On Thu, 12 Jul 2018 09:23:01 +0200
David Hildenbrand <david@xxxxxxxxxx> wrote:
>
> > #include <linux/kernel.h>
> > @@ -589,8 +591,8 @@ int __gmap_link(struct gmap *gmap, unsigned
> > long gaddr, unsigned long vmaddr) return -EFAULT;
> > pmd = pmd_offset(pud, vmaddr);
> > VM_BUG_ON(pmd_none(*pmd));
> > - /* large pmds cannot yet be handled */
> > - if (pmd_large(*pmd))
> > + /* Are we allowed to use huge pages? */
> > + if (pmd_large(*pmd) && !gmap->mm->context.uses_gmap_hpage)
> > return -EFAULT;
> > /* Link gmap segment table entry location to page table. */
> > rc = radix_tree_preload(GFP_KERNEL);
> > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> > index b6270a3b38e9..b955b986b341 100644
> > --- a/include/uapi/linux/kvm.h
> > +++ b/include/uapi/linux/kvm.h
> > @@ -949,6 +949,7 @@ struct kvm_ppc_resize_hpt {
> > #define KVM_CAP_GET_MSR_FEATURES 153
> > #define KVM_CAP_HYPERV_EVENTFD 154
> > #define KVM_CAP_HYPERV_TLBFLUSH 155
> > +#define KVM_CAP_S390_HPAGE_1M 156
> >
> > #ifdef KVM_CAP_IRQ_ROUTING
> >
> >
>
> I was wondering if we should add some safety net for gmap shadows when
> hitting a huge pmd. Or when trying to create a shadow for a gmap with
> huge pmds enabled (add a check in gmap_shadow()). So the GMAP kernel
> interface remains consistent.
For now we don't have the sief2 so we don't end up in gmap_shadow()
anyway. Huge l3 in small l2 is currently supported via the fake tables.
So what do you want to keep consistent?
>
>
> Apart from that, looks good to me!
>
