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 X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB198C433B4 for ; Sat, 24 Apr 2021 14:43:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AE3B06144D for ; Sat, 24 Apr 2021 14:43:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232035AbhDXOo3 (ORCPT ); Sat, 24 Apr 2021 10:44:29 -0400 Received: from out3-smtp.messagingengine.com ([66.111.4.27]:46047 "EHLO out3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229630AbhDXOo3 (ORCPT ); Sat, 24 Apr 2021 10:44:29 -0400 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailout.nyi.internal (Postfix) with ESMTP id 6938E5C00D9; Sat, 24 Apr 2021 10:43:50 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute4.internal (MEProxy); Sat, 24 Apr 2021 10:43:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kroah.com; h= date:from:to:cc:subject:message-id:references:mime-version :content-type:in-reply-to; s=fm3; bh=2ZOfQhPJ+uxZJ5RC6Fp4DFPdIwM NdnjI00W7BuBOvhY=; b=q2rhkY/1dpcs6KVp70ra4MSSQ9UOliYIj25vws7jA1X z9Nm0iLUErzCrSOyDjTO9NzBhHpthDDhvSrAhtcJE0Hfl6MrMZAlvlBDyAZJu7IQ K90abSilsO4DuOxNryh1kRQV7SXiy6o5WJlQPVcIBJnb8DsKfZyYv1eXQS3zgAr6 lQw67NFUgeMz/zbCNvvJpuPCdioNwXfgKZUGvTi57rYcWEnfHHAWPhNs8WEpkNe9 cDiwrRCVgsXVxx9obQ0/SsNdfFCenziwhIRXU4Jhx2HroeMfy8q8vxL5sPYAMvfk qeypaRODNcfHeyIXNzPPFGF4KncyLbae2/bbnBqvdeA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm2; bh=2ZOfQh PJ+uxZJ5RC6Fp4DFPdIwMNdnjI00W7BuBOvhY=; b=pgl0XA+Ts45SFG93UGp0K1 jszlUkS2jfx6Y9uxKdKDqrSSDESFmv1paP+YeVe7gsSCq1YlXTrkIbtV929rmF5u //MjGPXeSsduIbc0IWPtFbB7AcXUEAskSnPb+93GR8cJRfdeLqySTd8S6Wcisc7c AK1UGrK0b3hYbKAR3hcSgfnQFQfgdept9PukSlzF6Uyjrh/hS6pPHPRWm812ZTm5 Rlznql1XrVGc+DnD9H2UnQjMQ7AxqJRl0Jt83rgxpeNJtQOqRI42zHuKktoMShpl iF1iT2eIoTGB2UAslKB2DwW2H2i1yfvAr6qLq8ic4q9CHwEmShD1ecoMuUu/3eLA == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrvddugedgkeduucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepfffhvffukfhfgggtuggjsehttdertddttddvnecuhfhrohhmpefirhgvghcu mffjuceoghhrvghgsehkrhhorghhrdgtohhmqeenucggtffrrghtthgvrhhnpeevueehje fgfffgiedvudekvdektdelleelgefhleejieeugeegveeuuddukedvteenucfkphepkeef rdekiedrjeegrdeigeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrih hlfhhrohhmpehgrhgvgheskhhrohgrhhdrtghomh X-ME-Proxy: Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) by mail.messagingengine.com (Postfix) with ESMTPA id EB8C9108005B; Sat, 24 Apr 2021 10:43:49 -0400 (EDT) Date: Sat, 24 Apr 2021 16:43:48 +0200 From: Greg KH To: Jianxiong Gao Cc: stable@vger.kernel.org Subject: Re: [PATCH v5.10 0/8] preserve DMA offsets when using swiotlb Message-ID: References: <20210405210230.1707074-1-jxgao@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Fri, Apr 23, 2021 at 10:28:32AM -0700, Jianxiong Gao wrote: > > How? Anything that installed 5.10 when it was released never had this > > working, they had to move to 5.12 to get that to work. > > I wasn't clear. The bug is not specific to SEV virtualization. We > simply encountered it while working on SEV virtualization. This is a > pre-existing bug. > > Briefly, the NVMe spec expects a page offset to be retained from the > memory address space to the IO address space. > > Before these patches, the SWIOTLB truncates any page offset. > > Thus, all NVMe + SWIOTLB systems are broken due to this bug without > these patches. Ok, and what prevents you from adding this new feature do your "custom" kernel, or to use 5.12 instead? This is a new feature that Linux has never supported, and these patches are not "trivial" at all. I also do not see the maintainer of the subsystem agreeing that these are needed to be backported, which is not a good sign. So I recommend just using a newer kernel version, that way all will be good and no need to backport anything. What is preventing you from doing that today? thanks, greg k-h