#include <asm/msr.h>
#include <asm/apic.h>
#include <linux/percpu.h>
+#include <asm/reboot.h>
#define KVM_SCALE 22
return native_write_msr_safe(MSR_KVM_SYSTEM_TIME, low, high);
}
+#ifdef CONFIG_X86_LOCAL_APIC
static void kvm_setup_secondary_clock(void)
{
/*
/* ok, done with our trickery, call native */
setup_secondary_APIC_clock();
}
+#endif
+
+/*
+ * After the clock is registered, the host will keep writing to the
+ * registered memory location. If the guest happens to shutdown, this memory
+ * won't be valid. In cases like kexec, in which you install a new kernel, this
+ * means a random memory location will be kept being written. So before any
+ * kind of shutdown from our side, we unregister the clock by writting anything
+ * that does not have the 'enable' bit set in the msr
+ */
+#ifdef CONFIG_KEXEC
+static void kvm_crash_shutdown(struct pt_regs *regs)
+{
+ native_write_msr_safe(MSR_KVM_SYSTEM_TIME, 0, 0);
+ native_machine_crash_shutdown(regs);
+}
+#endif
+
+static void kvm_shutdown(void)
+{
+ native_write_msr_safe(MSR_KVM_SYSTEM_TIME, 0, 0);
+ native_machine_shutdown();
+}
void __init kvmclock_init(void)
{
pv_time_ops.get_wallclock = kvm_get_wallclock;
pv_time_ops.set_wallclock = kvm_set_wallclock;
pv_time_ops.sched_clock = kvm_clock_read;
+#ifdef CONFIG_X86_LOCAL_APIC
pv_apic_ops.setup_secondary_clock = kvm_setup_secondary_clock;
+#endif
+ machine_ops.shutdown = kvm_shutdown;
+#ifdef CONFIG_KEXEC
+ machine_ops.crash_shutdown = kvm_crash_shutdown;
+#endif
clocksource_register(&kvm_clock);
}
}