Merge tag 'hyperv-fixes-signed-20240908' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv fixes from Wei Liu:

 - Add a documentation overview of Confidential Computing VM support
   (Michael Kelley)

 - Use lapic timer in a TDX VM without paravisor (Dexuan Cui)

 - Set X86_FEATURE_TSC_KNOWN_FREQ when Hyper-V provides frequency
   (Michael Kelley)

 - Fix a kexec crash due to VP assist page corruption (Anirudh
   Rayabharam)

 - Python3 compatibility fix for lsvmbus (Anthony Nandaa)

 - Misc fixes (Rachel Menge, Roman Kisel, zhang jiao, Hongbo Li)

* tag 'hyperv-fixes-signed-20240908' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  hv: vmbus: Constify struct kobj_type and struct attribute_group
  tools: hv: rm .*.cmd when make clean
  x86/hyperv: fix kexec crash due to VP assist page corruption
  Drivers: hv: vmbus: Fix the misplaced function description
  tools: hv: lsvmbus: change shebang to use python3
  x86/hyperv: Set X86_FEATURE_TSC_KNOWN_FREQ when Hyper-V provides frequency
  Documentation: hyperv: Add overview of Confidential Computing VM support
  clocksource: hyper-v: Use lapic timer in a TDX VM without paravisor
  Drivers: hv: Remove deprecated hv_fcopy declarations

1 files changed, 15 insertions, 1 deletions

diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index b2a080647e41..99177835cade 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -137,7 +137,21 @@ static int hv_stimer_init(unsigned int cpu)
 	ce->name = "Hyper-V clockevent";
 	ce->features = CLOCK_EVT_FEAT_ONESHOT;
 	ce->cpumask = cpumask_of(cpu);
-	ce->rating = 1000;
+
+	/*
+	 * Lower the rating of the Hyper-V timer in a TDX VM without paravisor,
+	 * so the local APIC timer (lapic_clockevent) is the default timer in
+	 * such a VM. The Hyper-V timer is not preferred in such a VM because
+	 * it depends on the slow VM Reference Counter MSR (the Hyper-V TSC
+	 * page is not enbled in such a VM because the VM uses Invariant TSC
+	 * as a better clocksource and it's challenging to mark the Hyper-V
+	 * TSC page shared in very early boot).
+	 */
+	if (!ms_hyperv.paravisor_present && hv_isolation_type_tdx())
+		ce->rating = 90;
+	else
+		ce->rating = 1000;
+
 	ce->set_state_shutdown = hv_ce_shutdown;
 	ce->set_state_oneshot = hv_ce_set_oneshot;
 	ce->set_next_event = hv_ce_set_next_event;