From 1349401ff1aa425e7381ed26feb63e0d6b557fc6 Mon Sep 17 00:00:00 2001 From: Dexuan Cui Date: Tue, 19 Nov 2019 23:12:26 -0800 Subject: clocksource/drivers/hyper-v: Suspend/resume Hyper-V clocksource for hibernation 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 Reviewed-by: Michael Kelley Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/1574233946-48377-1-git-send-email-decui@microsoft.com --- drivers/clocksource/hyperv_timer.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'drivers/clocksource/hyperv_timer.c') diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c index 287d8d58c21a..1aec08e82b7a 100644 --- a/drivers/clocksource/hyperv_timer.c +++ b/drivers/clocksource/hyperv_timer.c @@ -330,12 +330,37 @@ static u64 read_hv_sched_clock_tsc(void) return read_hv_clock_tsc(NULL) - hv_sched_clock_offset; } +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 = virt_to_phys(&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, }; static u64 notrace read_hv_clock_msr(struct clocksource *arg) -- cgit