x86/paravirt: Fix native_patch()

While chasing a regression I noticed we potentially patch the wrong
code in native_patch().

If we do not select the native code sequence, we must use the default
patcher, not fall-through the switch case.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Alok Kataria <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Chris Wright <[email protected]>
Cc: Jeremy Fitzhardinge <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Pan Xinhui <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Peter Anvin <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: kernel test robot <[email protected]>
Fixes: 3cded41794 ("x86/paravirt: Optimize native pv_lock_ops.vcpu_is_preempted()")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

arch/x86/kernel/paravirt_patch_32.c

@@ -58,15 +58,19 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
 				end   = end_pv_lock_ops_queued_spin_unlock;
 				goto patch_site;
 			}
+			goto patch_default;
+
 		case PARAVIRT_PATCH(pv_lock_ops.vcpu_is_preempted):
 			if (pv_is_native_vcpu_is_preempted()) {
 				start = start_pv_lock_ops_vcpu_is_preempted;
 				end   = end_pv_lock_ops_vcpu_is_preempted;
 				goto patch_site;
 			}
+			goto patch_default;
 #endif
 
 	default:
+patch_default:
 		ret = paravirt_patch_default(type, clobbers, ibuf, addr, len);
 		break;
 

arch/x86/kernel/paravirt_patch_64.c

@@ -70,15 +70,19 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
 				end   = end_pv_lock_ops_queued_spin_unlock;
 				goto patch_site;
 			}
+			goto patch_default;
+
 		case PARAVIRT_PATCH(pv_lock_ops.vcpu_is_preempted):
 			if (pv_is_native_vcpu_is_preempted()) {
 				start = start_pv_lock_ops_vcpu_is_preempted;
 				end   = end_pv_lock_ops_vcpu_is_preempted;
 				goto patch_site;
 			}
+			goto patch_default;
 #endif
 
 	default:
+patch_default:
 		ret = paravirt_patch_default(type, clobbers, ibuf, addr, len);
 		break;