On Wed, Sep 24, 2025 at 5:51 AM Stefan Hajnoczi <[email protected]> wrote: > > On Wed, Sep 24, 2025 at 01:38:31PM +0200, David Hildenbrand wrote: > > > > > > > > Two more points: > > > > > > > > 1) Security lockdown. Security lockdown transforms multikernel from > > > > "0-day means total compromise" to "0-day means single workload > > > > compromise with rapid recovery." This is still a significant improvement > > > > over containers where a single kernel 0-day compromises everything > > > > simultaneously. > > > > > > I don't follow. My understanding is that multikernel currently does not > > > prevent spawned kernels from affecting each other, so a kernel 0-day in > > > multikernel still compromises everything? > > > > I would assume that if there is no enforced isolation by the hardware (e.g., > > virtualization, including partitioning hypervisors like jailhouse, pkvm etc) > > nothing would stop a kernel A to access memory assigned to kernel B. > > > > And of course, memory is just one of the resources that would not be > > properly isolated. > > > > Not sure if encrypting memory per kernel would really allow to not let other > > kernels still damage such kernels. > > > > Also, what stops a kernel to just reboot the whole machine? Happy to learn > > how that will be handled such that there is proper isolation. > > The reason I've been asking about the fault isolation and security > statements in the cover letter is because it's unclear: > 1. What is implemented today in multikernel. > 2. What is on the roadmap for multikernel. > 3. What is out of scope for multikernel. > > Cong: Can you clarify this? If the answer is that fault isolation and > security are out of scope, then this discussion can be skipped.
It is my pleasure. The email is too narrow, therefore I wrote a complete document for you: https://docs.google.com/document/d/1yneO6O6C_z0Lh3A2QyT8XsH7ZrQ7-naGQT-rpdjWa_g/edit?usp=sharing I hope it answers all of the above questions and provides a clear big picture. If not, please let me know. (If you need edit permission for the above document, please just request, I will approve.) Regards, Cong Wang
