Re: [PULL 10/30] ppc/spapr: H_ENTER_NESTED should restore host XER ca field

[Cédric Le Goater]

On 6/26/23 14:26, Michael Tokarev wrote:
> 26.06.2023 08:56, Cédric Le Goater wrote:
> > From: Nicholas Piggin <npiggin@gmail.com>
> >
> > Fix missing env->ca restore when going from L2 back to the host.
> >
> > Fixes: 120f738a467 ("spapr: implement nested-hv capability for the virtual 
> > hypervisor")
> > Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
> > Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> > Signed-off-by: Cédric Le Goater <clg@kaod.org>
> > ---
> >   hw/ppc/spapr_hcall.c | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> > index b9047555757f..0582b524d108 100644
> > --- a/hw/ppc/spapr_hcall.c
> > +++ b/hw/ppc/spapr_hcall.c
> > @@ -1773,6 +1773,7 @@ out_restore_l1:
> >       env->cfar = spapr_cpu->nested_host_state->cfar;
> >       env->xer = spapr_cpu->nested_host_state->xer;
> >       env->so = spapr_cpu->nested_host_state->so;
> > +    env->ca = spapr_cpu->nested_host_state->ca;
> >       env->ov = spapr_cpu->nested_host_state->ov;
> >       env->ov32 = spapr_cpu->nested_host_state->ov32;
> >       env->ca32 = spapr_cpu->nested_host_state->ca32;
>
> Is it -stable material too, or don't bother?
> 120f738a467 is 7.0.

I would say so. The CPU is missing state (Carry bit) when restoring context,
it could be important for some instructions.

Nick, did you have specific test case ?

Thanks,

C.