1 files changed, 182 insertions, 0 deletions

diff --git a/arch/powerpc/kvm/book3s_rtas.c b/arch/powerpc/kvm/book3s_rtas.c
new file mode 100644
index 000000000000..6ad7050eb67d
--- /dev/null
+++ b/arch/powerpc/kvm/book3s_rtas.c
@@ -0,0 +1,182 @@
+/*
+ * 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);
+        }
+}