s390/mm: support EDAT2 for gmap shadows

If the guest is enabled for EDAT2, we can easily create shadows for
guest2 -> guest3 provided tables that make use of EDAT2.

If guest2 references a 2GB page, this memory looks consecutive for guest2,
but it does not have to be so for us. Therefore we have to create fake
segment and page tables.

This works just like EDAT1 support, so page tables are removed when the
parent table (r3t table entry) is changed.

We don't hve to care about:
- ACCF-Validity Control in RTTE
- Access-Control Bits in RTTE
- Fetch-Protection Bit in RTTE
- Common-Region Bit in RTTE

Just like for EDAT1, all bits might be dropped and there is no guaranteed
that they are active.

Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/s390/include/asm/gmap.h b/arch/s390/include/asm/gmap.h
index c8ba5a197b1d..2e4c3b222a96 100644
--- a/arch/s390/include/asm/gmap.h
+++ b/arch/s390/include/asm/gmap.h
@@ -111,7 +111,8 @@ struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce,
 			 int edat_level);
 int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t);
 int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t);
-int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt);
+int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
+		    int fake);
 int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt,
 		    int fake);
 int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr,