s390x/tcg: properly implement the TOD

Right now, each CPU has its own TOD. Especially, the TOD will differ
based on creation time of a CPU - e.g. when hotplugging a CPU the times
will differ quite a lot, resulting in stall warnings in the guest.

Let's use a single TOD by implementing our new TOD device. Prepare it
for TOD-clock epoch extension.

Most importantly, whenever we set the TOD, we have to update the CKC
timer.

Introduce "tcg_s390x.h" just like "kvm_s390x.h" for tcg specific
function declarations that should not go into cpu.h.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180627134410.4901-6-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

5 files changed, 37 insertions, 30 deletions

diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
index a41b3f3..40d6980 100644
--- a/target/s390x/cpu.c
+++ b/target/s390x/cpu.c
@@ -30,7 +30,6 @@
 #include "kvm_s390x.h"
 #include "sysemu/kvm.h"
 #include "qemu-common.h"
-#include "qemu/cutils.h"
 #include "qemu/timer.h"
 #include "qemu/error-report.h"
 #include "trace.h"
@@ -275,9 +274,6 @@ static void s390_cpu_initfn(Object *obj)
     CPUState *cs = CPU(obj);
     S390CPU *cpu = S390_CPU(obj);
     CPUS390XState *env = &cpu->env;
-#if !defined(CONFIG_USER_ONLY)
-    struct tm tm;
-#endif
 
     cs->env_ptr = env;
     cs->halted = 1;
@@ -286,9 +282,6 @@ static void s390_cpu_initfn(Object *obj)
                         s390_cpu_get_crash_info_qom, NULL, NULL, NULL, NULL);
     s390_cpu_model_register_props(obj);
 #if !defined(CONFIG_USER_ONLY)
-    qemu_get_timedate(&tm, 0);
-    env->tod_offset = TOD_UNIX_EPOCH +
-                      (time2tod(mktimegm(&tm)) * 1000000000ULL);
     env->tod_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, s390x_tod_timer, cpu);
     env->cpu_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, s390x_cpu_timer, cpu);
     s390_cpu_set_state(S390_CPU_STATE_STOPPED, cpu);
diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index 4abfe88..2c3dd2d 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -130,7 +130,6 @@ struct CPUS390XState {
     uint64_t cpuid;
 #endif
 
-    uint64_t tod_offset;
     QEMUTimer *tod_timer;
 
     QEMUTimer *cpu_timer;
diff --git a/target/s390x/internal.h b/target/s390x/internal.h
index 6cf6334..f2a771e 100644
--- a/target/s390x/internal.h
+++ b/target/s390x/internal.h
@@ -237,22 +237,6 @@ enum cc_op {
     CC_OP_MAX
 };
 
-/* The value of the TOD clock for 1.1.1970. */
-#define TOD_UNIX_EPOCH 0x7d91048bca000000ULL
-
-/* Converts ns to s390's clock format */
-static inline uint64_t time2tod(uint64_t ns)
-{
-    return (ns << 9) / 125 + (((ns & 0xff10000000000000ull) / 125) << 9);
-
-}
-
-/* Converts s390's clock format to ns */
-static inline uint64_t tod2time(uint64_t t)
-{
-    return ((t >> 9) * 125) + (((t & 0x1ff) * 125) >> 9);
-}
-
 static inline hwaddr decode_basedisp_s(CPUS390XState *env, uint32_t ipb,
                                        uint8_t *ar)
 {
diff --git a/target/s390x/misc_helper.c b/target/s390x/misc_helper.c
index dd52739..229f14d 100644
--- a/target/s390x/misc_helper.c
+++ b/target/s390x/misc_helper.c
@@ -28,6 +28,8 @@
 #include "qemu/timer.h"
 #include "exec/exec-all.h"
 #include "exec/cpu_ldst.h"
+#include "qapi/error.h"
+#include "tcg_s390x.h"
 
 #if !defined(CONFIG_USER_ONLY)
 #include "sysemu/cpus.h"
@@ -39,6 +41,7 @@
 #include "hw/s390x/ioinst.h"
 #include "hw/s390x/s390-pci-inst.h"
 #include "hw/boards.h"
+#include "hw/s390x/tod.h"
 #endif
 
 /* #define DEBUG_HELPER */
@@ -138,17 +141,19 @@ void HELPER(spx)(CPUS390XState *env, uint64_t a1)
 /* Store Clock */
 uint64_t HELPER(stck)(CPUS390XState *env)
 {
-    uint64_t time;
+    S390TODState *td = s390_get_todstate();
+    S390TODClass *tdc = S390_TOD_GET_CLASS(td);
+    S390TOD tod;
 
-    time = env->tod_offset +
-        time2tod(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
-
-    return time;
+    tdc->get(td, &tod, &error_abort);
+    return tod.low;
 }
 
 /* Set Clock Comparator */
 void HELPER(sckc)(CPUS390XState *env, uint64_t time)
 {
+    S390TODState *td = s390_get_todstate();
+
     if (time == -1ULL) {
         return;
     }
@@ -156,7 +161,7 @@ void HELPER(sckc)(CPUS390XState *env, uint64_t time)
     env->ckc = time;
 
     /* difference between origins */
-    time -= env->tod_offset;
+    time -= td->base.low;
 
     /* nanoseconds */
     time = tod2time(time);
@@ -164,6 +169,14 @@ void HELPER(sckc)(CPUS390XState *env, uint64_t time)
     timer_mod(env->tod_timer, time);
 }
 
+void tcg_s390_tod_updated(CPUState *cs, run_on_cpu_data opaque)
+{
+    S390CPU *cpu = S390_CPU(cs);
+    CPUS390XState *env = &cpu->env;
+
+    helper_sckc(env, env->ckc);
+}
+
 /* Set Tod Programmable Field */
 void HELPER(sckpf)(CPUS390XState *env, uint64_t r0)
 {
diff --git a/target/s390x/tcg_s390x.h b/target/s390x/tcg_s390x.h
new file mode 100644
index 0000000..4e308aa
--- /dev/null
+++ b/target/s390x/tcg_s390x.h
@@ -0,0 +1,18 @@
+/*
+ * QEMU TCG support -- s390x specific functions.
+ *
+ * Copyright 2018 Red Hat, Inc.
+ *
+ * Authors:
+ *   David Hildenbrand <david@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef TCG_S390X_H
+#define TCG_S390X_H
+
+void tcg_s390_tod_updated(CPUState *cs, run_on_cpu_data opaque);
+
+#endif /* TCG_S390X_H */