Re: [patch V4 part 1 27/36] arm64: Prepare arch_nmi_enter() for recursion

[Frederic Weisbecker]

On Fri, May 15, 2020 at 11:29:13PM +0200, Thomas Gleixner wrote:
> Thomas Gleixner <tglx@xxxxxxxxxxxxx> writes:
> 
> > From: Frederic Weisbecker <frederic@xxxxxxxxxx>
> 
> This changelog was very empty. Here is what Peter provided:
> 
>  When using nmi_enter() recursively, arch_nmi_enter() must also be recursion
>  safe. In particular, it must be ensured that HCR_TGE is always set while in
>  NMI context when in HYP mode, and be restored to it's former state when
>  done.
> 
>  The current code fails this when interleaved wrong. Notably it overwrites
>  the original hcr state on nesting.
> 
>  Introduce a nesting counter to make sure to store the original value.

Nice!

Thanks.