From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40053) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gKj1d-000308-Kk for qemu-devel@nongnu.org; Thu, 08 Nov 2018 07:03:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gKj1Y-0006jb-HT for qemu-devel@nongnu.org; Thu, 08 Nov 2018 07:03:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:59526) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gKj1Y-0006j5-7w for qemu-devel@nongnu.org; Thu, 08 Nov 2018 07:03:00 -0500 References: <20180924092120.GA30163@caravaggio> <7c2b477e-bdac-c887-2510-82fe04acdcfe@redhat.com> <87b22690-e39c-3b46-dcb4-f6abc3213142@redhat.com> <41ceda53-467e-32a1-8fa6-13f0f9c08ad1@redhat.com> <20181107154114.GC27585@caravaggio> <20181107192414.GH12503@habkost.net> <28af4bea-e017-cdab-e5e4-a9809cb2e409@redhat.com> From: Paolo Bonzini Message-ID: <15d0b50a-6374-d520-e85c-2e73833a046c@redhat.com> Date: Thu, 8 Nov 2018 13:02:54 +0100 MIME-Version: 1.0 In-Reply-To: <28af4bea-e017-cdab-e5e4-a9809cb2e409@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] QEMU and Kconfig List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth , Eduardo Habkost Cc: Samuel Ortiz , "Zhong, Yang" , Peter Maydell , QEMU Developers On 08/11/2018 11:14, Thomas Huth wrote: > On 2018-11-08 10:55, Paolo Bonzini wrote: >> On 07/11/2018 20:30, Thomas Huth wrote: >>> On 2018-11-07 20:24, Eduardo Habkost wrote: >>>> On Wed, Nov 07, 2018 at 06:39:54PM +0100, Paolo Bonzini wrote: >>>>> On 07/11/2018 16:41, Samuel Ortiz wrote: >>>>>> - The Kconfig parser would be used to generate the equivalent of w= hat we >>>>>> currently have under default-configs/ >>> >>> I think we would still have something like default-configs - but ther= e >>> would only be the bare minimum config switches in there, the rest wou= ld >>> be pulled in by dependencies. >> >> Yes, in theory default-configs would end up empty, except for possibly >> some commented lines to show the "default y" symbols for the target. >=20 > I think we should enable the machines in the default configs (and maybe > optional devices that are not automatically selected by machines), e.g.= : >=20 > CONFIG_I440FX=3Dy > CONFIG_Q35=3Dy > CONFIG_VIRTPC=3Dy > CONFIG_ISAPC=3Dy > CONFIG_VIRTIO=3Dy > CONFIG_PARALLEL=3Dy >=20 > In configs/nemu (or configs/lean-kvm or however we'll call it), you wil= l > then only have: >=20 > CONFIG_Q35=3Dy > CONFIG_VIRTPC=3Dy > CONFIG_VIRTIO=3Dy >=20 > Would that make sense? It would, however it would be hard to draw a line between which devices are enabled by default or not. I think in particular all devices that currently are in default-configs/{hyperv,pci,sound,usb,virtio}.mak should be "default y". CONFIG_PARALLEL would be in a hypothetical isa.mak and also "default y". One example that we discussed of devices that should not be "default y" is stuff like various I2C sensors (CONFIG_TMP105 for example); these should not be included in x86 targets just because x86 has an I2C/SMBus controller in it. So for example tmp105 should probably be select-ed by CONFIG_ASPEED and CONFIG_NSERIES. Let me reiterate that your proposal _also_ makes sense, in fact it's exactly it is done in the 2015 branch. However, if everything were "default y" and we write a script to write out the selected configuration symbols to default-configs/ file, the difference would be mostly that the lines in default-configs/ will look like "#CONFIG_I440FX=3Dy" instead of "CONFIG_I440FX=3Dy". And in fact, the latter would be nicer for people who want to modify default-configs/ to specify a few boards and devices explicitly[1]. For such people (which include both the RHEL QEMU and the NEMU maintainers) after a rebase you would not get any new board or device. So I'm inclined more towards empty default-configs/ file, with comments mentioning what can be enabled. Paolo