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/*
* access guest memory
*
* Copyright IBM Corp. 2008, 2014
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License (version 2 only)
* as published by the Free Software Foundation.
*
* Author(s): Carsten Otte <cotte@de.ibm.com>
*/
#ifndef __KVM_S390_GACCESS_H
#define __KVM_S390_GACCESS_H
#include <linux/compiler.h>
#include <linux/kvm_host.h>
#include <linux/uaccess.h>
#include <linux/ptrace.h>
#include "kvm-s390.h"
/* Convert real to absolute address by applying the prefix of the CPU */
static inline unsigned long kvm_s390_real_to_abs(struct kvm_vcpu *vcpu,
unsigned long gaddr)
{
unsigned long prefix = vcpu->arch.sie_block->prefix;
if (gaddr < 2 * PAGE_SIZE)
gaddr += prefix;
else if (gaddr >= prefix && gaddr < prefix + 2 * PAGE_SIZE)
gaddr -= prefix;
return gaddr;
}
/**
* kvm_s390_logical_to_effective - convert guest logical to effective address
* @vcpu: guest virtual cpu
* @ga: guest logical address
*
* Convert a guest vcpu logical address to a guest vcpu effective address by
* applying the rules of the vcpu's addressing mode defined by PSW bits 31
* and 32 (extendended/basic addressing mode).
*
* Depending on the vcpu's addressing mode the upper 40 bits (24 bit addressing
* mode), 33 bits (31 bit addressing mode) or no bits (64 bit addressing mode)
* of @ga will be zeroed and the remaining bits will be returned.
*/
static inline unsigned long kvm_s390_logical_to_effective(struct kvm_vcpu *vcpu,
unsigned long ga)
{
psw_t *psw = &vcpu->arch.sie_block->gpsw;
if (psw_bits(*psw).eaba == PSW_AMODE_64BIT)
return ga;
if (psw_bits(*psw).eaba == PSW_AMODE_31BIT)
return ga & ((1UL << 31) - 1);
return ga & ((1UL << 24) - 1);
}
static inline void __user *__gptr_to_uptr(struct kvm_vcpu *vcpu,
void __user *gptr,
int prefixing)
{
unsigned long gaddr = (unsigned long) gptr;
unsigned long uaddr;
if (prefixing)
gaddr = kvm_s390_real_to_abs(vcpu, gaddr);
uaddr = gmap_fault(gaddr, vcpu->arch.gmap);
if (IS_ERR_VALUE(uaddr))
uaddr = -EFAULT;
return (void __user *)uaddr;
}
#define get_guest(vcpu, x, gptr) \
({ \
__typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr, 1);\
int __mask = sizeof(__typeof__(*(gptr))) - 1; \
int __ret; \
\
if (IS_ERR((void __force *)__uptr)) { \
__ret = PTR_ERR((void __force *)__uptr); \
} else { \
BUG_ON((unsigned long)__uptr & __mask); \
__ret = get_user(x, __uptr); \
} \
__ret; \
})
#define put_guest(vcpu, x, gptr) \
({ \
__typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr, 1);\
int __mask = sizeof(__typeof__(*(gptr))) - 1; \
int __ret; \
\
if (IS_ERR((void __force *)__uptr)) { \
__ret = PTR_ERR((void __force *)__uptr); \
} else { \
BUG_ON((unsigned long)__uptr & __mask); \
__ret = put_user(x, __uptr); \
} \
__ret; \
})
static inline int __copy_guest(struct kvm_vcpu *vcpu, unsigned long to,
unsigned long from, unsigned long len,
int to_guest, int prefixing)
{
unsigned long _len, rc;
void __user *uptr;
while (len) {
uptr = to_guest ? (void __user *)to : (void __user *)from;
uptr = __gptr_to_uptr(vcpu, uptr, prefixing);
if (IS_ERR((void __force *)uptr))
return -EFAULT;
_len = PAGE_SIZE - ((unsigned long)uptr & (PAGE_SIZE - 1));
_len = min(_len, len);
if (to_guest)
rc = copy_to_user((void __user *) uptr, (void *)from, _len);
else
rc = copy_from_user((void *)to, (void __user *)uptr, _len);
if (rc)
return -EFAULT;
len -= _len;
from += _len;
to += _len;
}
return 0;
}
#define copy_to_guest(vcpu, to, from, size) \
__copy_guest(vcpu, to, (unsigned long)from, size, 1, 1)
#define copy_from_guest(vcpu, to, from, size) \
__copy_guest(vcpu, (unsigned long)to, from, size, 0, 1)
#define copy_to_guest_absolute(vcpu, to, from, size) \
__copy_guest(vcpu, to, (unsigned long)from, size, 1, 0)
#define copy_from_guest_absolute(vcpu, to, from, size) \
__copy_guest(vcpu, (unsigned long)to, from, size, 0, 0)
/*
* put_guest_lc, read_guest_lc and write_guest_lc are guest access functions
* which shall only be used to access the lowcore of a vcpu.
* These functions should be used for e.g. interrupt handlers where no
* guest memory access protection facilities, like key or low address
* protection, are applicable.
* At a later point guest vcpu lowcore access should happen via pinned
* prefix pages, so that these pages can be accessed directly via the
* kernel mapping. All of these *_lc functions can be removed then.
*/
/**
* put_guest_lc - write a simple variable to a guest vcpu's lowcore
* @vcpu: virtual cpu
* @x: value to copy to guest
* @gra: vcpu's destination guest real address
*
* Copies a simple value from kernel space to a guest vcpu's lowcore.
* The size of the variable may be 1, 2, 4 or 8 bytes. The destination
* must be located in the vcpu's lowcore. Otherwise the result is undefined.
*
* Returns zero on success or -EFAULT on error.
*
* Note: an error indicates that either the kernel is out of memory or
* the guest memory mapping is broken. In any case the best solution
* would be to terminate the guest.
* It is wrong to inject a guest exception.
*/
#define put_guest_lc(vcpu, x, gra) \
({ \
struct kvm_vcpu *__vcpu = (vcpu); \
__typeof__(*(gra)) __x = (x); \
unsigned long __gpa; \
\
__gpa = (unsigned long)(gra); \
__gpa += __vcpu->arch.sie_block->prefix; \
kvm_write_guest(__vcpu->kvm, __gpa, &__x, sizeof(__x)); \
})
/**
* write_guest_lc - copy data from kernel space to guest vcpu's lowcore
* @vcpu: virtual cpu
* @gra: vcpu's source guest real address
* @data: source address in kernel space
* @len: number of bytes to copy
*
* Copy data from kernel space to guest vcpu's lowcore. The entire range must
* be located within the vcpu's lowcore, otherwise the result is undefined.
*
* Returns zero on success or -EFAULT on error.
*
* Note: an error indicates that either the kernel is out of memory or
* the guest memory mapping is broken. In any case the best solution
* would be to terminate the guest.
* It is wrong to inject a guest exception.
*/
static inline __must_check
int write_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
unsigned long len)
{
unsigned long gpa = gra + vcpu->arch.sie_block->prefix;
return kvm_write_guest(vcpu->kvm, gpa, data, len);
}
/**
* read_guest_lc - copy data from guest vcpu's lowcore to kernel space
* @vcpu: virtual cpu
* @gra: vcpu's source guest real address
* @data: destination address in kernel space
* @len: number of bytes to copy
*
* Copy data from guest vcpu's lowcore to kernel space. The entire range must
* be located within the vcpu's lowcore, otherwise the result is undefined.
*
* Returns zero on success or -EFAULT on error.
*
* Note: an error indicates that either the kernel is out of memory or
* the guest memory mapping is broken. In any case the best solution
* would be to terminate the guest.
* It is wrong to inject a guest exception.
*/
static inline __must_check
int read_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
unsigned long len)
{
unsigned long gpa = gra + vcpu->arch.sie_block->prefix;
return kvm_read_guest(vcpu->kvm, gpa, data, len);
}
#endif /* __KVM_S390_GACCESS_H */
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