Function receive_memory_ranges

vmm/src/migration_transport.rs:939–979

Receive memory contents for the given range table into guest memory.

(
    guest_memory: &GuestMemoryAtomic<GuestMemoryMmap>,
    req: &Request,
    socket: &mut SocketStream,
)

/// Receive memory contents for the given range table into guest memory.
pub(crate) fn receive_memory_ranges(
    guest_memory: &GuestMemoryAtomic<GuestMemoryMmap>,
    req: &Request,
    socket: &mut SocketStream,
) -> Result<(), MigratableError> {
    debug_assert_eq!(req.command(), Command::Memory);
    // Read the memory table
    let ranges = MemoryRangeTable::read_from(socket, req.length())?;

    // And then the memory itself
    let mem = guest_memory.memory();

    for range in ranges.regions() {
        let mut offset: u64 = 0;
        // Here we are manually handling the retry in case we can't read the
        // whole region at once because we can't use the implementation
        // from vm-memory::GuestMemory of read_exact_from() as it is not
        // following the correct behavior. For more info about this issue
        // see: https://github.com/rust-vmm/vm-memory/issues/174
        loop {
            let bytes_read = mem
                .read_volatile_from(
                    GuestAddress(range.gpa + offset),
                    socket,
                    (range.length - offset) as usize,
                )
                .map_err(|e| {
                    MigratableError::MigrateReceive(anyhow!(
                        "Error receiving memory from socket: {e}"
                    ))
                })?;
            offset += bytes_read as u64;

            if offset == range.length {
                break;
            }
        }
    }

    Ok(())
}