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 smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5033BC433FE for ; Fri, 4 Mar 2022 16:34:42 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id F01B760881; Fri, 4 Mar 2022 16:34:41 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 8bzlI-ZW9Xou; Fri, 4 Mar 2022 16:34:41 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp3.osuosl.org (Postfix) with ESMTPS id E5CA760810; Fri, 4 Mar 2022 16:34:40 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id BC280C0012; Fri, 4 Mar 2022 16:34:40 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 9A86CC000B for ; Fri, 4 Mar 2022 16:34:39 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 7400E60810 for ; Fri, 4 Mar 2022 16:34:39 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id GPJ9otjo_N_l for ; Fri, 4 Mar 2022 16:34:38 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by smtp3.osuosl.org (Postfix) with ESMTPS id 7C36F60758 for ; Fri, 4 Mar 2022 16:34:37 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id E2BFF68AFE; Fri, 4 Mar 2022 17:34:30 +0100 (CET) Date: Fri, 4 Mar 2022 17:34:30 +0100 From: Christoph Hellwig To: Stefano Stabellini Subject: Re: [PATCH 11/12] swiotlb: merge swiotlb-xen initialization into swiotlb Message-ID: <20220304163430.GA12317@lst.de> References: <20220301105311.885699-1-hch@lst.de> <20220301105311.885699-12-hch@lst.de> <20220302081500.GB23075@lst.de> <20220303105931.GA15137@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Cc: linux-hyperv@vger.kernel.org, x86@kernel.org, linux-ia64@vger.kernel.org, linux-pci@vger.kernel.org, linux-riscv@lists.infradead.org, Christoph Hellwig , linux-s390@vger.kernel.org, Konrad Rzeszutek Wilk , tboot-devel@lists.sourceforge.net, xen-devel@lists.xenproject.org, David Woodhouse , Tom Lendacky , Anshuman Khandual , Boris Ostrovsky , linux-arm-kernel@lists.infradead.org, Juergen Gross , Robin Murphy , linux-mips@vger.kernel.org, iommu@lists.linux-foundation.org, linuxppc-dev@lists.ozlabs.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Thu, Mar 03, 2022 at 02:49:29PM -0800, Stefano Stabellini wrote: > On Thu, 3 Mar 2022, Christoph Hellwig wrote: > > On Wed, Mar 02, 2022 at 05:25:10PM -0800, Stefano Stabellini wrote: > > > Thinking more about it we actually need to drop the xen_initial_domain() > > > check otherwise some cases won't be functional (Dom0 not 1:1 mapped, or > > > DomU 1:1 mapped). > > > > Hmm, but that would be the case even before this series, right? > > Before this series we only have the xen_swiotlb_detect() check in > xen_mm_init, we don't have a second xen_initial_domain() check. > > The issue is that this series is adding one more xen_initial_domain() > check in xen_mm_init. In current mainline xen_mm_init calls xen_swiotlb_init unconditionally. But xen_swiotlb_init then calls xen_swiotlb_fixup after allocating the memory, which in turn calls xen_create_contiguous_region. xen_create_contiguous_region fails with -EINVAL for the !xen_initial_domain() and thus caues xen_swiotlb_fixup and xen_swiotlb_init to unwind and return -EINVAL. So as far as I can tell there is no change in behavior, but maybe I'm missing something subtle? _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu