id = 2665
title = "target/arm: cannot boot when CPU supports SME"
state = "closed"
created_at = "2024-11-11T05:18:05.252Z"
closed_at = "2025-03-03T12:11:47.718Z"
labels = ["accel: HVF", "hostos: macOS", "target: arm"]
url = "https://gitlab.com/qemu-project/qemu/-/issues/2665"
host-os = "macOS"
host-arch = "ARM64 (Apple M4)"
qemu-version = "main branch"
guest-os = "any"
guest-arch = "ARM64"
description = """On macOS 15.2 beta, Apple's Hypervisor.framework exposes the SME feat flag to QEMU. As a result, in `arm_cpu_sme_finalize`, `cpu_isar_feature(aa64_sme, cpu)` returns true and the program will always exit with the following:

```
qemu-aarch64-softmmu: cannot disable sme4224
All SME vector lengths are disabled.
With SME enabled, at least one vector length must be enabled.
```

This is because `vq_supported` and `vq_init` are both 0 as they are not initialized anywhere. It seems that in the original commit e74c097638d38b46d9c68f11565432034afc0ad0 the only place `cpu->sme_vq.supported` is initialized is with `aarch64_max_initfn` when KVM and HVF are not used as the backend."""
reproduce = "n/a"
additional = "n/a"