From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex =?utf-8?Q?Benn=C3=A9e?= Subject: Re: [Qemu-devel] KVM call for 2017-03-14 Date: Mon, 13 Mar 2017 12:50:29 +0000 Message-ID: <877f3tqr1m.fsf@linaro.org> References: <87tw6y8bs8.fsf@secure.mitica> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: Juan Quintela , KVM devel mailing list , QEMU Developer To: Peter Maydell Return-path: Received: from mail-wr0-f179.google.com ([209.85.128.179]:36316 "EHLO mail-wr0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752346AbdCMMuW (ORCPT ); Mon, 13 Mar 2017 08:50:22 -0400 Received: by mail-wr0-f179.google.com with SMTP id u108so102754668wrb.3 for ; Mon, 13 Mar 2017 05:50:20 -0700 (PDT) In-reply-to: Sender: kvm-owner@vger.kernel.org List-ID: Peter Maydell writes: > On 12 March 2017 at 21:45, Juan Quintela wrote: >> >> >> Hi >> >> Please, send any topic that you are interested in covering. >> >> So far the agenda is: >> >> - Direction of QEMU and toolstack in light of Google Cloud blog: >> https://cloudplatform.googleblog.com/2017/01/7-ways-we-harden-our-KVM-hypervisor-at-Google-Cloud-security-in-plaintext.html > > > Ah, I'd forgotten that this was on the call agenda. I actually > had an interesting conversation with Alex Graf last week about > some similar topics, which I guess you could generally summarize > as "what are the issues we need to address as a project in order > to not become irrelevant in five years time". Since I wrote them > up for an internal "what I did on my holi^Wconference trip" report > I might as well repost them here: > > - on the "VM support" side, QEMU is more used because it's the only > production-quality option in this space, rather than because its > users love it. (cf the Google choice to replace it.) It's also got > a pretty poor security record. It wouldn't be too surprising if > some time in the next five years somebody writes a replacement in > a safer language (perhaps also targeting only the VM support role) > and it got enough mindshare and takeup to eclipse QEMU. > [Is it too early/daft to think about prototyping being able to > write QEMU device emulation in Rust ?] I think rust has the potential to be very interesting. I've been watching to remacs project with interest: https://github.com/Wilfred/remacs They are attempting to port Emacs to rust in a piecemeal way. Whether this works remains to be seen but it is certainly an interesting approach compared to other "re-write it all" approaches. > If the "VM support" usecase moves to another project then QEMU > will become a very quiet backwater... > - on the "emulation" side, nobody is clearly articulating a purpose > for QEMU, a reason why you should use it rather than other modelling > technologies (or rather than using real hardware). As a result the > efforts applied to QEMU are somewhat unfocused. Are we trying to be: > . a dev platform before easy h/w availability? > [not easy for QEMU for several reasons] > . a dev tool that provides better introspection into guest > behaviour than running on h/w? > [if so we should put more work into improving our introspection > and guest tracing capabilities!] For example now we support atomics in the TCG it would be fairly easy* to port something like the ThreadSanitizer (which has fairly hefty memory requirements) as a tool for debugging system code. > . primarily a tool for doing automated CI testing and one-off > developer smoke-testing that's easier to set up and scale than > trying to test on real h/w? > . something else? > [your idea goes here!] > - in all areas our legacy code and back-compatibility requirements > are threatening to choke forward progress if we don't make serious > efforts to get on top of them > - there's no easy way for people to use parts of QEMU like the CPU > emulation, or to add their own devices without having to write lots > of C code (we're firmly in a "one monolithic blob of code" setup > right now and disentangling and setting clear API dividing lines > will be a lot of work) I spoke to Edgar about posting his rports patch set as a catalyst for discussion. Certainly for modelling hobby projects or new hardware QEMU could do with support for rapid prototyping. Others have mentioned maybe including a scripting language integration for device modelling - although I still hold the view that what ever language you choose will be the "wrong one" according to the majority of developers. > [Making QEMU more modular would help with defeating the legacy > and back-compat dragons, though] > > thanks > -- PMM -- Alex Bennée