From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-5482-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis.ws5.connectedcommunity.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 01B0F9860BA for ; Thu, 21 Feb 2019 10:03:55 +0000 (UTC) Date: Thu, 21 Feb 2019 10:03:30 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20190221100330.GC2605@work-vm> References: <20190211092943-mutt-send-email-mst@kernel.org> <20190219071222.jjebzcbh55kwlspn@sirius.home.kraxel.org> <20190220070213.3uetjgzzlf5qojan@sirius.home.kraxel.org> <20190221072950.tcii5np5dsk4wvyd@sirius.home.kraxel.org> <20190221092455.GB2605@work-vm> <20190221095902.mfa54mu7b4q5524p@sirius.home.kraxel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190221095902.mfa54mu7b4q5524p@sirius.home.kraxel.org> Subject: Re: [virtio-dev] Memory sharing device To: Gerd Hoffmann Cc: Frank Yang , "Michael S. Tsirkin" , Roman Kiryanov , Stefan Hajnoczi , virtio-dev@lists.oasis-open.org List-ID: * Gerd Hoffmann (kraxel@redhat.com) wrote: > Hi, > > > > Note: I think using a pci memory bar (aka host memory mapped into the > > > guest) as backing storage for dma-bufs isn't going to work. > > > > (Not knowing dma-bufs) but could you explain why? > > Many places in the linux kernel assume dma-bufs are built out of normal > ram pages (i.e. something backed by struct page). Which is not the case > for pci memory bars which are typically ioremapped() (completely or in > chunks) to access them. Ah OK, so it's the view from inside the guest that's the problem. Dave > cheers, > Gerd > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org > For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org