[Qemu-devel] [PATCH 02/10] s390x/cpumodel: remove CSSKE from base model

[Christian Borntraeger]

conditional sske is deprecated and a distant future machine (will be one
where the IBC will not allow to fully go back to z14) will remove this
feature. To prepare for this and allow for the z14 and older cpu model
to still run on systems without csske, remove csske from the base (and
thus the default models for z10..z14). For compat machines we have to
add those back.

Signed-off-by: Christian Borntraeger <address@hidden>
---
 hw/s390x/s390-virtio-ccw.c  |  2 ++
 target/s390x/cpu_models.c   | 21 +++++++++++++++++++++
 target/s390x/cpu_models.h   |  1 +
 target/s390x/gen-features.c |  1 -
 4 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index d11069b860..3415948b2c 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -648,6 +648,8 @@ bool css_migration_enabled(void)
 
 static void ccw_machine_4_0_instance_options(MachineState *machine)
 {
+    /* re-enable csske for compat machines in the base model */
+    s390_cpumodel_fixup_csske();
 }
 
 static void ccw_machine_4_0_class_options(MachineClass *mc)
diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
index eb125d4d0d..4e5aa879f3 100644
--- a/target/s390x/cpu_models.c
+++ b/target/s390x/cpu_models.c
@@ -93,6 +93,27 @@ static S390FeatBitmap qemu_max_cpu_feat;
 /* features part of a base model but not relevant for finding a base model */
 S390FeatBitmap ignored_base_feat;
 
+/*
+ * We removed CSSKE from the base features. This is a hook for compat machines
+ * to put this back for gen10..gen14. As the base model is also part of the
+ * default model to have to fixup both bitfields
+ */
+void s390_cpumodel_fixup_csske(void)
+{
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(s390_cpu_defs); i++) {
+        const S390CPUDef *def = &s390_cpu_defs[i];
+
+        if (def->gen < 10 || def->gen > 14) {
+            continue;
+        }
+
+        set_bit(S390_FEAT_CONDITIONAL_SSKE, (unsigned long *)&def->base_feat);
+        set_bit(S390_FEAT_CONDITIONAL_SSKE, (unsigned long 
*)&def->default_feat);
+    }
+}
+
 void s390_cpudef_featoff(uint8_t gen, uint8_t ec_ga, S390Feat feat)
 {
     const S390CPUDef *def;
diff --git a/target/s390x/cpu_models.h b/target/s390x/cpu_models.h
index 174a99e561..b2e37bc8cf 100644
--- a/target/s390x/cpu_models.h
+++ b/target/s390x/cpu_models.h
@@ -73,6 +73,7 @@ struct S390CPUModel {
 #define ibc_gen(x)        (x == 0 ? 0 : ((x >> 4) + S390_GEN_Z10))
 #define ibc_ec_ga(x)      (x & 0xf)
 
+void s390_cpumodel_fixup_csske(void);
 void s390_cpudef_featoff(uint8_t gen, uint8_t ec_ga, S390Feat feat);
 void s390_cpudef_featoff_greater(uint8_t gen, uint8_t ec_ga, S390Feat feat);
 void s390_cpudef_group_featoff_greater(uint8_t gen, uint8_t ec_ga,
diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c
index e4739a6b9f..bea2f80c49 100644
--- a/target/s390x/gen-features.c
+++ b/target/s390x/gen-features.c
@@ -301,7 +301,6 @@ static uint16_t base_GEN9_GA1[] = {
 #define base_GEN9_GA3 EmptyFeat
 
 static uint16_t base_GEN10_GA1[] = {
-    S390_FEAT_CONDITIONAL_SSKE,
     S390_FEAT_PARSING_ENH,
     S390_FEAT_MOVE_WITH_OPTIONAL_SPEC,
     S390_FEAT_EXTRACT_CPU_TIME,
-- 
2.19.1