11844 add rdmsr utility
Reviewed by: Dan McDonald <danmcd@joyent.com>

*** 22,32 ****
  /*
   * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  /*
!  * Copyright (c) 2012, Joyent, Inc.  All rights reserved.
   */
  
  #ifndef _SYS_CPUID_DRV_H
  #define _SYS_CPUID_DRV_H
  
--- 22,32 ----
  /*
   * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  /*
!  * Copyright 2019 Joyent, Inc.
   */
  
  #ifndef _SYS_CPUID_DRV_H
  #define _SYS_CPUID_DRV_H
  
*** 62,77 ****
--- 62,83 ----
   * ioctl numbers: not an exported interface
   */
  #define CPUID_IOC               (('c'<<24)|('i'<<16)|('d'<<8))
  
  #define CPUID_GET_HWCAP         (CPUID_IOC|0)
+ #define CPUID_RDMSR             (CPUID_IOC|1)
  
  struct cpuid_get_hwcap {
          char *cgh_archname;
          uint_t cgh_hwcap[2];
  };
  
+ struct cpuid_rdmsr {
+         uint64_t cr_msr_nr;
+         uint64_t cr_msr_val;
+ };
+ 
  #if defined(_SYSCALL32_IMPL)
  
  #include <sys/types32.h>
  
  struct cpuid_get_hwcap32 {