Comment 17 for bug 2012763

So this was apparently fixed in qemu 8.1.0:

commit e0001297eb2f8569e950e55dbda8ad686e4155fb
Author: Suravee Suthikulpanit <email address hidden>
Date: Wed Jun 7 15:57:17 2023 -0500

    pc: q35: Bump max_cpus to 1024

    Since KVM_MAX_VCPUS is currently defined to 1024 for x86 as shown in
    arch/x86/include/asm/kvm_host.h, update QEMU limits to the same number.

    In case KVM could not support the specified number of vcpus, QEMU would
    return the following error message:

      qemu-system-x86_64: kvm_init_vcpu: kvm_get_vcpu failed (xxx): Invalid argument

    Also, keep max_cpus at 288 for machine version 8.0 and older.

    Cc: Igor Mammedov <email address hidden>
    Cc: Daniel P. Berrangé <email address hidden>
    Cc: Michael S. Tsirkin <email address hidden>
    Cc: Julia Suvorova <email address hidden>
    Reviewed-by: Igor Mammedov <email address hidden>
    Signed-off-by: Suravee Suthikulpanit <email address hidden>
    Message-Id: <email address hidden>
    Reviewed-by: Michael S. Tsirkin <email address hidden>
    Signed-off-by: Michael S. Tsirkin <email address hidden>
    Reviewed-by: Daniel P. Berrangé <email address hidden>

$ git tag --contains e0001297eb2
v8.1.0
v8.1.0-rc0
v8.1.0-rc1
v8.1.0-rc2
v8.1.0-rc3
v8.1.0-rc4

Looking at rmadison, mantic only has 8.0.4:

 qemu | 1:8.0.4+dfsg-1ubuntu1 | mantic | source

Would it be possible to:

A: get mantic bumped to 8.1.0
B: work on getting this back to Jammy to unblock 22.04 certs? (well, for now we are just accepting failed VM tests because these larger CPUs have no support in Jammy due to the qemu-system-x86_64 max_cpu limitation.