kvm/ppc/booke: Hold srcu lock when calling gfn functions

KVM core expects arch code to acquire the srcu lock when calling
gfn_to_memslot and similar functions.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 1020119..ecbe908 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -832,6 +832,7 @@
 {
 	int r = RESUME_HOST;
 	int s;
+	int idx;
 
 	/* update before a new last_exit_type is rewritten */
 	kvmppc_update_timing_stats(vcpu);
@@ -1053,6 +1054,8 @@
 			break;
 		}
 
+		idx = srcu_read_lock(&vcpu->kvm->srcu);
+
 		gpaddr = kvmppc_mmu_xlate(vcpu, gtlb_index, eaddr);
 		gfn = gpaddr >> PAGE_SHIFT;
 
@@ -1075,6 +1078,7 @@
 			kvmppc_account_exit(vcpu, MMIO_EXITS);
 		}
 
+		srcu_read_unlock(&vcpu->kvm->srcu, idx);
 		break;
 	}
 
@@ -1098,6 +1102,8 @@
 
 		kvmppc_account_exit(vcpu, ITLB_VIRT_MISS_EXITS);
 
+		idx = srcu_read_lock(&vcpu->kvm->srcu);
+
 		gpaddr = kvmppc_mmu_xlate(vcpu, gtlb_index, eaddr);
 		gfn = gpaddr >> PAGE_SHIFT;
 
@@ -1114,6 +1120,7 @@
 			kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_MACHINE_CHECK);
 		}
 
+		srcu_read_unlock(&vcpu->kvm->srcu, idx);
 		break;
 	}