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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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228b82211b
Saves repeating "(void __force *)__uptr" but it's less clear. Using the output of PTR_RET() to determine the error rather than just testing IS_ERR() is odd. For example, I *assume* __gptr_to_uptr() never returns NULL? Because the __ret would be 0 for the old code. The new version is clearer, IMHO: it would try to get_user() on that address. If you hate this variant, I can just s/PTR_RET/PTR_ERR_OR_ZERO/ instead. Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
108 lines
2.9 KiB
C
108 lines
2.9 KiB
C
/*
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* access guest memory
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*
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* Copyright IBM Corp. 2008, 2009
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License (version 2 only)
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* as published by the Free Software Foundation.
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*
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* Author(s): Carsten Otte <cotte@de.ibm.com>
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*/
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#ifndef __KVM_S390_GACCESS_H
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#define __KVM_S390_GACCESS_H
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#include <linux/compiler.h>
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#include <linux/kvm_host.h>
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#include <asm/uaccess.h>
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#include "kvm-s390.h"
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static inline void __user *__gptr_to_uptr(struct kvm_vcpu *vcpu,
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void __user *gptr,
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int prefixing)
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{
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unsigned long prefix = vcpu->arch.sie_block->prefix;
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unsigned long gaddr = (unsigned long) gptr;
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unsigned long uaddr;
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if (prefixing) {
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if (gaddr < 2 * PAGE_SIZE)
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gaddr += prefix;
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else if ((gaddr >= prefix) && (gaddr < prefix + 2 * PAGE_SIZE))
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gaddr -= prefix;
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}
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uaddr = gmap_fault(gaddr, vcpu->arch.gmap);
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if (IS_ERR_VALUE(uaddr))
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uaddr = -EFAULT;
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return (void __user *)uaddr;
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}
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#define get_guest(vcpu, x, gptr) \
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({ \
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__typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr, 1);\
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int __mask = sizeof(__typeof__(*(gptr))) - 1; \
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int __ret; \
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\
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if (IS_ERR((void __force *)__uptr)) { \
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__ret = PTR_ERR((void __force *)__uptr); \
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} else { \
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BUG_ON((unsigned long)__uptr & __mask); \
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__ret = get_user(x, __uptr); \
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} \
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__ret; \
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})
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#define put_guest(vcpu, x, gptr) \
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({ \
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__typeof__(gptr) __uptr = __gptr_to_uptr(vcpu, gptr, 1);\
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int __mask = sizeof(__typeof__(*(gptr))) - 1; \
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int __ret; \
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\
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if (IS_ERR((void __force *)__uptr)) { \
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__ret = PTR_ERR((void __force *)__uptr); \
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} else { \
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BUG_ON((unsigned long)__uptr & __mask); \
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__ret = put_user(x, __uptr); \
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} \
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__ret; \
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})
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static inline int __copy_guest(struct kvm_vcpu *vcpu, unsigned long to,
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unsigned long from, unsigned long len,
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int to_guest, int prefixing)
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{
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unsigned long _len, rc;
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void __user *uptr;
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while (len) {
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uptr = to_guest ? (void __user *)to : (void __user *)from;
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uptr = __gptr_to_uptr(vcpu, uptr, prefixing);
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if (IS_ERR((void __force *)uptr))
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return -EFAULT;
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_len = PAGE_SIZE - ((unsigned long)uptr & (PAGE_SIZE - 1));
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_len = min(_len, len);
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if (to_guest)
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rc = copy_to_user((void __user *) uptr, (void *)from, _len);
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else
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rc = copy_from_user((void *)to, (void __user *)uptr, _len);
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if (rc)
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return -EFAULT;
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len -= _len;
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from += _len;
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to += _len;
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}
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return 0;
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}
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#define copy_to_guest(vcpu, to, from, size) \
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__copy_guest(vcpu, to, (unsigned long)from, size, 1, 1)
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#define copy_from_guest(vcpu, to, from, size) \
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__copy_guest(vcpu, (unsigned long)to, from, size, 0, 1)
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#define copy_to_guest_absolute(vcpu, to, from, size) \
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__copy_guest(vcpu, to, (unsigned long)from, size, 1, 0)
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#define copy_from_guest_absolute(vcpu, to, from, size) \
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__copy_guest(vcpu, (unsigned long)to, from, size, 0, 0)
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#endif /* __KVM_S390_GACCESS_H */
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