From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794474588; b=RuFrCsE7wgE+RdPiZo5rmGKblUNCzO4obtHuHkRScyP3sQrEaVN6sp57MCewJrVufH1U 6NwOQgBtqCZFYy12G5MnjGhovSToUDuYqBdHuymRtKO7zbqN2shO2JrpnKNUbCSH51Otr T37DeKIIaZA0Eq5oZvU2SskW7xsBsY9qbYKQvhhPHHdBK+1gkB2t80j9OkgBrmVvYlV1r w6Bv8YCcxyS4k/J06GJR4mZUCwRdjod/3/3JaPqvfE03c+3G/yz94kyzNPTtdh1ym6Scq bcF/OYokCvBCj9js6+TARfATVv/o68JALspf154iU01ozXc911lBwc7Nldh61ViW7VA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794474588; h=Received:DKIM-Signature:Message-ID:Date:MIME-Version:User-Agent: Subject:To:Cc:References:From:Content-Language:Autocrypt:In-Reply-To: Content-Type:Content-Transfer-Encoding; bh=j/okRcwCmJah376/pTXlDGHeTd3yv114IA7qsrwTRhM=; b=JeO9NJIRzLWV/3fywxCgr3jv2YXP8m5lBny3wdKRxZBGoB/++ETN51TxrVoFbj8yDLSK rmhIF7aTY4mglPydjRKfPfEDtvpzTaYIXv6aQ9sZoT4Ctt8eSIefv9p6nY0zIoU7EyHUZ 3I6l5xnwNQUwayRgh6kE1GPtfv9DxRtetQ9gZXIzprEBuZ3R8WAVrHUXVE2nEVkUWHDln cIgMxoe/cJwAlvwutOMKnIrZZHmTTI/qDMtzm77mfl4Wc/1g2APwQ3NksdUyxaPRFytDv muFewGbHKIq5XSOOSbkFXdT1b6Oqkbw4Wr9M8PtWXTOZoyH4OrgrvR4Yzz09IHmo16g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=eHxjzh9f; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B96D9606A31C; Thu, 12 Nov 2026 09:09:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=eHxjzh9f Received: by smtp.kernel.org (Postfix) with ESMTPSA id 307DE1F00A05; Thu, 12 Nov 2026 09:09:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794474588; bh=j/okRcwCmJah376/pTXlDGHeTd3yv114IA7qsrwTRhM=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=eHxjzh9fX6/euYdOb/lVF0eGeyRB12MW7G+QY46JREN7vpgh9olDCgsYLX/pAzEQX IGV5dxMZ7b0c/DriZU6Eme05voULqlWWyL3IXZnyQuLunihl0MdTtGN8aeINL0bNWG Vm79nqp0mr4XhYQNoFSuzkSP/JNGzToHNTIe1C4Q8AqHz6YasMr9/u7NXCsOdcxrmr qlsPUcih2RuGYOTdpHqFhif7yvJqhVUn10NeLQxRNQA1wgBo2pXA0iV8g9cNF8it3I BAI5M6gxZVmyY0MT0oebPTr+QHkn1U6hPQGcF4Fxua1lNp6LLOh76Ogg8tgrazzQuo l0nwe7VmuIDqw== Message-ID: <32ad880e-5946-4703-9c6f-43ff59da39af@kernel.org> Date: Thu, 12 Nov 2026 10:09:37 +0100 X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/4] virtio_console: copy pipe buffers in splice_write() To: Arnd Bergmann , Linus Torvalds , Christian Brauner Cc: Matthew Wilcox , "Kirill A. Shutemov" , Alexander Viro , Miklos Szeredi , Amit Shah , Jan Kara , Zi Yan , Bernd Schubert , Hugh Dickins , Baolin Wang , Andrew Morton , Greg Kroah-Hartman , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , linux-fsdevel@vger.kernel.org, fuse-devel@lists.linux.dev, virtualization@lists.linux.dev, Netdev , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, Malin Jonsson , Richard Weinberger , Geert Uytterhoeven , Nishanth Menon , Frank Li References: <20261110145241.536019-1-kas@kernel.org> <20261110145241.536019-2-kas@kernel.org> <20261111-heimreisen-ungeziefer-empfunden-a892571f2c07@brauner> <20261111-thunfisch-wirbt-waldrand-822275b2d3b1@brauner> <20261111-stumpf-montag-miterleben-c4e2feac8090@brauner> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/12/26 09:55, Arnd Bergmann wrote: > On Wed, Nov 11, 2026, at 20:26, Linus Torvalds wrote: >> On Wed, 11 Nov 2026 at 10:53, Christian Brauner wrote: >>> >>> If that's the official new stance than I'm very happy. >> >> I definitely want to remove HIGHMEM entirely in the not too distant >> future. And before we remove it, we can most definitely document the >> fact that we will not be worried about insane users. >> >> And things like security issues count as "insane user": if you use >> HIGHMEM outside of controlled embedded setups or museum pieces you get >> to keep both pieces when it breaks. >> >> IOW, it's legacy. We should aim to not introduce *new* bugs to it, but >> if there are pre-existing bugs they very much count as "don't care", >> this will be removed soon. > > Agreed. There is also the option of adding Kconfig dependencies to > mark things that are known broken with highmem when we either know > that it is buggy, or we have a good reason to break something that > none of those remaining users should be using. > >> I think the only reason it wasn't removed a couple of years ago >> already is basically a few old 32-bit ARM platforms that still used >> it. >> >> Those platforms still exist, and I predict that they'll still exist >> next year, but if those users have to stay at the current LTS kernel, >> that's fine. > > I tried to push for what I thought was an aggressive timeline > last year, but that would still keep the Arm bits for a couple more > LTS releases and only gradually reduce the scope of highmem in the > meantime, removing support from architectures, file systems, and > drivers where possible. See https://lwn.net/Articles/1051010/ > for a summary of my talk in Tokyo, including the slides and > a link to the video for anyone wanting more details. > > I also prepared a number of patches towards this, but have so > far not been great at following up to get them merged, sorry > about that. I think we can already start at removing CONFIG_HIGHPTE now, right? -- Cheers, David