[Qemu-devel] [PATCH 2/3] s390: Add CPU reset handler

[Jens Freimann]

Add a CPU reset handler to have all CPUs in a PoP compliant
state.

Signed-off-by: Jens Freimann <address@hidden>

---
v2 -> v3: 
* explain in comment which code sets cpu 0 to running during IPL

v1 -> v2:
* move setting of control registers and psa to s390_cpu_reset
  and call it from the new s390_machine_cpu_reset_cb()
  This makes it more similar to how it is done on x86
* in s390_cpu_reset() set env->halted state of cpu after
  the memset. This is needed to keep our s390_cpu_running
  counter in sync when s390_cpu_reset is called via the
  qemu_devices_reset path
* set env->halted state in s390_cpu_initfn to 1 to avoid
  decrementing the cpu counter during first reset
---
 target-s390x/cpu.c | 32 ++++++++++++++++++++++++++++++--
 target-s390x/kvm.c |  9 ++++++++-
 2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/target-s390x/cpu.c b/target-s390x/cpu.c
index 619b202..75d4036 100644
--- a/target-s390x/cpu.c
+++ b/target-s390x/cpu.c
@@ -4,6 +4,7 @@
  * Copyright (c) 2009 Ulrich Hecht
  * Copyright (c) 2011 Alexander Graf
  * Copyright (c) 2012 SUSE LINUX Products GmbH
+ * Copyright (c) 2012 IBM Corp.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -18,9 +19,13 @@
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, see
  * <http://www.gnu.org/licenses/lgpl-2.1.html>
+ * Contributions after 2012-12-11 are licensed under the terms of the
+ * GNU GPL, version 2 or (at your option) any later version.
+ *
  */
 
 #include "cpu.h"
+#include "hw/hw.h"
 #include "qemu-common.h"
 #include "qemu-timer.h"
 
@@ -37,12 +42,30 @@ static void s390_cpu_reset(CPUState *s)
         log_cpu_state(env, 0);
     }
 
-    scc->parent_reset(s);
+    s390_del_running_cpu(env);
 
+    scc->parent_reset(s);
     memset(env, 0, offsetof(CPUS390XState, breakpoints));
+
+    /* architectured initial values for CR 0 and 14 */
+    env->cregs[0] = 0xE0UL;
+    env->cregs[14] = 0xC2000000UL;
+    /* set to z/Architecture mode */
+    env->psw.mask = 0x0000000180000000ULL;
+    env->psa = 0;
+    /* set halted to 1 to make sure we can add the cpu in
+     * s390_ipl_cpu code, where env->halted is set back to 0
+     * after incrementing the cpu counter */
+    env->halted = 1;
     /* FIXME: reset vector? */
     tlb_flush(env, 1);
-    s390_add_running_cpu(env);
+}
+
+static void s390_cpu_machine_reset_cb(void *opaque)
+{
+    S390CPU *cpu = opaque;
+
+    cpu_reset(CPU(cpu));
 }
 
 static void s390_cpu_initfn(Object *obj)
@@ -66,7 +89,12 @@ static void s390_cpu_initfn(Object *obj)
     env->cpu_num = cpu_num++;
     env->ext_index = -1;
 
+    /* set env->halted state to 1 to avoid decrementing the running
+     * cpu counter in s390_cpu_reset to a negative number at 
+     * initial ipl */
+    env->halted = 1;
     cpu_reset(CPU(cpu));
+    qemu_register_reset(s390_cpu_machine_reset_cb, cpu);
 }
 
 static void s390_cpu_class_init(ObjectClass *oc, void *data)
diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index 94de764..fda9f1f 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -85,7 +85,14 @@ int kvm_arch_init_vcpu(CPUS390XState *env)
 
 void kvm_arch_reset_vcpu(CPUS390XState *env)
 {
-    /* FIXME: add code to reset vcpu. */
+   /* The initial reset call is needed here to reset in-kernel
+    * vcpu data that we can't access directly from QEMU
+    * (i.e. with older kernels which don't support sync_regs/ONE_REG).
+    * Before this ioctl cpu_synchronize_state() is called in common kvm
+    * code (kvm-all) */
+    if (kvm_vcpu_ioctl(env, KVM_S390_INITIAL_RESET, NULL)) {
+        perror("Can't reset vcpu\n");
+    }
 }
 
 int kvm_arch_put_registers(CPUS390XState *env, int level)
-- 
1.7.12.4