Memory allocation fails on darwin arm64 with latest qemu

[afbjorklund]

Description

Starting the default with 4GiB fails:
qemu-system-aarch64: Addressing limited to 32 bits, but memory exceeds it by 1073741824 bytes

Need to reduce memory, to e.g. 2GiB.

Since qemu/qemu@3715c25

Most likely the highmem=off parameter to qemu should be parametrized, and not used with later versions.

The reasons that caused it to be needed (for ARM) earlier, seems to no longer be true with QEMU 7.0.

This was: QEMU emulator version 6.2.50 (v6.1.0-3974-gf6620d0b34-dirty)

[AkihiroSuda]

If this is a regression of QEMU, this should be perhaps fixed in the QEMU upstream?

[afbjorklund]

To be honest I am not sure, like where this extra "highmem" parameter comes from ?

It seems like it was needed before, due to limitations in the platform support.
But not any longer, however it is not parameterized at all in lima - but hardcoded.

        case limayaml.X8664:
                if strings.HasPrefix(cpu, "qemu64") {
...
                } else {
                        args = appendArgsIfNoConflict(args, "-machine", "q35,accel="+accel)
                }
        case limayaml.AARCH64:
                args = appendArgsIfNoConflict(args, "-machine", "virt,accel="+accel+",highmem=off")

I remember having to do similar arm64 workarounds before, it was 36 bits then 42 bits etc

[AkihiroSuda]

To be honest I am not sure, like where this extra "highmem" parameter comes from ?

• Make it working on Apple Silicon #24

cc @tarik02 Could you take a look? What should we do?

[afbjorklund]

It might have to be versioned, based on the QEMU version.

Haven't checked Linux/KVM yet, if it has the same issue there.
My RPi only has 4 GiB (total), but I could rent a cloud server...

I was thinking to make it a user-changeable option, at least ?

[tarik02]

cc @tarik02 Could you take a look? What should we do?

Sorry for offtop, will check this after we win war with russia.

[AkihiroSuda]

cc @tarik02 Could you take a look? What should we do?

Sorry for offtop, will check this after we win war with russia.

Sorry, I could have checked your profile before pinging you 🤦‍♂️
Hope you are staying safe! 🇺🇦