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=-5.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, USER_AGENT_MUTT 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 1F44BC43381 for ; Thu, 7 Mar 2019 12:32:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D807520643 for ; Thu, 7 Mar 2019 12:32:46 +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="B60hfypX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726259AbfCGMcp (ORCPT ); Thu, 7 Mar 2019 07:32:45 -0500 Received: from merlin.infradead.org ([205.233.59.134]:51354 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726127AbfCGMco (ORCPT ); Thu, 7 Mar 2019 07:32:44 -0500 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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=x3s5JOKP4qCXZzU4hjE9cM90uEEJWbBvF2xoIeQgxGI=; b=B60hfypXvswHvJZt1sYbWI/LM 5+O2fKYAa5GL9aQfkTowzSD1ixFh18g5FoBe/LdXArTqyUnatIPZlY6/RSvJHpZ9GeJTMOVUowvnd qdihvNnRlCzLH3IvCfjo4mh9/qX7RttEqholXtdBkGNyHHiCrIKu2TaMOJBfGStup0qoCBrRrnKzv MbpYszB2m5rcft1/2jFq9JabaRadhuCCJLflmzBCbh/Eg5cFYXIYLhn1dUW7o8xv30UGluPgYlse3 uD+WRLuhqNTm/ZUqJ0P8SZz92YX2OpdeXbwvbpXL3y4XzgDBD32X328tN+ABeukNDJ3SNAbfzR5YV A6+dB0vHA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1h1sBu-0005dy-Gp; Thu, 07 Mar 2019 12:32:06 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id EFA6F20297BC0; Thu, 7 Mar 2019 13:32:00 +0100 (CET) Date: Thu, 7 Mar 2019 13:32:00 +0100 From: Peter Zijlstra To: Juergen Gross Cc: torvalds@linux-foundation.org, tglx@linutronix.de, hpa@zytor.com, julien.thierry@arm.com, will.deacon@arm.com, luto@amacapital.net, mingo@kernel.org, catalin.marinas@arm.com, james.morse@arm.com, valentin.schneider@arm.com, brgerst@gmail.com, jpoimboe@redhat.com, luto@kernel.org, bp@alien8.de, dvlasenk@redhat.com, linux-kernel@vger.kernel.org, dvyukov@google.com, rostedt@goodmis.org, andrew.cooper3@citrix.com, Boris Ostrovsky , Stefano Stabellini Subject: Re: [PATCH 05/20] x86/uaccess/xen: Suppress SMAP warnings Message-ID: <20190307123200.GE32477@hirez.programming.kicks-ass.net> References: <20190307114511.870090179@infradead.org> <20190307115159.530608243@infradead.org> <689d6dc2-77d6-018e-b156-979b2724be7b@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <689d6dc2-77d6-018e-b156-979b2724be7b@suse.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 07, 2019 at 01:22:52PM +0100, Juergen Gross wrote: > On 07/03/2019 12:45, Peter Zijlstra wrote: > > drivers/xen/privcmd.o: warning: objtool: privcmd_ioctl()+0x1414: call to hypercall_page() with UACCESS enabled > > > > Xen needs to do HV calls with AC=1 for hysterical raisins. Make the > > warning go away. > > No, this is a hypercall with parameters passed through from user land > (Xen tools). So setting AC=1 is not related to hysterical reasons, but > to indicate that unprivileged buffers are okay here. So please change > the commit message to something like: > > Some Xen hypercalls allow parameter buffers in user land, so they need > to set AC=1. Avoid the warning for those cases. *yuck* that's gross... And I understood from Andrew yesterday (but perhaps I misunderstood) that the whole privcmd thing was a bit of a hack. But sure, I'll change the message. > > XXX: arguably we should rename ANNOTATE_NOSPEC_ALTERNATIVE to > > ANNOTATE_IGNORE_ALTERNATIVE. > > > > Cc: andrew.cooper3@citrix.com > > Signed-off-by: Peter Zijlstra (Intel) > > Mind Cc-ing the maintainers of the code you are touching in future > patches? Sure; my bad, I forgot to ask get_maintainers about this.