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Re: [PATCH 2/4] s390x: Cleanup cpu resets


From: Philippe Mathieu-Daudé
Subject: Re: [PATCH 2/4] s390x: Cleanup cpu resets
Date: Fri, 22 Nov 2019 11:35:46 +0100
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1

Hi Janosh,

On 11/22/19 8:52 AM, Janosch Frank wrote:
Let's move the resets into one function and switch by type, so we can
use fallthroughs for shared reset actions.

Signed-off-by: Janosch Frank <address@hidden>
---
  target/s390x/cpu.c | 110 ++++++++++++++++++++-------------------------
  1 file changed, 48 insertions(+), 62 deletions(-)

diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
index 3abe7e80fd..556afecbc1 100644
--- a/target/s390x/cpu.c
+++ b/target/s390x/cpu.c
@@ -82,67 +82,52 @@ static void s390_cpu_load_normal(CPUState *s)
  }
  #endif
-/* S390CPUClass::cpu_reset() */
-static void s390_cpu_reset(CPUState *s)
+typedef enum cpu_reset_type {
+    S390_CPU_RESET_NORMAL,
+    S390_CPU_RESET_INITIAL,
+    S390_CPU_RESET_CLEAR,
+} cpu_reset_type;
+
+static void s390_cpu_reset(CPUState *s, cpu_reset_type type)
  {
      S390CPU *cpu = S390_CPU(s);
      S390CPUClass *scc = S390_CPU_GET_CLASS(cpu);
      CPUS390XState *env = &cpu->env;
- env->pfault_token = -1UL;
-    env->bpbc = false;
      scc->parent_reset(s);
      cpu->env.sigp_order = 0;
      s390_cpu_set_state(S390_CPU_STATE_STOPPED, cpu);
-}
-/* S390CPUClass::initial_reset() */
-static void s390_cpu_initial_reset(CPUState *s)
-{
-    S390CPU *cpu = S390_CPU(s);
-    CPUS390XState *env = &cpu->env;
+    /* Set initial values after clearing */
+    switch (type) {
+    case S390_CPU_RESET_CLEAR:
+        memset(env, 0, offsetof(CPUS390XState, start_initial_reset_fields));
+        /* Fallthrough */
+    case S390_CPU_RESET_INITIAL:
+        memset(&env->start_initial_reset_fields, 0,
+               offsetof(CPUS390XState, end_reset_fields) -
+               offsetof(CPUS390XState, start_initial_reset_fields));
+        /* architectured initial values for CR 0 and 14 */
+        env->cregs[0] = CR0_RESET;
+        env->cregs[14] = CR14_RESET;
- s390_cpu_reset(s);
-    /* initial reset does not clear everything! */
-    memset(&env->start_initial_reset_fields, 0,
-        offsetof(CPUS390XState, end_reset_fields) -
-        offsetof(CPUS390XState, start_initial_reset_fields));
-
-    /* architectured initial values for CR 0 and 14 */
-    env->cregs[0] = CR0_RESET;
-    env->cregs[14] = CR14_RESET;
-
-    /* architectured initial value for Breaking-Event-Address register */
-    env->gbea = 1;
-
-    env->pfault_token = -1UL;
-
-    /* tininess for underflow is detected before rounding */
-    set_float_detect_tininess(float_tininess_before_rounding,
-                              &env->fpu_status);
+        /* architectured initial value for Breaking-Event-Address register */
+        env->gbea = 1;
+        /* tininess for underflow is detected before rounding */
+        set_float_detect_tininess(float_tininess_before_rounding,
+                                  &env->fpu_status);
+        /* Fallthrough */
+    case S390_CPU_RESET_NORMAL:
+        env->pfault_token = -1UL;
+        env->bpbc = false;
+        break;
+    }
/* Reset state inside the kernel that we cannot access yet from QEMU. */
-    if (kvm_enabled()) {
-        kvm_s390_reset_vcpu(cpu);
+    if (kvm_enabled() && (type == S390_CPU_RESET_CLEAR ||
+                          type == S390_CPU_RESET_INITIAL)) {
+            kvm_s390_reset_vcpu(cpu);
      }
-}
-
-/* CPUClass:reset() */
-static void s390_cpu_full_reset(CPUState *s)
-{
-    S390CPU *cpu = S390_CPU(s);
-    S390CPUClass *scc = S390_CPU_GET_CLASS(cpu);
-    CPUS390XState *env = &cpu->env;
-
-    scc->parent_reset(s);
-    cpu->env.sigp_order = 0;
-    s390_cpu_set_state(S390_CPU_STATE_STOPPED, cpu);
-
-    memset(env, 0, offsetof(CPUS390XState, end_reset_fields));
-
-    /* architectured initial values for CR 0 and 14 */
-    env->cregs[0] = CR0_RESET;
-    env->cregs[14] = CR14_RESET;
#if defined(CONFIG_USER_ONLY)
      /* user mode should always be allowed to use the full FPU */
@@ -151,20 +136,21 @@ static void s390_cpu_full_reset(CPUState *s)
          env->cregs[0] |= CR0_VECTOR;
      }
  #endif
+}
- /* architectured initial value for Breaking-Event-Address register */
-    env->gbea = 1;
+static void s390_cpu_reset_normal(CPUState *s)
+{
+    return s390_cpu_reset(s, S390_CPU_RESET_NORMAL);
+}
- env->pfault_token = -1UL;
+static void s390_cpu_reset_initial(CPUState *s)
+{
+    return s390_cpu_reset(s, S390_CPU_RESET_INITIAL);
+}
- /* tininess for underflow is detected before rounding */
-    set_float_detect_tininess(float_tininess_before_rounding,
-                              &env->fpu_status);
-
-    /* Reset state inside the kernel that we cannot access yet from QEMU. */
-    if (kvm_enabled()) {
-        kvm_s390_reset_vcpu(cpu);
-    }
+static void s390_cpu_reset_clear(CPUState *s)
+{
+    return s390_cpu_reset(s, S390_CPU_RESET_CLEAR);
  }
#if !defined(CONFIG_USER_ONLY)
@@ -473,9 +459,9 @@ static void s390_cpu_class_init(ObjectClass *oc, void *data)
  #if !defined(CONFIG_USER_ONLY)
      scc->load_normal = s390_cpu_load_normal;
  #endif
-    scc->cpu_reset = s390_cpu_reset;
-    scc->initial_cpu_reset = s390_cpu_initial_reset;
-    cc->reset = s390_cpu_full_reset;
+    scc->cpu_reset = s390_cpu_reset_normal;
+    scc->initial_cpu_reset = s390_cpu_reset_initial;
+    cc->reset = s390_cpu_reset_clear;
      cc->class_by_name = s390_cpu_class_by_name,
      cc->has_work = s390_cpu_has_work;
  #ifdef CONFIG_TCG


This is a nice cleanup, but the patch is hard to digest.
Maybe you can split it in 3, one patch for each cpu_reset_type.

Regards,

Phil.




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