KVM: nVMX: Skip IBPB when temporarily switching between vmcs01 and vmcs02

Skip the Indirect Branch Prediction Barrier that is triggered on a VMCS
switch when temporarily loading vmcs02 to synchronize it to vmcs12, i.e.
give copy_vmcs02_to_vmcs12_rare() the same treatment as
vmx_switch_vmcs().

Make vmx_vcpu_load() static now that it's only referenced within vmx.c.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200506235850.22600-3-sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/nested.c

@@ -3910,12 +3910,12 @@ static void copy_vmcs02_to_vmcs12_rare(struct kvm_vcpu *vcpu,
 
 	cpu = get_cpu();
 	vmx->loaded_vmcs = &vmx->nested.vmcs02;
-	vmx_vcpu_load(&vmx->vcpu, cpu);
+	vmx_vcpu_load_vmcs(vcpu, cpu, &vmx->vmcs01);
 
 	sync_vmcs02_to_vmcs12_rare(vcpu, vmcs12);
 
 	vmx->loaded_vmcs = &vmx->vmcs01;
-	vmx_vcpu_load(&vmx->vcpu, cpu);
+	vmx_vcpu_load_vmcs(vcpu, cpu, &vmx->nested.vmcs02);
 	put_cpu();
 }
 

arch/x86/kvm/vmx/vmx.c

@@ -1383,7 +1383,7 @@ void vmx_vcpu_load_vmcs(struct kvm_vcpu *vcpu, int cpu,
  * Switches to specified vcpu, until a matching vcpu_put(), but assumes
  * vcpu mutex is already taken.
  */
-void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
+static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 

arch/x86/kvm/vmx/vmx.h

@@ -322,7 +322,6 @@ struct kvm_vmx {
 bool nested_vmx_allowed(struct kvm_vcpu *vcpu);
 void vmx_vcpu_load_vmcs(struct kvm_vcpu *vcpu, int cpu,
 			struct loaded_vmcs *buddy);
-void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu);
 int allocate_vpid(void);
 void free_vpid(int vpid);
 void vmx_set_constant_host_state(struct vcpu_vmx *vmx);