Commit 7d4163c8 authored by Wei Liu's avatar Wei Liu
Browse files

clocksource/hyperv: use MSR-based access if running as root 



When Linux runs as the root partition, the setup required for TSC page
is different. Luckily Linux also has access to the MSR based
clocksource. We can just disable the TSC page clocksource if Linux is
the root partition.

Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
Acked-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: default avatarPavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-5-wei.liu@kernel.org
parent 7e279d78

drivers/clocksource/hyperv_timer.c

+3 −0
Original line number Diff line number Diff line
@@ -426,6 +426,9 @@ static bool __init hv_init_tsc_clocksource(void) 
	if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE))

		return false;



	if (hv_root_partition)

		return false;



	hv_read_reference_counter = read_hv_clock_tsc;

	phys_addr = virt_to_phys(hv_get_tsc_page());