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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2608DC25B6B for ; Thu, 26 Oct 2023 09:42:44 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.623635.971660 (Exim 4.92) (envelope-from ) id 1qvwso-0007fU-Kq; Thu, 26 Oct 2023 09:42:30 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 623635.971660; Thu, 26 Oct 2023 09:42:30 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qvwso-0007fN-Hj; Thu, 26 Oct 2023 09:42:30 +0000 Received: by outflank-mailman (input) for mailman id 623635; Thu, 26 Oct 2023 09:42:29 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qvwsn-0007fH-Ii for xen-devel@lists.xenproject.org; Thu, 26 Oct 2023 09:42:29 +0000 Received: from support.bugseng.com (mail.bugseng.com [162.55.131.47]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id f93dc3aa-73e3-11ee-9b0e-b553b5be7939; Thu, 26 Oct 2023 11:42:27 +0200 (CEST) Received: from support.bugseng.com (support.bugseng.com [162.55.131.47]) by support.bugseng.com (Postfix) with ESMTPA id C75E44EE0742; Thu, 26 Oct 2023 11:42:26 +0200 (CEST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: f93dc3aa-73e3-11ee-9b0e-b553b5be7939 MIME-Version: 1.0 Date: Thu, 26 Oct 2023 11:42:26 +0200 From: Nicola Vetrini To: Stefano Stabellini Cc: Jan Beulich , michal.orzel@amd.com, xenia.ragiadakou@amd.com, ayan.kumar.halder@amd.com, consulting@bugseng.com, andrew.cooper3@citrix.com, roger.pau@citrix.com, Wei Liu , Jun Nakajima , Kevin Tian , xen-devel@lists.xenproject.org Subject: Re: [XEN PATCH][for-4.19 v4 3/8] x86: add deviation comments for asm-only functions In-Reply-To: References: <36d24b3a3e264f0e0b265b4f68d6432a143d64cd.1698053876.git.nicola.vetrini@bugseng.com> <2d92ef1f753165e2fa9cc7c04c219217@bugseng.com> <52422128-156d-5d6c-46b2-261b1c7e85c0@suse.com> <734cc13409b44f709649895d76d388e2@bugseng.com> User-Agent: Roundcube Webmail/1.4.3 Message-ID: <843362b110e38fcddf5d0c4b1ff95099@bugseng.com> X-Sender: nicola.vetrini@bugseng.com Organization: BUGSENG s.r.l. Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit On 26/10/2023 00:36, Stefano Stabellini wrote: > On Wed, 25 Oct 2023, Nicola Vetrini wrote: >> On 24/10/2023 21:50, Stefano Stabellini wrote: >> > On Tue, 24 Oct 2023, Nicola Vetrini wrote: >> > > On 24/10/2023 10:14, Jan Beulich wrote: >> > > > On 24.10.2023 10:01, Nicola Vetrini wrote: >> > > > > On 24/10/2023 09:50, Jan Beulich wrote: >> > > > > > On 23.10.2023 11:56, Nicola Vetrini wrote: >> > > > > > > As stated in rules.rst, functions used only in asm code >> > > > > > > are allowed to have no prior declaration visible when being >> > > > > > > defined, hence these functions are deviated. >> > > > > > > This also fixes violations of MISRA C:2012 Rule 8.4. >> > > > > > > >> > > > > > > Signed-off-by: Nicola Vetrini >> > > > > > > Reviewed-by: Stefano Stabellini >> > > > > > > --- >> > > > > > > Changes in v3: >> > > > > > > - added SAF deviations for vmx counterparts to svm functions. >> > > > > > >> > > > > > Same comment regarding the R-b here as for patch 2. >> > > > > > >> > > > > > > --- a/xen/arch/x86/hvm/svm/intr.c >> > > > > > > +++ b/xen/arch/x86/hvm/svm/intr.c >> > > > > > > @@ -123,6 +123,7 @@ static void svm_enable_intr_window(struct vcpu >> > > *v, >> > > > > > > struct hvm_intack intack) >> > > > > > > vmcb, general1_intercepts | GENERAL1_INTERCEPT_VINTR); >> > > > > > > } >> > > > > > > >> > > > > > > +/* SAF-1-safe */ >> > > > > > > void svm_intr_assist(void) >> > > > > > > { >> > > > > > > struct vcpu *v = current; >> > > > > > >> > > > > > Linux has the concept of "asmlinkage" for functions interfacing C >> > > and >> > > > > > assembly. Was it considered to use that - even if expanding to >> > > nothing >> > > > > > for all present architectures - as a way to annotate affected >> > > > > > definitions >> > > > > > in place of the SAF-*-safe comments? >> > > > > >> > > > > It was proposed by Julien a while ago (I think it the thread on >> > > > > deviations.rst) to define >> > > > > a macro asmcall that expands to nothing, to mark all such functions. >> > > > > Right now, it's not >> > > > > strictly necessary (given that there are already some uses of SAF in >> > > > > Stefano's for-4.19 branch. >> > > > >> > > > Can this then be revisited please before any such reaches staging? >> > > > >> > > > Jan >> > > >> > > I'll let Stefano answer this one. >> > >> > Yes it can. If Nicola sends new patches I'll make sure to remove the >> > corresponding ones from for-4.19. >> > >> > Nicola, you might want to send me privately the list of commits to take >> > out from for-4.19. >> >> Actually I checked: the involved SAF comments are already in staging, >> specifically all >> were part of commit 5a415ef2b24d578d29479e38abda3d5285b9afed > > OK. In that case we can still use the asmcall macro to deviate/fix new > violations. I suggest we do that. At some point anyone can go ahead and > replace those SAF comments with asmcall macros. Perhaps asmlinkage is a better fit, so that it wouldn't sound strange applying it to variables. -- Nicola Vetrini, BSc Software Engineer, BUGSENG srl (https://bugseng.com)