Messages in this thread | | | Date | Mon, 29 Feb 2016 19:20:47 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH 0/4] MSR: MSR: MSR Whitelist and Batch Introduction |
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On Mon, Feb 29, 2016 at 12:53:18PM -0500, George Spelvin wrote: > I worry that this is this too ambitious a goal. Who is volunteering > to actually do this?
From a quick look, the stuff in the examples was already in the rapl driver.
> It takes quite a while to find a good OS-level abstraction (remember > wakelocks?), and MSRs are the CPU architect's equivalent of ioctls. > So they're a bit of a mess, and there will keep being new ones.
And yet you end up needing only a handful in most cases.
> I agree with you about anything that's going to see widespread use, but > for specialized (apparently mostly HPC) use where the application really > is heavily optimized for specific CPU models, perhaps dangerous-but-simple > is good enough?
If it is that specialized, then it doesn't belong upstream.
> The proposed interface is simple and imposes very little maintenance > burden on the kernel. My main objection is that it's yet another > special-case permission system. Are we *sure* we'll never want to have > to classes of users with different access rights?
The proposed interface is the wrong thing to do. There's no need to talk about how simple and less of a burden it is.
The burden comes when people start complaining about strange issues and we go and have to get a full MSR dump at the time the explosion happens because some userspace tool went nuts and scribbled all over them. No one wants to be on the receiving end of a bug report like this.
-- Regards/Gruss, Boris.
ECO tip #101: Trim your mails when you reply.
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