KVM: x86: Use wbinvd_on_cpu() instead of an open-coded equivalent

Use wbinvd_on_cpu() to target a single CPU instead of open-coding an
equivalent, and drop KVM's wbinvd_ipi() now that all users have switched
to x86 library versions.

No functional change intended.

Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20250522233733.3176144-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: sean-jc

arch/x86/kvm/x86.c

@@ -4983,11 +4983,6 @@ long kvm_arch_dev_ioctl(struct file *filp,
 	return r;
 }
 
-static void wbinvd_ipi(void *garbage)
-{
-	wbinvd();
-}
-
 static bool need_emulate_wbinvd(struct kvm_vcpu *vcpu)
 {
 	return kvm_arch_has_noncoherent_dma(vcpu->kvm);
@@ -5011,8 +5006,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 		if (kvm_x86_call(has_wbinvd_exit)())
 			cpumask_set_cpu(cpu, vcpu->arch.wbinvd_dirty_mask);
 		else if (vcpu->cpu != -1 && vcpu->cpu != cpu)
-			smp_call_function_single(vcpu->cpu,
-					wbinvd_ipi, NULL, 1);
+			wbinvd_on_cpu(vcpu->cpu);
 	}
 
 	kvm_x86_call(vcpu_load)(vcpu, cpu);