From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [RFC 0/4] Virtio uses DMA API for all devices Date: Mon, 6 Aug 2018 23:12:13 -0700 Message-ID: <20180807061213.GA32709@infradead.org> References: <20180803070507.GA1344@infradead.org> <20180803220443-mutt-send-email-mst@kernel.org> <051fd78e15595b414839fa8f9d445b9f4d7576c6.camel@kernel.crashing.org> <20180805031046-mutt-send-email-mst@kernel.org> <20180806164106-mutt-send-email-mst@kernel.org> <20180806233024-mutt-send-email-mst@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20180806233024-mutt-send-email-mst@kernel.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: "Michael S. Tsirkin" Cc: robh@kernel.org, srikar@linux.vnet.ibm.com, Benjamin Herrenschmidt , Will Deacon , linux-kernel@vger.kernel.org, linuxram@us.ibm.com, virtualization@lists.linux-foundation.org, Christoph Hellwig , jean-philippe.brucker@arm.com, paulus@samba.org, marc.zyngier@arm.com, mpe@ellerman.id.au, joe@perches.com, robin.murphy@arm.com, david@gibson.dropbear.id.au, linuxppc-dev@lists.ozlabs.org, elfring@users.sourceforge.net, haren@linux.vnet.ibm.com, Anshuman Khandual List-Id: virtualization@lists.linuxfoundation.org On Mon, Aug 06, 2018 at 11:35:39PM +0300, Michael S. Tsirkin wrote: > > As I said replying to Christoph, we are "leaking" into the interface > > something here that is really what's the VM is doing to itself, which > > is to stash its memory away in an inaccessible place. > > > > Cheers, > > Ben. > > I think Christoph merely objects to the specific implementation. If > instead you do something like tweak dev->bus_dma_mask for the virtio > device I think he won't object. As long as we also document how dev->bus_dma_mask is tweaked for this particular virtual bus, yes.