KVM: selftests: Add support for vcpu_args_set to aarch64 and s390x

Currently vcpu_args_set is only implemented for x86. This makes writing
tests with multiple vCPUs difficult as each guest vCPU must either a.)
do the same thing or b.) derive some kind of unique token from it's
registers or the architecture. To simplify the process of writing tests
with multiple vCPUs for s390 and aarch64, add set args functions for
those architectures.
Signed-off-by: Ben Gardon <bgardon@google.com>
[Fixed array index (num => i) and made some style changes.]
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/lib/aarch64/processor.c

@@ -333,3 +333,38 @@ void vm_vcpu_add_default(struct kvm_vm *vm, uint32_t vcpuid, void *guest_code)
 {
 	aarch64_vcpu_add_default(vm, vcpuid, NULL, guest_code);
 }
+
+
+/* VM VCPU Args Set
+ *
+ * Input Args:
+ *   vm - Virtual Machine
+ *   vcpuid - VCPU ID
+ *   num - number of arguments
+ *   ... - arguments, each of type uint64_t
+ *
+ * Output Args: None
+ *
+ * Return: None
+ *
+ * Sets the first num function input arguments to the values
+ * given as variable args.  Each of the variable args is expected to
+ * be of type uint64_t. The registers set by this function are r0-r7.
+ */
+void vcpu_args_set(struct kvm_vm *vm, uint32_t vcpuid, unsigned int num, ...)
+{
+	va_list ap;
+	int i;
+
+	TEST_ASSERT(num >= 1 && num <= 8, "Unsupported number of args,\n"
+		    "  num: %u\n", num);
+
+	va_start(ap, num);
+
+	for (i = 0; i < num; i++) {
+		set_reg(vm, vcpuid, ARM64_CORE_REG(regs.regs[i]),
+			va_arg(ap, uint64_t));
+	}
+
+	va_end(ap);
+}

tools/testing/selftests/kvm/lib/s390x/processor.c

@@ -269,6 +269,42 @@ void vm_vcpu_add_default(struct kvm_vm *vm, uint32_t vcpuid, void *guest_code)
 	run->psw_addr = (uintptr_t)guest_code;
 }
 
+/* VM VCPU Args Set
+ *
+ * Input Args:
+ *   vm - Virtual Machine
+ *   vcpuid - VCPU ID
+ *   num - number of arguments
+ *   ... - arguments, each of type uint64_t
+ *
+ * Output Args: None
+ *
+ * Return: None
+ *
+ * Sets the first num function input arguments to the values
+ * given as variable args.  Each of the variable args is expected to
+ * be of type uint64_t. The registers set by this function are r2-r6.
+ */
+void vcpu_args_set(struct kvm_vm *vm, uint32_t vcpuid, unsigned int num, ...)
+{
+	va_list ap;
+	struct kvm_regs regs;
+	int i;
+
+	TEST_ASSERT(num >= 1 && num <= 5, "Unsupported number of args,\n"
+		    "  num: %u\n",
+		    num);
+
+	va_start(ap, num);
+	vcpu_regs_get(vm, vcpuid, &regs);
+
+	for (i = 0; i < num; i++)
+		regs.gprs[i + 2] = va_arg(ap, uint64_t);
+
+	vcpu_regs_set(vm, vcpuid, &regs);
+	va_end(ap);
+}
+
 void vcpu_dump(FILE *stream, struct kvm_vm *vm, uint32_t vcpuid, uint8_t indent)
 {
 	struct vcpu *vcpu = vm->vcpu_head;