[PATCH 2/2] s390x: pv: Fix diag318 PV fencing

[Janosch Frank <frankja@linux.ibm.com>]

Diag318 fencing needs to be determined on the current VM PV state and
not on the state that the VM has when we create the CPU model.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Fixes: fabdada935 ("s390: guest support for diagnose 0x318")
Tested-by: Marc Hartmayer <mhartmay@linux.ibm.com>
---
 hw/s390x/sclp.c    | 10 ++++++++++
 target/s390x/kvm.c |  3 +--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
index 0cf2290826..69aba402d3 100644
--- a/hw/s390x/sclp.c
+++ b/hw/s390x/sclp.c
@@ -22,6 +22,7 @@
 #include "hw/s390x/event-facility.h"
 #include "hw/s390x/s390-pci-bus.h"
 #include "hw/s390x/ipl.h"
+#include "hw/s390x/pv.h"
 
 static inline SCLPDevice *get_sclp_device(void)
 {
@@ -142,6 +143,15 @@ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb)
     if (s390_has_feat(S390_FEAT_EXTENDED_LENGTH_SCCB)) {
         s390_get_feat_block(S390_FEAT_TYPE_SCLP_FAC134,
                             &read_info->fac134);
+        /*
+         * Diag318 is not available in protected mode and will result
+         * in an operation exception. As we can dynamically move in
+         * and out of protected mode, we need to fence the feature
+         * here rather than when creating the CPU model.
+         */
+        if (s390_is_pv()) {
+            read_info->fac134 &= ~0x80;
+        }
     }
 
     read_info->facilities = cpu_to_be64(SCLP_HAS_CPU_INFO |
diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index f13eff688c..baa070fdf7 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -2498,8 +2498,7 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, Error **errp)
      */
     set_bit(S390_FEAT_EXTENDED_LENGTH_SCCB, model->features);
 
-    /* DIAGNOSE 0x318 is not supported under protected virtualization */
-    if (!s390_is_pv() && kvm_check_extension(kvm_state, KVM_CAP_S390_DIAG318)) {
+    if (kvm_check_extension(kvm_state, KVM_CAP_S390_DIAG318)) {
         set_bit(S390_FEAT_DIAG_318, model->features);
     }
 
-- 
2.25.1