[PATCH] 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")
---

If you're sure that this is what you want, then I'll send a v2 of the
patch set.

---
 target/s390x/cpu_features.c | 5 +++++
 target/s390x/cpu_features.h | 4 ++++
 target/s390x/cpu_models.c   | 4 ++++
 target/s390x/kvm.c          | 3 +--
 4 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/target/s390x/cpu_features.c b/target/s390x/cpu_features.c
index 31ea8df246..42fe0bf4ca 100644
--- a/target/s390x/cpu_features.c
+++ b/target/s390x/cpu_features.c
@@ -14,6 +14,7 @@
 #include "qemu/osdep.h"
 #include "qemu/module.h"
 #include "cpu_features.h"
+#include "hw/s390x/pv.h"
 
 #define DEF_FEAT(_FEAT, _NAME, _TYPE, _BIT, _DESC) \
     [S390_FEAT_##_FEAT] = {                        \
@@ -105,6 +106,10 @@ void s390_fill_feat_block(const S390FeatBitmap features, S390FeatType type,
         }
         feat = find_next_bit(features, S390_FEAT_MAX, feat + 1);
     }
+
+    if (type == S390_FEAT_TYPE_SCLP_FAC134 && s390_is_pv()) {
+        clear_be_bit(s390_feat_def(S390_FEAT_DIAG_318)->bit, data);
+    }
 }
 
 void s390_add_from_feat_block(S390FeatBitmap features, S390FeatType type,
diff --git a/target/s390x/cpu_features.h b/target/s390x/cpu_features.h
index ef52ffce83..87463f064d 100644
--- a/target/s390x/cpu_features.h
+++ b/target/s390x/cpu_features.h
@@ -81,6 +81,10 @@ const S390FeatGroupDef *s390_feat_group_def(S390FeatGroup group);
 
 #define BE_BIT_NR(BIT) (BIT ^ (BITS_PER_LONG - 1))
 
+static inline void clear_be_bit(unsigned int bit_nr, uint8_t *array)
+{
+    array[bit_nr / 8] &= ~(0x80 >> (bit_nr % 8));
+}
 static inline void set_be_bit(unsigned int bit_nr, uint8_t *array)
 {
     array[bit_nr / 8] |= 0x80 >> (bit_nr % 8);
diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
index ca484bfda7..461e0b8f4a 100644
--- a/target/s390x/cpu_models.c
+++ b/target/s390x/cpu_models.c
@@ -29,6 +29,7 @@
 #include "hw/pci/pci.h"
 #endif
 #include "qapi/qapi-commands-machine-target.h"
+#include "hw/s390x/pv.h"
 
 #define CPUDEF_INIT(_type, _gen, _ec_ga, _mha_pow, _hmfai, _name, _desc) \
     {                                                                    \
@@ -238,6 +239,9 @@ bool s390_has_feat(S390Feat feat)
         }
         return 0;
     }
+    if (feat == S390_FEAT_DIAG_318 && s390_is_pv()) {
+        return false;
+    }
     return test_bit(feat, cpu->model->features);
 }
 
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