Re: [PATCH] x86/fred: Send an EVENT_CHECK IPI on exit from NMI

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

On 6/24/26 4:23 PM, Andrew Cooper wrote:
> Returning from an NMI which hits guest context needs special casing in FRED
> mode just like it does in IDT mode.
>
> Break nmi_exit_to_guest() out of handle_ist_exception(), and use it in
> entry_FRED_R3() also.
>
> Expand the comment a little, and invert the conditional jump to
> compat_restore_all_guest() to avoid needing an #else clause for CONFIG_PV32.
>
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> ---
> CC: Jan Beulich <jbeulich@xxxxxxxx>
> CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> CC: Teddy Astie <teddy.astie@xxxxxxxxxx>
> CC: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
>
> Slightly RFC, not tested yet.  (My AMD system takes an eternity to reboot)
I would like to have a test on hardware to verify that it doesn't break 
something else. With that:
> For 4.22.  Found during testing of FRED.  The consqeuence is that we can end
> up scheduling while still in NMI context, after which things like the watchdog
> and other diagnostics don't work properly.
> ---
 Relase-Acked-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>

Thanks.

~ Oleksii