KVM: x86: Move init-only kvm_x86_ops to separate struct

Move the kvm_x86_ops functions that are used only within the scope of
kvm_init() into a separate struct, kvm_x86_init_ops.  In addition to
identifying the init-only functions without restorting to code comments,
this also sets the stage for waiting until after ->hardware_setup() to
set kvm_x86_ops.  Setting kvm_x86_ops after ->hardware_setup() is
desirable as many of the hooks are not usable until ->hardware_setup()
completes.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200321202603.19355-3-sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -1054,12 +1054,8 @@ static inline u16 kvm_lapic_irq_dest_mode(bool dest_mode_logical)
 }
 
 struct kvm_x86_ops {
-	int (*cpu_has_kvm_support)(void);          /* __init */
-	int (*disabled_by_bios)(void);             /* __init */
 	int (*hardware_enable)(void);
 	void (*hardware_disable)(void);
-	int (*check_processor_compatibility)(void);/* __init */
-	int (*hardware_setup)(void);               /* __init */
 	void (*hardware_unsetup)(void);            /* __exit */
 	bool (*cpu_has_accelerated_tpr)(void);
 	bool (*has_emulated_msr)(int index);
@@ -1260,6 +1256,15 @@ struct kvm_x86_ops {
 	int (*enable_direct_tlbflush)(struct kvm_vcpu *vcpu);
 };
 
+struct kvm_x86_init_ops {
+	int (*cpu_has_kvm_support)(void);
+	int (*disabled_by_bios)(void);
+	int (*check_processor_compatibility)(void);
+	int (*hardware_setup)(void);
+
+	struct kvm_x86_ops *runtime_ops;
+};
+
 struct kvm_arch_async_pf {
 	u32 token;
 	gfn_t gfn;

arch/x86/kvm/svm.c

@@ -7354,11 +7354,7 @@ static void svm_pre_update_apicv_exec_ctrl(struct kvm *kvm, bool activate)
 }
 
 static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
-	.cpu_has_kvm_support = has_svm,
-	.disabled_by_bios = is_disabled,
-	.hardware_setup = svm_hardware_setup,
 	.hardware_unsetup = svm_hardware_teardown,
-	.check_processor_compatibility = svm_check_processor_compat,
 	.hardware_enable = svm_hardware_enable,
 	.hardware_disable = svm_hardware_disable,
 	.cpu_has_accelerated_tpr = svm_cpu_has_accelerated_tpr,
@@ -7483,9 +7479,18 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
 	.check_nested_events = svm_check_nested_events,
 };
 
+static struct kvm_x86_init_ops svm_init_ops __initdata = {
+	.cpu_has_kvm_support = has_svm,
+	.disabled_by_bios = is_disabled,
+	.hardware_setup = svm_hardware_setup,
+	.check_processor_compatibility = svm_check_processor_compat,
+
+	.runtime_ops = &svm_x86_ops,
+};
+
 static int __init svm_init(void)
 {
-	return kvm_init(&svm_x86_ops, sizeof(struct vcpu_svm),
+	return kvm_init(&svm_init_ops, sizeof(struct vcpu_svm),
 			__alignof__(struct vcpu_svm), THIS_MODULE);
 }
 

arch/x86/kvm/vmx/vmx.c

@@ -7836,11 +7836,8 @@ static bool vmx_check_apicv_inhibit_reasons(ulong bit)
 }
 
 static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
-	.cpu_has_kvm_support = cpu_has_kvm_support,
-	.disabled_by_bios = vmx_disabled_by_bios,
-	.hardware_setup = hardware_setup,
 	.hardware_unsetup = hardware_unsetup,
-	.check_processor_compatibility = vmx_check_processor_compat,
+
 	.hardware_enable = hardware_enable,
 	.hardware_disable = hardware_disable,
 	.cpu_has_accelerated_tpr = report_flexpriority,
@@ -7975,6 +7972,15 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
 	.apic_init_signal_blocked = vmx_apic_init_signal_blocked,
 };
 
+static struct kvm_x86_init_ops vmx_init_ops __initdata = {
+	.cpu_has_kvm_support = cpu_has_kvm_support,
+	.disabled_by_bios = vmx_disabled_by_bios,
+	.check_processor_compatibility = vmx_check_processor_compat,
+	.hardware_setup = hardware_setup,
+
+	.runtime_ops = &vmx_x86_ops,
+};
+
 static void vmx_cleanup_l1d_flush(void)
 {
 	if (vmx_l1d_flush_pages) {
@@ -8059,7 +8065,7 @@ static int __init vmx_init(void)
 	}
 #endif
 
-	r = kvm_init(&vmx_x86_ops, sizeof(struct vcpu_vmx),
+	r = kvm_init(&vmx_init_ops, sizeof(struct vcpu_vmx),
 		     __alignof__(struct vcpu_vmx), THIS_MODULE);
 	if (r)
 		return r;

arch/x86/kvm/x86.c

@@ -7303,8 +7303,8 @@ static struct notifier_block pvclock_gtod_notifier = {
 
 int kvm_arch_init(void *opaque)
 {
+	struct kvm_x86_init_ops *ops = opaque;
 	int r;
-	struct kvm_x86_ops *ops = opaque;
 
 	if (kvm_x86_ops) {
 		printk(KERN_ERR "kvm: already loaded the other module\n");
@@ -7359,7 +7359,7 @@ int kvm_arch_init(void *opaque)
 	if (r)
 		goto out_free_percpu;
 
-	kvm_x86_ops = ops;
+	kvm_x86_ops = ops->runtime_ops;
 
 	kvm_mmu_set_mask_ptes(PT_USER_MASK, PT_ACCESSED_MASK,
 			PT_DIRTY_MASK, PT64_NX_MASK, 0,
@@ -9628,6 +9628,7 @@ void kvm_arch_hardware_disable(void)
 
 int kvm_arch_hardware_setup(void *opaque)
 {
+	struct kvm_x86_init_ops *ops = opaque;
 	int r;
 
 	rdmsrl_safe(MSR_EFER, &host_efer);
@@ -9635,7 +9636,7 @@ int kvm_arch_hardware_setup(void *opaque)
 	if (boot_cpu_has(X86_FEATURE_XSAVES))
 		rdmsrl(MSR_IA32_XSS, host_xss);
 
-	r = kvm_x86_ops->hardware_setup();
+	r = ops->hardware_setup();
 	if (r != 0)
 		return r;
 
@@ -9670,13 +9671,14 @@ void kvm_arch_hardware_unsetup(void)
 int kvm_arch_check_processor_compat(void *opaque)
 {
 	struct cpuinfo_x86 *c = &cpu_data(smp_processor_id());
+	struct kvm_x86_init_ops *ops = opaque;
 
 	WARN_ON(!irqs_disabled());
 
 	if (kvm_host_cr4_reserved_bits(c) != cr4_reserved_bits)
 		return -EIO;
 
-	return kvm_x86_ops->check_processor_compatibility();
+	return ops->check_processor_compatibility();
 }
 
 bool kvm_vcpu_is_reset_bsp(struct kvm_vcpu *vcpu)