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 74E29C433DB for ; Mon, 4 Jan 2021 13:00:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3FD09207B1 for ; Mon, 4 Jan 2021 13:00:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725840AbhADNAR (ORCPT ); Mon, 4 Jan 2021 08:00:17 -0500 Received: from out3-smtp.messagingengine.com ([66.111.4.27]:44367 "EHLO out3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725830AbhADNAR (ORCPT ); Mon, 4 Jan 2021 08:00:17 -0500 Received: from compute6.internal (compute6.nyi.internal [10.202.2.46]) by mailout.nyi.internal (Postfix) with ESMTP id 0AA0E5C00F3; Mon, 4 Jan 2021 07:59:11 -0500 (EST) Received: from mailfrontend1 ([10.202.2.162]) by compute6.internal (MEProxy); Mon, 04 Jan 2021 07:59:11 -0500 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=fm2; bh=SGDnnCt0uFTHOCWQ0LWPQYmStfb uZROYTvcicN80T3A=; b=LWS7aA5Xw7GukcoE3nTpGKYpJ5EPifOCGqYGedCqNcE gb8EE7EjdVl9zJsceO3vr2FeVrJ4D6qqJ45qhmH3ZeI9g+MNzHml4i0T/W4tF2lX ufEzTzqHmeW9FIt39t9AFMHQ/xUOq6HqRzyP93z6egrFVPq7rwpJfvLQy2abGpnr Z4PxevNPCle0zZ9zLq4X2qJOavkdkK5Rej/JSGEnPiI+CBzO+kdE/EuZTJgb1u5q QrwrTsXE4O2G3JUC8yPp6im8ALIVH2c50e5qENP5r3oXzPBmSPKr2YoFkz3gxOlp xdLJUXVJQuk0M3GzglVXcGlQ3JAjUFBndBtbvu/5brw== 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=fm1; bh=SGDnnC t0uFTHOCWQ0LWPQYmStfbuZROYTvcicN80T3A=; b=JPdVZ8EBYnV+2Z+gNzLEEJ OZpNpliMIDozSzoPGWEbxa+xj3h3PXtBsRt6G3VmD00KgtKn+cwlXro2gKPKNieK OHTCxv6OXVMe4Io6MDUn+60RUta2zO/GlTyCs+ipEkKgE9P1rXchIQ/Ctlqn5lQH 7r+Sql10YLlk3zeP28QoopWay59cxEXBG/RqE1WOMr1Reaa5SwGTM8HfXjnIXTm1 4489CpHxSBxTIIOT9OowJ7RdEigAzeG/0fR9GTuCyP0R7TbCIz8l7XTXHM2pansw PqC6B9EHFwCKKxtWgACX72cVBNkrTOrz+VPu1jH8OaqKWDBrhfc2XFHNQ+9yvmzg == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedujedrvdeffedggeelucetufdoteggodetrfdotf 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 698C024005A; Mon, 4 Jan 2021 07:59:09 -0500 (EST) Date: Mon, 4 Jan 2021 14:00:36 +0100 From: Greg KH To: David Rientjes Cc: Peter Gonda , stable@vger.kernel.org, "Lendacky, Thomas" , "Singh, Brijesh" , Christoph Hellwig , nsaenzjulienne@suse.de, geert@linux-m68k.org, sjhuang@iluvatar.ai Subject: Re: [PATCH 00/30 for 5.4] Backport unencrypted non-blocking DMA allocations Message-ID: References: <20200925161916.204667-1-pgonda@google.com> <20201005130729.GD827657@kroah.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 Tue, Oct 06, 2020 at 11:10:41AM -0700, David Rientjes wrote: > Thanks Peter. > > The series of commits certainly expanded from my initial set that I asked > about in a thread with the subject "DMA API stable backports for AMD SEV" > on May 19. Turns out that switching how DMA memory is allocated based on > various characteristics of the allocation and device is trickier than > originally thought :) There were a number of fixes that were needed for > subtleties and cornercases that folks ran into, but were addressed and > have been merged by Linus. I believe it's stable in upstream and that > we've been thorough in compiling a full set of changes that are required > for 5.4. > > Note that without this series, all SEV-enabled guests will run into the > "sleeping function called from invalid context" issue in the vmalloc layer > that Peter cites when using certain drivers. For such configurations, > there is no way to avoid the "BUG" messages in the guest kernel when using > AMD SEV unless this series is merged into an LTS kernel that the distros > will then pick up. > > For my 13 patches in the 30 patch series, I fully stand by Peter's > backports and rationale for merge into 5.4 LTS. Given that this "feature" has never worked in the 5.4 or older kernels, why should this be backported there? This isn't a bugfix from what I can tell, is it? And if so, what kernel version did work properly? And if someone really wants this new feature, why can't they just use a newer kernel release? thanks, greg k-h