1 files changed, 209 insertions, 0 deletions

diff --git a/classes/qemuboot-xen-dtb.bbclass b/classes/qemuboot-xen-dtb.bbclass
new file mode 100644
index 00000000..08f9b02e
--- /dev/null
+++ b/classes/qemuboot-xen-dtb.bbclass
@@ -0,0 +1,209 @@
+# Enable booting Xen with qemuboot / runqemu: generate device tree
+#
+# Copyright (c) 2021 Star Lab Corp. All rights reserved.
+#
+# Author: Christopher Clark <christopher.clark@starlab.io>
+
+# Interface variables:
+#
+# QB_DTB : defined in qemuboot.bbclass.
+# If set, this class will generate the specified device tree file.
+#
+# QB_XEN_CMDLINE_EXTRA :
+# A string to be appended to the default Xen hypervisor boot command line,
+# for supplying Xen boot options.
+# The device tree that this bbclass generates will contain Xen command
+# line options to connect the Xen console to the Qemu serial port.
+#
+# QB_XEN_DOMAIN_MODULES :
+# A space-separated list of colon-separated entries:
+#   "<file for the module>:<load memory address>:<module compatibility string>"
+#
+# QB_XEN_DOM0_BOOTARGS :
+# A string for specifying Dom0 boot options for the Xen section of the device
+# tree.
+#
+# QB_XEN_DTB_TASK_DEPENDS :
+# The task dependencies for the DTB generation. A default is provided.
+#
+# See also: Other QB_ variables as defined by the qemuboot.bbclass.
+
+write_lops_xen_section() {
+    cat <<EOF >"$1"
+/dts-v1/;
+/ {
+    compatible = "system-device-tree-v1";
+    lops {
+        /* Connect the Xen console to Qemu dtuart */
+        lop_1 {
+            compatible = "system-device-tree-v1,lop,code-v1";
+            code = "
+                chosen = node.tree['/chosen']
+                stdout_path = str(chosen['stdout-path'].value[0])
+                chosen['xen,xen-bootargs'] = \
+                        'console=dtuart dtuart=%s' % stdout_path
+                return True
+            ";
+        };
+        lop_2 {
+            compatible = "system-device-tree-v1,lop,modify";
+            modify = "/chosen:xen,dom0-bootargs:${QB_XEN_DOM0_BOOTARGS}";
+        };
+        lop_3 {
+            compatible = "system-device-tree-v1,lop,modify";
+            modify = "/chosen:#address-cells:<1>";
+        };
+        lop_4 {
+            compatible = "system-device-tree-v1,lop,modify";
+            modify = "/chosen:#size-cells:<1>";
+        };
+     };
+};
+EOF
+}
+
+write_lop_add_to_xen_cmdline() {
+    EXTRA_XEN_BOOTARGS="$2"
+    cat <<EOF >"$1"
+/dts-v1/;
+/ {
+    compatible = "system-device-tree-v1";
+    lops {
+        lop_1 {
+            compatible = "system-device-tree-v1,lop,code-v1";
+            options = "extra_xen_bootargs:${EXTRA_XEN_BOOTARGS}";
+            code = "
+                chosen = node.tree['/chosen']
+                xen_bootargs = str(chosen['xen,xen-bootargs'].value)
+                chosen['xen,xen-bootargs'] = '%s %s' % \
+                     (xen_bootargs, extra_xen_bootargs)
+                return True
+            ";
+        };
+     };
+};
+EOF
+}
+
+write_lop_add_chosen_module() {
+    ADDR="$2"
+    SIZE="$3"
+    MODULE_TYPE="$4"
+    cat <<EOF >"$1"
+/dts-v1/;
+/ {
+    compatible = "system-device-tree-v1";
+    lops {
+        lop_1 {
+            compatible = "system-device-tree-v1,lop,add";
+            node_src = "module@${ADDR}";
+            node_dest = "/chosen/module@${ADDR}";
+
+            module@${ADDR} {
+                compatible = "multiboot,module", "${MODULE_TYPE}";
+                reg = <${ADDR} ${SIZE}>;
+            };
+        };
+     };
+};
+EOF
+}
+
+generate_xen_qemuboot_dtb() {
+    # First: invoke qemu to generate an initial device tree.
+    # Parameters supplied here inspired by inspection of:
+    #   runqemu "${IMAGE_BASENAME}" nographic slirp \
+    #            qemuparams='-dtb "" -machine dumpdtb=${B}/qemu-dumped.dtb'
+    ${QB_SYSTEM_NAME} \
+        -device qemu-xhci \
+        -device usb-tablet \
+        -device usb-kbd \
+        -machine virt,gic-version=3 \
+        -machine virtualization=true \
+        ${QB_CPU} \
+        ${QB_SMP} \
+        ${QB_MEM} \
+        -nographic \
+        -serial mon:stdio \
+        -machine "dumpdtb=${B}/qemu-dumped.dtb"
+
+    # Lopper generates temporary files in cwd, so run it within ${B}
+    cd "${B}"
+    write_lops_xen_section "${B}/lop-insert-xen-section.dts"
+
+    write_lop_add_to_xen_cmdline "${B}/lop-xen-cmdline.dts" \
+        "${QB_XEN_CMDLINE_EXTRA}"
+
+    if [ -z "${QB_XEN_DOMAIN_MODULES}" ]; then
+        bbwarn "No domain modules: please set QB_XEN_DOMAIN_MODULES"
+    fi
+
+    for DOMAIN_MODULE in ${QB_XEN_DOMAIN_MODULES}
+    do
+        MODULE_FILE="$(echo ${DOMAIN_MODULE} | cut -f1 -d:)"
+        ADDR="$(echo ${DOMAIN_MODULE} | cut -f2 -d:)"
+        MODULE_TYPE="$(echo ${DOMAIN_MODULE} | cut -f3 -d:)"
+        RESOLVED_FILE="$(readlink -f ${MODULE_FILE})"
+        SIZE=$(printf '0x%x\n' $(stat -c '%s' "${RESOLVED_FILE}"))
+        [ "x${SIZE}" != "x0x0" ] || bbfatal No module: "${MODULE_FILE}"
+        write_lop_add_chosen_module "${B}/lop-add-module-${ADDR}.dts" \
+            "${ADDR}" "${SIZE}" "${MODULE_TYPE}"
+        LOP_MODULE_ARGS="${LOP_MODULE_ARGS} -i ${B}/lop-add-module-${ADDR}.dts"
+    done
+
+    QEMUBOOT_DTB="${IMGDEPLOYDIR}/${QB_DTB}"
+    QEMUBOOT_DTB_LINK="${IMGDEPLOYDIR}/${QB_DTB_LINK}"
+
+    lopper.py --werror --verbose \
+        -i "${B}/lop-insert-xen-section.dts" \
+        -i "${B}/lop-xen-cmdline.dts" \
+        ${LOP_MODULE_ARGS} \
+        -f -o "${QEMUBOOT_DTB}" \
+            "${B}/qemu-dumped.dtb"
+
+    # To assist debugging:
+    dtc -I dtb -O dts -o "${B}/output.dts" "${QEMUBOOT_DTB}"
+
+    if [ "${QEMUBOOT_DTB_LINK}" != "${QEMUBOOT_DTB}" ] ; then
+        if [ -e "${QEMUBOOT_DTB_LINK}" ] ; then
+            rm "${QEMUBOOT_DTB_LINK}"
+        fi
+        ln -s "${QB_DTB}" "${QEMUBOOT_DTB_LINK}"
+    fi
+}
+
+do_write_xen_qemuboot_dtb() {
+    # Not all architectures qemuboot with a device tree binary, so check
+    # to see if one is needed. This allows this bbclass file to be used
+    # in the same image recipe for multiple architectures.
+    if [ -n "${QB_DTB}" ] ; then
+        generate_xen_qemuboot_dtb
+    fi
+}
+
+addtask do_write_xen_qemuboot_dtb after do_write_qemuboot_conf before do_image
+# Task dependency:
+# An expected common case is that the kernel for at least one of the initial
+# domains (eg. dom0) is deployed from the virtual/kernel recipe, so
+# add virtual/kernel:do_deploy as a task dependency here since the kernel size
+# needs to be known for generating the device tree.
+# Dependencies are only introduced if a device tree will be generated.
+QB_XEN_DTB_TASK_DEPENDS ?= " \
+    ${@[ ' \
+        qemu-helper-native:do_populate_sysroot \
+        lopper-native:do_populate_sysroot \
+        dtc-native:do_populate_sysroot \
+        virtual/kernel:do_deploy \
+    ', ''][d.getVar('QB_DTB') == '' or d.getVar('QB_DTB') is None]} \
+    "
+do_write_xen_qemuboot_dtb[depends] = "${QB_XEN_DTB_TASK_DEPENDS}"
+
+def qemuboot_dtb_vars(d):
+    build_vars = ['MACHINE', 'TUNE_ARCH', 'DEPLOY_DIR_IMAGE',
+                'KERNEL_IMAGETYPE', 'IMAGE_NAME', 'IMAGE_LINK_NAME',
+                'STAGING_DIR_NATIVE', 'STAGING_BINDIR_NATIVE',
+                'STAGING_DIR_HOST', 'SERIAL_CONSOLES']
+    return build_vars + [k for k in d.keys() if k.startswith('QB_')]
+
+do_write_qemuboot_dtb[vardeps] += "${@' '.join(qemuboot_dtb_vars(d))}"
+do_write_qemuboot_dtb[vardepsexclude] += "TOPDIR"