From: "Daniel P. Berrangé" <berrange@redhat.com>
To: Sergio Lopez <slp@redhat.com>
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
"Stefan Hajnoczi" <stefanha@gmail.com>,
qemu-devel <qemu-devel@nongnu.org>,
"Markus Armbruster" <armbru@redhat.com>,
"Oleinik, Alexander" <alxndr@bu.edu>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Alex Bennée" <alex.bennee@linaro.org>,
"Dave Gilbert" <dgilbert@redhat.com>
Subject: Re: Why QEMU should move from C to Rust (clickbait alert ;))
Date: Thu, 6 Aug 2020 14:43:03 +0100 [thread overview]
Message-ID: <20200806134303.GM4159383@redhat.com> (raw)
In-Reply-To: <20200806133845.maouiwnazkjtpklr@mhamilton>
On Thu, Aug 06, 2020 at 03:38:45PM +0200, Sergio Lopez wrote:
> On Thu, Aug 06, 2020 at 01:01:30PM +0100, Daniel P. Berrangé wrote:
> > On Thu, Aug 06, 2020 at 01:51:48PM +0200, Sergio Lopez wrote:
> > > On Thu, Aug 06, 2020 at 11:24:13AM +0100, Stefan Hajnoczi wrote:
> > > <snip>
> > > > Conclusion
> > > > ---------------
> > > > Most security bugs in QEMU today are C programming bugs. Switching to
> > > > a safer programming language will significantly reduce security bugs
> > > > in QEMU. Rust is now mature and proven enough to use as the language
> > > > for device emulation code. Thanks to vhost-user and vfio-user using
> > > > Rust for device emulation does not require a big conversion of QEMU
> > > > code, it can simply be done in a separate program. This way attack
> > > > surfaces can be written in Rust to make them less susceptible to
> > > > security bugs going forward.
> > > >
> > >
> > > Having worked on Rust implementations for vhost-user-fs and
> > > vhost-user-blk, I'm 100% sold on this idea.
> > >
> > > That said, there are a couple things that I think may help getting
> > > more people into implementing vhost-user devices in Rust.
> > >
> > > 1. Having a reference implementation for a simple device somewhere
> > > close or inside the QEMU source tree. I'd say vhost-user-blk is a
> > > clear candidate, given that a naive implementation for raw files
> > > without any I/O optimization is quite easy to read and understand.
> > >
> > > 2. Integrating the ability to start-up vhost-user daemons from QEMU,
> > > in an easy and portable way. I know we can always rely on daemons
> > > like libvirt to do this for us, but I think it'd be nicer to be able
> > > to define a vhost-user device from the command line and have QEMU
> > > execute it with the proper parameters (BTW, Cloud-Hypervisor already
> > > does that). This would probably require some kind of configuration
> > > file, to be able to define which binary provides each vhost-user
> > > device personality, but could also be a way for "sanctioning"
> > > daemons (through the configuration defaults), and to have them adhere
> > > to a standardized command line format.
> >
> > This second point is such a good idea that we already have defined
> > how todo this in QEMU - see the docs/interop/vhost-user.json file.
> > This specifies metadata files that should be installed into a
> > defined location such that QEMU/libvirt/other mgmt app can locate
> > vhost-user impls for each type of device, and priortize between
> > different impls.
>
> Nice, but AFAIK QEMU still lacks the ability to process those files
> and run the vhost-user device providers by itself. Or perhaps I just
> can't find it (?).
You're correct, thus far QEMU merely defined the standard, but thus
far libvirt is the only consumer I know of that implemented it. It
was anticipated that QEMU would implement support too but no one
has attempted it to my knowledge.
Regards,
Daniel
--
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next prev parent reply other threads:[~2020-08-06 13:43 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-06 10:24 Why QEMU should move from C to Rust (clickbait alert ;)) Stefan Hajnoczi
2020-08-06 11:08 ` Daniel P. Berrangé
2020-08-06 13:39 ` Alex Bennée
2020-08-07 9:28 ` Stefan Hajnoczi
2020-08-07 9:44 ` Stefan Hajnoczi
2020-08-06 11:51 ` Sergio Lopez
2020-08-06 12:01 ` Daniel P. Berrangé
2020-08-06 13:38 ` Sergio Lopez
2020-08-06 13:43 ` Daniel P. Berrangé [this message]
2020-08-07 9:27 ` Stefan Hajnoczi
2020-08-07 9:45 ` Stefan Hajnoczi
2020-08-07 9:39 ` Stefan Hajnoczi
2020-08-21 20:18 Alex Carter
2020-08-27 8:08 ` Sergio Lopez
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