bhyve: add basic TPM device

Add an empty TPM device struct which will be used for TPM emulation in
subsequent commits.

Reviewed by:		markj
MFC after:		1 week
Sponsored by:		Beckhoff Automation GmbH & Co. KG
Differential Revision:	https://reviews.freebsd.org/D40452

usr.sbin/bhyve/Makefile

@@ -72,6 +72,7 @@ SRCS=	\
 	smbiostbl.c		\
 	sockstream.c		\
 	task_switch.c		\
+	tpm_device.c		\
 	uart_emul.c		\
 	usb_emul.c		\
 	usb_mouse.c		\

usr.sbin/bhyve/tpm_device.c

@@ -0,0 +1,68 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023 Beckhoff Automation GmbH & Co. KG
+ * Author: Corvin Köhne <corvink@FreeBSD.org>
+ */
+
+#include <sys/types.h>
+
+#include <err.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <vmmapi.h>
+
+#include "config.h"
+#include "tpm_device.h"
+
+struct tpm_device {
+	struct vmctx *vm_ctx;
+};
+
+void
+tpm_device_destroy(struct tpm_device *const dev)
+{
+	if (dev == NULL)
+		return;
+
+	free(dev);
+}
+
+int
+tpm_device_create(struct tpm_device **const new_dev, struct vmctx *const vm_ctx,
+    nvlist_t *const nvl)
+{
+	struct tpm_device *dev = NULL;
+	const char *value;
+	int error;
+
+	if (new_dev == NULL || vm_ctx == NULL) {
+		error = EINVAL;
+		goto err_out;
+	}
+
+	value = get_config_value_node(nvl, "version");
+	if (value == NULL || strcmp(value, "2.0")) {
+		warnx("%s: unsupported tpm version %s", __func__, value);
+		error = EINVAL;
+		goto err_out;
+	}
+
+	dev = calloc(1, sizeof(*dev));
+	if (dev == NULL) {
+		error = ENOMEM;
+		goto err_out;
+	}
+
+	dev->vm_ctx = vm_ctx;
+
+	*new_dev = dev;
+
+	return (0);
+
+err_out:
+	tpm_device_destroy(dev);
+
+	return (error);
+}

usr.sbin/bhyve/tpm_device.h

@@ -0,0 +1,18 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023 Beckhoff Automation GmbH & Co. KG
+ * Author: Corvin Köhne <corvink@FreeBSD.org>
+ */
+
+#pragma once
+
+#include <vmmapi.h>
+
+#include "config.h"
+
+struct tpm_device;
+
+int tpm_device_create(struct tpm_device **new_dev, struct vmctx *vm_ctx,
+    nvlist_t *nvl);
+void tpm_device_destroy(struct tpm_device *dev);