From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-186.mta0.migadu.com (out-186.mta0.migadu.com [91.218.175.186]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E0F032BF00B for ; Wed, 12 Nov 2025 16:37:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.186 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762965445; cv=none; b=XC6XyhMNkZH9+F9ITpx98zXiug/2HBxTyfJluQ6S8eVUqUhqaFbpX07jlSP43rxrL39o/epb6oRYu2RXD4ZuV3jVirSk80SBWijiszALuw4j/gG4dqmoBAoNUFjLTKkcUsbsZJaNRryz/1fBxX1FbZmLuR5ityBhlO+u3iZThe0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762965445; c=relaxed/simple; bh=1DWc0mFPWuYlwrmYN4N/2p58Cj8JujiPs8naD1Ong/M=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=GwRpLxwIdRadKr2ATuomEj94yQIiNg7lqc0sTkN3HwJSRr5Cw7y6ql//vYisOXmuwlHBof6hUjksU0QKl87iwKPZFdoeuuCwgZiEPowPnu2zDa/3Us6OFmv8nsXSPuQgXOXlvXLpA6Rvmk4k5hg6VirGYZh8n9qVAvQlfCavBCI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=Wh0PCCqE; arc=none smtp.client-ip=91.218.175.186 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="Wh0PCCqE" 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: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 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