On Wed, Feb 19, 2025, Yosry Ahmed wrote: > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index 6c56d5235f0f3..729a8ee24037b 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -1478,7 +1478,8 @@ void vmx_vcpu_load_vmcs(struct kvm_vcpu *vcpu, int cpu, > * may switch the active VMCS multiple times). > */ > if (!buddy || WARN_ON_ONCE(buddy->vmcs != prev)) > - indirect_branch_prediction_barrier(); > + if (cpu_feature_enabled(X86_FEATURE_USE_IBPB)) Combine this into a single if-statement, to make it readable and because as-is the outer if would need curly braces. And since this check will stay around in the form of a static_branch, I vote to check it first so that the checks on "buddy" are elided if vcpu_load_ibpb is disabled. That'll mean the WARN_ON_ONCE() won't fire if we have a bug and someone is running with mitigations disabled, but I'm a-ok with that.
