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AJvYcCUJQCQTeJwMxs+DCaqseXZF2s3He6DZP9BtQsqhnVsCV1f6T7Rf2iVwikaJhkMvo2q90tC9Juf8iw==@kvack.org X-Gm-Message-State: AOJu0YzA1HVdYz1dufObSwH/yIxkoJAIpuoJo623SP0a9hjjjcYHBAX/ XhqCMdm1ntD0Y3taPS2nxev+Qz5Vj0pJCEAICNvMzILM3Is1BtJuep9P1IE/hdGwO/8cIDDrWA5 tS7yZ9Fjj4SBgvSlRkj9UamMUR6R9kNM= X-Gm-Gg: ASbGncs9jJ5iA7YZevxkMHZhNkBl3RjDorjGdpIACNeMT0+GsewKHn50Q6kLkDsXRJs Ko3Ngl7wo+N7LumgZU0LX4wRbkH8+F2HyjB/qUJIHcKnnWeSaGYw1e3guC1ZLVb0+Dzv3Qjfyay i13sYCuD7m+ckKa5osnid/CCdOh3ATHfJOlBdfzEdn3fYtCJnZrJJs8+Li3ijQ6lIsvDRJjG9AC tdU3+cBPeZpcvOHpw+6q77abJNExxmii34YpTXv X-Google-Smtp-Source: AGHT+IGYQ8cZXq6p06Ik0TDBdufn7B3v54OBWxKvQ9AFYTgNeyye8BPJ3qw2CKkk7AUAcaDd0Kb3KEG7ImktB5zLhBw= X-Received: by 2002:a05:6102:2924:b0:52d:1b06:5e34 with SMTP id ada2fe7eead31-5b2826795b7mr3196814137.10.1759005815440; Sat, 27 Sep 2025 13:43:35 -0700 (PDT) MIME-Version: 1.0 References: <20250918222607.186488-1-xiyou.wangcong@gmail.com> <78127855-104f-46e2-e5d2-52c622243b08@gentwo.org> In-Reply-To: From: Cong Wang Date: Sat, 27 Sep 2025 13:43:23 -0700 X-Gm-Features: AS18NWBZ4NYpS8oIgxtkL6K4jFZHcC-C1DNvJN4aikZTVbjqp7kQjMuXYe8nY8M Message-ID: Subject: Re: [RFC Patch 0/7] kernel: Introduce multikernel architecture support To: Jarkko Sakkinen Cc: "Christoph Lameter (Ampere)" , linux-kernel@vger.kernel.org, pasha.tatashin@soleen.com, Cong Wang , Andrew Morton , Baoquan He , Alexander Graf , Mike Rapoport , Changyuan Lyu , kexec@lists.infradead.org, linux-mm@kvack.org, multikernel@lists.linux.dev Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 8CFF0C0004 X-Stat-Signature: s6juxqwsj456woqaqazhhmt7bd8r5fbr X-Rspam-User: X-HE-Tag: 1759005816-670407 X-HE-Meta: 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 GqKM6vNK 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Sep 26, 2025 at 2:50=E2=80=AFAM Jarkko Sakkinen = wrote: > > On Wed, Sep 24, 2025 at 11:39:44AM -0700, Cong Wang wrote: > > On Wed, Sep 24, 2025 at 10:51=E2=80=AFAM Christoph Lameter (Ampere) > > wrote: > > > AFAICT various contemporary Android deployments do the multiple kerne= l > > > approach in one way or another already for security purposes and for > > > specialized controllers. However, the multi kernel approaches are oft= en > > > depending on specialized and dedicated hardware. It may be difficult = to > > > support with a generic approach developed here. > > > > You are right, the multikernel concept is indeed pretty old, the Barrel= Fish > > OS was invented in around 2009. Jailhouse was released 12 years ago. > > There are tons of papers in this area too. > > Jailhouse is quite nice actually. Perhaps you should pick that up > instead, and start refining and improving it? I'd be interested to test > refined jailhouse patches. It's also easy build test images having the > feature both with BuildRoot and Yocto. Static partitioning is not a bad choice, except it is less flexible. We can= 't get dynamic resource allocation with just static partitioning, but we can easily get static partitioning with dynamic allocation, in fact, it should = be the default case. In my own opinion, the reason why containers today are more popular than VM's is not just performance, it is elasticity too. Static partitionin= g is essentially against elasticity. More fundamentally, it is based on VMCS, which essentially requires a hypervisor: https://github.com/siemens/jailhouse/blob/master/hypervisor/control.c > > It would take me like half'ish day to create build target for it. > > > Dual-kernel systems, whether using virtualization or firmware, are inde= ed > > common at least for automotives today. This is a solid justification of= its > > usefulness and real-world practice. > > OK so neither virtualization nor firmware are well defined here. > Firmware e.g. can mean anything fro pre-bootloader to full operating > system depending on context or who you ask. > > It's also pretty hard to project why VMs are bad for cars, and > despite lacking experience with building operating systems for > cars, I'd like to believe that the hardware enforcement that VT-x > and VT-d type of technologies bring is actually great for cars. > > It's like every other infosec con where someone is hacking a car, > and I seen even people who've participated to hackatons by car > manufacturers. That industry is improving gradually and the > challenge would be to create hard evidence that this brings > better isolation than VM based solutions.. In case it is still not clear: No one wants to stop you from using a VM. In fact, at least in theory, you could use a VM inside a multikernel. Just like today we can still run a container in a VM (Kata Container). Your choice is always on the table. I hope this helps. Regards, Cong Wang