Method create_anonymous_file

vmm/src/memory_manager.rs:1843–1880

(
        size: usize,
        hugepages: bool,
        hugepage_size: Option<u64>,
    )

    }

    fn create_anonymous_file(
        size: usize,
        hugepages: bool,
        hugepage_size: Option<u64>,
    ) -> Result<FileOffset, Error> {
        let fd = Self::memfd_create(
            &ffi::CString::new("ch_ram").unwrap(),
            libc::MFD_CLOEXEC
                | if hugepages {
                    libc::MFD_HUGETLB
                        | if let Some(hugepage_size) = hugepage_size {
                            /*
                             * From the Linux kernel:
                             * Several system calls take a flag to request "hugetlb" huge pages.
                             * Without further specification, these system calls will use the
                             * system's default huge page size.  If a system supports multiple
                             * huge page sizes, the desired huge page size can be specified in
                             * bits [26:31] of the flag arguments.  The value in these 6 bits
                             * will encode the log2 of the huge page size.
                             */

                            hugepage_size.trailing_zeros() << 26
                        } else {
                            // Use the system default huge page size
                            0
                        }
                } else {
                    0
                },
        )
        .map_err(Error::SharedFileCreate)?;

        // SAFETY: fd is valid
        let f = unsafe { File::from_raw_fd(fd) };
        f.set_len(size as u64).map_err(Error::SharedFileSetLen)?;

        Ok(FileOffset::new(f, 0))
    }

    fn open_backing_file(
        backing_file: &PathBuf,