On Fri, Feb 22, 2019 at 02:24:55PM -0800, David Tolnay wrote: > On 2/22/19 1:50 PM, Jarkko Sakkinen wrote: > > On Fri, Feb 22, 2019 at 04:25:08PM -0500, Michael S. Tsirkin wrote: > >> On Fri, Feb 22, 2019 at 09:33:05PM +0200, Jarkko Sakkinen wrote: > >>> 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. > >>> > >>> ... and I did your response total three times and did not find any > >>> causality of any sort from anything. > >>> > >>> /Jarkko > >> > >> Thanks for spending the time reading my response. What was included in > >> it was a general suggestion for a virtio based driver to be acceptable > >> in upstream Linux. > >> > >> You pointed out that a pointer to a prototype implementation in Rust > >> isn't relevant. However, FYI just posting guest code and asking for it > >> to be merged alone won't work for a virtio driver either. I am merely > >> trying to speed things up instead of having the contributor repost with > >> a tweaked commit log just to immediately get another set of nacks. > > > > I did not say anything about relevance of any implementation. I tried to > > mainly point out that looking at random source files implemented with a > > relatively alien language to most does not really make a case. > > > > Things that would help to move this forward: > > > > - Documentation of the stack, nothing spectacular but more like how it > > works in practical terms. > > - Sufficiently easy ways to test the code. > > - Explain in the commit message why we want this. > > > > /Jarkko > > > Thanks Jarkko, I respect all of the points you've raised and you are absolutely > correct to ask for a spec and/or spec-quality documentation, detailed testing > steps for exercising this driver in qemu or crosvm, and strong justification for > the new driver. I do not require spec quality documentation. Just a few paragraphs of what is in crosvm, kernel etc. and something about inner workings to get a rough idea. No need for TCG level spec for this :-) Something in the spirit of what you could bundle under Documentation/ in the kernel tree. Maybe you could consider putting something there and make this a patch set? To get started with testing this properly is there anywhere documentation on "here's how you compile and run crosvm"? If I can run it myself it will be easier for me to understand what happens even without a spec. Clone the repository and cargo build? /Jarkko
