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/*
* Copyright 2012 Michael Ellerman, IBM Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/kvm_host.h>
#include <linux/kvm.h>
#include <linux/err.h>
#include <asm/uaccess.h>
#include <asm/kvm_book3s.h>
#include <asm/kvm_ppc.h>
#include <asm/hvcall.h>
#include <asm/rtas.h>
struct rtas_handler {
void (*handler)(struct kvm_vcpu *vcpu, struct rtas_args *args);
char *name;
};
static struct rtas_handler rtas_handlers[] = { };
struct rtas_token_definition {
struct list_head list;
struct rtas_handler *handler;
u64 token;
};
static int rtas_name_matches(char *s1, char *s2)
{
struct kvm_rtas_token_args args;
return !strncmp(s1, s2, sizeof(args.name));
}
static int rtas_token_undefine(struct kvm *kvm, char *name)
{
struct rtas_token_definition *d, *tmp;
lockdep_assert_held(&kvm->lock);
list_for_each_entry_safe(d, tmp, &kvm->arch.rtas_tokens, list) {
if (rtas_name_matches(d->handler->name, name)) {
list_del(&d->list);
kfree(d);
return 0;
}
}
/* It's not an error to undefine an undefined token */
return 0;
}
static int rtas_token_define(struct kvm *kvm, char *name, u64 token)
{
struct rtas_token_definition *d;
struct rtas_handler *h = NULL;
bool found;
int i;
lockdep_assert_held(&kvm->lock);
list_for_each_entry(d, &kvm->arch.rtas_tokens, list) {
if (d->token == token)
return -EEXIST;
}
found = false;
for (i = 0; i < ARRAY_SIZE(rtas_handlers); i++) {
h = &rtas_handlers[i];
if (rtas_name_matches(h->name, name)) {
found = true;
break;
}
}
if (!found)
return -ENOENT;
d = kzalloc(sizeof(*d), GFP_KERNEL);
if (!d)
return -ENOMEM;
d->handler = h;
d->token = token;
list_add_tail(&d->list, &kvm->arch.rtas_tokens);
return 0;
}
int kvm_vm_ioctl_rtas_define_token(struct kvm *kvm, void __user *argp)
{
struct kvm_rtas_token_args args;
int rc;
if (copy_from_user(&args, argp, sizeof(args)))
return -EFAULT;
mutex_lock(&kvm->lock);
if (args.token)
rc = rtas_token_define(kvm, args.name, args.token);
else
rc = rtas_token_undefine(kvm, args.name);
mutex_unlock(&kvm->lock);
return rc;
}
int kvmppc_rtas_hcall(struct kvm_vcpu *vcpu)
{
struct rtas_token_definition *d;
struct rtas_args args;
rtas_arg_t *orig_rets;
gpa_t args_phys;
int rc;
/* r4 contains the guest physical address of the RTAS args */
args_phys = kvmppc_get_gpr(vcpu, 4);
rc = kvm_read_guest(vcpu->kvm, args_phys, &args, sizeof(args));
if (rc)
goto fail;
/*
* args->rets is a pointer into args->args. Now that we've
* copied args we need to fix it up to point into our copy,
* not the guest args. We also need to save the original
* value so we can restore it on the way out.
*/
orig_rets = args.rets;
args.rets = &args.args[args.nargs];
mutex_lock(&vcpu->kvm->lock);
rc = -ENOENT;
list_for_each_entry(d, &vcpu->kvm->arch.rtas_tokens, list) {
if (d->token == args.token) {
d->handler->handler(vcpu, &args);
rc = 0;
break;
}
}
mutex_unlock(&vcpu->kvm->lock);
if (rc == 0) {
args.rets = orig_rets;
rc = kvm_write_guest(vcpu->kvm, args_phys, &args, sizeof(args));
if (rc)
goto fail;
}
return rc;
fail:
/*
* We only get here if the guest has called RTAS with a bogus
* args pointer. That means we can't get to the args, and so we
* can't fail the RTAS call. So fail right out to userspace,
* which should kill the guest.
*/
return rc;
}
void kvmppc_rtas_tokens_free(struct kvm *kvm)
{
struct rtas_token_definition *d, *tmp;
lockdep_assert_held(&kvm->lock);
list_for_each_entry_safe(d, tmp, &kvm->arch.rtas_tokens, list) {
list_del(&d->list);
kfree(d);
}
}
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