Received: by 2002:ac0:a5a7:0:0:0:0:0 with SMTP id m36-v6csp2098252imm; Sat, 4 Aug 2018 19:22:36 -0700 (PDT) X-Google-Smtp-Source: AAOMgpej5rkvooiHUPeTHzLkpyIXqfk/TT5MbuM7S5kMTkdrB8L8QKwtqVYImVzJSK0u0o4CiCRr X-Received: by 2002:a62:43c8:: with SMTP id l69-v6mr11274610pfi.196.1533435756419; Sat, 04 Aug 2018 19:22:36 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1533435756; cv=none; d=google.com; s=arc-20160816; b=ffsAhwqp4j34Q8yIA9BauQxk1NCRB12FuihBZkE+ZWGJiBPPG53PYlCkYwxrnVrJfa iPZ8d0ct3qR3vbn+zZw3Un4R6PGgjRyIYxDdli7KeJLW/dlz1LwmV25uj05RK+TaNIVf AK0Bilh4LrSYfabOtXtcBD9OB+QWSo/XcKRIf4Wx7eS1QdI1vbjv3Y/z42GIPsbEbBlY sNbDF0M9RMaLdMVGs0CFPUfnsJq9Cd7TIoPaJ9XUg+RD8qmLS4NF+ZcgfdGXvyduzQZF SSBIAYvIvnuliNJM2F/typOi2PBAxdreQuMwKiu2UTnEO0tugz+mcZjwQckQ9b5AaTQV 4MAw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:date:cc:to:from:subject:message-id :arc-authentication-results; bh=+w5moHHpOWEpUFUbRwaEp7f/UifYYbO1RqLyxA+MpO0=; b=OUMHODD/Bjn3YlLWhkfkS/Ja/BoAeT0ko6TPDJ7hW4A2aLPJGNdyu44iYWiahjvcqJ Nh0r1CjzxOJ/m6uQGlHZS8kbZ7ByVnauyPIfuvwiSipR/+bAWOBhSdNStBSwzFFOhkgU O1ZHH1qraEv8vy6pGs5kH4YFpB/BxHrQ/qZa2XqJk7P+C4ntr9+rTk9YlXIS0kF3CxiU +ez37z+wOn6t8SfDvY/8N/8rsKnrTnPGQRcaf2ANCN2lnHLufDqjoe3X6lCyAbywTo5C Z0Zz2Qdu80FTpUYfTPME+hc2IzjjNcez0IgERiuvOgxpDouRJzLVxcF1OYPMHCkgmvub N+kQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id p3-v6si6634273pld.329.2018.08.04.19.22.20; Sat, 04 Aug 2018 19:22:36 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726138AbeHEEYR (ORCPT + 99 others); Sun, 5 Aug 2018 00:24:17 -0400 Received: from gate.crashing.org ([63.228.1.57]:35350 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725839AbeHEEYR (ORCPT ); Sun, 5 Aug 2018 00:24:17 -0400 Received: from localhost (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id w751BmJF004306; Sat, 4 Aug 2018 20:11:59 -0500 Message-ID: <76fdb044011f501834010694e79c369226bf0503.camel@kernel.crashing.org> Subject: Re: [RFC 0/4] Virtio uses DMA API for all devices From: Benjamin Herrenschmidt To: "Michael S. Tsirkin" , Christoph Hellwig Cc: Will Deacon , Anshuman Khandual , virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, aik@ozlabs.ru, robh@kernel.org, joe@perches.com, elfring@users.sourceforge.net, david@gibson.dropbear.id.au, jasowang@redhat.com, mpe@ellerman.id.au, linuxram@us.ibm.com, haren@linux.vnet.ibm.com, paulus@samba.org, srikar@linux.vnet.ibm.com, robin.murphy@arm.com, jean-philippe.brucker@arm.com, marc.zyngier@arm.com Date: Sun, 05 Aug 2018 11:11:32 +1000 In-Reply-To: <20180805030326-mutt-send-email-mst@kernel.org> References: <26c1d3d50d8e081eed44fe9940fbefed34598cbd.camel@kernel.crashing.org> <20180802182959-mutt-send-email-mst@kernel.org> <82ccef6ec3d95ee43f3990a4a2d0aea87eb45e89.camel@kernel.crashing.org> <20180802200646-mutt-send-email-mst@kernel.org> <20180802225738-mutt-send-email-mst@kernel.org> <20180803070507.GA1344@infradead.org> <20180803221634-mutt-send-email-mst@kernel.org> <20180804081500.GA1455@infradead.org> <20180805030326-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.4 (3.28.4-1.fc28) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2018-08-05 at 03:09 +0300, Michael S. Tsirkin wrote: > It seems that the fact that within guest it's implemented using a bounce > buffer and that it's easiest to do by switching virtio to use the DMA API > isn't something virtio spec concerns itself with. Right, this is my reasoning as well. See this other (long) email I just sent to Christoph to explain the whole flow. > I'm open to suggestions. Cheers, Ben.