KVM: VMX: Expose nested_vmx_allowed() to nested VMX as a non-inline

Exposing only the function allows @nested, i.e. the module param, to be
statically defined in vmx.c, ensuring we aren't unnecessarily checking
said variable in the nested code.  nested_vmx_allowed() is exposed due
to the need to verify nested support in vmx_{get,set}_nested_state().
The downside is that nested_vmx_allowed() likely won't be inlined in
vmx_{get,set}_nested_state(), but that should be a non-issue as they're
not a hot path.  Keeping vmx_{get,set}_nested_state() in vmx.c isn't a
viable option as they need access to several nested-only functions.

Signed-off-by: Sean Christopherson <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

Author: Sean Christopherson

arch/x86/kvm/vmx/vmx.c

@@ -698,6 +698,15 @@ struct shared_msr_entry *find_msr_entry(struct vcpu_vmx *vmx, u32 msr)
 	return NULL;
 }
 
+void loaded_vmcs_init(struct loaded_vmcs *loaded_vmcs)
+{
+	vmcs_clear(loaded_vmcs->vmcs);
+	if (loaded_vmcs->shadow_vmcs && loaded_vmcs->launched)
+		vmcs_clear(loaded_vmcs->shadow_vmcs);
+	loaded_vmcs->cpu = -1;
+	loaded_vmcs->launched = 0;
+}
+
 #ifdef CONFIG_KEXEC_CORE
 /*
  * This bitmap is used to indicate whether the vmclear
@@ -1722,7 +1731,7 @@ static u64 vmx_write_l1_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
  * all guests if the "nested" module option is off, and can also be disabled
  * for a single guest by disabling its VMX cpuid bit.
  */
-static inline bool nested_vmx_allowed(struct kvm_vcpu *vcpu)
+bool nested_vmx_allowed(struct kvm_vcpu *vcpu)
 {
 	return nested && guest_cpuid_has(vcpu, X86_FEATURE_VMX);
 }

arch/x86/kvm/vmx/vmx.h

@@ -267,6 +267,7 @@ struct kvm_vmx {
 	spinlock_t ept_pointer_lock;
 };
 
+bool nested_vmx_allowed(struct kvm_vcpu *vcpu);
 void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu);
 void vmx_vcpu_put(struct kvm_vcpu *vcpu);
 int allocate_vpid(void);