On 22/05/19 14:53, Stefan Hajnoczi wrote: > On Tue, May 21, 2019 at 03:39:40PM +0100, Peter Maydell wrote: >> Hi; I have on my todo list the idea of some experimentation/prototyping >> of whether being able to write some components of QEMU in Rust would >> be (a) feasible (b) beneficial (c) fun to play around with even if >> it is likely that it doesn't go anywhere :-) >> >> I know Paolo has had a look at how you might write some makefiles >> to integrate rust into a C program (https://github.com/bonzini/rust-and-c/). >> Has anybody else been doing anything in this general area ? >> >> (I went to two good talks locally recently about rust-vmm and Amazon's >> 'firecracker' VMM by Andreea Florescu and Diana Popa -- I >> definitely plan to look at rust-vmm as part of this.) > > There are some in-development vhost-user device backends in Rust. > Sergio Lopez is working on a vhost-user-blk implementation. David > Gilbert is working on a vhost-user-fs implementation. > > I think mixing Rust and C code in the main QEMU binary itself is > probably more trouble than it's worth. Think boilerplate, duplication, > coming up with safe Rust APIs for QEMU's unsafe APIs.
This is true. The case I was playing with is where the QEMU APIs have a more or less direct mapping to rust-vmm APIs and only have a limited number of dependencies on other C APIs. This way, you can either write a Rust binding to the C code, or rewrite the C code in Rust with tiny C wrapper APIs on top. For example, the memory API (more or less) depends only on RCU and maps to rust-vmm/vm-memory, and virtqueue processing in rust-vmm/vm-virtio depends only on the memory API. Thanks, Paolo > I'm more interested in using Rust for separate processes that can be > written from scratch. > > Stefan >
