[Qemu-devel] [PATCH 4/8] [PATCH RFC v2] s390-qemu: cpu hotplug - ipi_states enhancements

["Jason J. Herne" <jjherne@us.ibm.com>]

From: "Jason J. Herne" <jjherne@us.ibm.com>

Modify s390_cpu_addr2state to allow fetching state information for cpu addresses
above the number of online cpus.  Hotplug requires this capability.

Also add s390_cpu_set_state function to allow modification of ipi_state entries
during hotplug.

Finally, add function to find lowest unused ipi_state.

Signed-off-by: Jason J. Herne <jjherne@us.ibm.com>
---
 hw/s390x/s390-virtio.c |   19 ++++++++++++++++---
 target-s390x/cpu.h     |    2 ++
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/hw/s390x/s390-virtio.c b/hw/s390x/s390-virtio.c
index 30d1118..ef4f1ae 100644
--- a/hw/s390x/s390-virtio.c
+++ b/hw/s390x/s390-virtio.c
@@ -54,13 +54,26 @@
 static VirtIOS390Bus *s390_bus;
 static S390CPU **ipi_states;
 
+void s390_cpu_set_state(uint16_t cpu_addr, S390CPU *state)
+{
+    ipi_states[cpu_addr] = state;
+}
+
 S390CPU *s390_cpu_addr2state(uint16_t cpu_addr)
 {
-    if (cpu_addr >= smp_cpus) {
-        return NULL;
+    return ipi_states[cpu_addr];
+}
+
+uint16_t s390_cpu_get_free_state_idx(void)
+{
+    int i;
+    for (i = 0; i < max_cpus; i++)
+        if (ipi_states[i] == NULL) {
+            return i;
     }
 
-    return ipi_states[cpu_addr];
+    assert(0); /* BUG! */
+    return -1;
 }
 
 static int s390_virtio_hcall_notify(const uint64_t *args)
diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
index 6304c4d..029d0c5 100644
--- a/target-s390x/cpu.h
+++ b/target-s390x/cpu.h
@@ -388,6 +388,8 @@ static inline void kvm_s390_interrupt_internal(S390CPU *cpu, int type,
 }
 #endif
 S390CPU *s390_cpu_addr2state(uint16_t cpu_addr);
+void s390_cpu_set_state(uint16_t cpu_addr, S390CPU *state);
+uint16_t s390_cpu_get_free_state_idx(void);
 void s390_add_running_cpu(S390CPU *cpu);
 unsigned s390_del_running_cpu(S390CPU *cpu);
 
-- 
1.7.10.4