KAISER: hiding the kernel from user space [LWN.net]

KAISER: hiding the kernel from user space

Posted Nov 16, 2017 4:57 UTC (Thu) by Cyberax (✭ supporter ✭, #52523)
Parent article: KAISER: hiding the kernel from user space

Can KAISER be made optional on process-level? Perhaps through a croup?

I would definitely like to protect my browser and anything started by it, but I would like my gcc started from a terminal to run at full speed.

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KAISER: hiding the kernel from user space

Posted Nov 16, 2017 20:40 UTC (Thu) by hansendc (subscriber, #7363) [Link] (1 responses)

Yes, this could be done, at least theoretically. But, the contexts where we have to decide to "do KAISER" or not are very tricky. We don't have a stack and don't have registers to clobber, so it's tricky to pull off.

You would essentially need to keep a bit of per-cpu data that was consulted very early in assembly at kernel entry. It would have to be updated at every context switch, probably from some flag in the task_struct. Again, doable, but far from trivial.

KAISER: hiding the kernel from user space

Posted Nov 19, 2017 6:16 UTC (Sun) by luto (subscriber, #39314) [Link]

It could be TIF_KAISER, no?

But this is definitely not a v1 feature.