arch/s390/kvm/gaccess.h

   1 /*
   2  * access guest memory
   3  *
   4  * Copyright IBM Corp. 2008, 2009
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License (version 2 only)
   8  * as published by the Free Software Foundation.
   9  *
  10  *    Author(s): Carsten Otte <cotte@de.ibm.com>
  11  */
  12
  13 #ifndef __KVM_S390_GACCESS_H
  14 #define __KVM_S390_GACCESS_H
  15
  16 #include <linux/compiler.h>
  17 #include <linux/kvm_host.h>
  18 #include <asm/uaccess.h>
  19 #include "kvm-s390.h"
  20
  21 static inline void __user *__gptr_to_uptr(struct kvm_vcpu *vcpu,
  22                                           void __user *gptr,
  23                                           int prefixing)
  24 {
  25         unsigned long prefix  = vcpu->arch.sie_block->prefix;
  26         unsigned long gaddr = (unsigned long) gptr;
  27         unsigned long uaddr;
  28
  29         if (prefixing) {
  30                 if (gaddr < 2 * PAGE_SIZE)
  31                         gaddr += prefix;
  32                 else if ((gaddr >= prefix) && (gaddr < prefix + 2 * PAGE_SIZE))
  33                         gaddr -= prefix;
  34         }
  35         uaddr = gmap_fault(gaddr, vcpu->arch.gmap);
  36         if (IS_ERR_VALUE(uaddr))
  37                 uaddr = -EFAULT;
  38         return (void __user *)uaddr;
  39 }
  40
  41 #define get_guest(vcpu, x, gptr)                                \
  42 ({                                                              \
  43         __typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr, 1);\
  44         int __mask = sizeof(__typeof__(*(gptr))) - 1;           \
  45         int __ret;                                              \
  46                                                                 \
  47         if (IS_ERR((void __force *)__uptr)) {                   \
  48                 __ret = PTR_ERR((void __force *)__uptr);        \
  49         } else {                                                \
  50                 BUG_ON((unsigned long)__uptr & __mask);         \
  51                 __ret = get_user(x, __uptr);                    \
  52         }                                                       \
  53         __ret;                                                  \
  54 })
  55
  56 #define put_guest(vcpu, x, gptr)                                \
  57 ({                                                              \
  58         __typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr, 1);\
  59         int __mask = sizeof(__typeof__(*(gptr))) - 1;           \
  60         int __ret;                                              \
  61                                                                 \
  62         if (IS_ERR((void __force *)__uptr)) {                   \
  63                 __ret = PTR_ERR((void __force *)__uptr);        \
  64         } else {                                                \
  65                 BUG_ON((unsigned long)__uptr & __mask);         \
  66                 __ret = put_user(x, __uptr);                    \
  67         }                                                       \
  68         __ret;                                                  \
  69 })
  70
  71 static inline int __copy_guest(struct kvm_vcpu *vcpu, unsigned long to,
  72                                unsigned long from, unsigned long len,
  73                                int to_guest, int prefixing)
  74 {
  75         unsigned long _len, rc;
  76         void __user *uptr;
  77
  78         while (len) {
  79                 uptr = to_guest ? (void __user *)to : (void __user *)from;
  80                 uptr = __gptr_to_uptr(vcpu, uptr, prefixing);
  81                 if (IS_ERR((void __force *)uptr))
  82                         return -EFAULT;
  83                 _len = PAGE_SIZE - ((unsigned long)uptr & (PAGE_SIZE - 1));
  84                 _len = min(_len, len);
  85                 if (to_guest)
  86                         rc = copy_to_user((void __user *) uptr, (void *)from, _len);
  87                 else
  88                         rc = copy_from_user((void *)to, (void __user *)uptr, _len);
  89                 if (rc)
  90                         return -EFAULT;
  91                 len -= _len;
  92                 from += _len;
  93                 to += _len;
  94         }
  95         return 0;
  96 }
  97
  98 #define copy_to_guest(vcpu, to, from, size) \
  99         __copy_guest(vcpu, to, (unsigned long)from, size, 1, 1)
 100 #define copy_from_guest(vcpu, to, from, size) \
 101         __copy_guest(vcpu, (unsigned long)to, from, size, 0, 1)
 102 #define copy_to_guest_absolute(vcpu, to, from, size) \
 103         __copy_guest(vcpu, to, (unsigned long)from, size, 1, 0)
 104 #define copy_from_guest_absolute(vcpu, to, from, size) \
 105         __copy_guest(vcpu, (unsigned long)to, from, size, 0, 0)
 106
 107 #endif /* __KVM_S390_GACCESS_H */