Function emulate_io 

pub async fn emulate_io(
    vp_index: VpIndex,
    is_write: bool,
    port: u16,
    rax: &mut u64,
    len: u8,
    dev: &impl CpuIo,
)

Emulates an IO port instruction.

Just handles calling into the IO bus and updating rax. The caller must update RIP, and it must update the VP’s rax register (when !is_write).

The caller is also responsible for performing any security checks to ensure the guest is allowed to execute I/O instructions. However, typically this is handled by the hardware and hypervisor automatically.