From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f175.google.com (mail-wi0-f175.google.com [209.85.212.175]) by dpdk.org (Postfix) with ESMTP id 130578E7B for ; Wed, 30 Sep 2015 23:00:29 +0200 (CEST) Received: by wicfx3 with SMTP id fx3so1208006wic.0 for ; Wed, 30 Sep 2015 14:00:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:to:references:cc:from:message-id:date :user-agent:mime-version:in-reply-to:content-type :content-transfer-encoding; bh=Jda18+dHTiB2uXZN/sIaKZPESsR+2ktjosqeZHJ/Y7I=; b=HZqwMuBXijld/nBtt1X//WJTo58cPoGV7JCVQ0x+gQ2Tko1Bpzg/8sphOHMIIc4qgQ 5gAmNHRM4YTejSlgfOXv86eSrckc4fe6lCxsL0OC1pqolTBi2WoLAXIIpaSEFsAouaMa 18mW+hZ0TCtDbXCrVIxQDzvGfLThWxCvJ5xxheAMVMKngJr9yo+iiik2iOfYTNPqHmuu AUxPf2CIDSQxpj04+bs6SidDuB0QM3zpFFheVDeNIdgAo0DaaavTDrN5vwclsDczk4WW VpzZGcxC9jXUvtFk0nEgHM66aSW4lOzo0THr/szZ1ITdcZpi6rrxPK1Mkw6QZAcoNnBf S0Iw== X-Gm-Message-State: ALoCoQm3eyyIPZ97dzZYyWi8xTR6YDwd+60ulmCxcSbL9mPKHZb9AY4lgmxFXTX8EvV/HMNqiKqN X-Received: by 10.180.106.229 with SMTP id gx5mr35604223wib.24.1443646828232; Wed, 30 Sep 2015 14:00:28 -0700 (PDT) Received: from [10.0.0.4] (bzq-109-64-134-34.red.bezeqint.net. [109.64.134.34]) by smtp.googlemail.com with ESMTPSA id hk5sm2559977wjb.6.2015.09.30.14.00.26 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 30 Sep 2015 14:00:27 -0700 (PDT) To: "Michael S. Tsirkin" References: <20150930143927-mutt-send-email-mst@redhat.com> <560BCD2F.5060505@cloudius-systems.com> <20150930150115-mutt-send-email-mst@redhat.com> <560BD284.7040505@cloudius-systems.com> <20150930151632-mutt-send-email-mst@redhat.com> <560BDE24.8000308@scylladb.com> <20150930165359-mutt-send-email-mst@redhat.com> <560BF782.4070308@scylladb.com> <20150930175848-mutt-send-email-mst@redhat.com> <560C0171.7080507@scylladb.com> <20150930204016.GA29975@redhat.com> From: Avi Kivity Message-ID: <560C4D69.5010403@scylladb.com> Date: Thu, 1 Oct 2015 00:00:25 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20150930204016.GA29975@redhat.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] Having troubles binding an SR-IOV VF to uio_pci_generic on Amazon instance X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 30 Sep 2015 21:00:29 -0000 On 09/30/2015 11:40 PM, Michael S. Tsirkin wrote: > On Wed, Sep 30, 2015 at 06:36:17PM +0300, Avi Kivity wrote: >> As it happens, you're removing the functionality from the users who have no >> other option. They can't use vfio because it doesn't work on virtualized >> setups. > ... > >> Root can already do anything. > I think there's a contradiction between the two claims above. Yes, root can replace the current kernel with a patched kernel. In that sense, root can do anything, and the kernel is complete. Now let's stop playing word games. >> So what security issue is there? > A buggy userspace can and will corrupt kernel memory. > > ... > >> And for what, to prevent >> root from touching memory via dma that they can access in a million other >> ways? > So one can be reasonably sure a kernel oops is not a result of a > userspace bug. > That's not security. It's a legitimate concern though, one that is addressed by tainting the kernel.