4 files changed, 84 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index fd248a318211..a7225746ed96 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1737,6 +1737,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
         no-kvmapf       [X86,KVM] Disable paravirtualized asynchronous page
                         fault handling.
 
+        no-steal-acc    [X86,KVM] Disable paravirtualized steal time accounting.
+                        steal time is computed, but won't influence scheduler
+                        behaviour
+
         nolapic         [X86-32,APIC] Do not enable or use the local APIC.
 
         nolapic_timer   [X86-32,APIC] Do not use the local APIC timer.
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index c484ba8e05ea..734c3767cfac 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -192,6 +192,7 @@ void __init kvm_guest_init(void);
 void kvm_async_pf_task_wait(u32 token);
 void kvm_async_pf_task_wake(u32 token);
 u32 kvm_read_and_reset_pf_reason(void);
+extern void kvm_disable_steal_time(void);
 #else
 #define kvm_guest_init() do { } while (0)
 #define kvm_async_pf_task_wait(T) do {} while(0)
@@ -200,6 +201,11 @@ static inline u32 kvm_read_and_reset_pf_reason(void)
 {
         return 0;
 }
+
+static inline void kvm_disable_steal_time(void)
+{
+        return;
+}
 #endif
 
 #endif /* __KERNEL__ */
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 33c07b0b122e..a9c2116001d6 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -51,6 +51,15 @@ static int parse_no_kvmapf(char *arg)
 
 early_param("no-kvmapf", parse_no_kvmapf);
 
+static int steal_acc = 1;
+static int parse_no_stealacc(char *arg)
+{
+        steal_acc = 0;
+        return 0;
+}
+
+early_param("no-steal-acc", parse_no_stealacc);
+
 struct kvm_para_state {
         u8 mmu_queue[MMU_QUEUE_SIZE];
         int mmu_queue_len;
@@ -58,6 +67,8 @@ struct kvm_para_state {
 
 static DEFINE_PER_CPU(struct kvm_para_state, para_state);
 static DEFINE_PER_CPU(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);
+static DEFINE_PER_CPU(struct kvm_steal_time, steal_time) __aligned(64);
+static int has_steal_clock = 0;
 
 static struct kvm_para_state *kvm_para_state(void)
 {
@@ -441,6 +452,21 @@ static void __init paravirt_ops_setup(void)
 #endif
 }
 
+static void kvm_register_steal_time(void)
+{
+        int cpu = smp_processor_id();
+        struct kvm_steal_time *st = &per_cpu(steal_time, cpu);
+
+        if (!has_steal_clock)
+                return;
+
+        memset(st, 0, sizeof(*st));
+
+        wrmsrl(MSR_KVM_STEAL_TIME, (__pa(st) | KVM_MSR_ENABLED));
+        printk(KERN_INFO "kvm-stealtime: cpu %d, msr %lx\n",
+                cpu, __pa(st));
+}
+
 void __cpuinit kvm_guest_cpu_init(void)
 {
         if (!kvm_para_available())
@@ -457,6 +483,9 @@ void __cpuinit kvm_guest_cpu_init(void)
                 printk(KERN_INFO"KVM setup async PF for cpu %d\n",
                        smp_processor_id());
         }
+
+        if (has_steal_clock)
+                kvm_register_steal_time();
 }
 
 static void kvm_pv_disable_apf(void *unused)
@@ -483,6 +512,31 @@ static struct notifier_block kvm_pv_reboot_nb = {
         .notifier_call = kvm_pv_reboot_notify,
 };
 
+static u64 kvm_steal_clock(int cpu)
+{
+        u64 steal;
+        struct kvm_steal_time *src;
+        int version;
+
+        src = &per_cpu(steal_time, cpu);
+        do {
+                version = src->version;
+                rmb();
+                steal = src->steal;
+                rmb();
+        } while ((version & 1) || (version != src->version));
+
+        return steal;
+}
+
+void kvm_disable_steal_time(void)
+{
+        if (!has_steal_clock)
+                return;
+
+        wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
+}
+
 #ifdef CONFIG_SMP
 static void __init kvm_smp_prepare_boot_cpu(void)
 {
@@ -500,6 +554,7 @@ static void __cpuinit kvm_guest_cpu_online(void *dummy)
 
 static void kvm_guest_cpu_offline(void *dummy)
 {
+        kvm_disable_steal_time();
         kvm_pv_disable_apf(NULL);
         apf_task_wake_all();
 }
@@ -548,6 +603,11 @@ void __init kvm_guest_init(void)
         if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF))
                 x86_init.irqs.trap_init = kvm_apf_trap_init;
 
+        if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
+                has_steal_clock = 1;
+                pv_time_ops.steal_clock = kvm_steal_clock;
+        }
+
 #ifdef CONFIG_SMP
         smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
         register_cpu_notifier(&kvm_cpu_notifier);
@@ -555,3 +615,15 @@ void __init kvm_guest_init(void)
         kvm_guest_cpu_init();
 #endif
 }
+
+static __init int activate_jump_labels(void)
+{
+        if (has_steal_clock) {
+                jump_label_inc(&paravirt_steal_enabled);
+                if (steal_acc)
+                        jump_label_inc(&paravirt_steal_rq_enabled);
+        }
+
+        return 0;
+}
+arch_initcall(activate_jump_labels);
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 6389a6bca11b..c1a0188e29ae 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -160,6 +160,7 @@ static void __cpuinit kvm_setup_secondary_clock(void)
 static void kvm_crash_shutdown(struct pt_regs *regs)
 {
         native_write_msr(msr_kvm_system_time, 0, 0);
+        kvm_disable_steal_time();
         native_machine_crash_shutdown(regs);
 }
 #endif
@@ -167,6 +168,7 @@ static void kvm_crash_shutdown(struct pt_regs *regs)
 static void kvm_shutdown(void)
 {
         native_write_msr(msr_kvm_system_time, 0, 0);
+        kvm_disable_steal_time();
         native_machine_shutdown();
 }