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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 389E4C83003 for ; Wed, 29 Apr 2020 10:34:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0FCA4206F0 for ; Wed, 29 Apr 2020 10:34:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="iCU++Bv+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726599AbgD2Ke5 (ORCPT ); Wed, 29 Apr 2020 06:34:57 -0400 Received: from mail26.static.mailgun.info ([104.130.122.26]:40801 "EHLO mail26.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726355AbgD2Ke4 (ORCPT ); Wed, 29 Apr 2020 06:34:56 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1588156496; h=In-Reply-To: Content-Type: MIME-Version: References: Reply-To: Message-ID: Subject: Cc: To: From: Date: Sender; bh=XB7BUC3ojRcHv6kGtFh287OR6Fh4f+iq/qyjT7C3JuI=; b=iCU++Bv+Fm9kHF8lUvT8DTEFvoU0HruoM+3/+9e1we4Bjb9Cw6nXeNuNdyq5zsbRqwrEyWbU b8xrHW5GY0ZKyyjD/LMk/y2j0s+wVN/Jyi3XuxYKIKaT14tyydmXF8q/OMZ8yWI3jB25UAna I6GpDJKVtQ3MILqLI9h/zjz/gF4= X-Mailgun-Sending-Ip: 104.130.122.26 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by mxa.mailgun.org with ESMTP id 5ea9584a.7f04b35b6298-smtp-out-n04; Wed, 29 Apr 2020 10:34:50 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 77595C4478C; Wed, 29 Apr 2020 10:34:48 +0000 (UTC) Received: from quicinc.com (blr-bdr-fw-01_GlobalNAT_AllZones-Outside.qualcomm.com [103.229.18.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: svaddagi) by smtp.codeaurora.org (Postfix) with ESMTPSA id 8502CC433D2; Wed, 29 Apr 2020 10:34:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 8502CC433D2 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=vatsa@codeaurora.org Date: Wed, 29 Apr 2020 16:04:40 +0530 From: Srivatsa Vaddagiri To: "Michael S. Tsirkin" Cc: Lu Baolu , tsoni@codeaurora.org, virtio-dev@lists.oasis-open.org, konrad.wilk@oracle.com, jan.kiszka@siemens.com, jasowang@redhat.com, christoffer.dall@arm.com, virtualization@lists.linux-foundation.org, alex.bennee@linaro.org, iommu@lists.linux-foundation.org, stefano.stabellini@xilinx.com, will@kernel.org, linux-kernel@vger.kernel.org, pratikp@codeaurora.org Subject: Re: [PATCH 5/5] virtio: Add bounce DMA ops Message-ID: <20200429103438.GF5097@quicinc.com> Reply-To: Srivatsa Vaddagiri References: <20200428174952.GA5097@quicinc.com> <20200428163448-mutt-send-email-mst@kernel.org> <275eba4b-dd35-aa95-b2e3-9c5cbf7c6d71@linux.intel.com> <20200429004531-mutt-send-email-mst@kernel.org> <20200429023842-mutt-send-email-mst@kernel.org> <20200429094410.GD5097@quicinc.com> <20200429055125-mutt-send-email-mst@kernel.org> <20200429100953.GE5097@quicinc.com> <20200429061621-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20200429061621-mutt-send-email-mst@kernel.org> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Michael S. Tsirkin [2020-04-29 06:20:48]: > On Wed, Apr 29, 2020 at 03:39:53PM +0530, Srivatsa Vaddagiri wrote: > > That would still not work I think where swiotlb is used for pass-thr devices > > (when private memory is fine) as well as virtio devices (when shared memory is > > required). > > So that is a separate question. When there are multiple untrusted > devices, at the moment it looks like a single bounce buffer is used. > > Which to me seems like a security problem, I think we should protect > untrusted devices from each other. I think as first step, let me see if we can make swiotlb driver accept a target memory segment as its working area. That may suffice our needs I think. A subsequent step could be to make swiotlb driver recognize multiple pools. -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation