KVM: MIPS: Drop partial KVM_NMI implementation

MIPS incompletely implements the KVM_NMI ioctl to supposedly perform a
CPU reset, but all it actually does is invalidate the ASIDs. It doesn't
expose the KVM_CAP_USER_NMI capability which is supposed to indicate the
presence of the KVM_NMI ioctl, and no user software actually uses it on
MIPS.

Since this is dead code that would technically need updating for GVA
page table handling in upcoming patches, remove it now. If we wanted to
implement NMI injection later it can always be done properly along with
the KVM_CAP_USER_NMI capability, and if we wanted to implement a proper
CPU reset it would be better done with a separate ioctl.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

arch/mips/kvm/mips.c

@@ -63,18 +63,6 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{NULL}
 };
 
-static int kvm_mips_reset_vcpu(struct kvm_vcpu *vcpu)
-{
-	int i;
-
-	for_each_possible_cpu(i) {
-		vcpu->arch.guest_kernel_asid[i] = 0;
-		vcpu->arch.guest_user_asid[i] = 0;
-	}
-
-	return 0;
-}
-
 /*
  * XXXKYMA: We are simulatoring a processor that has the WII bit set in
  * Config7, so we are "runnable" if interrupts are pending
@@ -1144,10 +1132,6 @@ long kvm_arch_vcpu_ioctl(struct file *filp, unsigned int ioctl,
 			return -E2BIG;
 		return kvm_mips_copy_reg_indices(vcpu, user_list->reg);
 	}
-	case KVM_NMI:
-		/* Treat the NMI as a CPU reset */
-		r = kvm_mips_reset_vcpu(vcpu);
-		break;
 	case KVM_INTERRUPT:
 		{
 			struct kvm_mips_interrupt irq;