1 files changed, 27 insertions, 17 deletions

diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 78aec160f5e0..7d690d2238f8 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -27,12 +27,14 @@
 #include <linux/sched/clock.h>
 #include <linux/mm.h>
 
+#include <asm/hypervisor.h>
 #include <asm/mem_encrypt.h>
 #include <asm/x86_init.h>
 #include <asm/reboot.h>
 #include <asm/kvmclock.h>
 
 static int kvmclock __initdata = 1;
+static int kvmclock_vsyscall __initdata = 1;
 static int msr_kvm_system_time __ro_after_init = MSR_KVM_SYSTEM_TIME;
 static int msr_kvm_wall_clock __ro_after_init = MSR_KVM_WALL_CLOCK;
 static u64 kvm_sched_clock_offset __ro_after_init;
@@ -44,6 +46,13 @@ static int __init parse_no_kvmclock(char *arg)
 }
 early_param("no-kvmclock", parse_no_kvmclock);
 
+static int __init parse_no_kvmclock_vsyscall(char *arg)
+{
+	kvmclock_vsyscall = 0;
+	return 0;
+}
+early_param("no-kvmclock-vsyscall", parse_no_kvmclock_vsyscall);
+
 /* Aligned to page sizes to match whats mapped via vsyscalls to userspace */
 #define HV_CLOCK_SIZE	(sizeof(struct pvclock_vsyscall_time_info) * NR_CPUS)
 
@@ -228,6 +237,24 @@ static void kvm_shutdown(void)
 	native_machine_shutdown();
 }
 
+static int __init kvm_setup_vsyscall_timeinfo(void)
+{
+#ifdef CONFIG_X86_64
+	u8 flags;
+
+	if (!hv_clock || !kvmclock_vsyscall)
+		return 0;
+
+	flags = pvclock_read_flags(&hv_clock[0].pvti);
+	if (!(flags & PVCLOCK_TSC_STABLE_BIT))
+		return 1;
+
+	kvm_clock.archdata.vclock_mode = VCLOCK_PVCLOCK;
+#endif
+	return 0;
+}
+early_initcall(kvm_setup_vsyscall_timeinfo);
+
 void __init kvmclock_init(void)
 {
 	u8 flags;
@@ -272,20 +299,3 @@ void __init kvmclock_init(void)
 	clocksource_register_hz(&kvm_clock, NSEC_PER_SEC);
 	pv_info.name = "KVM";
 }
-
-int __init kvm_setup_vsyscall_timeinfo(void)
-{
-#ifdef CONFIG_X86_64
-	u8 flags;
-
-	if (!hv_clock)
-		return 0;
-
-	flags = pvclock_read_flags(&hv_clock[0].pvti);
-	if (!(flags & PVCLOCK_TSC_STABLE_BIT))
-		return 1;
-
-	kvm_clock.archdata.vclock_mode = VCLOCK_PVCLOCK;
-#endif
-	return 0;
-}