On 02/11/2011 08:19 PM, Glauber Costa wrote:
Register steal time within KVM. Everytime we sample the steal time
information, we update a local variable that tells what was the
last time read. We then account the difference.
+static int kvm_register_steal_time(void)
+{
+ int cpu = smp_processor_id();
+ int low, high, ret;
+ struct kvm_steal_time *st =&per_cpu(steal_time, cpu);
+
+ if (!hypervisor_steal_time)
+ return 0;
You're using hypervisor_steal_time to communicate the existence of the
feature. Yuck.
+
+ memset(st, 0, sizeof(*st));
+
+ low = (int)__pa(st) | 1;
Named constant.
+ high = ((u64)__pa(st)>> 32);
+ ret = wrmsr_safe(MSR_KVM_STEAL_TIME, low, high);
No need for wrmsr_safe() since you're checking the cpuid bit. The other
APIs are nicer (no need to break into two words).
+ printk(KERN_INFO "kvm-stealtime: cpu %d, msr %x:%x\n",
+ cpu, high, low);
+ return ret;
+}
+
#ifdef CONFIG_SMP
static void __init kvm_smp_prepare_boot_cpu(void)
{
#ifdef CONFIG_KVM_CLOCK
WARN_ON(kvm_register_clock("primary cpu clock"));
#endif
+ WARN_ON(kvm_register_steal_time());
kvm_guest_cpu_init();
native_smp_prepare_boot_cpu();
}
static void __cpuinit kvm_guest_cpu_online(void *dummy)
{
+ WARN_ON(kvm_register_steal_time());
kvm_guest_cpu_init();
}
static void kvm_guest_cpu_offline(void *dummy)
{
kvm_pv_disable_apf(NULL);
+ wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
This will trap if running on a hypervisor without this MSR.
apf_task_wake_all();
}
@@ -534,6 +557,23 @@ static void __init kvm_apf_trap_init(void)
set_intr_gate(14,&async_page_fault);
}
+static u64 kvm_account_steal_time(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 ((src->version& 1) || (version != src->version));
Check version & 1 instead of src->version & 1, slightly cheaper.
+
+ return steal;
+}
+
index f98d3ea..dcb6a67 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -164,6 +164,7 @@ 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);
+ wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
native_machine_crash_shutdown(regs);
}
Make conditional. Needed for the previous wrmsr as well.
#endif
@@ -171,6 +172,7 @@ static void kvm_crash_shutdown(struct pt_regs *regs)
static void kvm_shutdown(void)
{
native_write_msr(msr_kvm_system_time, 0, 0);
+ wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
native_machine_shutdown();
}
Ditto. Is it me, or is the code duplicated?
--
error compiling committee.c: too many arguments to function
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