[PATCH v15 06/11] 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 hypervizor 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 hypervizor.

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 ++
 target/s390x/cpu.h                 |   1 +
 hw/s390x/cpu-topology.c            | 103 +++++++++++++++++++++++++++++
 target/s390x/cpu-sysemu.c          |  14 ++++
 target/s390x/kvm/kvm.c             |  11 +++
 5 files changed, 135 insertions(+)

diff --git a/include/hw/s390x/s390-virtio-ccw.h b/include/hw/s390x/s390-virtio-ccw.h
index 9bba21a916..c1d46e78af 100644
--- a/include/hw/s390x/s390-virtio-ccw.h
+++ b/include/hw/s390x/s390-virtio-ccw.h
@@ -30,6 +30,12 @@ struct S390CcwMachineState {
     uint8_t loadparm[8];
 };
 
+#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/target/s390x/cpu.h b/target/s390x/cpu.h
index 848314d2a9..f6e207afde 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -857,6 +857,7 @@ void s390_enable_css_support(S390CPU *cpu);
 void s390_do_cpu_set_diag318(CPUState *cs, run_on_cpu_data arg);
 int s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch_id,
                                 int vq, bool assign);
+void s390_cpu_topology_set_modified(void);
 #ifndef CONFIG_USER_ONLY
 unsigned int s390_cpu_set_state(uint8_t cpu_state, S390CPU *cpu);
 #else
diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
index cf63f3dd01..1028bf4476 100644
--- a/hw/s390x/cpu-topology.c
+++ b/hw/s390x/cpu-topology.c
@@ -85,16 +85,104 @@ static void s390_topology_init(MachineState *ms)
     QTAILQ_INSERT_HEAD(&s390_topology.list, entry, next);
 }
 
+/**
+ * s390_topology_set_cpus_polarity:
+ * @polarity: polarity requested by the caller
+ *
+ * Set all CPU entitlement according to polarity and
+ * dedication.
+ * Default vertical entitlement is POLARITY_VERTICAL_MEDIUM as
+ * it does not require host modification of the CPU provisioning
+ * until the host decide to modify individual CPU provisioning
+ * using QAPI interface.
+ * However a dedicated vCPU will have a POLARITY_VERTICAL_HIGH
+ * entitlement.
+ */
+static void s390_topology_set_cpus_polarity(int polarity)
+{
+    CPUState *cs;
+
+    CPU_FOREACH(cs) {
+        if (polarity == POLARITY_HORIZONTAL) {
+            S390_CPU(cs)->env.entitlement = 0;
+        } else if (S390_CPU(cs)->env.dedicated) {
+            S390_CPU(cs)->env.entitlement = POLARITY_VERTICAL_HIGH;
+        } else {
+            S390_CPU(cs)->env.entitlement = POLARITY_VERTICAL_MEDIUM;
+        }
+    }
+}
+
+/*
+ * s390_handle_ptf:
+ *
+ * @register 1: contains the function code
+ *
+ * Function codes 0 (horizontal) and 1 (vertical) define the CPU
+ * polarization requested by the guest.
+ *
+ * Verify that the polarization really need to change and call
+ * s390_topology_set_cpus_polarity() specifying the requested polarity
+ * to set for all CPUs.
+ *
+ * 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)
+{
+    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 POLARITY_VERTICAL:
+    case POLARITY_HORIZONTAL:
+        if (s390_topology.polarity == fc) {
+            env->regs[r1] |= S390_PTF_REASON_DONE;
+            setcc(cpu, 2);
+        } else {
+            s390_topology.polarity = fc;
+            s390_cpu_topology_set_modified();
+            s390_topology_set_cpus_polarity(fc);
+            setcc(cpu, 0);
+        }
+        break;
+    default:
+        /* Note that fc == 2 is interpreted by the SIE */
+        s390_program_interrupt(env, PGM_SPECIFICATION, ra);
+    }
+}
+
 /**
  * s390_topology_reset:
  *
  * Generic reset for CPU topology, calls s390_topology_reset()
  * s390_topology_reset() to reset the kernel Modified Topology
  * change record.
+ * Then set global and all CPUs polarity to POLARITY_HORIZONTAL.
  */
 void s390_topology_reset(void)
 {
     s390_cpu_topology_reset();
+    /* Set global polarity to POLARITY_HORIZONTAL */
+    s390_topology.polarity = POLARITY_HORIZONTAL;
+    /* Set all CPU polarity to POLARITY_HORIZONTAL */
+    s390_topology_set_cpus_polarity(POLARITY_HORIZONTAL);
 }
 
 /**
@@ -137,6 +225,21 @@ static void s390_topology_cpu_default(S390CPU *cpu, Error **errp)
                           (smp->books * smp->sockets * smp->cores)) %
                          smp->drawers;
     }
+
+    /*
+     * Machine polarity is set inside the global s390_topology structure.
+     * In the case the polarity is set as horizontal set the entitlement
+     * to POLARITY_VERTICAL_MEDIUM which is the better equivalent when
+     * machine polarity is set to vertical or POLARITY_VERTICAL_HIGH if
+     * the vCPU is dedicated.
+     */
+    if (s390_topology.polarity && !env->entitlement) {
+        if (env->dedicated) {
+            env->entitlement = POLARITY_VERTICAL_HIGH;
+        } else {
+            env->entitlement = POLARITY_VERTICAL_MEDIUM;
+        }
+    }
 }
 
 /**
diff --git a/target/s390x/cpu-sysemu.c b/target/s390x/cpu-sysemu.c
index e27864c5f5..82e3f3891e 100644
--- a/target/s390x/cpu-sysemu.c
+++ b/target/s390x/cpu-sysemu.c
@@ -37,6 +37,7 @@
 #include "sysemu/sysemu.h"
 #include "sysemu/tcg.h"
 #include "hw/core/sysemu-cpu-ops.h"
+#include "hw/s390x/cpu-topology.h"
 
 /* S390CPUClass::load_normal() */
 static void s390_cpu_load_normal(CPUState *s)
@@ -319,3 +320,16 @@ void s390_cpu_topology_reset(void)
         }
     }
 }
+
+void s390_cpu_topology_set_modified(void)
+{
+    int ret;
+
+    if (kvm_enabled()) {
+        ret = kvm_s390_topology_set_mtcr(1);
+        if (ret) {
+            error_report("Failed to set Modified Topology Change Report: %s",
+                         strerror(-ret));
+        }
+    }
+}
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