1 files changed, 307 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/book3s_rtas.c b/arch/powerpc/kvm/book3s_rtas.c
new file mode 100644
index 000000000..0f847f1e5
--- /dev/null
+++ b/arch/powerpc/kvm/book3s_rtas.c
@@ -0,0 +1,307 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2012 Michael Ellerman, IBM Corporation.
+ */
+
+#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;
+
+	vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+	rc = kvm_read_guest(vcpu->kvm, args_phys, &args, sizeof(args));
+	srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+	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;
+	if (be32_to_cpu(args.nargs) >= ARRAY_SIZE(args.args)) {
+		/*
+		 * Don't overflow our args array: ensure there is room for
+		 * at least rets[0] (even if the call specifies 0 nret).
+		 *
+		 * Each handler must then check for the correct nargs and nret
+		 * values, but they may always return failure in rets[0].
+		 */
+		rc = -EINVAL;
+		goto fail;
+	}
+	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 or nargs/nret values that would overflow the
+	 * array. 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.
+	 *
+	 * SLOF should actually pass the hcall return value from the
+	 * rtas handler call in r3, so enter_rtas could be modified to
+	 * return a failure indication in r3 and we could return such
+	 * errors to the guest rather than failing to host userspace.
+	 * However old guests that don't test for failure could then
+	 * continue silently after errors, so for now we won't do this.
+	 */
+	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);
+	}
+}