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authorDmitry Torokhov <dmitry.torokhov@gmail.com>2025-12-13 12:18:20 +0300
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2025-12-13 12:18:20 +0300
commita4a508df2aa34f8650afde54ea804321c618f45f (patch)
treef75f10e7c54f991d7d859f8cbdcc8bcaed5bbd6f /drivers/clocksource/hyperv_timer.c
parentc4b3133c6a2fc283cb3d34c64d40ed2fa254b608 (diff)
parent7d0a66e4bb9081d75c82ec4957c50034cb0ea449 (diff)
downloadlinux-a4a508df2aa34f8650afde54ea804321c618f45f.tar.xz
Merge tag 'v6.18' into next
Sync up with the mainline to bring in the latest APIs.
Diffstat (limited to 'drivers/clocksource/hyperv_timer.c')
-rw-r--r--drivers/clocksource/hyperv_timer.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index 2edc13ca184e..10356d4ec55c 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -549,14 +549,22 @@ static void __init hv_init_tsc_clocksource(void)
union hv_reference_tsc_msr tsc_msr;
/*
+ * When running as a guest partition:
+ *
* If Hyper-V offers TSC_INVARIANT, then the virtualized TSC correctly
* handles frequency and offset changes due to live migration,
* pause/resume, and other VM management operations. So lower the
* Hyper-V Reference TSC rating, causing the generic TSC to be used.
* TSC_INVARIANT is not offered on ARM64, so the Hyper-V Reference
* TSC will be preferred over the virtualized ARM64 arch counter.
+ *
+ * When running as the root partition:
+ *
+ * There is no HV_ACCESS_TSC_INVARIANT feature. Always lower the rating
+ * of the Hyper-V Reference TSC.
*/
- if (ms_hyperv.features & HV_ACCESS_TSC_INVARIANT) {
+ if ((ms_hyperv.features & HV_ACCESS_TSC_INVARIANT) ||
+ hv_root_partition()) {
hyperv_cs_tsc.rating = 250;
hyperv_cs_msr.rating = 245;
}