KVM: x86: Use more verbose names for mem encrypt kvm_x86_ops hooks

Use slightly more verbose names for the so called "memory encrypt",
a.k.a. "mem enc", kvm_x86_ops hooks to bridge the gap between the current
super short kvm_x86_ops names and SVM's more verbose, but non-conforming
names.  This is a step toward using kvm-x86-ops.h with KVM_X86_CVM_OP()
to fill svm_x86_ops.

Opportunistically rename mem_enc_op() to mem_enc_ioctl() to better
reflect its true nature, as it really is a full fledged ioctl() of its
own.  Ideally, the hook would be named confidential_vm_ioctl() or so, as
the ioctl() is a gateway to more than just memory encryption, and because
its underlying purpose to support Confidential VMs, which can be provided
without memory encryption, e.g. if the TCB of the guest includes the host
kernel but not host userspace, or by isolation in hardware without
encrypting memory.  But, diverging from KVM_MEMORY_ENCRYPT_OP even
further is undeseriable, and short of creating alises for all related
ioctl()s, which introduces a different flavor of divergence, KVM is stuck
with the nomenclature.

Defer renaming SVM's functions to a future commit as there are additional
changes needed to make SVM fully conforming and to match reality (looking
at you, svm_vm_copy_asid_from()).

No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220128005208.4008533-20-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm-x86-ops.h

@@ -112,9 +112,9 @@ KVM_X86_OP(smi_allowed)
 KVM_X86_OP(enter_smm)
 KVM_X86_OP(leave_smm)
 KVM_X86_OP(enable_smi_window)
-KVM_X86_OP_NULL(mem_enc_op)
-KVM_X86_OP_NULL(mem_enc_reg_region)
-KVM_X86_OP_NULL(mem_enc_unreg_region)
+KVM_X86_OP_NULL(mem_enc_ioctl)
+KVM_X86_OP_NULL(mem_enc_register_region)
+KVM_X86_OP_NULL(mem_enc_unregister_region)
 KVM_X86_OP_NULL(vm_copy_enc_context_from)
 KVM_X86_OP_NULL(vm_move_enc_context_from)
 KVM_X86_OP(get_msr_feature)

arch/x86/include/asm/kvm_host.h

@@ -1476,9 +1476,9 @@ struct kvm_x86_ops {
 	int (*leave_smm)(struct kvm_vcpu *vcpu, const char *smstate);
 	void (*enable_smi_window)(struct kvm_vcpu *vcpu);
 
-	int (*mem_enc_op)(struct kvm *kvm, void __user *argp);
-	int (*mem_enc_reg_region)(struct kvm *kvm, struct kvm_enc_region *argp);
-	int (*mem_enc_unreg_region)(struct kvm *kvm, struct kvm_enc_region *argp);
+	int (*mem_enc_ioctl)(struct kvm *kvm, void __user *argp);
+	int (*mem_enc_register_region)(struct kvm *kvm, struct kvm_enc_region *argp);
+	int (*mem_enc_unregister_region)(struct kvm *kvm, struct kvm_enc_region *argp);
 	int (*vm_copy_enc_context_from)(struct kvm *kvm, unsigned int source_fd);
 	int (*vm_move_enc_context_from)(struct kvm *kvm, unsigned int source_fd);
 

arch/x86/kvm/svm/sev.c

@@ -1761,7 +1761,7 @@ int svm_vm_migrate_from(struct kvm *kvm, unsigned int source_fd)
 	return ret;
 }
 
-int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
+int svm_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
 {
 	struct kvm_sev_cmd sev_cmd;
 	int r;

arch/x86/kvm/svm/svm.c

@@ -4605,9 +4605,9 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.leave_smm = svm_leave_smm,
 	.enable_smi_window = svm_enable_smi_window,
 
-	.mem_enc_op = svm_mem_enc_op,
-	.mem_enc_reg_region = svm_register_enc_region,
-	.mem_enc_unreg_region = svm_unregister_enc_region,
+	.mem_enc_ioctl = svm_mem_enc_ioctl,
+	.mem_enc_register_region = svm_register_enc_region,
+	.mem_enc_unregister_region = svm_unregister_enc_region,
 
 	.vm_copy_enc_context_from = svm_vm_copy_asid_from,
 	.vm_move_enc_context_from = svm_vm_migrate_from,

arch/x86/kvm/svm/svm.h

@@ -587,7 +587,7 @@ void avic_vcpu_unblocking(struct kvm_vcpu *vcpu);
 extern unsigned int max_sev_asid;
 
 void sev_vm_destroy(struct kvm *kvm);
-int svm_mem_enc_op(struct kvm *kvm, void __user *argp);
+int svm_mem_enc_ioctl(struct kvm *kvm, void __user *argp);
 int svm_register_enc_region(struct kvm *kvm,
 			    struct kvm_enc_region *range);
 int svm_unregister_enc_region(struct kvm *kvm,

arch/x86/kvm/x86.c

@@ -6461,8 +6461,10 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		break;
 	case KVM_MEMORY_ENCRYPT_OP: {
 		r = -ENOTTY;
-		if (kvm_x86_ops.mem_enc_op)
-			r = static_call(kvm_x86_mem_enc_op)(kvm, argp);
+		if (!kvm_x86_ops.mem_enc_ioctl)
+			goto out;
+
+		r = static_call(kvm_x86_mem_enc_ioctl)(kvm, argp);
 		break;
 	}
 	case KVM_MEMORY_ENCRYPT_REG_REGION: {
@@ -6473,8 +6475,10 @@ long kvm_arch_vm_ioctl(struct file *filp,
 			goto out;
 
 		r = -ENOTTY;
-		if (kvm_x86_ops.mem_enc_reg_region)
-			r = static_call(kvm_x86_mem_enc_reg_region)(kvm, &region);
+		if (!kvm_x86_ops.mem_enc_register_region)
+			goto out;
+
+		r = static_call(kvm_x86_mem_enc_register_region)(kvm, &region);
 		break;
 	}
 	case KVM_MEMORY_ENCRYPT_UNREG_REGION: {
@@ -6485,8 +6489,10 @@ long kvm_arch_vm_ioctl(struct file *filp,
 			goto out;
 
 		r = -ENOTTY;
-		if (kvm_x86_ops.mem_enc_unreg_region)
-			r = static_call(kvm_x86_mem_enc_unreg_region)(kvm, &region);
+		if (!kvm_x86_ops.mem_enc_unregister_region)
+			goto out;
+
+		r = static_call(kvm_x86_mem_enc_unregister_region)(kvm, &region);
 		break;
 	}
 	case KVM_HYPERV_EVENTFD: {