Re: [PATCH v5 20/34] x86/fred: add a machine check entry stub for FRED

From: Peter Zijlstra
Date: Mon Mar 20 2023 - 12:11:32 EST


On Mon, Mar 06, 2023 at 06:39:32PM -0800, Xin Li wrote:
> Add a machine check entry stub for FRED.
>
> Unlike IDT, no need to save/restore dr7 in FRED machine check handler.

Given how fragile MCE is, the question should be, do we ever want hw
breakpoints to happen while it is running?

If the hw-breakpoint handler trips on the same memory fail that got us
into the mce the first time, we're dead.