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([2001:b07:6468:f312:784d:f09c:63f4:b9cb]) by smtp.gmail.com with ESMTPSA id a184sm10620444wmf.29.2020.01.25.03.55.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 25 Jan 2020 03:55:50 -0800 (PST) Subject: Re: Making QEMU easier for management tools and applications To: =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= , Markus Armbruster References: <87h81unja8.fsf@dusky.pond.sub.org> <20191224134139.GD2710539@redhat.com> From: Paolo Bonzini Message-ID: <0c5f198f-9be5-8ba4-41bf-29e41b99c9c5@redhat.com> Date: Sat, 25 Jan 2020 12:55:50 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20191224134139.GD2710539@redhat.com> Content-Language: en-US X-MC-Unique: -o2hY0xtOs2jC7fEc9vfNw-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 207.211.31.81 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Peter Maydell , "Denis V. Lunev" , Cleber Rosa , Stefan Hajnoczi , qemu-devel , =?UTF-8?Q?Marc-Andr=c3=a9_Lureau?= , Dominik Csapak , John Snow , Eduardo Habkost Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 24/12/19 14:41, Daniel P. Berrang=C3=A9 wrote: > I'm wondering if we need to think about a temporary *throwaway* fork of > QEMU. I wasn't involved in the work, but as an outside observer I think > it is interesting to see how the NEMU project fork ultimately led to QEMU > moving forward with a new KConfig approach, and the integration of microv= m. > They had the freedom to develop these new approaches with zero regard > to back compat or broader QEMU needs that might otherwise hold back dev. Just a quick note: none of these were developed first in NEMU. KConfig was completed *for* NEMU (to make their lives easier) but the code already existed, and microvm is inspired by Firecracker. NEMU's main merit in my opinion was to make QEMU's perception issues clearer, and to cause more thought on those issues and how to approach it. That said, I agree that a throwaway experiment on command line and configuration is worthwhile. The main thing to think about is to make convenience options syntactic sugar for something else. For example, a couple ideas mentioned in the thread or elsewhere in hallway discussions: - Make default devices expressible as QemuOpts, so that -writeconfig able to write out the default devices as well and -readconfig would imply -nodefaults. - Reduce the scope of -drive by dropping if=3Dnone in favor of -blockdev. Leave -drive as a quick way of configuring frontend and backend. - And somewhat unrelated to configuration files: generate bindings for QMP clients from the schema. In the meanwhile, we should deprecate -readconfig/-writeconfig. Can't go wrong with that. Paolo