bhyve: add basic qemu fwcfg implementation

qemu's fwcfg and bhyve's fwctl are both used to configure ovmf. qemu's
fwcfg is much more powerfull than bhyve's fwctl. For that reason, add
support for qemu's fwcfg.

Reviewed by:		markj
MFC after:		1 week
Sponsored by:		Beckhoff Automation GmbH & Co. KG
Differential Revision:	https://reviews.freebsd.org/D38331

(cherry picked from commit 9b99de77f16029dd55326e0210072b14ec1ad960)

2 files changed, 126 insertions, 0 deletions

diff --git a/usr.sbin/bhyve/qemu_fwcfg.c b/usr.sbin/bhyve/qemu_fwcfg.c
new file mode 100644
index 000000000000..5d3070abf285
--- /dev/null
+++ b/usr.sbin/bhyve/qemu_fwcfg.c
@@ -0,0 +1,114 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2021 Beckhoff Automation GmbH & Co. KG
+ * Author: Corvin Köhne <c.koehne@beckhoff.com>
+ */
+
+#include <sys/param.h>
+
+#include <machine/vmm.h>
+
+#include <err.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "acpi_device.h"
+#include "inout.h"
+#include "qemu_fwcfg.h"
+
+#define QEMU_FWCFG_ACPI_DEVICE_NAME "FWCF"
+#define QEMU_FWCFG_ACPI_HARDWARE_ID "QEMU0002"
+
+#define QEMU_FWCFG_SELECTOR_PORT_NUMBER 0x510
+#define QEMU_FWCFG_SELECTOR_PORT_SIZE 1
+#define QEMU_FWCFG_SELECTOR_PORT_FLAGS IOPORT_F_INOUT
+#define QEMU_FWCFG_DATA_PORT_NUMBER 0x511
+#define QEMU_FWCFG_DATA_PORT_SIZE 1
+#define QEMU_FWCFG_DATA_PORT_FLAGS \
+	IOPORT_F_INOUT /* QEMU v2.4+ ignores writes */
+
+struct qemu_fwcfg_softc {
+	struct acpi_device *acpi_dev;
+};
+
+static struct qemu_fwcfg_softc fwcfg_sc;
+
+static int
+qemu_fwcfg_selector_port_handler(struct vmctx *const ctx __unused, const int in,
+    const int port __unused, const int bytes, uint32_t *const eax,
+    void *const arg __unused)
+{
+	return (0);
+}
+
+static int
+qemu_fwcfg_data_port_handler(struct vmctx *const ctx __unused, const int in,
+    const int port __unused, const int bytes, uint32_t *const eax,
+    void *const arg __unused)
+{
+	return (0);
+}
+
+static int
+qemu_fwcfg_register_port(const char *const name, const int port, const int size,
+    const int flags, const inout_func_t handler)
+{
+	struct inout_port iop;
+
+	bzero(&iop, sizeof(iop));
+	iop.name = name;
+	iop.port = port;
+	iop.size = size;
+	iop.flags = flags;
+	iop.handler = handler;
+
+	return (register_inout(&iop));
+}
+
+int
+qemu_fwcfg_init(struct vmctx *const ctx)
+{
+	int error;
+
+	error = acpi_device_create(&fwcfg_sc.acpi_dev, ctx,
+	    QEMU_FWCFG_ACPI_DEVICE_NAME, QEMU_FWCFG_ACPI_HARDWARE_ID);
+	if (error) {
+		warnx("%s: failed to create ACPI device for QEMU FwCfg",
+		    __func__);
+		goto done;
+	}
+
+	error = acpi_device_add_res_fixed_ioport(fwcfg_sc.acpi_dev,
+	    QEMU_FWCFG_SELECTOR_PORT_NUMBER, 2);
+	if (error) {
+		warnx("%s: failed to add fixed IO port for QEMU FwCfg",
+		    __func__);
+		goto done;
+	}
+
+	/* add handlers for fwcfg ports */
+	if ((error = qemu_fwcfg_register_port("qemu_fwcfg_selector",
+	    QEMU_FWCFG_SELECTOR_PORT_NUMBER, QEMU_FWCFG_SELECTOR_PORT_SIZE,
+	    QEMU_FWCFG_SELECTOR_PORT_FLAGS,
+	    qemu_fwcfg_selector_port_handler)) != 0) {
+		warnx("%s: Unable to register qemu fwcfg selector port 0x%x",
+		    __func__, QEMU_FWCFG_SELECTOR_PORT_NUMBER);
+		goto done;
+	}
+	if ((error = qemu_fwcfg_register_port("qemu_fwcfg_data",
+	    QEMU_FWCFG_DATA_PORT_NUMBER, QEMU_FWCFG_DATA_PORT_SIZE,
+	    QEMU_FWCFG_DATA_PORT_FLAGS, qemu_fwcfg_data_port_handler)) != 0) {
+		warnx("%s: Unable to register qemu fwcfg data port 0x%x",
+		    __func__, QEMU_FWCFG_DATA_PORT_NUMBER);
+		goto done;
+	}
+
+done:
+	if (error) {
+		acpi_device_destroy(fwcfg_sc.acpi_dev);
+	}
+
+	return (error);
+}
diff --git a/usr.sbin/bhyve/qemu_fwcfg.h b/usr.sbin/bhyve/qemu_fwcfg.h
new file mode 100644
index 000000000000..26c4db0ff71e
--- /dev/null
+++ b/usr.sbin/bhyve/qemu_fwcfg.h
@@ -0,0 +1,12 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2021 Beckhoff Automation GmbH & Co. KG
+ * Author: Corvin Köhne <c.koehne@beckhoff.com>
+ */
+
+#pragma once
+
+#include <vmmapi.h>
+
+int qemu_fwcfg_init(struct vmctx *const ctx);