Create 2024-07-07-qemu_linux_61.md

_posts/2024-07-07-qemu_linux_61.md

@@ -0,0 +1,184 @@
+---
+layout: post
+title:  "Qemu for arm64 android kernel version 6.1"
+subtitle: "A way to run the latest android kernel what you want"
+header-img: img/post-bg-coffee.jpeg
+date:   2024-07-07 08:55:59
+author: half cup coffee
+catalog: true
+tags:	
+    - Linux
+    - Android
+    - Qemu
+---
+
+Before you start to follow this guide. You might need to read this [link](https://huangweiliang.github.io/2022/09/30/qemu-android-kernel/) first.
+
+
+# Fetch the android kernel version 6.1
+
+From this Google [link](https://source.android.com/docs/devices/cuttlefish/kernel-dev) we can get to know the branch inforamtion of android kernel.
+
+~~~
+ mkdir android-kernel && cd android-kernel
+ repo init -u https://android.googlesource.com/kernel/manifest -b common-android14-6.1-lts
+ repo sync -c -d -j8
+~~~
+
+# Build kernel and modules
+
+## Necessary change need be done before build
+
+For the folder common which is the kernel source code location.  Please do following change:
+
+~~~
+diff --git a/arch/arm64/configs/gki_defconfig b/arch/arm64/configs/gki_defconfig
+index bc18ada0bd54..eeab358fa3ed 100644
+--- a/arch/arm64/configs/gki_defconfig
++++ b/arch/arm64/configs/gki_defconfig
+@@ -744,3 +744,17 @@ CONFIG_KUNIT=y
+ CONFIG_KUNIT_DEBUGFS=y
+ # CONFIG_KUNIT_DEFAULT_ENABLED is not set
+ # CONFIG_RUNTIME_TESTING_MENU is not set
++
++CONFIG_INITRAMFS_SOURCE="/media/nvme1/temp/rootfs/rfs"
++CONFIG_VIRTIO_PCI=y
++CONFIG_VIRTIO_BALLOON=y
++CONFIG_VIRTIO_BLK=y
++CONFIG_VIRTIO_NET=y
++CONFIG_9P_FS_SECURITY=y
++CONFIG_NET_9P=y
++CONFIG_NET_9P_VIRTIO=y
++CONFIG_NET_9P_DEBUG=y
++CONFIG_9P_FS=y
++CONFIG_9P_FS_POSIX_ACL=y
++
++
+diff --git a/build.config.gki b/build.config.gki
+index 4b931d9eb333..da87a30d24e8 100644
+--- a/build.config.gki
++++ b/build.config.gki
+@@ -1,2 +1,2 @@
+ DEFCONFIG=gki_defconfig
+-POST_DEFCONFIG_CMDS="check_defconfig"
++###POST_DEFCONFIG_CMDS="check_defconfig"
+
+~~~
+
+## Build commands
+
+Execute below commands to build kernel and modules:
+
+~~~
+tools/bazel run //common:kernel_aarch64_dist -- --dist_dir=/media/nvme1/play_android_kernel/out-new
+tools/bazel run //common-modules/virtual-device:virtual_device_aarch64_dist  -- --dist_dir=/media/nvme1/play_android_kernel/out-new
+~~~
+
+# Adding a kernel module example
+
+The kernel build currently is using the Bazel. You can see the document about it from [here] (https://android.googlesource.com/kernel/build/+/refs/heads/main/kleaf/docs/impl.md).  So there is a differnet way for us to add a kernel module.
+
+For example, we have 2 new kernel module to be add.  We create the source code folder under common-modules/virtual-device.
+The folder device_test1 and hello-world-module is the 2 modules we are going to add.
+
+To compile these 2 kernel modules we need do following change :
+
+~~~
+diff --git a/BUILD.bazel b/BUILD.bazel
+index b01e18c..8f285de 100644
+--- a/BUILD.bazel
++++ b/BUILD.bazel
+@@ -92,6 +92,20 @@ filegroup(
+     ],
+ )
+
++filegroup(
++    name = "hello_world_sources",
++    srcs = [
++        "hello-world-module/hello-world-module.c"
++    ],
++)
++
++filegroup(
++    name = "device_test1_sources",
++    srcs = [
++        "device_test1/main.c"
++    ],
++)
++
+ filegroup(
+     name = "v4l2loopback_sources",
+     srcs = [
+@@ -517,6 +531,24 @@ ddk_module(
+     deps = [":common_headers_aarch64"],
+ )
+
++ddk_module(
++    name = "aarch64/hello_world",
++    srcs = [":hello_world_sources"],
++    out = "hello_world.ko",
++    kernel_build = ":virtual_device_aarch64",
++    local_defines = ["DRIVER_VERSION=\"android14-6.1\""],
++    deps = [":common_headers_aarch64"],
++)
++
++ddk_module(
++    name = "aarch64/device_test1",
++    srcs = [":device_test1_sources"],
++    out = "device_test1.ko",
++    kernel_build = ":virtual_device_aarch64",
++    local_defines = ["DRIVER_VERSION=\"android14-6.1\""],
++    deps = [":common_headers_aarch64"],
++)
++
+ ddk_module(
+     name = "aarch64/v4l2loopback",
+     srcs = [":v4l2loopback_sources"],
+@@ -534,6 +566,8 @@ kernel_module_group(
+         ":aarch64/goldfish_drivers/goldfish_sync",
+         ":aarch64/v4l2loopback",
+         ":aarch64/virtio_video",
++        ":aarch64/hello_world",
++        ":aarch64/device_test1",
+     ],
+ )
+
+~~~
+
+Then run the build command again. Then you will see the device_test1.ko and hello_world.ko in the folder /media/nvme1/play_android_kernel/out-new.
+
+# Launch the kernel
+
+Basically the command is like the command from this [link](https://huangweiliang.github.io/2022/09/30/qemu-android-kernel/).
+
+~~~
+export OUT_FOLDER="/media/nvme1/play_android_kernel/out-new"
+qemu-system-aarch64 -machine virt -cpu cortex-a57 -machine type=virt  -m 1024 -smp 4 -kernel $OUT_FOLDER/Image --append "rdinit=/linuxrc root=/dev/vda rw console=ttyAMA0 loglevel=8"  -nographic  -fsdev local,security_model=passthrough,id=fsdev0,path=$OUT_FOLDER  -device virtio-9p-pci,id=fs0,fsdev=fsdev0,mount_tag=kmod_mount  -drive format=raw,file=/media/nvme1/temp/rootfs/hd1 -net nic,model=virtio,macaddr=DE:AD:BE:EF:28:05
+~~~
+
+## Load the modules
+
+The folder play_android_kernel/out-new is passed to the qemu VM by the option *-fsdev local,security_model=passthrough,id=fsdev0,path=$OUT_FOLDER  -device virtio-9p-pci,id=fs0,fsdev=fsdev0,mount_tag=kmod_mount*. So all the files under the play_android_kernel/out-new can be seen in the guest VM after we launch it. It is mounted in the folder /mnt.
+
+To load the kernel module we created:
+
+~~~
+[root@weller mnt]# insmod hello_world.ko
+[   28.894159][   T90] hello_world: loading out-of-tree module taints kernel.
+[   28.894707][   T90] hello_world: module license 'MIT' taints kernel.
+[   28.894816][   T90] Disabling lock debugging due to kernel taint
+[   28.896604][   T90] hello_world: module verification failed: signature and/or required key missing - tainting kernel
+[   28.902241][   T90] [hello-world-module] Kernel Module Inserted Successfully...
+[root@weller mnt]# insmod device_test1.ko
+[   35.515065][   T91] ========mynull_device_init: In init
+[   35.515318][   T91] mynull_device_init: Major Number:503      Minor Number:0
+[root@weller mnt]#
+[root@weller mnt]# lsmod
+device_test1 20480 0 - Live 0xffffffc001026000 (OE)
+hello_world 20480 0 - Live 0xffffffc001020000 (POE)
+
+~~~
+
+Run poweroff command to exit from the Qemu.
+
+--END