target-i386: kvm: save/restore steal time MSR

Read and write steal time MSR, so that reporting is functional across
migration.
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

target-i386/cpu.h

@@ -803,6 +803,7 @@ typedef struct CPUX86State {
 #endif
     uint64_t system_time_msr;
     uint64_t wall_clock_msr;
+    uint64_t steal_time_msr;
     uint64_t async_pf_en_msr;
     uint64_t pv_eoi_en_msr;
 

target-i386/kvm.c

@@ -68,6 +68,7 @@ static bool has_msr_tsc_deadline;
 static bool has_msr_async_pf_en;
 static bool has_msr_pv_eoi_en;
 static bool has_msr_misc_enable;
+static bool has_msr_kvm_steal_time;
 static int lm_capable_kernel;
 
 bool kvm_allows_irq0_override(void)
@@ -507,6 +508,8 @@ int kvm_arch_init_vcpu(CPUState *cs)
 
     has_msr_pv_eoi_en = c->eax & (1 << KVM_FEATURE_PV_EOI);
 
+    has_msr_kvm_steal_time = c->eax & (1 << KVM_FEATURE_STEAL_TIME);
+
     cpu_x86_cpuid(env, 0, 0, &limit, &unused, &unused, &unused);
 
     for (i = 0; i <= limit; i++) {
@@ -1107,6 +1110,10 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
             kvm_msr_entry_set(&msrs[n++], MSR_KVM_PV_EOI_EN,
                               env->pv_eoi_en_msr);
         }
+        if (has_msr_kvm_steal_time) {
+            kvm_msr_entry_set(&msrs[n++], MSR_KVM_STEAL_TIME,
+                              env->steal_time_msr);
+        }
         if (hyperv_hypercall_available()) {
             kvm_msr_entry_set(&msrs[n++], HV_X64_MSR_GUEST_OS_ID, 0);
             kvm_msr_entry_set(&msrs[n++], HV_X64_MSR_HYPERCALL, 0);
@@ -1360,6 +1367,9 @@ static int kvm_get_msrs(X86CPU *cpu)
     if (has_msr_pv_eoi_en) {
         msrs[n++].index = MSR_KVM_PV_EOI_EN;
     }
+    if (has_msr_kvm_steal_time) {
+        msrs[n++].index = MSR_KVM_STEAL_TIME;
+    }
 
     if (env->mcg_cap) {
         msrs[n++].index = MSR_MCG_STATUS;
@@ -1445,6 +1455,9 @@ static int kvm_get_msrs(X86CPU *cpu)
         case MSR_KVM_PV_EOI_EN:
             env->pv_eoi_en_msr = msrs[i].data;
             break;
+        case MSR_KVM_STEAL_TIME:
+            env->steal_time_msr = msrs[i].data;
+            break;
         }
     }
 

target-i386/machine.c

@@ -292,6 +292,24 @@ static bool pv_eoi_msr_needed(void *opaque)
     return cpu->env.pv_eoi_en_msr != 0;
 }
 
+static bool steal_time_msr_needed(void *opaque)
+{
+    CPUX86State *cpu = opaque;
+
+    return cpu->steal_time_msr != 0;
+}
+
+static const VMStateDescription vmstate_steal_time_msr = {
+    .name = "cpu/steal_time_msr",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields      = (VMStateField []) {
+        VMSTATE_UINT64(steal_time_msr, CPUX86State),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static const VMStateDescription vmstate_async_pf_msr = {
     .name = "cpu/async_pf_msr",
     .version_id = 1,
@@ -502,6 +520,9 @@ const VMStateDescription vmstate_x86_cpu = {
         } , {
             .vmsd = &vmstate_pv_eoi_msr,
             .needed = pv_eoi_msr_needed,
+        } , {
+            .vmsd = &vmstate_steal_time_msr,
+            .needed = steal_time_msr_needed,
         } , {
             .vmsd = &vmstate_fpop_ip_dp,
             .needed = fpop_ip_dp_needed,