This is needed for hibernation, e.g. when we resume the old kernel, we need
to disable the "current" kernel's TSC page and then resume the old kernel's.
Signed-off-by: Dexuan Cui <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
---
drivers/clocksource/hyperv_timer.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index 17b96f9..8f3422c 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -238,12 +238,37 @@ static u64 read_hv_clock_tsc(struct clocksource *arg)
return read_hv_sched_clock_tsc();
}
+static void suspend_hv_clock_tsc(struct clocksource *arg)
+{
+ u64 tsc_msr;
+
+ /* Disable the TSC page */
+ hv_get_reference_tsc(tsc_msr);
+ tsc_msr &= ~BIT_ULL(0);
+ hv_set_reference_tsc(tsc_msr);
+}
+
+
+static void resume_hv_clock_tsc(struct clocksource *arg)
+{
+ phys_addr_t phys_addr = page_to_phys(vmalloc_to_page(tsc_pg));
+ u64 tsc_msr;
+
+ /* Re-enable the TSC page */
+ hv_get_reference_tsc(tsc_msr);
+ tsc_msr &= GENMASK_ULL(11, 0);
+ tsc_msr |= BIT_ULL(0) | (u64)phys_addr;
+ hv_set_reference_tsc(tsc_msr);
+}
+
static struct clocksource hyperv_cs_tsc = {
.name = "hyperv_clocksource_tsc_page",
.rating = 400,
.read = read_hv_clock_tsc,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .suspend= suspend_hv_clock_tsc,
+ .resume = resume_hv_clock_tsc,
};
#endif
--
1.8.3.1