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 <[email protected]>
  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 /* Convert real to absolute address by applying the prefix of the CPU */
  22 static inline unsigned long kvm_s390_real_to_abs(struct kvm_vcpu *vcpu,
  23                                                  unsigned long gaddr)
  24 {
  25         unsigned long prefix  = vcpu->arch.sie_block->prefix;
  26         if (gaddr < 2 * PAGE_SIZE)
  27                 gaddr += prefix;
  28         else if (gaddr >= prefix && gaddr < prefix + 2 * PAGE_SIZE)
  29                 gaddr -= prefix;
  30         return gaddr;
  31 }
  32
  33 static inline void __user *__gptr_to_uptr(struct kvm_vcpu *vcpu,
  34                                           void __user *gptr,
  35                                           int prefixing)
  36 {
  37         unsigned long gaddr = (unsigned long) gptr;
  38         unsigned long uaddr;
  39
  40         if (prefixing)
  41                 gaddr = kvm_s390_real_to_abs(vcpu, gaddr);
  42         uaddr = gmap_fault(gaddr, vcpu->arch.gmap);
  43         if (IS_ERR_VALUE(uaddr))
  44                 uaddr = -EFAULT;
  45         return (void __user *)uaddr;
  46 }
  47
  48 #define get_guest(vcpu, x, gptr)                                \
  49 ({                                                              \
  50         __typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr, 1);\
  51         int __mask = sizeof(__typeof__(*(gptr))) - 1;           \
  52         int __ret;                                              \
  53                                                                 \
  54         if (IS_ERR((void __force *)__uptr)) {                   \
  55                 __ret = PTR_ERR((void __force *)__uptr);        \
  56         } else {                                                \
  57                 BUG_ON((unsigned long)__uptr & __mask);         \
  58                 __ret = get_user(x, __uptr);                    \
  59         }                                                       \
  60         __ret;                                                  \
  61 })
  62
  63 #define put_guest(vcpu, x, gptr)                                \
  64 ({                                                              \
  65         __typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr, 1);\
  66         int __mask = sizeof(__typeof__(*(gptr))) - 1;           \
  67         int __ret;                                              \
  68                                                                 \
  69         if (IS_ERR((void __force *)__uptr)) {                   \
  70                 __ret = PTR_ERR((void __force *)__uptr);        \
  71         } else {                                                \
  72                 BUG_ON((unsigned long)__uptr & __mask);         \
  73                 __ret = put_user(x, __uptr);                    \
  74         }                                                       \
  75         __ret;                                                  \
  76 })
  77
  78 static inline int __copy_guest(struct kvm_vcpu *vcpu, unsigned long to,
  79                                unsigned long from, unsigned long len,
  80                                int to_guest, int prefixing)
  81 {
  82         unsigned long _len, rc;
  83         void __user *uptr;
  84
  85         while (len) {
  86                 uptr = to_guest ? (void __user *)to : (void __user *)from;
  87                 uptr = __gptr_to_uptr(vcpu, uptr, prefixing);
  88                 if (IS_ERR((void __force *)uptr))
  89                         return -EFAULT;
  90                 _len = PAGE_SIZE - ((unsigned long)uptr & (PAGE_SIZE - 1));
  91                 _len = min(_len, len);
  92                 if (to_guest)
  93                         rc = copy_to_user((void __user *) uptr, (void *)from, _len);
  94                 else
  95                         rc = copy_from_user((void *)to, (void __user *)uptr, _len);
  96                 if (rc)
  97                         return -EFAULT;
  98                 len -= _len;
  99                 from += _len;
 100                 to += _len;
 101         }
 102         return 0;
 103 }
 104
 105 #define copy_to_guest(vcpu, to, from, size) \
 106         __copy_guest(vcpu, to, (unsigned long)from, size, 1, 1)
 107 #define copy_from_guest(vcpu, to, from, size) \
 108         __copy_guest(vcpu, (unsigned long)to, from, size, 0, 1)
 109 #define copy_to_guest_absolute(vcpu, to, from, size) \
 110         __copy_guest(vcpu, to, (unsigned long)from, size, 1, 0)
 111 #define copy_from_guest_absolute(vcpu, to, from, size) \
 112         __copy_guest(vcpu, (unsigned long)to, from, size, 0, 0)
 113
 114 #endif /* __KVM_S390_GACCESS_H */