Re: [patch 1/2] x86_64 page fault NMI-safe

H. Peter Anvin
2010-07-15T23:21:22Z

On 07/15/2010 03:58 PM, Andi Kleen wrote:
>> Why do we force IST use for NMI, btw? Maybe we shouldn't, and just use
>> the normal kernel stack mechanisms?
>
> If you don't use IST the SYSCALL entry is racy during the window
> when RSP is not set up yet (same for MCE etc.)
>

Right, the kernel stack is not ready.

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.