arch/powerpc/kvm/book3s_rtas.c

   1 /*
   2  * Copyright 2012 Michael Ellerman, IBM Corporation.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2, as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/kvm_host.h>
  11 #include <linux/kvm.h>
  12 #include <linux/err.h>
  13
  14 #include <linux/uaccess.h>
  15 #include <asm/kvm_book3s.h>
  16 #include <asm/kvm_ppc.h>
  17 #include <asm/hvcall.h>
  18 #include <asm/rtas.h>
  19 #include <asm/xive.h>
  20
  21 #ifdef CONFIG_KVM_XICS
  22 static void kvm_rtas_set_xive(struct kvm_vcpu *vcpu, struct rtas_args *args)
  23 {
  24         u32 irq, server, priority;
  25         int rc;
  26
  27         if (be32_to_cpu(args->nargs) != 3 || be32_to_cpu(args->nret) != 1) {
  28                 rc = -3;
  29                 goto out;
  30         }
  31
  32         irq = be32_to_cpu(args->args[0]);
  33         server = be32_to_cpu(args->args[1]);
  34         priority = be32_to_cpu(args->args[2]);
  35
  36         if (xive_enabled())
  37                 rc = kvmppc_xive_set_xive(vcpu->kvm, irq, server, priority);
  38         else
  39                 rc = kvmppc_xics_set_xive(vcpu->kvm, irq, server, priority);
  40         if (rc)
  41                 rc = -3;
  42 out:
  43         args->rets[0] = cpu_to_be32(rc);
  44 }
  45
  46 static void kvm_rtas_get_xive(struct kvm_vcpu *vcpu, struct rtas_args *args)
  47 {
  48         u32 irq, server, priority;
  49         int rc;
  50
  51         if (be32_to_cpu(args->nargs) != 1 || be32_to_cpu(args->nret) != 3) {
  52                 rc = -3;
  53                 goto out;
  54         }
  55
  56         irq = be32_to_cpu(args->args[0]);
  57
  58         server = priority = 0;
  59         if (xive_enabled())
  60                 rc = kvmppc_xive_get_xive(vcpu->kvm, irq, &server, &priority);
  61         else
  62                 rc = kvmppc_xics_get_xive(vcpu->kvm, irq, &server, &priority);
  63         if (rc) {
  64                 rc = -3;
  65                 goto out;
  66         }
  67
  68         args->rets[1] = cpu_to_be32(server);
  69         args->rets[2] = cpu_to_be32(priority);
  70 out:
  71         args->rets[0] = cpu_to_be32(rc);
  72 }
  73
  74 static void kvm_rtas_int_off(struct kvm_vcpu *vcpu, struct rtas_args *args)
  75 {
  76         u32 irq;
  77         int rc;
  78
  79         if (be32_to_cpu(args->nargs) != 1 || be32_to_cpu(args->nret) != 1) {
  80                 rc = -3;
  81                 goto out;
  82         }
  83
  84         irq = be32_to_cpu(args->args[0]);
  85
  86         if (xive_enabled())
  87                 rc = kvmppc_xive_int_off(vcpu->kvm, irq);
  88         else
  89                 rc = kvmppc_xics_int_off(vcpu->kvm, irq);
  90         if (rc)
  91                 rc = -3;
  92 out:
  93         args->rets[0] = cpu_to_be32(rc);
  94 }
  95
  96 static void kvm_rtas_int_on(struct kvm_vcpu *vcpu, struct rtas_args *args)
  97 {
  98         u32 irq;
  99         int rc;
 100
 101         if (be32_to_cpu(args->nargs) != 1 || be32_to_cpu(args->nret) != 1) {
 102                 rc = -3;
 103                 goto out;
 104         }
 105
 106         irq = be32_to_cpu(args->args[0]);
 107
 108         if (xive_enabled())
 109                 rc = kvmppc_xive_int_on(vcpu->kvm, irq);
 110         else
 111                 rc = kvmppc_xics_int_on(vcpu->kvm, irq);
 112         if (rc)
 113                 rc = -3;
 114 out:
 115         args->rets[0] = cpu_to_be32(rc);
 116 }
 117 #endif /* CONFIG_KVM_XICS */
 118
 119 struct rtas_handler {
 120         void (*handler)(struct kvm_vcpu *vcpu, struct rtas_args *args);
 121         char *name;
 122 };
 123
 124 static struct rtas_handler rtas_handlers[] = {
 125 #ifdef CONFIG_KVM_XICS
 126         { .name = "ibm,set-xive", .handler = kvm_rtas_set_xive },
 127         { .name = "ibm,get-xive", .handler = kvm_rtas_get_xive },
 128         { .name = "ibm,int-off",  .handler = kvm_rtas_int_off },
 129         { .name = "ibm,int-on",   .handler = kvm_rtas_int_on },
 130 #endif
 131 };
 132
 133 struct rtas_token_definition {
 134         struct list_head list;
 135         struct rtas_handler *handler;
 136         u64 token;
 137 };
 138
 139 static int rtas_name_matches(char *s1, char *s2)
 140 {
 141         struct kvm_rtas_token_args args;
 142         return !strncmp(s1, s2, sizeof(args.name));
 143 }
 144
 145 static int rtas_token_undefine(struct kvm *kvm, char *name)
 146 {
 147         struct rtas_token_definition *d, *tmp;
 148
 149         lockdep_assert_held(&kvm->lock);
 150
 151         list_for_each_entry_safe(d, tmp, &kvm->arch.rtas_tokens, list) {
 152                 if (rtas_name_matches(d->handler->name, name)) {
 153                         list_del(&d->list);
 154                         kfree(d);
 155                         return 0;
 156                 }
 157         }
 158
 159         /* It's not an error to undefine an undefined token */
 160         return 0;
 161 }
 162
 163 static int rtas_token_define(struct kvm *kvm, char *name, u64 token)
 164 {
 165         struct rtas_token_definition *d;
 166         struct rtas_handler *h = NULL;
 167         bool found;
 168         int i;
 169
 170         lockdep_assert_held(&kvm->lock);
 171
 172         list_for_each_entry(d, &kvm->arch.rtas_tokens, list) {
 173                 if (d->token == token)
 174                         return -EEXIST;
 175         }
 176
 177         found = false;
 178         for (i = 0; i < ARRAY_SIZE(rtas_handlers); i++) {
 179                 h = &rtas_handlers[i];
 180                 if (rtas_name_matches(h->name, name)) {
 181                         found = true;
 182                         break;
 183                 }
 184         }
 185
 186         if (!found)
 187                 return -ENOENT;
 188
 189         d = kzalloc(sizeof(*d), GFP_KERNEL);
 190         if (!d)
 191                 return -ENOMEM;
 192
 193         d->handler = h;
 194         d->token = token;
 195
 196         list_add_tail(&d->list, &kvm->arch.rtas_tokens);
 197
 198         return 0;
 199 }
 200
 201 int kvm_vm_ioctl_rtas_define_token(struct kvm *kvm, void __user *argp)
 202 {
 203         struct kvm_rtas_token_args args;
 204         int rc;
 205
 206         if (copy_from_user(&args, argp, sizeof(args)))
 207                 return -EFAULT;
 208
 209         mutex_lock(&kvm->lock);
 210
 211         if (args.token)
 212                 rc = rtas_token_define(kvm, args.name, args.token);
 213         else
 214                 rc = rtas_token_undefine(kvm, args.name);
 215
 216         mutex_unlock(&kvm->lock);
 217
 218         return rc;
 219 }
 220
 221 int kvmppc_rtas_hcall(struct kvm_vcpu *vcpu)
 222 {
 223         struct rtas_token_definition *d;
 224         struct rtas_args args;
 225         rtas_arg_t *orig_rets;
 226         gpa_t args_phys;
 227         int rc;
 228
 229         /*
 230          * r4 contains the guest physical address of the RTAS args
 231          * Mask off the top 4 bits since this is a guest real address
 232          */
 233         args_phys = kvmppc_get_gpr(vcpu, 4) & KVM_PAM;
 234
 235         rc = kvm_read_guest(vcpu->kvm, args_phys, &args, sizeof(args));
 236         if (rc)
 237                 goto fail;
 238
 239         /*
 240          * args->rets is a pointer into args->args. Now that we've
 241          * copied args we need to fix it up to point into our copy,
 242          * not the guest args. We also need to save the original
 243          * value so we can restore it on the way out.
 244          */
 245         orig_rets = args.rets;
 246         args.rets = &args.args[be32_to_cpu(args.nargs)];
 247
 248         mutex_lock(&vcpu->kvm->lock);
 249
 250         rc = -ENOENT;
 251         list_for_each_entry(d, &vcpu->kvm->arch.rtas_tokens, list) {
 252                 if (d->token == be32_to_cpu(args.token)) {
 253                         d->handler->handler(vcpu, &args);
 254                         rc = 0;
 255                         break;
 256                 }
 257         }
 258
 259         mutex_unlock(&vcpu->kvm->lock);
 260
 261         if (rc == 0) {
 262                 args.rets = orig_rets;
 263                 rc = kvm_write_guest(vcpu->kvm, args_phys, &args, sizeof(args));
 264                 if (rc)
 265                         goto fail;
 266         }
 267
 268         return rc;
 269
 270 fail:
 271         /*
 272          * We only get here if the guest has called RTAS with a bogus
 273          * args pointer. That means we can't get to the args, and so we
 274          * can't fail the RTAS call. So fail right out to userspace,
 275          * which should kill the guest.
 276          */
 277         return rc;
 278 }
 279 EXPORT_SYMBOL_GPL(kvmppc_rtas_hcall);
 280
 281 void kvmppc_rtas_tokens_free(struct kvm *kvm)
 282 {
 283         struct rtas_token_definition *d, *tmp;
 284
 285         lockdep_assert_held(&kvm->lock);
 286
 287         list_for_each_entry_safe(d, tmp, &kvm->arch.rtas_tokens, list) {
 288                 list_del(&d->list);
 289                 kfree(d);
 290         }
 291 }