KVM: perform an invalid memslot step for gpa base change

commit 12d6e7538e2d418c08f082b1b44ffa5fb7270ed8 upstream.

PPC must flush all translations before the new memory slot
is visible.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index bfa8e1e..a311660 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -774,7 +774,7 @@ skip_lpage:
                new.userspace_addr = mem->userspace_addr;
 #endif /* not defined CONFIG_S390 */
 
-       if (!npages) {
+       if (!npages || base_gfn != old.base_gfn) {
                r = -ENOMEM;
                slots = kzalloc(sizeof(struct kvm_memslots), GFP_KERNEL);
                if (!slots)
@@ -788,8 +788,8 @@ skip_lpage:
                old_memslots = kvm->memslots;
                rcu_assign_pointer(kvm->memslots, slots);
                synchronize_srcu_expedited(&kvm->srcu);
-               /* From this point no new shadow pages pointing to a deleted
-                * memslot will be created.
+               /* From this point no new shadow pages pointing to a deleted,
+                * or moved, memslot will be created.
                 *
                 * validation of sp->gfn happens in:
                 *      - gfn_to_hva (kvm_read_guest, gfn_to_pfn)