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=-3.7 required=3.0 tests=BAYES_00, 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 DEBF0C433ED for ; Wed, 19 May 2021 11:33:58 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5E87C611C2 for ; Wed, 19 May 2021 11:33:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5E87C611C2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=8bytes.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=virtualization-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 1321A605C8; Wed, 19 May 2021 11:33:58 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 9fL0pooYrBBn; Wed, 19 May 2021 11:33:56 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp3.osuosl.org (Postfix) with ESMTP id D4C9360772; Wed, 19 May 2021 11:33:55 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 9CA4DC000E; Wed, 19 May 2021 11:33:55 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [IPv6:2605:bc80:3010::138]) by lists.linuxfoundation.org (Postfix) with ESMTP id 57AB3C0001 for ; Wed, 19 May 2021 11:33:54 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 3950F831F1 for ; Wed, 19 May 2021 11:33:54 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 5pidh9bjSzvq for ; Wed, 19 May 2021 11:33:52 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from theia.8bytes.org (8bytes.org [IPv6:2a01:238:4383:600:38bc:a715:4b6d:a889]) by smtp1.osuosl.org (Postfix) with ESMTPS id A05BE82C9D for ; Wed, 19 May 2021 11:33:52 +0000 (UTC) Received: by theia.8bytes.org (Postfix, from userid 1000) id 689F82FA; Wed, 19 May 2021 13:33:48 +0200 (CEST) Date: Wed, 19 May 2021 13:33:46 +0200 From: 'Joerg Roedel' To: Joerg Roedel Subject: Re: [PATCH 3/6] x86/sev-es: Use __put_user()/__get_user Message-ID: References: <20210512075445.18935-1-joro@8bytes.org> <20210512075445.18935-4-joro@8bytes.org> <0496626f018d4d27a8034a4822170222@AcuMS.aculab.com> <92244e37-4443-98bd-24aa-bf59548aab47@suse.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Cc: "kvm@vger.kernel.org" , Peter Zijlstra , Dave Hansen , "virtualization@lists.linux-foundation.org" , Arvind Sankar , "hpa@zytor.com" , Jiri Slaby , "x86@kernel.org" , David Rientjes , Martin Radev , Tom Lendacky , Kees Cook , Cfir Cohen , Hyunwook Baek , "linux-coco@lists.linux.dev" , Andy Lutomirski , Dan Williams , Juergen Gross , Mike Stunes , Sean Christopherson , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , David Laight , Masami Hiramatsu , Erdem Aktas X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" On Wed, May 12, 2021 at 11:32:35AM +0200, Joerg Roedel wrote: > On Wed, May 12, 2021 at 10:58:20AM +0200, Juergen Gross wrote: > > No, those were used before, but commit 9da3f2b7405440 broke Xen's use > > case. That is why I did commit 1457d8cf7664f. > > [...] > > Having the distinction between user and kernel memory accesses > explicitly in the code seems to be the most robust solution. On the other hand, as I found out today, 9da3f2b7405440 had a short life-time and got reverted upstream. So using __get_user()/__put_user() should be fine in this code path. It just deserves a comment explaining its use here and why pagefault_enable()/disable() is not needed. Even the get_kernel* helpers use __get_user_size() internally. Regards, Joerg _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization