From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from zen.linaroharston ([85.9.250.243]) by smtp.gmail.com with ESMTPSA id n23-20020a7bc5d7000000b003ee74c25f12sm19634231wmk.35.2023.05.09.04.39.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 May 2023 04:39:30 -0700 (PDT) Received: from zen (localhost [127.0.0.1]) by zen.linaroharston (Postfix) with ESMTP id 288D41FFBB; Tue, 9 May 2023 12:39:30 +0100 (BST) References: <20230503091244.1450613-1-alex.bennee@linaro.org> <20230503091244.1450613-6-alex.bennee@linaro.org> <531a2eab-f0e6-46a5-c021-c82746c1ae38@redhat.com> <87y1m5s9yl.fsf@linaro.org> <5fb214d8-4a54-f896-f23f-fe9e646e4b2d@redhat.com> <878re4cl1u.fsf@suse.de> <70da6b28-d731-7e3b-b5a6-7d9983389d57@redhat.com> User-agent: mu4e 1.11.4; emacs 29.0.90 From: Alex =?utf-8?Q?Benn=C3=A9e?= To: Paolo Bonzini Cc: Peter Maydell , Fabiano Rosas , qemu-devel , Laurent Vivier , Artyom Tarasenko , "Edgar E. Iglesias" , Wainer dos Santos Moschetta , Thomas Huth , Leif Lindholm , Gerd Hoffmann , Helge Deller , Xiaojuan Yang , Stefan Hajnoczi , Cleber Rosa , Eduardo Habkost , Juan Quintela , John Snow , Yoshinori Sato , =?utf-8?Q?C=C3=A9dric?= Le Goater , Ilya Leoshkevich , Pavel Dovgalyuk , Andrew Jeffery , qemu-s390x , Richard Henderson , qemu-arm , Bastian Koppelmann , Beraldo Leal , Max Filippov , =?utf-8?Q?Marc-And?= =?utf-8?Q?r=C3=A9?= Lureau , Mark Cave-Ayland , Jiaxun Yang , Radoslaw Biernacki , Aurelien Jarno , David Hildenbrand , Markus Armbruster , Song Gao , Joel Stanley , =?utf-8?Q?Daniel_P=2E_Berrang=C3=A9?= , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Subject: Re: [PATCH 05/22] hw/arm: Select VIRTIO_NET for virt machine Date: Tue, 09 May 2023 12:37:15 +0100 In-reply-to: <70da6b28-d731-7e3b-b5a6-7d9983389d57@redhat.com> Message-ID: <878rdxbuoe.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-TUID: Pmt/mK7vZJO6 Paolo Bonzini writes: > On 5/9/23 12:00, Peter Maydell wrote: >> On Tue, 9 May 2023 at 10:42, Paolo Bonzini wrote: >>> >>> On 5/9/23 11:27, Peter Maydell wrote: >>>> On Mon, 8 May 2023 at 23:24, Paolo Bonzini wrote: >>>>> --without-default-devices is not about choosing to not build >>>>> some devices; it is about making non-selected devices opt-in >>>>> rather than opt-out. >>>> >>>> Hmm, so it's basically "the person doing the configuration needs >>>> to know what they're doing, the Kconfig system will give them >>>> no hints about what devices might or might not be needed to >>>> make machine type M functional" ? >>> >>> It depends on what you mean by functional. I would say you do get what >>> is needed to have a functional machine, but not what is needed to have a >>> useful machine. >> If you need to pass '-nodefaults' to get the thing to start up at >> all, that seems to be stretching the definition of "functional" >> to me. > > Then, an accurate description that uses "functional" in that sense > could be as follows: > > The Kconfig system will include any devices and subsystems that are > mandatory for a given machine type, and will flag any configuration > conflicts. However, the person doing the configuration still needs to > know which devices are needed (on top of the mandatory ones) to obtain > a functional guest, and Kconfig will not provide any hints in this > respect. So I thought that was the model I was following in adding devices but it seems I don't understand the no-defaults behaviour. What is the difference between a device that is added in the machine.c that makes it required or expendable with -nodefaults? > > Paolo --=20 Alex Benn=C3=A9e Virtualisation Tech Lead @ Linaro