From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:55454) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RaWMe-0003xm-Ui for qemu-devel@nongnu.org; Tue, 13 Dec 2011 12:42:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RaWMa-0001hY-HE for qemu-devel@nongnu.org; Tue, 13 Dec 2011 12:42:04 -0500 Received: from mail-yw0-f45.google.com ([209.85.213.45]:55524) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RaWMa-0001hU-88 for qemu-devel@nongnu.org; Tue, 13 Dec 2011 12:42:00 -0500 Received: by yhgg71 with SMTP id g71so687282yhg.4 for ; Tue, 13 Dec 2011 09:41:59 -0800 (PST) Message-ID: <4EE78E64.2080807@codemonkey.ws> Date: Tue, 13 Dec 2011 11:41:56 -0600 From: Anthony Liguori MIME-Version: 1.0 References: <1323717136-21661-1-git-send-email-stefanb@linux.vnet.ibm.com> <4EE68DFF.6050908@codemonkey.ws> <4EE6987F.1000100@linux.vnet.ibm.com> <201112130451.44284.paul@codesourcery.com> <4EE74A45.8000306@linux.vnet.ibm.com> <20111213135135.GC13107@redhat.com> In-Reply-To: <20111213135135.GC13107@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH V13 6/7] Introduce --enable-tpm-passthrough configure option List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: qemu-devel@nongnu.org, Paul Brook , andreas.niederl@iaik.tugraz.at, Stefan Berger On 12/13/2011 07:51 AM, Michael S. Tsirkin wrote: > On Tue, Dec 13, 2011 at 07:51:17AM -0500, Stefan Berger wrote: >> On 12/12/2011 11:51 PM, Paul Brook wrote: >>>>>> +tpm_passthrough="no" >>>>> Same as before, please probe for existence. >>>> We would be probing for /dev/tpm0. Is that really what we want that this >>>> driver only gets compiled if /dev/tpm0 is (currently) available? >>> If what you say is true then this code should always be enabled. >>> >> Michael Tsirkin previously requested that there be an option for the >> TPM passthrough driver to be selectively enabled since at least >> using /dev/tpm0 may not be what everybody wants. The passthrough >> driver at some point will also be able to use sockets to communicate >> with a TPM when a file descriptor is passed to Qemu, so maybe that >> changes then? >> >> >> Stefan > > The passthrough as it is, is pretty easy to misuse. > This is a hardware problem, not software, and > I don't think it's fixable. Can you elaborate? And can this be documented such that users are aware of this. Regards, Anthony Liguori > > So I do not think all downstreams will want to support this > mode, making it easy to disable this is IMO important. >