RISCV64 build fails to start in Qemu

[tresf]

Question

Running the nightly build of OpenJDK 21 fails to start in Qemu using the virt machine type.

• ✅ /usr/lib/jvm/java-11-openjdk-riscv64/bin/java --version (Zero VM)
• 🚫 /usr/lib/jvm/java-17-openjdk-riscv64/bin/java --version "Unsupported satp mode"
• 🚫 /usr/lib/jvm/java-21-openjdk-riscv64/bin/java --version "fatal / java.lang.System.registerNatives()"
• 🚫 ~/temurin/jdk-21.0.1+12/bin/java --version "fatal / java.lang.System.registerNatives()"

Logs: https://gist.github.com/tresf/3c9672633fe664b9dd170f2983cea566

• Are there instructions sets missing from virt that OpenJDK 21 for RISCV64 is expecting? If so, should I switch to a different machine type? (See "Board-specific documentation" below)
• Is this issue related to library or dependency?
• This same issue occurs running the fizzed binaries here, does this suggest I'm doing something wrong? https://github.com/fizzed/nitro

Qemu offers several hardware emulations, quoting:

Board-specific documentation

• Unfortunately many of the RISC-V boards QEMU supports are currently undocumented; you can get a complete list by running qemu-system-riscv64 --machine help, or qemu-system-riscv32 --machine help.
  • Microchip PolarFire SoC Icicle Kit (microchip-icicle-kit)
  • Shakti C Reference Platform (shakti_c)
  • SiFive HiFive Unleashed (sifive_u)
  • ‘virt’ Generic Virtual Platform (virt)

Context

Java version:

OpenJDK21U-jdk_riscv64_linux_hotspot_ea_21-0-1-12.tar.gz

Your operating system and platform:

uname -a

Linux debian 6.1.0-1-riscv64 #1 SMP Debian 6.1.4-1 (2023-01-07) riscv64 GNU/Linux

/etc/os-release

PRETTY_NAME="Debian GNU/Linux trixie/sid"
NAME="Debian GNU/Linux"
VERSION_CODENAME=trixie
...

Linking #664

[tresf]

Installing OpenJDK 17 actually gave a usable error and I was able to fix this:

Unsupported satp mode: sv57. Only satp modes up to sv48 are supported for now.

According to this mailing list thread, fixing this requires compiling Qemu, but fortunately newer Qemu versions were patched to allow a new flag:

qemu-system-riscv64 \
...
- -cpu rv64 \
+ -cpu rv64,sv57=off \