From: Sean Christopherson <[email protected]> Sent: Wednesday, July 1, 2026 12:32 PM > > Now that all paravirt code that explicitly specifies the TSC frequency > also sets X86_FEATURE_TSC_KNOWN_FREQ, replace all of the one-off code > and simply set X86_FEATURE_TSC_KNOWN_FREQ if the TSC frequency is known. > > Do NOT force set TSC_KNOWN_FREQ if the "known" TSC frequency was provided > by the user. Per commit bd35c77e32e4 ("x86/tsc: Add tsc_early_khz command > line parameter"), one of the goals of the param is to allow the refined > calibration work "to do meaningful error checking". > > No functional change intended. > > Signed-off-by: Sean Christopherson <[email protected]>
For the Hyper-V changes, Reviewed-by: Michael Kelley <[email protected]> > --- > arch/x86/coco/sev/core.c | 1 - > arch/x86/coco/tdx/tdx.c | 1 - > arch/x86/kernel/cpu/acrn.c | 1 - > arch/x86/kernel/cpu/mshyperv.c | 1 - > arch/x86/kernel/cpu/vmware.c | 2 -- > arch/x86/kernel/jailhouse.c | 1 - > arch/x86/kernel/kvmclock.c | 1 - > arch/x86/kernel/tsc.c | 13 ++++++++++--- > arch/x86/xen/time.c | 1 - > 9 files changed, 10 insertions(+), 12 deletions(-) > > diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c > index bc5ae9ef74da..72313b36b6f5 100644 > --- a/arch/x86/coco/sev/core.c > +++ b/arch/x86/coco/sev/core.c > @@ -2027,7 +2027,6 @@ unsigned int __init snp_secure_tsc_init(void) > > secrets = (__force struct snp_secrets_page *)mem; > > - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); > setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); > > rdmsrq(MSR_AMD64_GUEST_TSC_FREQ, tsc_freq_mhz); > diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c > index ae2d35f2ef33..94682aca188b 100644 > --- a/arch/x86/coco/tdx/tdx.c > +++ b/arch/x86/coco/tdx/tdx.c > @@ -1205,7 +1205,6 @@ unsigned int __init tdx_tsc_init(void) > > /* TSC is the only reliable clock in TDX guest */ > setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); > - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); > > return info.crystal_khz * info.numerator / info.denominator; > } > diff --git a/arch/x86/kernel/cpu/acrn.c b/arch/x86/kernel/cpu/acrn.c > index 3818f6ae0629..dc71a6fdd461 100644 > --- a/arch/x86/kernel/cpu/acrn.c > +++ b/arch/x86/kernel/cpu/acrn.c > @@ -40,7 +40,6 @@ static void __init acrn_init_platform(void) > if (acrn_tsc_khz_cpuid) { > x86_init.hyper.get_tsc_khz = acrn_get_tsc_khz; > x86_init.hyper.get_cpu_khz = acrn_get_tsc_khz; > - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); > } > } > > diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c > index f9bc1c2d8c93..e03c69a4db33 100644 > --- a/arch/x86/kernel/cpu/mshyperv.c > +++ b/arch/x86/kernel/cpu/mshyperv.c > @@ -575,7 +575,6 @@ static void __init ms_hyperv_init_platform(void) > ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { > x86_init.hyper.get_tsc_khz = hv_get_tsc_khz; > x86_init.hyper.get_cpu_khz = hv_get_tsc_khz; > - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); > } > > if (ms_hyperv.priv_high & HV_ISOLATION) { > diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c > index 3cb473cae462..0a3bd90576d4 100644 > --- a/arch/x86/kernel/cpu/vmware.c > +++ b/arch/x86/kernel/cpu/vmware.c > @@ -390,8 +390,6 @@ static void __init vmware_set_capabilities(void) > { > setup_force_cpu_cap(X86_FEATURE_CONSTANT_TSC); > setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); > - if (vmware_tsc_khz) > - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); > if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMCALL) > setup_force_cpu_cap(X86_FEATURE_VMCALL); > else if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMMCALL) > diff --git a/arch/x86/kernel/jailhouse.c b/arch/x86/kernel/jailhouse.c > index e24c05ab4fae..ff173052cdce 100644 > --- a/arch/x86/kernel/jailhouse.c > +++ b/arch/x86/kernel/jailhouse.c > @@ -255,7 +255,6 @@ static void __init jailhouse_init_platform(void) > pr_debug("Jailhouse: PM-Timer IO Port: %#x\n", pmtmr_ioport); > > precalibrated_tsc_khz = setup_data.v1.tsc_khz; > - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); > > pci_probe = 0; > > diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c > index 4f8299303a19..35a879d33e9e 100644 > --- a/arch/x86/kernel/kvmclock.c > +++ b/arch/x86/kernel/kvmclock.c > @@ -138,7 +138,6 @@ static inline void kvm_sched_clock_init(bool stable) > */ > static unsigned int __init kvm_get_tsc_khz(void) > { > - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); > return pvclock_tsc_khz(this_cpu_pvti()); > } > > diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c > index 1dca9464b41c..676910292af7 100644 > --- a/arch/x86/kernel/tsc.c > +++ b/arch/x86/kernel/tsc.c > @@ -1541,11 +1541,18 @@ void __init tsc_early_init(void) > if (!known_tsc_khz && x86_init.hyper.get_tsc_khz) > known_tsc_khz = x86_init.hyper.get_tsc_khz(); > > + /* > + * Mark the TSC frequency as known if it was obtained from a hypervisor > + * or trusted firmware. > + */ > + if (known_tsc_khz) > + setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); > + > /* > * Ignore the user-provided TSC frequency if the exact frequency was > - * obtained from trusted firmware or the hypervisor, as the user- > - * provided frequency is intended as a "starting point", not a known, > - * guaranteed frequency. > + * obtained from trusted firmware or the hypervisor, and don't mark the > + * frequency as known, as the user-provided frequency is intended as a > + * "starting point", not a known, guaranteed frequency > */ > if (!known_tsc_khz) > known_tsc_khz = tsc_early_khz; > diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c > index 1adb44fdddb2..487ad838c441 100644 > --- a/arch/x86/xen/time.c > +++ b/arch/x86/xen/time.c > @@ -43,7 +43,6 @@ static unsigned int __init xen_tsc_khz(void) > struct pvclock_vcpu_time_info *info = > &HYPERVISOR_shared_info->vcpu_info[0].time; > > - setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); > return pvclock_tsc_khz(info); > } > > -- > 2.55.0.rc0.799.gd6f94ed593-goog >
