On Wed, Jul 1, 2026 at 7:58 AM Alex Kiernan via lists.openembedded.org <[email protected]> wrote: > > Add a QEMU machine for exercising an AArch32-only ARMv8-A target > (Cortex-A32) under emulation, defaulting to the cortexa32-crypto tune. > QEMU has no Cortex-A32 model, so it runs on the 'virt' machine with > qemu-system-arm and -cpu max, which provides the ARMv8-A AArch32 feature > set including the crypto extensions needed by the crypto tune. The kernel > is built as a zImage and u-boot uses qemu_arm_defconfig, matching the > other 32-bit ARM QEMU machines. > > Map KMACHINE to qemuarma15 so the existing linux-yocto BSP is reused, and > add qemuarmv8a32 to linux-yocto's COMPATIBLE_MACHINE so a kernel can be > built for it. > > AI-Generated: Claude Code (Claude Opus 4.8) > Signed-off-by: Alex Kiernan <[email protected]> > Signed-off-by: Alex Kiernan <[email protected]> > --- > meta/conf/machine/qemuarmv8a32.conf | 36 > +++++++++++++++++++++++++++ > meta/recipes-kernel/linux/linux-yocto_6.18.bb | 2 +- > 2 files changed, 37 insertions(+), 1 deletion(-) > > diff --git a/meta/conf/machine/qemuarmv8a32.conf > b/meta/conf/machine/qemuarmv8a32.conf > new file mode 100644 > index 000000000000..8e49a56ae720 > --- /dev/null > +++ b/meta/conf/machine/qemuarmv8a32.conf > @@ -0,0 +1,36 @@ > +#@TYPE: Machine > +#@NAME: QEMU ARMv8 AArch32 machine on Cortex-A32 > +#@DESCRIPTION: Machine configuration for running an AArch32 system on QEMU > + > +DEFAULTTUNE = "cortexa32-crypto" > + > +require conf/machine/include/arm/armv8a/tune-cortexa32.inc > +require conf/machine/include/qemu.inc > + > +KERNEL_IMAGETYPE = "zImage" > + > +PREFERRED_PROVIDER_virtual/bootloader ?= "u-boot" > +UBOOT_MACHINE ?= "qemu_arm_defconfig" > + > +SERIAL_CONSOLES ?= "115200;ttyAMA0 115200;hvc0" > + > +# For runqemu > +QB_SYSTEM_NAME = "qemu-system-arm" > +QB_MACHINE = "-machine virt" > +# QEMU doesn't know about Cortex-A32 > +QB_CPU = "-cpu max"
I have concerns that this isn't doing what is expected. Looking at qemu-system-arm -machine virt -cpu I'm seeing ... cortex-a15 cortex-a7 cortex-a8 cortex-a9 ... and not any of the armv8 cores. So, I think that you aren't going to get any of the ARMv8 features with 'max', despite them possibly being in the tune referenced above, which might cause crashes or other unintended issues. You might be okay on qemu-system-aarch64, given the ARMv8 cores there. Maybe you can try emulating the cortex-a35 core and running it in 32bit mode If I'm wrong, please provide a link to the documentation stating that max on qemu-system-arm does what you say, because I'm not seeing it on https://www.qemu.org/docs/master/system/arm/virt.html Thanks, Jon > +QB_SMP ?= "-smp 4" > +QB_CPU_KVM = "-cpu host -machine gic-version=3" > +# For graphics to work we need to define the VGA device as well as the > necessary USB devices > +QB_GRAPHICS = "-device virtio-gpu-pci" > +QB_OPT_APPEND = "-device qemu-xhci -device usb-tablet -device usb-kbd" > +# Virtio Networking support > +QB_TAP_OPT = "-netdev tap,id=net0,ifname=@TAP@,script=no,downscript=no" > +QB_NETWORK_DEVICE = "-device virtio-net-pci,netdev=net0,mac=@MAC@" > +# Virtio block device > +QB_ROOTFS_OPT = "-drive id=disk0,file=@ROOTFS@,if=none,format=raw -device > virtio-blk-pci,drive=disk0" > +# Virtio serial console > +QB_SERIAL_OPT = "-device virtio-serial-pci -chardev null,id=virtcon -device > virtconsole,chardev=virtcon" > +QB_TCPSERIAL_OPT = "-device virtio-serial-pci -chardev > socket,id=virtcon,port=@PORT@,host=127.0.0.1,nodelay=on -device > virtconsole,chardev=virtcon" > + > +KMACHINE:qemuarmv8a32 = "qemuarma15" > diff --git a/meta/recipes-kernel/linux/linux-yocto_6.18.bb > b/meta/recipes-kernel/linux/linux-yocto_6.18.bb > index 2b1298dedf9c..a818506bb6f3 100644 > --- a/meta/recipes-kernel/linux/linux-yocto_6.18.bb > +++ b/meta/recipes-kernel/linux/linux-yocto_6.18.bb > @@ -52,7 +52,7 @@ KCONF_BSP_AUDIT_LEVEL = "1" > > KERNEL_DEVICETREE:qemuarmv5 = "arm/versatile-pb.dtb" > > -COMPATIBLE_MACHINE = > "^(qemuarm|qemuarmv5|qemuarm64|qemux86|qemuppc|qemuppc64|qemumips|qemumips64|qemux86-64|qemuriscv64|qemuriscv32|qemuloongarch64)$" > +COMPATIBLE_MACHINE = > "^(qemuarm|qemuarmv5|qemuarmv8a32|qemuarm64|qemux86|qemuppc|qemuppc64|qemumips|qemumips64|qemux86-64|qemuriscv64|qemuriscv32|qemuloongarch64)$" > > # Functionality flags > KERNEL_EXTRA_FEATURES ?= "features/netfilter/netfilter.scc" > > -- > 2.43.0 > > > >
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