D035C0A893D for ; Wed, 5 Aug 2020 07:13:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=RIIneg+7/mEtbE19meMAOfaXXJsMYVcX3DCzixtwFp4=; b=xZgN77rc7QTu2SUz2Txvp07BQa rEKwKgC5ctZBRSV40lDEvZPvCZt5LmfeV/pyQOmnZC6mdVXAcchmO14bFXVpo3vNwueBX+BKFPz14 f3/FLmbDBzST8oOh2reniGLLG9o+E1Ce7vjg6GOkTdUF+fQZiWJ9F00Wkv+lyojL6bu8DUzqsLlUx eS124XSyfJ6v5oa2y7SUVKVHMHUjRsHW1rss0vou12PBoO3y4ruAdOXLDdQounpE76OtzNK7a5JeY JNab3EZGOKfbwCt7HaeJUJEm5q3n4ieRvin6IaqQqHS17pXADia68KF231yRUFKPInlpMI0WxtlyC GXTIOgJw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1k3K9p-0000Mo-TQ; Wed, 05 Aug 2020 14:12:42 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id B13C7301E02; Wed, 5 Aug 2020 16:12:37 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id A584823D7A30F; Wed, 5 Aug 2020 16:12:37 +0200 (CEST) Date: Wed, 5 Aug 2020 16:12:37 +0200 From: peterz@infradead.org To: Marco Elver Cc: bp@alien8.de, dave.hansen@linux.intel.com, fenghua.yu@intel.com, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, tony.luck@intel.com, x86@kernel.org, yu-cheng.yu@intel.com, jgross@suse.com, sdeep@vmware.com, virtualization@lists.linux-foundation.org, kasan-dev@googlegroups.com, syzbot Subject: Re: [PATCH] x86/paravirt: Add missing noinstr to arch_local*() helpers Message-ID: <20200805141237.GS2674@hirez.programming.kicks-ass.net> References: <0000000000007d3b2d05ac1c303e@google.com> <20200805132629.GA87338@elver.google.com> <20200805134232.GR2674@hirez.programming.kicks-ass.net> <20200805135940.GA156343@elver.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200805135940.GA156343@elver.google.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 05, 2020 at 03:59:40PM +0200, Marco Elver wrote: > On Wed, Aug 05, 2020 at 03:42PM +0200, peterz@infradead.org wrote: > > Shouldn't we __always_inline those? They're going to be really small. > > I can send a v2, and you can choose. For reference, though: > > ffffffff86271ee0 : > ffffffff86271ee0: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > ffffffff86271ee5: 48 83 3d 43 87 e4 01 cmpq $0x0,0x1e48743(%rip) # ffffffff880ba630 > ffffffff86271eec: 00 > ffffffff86271eed: 74 0d je ffffffff86271efc > ffffffff86271eef: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > ffffffff86271ef4: ff 14 25 30 a6 0b 88 callq *0xffffffff880ba630 > ffffffff86271efb: c3 retq > ffffffff86271efc: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > ffffffff86271f01: 0f 0b ud2 > ffffffff86271a90 : > ffffffff86271a90: 53 push %rbx > ffffffff86271a91: 48 89 fb mov %rdi,%rbx > ffffffff86271a94: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > ffffffff86271a99: 48 83 3d 97 8b e4 01 cmpq $0x0,0x1e48b97(%rip) # ffffffff880ba638 > ffffffff86271aa0: 00 > ffffffff86271aa1: 74 11 je ffffffff86271ab4 > ffffffff86271aa3: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > ffffffff86271aa8: 48 89 df mov %rbx,%rdi > ffffffff86271aab: ff 14 25 38 a6 0b 88 callq *0xffffffff880ba638 > ffffffff86271ab2: 5b pop %rbx > ffffffff86271ab3: c3 retq > ffffffff86271ab4: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > ffffffff86271ab9: 0f 0b ud2 Blergh, that's abysmall. In part I suspect because you have CONFIG_PARAVIRT_DEBUG, let me try and untangle that PV macro maze.