10.0.0 HVF x86_64 regression: can't boot NetBSD 10.1 with -smp 2
Host environment
- Operating system: macOS 15.4.1
- OS/kernel version: Darwin pet-power-plant 24.4.0 Darwin Kernel Version 24.4.0: Fri Apr 11 18:28:23 PDT 2025; root:xnu-11417.101.15~117/RELEASE_X86_64 x86_64
- Architecture: x86_64
- QEMU flavor: qemu-system-x86_64
- QEMU version: 10.0.0 (built from pkgsrc)
- QEMU command line:
qemu-system-x86_64 -accel hvf -smp 2 -nodefaults -nographic -serial mon:stdio -drive file=netbsd10-amd64.qcow2,if=virtio,index=0
Emulated/Virtualized environment
- Operating system: NetBSD 10.1
- OS/kernel version: NetBSD netbsd10-amd64.pet-power-plant.local 10.1 NetBSD 10.1 (GENERIC) #0: Mon Dec 16 13:08:11 UTC 2024 mkrepro@mkrepro.NetBSD.org:/usr/src/sys/arch/amd64/compile/GENERIC amd64
- Architecture: amd64
Description of problem
Under 9.2.3, a NetBSD/amd64 10.1 guest with -smp 2 booted and ran fine.
Under 10.0.0, the same guest never finishes loading the kernel. It looks like it's retrying many times per second, possibly even reloading the NetBSD boot loader each time, though it's redrawing so fast I can't tell for sure. (I'll attempt to link to an asciinema capture shortly.) -smp 1 lets the machine come up.
For comparison, a NetBSD/aarch64 10.1 with -smp 4 runs with -accel hvf under macOS/aarch64 15.4.1 just as well with 10.0.0 as it did with 9.2.3.
Steps to reproduce
- With x86 macOS host and NetBSD guest (possibly a wider range than the exact versions I'm currently using), attempt to boot NetBSD with
-smp 2