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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 F2040C10F14 for ; Tue, 15 Oct 2019 07:35:09 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (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 CD75D2086A for ; Tue, 15 Oct 2019 07:35:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CD75D2086A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 99A28B79; Tue, 15 Oct 2019 07:35:09 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 8157DB6D; Tue, 15 Oct 2019 07:35:08 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 1423D5D3; Tue, 15 Oct 2019 07:35:08 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 4C96D68CEE; Tue, 15 Oct 2019 09:35:02 +0200 (CEST) Date: Tue, 15 Oct 2019 09:35:01 +0200 From: Christoph Hellwig To: Ram Pai Subject: Re: [PATCH 2/2] virtio_ring: Use DMA API if memory is encrypted Message-ID: <20191015073501.GA32345@lst.de> References: <1570843519-8696-1-git-send-email-linuxram@us.ibm.com> <1570843519-8696-2-git-send-email-linuxram@us.ibm.com> <1570843519-8696-3-git-send-email-linuxram@us.ibm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1570843519-8696-3-git-send-email-linuxram@us.ibm.com> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: andmike@us.ibm.com, sukadev@linux.vnet.ibm.com, mdroth@linux.vnet.ibm.com, b.zolnierkie@samsung.com, benh@kernel.crashing.org, jasowang@redhat.com, aik@linux.ibm.com, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, paulus@ozlabs.org, iommu@lists.linux-foundation.org, paul.burton@mips.com, mpe@ellerman.id.au, robin.murphy@arm.com, linuxppc-dev@lists.ozlabs.org, hch@lst.de, david@gibson.dropbear.id.au X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 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 Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org On Fri, Oct 11, 2019 at 06:25:19PM -0700, Ram Pai wrote: > From: Thiago Jung Bauermann > > Normally, virtio enables DMA API with VIRTIO_F_IOMMU_PLATFORM, which must > be set by both device and guest driver. However, as a hack, when DMA API > returns physical addresses, guest driver can use the DMA API; even though > device does not set VIRTIO_F_IOMMU_PLATFORM and just uses physical > addresses. Sorry, but this is a complete bullshit hack. Driver must always use the DMA API if they do DMA, and if virtio devices use physical addresses that needs to be returned through the platform firmware interfaces for the dma setup. If you don't do that yet (which based on previous informations you don't), you need to fix it, and we can then quirk old implementations that already are out in the field. In other words: we finally need to fix that virtio mess and not pile hacks on top of hacks. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu