From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752432AbbJFHeL (ORCPT ); Tue, 6 Oct 2015 03:34:11 -0400 Received: from mail-pa0-f50.google.com ([209.85.220.50]:34232 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751794AbbJFHeJ (ORCPT ); Tue, 6 Oct 2015 03:34:09 -0400 Date: Tue, 6 Oct 2015 08:33:56 +0100 From: Stephen Hemminger To: "Michael S. Tsirkin" Cc: Vladislav Zolotarov , hjk@hansjkoch.de, dev@dpdk.org, gregkh@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [dpdk-dev] [PATCH 2/2] uio: new driver to support PCI MSI-X Message-ID: <20151006083356.3da3defa@uryu.home.lan> In-Reply-To: <20151006013000-mutt-send-email-mst@redhat.com> References: <1443652138-31782-1-git-send-email-stephen@networkplumber.org> <1443652138-31782-3-git-send-email-stephen@networkplumber.org> <20151001104505-mutt-send-email-mst@redhat.com> <20151005215455.GA7608@redhat.com> <20151006013000-mutt-send-email-mst@redhat.com> X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.25; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Other than implementation objections, so far the two main arguments against this reduce to: 1. If you allow UIO ioctl then it opens an API hook for all the crap out of tree UIO drivers to do what they want. 2. If you allow UIO MSI-X then you are expanding the usage of userspace device access in an insecure manner. Another alternative which I explored was making a version of VFIO that works without IOMMU. It solves #1 but actually increases the likely negative response to arguent #2. This would keep same API, and avoid having to modify UIO. But we would still have the same (if not more resistance) from IOMMU developers who believe all systems have to be secure against root.