Function run_shell 

pub fn run_shell(
    kernel: PathBuf,
    numa_nodes: u32,
    llcs: u32,
    cores: u32,
    threads: u32,
    include_files: &[(&str, &Path)],
    memory_mib: Option<u32>,
    dmesg: bool,
    exec: Option<&str>,
    exec_timeout: Duration,
    disk: Option<DiskConfig>,
    wprof_args: Option<&str>,
    performance_mode: bool,
    sched_enable_cmds: &[&str],
    sched_disable_cmds: &[&str],
) -> Result<Option<i32>>

Boot a KVM VM in interactive shell mode.

Builds an initramfs with busybox and optional include files, then launches a VM with bidirectional stdin/stdout forwarding. The guest runs a shell via busybox; user-provided files are available at /include-files/<name>.

kernel: path to the kernel image (bzImage/Image). numa_nodes, llcs, cores, threads: guest CPU topology. include_files: (archive_path, host_path) pairs for files to include in the guest. memory_mib: explicit guest memory override in MiB; conversion at VM-launch is value << 20 bytes. When None, memory is computed from actual initramfs size after build. disk: optional virtio-blk device backing for /dev/vda. When Some, the framework calls vmm::KtstrVm::builder’s .disk(..) so the guest probes a raw block device sized per disk.capacity_mib. wprof_args: requires the wprof cargo feature. When the feature is enabled and Some, replaces WprofConfig::args with the tokenised value before booting; None keeps the defaults. Without the feature, this parameter is ignored (a warning is emitted to stderr if Some). performance_mode: forwarded to vmm::KtstrVmBuilder::performance_mode; when true, the builder pins vCPU threads, applies hugepages, NUMA mbinds, and promotes vCPU threads to SCHED_FIFO (host-side optimizations). sched_enable_cmds / sched_disable_cmds: forwarded to vmm::KtstrVmBuilder::sched_enable_cmds / vmm::KtstrVmBuilder::sched_disable_cmds. Non-empty when the shell is reproducing a test whose scheduler is a test_support::SchedulerSpec::KernelBuiltin variant — guest init runs the enable cmds before drop-to-busybox and the disable cmds on shell exit, so the operator gets the same scheduler-loaded environment the test would see. Empty slices mean “no scheduler-lifecycle commands.”