bhyve: allow device specific DSDT entries

This feature will be used by future commits to implement a device
specific method (_DSM) for TPM devices.

Reviewed by:		markj
MFC after:		1 week
Sponsored by:		Beckhoff Automation GmbH & Co. KG
Differential Revision:	https://reviews.freebsd.org/D39321

usr.sbin/bhyve/acpi_device.c

@@ -190,6 +190,11 @@ acpi_device_write_dsdt(const struct acpi_device *const dev)
 	BASL_EXEC(acpi_device_write_dsdt_crs(dev));
 	dsdt_unindent(4);
 	dsdt_line("      })");
+	if (dev->emul->write_dsdt != NULL) {
+		dsdt_indent(3);
+		BASL_EXEC(dev->emul->write_dsdt(dev));
+		dsdt_unindent(3);
+	}
 	dsdt_line("    }");
 	dsdt_line("  }");
 

usr.sbin/bhyve/acpi_device.h

@@ -23,12 +23,15 @@ struct acpi_device;
  * @param hid         Used as _HID in the DSDT.
  * @param build_table Called to build a device specific ACPI table like the TPM2
  *                    table.
+ * @param write_dsdt  Called to append the DSDT with device specific
+ *                    information.
  */
 struct acpi_device_emul {
 	const char *name;
 	const char *hid;
 
 	int (*build_table)(const struct acpi_device *dev);
+	int (*write_dsdt)(const struct acpi_device *dev);
 };
 
 /**