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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EA057CD13DD for ; Wed, 12 Nov 2025 16:37:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=IuZkk1ecQ1y2YiIg61ZBzcctWSlR8+0B252L7V3ihsM=; b=c031XOdNxeiyKxdHi6byIKb8ca ycCah5KwO9FLvI5u3KKvO8PGlabIajXKm/OhPd5NXKmPrcj8g+L1pns5SF+VNtTQ2Lo3FuzNmLLCU ZwNKnepsB6Ldn6Gmn0ARnOFZYgq3kfnXKwQCxgS2CMjl9SgdXR90snUibyiU3R7ErvAJ8ilbvb+4W /M/+MXIRDjnZim+0ePm/C4BdKRmGNc7UNiI1/jxr0A5vkegHKXkSzYIN9fRUXdXZ8gMqM19bLg9Cp gb1stFsTMAEltllSCZ349dh5uJls861/z3UoFdkGxwPHghhzgvlxseXGOze3yquKrtw7Q3EK3VECK x+mcR64g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vJDqq-00000009Bwz-2I7t; Wed, 12 Nov 2025 16:37:44 +0000 Received: from out-170.mta0.migadu.com ([2001:41d0:1004:224b::aa]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vJDqn-00000009Buv-2oF6 for linux-um@lists.infradead.org; Wed, 12 Nov 2025 16:37:43 +0000 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1762965441; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=IuZkk1ecQ1y2YiIg61ZBzcctWSlR8+0B252L7V3ihsM=; b=Wh0PCCqE3a6g2qnRUMXZ1g3BIMxO6mZ6y7v4sB2g+UnJbZBfkGUQ7BmVF9gblYKJEFO0LK dkimfm3eG5fmJkuCNVSDL6U/VcZGlbifE4w5cwBp7d9r1g3Oa8628++g3z/VT9AgZtP6Hv ZuhetIod+UxQ7KziDDdDSBYYdCb7ncg= From: Tiwei Bie To: thehajime@gmail.com Cc: Liam.Howlett@oracle.com, hch@infradead.org, johannes@sipsolutions.net, linux-kernel@vger.kernel.org, linux-um@lists.infradead.org, ricarkol@google.com, tiwei.bie@linux.dev Subject: Re: [PATCH v13 00/13] nommu UML Date: Thu, 13 Nov 2025 00:36:51 +0800 Message-Id: <20251112163651.3689244-1-tiwei.bie@linux.dev> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251112_083741_922108_40BC8B5D X-CRM114-Status: GOOD ( 12.86 ) X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org On Wed, 12 Nov 2025 17:52:56 +0900, Hajime Tazaki wrote: [...] > > However, I'm not yet convinced that all of the complexities presented in > > this patchset (such as completely separate seccomp implementation) are > > actually necessary in support of _just_ the second bullet. These seem to > > me like design choices necessary to support the _first_ bullet [1]. > > separate seccomp implementation is indeed needed due to the design > choice we made, to use a single process to host a (um) userspace. I > think there is no reason to unify the seccomp part because the > signal handlers and filter installation do the different jobs. > > I don't see why you see this as a _complexity_, as functionally both > seccomp handling don't interfere each other. we have prepared > separate sub-directories for nommu to avoid unnecessary if/else > clauses in .c/.h files. I have the same concern about the complexities introduced by this patch set. The new processing paths it introduces (such as the separate handling for FP/SSE/AVX, FS, signal, syscall, ...) add a lot of unnecessary complexities. I think Johannes's suggestion is a great idea. > we haven't seen any functional regressions > since this RFC version (which was 6.12 kernel). I took a quick look at the code. It appears that patch 02/13 will break the mmu build when UML_TIME_TRAVEL_SUPPORT is enabled. Regards, Tiwei