From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH] tpm: Add driver for TPM over virtio Date: Fri, 22 Feb 2019 17:07:19 -0500 Message-ID: <20190222170556-mutt-send-email-mst@kernel.org> References: <388c5b80-21a7-1e91-a11f-3a1c1432368b@gmail.com> <1550849416.2787.5.camel@HansenPartnership.com> <20190222160220-mutt-send-email-mst@kernel.org> <20190222213137.GZ17500@ziepe.ca> <20190222215923.GB21427@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20190222215923.GB21427@linux.intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Jarkko Sakkinen Cc: dgreid@chromium.org, virtualization@lists.linux-foundation.org, James Bottomley , Jason Gunthorpe , linux-integrity@vger.kernel.org, Peter Huewe , apronin@chromium.org, David Tolnay List-Id: virtualization@lists.linuxfoundation.org On Fri, Feb 22, 2019 at 11:59:23PM +0200, Jarkko Sakkinen wrote: > On Fri, Feb 22, 2019 at 02:31:37PM -0700, Jason Gunthorpe wrote: > > On Fri, Feb 22, 2019 at 04:16:01PM -0500, Michael S. Tsirkin wrote: > > > On Fri, Feb 22, 2019 at 07:30:16AM -0800, James Bottomley wrote: > > > > On Thu, 2019-02-21 at 18:14 -0800, David Tolnay wrote: > > > > > Add a config TCG_VIRTIO_VTPM which enables a driver providing the > > > > > guest kernel side of TPM over virtio. > > > > > > > > What's the use case for using this over the current non-virtio vTPM?. > > > > I always thought virtio was about guest to host transport efficiency, > > > > but the phsical TPM, being connected over a very slow bus, is about as > > > > inefficient as you can get in that regard, so why do we need to use > > > > virtio to drive the virtual one? > > > > > > I can't say for sure about TPM. > > > > > > But generally there are many reasons to do virtio rather than emulating > > > a hardware device. > > > > We already have a xen 'virtioish' TPM driver, so I don't think there > > is a good reason to block a virtio driver if someone cares about > > it. There are enough good reasons to prefer virtio to other options, > > IMHO. > > > > Provided it meets the general requirements for new virtio stuff you > > outlined. > > Yeah, absolutely we can consider this. > > For me it boils down to testing and documentation part. > > No plans to merge code that I'm unable to run... > > /Jarkko I do this sometimes. One can't require samples for all supported hardware. If I can check that code matches spec, I might settle for that. -- MST