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

3 files changed, 19 insertions, 8 deletions

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 17a71e92a343..95eada2994e1 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -35,7 +35,6 @@
 #include <clocksource/hyperv_timer.h>
 #include <linux/highmem.h>
 
-int hyperv_init_cpuhp;
 u64 hv_current_partition_id = ~0ull;
 EXPORT_SYMBOL_GPL(hv_current_partition_id);
 
@@ -607,8 +606,6 @@ skip_hypercall_pg_init:
 
 	register_syscore_ops(&hv_syscore_ops);
 
-	hyperv_init_cpuhp = cpuhp;
-
 	if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_ACCESS_PARTITION_ID)
 		hv_get_partition_id();
 
@@ -637,7 +634,7 @@ skip_hypercall_pg_init:
 clean_guest_os_id:
 	wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
 	hv_ivm_msr_write(HV_X64_MSR_GUEST_OS_ID, 0);
-	cpuhp_remove_state(cpuhp);
+	cpuhp_remove_state(CPUHP_AP_HYPERV_ONLINE);
 free_ghcb_page:
 	free_percpu(hv_ghcb_pg);
 free_vp_assist_page:
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 390c4d13956d..5f0bc6a6d025 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -40,7 +40,6 @@ static inline unsigned char hv_get_nmi_reason(void)
 }
 
 #if IS_ENABLED(CONFIG_HYPERV)
-extern int hyperv_init_cpuhp;
 extern bool hyperv_paravisor_present;
 
 extern void *hv_hypercall_pg;
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index e0fd57a8ba84..ead967479fa6 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -199,8 +199,8 @@ static void hv_machine_shutdown(void)
 	 * Call hv_cpu_die() on all the CPUs, otherwise later the hypervisor
 	 * corrupts the old VP Assist Pages and can crash the kexec kernel.
 	 */
-	if (kexec_in_progress && hyperv_init_cpuhp > 0)
-		cpuhp_remove_state(hyperv_init_cpuhp);
+	if (kexec_in_progress)
+		cpuhp_remove_state(CPUHP_AP_HYPERV_ONLINE);
 
 	/* The function calls stop_other_cpus(). */
 	native_machine_shutdown();
@@ -424,6 +424,7 @@ static void __init ms_hyperv_init_platform(void)
 	    ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
 		x86_platform.calibrate_tsc = hv_get_tsc_khz;
 		x86_platform.calibrate_cpu = hv_get_tsc_khz;
+		setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
 	}
 
 	if (ms_hyperv.priv_high & HV_ISOLATION) {
@@ -449,9 +450,23 @@ static void __init ms_hyperv_init_platform(void)
 			ms_hyperv.hints &= ~HV_X64_APIC_ACCESS_RECOMMENDED;
 
 			if (!ms_hyperv.paravisor_present) {
-				/* To be supported: more work is required.  */
+				/*
+				 * Mark the Hyper-V TSC page feature as disabled
+				 * in a TDX VM without paravisor so that the
+				 * Invariant TSC, which is a better clocksource
+				 * anyway, is used instead.
+				 */
 				ms_hyperv.features &= ~HV_MSR_REFERENCE_TSC_AVAILABLE;
 
+				/*
+				 * The Invariant TSC is expected to be available
+				 * in a TDX VM without paravisor, but if not,
+				 * print a warning message. The slower Hyper-V MSR-based
+				 * Ref Counter should end up being the clocksource.
+				 */
+				if (!(ms_hyperv.features & HV_ACCESS_TSC_INVARIANT))
+					pr_warn("Hyper-V: Invariant TSC is unavailable\n");
+
 				/* HV_MSR_CRASH_CTL is unsupported. */
 				ms_hyperv.misc_features &= ~HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE;