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-rw-r--r--arch/powerpc/kvm/book3s_rtas.c307
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);
+ }
+}