qemu/ARM64-record-vtimer-tick-when-cpu-is-stopped.patch

From d2fd6d1a5200b9a58863839d21d291cd4f76ac31 Mon Sep 17 00:00:00 2001
From: Ying Fang <fangying1@huawei.com>
Date: Mon, 29 Jul 2019 15:47:27 +0800
Subject: [PATCH] ARM64: record vtimer tick when cpu is stopped

The vtimer kick still increases even if the vcpu is stopped when VM has
save/restore or suspend/resume operation. This will cause guest watchdog
soft-lockup if the VM has lots of memory in use.

Signed-off-by: Hao Hong <honghao5@huawei.com>
Signed-off-by: Haibin Wang <wanghaibin.wang@huawei.com>
Signed-off-by: Ying Fang <fangying1@huawei.com>
---
 cpus.c               | 58 ++++++++++++++++++++++++++++++++++++++++++++
 target/arm/cpu.h     |  2 ++
 target/arm/machine.c |  1 +
 3 files changed, 61 insertions(+)

diff --git a/cpus.c b/cpus.c
index e83f72b4..f6ec48a2 100644
--- a/cpus.c
+++ b/cpus.c
@@ -1063,6 +1063,28 @@ void cpu_synchronize_all_pre_loadvm(void)
     }
 }
 
+#ifdef __aarch64__
+static void get_vcpu_timer_tick(CPUState *cs)
+{
+    CPUARMState *env = &ARM_CPU(cs)->env;
+    int err;
+    struct kvm_one_reg reg;
+    uint64_t timer_tick;
+
+    reg.id = KVM_REG_ARM_TIMER_CNT;
+    reg.addr = (uintptr_t) &timer_tick;
+
+    err = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
+    if (err < 0) {
+        error_report("get vcpu tick failed, ret = %d", err);
+        env->vtimer = 0;
+        return;
+    }
+    env->vtimer = timer_tick;
+    return;
+}
+#endif
+
 static int do_vm_stop(RunState state, bool send_stop)
 {
     int ret = 0;
@@ -1070,6 +1092,11 @@ static int do_vm_stop(RunState state, bool send_stop)
     if (runstate_is_running()) {
         cpu_disable_ticks();
         pause_all_vcpus();
+#ifdef __aarch64__
+        if (first_cpu) {
+            get_vcpu_timer_tick(first_cpu);
+        }
+#endif
         runstate_set(state);
         vm_state_notify(0, state);
         if (send_stop) {
@@ -1909,11 +1936,42 @@ void cpu_resume(CPUState *cpu)
     qemu_cpu_kick(cpu);
 }
 
+#ifdef __aarch64__
+static void set_vcpu_timer_tick(CPUState *cs)
+{
+    CPUARMState *env = &ARM_CPU(cs)->env;
+
+    if (env->vtimer == 0) {
+        return;
+    }
+
+    int err;
+    struct kvm_one_reg reg;
+    uint64_t timer_tick = env->vtimer;
+    env->vtimer = 0;
+
+    reg.id = KVM_REG_ARM_TIMER_CNT;
+    reg.addr = (uintptr_t) &timer_tick;
+
+    err = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
+    if (err < 0) {
+        error_report("Set vcpu tick failed, ret = %d", err);
+        return;
+    }
+    return;
+}
+#endif
+
 void resume_all_vcpus(void)
 {
     CPUState *cpu;
 
     qemu_clock_enable(QEMU_CLOCK_VIRTUAL, true);
+#ifdef __aarch64__
+    if (first_cpu) {
+        set_vcpu_timer_tick(first_cpu);
+    }
+#endif
     CPU_FOREACH(cpu) {
         cpu_resume(cpu);
     }
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index d4d28369..e107e395 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -270,6 +270,8 @@ typedef struct CPUARMState {
     uint64_t elr_el[4]; /* AArch64 exception link regs  */
     uint64_t sp_el[4]; /* AArch64 banked stack pointers */
 
+    uint64_t vtimer; /* Timer tick when vcpu stop */
+
     /* System control coprocessor (cp15) */
     struct {
         uint32_t c0_cpuid;
diff --git a/target/arm/machine.c b/target/arm/machine.c
index b2925496..d64a0057 100644
--- a/target/arm/machine.c
+++ b/target/arm/machine.c
@@ -792,6 +792,7 @@ const VMStateDescription vmstate_arm_cpu = {
         VMSTATE_UINT32(env.exception.syndrome, ARMCPU),
         VMSTATE_UINT32(env.exception.fsr, ARMCPU),
         VMSTATE_UINT64(env.exception.vaddress, ARMCPU),
+        VMSTATE_UINT64(env.vtimer, ARMCPU),
         VMSTATE_TIMER_PTR(gt_timer[GTIMER_PHYS], ARMCPU),
         VMSTATE_TIMER_PTR(gt_timer[GTIMER_VIRT], ARMCPU),
         {
-- 
2.23.0