s390: Fix cpu shutdown for KVM

On s390 a shutdown is the state of all CPUs being either stopped
or disabled (for interrupts) waiting. We have to track the overall
number of running CPUs to call the shutdown sequence accordingly.
This patch implements the counting and shutdown handling for the
kvm path in qemu.
Lets also wrap changes to env->halted and env->exception_index.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

diff --git a/hw/s390-virtio.c b/hw/s390-virtio.c
index ee850f05594a5374d1fa42da161435f8e420b50c..37945d5d8388c3e97f5d3c065728f386ae3206c1 100644 (file)
--- a/hw/s390-virtio.c
+++ b/hw/s390-virtio.c
@@ -121,6 +121,34 @@ int s390_virtio_hypercall(CPUState *env, uint64_t mem, uint64_t hypercall)
     return r;
 }
 
+/*
+ * The number of running CPUs. On s390 a shutdown is the state of all CPUs
+ * being either stopped or disabled (for interrupts) waiting. We have to
+ * track this number to call the shutdown sequence accordingly. This
+ * number is modified either on startup or while holding the big qemu lock.
+ */
+static unsigned s390_running_cpus;
+
+void s390_add_running_cpu(CPUState *env)
+{
+    if (env->halted) {
+        s390_running_cpus++;
+        env->halted = 0;
+        env->exception_index = -1;
+    }
+}
+
+unsigned s390_del_running_cpu(CPUState *env)
+{
+    if (env->halted == 0) {
+        assert(s390_running_cpus >= 1);
+        s390_running_cpus--;
+        env->halted = 1;
+        env->exception_index = EXCP_HLT;
+    }
+    return s390_running_cpus;
+}
+
 /* PC hardware initialisation */
 static void s390_init(ram_addr_t my_ram_size,
                       const char *boot_device,
@@ -179,8 +207,8 @@ static void s390_init(ram_addr_t my_ram_size,
         tmp_env->storage_keys = storage_keys;
     }
 
-    env->halted = 0;
-    env->exception_index = 0;
+    /* One CPU has to run */
+    s390_add_running_cpu(env);
 
     if (kernel_filename) {
         kernel_size = load_image(kernel_filename, qemu_get_ram_ptr(0));

diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
index 95abe595b36b4998d81b9060f0d8ffbb08c33dc0..a66aa0166b63d94270c2426050e0a7ce924d26bd 100644 (file)
--- a/target-s390x/cpu.h
+++ b/target-s390x/cpu.h
@@ -309,6 +309,8 @@ static inline void kvm_s390_interrupt_internal(CPUState *env, int type,
 }
 #endif
 CPUState *s390_cpu_addr2state(uint16_t cpu_addr);
+void s390_add_running_cpu(CPUState *env);
+unsigned s390_del_running_cpu(CPUState *env);
 
 /* from s390-virtio-bus */
 extern const target_phys_addr_t virtio_size;

diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index 4beb794ccae0d2911a9e1cf4e811c614bbd5f0b3..40b0ab19225a87a7782f43fc05fe62fbbfe38636 100644 (file)
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -185,8 +185,7 @@ void kvm_s390_interrupt_internal(CPUState *env, int type, uint32_t parm,
         return;
     }
 
-    env->halted = 0;
-    env->exception_index = -1;
+    s390_add_running_cpu(env);
     qemu_cpu_kick(env);
 
     kvmint.type = type;
@@ -299,8 +298,7 @@ static int handle_diag(CPUState *env, struct kvm_run *run, int ipb_code)
 static int s390_cpu_restart(CPUState *env)
 {
     kvm_s390_interrupt(env, KVM_S390_RESTART, 0);
-    env->halted = 0;
-    env->exception_index = -1;
+    s390_add_running_cpu(env);
     qemu_cpu_kick(env);
     dprintf("DONE: SIGP cpu restart: %p\n", env);
     return 0;
@@ -425,17 +423,16 @@ static int handle_intercept(CPUState *env)
             r = handle_instruction(env, run);
             break;
         case ICPT_WAITPSW:
-            /* XXX What to do on system shutdown? */
-            env->halted = 1;
-            env->exception_index = EXCP_HLT;
+        case ICPT_CPU_STOP:
+            if (s390_del_running_cpu(env) == 0) {
+                qemu_system_shutdown_request();
+            }
+            r = EXCP_HALTED;
             break;
         case ICPT_SOFT_INTERCEPT:
             fprintf(stderr, "KVM unimplemented icpt SOFT\n");
             exit(1);
             break;
-        case ICPT_CPU_STOP:
-            qemu_system_shutdown_request();
-            break;
         case ICPT_IO:
             fprintf(stderr, "KVM unimplemented icpt IO\n");
             exit(1);
@@ -468,8 +465,6 @@ int kvm_arch_handle_exit(CPUState *env, struct kvm_run *run)
 
     if (ret == 0) {
         ret = EXCP_INTERRUPT;
-    } else if (ret > 0) {
-        ret = 0;
     }
     return ret;
 }