Tangential, but let's say I want to build a multiplayer game, where players (untrusted users) are allowed to run arbitrary code in some kind of a VM. I've so far established that:
- The VM has to be built in a safe and performant language (like Rust, Go, or - if careful - modern C++), and available as a library to integrate with the rest of the game. However I don't trust myself to write safe C/C++ (the game is being prototyped in LÖVE/Lua).
- Each VM instance needs a tight execution/instruction budget, to avoid stalling the server's main update loop; e.g. a timer/virtual "hardware interrupt", or simply counting cycles, or even something modelled after eBPF. The total number of VM instances running in a single game would also need to be limited somehow (e.g. making a key component scarce and/or non-renewable, or dividing the total instruction budget across all VMs, or requiring a player to be present in a nearby world chunk).
Use cases are something like redstone in Minecraft: curious and technically-inclined players could build contraptions, like auto-farming crops, pranks/traps, defences, fancy gates/moats, etc. Not the core of the gameplay, but rather one aspect of it, for the curious to explore, learn, have fun with.
There are many off-the-shelf VMs that do RISC-V or similar ISAs, and I'm considering picking one of those, but wondering if a RISC instruction set isn't too low-level for such a thing. On the other hand, it would be nice if the knowledge would be directly transferrable to the real world.
Anyone tried to build something similar and can share their experience?
- The VM has to be built in a safe and performant language (like Rust, Go, or - if careful - modern C++), and available as a library to integrate with the rest of the game. However I don't trust myself to write safe C/C++ (the game is being prototyped in LÖVE/Lua).
- Each VM instance needs a tight execution/instruction budget, to avoid stalling the server's main update loop; e.g. a timer/virtual "hardware interrupt", or simply counting cycles, or even something modelled after eBPF. The total number of VM instances running in a single game would also need to be limited somehow (e.g. making a key component scarce and/or non-renewable, or dividing the total instruction budget across all VMs, or requiring a player to be present in a nearby world chunk).
Use cases are something like redstone in Minecraft: curious and technically-inclined players could build contraptions, like auto-farming crops, pranks/traps, defences, fancy gates/moats, etc. Not the core of the gameplay, but rather one aspect of it, for the curious to explore, learn, have fun with.
There are many off-the-shelf VMs that do RISC-V or similar ISAs, and I'm considering picking one of those, but wondering if a RISC instruction set isn't too low-level for such a thing. On the other hand, it would be nice if the knowledge would be directly transferrable to the real world.
Anyone tried to build something similar and can share their experience?