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 15:55:33 -0500 Message-ID: <20190222154838-mutt-send-email-mst@kernel.org> References: <388c5b80-21a7-1e91-a11f-3a1c1432368b@gmail.com> <20190222102610.GB5613@linux.intel.com> <20190222101728-mutt-send-email-mst@kernel.org> <20190222193156.GA6475@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: <20190222193156.GA6475@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, 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 09:31:56PM +0200, Jarkko Sakkinen wrote: > On Fri, Feb 22, 2019 at 10:23:02AM -0500, Michael S. Tsirkin wrote: > > On Fri, Feb 22, 2019 at 12:26:10PM +0200, Jarkko Sakkinen wrote: > > > On Thu, Feb 21, 2019 at 06:14:02PM -0800, David Tolnay wrote: > > > > Add a config TCG_VIRTIO_VTPM which enables a driver providing the guest > > > > kernel side of TPM over virtio. > > > > > > > > Use case: TPM support is needed for performing trusted work from within > > > > a virtual machine launched by Chrome OS. > > > > > > > > Tested inside crosvm, the Chrome OS virtual machine monitor. Crosvm's > > > > implementation of the virtio TPM device can be found in these two source > > > > files: > > > > > > > > - https://chromium.googlesource.com/chromiumos/platform/crosvm/+/18ce5713e6cb99c40aafec52b67c28ba12a44f31/devices/src/virtio/tpm.rs > > > > - https://chromium.googlesource.com/chromiumos/platform/crosvm/+/18ce5713e6cb99c40aafec52b67c28ba12a44f31/tpm2/src/lib.rs > > > > > > These files/links do not make sense for kernel testing. Please remove > > > them from the next version. > > > > To clarify generally for a virtio device we want > > - guest support > > - device support > > - spec > > > > If the device is implemented in qemu and guest in linux kernel, > > then there are lots of people familiar with these > > programming environments, so sometimes we merge > > guest and host code even if spec isn't written up at all. > > > > If you don't want to do that there's a small number of people who can > > properly review code, e.g. I don't think lots of people on this list are > > familiar with crosvm. One way to address this would be to build a QEMU > > implementation. Another would be to write up a spec. You can do both > > too :) > > I don't really understand your arguments. > > /Jarkko Jarkko, I am not making any argument at all. I am trying to suggest ways for this driver to get upstream. And I am saying that while I agree availability of an implementation in crosvm isn't sufficient, availability of a software device implementation in QEMU is not an absolute prerequisite for including a virtio driver in Linux. If there's a virtio spec explaining how to write one, that can be enough. -- MST