KVM: SVM: hyper-v: placate modpost section mismatch error

modpost reports section mismatch errors/warnings:
WARNING: modpost: vmlinux.o: section mismatch in reference: svm_hv_hardware_setup (section: .text) -> (unknown) (section: .init.data)
WARNING: modpost: vmlinux.o: section mismatch in reference: svm_hv_hardware_setup (section: .text) -> (unknown) (section: .init.data)
WARNING: modpost: vmlinux.o: section mismatch in reference: svm_hv_hardware_setup (section: .text) -> (unknown) (section: .init.data)

This "(unknown) (section: .init.data)" all refer to svm_x86_ops.

Tag svm_hv_hardware_setup() with __init to fix a modpost warning as the
non-stub implementation accesses __initdata (svm_x86_ops), i.e. would
generate a use-after-free if svm_hv_hardware_setup() were actually invoked
post-init.  The helper is only called from svm_hardware_setup(), which is
also __init, i.e. lack of __init is benign other than the modpost warning.

Fixes: 1e0c7d4 ("KVM: SVM: hyper-v: Remote TLB flush for SVM")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Vineeth Pillai <viremana@linux.microsoft.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org
Cc: stable@vger.kernel.org
Reviewed-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20230222073315.9081-1-rdunlap@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Author: rddunlap

arch/x86/kvm/svm/svm_onhyperv.h

@@ -30,7 +30,7 @@ static inline void svm_hv_init_vmcb(struct vmcb *vmcb)
 		hve->hv_enlightenments_control.msr_bitmap = 1;
 }
 
-static inline void svm_hv_hardware_setup(void)
+static inline __init void svm_hv_hardware_setup(void)
 {
 	if (npt_enabled &&
 	    ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB) {
@@ -84,7 +84,7 @@ static inline void svm_hv_init_vmcb(struct vmcb *vmcb)
 {
 }
 
-static inline void svm_hv_hardware_setup(void)
+static inline __init void svm_hv_hardware_setup(void)
 {
 }