From c0e96acf884a1ce91c9bdd692c6a425b83c90285 Mon Sep 17 00:00:00 2001 From: Dexuan Cui Date: Sat, 8 Apr 2023 14:03:39 -0700 Subject: [PATCH] clocksource: hyper-v: make sure Invariant-TSC is used if it is available If Hyper-V TSC page is unavailable and Invariant-TSC is available, currently hyperv_cs_msr (rather than Invariant-TSC) is used by default. Use Invariant-TSC by default by downgrading hyperv_cs_msr.rating in hv_init_tsc_clocksource(), if Invariant-TSC is available. Signed-off-by: Dexuan Cui Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20230408210339.15085-1-decui@microsoft.com Signed-off-by: Wei Liu --- drivers/clocksource/hyperv_timer.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c index f32948c..bcd9042 100644 --- a/drivers/clocksource/hyperv_timer.c +++ b/drivers/clocksource/hyperv_timer.c @@ -517,9 +517,6 @@ static bool __init hv_init_tsc_clocksource(void) { union hv_reference_tsc_msr tsc_msr; - if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE)) - return false; - /* * If Hyper-V offers TSC_INVARIANT, then the virtualized TSC correctly * handles frequency and offset changes due to live migration, @@ -536,6 +533,9 @@ static bool __init hv_init_tsc_clocksource(void) hyperv_cs_msr.rating = 250; } + if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE)) + return false; + hv_read_reference_counter = read_hv_clock_tsc; /* -- 2.7.4