x86/vmware: Enable steal time accounting

Set paravirt_steal_rq_enabled if steal clock present.
paravirt_steal_rq_enabled is used in sched/core.c to adjust task
progress by offsetting stolen time. Use 'no-steal-acc' off switch (share
same name with KVM) to disable steal time accounting.

Signed-off-by: Alexey Makhalov <amakhalov@vmware.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200323195707.31242-5-amakhalov@vmware.com

Documentation/admin-guide/kernel-parameters.txt

@@ -3174,7 +3174,7 @@
 			[X86,PV_OPS] Disable paravirtualized VMware scheduler
 			clock and use the default one.
 
-	no-steal-acc	[X86,KVM,ARM64] Disable paravirtualized steal time
+	no-steal-acc	[X86,PV_OPS,ARM64] Disable paravirtualized steal time
 			accounting. steal time is computed, but won't
 			influence scheduler behaviour
 

arch/x86/kernel/cpu/vmware.c

@@ -125,6 +125,7 @@ static struct cyc2ns_data vmware_cyc2ns __ro_after_init;
 static int vmw_sched_clock __initdata = 1;
 static DEFINE_PER_CPU_DECRYPTED(struct vmware_steal_time, vmw_steal_time) __aligned(64);
 static bool has_steal_clock;
+static bool steal_acc __initdata = true; /* steal time accounting */
 
 static __init int setup_vmw_sched_clock(char *s)
 {
@@ -133,6 +134,13 @@ static __init int setup_vmw_sched_clock(char *s)
 }
 early_param("no-vmw-sched-clock", setup_vmw_sched_clock);
 
+static __init int parse_no_stealacc(char *arg)
+{
+	steal_acc = false;
+	return 0;
+}
+early_param("no-steal-acc", parse_no_stealacc);
+
 static unsigned long long notrace vmware_sched_clock(void)
 {
 	unsigned long long ns;
@@ -306,8 +314,11 @@ static int vmware_cpu_down_prepare(unsigned int cpu)
 
 static __init int activate_jump_labels(void)
 {
-	if (has_steal_clock)
+	if (has_steal_clock) {
 		static_key_slow_inc(&paravirt_steal_enabled);
+		if (steal_acc)
+			static_key_slow_inc(&paravirt_steal_rq_enabled);
+	}
 
 	return 0;
 }