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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 588EDC0650F for ; Sun, 11 Aug 2019 05:56:15 +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 07853208C2 for ; Sun, 11 Aug 2019 05:56:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 07853208C2 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 C6E7FAC7; Sun, 11 Aug 2019 05:56:13 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 6AFF98B1; Sun, 11 Aug 2019 05:56:12 +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 BF70E6E0; Sun, 11 Aug 2019 05:56:11 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 0328568BFE; Sun, 11 Aug 2019 07:56:07 +0200 (CEST) Date: Sun, 11 Aug 2019 07:56:07 +0200 From: Christoph Hellwig To: Ram Pai Subject: Re: [RFC PATCH] virtio_ring: Use DMA API if guest memory is encrypted Message-ID: <20190811055607.GA12488@lst.de> References: <87zhrj8kcp.fsf@morokweng.localdomain> <20190810143038-mutt-send-email-mst@kernel.org> <20190810220702.GA5964@ram.ibm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190810220702.GA5964@ram.ibm.com> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: "Michael S. Tsirkin" , Benjamin Herrenschmidt , Jason Wang , Alexey Kardashevskiy , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Paul Mackerras , iommu@lists.linux-foundation.org, linuxppc-devel@lists.ozlabs.org, Christoph Hellwig , David Gibson 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 sev_active() is gone now in linux-next, at least as a global API. And once again this is entirely going in the wrong direction. The only way using the DMA API is going to work at all is if the device is ready for it. So we need a flag on the virtio device, exposed by the hypervisor (or hardware for hw virtio devices) that says: hey, I'm real, don't take a shortcut. And that means on power and s390 qemu will always have to set thos if you want to be ready for the ultravisor and co games. It's not like we haven't been through this a few times before, have we? _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu