Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754263AbcDSRam (ORCPT ); Tue, 19 Apr 2016 13:30:42 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:55538 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752924AbcDSRal (ORCPT ); Tue, 19 Apr 2016 13:30:41 -0400 Message-ID: <1461083204.20056.8.camel@infradead.org> Subject: Re: [PATCH RFC] fixup! virtio: convert to use DMA api From: David Woodhouse To: "Michael S. Tsirkin" , Andy Lutomirski Cc: "qemu-devel@nongnu.org Developers" , "linux-kernel@vger.kernel.org" , Paolo Bonzini , peterx@redhat.com, Cornelia Huck , Stefan Hajnoczi , Kevin Wolf , Amit Shah , qemu-block@nongnu.org, Jason Wang , Alex Williamson , Andy Lutomirski , Christian Borntraeger , Wei Liu , Linux Virtualization , kvm list In-Reply-To: <20160419191914-mutt-send-email-mst@redhat.com> References: <1460992923.3765.8.camel@infradead.org> <20160418182320-mutt-send-email-mst@redhat.com> <1460994701.3765.23.camel@infradead.org> <20160418190203-mutt-send-email-mst@redhat.com> <1461004173.3765.73.camel@infradead.org> <20160419130732-mutt-send-email-mst@redhat.com> <20160419190520-mutt-send-email-mst@redhat.com> <20160419191914-mutt-send-email-mst@redhat.com> Content-Type: multipart/signed; micalg="sha-1"; protocol="application/x-pkcs7-signature"; boundary="=-ru4Xo2uWpX8E5ZFs+Rvl" Date: Tue, 19 Apr 2016 12:26:44 -0400 Mime-Version: 1.0 X-Mailer: Evolution 3.18.5.2 (3.18.5.2-1.fc23) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8598 Lines: 131 --=-ru4Xo2uWpX8E5ZFs+Rvl Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2016-04-19 at 19:20 +0300, Michael S. Tsirkin wrote: >=20 > > I thought that PLATFORM served that purpose.=C2=A0 Woudn't the host > > advertise PLATFORM support and, if the guest doesn't ack it, the host > > device would skip translation?=C2=A0 Or is that problematic for vfio? >=20 > Exactly that's problematic for security. > You can't allow guest driver to decide whether device skips security. Right. Because fundamentally, this *isn't* a property of the endpoint device, and doesn't live in virtio itself. 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