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