On Thu, Dec 19, 2024 at 09:30:16PM +0100, Paolo Bonzini wrote: > On Thu, Dec 19, 2024 at 7:09 PM Keith Busch <kbusch@xxxxxxxxxx> wrote: > > > Is crosvm trying to do anything but exec? If not, it should probably use the > > > flag. > > > > Good point, and I'm not sure right now. I don't think I know any crosvm > > developer experts but I'm working on that to get a better explanation of > > what's happening, > > Ok, I found the code and it doesn't exec (e.g. > https://github.com/google/crosvm/blob/b339d3d7/src/crosvm/sys/linux/jail_warden.rs#L122), > so that's not an option. Thanks, I was slowly getting there too. It's been a while since I had to work with the languange, so I'm a bit rusty (no pun intended) at navigating. > Well, if I understand correctly from a > cursory look at the code, crosvm is creating a jailed child process > early, and then spawns further jails through it; so it's just this > first process that has to cheat. > > One possibility on the KVM side is to delay creating the vhost_task > until the first KVM_RUN. I don't like it but... > > I think we should nevertheless add something to the status file in > procfs, that makes it easy to detect kernel tasks (PF_KTHREAD | > PF_IO_WORKER | PF_USER_WORKER). I currently think excluding kernel tasks from this check probably aligns with what it's trying to do, so anything to make that easier is a good step, IMO.
