[Qemu-devel] [PATCH v4] s390: Add CPU reset handler

[Jens Freimann <jfrei@linux.vnet.ibm.com>]

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

Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
---
v3 -> v4:
* don't set psw_mask to z/Architecture in cpu_reset as it
  is done by the ipl device code later on
* make sure patch compiles and runs with s390x-linux-user
  (simple test by running busybox on x86)

v2 -> v3:
* remove FIXME
* separate parent reset from local reset by adding a white line
* use defines for register reset values

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 | 36 ++++++++++++++++++++++++++++++++++--
 target-s390x/kvm.c |  9 ++++++++-
 2 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/target-s390x/cpu.c b/target-s390x/cpu.c
index 249f063..146f079 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
@@ -18,12 +19,19 @@
  * 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"
+#ifndef CONFIG_USER_ONLY
+#include "hw/hw.h"
+#endif
 #include "qemu-common.h"
 #include "qemu/timer.h"
 
+#define CR0_RESET       0xE0UL
+#define CR14_RESET      0xC2000000UL;
 
 /* CPUClass::reset() */
 static void s390_cpu_reset(CPUState *s)
@@ -37,14 +45,33 @@ static void s390_cpu_reset(CPUState *s)
         log_cpu_state(env, 0);
     }
 
+    s390_del_running_cpu(env);
+
     scc->parent_reset(s);
 
     memset(env, 0, offsetof(CPUS390XState, breakpoints));
-    /* FIXME: reset vector? */
+
+    /* architectured initial values for CR 0 and 14 */
+    env->cregs[0] = CR0_RESET;
+    env->cregs[14] = CR14_RESET;
+    /* 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 */
+#if !defined(CONFIG_USER_ONLY)
+    env->halted = 1;
+#endif
     tlb_flush(env, 1);
-    s390_add_running_cpu(env);
 }
 
+#if !defined(CONFIG_USER_ONLY)
+static void s390_cpu_machine_reset_cb(void *opaque)
+{
+    S390CPU *cpu = opaque;
+
+    cpu_reset(CPU(cpu));
+}
+#endif
+
 static void s390_cpu_initfn(Object *obj)
 {
     S390CPU *cpu = S390_CPU(obj);
@@ -56,12 +83,17 @@ static void s390_cpu_initfn(Object *obj)
 
     cpu_exec_init(env);
 #if !defined(CONFIG_USER_ONLY)
+    qemu_register_reset(s390_cpu_machine_reset_cb, cpu);
     qemu_get_timedate(&tm, 0);
     env->tod_offset = TOD_UNIX_EPOCH +
                       (time2tod(mktimegm(&tm)) * 1000000000ULL);
     env->tod_basetime = 0;
     env->tod_timer = qemu_new_timer_ns(vm_clock, s390x_tod_timer, cpu);
     env->cpu_timer = qemu_new_timer_ns(vm_clock, s390x_cpu_timer, cpu);
+    /* 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;
 #endif
     env->cpu_num = cpu_num++;
     env->ext_index = -1;
diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index 6ec5e6d..f116a43 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -85,7 +85,14 @@ int kvm_arch_init_vcpu(CPUState *cpu)
 
 void kvm_arch_reset_vcpu(CPUState *cpu)
 {
-    /* 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(cpu, KVM_S390_INITIAL_RESET, NULL)) {
+        perror("Can't reset vcpu\n");
+    }
 }
 
 int kvm_arch_put_registers(CPUState *cs, int level)
-- 
1.7.12.4