On Thu, 8 Feb 2018 10:42:41 +0100 Laurent Vivier <lviv...@redhat.com> wrote:
> We ignore silently the value of smp_threads when we set > the default VSMT value, and if smp_threads is greater than VSMT > kernel is going into trouble later. > > Fixes: 8904e5a750 > ("spapr: Adjust default VSMT value for better migration compatibility") > > Signed-off-by: Laurent Vivier <lviv...@redhat.com> > --- > Reviewed-by: Greg Kurz <gr...@kaod.org> > Notes: > v2: display a specific error message when the default VSMT is used > fix subject > > hw/ppc/spapr.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index 32a876be56..11de276cd5 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -2311,6 +2311,12 @@ static void spapr_set_vsmt_mode(sPAPRMachineState > *spapr, Error **errp) > * overwhelmingly common case in production systems. > */ > spapr->vsmt = 8; > + if (spapr->vsmt < smp_threads) { > + error_setg(&local_err, "Cannot support %d threads/core" > + " because it must be <= to default VSMT mode (%d)", > + smp_threads, spapr->vsmt); > + goto out; > + } > } > > /* KVM: If necessary, set the SMT mode: */