# Re: \[PATCH v5 3/6\] x86/sev-es: Split up runtime \#VC handler for correct state tracking

- From: Joerg Roedel \<joro@8bytes.org\>
- Date: 2021-06-16 19:01:36 
- List: virtualization
- Page: https://ratatoskr.run/virtualization/2021/06/1417077
- Thread: https://ratatoskr.run/linux-coco/2021/06/1413505/t.md

```text
Hi Peter,

sorry, missed this email before sending out v6.

On Wed, Jun 16, 2021 at 06:04:26PM +0200, Peter Zijlstra wrote:
> On Mon, Jun 14, 2021 at 03:53:24PM +0200, Joerg Roedel wrote:
> >  _ASM_NOKPROBE(\asmsym)
> >  SYM_CODE_END(\asmsym)
> 
> Consistency with idtentry_mce_db would seem to suggest using \cfunc and
> noist_\cfunc.
> 
> amluto, tglx: do we have strong feelings on consistency?

Yeah, but this distinction does not make sense here, as none of the #VC
handlers C functions run on the actual #VC IST stack. The from-kernel
function might run on the fall-back stack (not really possible today
unless the hypervisor does something nasty). And the difference between
the fall-back stack and the actual IST stack is, that on the fall-back
stack nesting #VC exceptions is still supported.

> > +	vc_handle_trap_db(regs);
> 
> It's a bit sad this does user_mode(regs) again.

Okay, I will change this according your comments.

Thanks,

	Joerg

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