KVM: s390: add lowcore access functions
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. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
Heiko Carstens
Christian Borntraeger
parent
1b0462e574
commit
d95fb12ff4
|
|
@ -1,7 +1,7 @@
|
|||
/*
|
||||
* access guest memory
|
||||
*
|
||||
* Copyright IBM Corp. 2008, 2009
|
||||
* 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)
|
||||
|
|
@ -15,7 +15,8 @@
|
|||
|
||||
#include <linux/compiler.h>
|
||||
#include <linux/kvm_host.h>
|
||||
#include <asm/uaccess.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 */
|
||||
|
|
@ -136,4 +137,94 @@ static inline int __copy_guest(struct kvm_vcpu *vcpu, unsigned long to,
|
|||
#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 */
|
||||
|
|
|
|||
Loading…
Reference in New Issue