Re: [patch V6 15/37] x86/entry: Change exit path of xen_failsafe_callback

[Andy Lutomirski]

On Fri, May 15, 2020 at 5:10 PM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
>
> xen_failsafe_callback is invoked from XEN for two cases:
>
>   1. Fault while reloading DS, ES, FS or GS
>   2. Fault while executing IRET
>
> #1 retries the IRET after XEN has fixed up the segments.
> #2 injects a #GP which kills the task
>
> For #1 there is no reason to go through the full exception return path
> because the tasks TIF state is still the same. So just going straight to
> the IRET path is good enough.

Seems reasonable:

Acked-by: Andy Lutomirski <luto@xxxxxxxxxx>

Although a look from a Xen person might be nice too.