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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ED1C2C43217 for ; Wed, 3 Nov 2021 16:20:00 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BA04760EB8 for ; Wed, 3 Nov 2021 16:20:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org BA04760EB8 Authentication-Results: mail.kernel.org; dmarc=pass (p=none dis=none) header.from=xenproject.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.221087.382611 (Exim 4.92) (envelope-from ) id 1miIzB-0000t9-Cv; Wed, 03 Nov 2021 16:19:37 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 221087.382611; Wed, 03 Nov 2021 16:19:37 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1miIzB-0000t2-9x; Wed, 03 Nov 2021 16:19:37 +0000 Received: by outflank-mailman (input) for mailman id 221087; Wed, 03 Nov 2021 16:19:36 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1miIz9-0000sw-UK for xen-devel@lists.xenproject.org; Wed, 03 Nov 2021 16:19:35 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1miIz9-0004my-Q2 for xen-devel@lists.xenproject.org; Wed, 03 Nov 2021 16:19:35 +0000 Received: from iwj (helo=mariner.uk.xensource.com) by xenbits.xenproject.org with local-bsmtp (Exim 4.92) (envelope-from ) id 1miIz9-0002rc-OP for xen-devel@lists.xenproject.org; Wed, 03 Nov 2021 16:19:35 +0000 Received: from iwj by mariner.uk.xensource.com with local (Exim 4.89) (envelope-from ) id 1miIz1-0004mp-7a; Wed, 03 Nov 2021 16:19:27 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xenproject.org; s=20200302mail; h=References:In-Reply-To:Subject:Cc:To:Date :Message-ID:Content-Transfer-Encoding:Content-Type:MIME-Version:From; bh=ab5CL6e3yOj6109hkJWHetVrsHpL7IULwpbRJx4AE/o=; b=JColMU4EnNms0dbHQHWoOAYfqg 6ks/K52Itn78Y8QbBN3zGDalZDQUwFPBoBZBJseYRdTp23PIayGwvELlrBlvbB0CVVioSFOUgLUMN CoBFsvl7QYzzigeyxH6trGm+L7sVvPzfYIyjFfnZV28+gemwJLlKljiZji7cUoygJGuU=; From: Ian Jackson MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <24962.46734.824520.805708@mariner.uk.xensource.com> Date: Wed, 3 Nov 2021 16:19:26 +0000 To: Jan Beulich Cc: Wei Liu , Roger Pau =?iso-8859-1?Q?Monn=E9?= , Paul Durrant , "xen-devel\@lists.xenproject.org" , Andrew Cooper Subject: Re: [PATCH v2 0/3][4.16] x86/IOMMU: enabled / intremap handling In-Reply-To: References: <09137aa2-649f-08fb-ba68-75f8eb16fc63@suse.com> X-Mailer: VM 8.2.0b under 24.5.1 (i686-pc-linux-gnu) Jan Beulich writes ("Re: [PATCH v2 0/3][4.16] x86/IOMMU: enabled / intremap handling"): > On 02.11.2021 11:17, Jan Beulich wrote: > > On 21.10.2021 11:57, Jan Beulich wrote: > >> In the course of reading the response to v1 (patch 1 only) I realized > >> that not only that patch needs further adjustment, but that also > >> further changes are needed (and there's likely yet more amiss). > >> > >> 1: x86/IOMMU: mark IOMMU / intremap not in use when ACPI tables are missing > >> 2: x86/APIC: avoid iommu_supports_x2apic() on error path > >> 3: AMD/IOMMU: iommu_enable vs iommu_intremap > > > > Ian, while we further discuss / refine patch 3, the first two have the > > needed R-b, but will now need you release-ack aiui. > > Seeing your reply on IRC, here an attempt at a release justification > (the patches were ready by Oct 29, but no-one cared to commit them > in my absence, so I thought I'd get away without such a write-up): > > Patch 1 addresses a regression identified by Andrew. The main risk I > see here (which has turned up only very recently) is disagreement on > patch 3 which imo has an effect also on what patch 1 does, as to the > (non-)effects of "iommu=off" on the hypervisor command line. This, > however, is not an effect of the patch, but pre-existing behavior. > The behavioral change (in this regard) is in patch 3, which is still > under discussion. Thank you. I also went to the list and read the thread there. Patch 1: Reviewed-by: Ian Jackson > Patch 2 corrects an (unlikely but not impossible to be taken) error > path, supposedly making systems functional again in case they would > in fact cause that error path to be taken. The risk looks low to me, > given that two function calls with previously assumed to be > identical results now get folded into one with the result latched. This one also: Release-Acked-by: Ian Jackson I think, from reading the thread, that patch 3 is not targeting 4.16. Thanks, Ian.