[S390] kvm guest address space mapping

Add code that allows KVM to control the virtual memory layout that
is seen by a guest. The guest address space uses a second page table
that shares the last level pte-tables with the process page table.
If a page is unmapped from the process page table it is automatically
unmapped from the guest page table as well.

The guest address space mapping starts out empty, KVM can map any
individual 1MB segments from the process virtual memory to any 1MB
aligned location in the guest virtual memory. If a target segment in
the process virtual memory does not exist or is unmapped while a
guest mapping exists the desired target address is stored as an
invalid segment table entry in the guest page table.
The population of the guest page table is fault driven.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/s390/include/asm/mmu.h b/arch/s390/include/asm/mmu.h
index 82d0847896a0..4506791adcd5 100644
--- a/arch/s390/include/asm/mmu.h
+++ b/arch/s390/include/asm/mmu.h
@@ -6,6 +6,7 @@ typedef struct {
         unsigned int flush_mm;
         spinlock_t list_lock;
         struct list_head pgtable_list;
+        struct list_head gmap_list;
         unsigned long asce_bits;
         unsigned long asce_limit;
         unsigned long vdso_base;
@@ -17,6 +18,7 @@ typedef struct {
 
 #define INIT_MM_CONTEXT(name)                                                 \
         .context.list_lock    = __SPIN_LOCK_UNLOCKED(name.context.list_lock), \
-        .context.pgtable_list = LIST_HEAD_INIT(name.context.pgtable_list),
+        .context.pgtable_list = LIST_HEAD_INIT(name.context.pgtable_list),    \
+        .context.gmap_list = LIST_HEAD_INIT(name.context.gmap_list),
 
 #endif