text: /*
   * 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 <linux/uaccess.h>
  #include <asm/kvm_book3s.h>
  #include <asm/kvm_ppc.h>
  #include <asm/hvcall.h>
  #include <asm/rtas.h>
  #include <asm/xive.h>
  
  #ifdef CONFIG_KVM_XICS
  static void kvm_rtas_set_xive(struct kvm_vcpu *vcpu, struct rtas_args *args)
  {
  	u32 irq, server, priority;
  	int rc;
  
  	if (be32_to_cpu(args->nargs) != 3 || be32_to_cpu(args->nret) != 1) {
  		rc = -3;
  		goto out;
  	}
  
  	irq = be32_to_cpu(args->args[0]);
  	server = be32_to_cpu(args->args[1]);
  	priority = be32_to_cpu(args->args[2]);
  
  	if (xics_on_xive())
  		rc = kvmppc_xive_set_xive(vcpu->kvm, irq, server, priority);
  	else
  		rc = kvmppc_xics_set_xive(vcpu->kvm, irq, server, priority);
  	if (rc)
  		rc = -3;
  out:
  	args->rets[0] = cpu_to_be32(rc);
  }
  
  static void kvm_rtas_get_xive(struct kvm_vcpu *vcpu, struct rtas_args *args)
  {
  	u32 irq, server, priority;
  	int rc;
  
  	if (be32_to_cpu(args->nargs) != 1 || be32_to_cpu(args->nret) != 3) {
  		rc = -3;
  		goto out;
  	}
  
  	irq = be32_to_cpu(args->args[0]);
  
  	server = priority = 0;
  	if (xics_on_xive())
  		rc = kvmppc_xive_get_xive(vcpu->kvm, irq, &server, &priority);
  	else
  		rc = kvmppc_xics_get_xive(vcpu->kvm, irq, &server, &priority);
  	if (rc) {
  		rc = -3;
  		goto out;
  	}
  
  	args->rets[1] = cpu_to_be32(server);
  	args->rets[2] = cpu_to_be32(priority);
  out:
  	args->rets[0] = cpu_to_be32(rc);
  }
  
  static void kvm_rtas_int_off(struct kvm_vcpu *vcpu, struct rtas_args *args)
  {
  	u32 irq;
  	int rc;
  
  	if (be32_to_cpu(args->nargs) != 1 || be32_to_cpu(args->nret) != 1) {
  		rc = -3;
  		goto out;
  	}
  
  	irq = be32_to_cpu(args->args[0]);
  
  	if (xics_on_xive())
  		rc = kvmppc_xive_int_off(vcpu->kvm, irq);
  	else
  		rc = kvmppc_xics_int_off(vcpu->kvm, irq);
  	if (rc)
  		rc = -3;
  out:
  	args->rets[0] = cpu_to_be32(rc);
  }
  
  static void kvm_rtas_int_on(struct kvm_vcpu *vcpu, struct rtas_args *args)
  {
  	u32 irq;
  	int rc;
  
  	if (be32_to_cpu(args->nargs) != 1 || be32_to_cpu(args->nret) != 1) {
  		rc = -3;
  		goto out;
  	}
  
  	irq = be32_to_cpu(args->args[0]);
  
  	if (xics_on_xive())
  		rc = kvmppc_xive_int_on(vcpu->kvm, irq);
  	else
  		rc = kvmppc_xics_int_on(vcpu->kvm, irq);
  	if (rc)
  		rc = -3;
  out:
  	args->rets[0] = cpu_to_be32(rc);
  }
  #endif /* CONFIG_KVM_XICS */
  
  struct rtas_handler {
  	void (*handler)(struct kvm_vcpu *vcpu, struct rtas_args *args);
  	char *name;
  };
  
  static struct rtas_handler rtas_handlers[] = {
  #ifdef CONFIG_KVM_XICS
  	{ .name = "ibm,set-xive", .handler = kvm_rtas_set_xive },
  	{ .name = "ibm,get-xive", .handler = kvm_rtas_get_xive },
  	{ .name = "ibm,int-off",  .handler = kvm_rtas_int_off },
  	{ .name = "ibm,int-on",   .handler = kvm_rtas_int_on },
  #endif
  };
  
  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->arch.rtas_token_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->arch.rtas_token_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->arch.rtas_token_lock);
  
  	if (args.token)
  		rc = rtas_token_define(kvm, args.name, args.token);
  	else
  		rc = rtas_token_undefine(kvm, args.name);
  
  	mutex_unlock(&kvm->arch.rtas_token_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
  	 * Mask off the top 4 bits since this is a guest real address
  	 */
  	args_phys = kvmppc_get_gpr(vcpu, 4) & KVM_PAM;
  
  	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[be32_to_cpu(args.nargs)];
  
  	mutex_lock(&vcpu->kvm->arch.rtas_token_lock);
  
  	rc = -ENOENT;
  	list_for_each_entry(d, &vcpu->kvm->arch.rtas_tokens, list) {
  		if (d->token == be32_to_cpu(args.token)) {
  			d->handler->handler(vcpu, &args);
  			rc = 0;
  			break;
  		}
  	}
  
  	mutex_unlock(&vcpu->kvm->arch.rtas_token_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;
  }
  EXPORT_SYMBOL_GPL(kvmppc_rtas_hcall);
  
  void kvmppc_rtas_tokens_free(struct kvm *kvm)
  {
  	struct rtas_token_definition *d, *tmp;
  
  	list_for_each_entry_safe(d, tmp, &kvm->arch.rtas_tokens, list) {
  		list_del(&d->list);
  		kfree(d);
  	}
  }
  