From: "K. Y. Srinivasan" <kys@microsoft.com>
Date: Thu, 18 May 2017 10:46:02 -0700
Patch-mainline: v4.13-rc1
Subject: Drivers: hv: vmbus: Get the current time from the current clocksource
Git-commit: e546d778d6bb3e1a80697a6556d870c707e6df82
References: fate#323887

The current code uses the MSR based mechanism to get the current tick.
Use the current clock source as that might be more optimal.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Olaf Hering <ohering@suse.de>
---
 arch/x86/include/asm/mshyperv.h | 1 -
 drivers/hv/hv.c                 | 2 +-
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -137,7 +137,6 @@ static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
 	}
 }
 
-#define hv_get_current_tick(tick) rdmsrl(HV_X64_MSR_TIME_REF_COUNT, tick)
 #define hv_init_timer(timer, tick) wrmsrl(timer, tick)
 #define hv_init_timer_config(config, val) wrmsrl(config, val)
 
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -96,7 +96,7 @@ static int hv_ce_set_next_event(unsigned long delta,
 
 	WARN_ON(!clockevent_state_oneshot(evt));
 
-	hv_get_current_tick(current_tick);
+	current_tick = hyperv_cs->read(NULL);
 	current_tick += delta;
 	hv_init_timer(HV_X64_MSR_STIMER0_COUNT, current_tick);
 	return 0;