[Qemu-devel] [Patch/RFC 05/16] s390x/kvm: Rework SIGP INITIAL CPU RESET handler

[Christian Borntraeger]

From: Thomas Huth <address@hidden>

The s390_cpu_initial_reset() function had two deficiencies: First, it
used an ioctl for the destination CPU, and this ioctl could block
nearly forever, as long as the destination CPU was running in the SIE
loop. Second, it also cleared the general purpose registers - something
it should not do according to the Principles of Operations.
Since we've already got another function for the initial CPU reset in
cpu.c, we can also use that function instead. And by using run_on_cpu()
for executing this code, we make sure that the destination CPU is
correctly kicked out of kernel mode now.

Suggested-by: Christian Borntraeger <address@hidden>
Signed-off-by: Thomas Huth <address@hidden>
Reviewed-by: Cornelia Huck <address@hidden>
Signed-off-by: Christian Borntraeger <address@hidden>
---
 target-s390x/kvm.c | 25 +++++++------------------
 1 file changed, 7 insertions(+), 18 deletions(-)

diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index b93fe84..1f89a89 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -624,25 +624,13 @@ int kvm_s390_cpu_restart(S390CPU *cpu)
     return 0;
 }
 
-static int s390_cpu_initial_reset(S390CPU *cpu)
+static void sigp_initial_cpu_reset(void *arg)
 {
-    CPUState *cs = CPU(cpu);
-    CPUS390XState *env = &cpu->env;
-    int i;
-
-    s390_del_running_cpu(cpu);
-    if (kvm_vcpu_ioctl(cs, KVM_S390_INITIAL_RESET, NULL) < 0) {
-        perror("cannot init reset vcpu");
-    }
+    CPUState *cpu = arg;
+    S390CPUClass *scc = S390_CPU_GET_CLASS(cpu);
 
-    /* Manually zero out all registers */
-    cpu_synchronize_state(cs);
-    for (i = 0; i < 16; i++) {
-        env->regs[i] = 0;
-    }
-
-    DPRINTF("DONE: SIGP initial reset: %p\n", env);
-    return 0;
+    cpu_synchronize_state(cpu);
+    scc->initial_cpu_reset(cpu);
 }
 
 #define SIGP_ORDER_MASK 0x000000ff
@@ -681,7 +669,8 @@ static int handle_sigp(S390CPU *cpu, struct kvm_run *run, 
uint8_t ipa1)
         cc = 1;   /* status stored */
         break;
     case SIGP_INITIAL_CPU_RESET:
-        cc = s390_cpu_initial_reset(target_cpu);
+        run_on_cpu(CPU(target_cpu), sigp_initial_cpu_reset, CPU(target_cpu));
+        cc = 0;
         break;
     default:
         DPRINTF("KVM: unknown SIGP: 0x%x\n", order_code);
-- 
1.8.4.2