[PATCH v19 06/21] s390x/cpu topology: interception of PTF instruction

[Pierre Morel <pmorel@linux.ibm.com>]

When the host supports the CPU topology facility, the PTF
instruction with function code 2 is interpreted by the SIE,
provided that the userland hypervisor activates the interpretation
by using the KVM_CAP_S390_CPU_TOPOLOGY KVM extension.

The PTF instructions with function code 0 and 1 are intercepted
and must be emulated by the userland hypervisor.

During RESET all CPU of the configuration are placed in
horizontal polarity.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
 include/hw/s390x/s390-virtio-ccw.h |  6 ++++
 hw/s390x/cpu-topology.c            | 56 ++++++++++++++++++++++++++++--
 target/s390x/kvm/kvm.c             | 11 ++++++
 3 files changed, 71 insertions(+), 2 deletions(-)

diff --git a/include/hw/s390x/s390-virtio-ccw.h b/include/hw/s390x/s390-virtio-ccw.h
index ea10a6c6e1..9aa9f48bd0 100644
--- a/include/hw/s390x/s390-virtio-ccw.h
+++ b/include/hw/s390x/s390-virtio-ccw.h
@@ -31,6 +31,12 @@ struct S390CcwMachineState {
     bool vertical_polarization;
 };
 
+#define S390_PTF_REASON_NONE (0x00 << 8)
+#define S390_PTF_REASON_DONE (0x01 << 8)
+#define S390_PTF_REASON_BUSY (0x02 << 8)
+#define S390_TOPO_FC_MASK 0xffUL
+void s390_handle_ptf(S390CPU *cpu, uint8_t r1, uintptr_t ra);
+
 struct S390CcwMachineClass {
     /*< private >*/
     MachineClass parent_class;
diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
index 1d672d4d81..eec6c9a896 100644
--- a/hw/s390x/cpu-topology.c
+++ b/hw/s390x/cpu-topology.c
@@ -26,8 +26,6 @@
  * .smp: keeps track of the machine topology.
  * .list: queue the topology entries inside which
  *        we keep the information on the CPU topology.
- * .polarization: the current subsystem polarization
- *
  */
 S390Topology s390_topology = {
     /* will be initialized after the cpu model is realized */
@@ -86,6 +84,57 @@ static void s390_topology_init(MachineState *ms)
     QTAILQ_INSERT_HEAD(&s390_topology.list, entry, next);
 }
 
+/*
+ * s390_handle_ptf:
+ *
+ * @register 1: contains the function code
+ *
+ * Function codes 0 (horizontal) and 1 (vertical) define the CPU
+ * polarization requested by the guest.
+ *
+ * Function code 2 is handling topology changes and is interpreted
+ * by the SIE.
+ */
+void s390_handle_ptf(S390CPU *cpu, uint8_t r1, uintptr_t ra)
+{
+    struct S390CcwMachineState *s390ms = S390_CCW_MACHINE(current_machine);
+    CPUS390XState *env = &cpu->env;
+    uint64_t reg = env->regs[r1];
+    int fc = reg & S390_TOPO_FC_MASK;
+
+    if (!s390_has_feat(S390_FEAT_CONFIGURATION_TOPOLOGY)) {
+        s390_program_interrupt(env, PGM_OPERATION, ra);
+        return;
+    }
+
+    if (env->psw.mask & PSW_MASK_PSTATE) {
+        s390_program_interrupt(env, PGM_PRIVILEGED, ra);
+        return;
+    }
+
+    if (reg & ~S390_TOPO_FC_MASK) {
+        s390_program_interrupt(env, PGM_SPECIFICATION, ra);
+        return;
+    }
+
+    switch (fc) {
+    case S390_CPU_POLARIZATION_VERTICAL:
+    case S390_CPU_POLARIZATION_HORIZONTAL:
+        if (s390ms->vertical_polarization == !!fc) {
+            env->regs[r1] |= S390_PTF_REASON_DONE;
+            setcc(cpu, 2);
+        } else {
+            s390ms->vertical_polarization = !!fc;
+            s390_cpu_topology_set_changed(true);
+            setcc(cpu, 0);
+        }
+        break;
+    default:
+        /* Note that fc == 2 is interpreted by the SIE */
+        s390_program_interrupt(env, PGM_SPECIFICATION, ra);
+    }
+}
+
 /**
  * s390_topology_reset:
  *
@@ -94,7 +143,10 @@ static void s390_topology_init(MachineState *ms)
  */
 void s390_topology_reset(void)
 {
+    struct S390CcwMachineState *s390ms = S390_CCW_MACHINE(current_machine);
+
     s390_cpu_topology_set_changed(false);
+    s390ms->vertical_polarization = false;
 }
 
 /**
diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
index bc953151ce..fb63be41b7 100644
--- a/target/s390x/kvm/kvm.c
+++ b/target/s390x/kvm/kvm.c
@@ -96,6 +96,7 @@
 
 #define PRIV_B9_EQBS                    0x9c
 #define PRIV_B9_CLP                     0xa0
+#define PRIV_B9_PTF                     0xa2
 #define PRIV_B9_PCISTG                  0xd0
 #define PRIV_B9_PCILG                   0xd2
 #define PRIV_B9_RPCIT                   0xd3
@@ -1464,6 +1465,13 @@ static int kvm_mpcifc_service_call(S390CPU *cpu, struct kvm_run *run)
     }
 }
 
+static void kvm_handle_ptf(S390CPU *cpu, struct kvm_run *run)
+{
+    uint8_t r1 = (run->s390_sieic.ipb >> 20) & 0x0f;
+
+    s390_handle_ptf(cpu, r1, RA_IGNORED);
+}
+
 static int handle_b9(S390CPU *cpu, struct kvm_run *run, uint8_t ipa1)
 {
     int r = 0;
@@ -1481,6 +1489,9 @@ static int handle_b9(S390CPU *cpu, struct kvm_run *run, uint8_t ipa1)
     case PRIV_B9_RPCIT:
         r = kvm_rpcit_service_call(cpu, run);
         break;
+    case PRIV_B9_PTF:
+        kvm_handle_ptf(cpu, run);
+        break;
     case PRIV_B9_EQBS:
         /* just inject exception */
         r = -1;
-- 
2.31.1