VM Startup (QEMU RAM Allocation) Errors with High (>32GB) RAM on M2 Max Macbook

[Aeonitis]

When attempting to start a virtual machine using a large amount of RAM (e.g. 81,920MB or 65,536MB) on my physical 96GB RAM M2 Max MacBook through UTM, I intermittently receive one of two error messages. Purpose is to build Android OS code.

The first is:
QEMU error: QEMU exited from an error: qemu-aarch64-softmmu: Error: HV_BAD_ARGUMENT

and the second:
QEMU error: QEMU exited from an error: qemu-aarch64-softmmu: -drive if=none,media=cdrom,id=drive6EA5E6A4-0E92-4C50-9C56-405C793F1C8E,file=/Users/aeonitis/Downloads/ubuntu-22.04.2-live-server-arm64.iso,readonly=on: Could not open '/Users/aeonitis/Downloads/ubuntu-22.04.2-live-server-arm64.iso': Operation not permitted.

The issue does not persist when the RAM allocation is set to 32,768MB or less. Everything seems to run fine within that limit.

Additionally, upon inspecting the code, I noticed that the RAMSlider is limited to 32GB maximum. Considering modern Macs now support up to 192GB RAM, I suggest updating this slider for better alignment with the latest hardware capabilities. I stopped troubleshooting past going through the systemMemory variable which might also play a role in this limitation...

Configuration

• UTM Version: 4.3.5
• macOS Version: 13.5
• Mac Chip: M2 Max
• Storage: 300GB
• Cores: 20 out of 24

Sorry I can't provide logs as the folders didn't seem to produce them pre-boot I guess, and for some reason the mac app reporting popup stopped appearing. I'm kinda glad this is the case as I don't wanna share more private device data.

[osy]

@agraf Is there a HVF limitation on the amount of RAM that can be allocated?

[oscarbg]

nice!
seeing UTM picks patches from upstream, searching new hvf related commits up to Qemu 9.2:
https://github.com/search?q=repo%3Aqemu%2Fqemu+hvf&type=commits&s=committer-date&o=desc&p=1
seems there is another interesting (recent) one:
"i386/hvf: Integrates x2APIC support with hvf accel"
qemu/qemu@0e27f3a
"Enabling it when using macOS’s hvf
accelerator is useful and significantly helps performance, as Qemu
currently uses the emulated APIC when running on hvf as well."
don't know if real performance would be affected but I would be interested to be able to test..

[osy]

@oscarbg I thought you're on Apple Silicon? That change only applies to x86_64

[oscarbg]

yep.. stupid mistake.. forgot to read more about that change..

[Aeonitis]

Thank you!!! @oscarbg & @osy

So I guess it'll be available in v9.2.0 release right?