From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B817C43331 for ; Mon, 11 Nov 2019 15:36:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 61B0421783 for ; Mon, 11 Nov 2019 15:36:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726877AbfKKPgr (ORCPT ); Mon, 11 Nov 2019 10:36:47 -0500 Received: from mga09.intel.com ([134.134.136.24]:60068 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726832AbfKKPgq (ORCPT ); Mon, 11 Nov 2019 10:36:46 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 11 Nov 2019 07:36:45 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,293,1569308400"; d="scan'208";a="215709477" Received: from jlahtine-desk.ger.corp.intel.com ([10.252.20.50]) by orsmga002.jf.intel.com with ESMTP; 11 Nov 2019 07:36:39 -0800 Message-ID: Subject: Re: [virtio-dev] Re: guest / host buffer sharing ... From: Liam Girdwood To: David Stevens , Stefan Hajnoczi Cc: Gerd Hoffmann , Keiichi Watanabe , geoff@hostfission.com, virtio-dev@lists.oasis-open.org, Alex Lau , Alexandre Courbot , qemu-devel@nongnu.org, Tomasz Figa , Hans Verkuil , Daniel Vetter , =?ISO-8859-1?Q?St=E9phane?= Marchesin , Dylan Reid , Gurchetan Singh , Dmitry Morozov , Pawel Osciak , Linux Media Mailing List Date: Mon, 11 Nov 2019 15:36:38 +0000 In-Reply-To: References: <20191105105456.7xbhtistnbp272lj@sirius.home.kraxel.org> <20191106084344.GB189998@stefanha-x1.localdomain> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Mon, 2019-11-11 at 12:04 +0900, David Stevens wrote: > Having a centralized buffer allocator device is one way to deal with > sharing buffers, since it gives a definitive buffer identifier that > can be used by all drivers/devices to refer to the buffer. That being > said, I think the device as proposed is insufficient, as such a > centralized buffer allocator should probably be responsible for > allocating all shared buffers, not just linear guest ram buffers. This would work for audio. I need to be able to :- 1) Allocate buffers on guests that I can pass as SG physical pages to DMA engine (via privileged VM driver) for audio data. Can be any memory as long as it's DMA-able. 2) Export hardware mailbox memory (in a real device PCI BAR) as RO to each guest to give guests low latency information on each audio stream. To support use cases like voice calls, gaming, system notifications and general audio processing. Liam