[Qemu-devel] [PATCH v2 6/9] s390x/cpu: Add functions to (un)register CPU state

[Matthew Rosato <mjrosato@linux.vnet.ibm.com>]

Introduce s390_(un)register_cpustate, which will set the
machine/cpu[n] link with the current CPU state.  Additionally,
maintain an array of state pointers indexed by CPU id for fast lookup
during interrupt handling.

Signed-off-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com>
---
 hw/s390x/s390-virtio.c | 54 +++++++++++++++++++++++++++++++++++++++++---------
 target-s390x/cpu.c     | 14 ++++++++++++-
 target-s390x/cpu.h     |  2 ++
 3 files changed, 60 insertions(+), 10 deletions(-)

diff --git a/hw/s390x/s390-virtio.c b/hw/s390x/s390-virtio.c
index 84cde80..b6effc3 100644
--- a/hw/s390x/s390-virtio.c
+++ b/hw/s390x/s390-virtio.c
@@ -61,17 +61,46 @@
 #define S390_TOD_CLOCK_VALUE_PRESENT    0x01
 
 static VirtIOS390Bus *s390_bus;
-static S390CPU **ipi_states;
+static S390CPU **cpu_states;
 
 S390CPU *s390_cpu_addr2state(uint16_t cpu_addr)
 {
-    if (cpu_addr >= smp_cpus) {
+    if (cpu_addr >= max_cpus) {
         return NULL;
     }
 
-    return ipi_states[cpu_addr];
+    /* Fast lookup via CPU ID */
+    return cpu_states[cpu_addr];
 }
 
+int s390_register_cpustate(uint16_t cpu_addr, S390CPU *state)
+{
+    gchar *name;
+    int r = 0;
+
+    name = g_strdup_printf("cpu[%i]", cpu_addr);
+    if (object_property_get_link(qdev_get_machine(), name, NULL)) {
+        r = -EEXIST;
+        goto out;
+    }
+
+    object_property_set_link(qdev_get_machine(), OBJECT(state), name,\
+                             &error_abort);
+
+out:
+    g_free(name);
+    return r;
+}
+
+void s390_unregister_cpustate(uint16_t cpu_addr)
+{
+    gchar *name;
+
+    name = g_strdup_printf("cpu[%i]", cpu_addr);
+    object_property_set_link(qdev_get_machine(), NULL, name, &error_abort);
+    g_free(name);
+ }
+
 static int s390_virtio_hcall_notify(const uint64_t *args)
 {
     uint64_t mem = args[0];
@@ -171,19 +200,26 @@ void s390_init_ipl_dev(const char *kernel_filename,
 void s390_init_cpus(MachineState *machine)
 {
     int i;
+    gchar *name;
 
     if (machine->cpu_model == NULL) {
         machine->cpu_model = "host";
     }
 
-    ipi_states = g_malloc(sizeof(S390CPU *) * smp_cpus);
+    cpu_states = g_malloc0(sizeof(S390CPU *) * max_cpus);
 
-    for (i = 0; i < smp_cpus; i++) {
-        S390CPU *cpu;
-
-        cpu = cpu_s390x_init(machine->cpu_model);
+    for (i = 0; i < max_cpus; i++) {
+        name = g_strdup_printf("cpu[%i]", i);
+        object_property_add_link(qdev_get_machine(), name, TYPE_S390_CPU,
+                                 (Object **) &cpu_states[i],
+                                 object_property_allow_set_link,
+                                 OBJ_PROP_LINK_UNREF_ON_RELEASE,
+                                 &error_abort);
+        g_free(name);
+    }
 
-        ipi_states[i] = cpu;
+    for (i = 0; i < smp_cpus; i++) {
+        cpu_s390x_init(machine->cpu_model);
     }
 }
 
diff --git a/target-s390x/cpu.c b/target-s390x/cpu.c
index bc821f7..0ef67a1 100644
--- a/target-s390x/cpu.c
+++ b/target-s390x/cpu.c
@@ -31,6 +31,7 @@
 #include "trace.h"
 #ifndef CONFIG_USER_ONLY
 #include "sysemu/arch_init.h"
+#include "sysemu/sysemu.h"
 #endif
 
 #define CR0_RESET       0xE0UL
@@ -201,9 +202,20 @@ static void s390_cpu_realizefn(DeviceState *dev, Error **errp)
     CPUS390XState *env = &cpu->env;
 
 #if !defined(CONFIG_USER_ONLY)
+    if (s390_register_cpustate(next_cpu_id, cpu) < 0) {
+        error_setg(errp, "Cannot have more than %d CPUs", max_cpus);
+        return;
+    }
     qemu_register_reset(s390_cpu_machine_reset_cb, cpu);
-#endif
+    env->cpu_num = next_cpu_id;
+    while (next_cpu_id < max_cpus - 1) {
+        if (!cpu_exists(++next_cpu_id)) {
+            break;
+        }
+    }
+#else
     env->cpu_num = next_cpu_id++;
+#endif
     s390_cpu_gdb_init(cs);
     qemu_init_vcpu(cs);
 #if !defined(CONFIG_USER_ONLY)
diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
index 658cd9d..524a7e4 100644
--- a/target-s390x/cpu.h
+++ b/target-s390x/cpu.h
@@ -531,6 +531,8 @@ static inline int s390_set_clock(uint8_t *tod_high, uint64_t *tod_low)
 }
 
 S390CPU *s390_cpu_addr2state(uint16_t cpu_addr);
+int s390_register_cpustate(uint16_t cpu_addr, S390CPU *state);
+void s390_unregister_cpustate(uint16_t cpu_addr);
 unsigned int s390_cpu_halt(S390CPU *cpu);
 void s390_cpu_unhalt(S390CPU *cpu);
 unsigned int s390_cpu_set_state(uint8_t cpu_state, S390CPU *cpu);
-- 
1.9.1