- Spectrum Development - spectrum-os.org

Spam on this list
by Alyssa Ross 18 May '20

18 May '20

Hi, Apologies for the recent spam message on the list. It got through due to a misconfigured spam filter. Should be fixed now. Let me know if you see anything else unusual. :)

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This Week in Spectrum, 2020-W20
by Alyssa Ross 17 May '20

17 May '20

It feels like things are finally starting to come together. Infrastructure -------------- Server memory upgraded. We should now be able to handle more than one person cloning Spectrum's nixpkgs repo at once! Documentation ------------- I added a much requested page[1] to the website with a few tasks a potential contributor might want to look into. More to come here, too! [1]: https://spectrum-os.org/todo.html virtio_wl --------- I wrote a simple guest C program that connected to a host socket over virtio_wl, and sent some messages back and forth. In doing this, I've ended up with a nice set of generic functions for interacting with virtio_wl -- virtio_wl_connect(), virtio_wl_send(), etc. This is nice, because it allows me to treat virtio_wl inside a guest much like a regular socket (albeit one that can only be interacted with using a custom set of functions). Otherwise, I'd have to do ioctl operations every time (which seems to be what the various virtio_wl-using Chromium OS components do). Having a simple test program (rather than integrating directly into wlroots) gives me a more simple environment with which to test the other end of this connection. crosvm ------ I implemented a little Rust server that listens on a Unix stream socket. When it receives a message (consisting of an identifier {for debug purposes} and a size), it will allocate a memfd of the requested size, and then send that back to the socket, along with a status byte indicating success or failure. I then integrated this program into crosvm, so it is started as part of the VM initialization, and exposed over virtio_wl as an additional socket. Integrating this into crosvm required some careful thought, because there's no precedent in crosvm for a virtio_wl server of this sort. It has almost nothing with the existing concept in crosvm of a "device", which is something that communicates with a guest kernel driver over PCI. So Spectrum's crosvm now has the concept of "servers". I can see us wanting to provide other VM services over virtio_wl in the future. It allows us to exchange various resources between host and guest (or between guests) without having to write a kernel driver specific to each task. This all now works well enough that my program inside the VM can request a chunk of memory, and receive back something that looks a bit like a memfd, that can then be sent back to the host over a virtio_wl socket. It was great to see this working the first time! One thing crosvm devices do that I would also like to apply to this type of server is sandboxing. The sandboxing mechanism used in crosvm is pretty generic (it's really just a thin wrapper around Minijail[2]), so it should be straightforward to reuse. I just have to understand a bit better how to use it. The other crosvm change I still need to make is to put this functionality behind a command line flag. Most VMs should not be able to give themselves extra memory this way -- really only the Wayland compositor should be using it. I should also impose some upper bound on how much memory is allowed to be allocated this way. Such a limit will probably get harder to add (from a testing point of view) the longer I wait. [2]: https://lwn.net/Articles/700557/ So, at lot of very focused progress this week. From here I plan to finish up the crosvm stuff, and then integrate this protocol into wlroots. Then, not too long from now, we'll finally be able to move the Wayland compositor into its own VM, separate from applications. Exciting! There will also probably be a Chromium OS release next week, which will require some updates in Spectrum. If all goes well, I won't actually be the one doing that this time. ;)

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[PATCH www] todo.html: fix 'appears' -> 'appeals'
by Vincent Ambo 15 May '20

15 May '20

Hello world o/ --- todo.html | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/todo.html b/todo.html index fd8bc04..b8c091a 100644 --- a/todo.html +++ b/todo.html @@ -26,7 +26,7 @@ system available to experiment with yet. <p> Here are some ideas for contributions, roughly ordered by priority. -If working on any of these appears to you, even if you don't +If working on any of these appeals to you, even if you don't understand all the parts involved, we'd be happy to provide mentorship and support. Just reach out on <a href="participating.html#irc">IRC</a> or email -- 2.26.2.761.g0e0b3e54be-goog

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oops
by impaqt 13 May '20

13 May '20

sorry, this isn't devel-subscribe...

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sign me up
by impaqt 13 May '20

13 May '20

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This Week in Spectrum, 2020-W19
by Alyssa Ross 10 May '20

10 May '20

This week, I want to give a special shoutout to Cole Helbling, who sent three patches to improve our documentation. Non-Alyssa Spectrum patches are quite rare at the moment, so it was very very nice to get these all at once. Thanks Cole! This week has mostly been tidying up loose ends and working on documentation. But there's some good, concrete progress as well. Website ------- <https://spectrum-os.org/> now links directly to my blog and This Week in Spectrum, so that people who come to the website can more easily see that development is ongoing and progress is being made[1]. I've also made it a little more obvious how to find the IRC channel and mailing lists from the homepage[2], because a conversation on the fediverse made me realise that wasn't clear at all before. Cole fixed the advice in the website's CONTRIBUTING file on sending patches for the website[3]. I had written to set Git's "sendemail.subjectPrefix" configuration option, but the option is actually called "format.subjectPrefix". Cole fixed a broken link[4], and I made the incorrect URL redirect to the right one as well, just in case. [1]: https://spectrum-os.org/git/www/commit/?id=8f37213cfd4d5dbd4a982bfc1899a3b3… [2]: https://spectrum-os.org/git/www/commit/?id=6d1ce779016cd84c0413b225355715e5… [3]: https://spectrum-os.org/git/www/commit/?id=8f37213cfd4d5dbd4a982bfc1899a3b3… [4]: https://spectrum-os.org/git/www/commit/?id=13c860e1e5bb02fce683012b851c4451… Developer manual ---------------- Did you know there's a developer manual[5] for Spectrum? There's not a lot in there yet, so for now it might not be all that useful, but it will be one day! I added a section about how to hack on Spectrum's crosvm, because it can be a bit non-obvious how to get up and running with it. I got some great feedback on it on IRC, and a diff from Cole with some fixes. Thanks to everybody who gave me feedback and helped get that documentation into shape. Setting up a crosvm build still isn't all that easy, but at least it's documented. [5]: https://spectrum-os.org/doc/developer-manual.html Infrastructure -------------- Two(?) people trying to clone all of Nixpkgs from the tiny VPS running spectrum-os.org caused the server to run out of memory and return 504 to those clones. It's quite important that people are able to get Spectrum's code, so I've arranged for the VPS to be upgraded with more memory, and so now I just need to reboot the machine so it picks it up. I plan on doing this tomorrow, since there's less likely to be mailing list traffic then than there is immediately after I send this. In the medium term I'll host all this stuff on a more sensible machine, because it's quite clear the workload on this server (which also runs some other stuff) is starting to get beyond the "tiny VPS" territory. IRC --- Activity in #spectrum has really picked up all of a sudden. Hundreds of messages were sent in the second half of this week, mostly talking either about Spectrum or about the future of secure computing in general, and I'm extremely here for all of it. The best thing is that I wasn't even around for most of these conversations! It's hugely motivating to me to feel that people are so interested in Spectrum, and it's great to have people with all sorts of useful knowledge and questions around. If you weren't there, I recommend actually checking out the logs from this period[6], because the conversations being had were just a great read full of interesting stuff. #spectrum feels like it's now at the point where you can start a discussion about secure computing, and be confident that you'll get at least a couple of extremely knowledgeable people involved in the conversation, and that's just fantastic. [6]: https://logs.spectrum-os.org/spectrum/2020-05-06 Wayfire ------- I replaced Sway in the test VM derivation with our newly packaged Wayfire. I was worried at first because wf-shell wasn't starting properly, but strace helped me realise that wf-shell likes HOME to be set, and I hadn't actually done that in the VMs yet. So now that works. There hasn't been much movement on my Wayfire PRs, or my PR to add Wayfire to upstream Nixpkgs, and that's down to me. I felt like after working on it all week last week, I needed a bit of a break. I'll try to get back to it next week so all those PRs can be gotten over the line. crosvm ------ I merged the latest crosvm changes from Google into Spectrum's crosvm tree. Doing this at the moment takes quite a while, because my work-in-progress "interguest" branch has about 50 commits that have to be rebased onto the new master, and quite a lot of those usually result in conflicts. This won't be as much of a problem once that code is ready to be included in master, because updating then will just be a single merge commit, but for now it's a bit of a pain, especially since I try to make sure every commit works. I haven't had much of a look over what's changed yet. There's usually at least one cool new toy to be excited about when I merge Google's crosvm, though, so I look forward to finding out what it is this time. I think that's it for this week, although honestly there have been so many different things going on I've probably missed something. Hopefully next week will be a bit more focused and I'll make more progress with interguest communication. This week, though, we've made some great improvements in several important areas. I'm optimistic that the increased IRC and patch volume are a sign of things to come. I'm looking forward to seeing where things will go from here. :)

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[PATCH www] CONTRIBUTING: fix `git config` suggestion
by Cole Helbling 09 May '20

09 May '20

format-patch is the component that adds to the prefix, not send-email. --- CONTRIBUTING | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/CONTRIBUTING b/CONTRIBUTING index 2f1f8b2..7ec8fba 100644 --- a/CONTRIBUTING +++ b/CONTRIBUTING @@ -23,8 +23,8 @@ automatically prepend a prefix to the subject line of every patch message sent by it in a given repository. You can configure it by running the following command in this Git repository: - git config sendemail.subjectPrefix "PATCH www" + git config format.subjectPrefix "PATCH www" From now on, git-send-email(1) will automatically add "[PATCH www]" to the start of every patch sent for this repository, instead of the -default "[PATCH]". \ No newline at end of file +default "[PATCH]". -- 2.26.2

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[PATCH] doc: fix 404ing link
by Cole Helbling 09 May '20

09 May '20

--- doc/index.html | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/doc/index.html b/doc/index.html index c8dea1d..812793b 100644 --- a/doc/index.html +++ b/doc/index.html @@ -22,7 +22,7 @@ <ul> <li><a href="https://spectrum-os.org/doc/developer-manual.html">Developer manual</a> - <li><a href="https://spectrum-os.org/doc/crosvm">crosvm rustdoc</a> + <li><a href="https://spectrum-os.org/doc/crosvm/crosvm/">crosvm rustdoc</a> </ul> <p> -- 2.26.2

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This week in Spectrum, 2020-W18
by Alyssa Ross 03 May '20

03 May '20

A belated Happy International Workers' Day. :) I had some other stuff going on this week but I'm still happy with what I got done. Wayfire ------- I've been working on packaging Wayfire in Nixpkgs so we can use it in Spectrum. (See last week's update for why I've chosen Wayfire for this.) This has required quite a bit of work on Wayfire itself, because up until now Wayfire has assumed that every component, including plugins, will be installed into Wayfire's prefix. With Nix, a package's prefix is only writable by that package, so we need to make some changes to Wayfire to support each component having its own prefix. This is necessary even for our simple case because even a basic Wayfire setup has at least one plugin to provide the desktop shell. Everything is supposed to be a plugin, after all. And we'll want to add our own plugins at some point. To implement plugins in other search paths, I added two environment variables WAYFIRE_PLUGIN_PATH (for libraries) and WAYFIRE_PLUGIN_XML_PATH (for the XML files that define Wayfire plugin options). These are then searched in addition to Wayfire's prefix. Support for plugins coming from multiple prefixes required some small changes in several parts of the Wayfire ecosystem. Wayfire has so far proven to be a very friendly upstream. They understood the problem I was having, even though it's less of an issue on traditional distributions, and I always got quick answers on IRC when I needed to ask for advice on implementing the search paths. Here's the issue I filed describing the need for search paths: https://github.com/WayfireWM/wayfire/issues/493 And here are all the pull requests I made to implement them across the ecosystem: https://github.com/WayfireWM/wayfire/pull/496 https://github.com/WayfireWM/wf-config/pull/25 https://github.com/WayfireWM/wayfire/pull/497 https://github.com/WayfireWM/wf-shell/pull/52 https://github.com/WayfireWM/wf-shell/pull/53 https://github.com/WayfireWM/wcm/pull/17 https://github.com/WayfireWM/wf-shell/pull/54 https://github.com/WayfireWM/wcm/pull/18 With these changes, I can have Wayfire all nicely packaged up. We can even provide a nice Nix interface for configuring a Wayfire with some specific plugins: (wayfireApplications.withPlugins (plugins: with plugins; [ wf-shell ])).wayfire I made a pull request to add Wayfire, with the interface demonstrated above, to Nixpkgs: https://github.com/NixOS/nixpkgs/pull/86606 Unbeknownst to me, while I was working on this, another PR was also opened to add the latest version of Wayfire to Nixpkgs: https://github.com/NixOS/nixpkgs/pull/86569 This PR does a good job of making the basic Wayfire installation work, but it doesn't support extra plugins. Still, it's likely that if this had been available before I started my work, it would have been good enough for us for now. This sort of thing is always a risk, and even if I hadn't done the Wayfire work now I'd have had to come back later anyway to do plugins, so it's not too bad. The author of that PR and I have agreed to work together from here to get Wayfire into Nixpkgs, using my PR as a base because it has the plugins support. So, hopefully by the time I write my next status update all my Wayfire pull requests will have been merged, and Wayfire will be in Nixpkgs. Reviews on the Nixpkgs PR in particular are very much appreciated. :) From here, I'll start trying to modify Wayfire/wlroots to make it request host memory rather than allocating its own, as described in last week's status update. I had a quick look, and it appears that there aren't many places these allocations are happening, so hopefully that shouldn't require too much modification. Then, we should be able to run an application in one VM, displayed on a compositor in another. :)

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This Week in Spectrum, 2020-W17
by Alyssa Ross 26 Apr '20

26 Apr '20

It's been a bit of a slow week, I'm afraid. spectrum-vm ----------- As mentioned last week, it was becoming extremely inconvenient to test out custom kernel/crosvm/rootfs builds by modifying a Nix expression every time. So I wrote spectrum-vm, a small program that takes command line arguments for kernel, crosvm, and rootfs paths to use, and falls back to pre-built defaults if any of those aren't specified. This makes turnaround time on testing different kernel builds much quicker, because they can be built incrementally outside of nix sandboxes. To make things more concrete, suppose I have built a kernel in /home/src/linux/arch/x86_64/boot/bzImage, and I want to test it with the Spectrum crosvm demo setup. I can run spectrum-vm -k /home/src/linux/arch/x86_64/boot/bzImage and I get a VM booted from that kernel, with no need to nix-build anything. By default, the launched VM will run Weston Terminal inside a Wayland compositor. But you can even replace this with a custom command: spectrum-vm -c 'echo "Hello, world!"' The implementation of that last bit is quite the hack. I'll leave figuring out how it works as an exercise to the reader. ;) spectrum-vm is available now in Spectrum's Nixpkgs as spectrumPackages.spectrum-vm, as of commit 817a1a9b0de30d8bbc2ad2e80a802d87c56e96ff. Implementing this has meant that the huge start-vm.nix file that used to exist on the crosvm-demo branch had to be split up into a bunch of discreet units. This is really great, because start-vm.nix was starting to grow enormous, and experimenting with changes was becoming A Problem. Now, that's all nice and modular under the new spectrumPackages namespace. And _that_ means that the crosvm-demo branch can finally go away, and Spectrum's Nixpkgs is no longer split across two branches. (The purpose of the separation was to avoid there being a horrible start-vm.nix file in the root on master.) So in addition to a lovely helpful tool, this has also resulted in much cleaner code. Yay! One feature I would still like to add is an option that maps to crosvm run's --shared-dir, to mount a directory into a VM over 9p. That would make getting code into a VM to test it extremely convenient. I haven't gotten around to it yet though. Guest memory sharing -------------------- Last week I shared a bunch of research I had done on sharing guest-allocated buffers with other VMs. I was hoping to avoid having to patch a Wayland compositor to request buffers from the host instead of allocating them itself, but I've since come to the conclusion that avoiding that won't be feasible, for now at least. Basically, the kernel primitives aren't there yet, and it would be silly for me, with almost zero kernel development experience, to attempt to write them. There are all sorts of horrible edge cases to think about, like what happens if the guest-allocated memory moves around. Compared to this, patching a Wayland compositor doesn't seem too bad. Having to go through a request/response over a vsock to the host will be a bit of a performance overhead compared to a smarter solution, but I think this kind of allocation happens rarely enough that it probably doesn't matter anyway. A nice middle ground would have been to use virtio-gpu resources rather than a custom message over a vsock. It would have been a much cleaner way to do it, and it might not even involve writing any kernel code, but the practical benefits of it would be extremely limited when contrasted with the time it would take me to implement that. I don't expect the approach I'm taking now of patching the Wayland compositor to necessarily be permanent. As I linked to last week, there are kernel efforts happening to add the necessary primitives to share guest allocations. At some point in the future we might be able to use them. And at basically any time we could switch to using virtio-gpu resources if somebody wanted to put in the work. Patching a compositor really isn't a big deal, though. It's unlikely Spectrum will support more than one compositor anyway, because we'll need to customise it to do things like Qubes-style window borders that are coloured based on security domain. And, even then, if we're using a wlroots-based compositor, it's probably only wlroots that needs patching, so in that case any other wlroots-based compositor would probably work. Speaking of compositors... Wayfire ------- If you know what Wayfire is, you're probably surprised to see it as an item in a Spectrum status update it. If you don't, Wayfire is a Wayland compositor notable for having a bunch of over-the-top Compiz-style graphical effects, like wobbly windows and the titular fire. I recommend checking out the demo videos on https://wayfire.org/ if you haven't seen them -- it's quite something. But I bring this up not because I think support for wobbly windows is imperative to Spectrum's chances of success, but because fundamentally Wayfire is just an extremely modular Wayland compositor. Virtually everything in Wayfire is implemented as a plugin. Switching between windows is a plugin, screen zoom is a plugin, and so on. This is really cool because in Spectrum we'll want to have, for example, coloured window decorations like in Qubes. With any other compositor, we'd have to hack that into the compositor internals somehow. With Wayfire, it can just be a plugin. Wayfire is also a pleasantly simple but featureful windowing experience. You can drag windows around, put two side by side by dragging them to screen edges, have multiple workspaces, etc. I think it will be straightforward enough to not be a problem for people coming to Spectrum regardless of their computing background, and powerful enough to not get in the way of Serious Computer Business. And anything missing could of course be implemented as a plugin. ;) So, I've been doing some work to package Wayfire in Nixpkgs. This is not all that easy, because Wayfire seems to assume that plugins will be installed into Wayfire's prefix. This isn't really possible with Nix unless you compile all the plugins along with Wayfire, so I'm working some patches for Wayfire to look up plugins in a search path specified as an environment variable, which on the Nix side we can then wrap in the idiomatic wayfireWithPackages style. My initial impressions of the Wayfire codebase are that it is relatively clean, and straightforward enough to understand. The core compositor is about 13000 SLoC, which is pleasantly small. That, unfortunately, is it for this week. I didn't get as much done as I'd hoped, but I did at least have loads of good thoughts about things to do later in Spectrum's development, that aren't quite concrete enough to put into words yet.

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