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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 E98A4C433B4 for ; Tue, 4 May 2021 16:30:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BE3DC61153 for ; Tue, 4 May 2021 16:30:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231796AbhEDQbf (ORCPT ); Tue, 4 May 2021 12:31:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57252 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231644AbhEDQbe (ORCPT ); Tue, 4 May 2021 12:31:34 -0400 Received: from mail-ej1-x630.google.com (mail-ej1-x630.google.com [IPv6:2a00:1450:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A010AC06174A for ; Tue, 4 May 2021 09:30:38 -0700 (PDT) Received: by mail-ej1-x630.google.com with SMTP id y7so14107666ejj.9 for ; Tue, 04 May 2021 09:30:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:cc:subject:message-id:mail-followup-to:references :mime-version:content-disposition:in-reply-to; bh=ctdlXSgA9WB8/LgWtL0CJavRE/GrXThnOTOG0Yn+j2M=; b=PV7H9lwE2fkMD9FY3zZI2IQ1LJUNNJi+MErHVDmQXkw7CP2xrU/TYHlHczAfDm5lVa KDiLaKQ00UK/IHHZuLCrQoUb6nNF2np0jdBgPOKnW02lTxjNCfGGcqjbWs0FnUqtA2bw 4MCLLKv0oasjlveEwIDLg7pD/6kl+SgNCQ9ok= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id :mail-followup-to:references:mime-version:content-disposition :in-reply-to; bh=ctdlXSgA9WB8/LgWtL0CJavRE/GrXThnOTOG0Yn+j2M=; b=L/EEJBoXom37FnG7K8alyGaCwkAJvAUjLAwxXXQcxEWeRpjRyB+cm3c8T3TJTZeI7a 5WS8jIxDfJJiW/QLhhRqUACVTKWkeUnB2XzvMLh+RyBW5KVLYBqqdCj3n5TQ10sHuZmg kv0VXhyHHmFIZ3w5afqeLskzSVkYZYiMsJuopOx+6MRBxi8VLO5aACN934TDyTir8U7D HkQEg94kHT7473poYJkkE8+kSre/E1esd2ZiF7mw6xodf/DhZfgoZGVAXGnJBGb3/x9w nRRP13AhwLTWSQbIzP8E3Lz7sqaUyNeEO/f8Ips51sbaWyOtWo69e9n/6TFTrJyieqAR 3U+Q== X-Gm-Message-State: AOAM533x2sMBuzmsTJXK/yhQSAJpmtskHNH4kA9MMHPuDBRZi79c/bHp YbL+mYFGaHaAhRGNUN/1dBlJaA== X-Google-Smtp-Source: ABdhPJxnDxkwXkTAVEK/PThX9uS74sv8umtjiWwfjWMmVibtFA3GJeFZ5aOd5+yEYTEA4wsXOVzSiw== X-Received: by 2002:a17:906:d145:: with SMTP id br5mr22140782ejb.452.1620145837348; Tue, 04 May 2021 09:30:37 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id kt21sm1615904ejb.5.2021.05.04.09.30.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 May 2021 09:30:36 -0700 (PDT) Date: Tue, 4 May 2021 18:30:34 +0200 From: Daniel Vetter To: Jason Gunthorpe Cc: Greg Kurz , Greg Kroah-Hartman , Christoph Hellwig , Michael Ellerman , Alex Williamson , kvm@vger.kernel.org, David Airlie , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Paul Mackerras , linux-api@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, qemu-devel@nongnu.org, qemu-ppc@nongnu.org Subject: Re: remove the nvlink2 pci_vfio subdriver v2 Message-ID: Mail-Followup-To: Jason Gunthorpe , Greg Kurz , Greg Kroah-Hartman , Christoph Hellwig , Michael Ellerman , Alex Williamson , kvm@vger.kernel.org, David Airlie , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Paul Mackerras , linux-api@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, qemu-devel@nongnu.org, qemu-ppc@nongnu.org References: <20210326061311.1497642-1-hch@lst.de> <20210504142236.76994047@bahia.lan> <20210504152034.18e41ec3@bahia.lan> <20210504155327.GA94750@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210504155327.GA94750@nvidia.com> X-Operating-System: Linux phenom 5.10.32scarlett+ Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, May 04, 2021 at 12:53:27PM -0300, Jason Gunthorpe wrote: > On Tue, May 04, 2021 at 04:23:40PM +0200, Daniel Vetter wrote: > > > Just my 2cents from drm (where we deprecate old gunk uapi quite often): > > Imo it's best to keep the uapi headers as-is, but exchange the > > documentation with a big "this is removed, never use again" warning: > > We in RDMA have been doing the opposite, the uapi headers are supposed > to reflect the current kernel. This helps make the kernel > understandable. > > When userspace needs backwards compat to ABI that the current kernel > doesn't support then userspace has distinct copies of that information > in some compat location. It has happened a few times over the last 15 > years. > > We keep full copies of the current kernel headers in the userspace > source tree, when the kernel headers change in a compile incompatible > way we fix everything while updating to the new kernel headers. Yeah we do the same since forever (it's either from libdrm package, or directly in the corresponding userspace header). So largely include/uapi is for documentation > > - it's good to know which uapi numbers (like parameter extensions or > > whatever they are in this case) are defacto reserved, because there are > > binaries (qemu in this) that have code acting on them out there. > > Numbers and things get marked reserved or the like > > > Anyway feel free to ignore since this might be different than drivers/gpu. > > AFAIK drives/gpu has a lot wider userspace, rdma manages this OK > because we only have one library package that provides the user/kernel > interface. But since we have some many projects we've started asking all the userspace projects to directly take the kernel ones (after the make step to filter them) so that there's only one source of truth. And also to make sure they don't merge stuff before the kernel side is reviewed&landed. Which also means we can't ditch anything userspace might still need on older trees and stuff. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch