[PATCH v2 4/7] qemuriscv: Dynamically configure qemu CPU

Mark Hatle
2025-06-17T23:39:57Z

Use TUNE_FEATURES to dynamically configure the QEMU emulated CPU for the
options selected by the DEFAULTTUNE.

Note: OpenSBI currently requires 'c' (compressed instructions) or it will
not work.

Change the base device configuration to use a different variable to select
the emulate devices. This will allow a user to override or append the
QB_OPT_APPEND without the riscv32 override getting in the way.

Signed-off-by: Mark Hatle <mark.hatle@amd.com>
---
meta/conf/machine/include/riscv/qemuriscv.inc | 31 +++++++++++++++++--
1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/meta/conf/machine/include/riscv/qemuriscv.inc b/meta/conf/machine/include/riscv/qemuriscv.inc
index 65cbfd66ee..91a84cdd39 100644
--- a/meta/conf/machine/include/riscv/qemuriscv.inc
+++ b/meta/conf/machine/include/riscv/qemuriscv.inc
@@ -27,7 +27,6 @@ UBOOT_ENTRYPOINT:riscv64 = "0x80200000"
# qemuboot options
QB_SMP ?= "-smp 4"
QB_KERNEL_CMDLINE_APPEND = "earlycon=sbi"
-QB_CPU:riscv64 ?= "-cpu rva22s64"
QB_MACHINE = "-machine virt"
QB_DEFAULT_BIOS = "fw_jump.elf"
QB_TAP_OPT = "-netdev tap,id=net0,ifname=@TAP@,script=no,downscript=no"
@@ -36,5 +35,31 @@ QB_ROOTFS_OPT = "-drive id=disk0,file=@ROOTFS@,if=none,format=raw -device virtio
QB_SERIAL_OPT = "-device virtio-serial-device -chardev null,id=virtcon -device virtconsole,chardev=virtcon"
QB_TCPSERIAL_OPT = " -device virtio-serial-device -chardev socket,id=virtcon,port=@PORT@,host=127.0.0.1,nodelay=on -device virtconsole,chardev=virtcon"
QB_GRAPHICS = "-device bochs-display"
-QB_OPT_APPEND = "-device qemu-xhci -device usb-tablet -device usb-kbd"
-QB_OPT_APPEND:riscv32 = "-device virtio-tablet-pci -device virtio-keyboard-pci"
+QB_OPT_APPEND = "${RV_QEMU_ISA} ${RV_QEMU_DEVICES}"
+
+RV_QEMU_DEVICES = "-device qemu-xhci -device usb-tablet -device usb-kbd"
+RV_QEMU_DEVICES:riscv32 = "-device virtio-tablet-pci -device virtio-keyboard-pci"
+
+RV_QEMU_ISA = "-cpu "
+# Choose rv32 or rv64
+RV_QEMU_ISA .= "${@bb.utils.contains("TUNE_FEATURES", "rv 32", "rv32", "", d)}"
+RV_QEMU_ISA .= "${@bb.utils.contains("TUNE_FEATURES", "rv 64", "rv64", "", d)}"
+# Disable all of the default extensions we don't support
+RV_QEMU_ISA .= ",zihintntl=false,zihintpause=false,zawrs=false,zfa=false,svadu=false,zicntr=false,zihpm=false"
+RV_QEMU_ISA .= ",zicboz=false,zicbop=false,zmmul=false,sstc=false,h=false"
+# Dynamically enable the extensions based on TUNE_FEATURES
+RV_QEMU_ISA .= "${@bb.utils.contains ("TUNE_FEATURES", "m", ",m=true", ",m=false", d)}"
+RV_QEMU_ISA .= "${@bb.utils.contains ("TUNE_FEATURES", "a", ",a=true", ",a=false", d)}"
+RV_QEMU_ISA .= "${@bb.utils.contains_any("TUNE_FEATURES", "f d", ",f=true", ",f=false", d)}"
+RV_QEMU_ISA .= "${@bb.utils.contains ("TUNE_FEATURES", "d", ",d=true", ",d=false", d)}"
+# OpenSBI fails to boot without 'c'
+#RV_QEMU_ISA .= "${@bb.utils.contains ("TUNE_FEATURES", "c", ",c=true", ",c=false", d)}"
+RV_QEMU_ISA .= "${@bb.utils.contains ("TUNE_FEATURES", "v", ",v=true", ",v=false", d)}"
+RV_QEMU_ISA .= "${@bb.utils.contains ("TUNE_FEATURES", "zicbom", ",zicbom=true", ",zicbom=false", d)}"
+RV_QEMU_ISA .= "${@bb.utils.contains_any("TUNE_FEATURES", "zicsr f d", ",zicsr=true", ",zicsr=false", d)}"
+RV_QEMU_ISA .= "${@bb.utils.contains ("TUNE_FEATURES", "zifencei", ",zifencei=true", ",zifencei=false", d)}"
+RV_QEMU_ISA .= "${@bb.utils.contains_any("TUNE_FEATURES", "b zba", ",zba=true", ",zba=false", d)}"
+RV_QEMU_ISA .= "${@bb.utils.contains_any("TUNE_FEATURES", "b zbb", ",zbb=true", ",zbb=false", d)}"
+RV_QEMU_ISA .= "${@bb.utils.contains ("TUNE_FEATURES", "zbc", ",zbc=true", ",zbc=false", d)}"
+RV_QEMU_ISA .= "${@bb.utils.contains_any("TUNE_FEATURES", "b zbs", ",zbs=true", ",zbs=false", d)}"
+
--
2.34.1