KVM: x86: move nested-related kvm_x86_ops to a separate struct

Clean up some of the patching of kvm_x86_ops, by moving kvm_x86_ops related to
nested virtualization into a separate struct.

As a result, these ops will always be non-NULL on VMX.  This is not a problem:

* check_nested_events is only called if is_guest_mode(vcpu) returns true

* get_nested_state treats VMXOFF state the same as nested being disabled

* set_nested_state fails if you attempt to set nested state while
  nesting is disabled

* nested_enable_evmcs could already be called on a CPU without VMX enabled
  in CPUID.

* nested_get_evmcs_version was fixed in the previous patch
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -1178,7 +1178,6 @@ struct kvm_x86_ops {
 			       struct x86_exception *exception);
 	void (*handle_exit_irqoff)(struct kvm_vcpu *vcpu);
 
-	int (*check_nested_events)(struct kvm_vcpu *vcpu);
 	void (*request_immediate_exit)(struct kvm_vcpu *vcpu);
 
 	void (*sched_in)(struct kvm_vcpu *kvm, int cpu);
@@ -1211,6 +1210,7 @@ struct kvm_x86_ops {
 
 	/* pmu operations of sub-arch */
 	const struct kvm_pmu_ops *pmu_ops;
+	const struct kvm_x86_nested_ops *nested_ops;
 
 	/*
 	 * Architecture specific hooks for vCPU blocking due to
@@ -1238,14 +1238,6 @@ struct kvm_x86_ops {
 
 	void (*setup_mce)(struct kvm_vcpu *vcpu);
 
-	int (*get_nested_state)(struct kvm_vcpu *vcpu,
-				struct kvm_nested_state __user *user_kvm_nested_state,
-				unsigned user_data_size);
-	int (*set_nested_state)(struct kvm_vcpu *vcpu,
-				struct kvm_nested_state __user *user_kvm_nested_state,
-				struct kvm_nested_state *kvm_state);
-	bool (*get_vmcs12_pages)(struct kvm_vcpu *vcpu);
-
 	int (*smi_allowed)(struct kvm_vcpu *vcpu);
 	int (*pre_enter_smm)(struct kvm_vcpu *vcpu, char *smstate);
 	int (*pre_leave_smm)(struct kvm_vcpu *vcpu, const char *smstate);
@@ -1257,16 +1249,27 @@ struct kvm_x86_ops {
 
 	int (*get_msr_feature)(struct kvm_msr_entry *entry);
 
-	int (*nested_enable_evmcs)(struct kvm_vcpu *vcpu,
-				   uint16_t *vmcs_version);
-	uint16_t (*nested_get_evmcs_version)(struct kvm_vcpu *vcpu);
-
 	bool (*need_emulation_on_page_fault)(struct kvm_vcpu *vcpu);
 
 	bool (*apic_init_signal_blocked)(struct kvm_vcpu *vcpu);
 	int (*enable_direct_tlbflush)(struct kvm_vcpu *vcpu);
 };
 
+struct kvm_x86_nested_ops {
+	int (*check_events)(struct kvm_vcpu *vcpu);
+	int (*get_state)(struct kvm_vcpu *vcpu,
+			 struct kvm_nested_state __user *user_kvm_nested_state,
+			 unsigned user_data_size);
+	int (*set_state)(struct kvm_vcpu *vcpu,
+			 struct kvm_nested_state __user *user_kvm_nested_state,
+			 struct kvm_nested_state *kvm_state);
+	bool (*get_vmcs12_pages)(struct kvm_vcpu *vcpu);
+
+	int (*enable_evmcs)(struct kvm_vcpu *vcpu,
+			    uint16_t *vmcs_version);
+	uint16_t (*get_evmcs_version)(struct kvm_vcpu *vcpu);
+};
+
 struct kvm_x86_init_ops {
 	int (*cpu_has_kvm_support)(void);
 	int (*disabled_by_bios)(void);

arch/x86/kvm/hyperv.c

@@ -1799,8 +1799,8 @@ int kvm_vcpu_ioctl_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid,
 	};
 	int i, nent = ARRAY_SIZE(cpuid_entries);
 
-	if (kvm_x86_ops.nested_get_evmcs_version)
-		evmcs_ver = kvm_x86_ops.nested_get_evmcs_version(vcpu);
+	if (kvm_x86_ops.nested_ops->get_evmcs_version)
+		evmcs_ver = kvm_x86_ops.nested_ops->get_evmcs_version(vcpu);
 
 	/* Skip NESTED_FEATURES if eVMCS is not supported */
 	if (!evmcs_ver)

arch/x86/kvm/svm/nested.c

@@ -784,7 +784,7 @@ static bool nested_exit_on_intr(struct vcpu_svm *svm)
 	return (svm->nested.intercept & 1ULL);
 }
 
-int svm_check_nested_events(struct kvm_vcpu *vcpu)
+static int svm_check_nested_events(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 	bool block_nested_events =
@@ -825,3 +825,7 @@ int nested_svm_exit_special(struct vcpu_svm *svm)
 
 	return NESTED_EXIT_CONTINUE;
 }
+
+struct kvm_x86_nested_ops svm_nested_ops = {
+	.check_events = svm_check_nested_events,
+};

arch/x86/kvm/svm/svm.c

@@ -3902,9 +3902,9 @@ static bool svm_apic_init_signal_blocked(struct kvm_vcpu *vcpu)
 	/*
 	 * TODO: Last condition latch INIT signals on vCPU when
 	 * vCPU is in guest-mode and vmcb12 defines intercept on INIT.
-	 * To properly emulate the INIT intercept, SVM should implement
-	 * kvm_x86_ops.check_nested_events() and call nested_svm_vmexit()
-	 * there if an INIT signal is pending.
+	 * To properly emulate the INIT intercept,
+	 * svm_check_nested_events() should call nested_svm_vmexit()
+	 * if an INIT signal is pending.
 	 */
 	return !gif_set(svm) ||
 		   (svm->vmcb->control.intercept & (1ULL << INTERCEPT_INIT));
@@ -4032,6 +4032,8 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.sched_in = svm_sched_in,
 
 	.pmu_ops = &amd_pmu_ops,
+	.nested_ops = &svm_nested_ops,
+
 	.deliver_posted_interrupt = svm_deliver_avic_intr,
 	.dy_apicv_has_pending_interrupt = svm_dy_apicv_has_pending_interrupt,
 	.update_pi_irte = svm_update_pi_irte,
@@ -4046,14 +4048,9 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.mem_enc_reg_region = svm_register_enc_region,
 	.mem_enc_unreg_region = svm_unregister_enc_region,
 
-	.nested_enable_evmcs = NULL,
-	.nested_get_evmcs_version = NULL,
-
 	.need_emulation_on_page_fault = svm_need_emulation_on_page_fault,
 
 	.apic_init_signal_blocked = svm_apic_init_signal_blocked,
-
-	.check_nested_events = svm_check_nested_events,
 };
 
 static struct kvm_x86_init_ops svm_init_ops __initdata = {

arch/x86/kvm/svm/svm.h

@@ -398,9 +398,10 @@ int nested_svm_exit_handled(struct vcpu_svm *svm);
 int nested_svm_check_permissions(struct vcpu_svm *svm);
 int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
 			       bool has_error_code, u32 error_code);
-int svm_check_nested_events(struct kvm_vcpu *vcpu);
 int nested_svm_exit_special(struct vcpu_svm *svm);
 
+extern struct kvm_x86_nested_ops svm_nested_ops;
+
 /* avic.c */
 
 #define AVIC_LOGICAL_ID_ENTRY_GUEST_PHYSICAL_ID_MASK	(0xFF)

arch/x86/kvm/vmx/nested.c

@@ -6440,12 +6440,14 @@ __init int nested_vmx_hardware_setup(struct kvm_x86_ops *ops,
 	exit_handlers[EXIT_REASON_INVVPID]	= handle_invvpid;
 	exit_handlers[EXIT_REASON_VMFUNC]	= handle_vmfunc;
 
-	ops->check_nested_events = vmx_check_nested_events;
-	ops->get_nested_state = vmx_get_nested_state;
-	ops->set_nested_state = vmx_set_nested_state;
-	ops->get_vmcs12_pages = nested_get_vmcs12_pages;
-	ops->nested_enable_evmcs = nested_enable_evmcs;
-	ops->nested_get_evmcs_version = nested_get_evmcs_version;
-
 	return 0;
 }
+
+struct kvm_x86_nested_ops vmx_nested_ops = {
+	.check_events = vmx_check_nested_events,
+	.get_state = vmx_get_nested_state,
+	.set_state = vmx_set_nested_state,
+	.get_vmcs12_pages = nested_get_vmcs12_pages,
+	.enable_evmcs = nested_enable_evmcs,
+	.get_evmcs_version = nested_get_evmcs_version,
+};

arch/x86/kvm/vmx/nested.h

@@ -278,4 +278,6 @@ static inline bool nested_cr4_valid(struct kvm_vcpu *vcpu, unsigned long val)
 #define nested_guest_cr4_valid	nested_cr4_valid
 #define nested_host_cr4_valid	nested_cr4_valid
 
+extern struct kvm_x86_nested_ops vmx_nested_ops;
+
 #endif /* __KVM_X86_VMX_NESTED_H */

arch/x86/kvm/vmx/vmx.c

@@ -7862,6 +7862,7 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.post_block = vmx_post_block,
 
 	.pmu_ops = &intel_pmu_ops,
+	.nested_ops = &vmx_nested_ops,
 
 	.update_pi_irte = vmx_update_pi_irte,
 
@@ -7877,12 +7878,6 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.pre_leave_smm = vmx_pre_leave_smm,
 	.enable_smi_window = enable_smi_window,
 
-	.check_nested_events = NULL,
-	.get_nested_state = NULL,
-	.set_nested_state = NULL,
-	.get_vmcs12_pages = NULL,
-	.nested_enable_evmcs = NULL,
-	.nested_get_evmcs_version = NULL,
 	.need_emulation_on_page_fault = vmx_need_emulation_on_page_fault,
 	.apic_init_signal_blocked = vmx_apic_init_signal_blocked,
 };

arch/x86/kvm/x86.c

@@ -3442,14 +3442,14 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		r = KVM_X2APIC_API_VALID_FLAGS;
 		break;
 	case KVM_CAP_NESTED_STATE:
-		r = kvm_x86_ops.get_nested_state ?
-			kvm_x86_ops.get_nested_state(NULL, NULL, 0) : 0;
+		r = kvm_x86_ops.nested_ops->get_state ?
+			kvm_x86_ops.nested_ops->get_state(NULL, NULL, 0) : 0;
 		break;
 	case KVM_CAP_HYPERV_DIRECT_TLBFLUSH:
 		r = kvm_x86_ops.enable_direct_tlbflush != NULL;
 		break;
 	case KVM_CAP_HYPERV_ENLIGHTENED_VMCS:
-		r = kvm_x86_ops.nested_enable_evmcs != NULL;
+		r = kvm_x86_ops.nested_ops->enable_evmcs != NULL;
 		break;
 	default:
 		break;
@@ -4235,9 +4235,9 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
 		return kvm_hv_activate_synic(vcpu, cap->cap ==
 					     KVM_CAP_HYPERV_SYNIC2);
 	case KVM_CAP_HYPERV_ENLIGHTENED_VMCS:
-		if (!kvm_x86_ops.nested_enable_evmcs)
+		if (!kvm_x86_ops.nested_ops->enable_evmcs)
 			return -ENOTTY;
-		r = kvm_x86_ops.nested_enable_evmcs(vcpu, &vmcs_version);
+		r = kvm_x86_ops.nested_ops->enable_evmcs(vcpu, &vmcs_version);
 		if (!r) {
 			user_ptr = (void __user *)(uintptr_t)cap->args[0];
 			if (copy_to_user(user_ptr, &vmcs_version,
@@ -4552,7 +4552,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 		u32 user_data_size;
 
 		r = -EINVAL;
-		if (!kvm_x86_ops.get_nested_state)
+		if (!kvm_x86_ops.nested_ops->get_state)
 			break;
 
 		BUILD_BUG_ON(sizeof(user_data_size) != sizeof(user_kvm_nested_state->size));
@@ -4560,7 +4560,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 		if (get_user(user_data_size, &user_kvm_nested_state->size))
 			break;
 
-		r = kvm_x86_ops.get_nested_state(vcpu, user_kvm_nested_state,
+		r = kvm_x86_ops.nested_ops->get_state(vcpu, user_kvm_nested_state,
 						     user_data_size);
 		if (r < 0)
 			break;
@@ -4582,7 +4582,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 		int idx;
 
 		r = -EINVAL;
-		if (!kvm_x86_ops.set_nested_state)
+		if (!kvm_x86_ops.nested_ops->set_state)
 			break;
 
 		r = -EFAULT;
@@ -4604,7 +4604,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 			break;
 
 		idx = srcu_read_lock(&vcpu->kvm->srcu);
-		r = kvm_x86_ops.set_nested_state(vcpu, user_kvm_nested_state, &kvm_state);
+		r = kvm_x86_ops.nested_ops->set_state(vcpu, user_kvm_nested_state, &kvm_state);
 		srcu_read_unlock(&vcpu->kvm->srcu, idx);
 		break;
 	}
@@ -7700,7 +7700,7 @@ static int inject_pending_event(struct kvm_vcpu *vcpu)
 	 * from L2 to L1.
 	 */
 	if (is_guest_mode(vcpu)) {
-		r = kvm_x86_ops.check_nested_events(vcpu);
+		r = kvm_x86_ops.nested_ops->check_events(vcpu);
 		if (r != 0)
 			return r;
 	}
@@ -7762,7 +7762,7 @@ static int inject_pending_event(struct kvm_vcpu *vcpu)
 		 * KVM_REQ_EVENT only on certain events and not unconditionally?
 		 */
 		if (is_guest_mode(vcpu)) {
-			r = kvm_x86_ops.check_nested_events(vcpu);
+			r = kvm_x86_ops.nested_ops->check_events(vcpu);
 			if (r != 0)
 				return r;
 		}
@@ -8185,7 +8185,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 
 	if (kvm_request_pending(vcpu)) {
 		if (kvm_check_request(KVM_REQ_GET_VMCS12_PAGES, vcpu)) {
-			if (unlikely(!kvm_x86_ops.get_vmcs12_pages(vcpu))) {
+			if (unlikely(!kvm_x86_ops.nested_ops->get_vmcs12_pages(vcpu))) {
 				r = 0;
 				goto out;
 			}
@@ -8528,7 +8528,7 @@ static inline int vcpu_block(struct kvm *kvm, struct kvm_vcpu *vcpu)
 static inline bool kvm_vcpu_running(struct kvm_vcpu *vcpu)
 {
 	if (is_guest_mode(vcpu))
-		kvm_x86_ops.check_nested_events(vcpu);
+		kvm_x86_ops.nested_ops->check_events(vcpu);
 
 	return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE &&
 		!vcpu->arch.apf.halted);