From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-comment-return-657-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 6898C985B92 for ; Mon, 25 Feb 2019 23:45:09 +0000 (UTC) Date: Mon, 25 Feb 2019 18:45:05 -0500 From: "Michael S. Tsirkin" Message-ID: <20190225183821-mutt-send-email-mst@kernel.org> References: <20190225083700-mutt-send-email-mst@kernel.org> <20190225151735-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: [virtio-comment] Re: RFC: virtio-hostmem (+ Continuation of discussion from [virtio-dev] Memory sharing device) To: Roman Kiryanov Cc: Frank Yang , virtio-comment@lists.oasis-open.org, Cornelia Huck , Gerd Hoffmann , Stefan Hajnoczi , "Dr. David Alan Gilbert" List-ID: On Mon, Feb 25, 2019 at 03:08:19PM -0800, Roman Kiryanov wrote: > Michael, thank you for your comments. > > > I'm not sure how does above answer the comment. > > Sorry for leaving this unclear, our guest driver tells the > device guest's page size and then we do aligning-unaligning. This might work. Note that host page size might be different. If it's bigger host needs to be careful about allocating full host pages anyway. > > To try and put things in your terms, if you try to map a range of memory > > you get access to a page that can be bigger than the range you asked > > for. > > This is correct. > > > It can cause two ranges to violate a security boundary, cause > > information leaks, etc. > > Could you please correct me if I am wrong. If I ask glMapBufferRange > (without hosts and guests) for a 1K buffer with 4K pages, I will have > access to other 3K. If a driver decides to put sensitive bits there - > will this be the same situation? Sounds similar. > We assume pages are not shared between processes. > If this assumption does not work then it is hard to share arbitrary pointers. > > Regards, > Roman. Right. Details on how memory is allocated in the proposed scheme are scant but above I think shows that it can't all be up to guest. -- MST This publicly archived list offers a means to provide input to the OASIS Virtual I/O Device (VIRTIO) TC. In order to verify user consent to the Feedback License terms and to minimize spam in the list archive, subscription is required before posting. Subscribe: virtio-comment-subscribe@lists.oasis-open.org Unsubscribe: virtio-comment-unsubscribe@lists.oasis-open.org List help: virtio-comment-help@lists.oasis-open.org List archive: https://lists.oasis-open.org/archives/virtio-comment/ Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lists Committee: https://www.oasis-open.org/committees/virtio/ Join OASIS: https://www.oasis-open.org/join/