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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A5A02CAC5A7 for ; Sun, 21 Sep 2025 05:54:38 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 02FAA8E000A; Sun, 21 Sep 2025 01:54:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F20BD8E0001; Sun, 21 Sep 2025 01:54:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E36E68E000A; Sun, 21 Sep 2025 01:54:37 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id D1EEE8E0001 for ; Sun, 21 Sep 2025 01:54:37 -0400 (EDT) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 7B9BFB7FA0 for ; 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t=1758434076; a=rsa-sha256; cv=none; b=xlQBmRNHPz+OtmXYzqAKUvBX/d4Jte8sQTzLehIjYukN5A8a4J/Z7B0+XbWQxVtKZxfHlr bOvpsd6XN4bKo5heMGgP88LNl14cbLZyo24e1Q3w2hW6NV+YZTr92jfM0wjPk+4mvYnKKY iG40PwpIcwWy+lBCAzvf50J5CZIeg+s= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=none; spf=pass (imf12.hostedemail.com: domain of ej@inai.de designates 144.76.212.145 as permitted sender) smtp.mailfrom=ej@inai.de; dmarc=none Received: by a3.inai.de (Postfix, from userid 25121) id AF8151003C5102; Sun, 21 Sep 2025 07:54:31 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by a3.inai.de (Postfix) with ESMTP id ADE391100A8ED8; Sun, 21 Sep 2025 07:54:31 +0200 (CEST) Date: Sun, 21 Sep 2025 07:54:31 +0200 (CEST) From: Jan Engelhardt To: Cong Wang cc: 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 Subject: Re: [RFC Patch 0/7] kernel: Introduce multikernel architecture support In-Reply-To: <20250918222607.186488-1-xiyou.wangcong@gmail.com> Message-ID: <3ns36rp5-rp37-1nns-9q43-op05or6s26nq@vanv.qr> References: <20250918222607.186488-1-xiyou.wangcong@gmail.com> User-Agent: Alpine 2.26 (LSU 649 2022-06-02) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Stat-Signature: dbh68s8tn96opd48apwbucffqoo3ugcs X-Rspamd-Queue-Id: 8140F40004 X-Rspam-User: X-Rspamd-Server: rspam03 X-HE-Tag: 1758434075-828061 X-HE-Meta: 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 GMSzPcjV /oLTOnYfMNz5gkmpwckF4Evfs+UzeJ6HOfMWfaTtKSzcEcaohyZtNjhsnw2q7PCLEMxlpFgaEAE3gzSUBjeg5hRLWoRRWoU+zdPOMb4aYIe/dWzD3BJjueELB+8FbZx/P8A8e 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 Friday 2025-09-19 00:25, Cong Wang wrote: >This patch series introduces multikernel architecture support, enabling >multiple independent kernel instances to coexist and communicate on a >single physical machine. > >Each kernel instance can run on dedicated CPU >cores while sharing the underlying hardware resources. I initially read it in such a way that that kernels run without supervisor, and thus necessarily cooperatively, on a system. But then I looked at , saw that there is a kernel on top of a kernel, to which my reactive thought was: "well, that has been done before", e.g. User Mode Linux. While UML does not technically talk to hardware directly, continuing the thought "what's stopping a willing developer from giving /dev/mem to the subordinate kernel". On second thought, a hypervisor is just some kind of "miniature kernel" too (if generalizing very hard).