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vmm: memory_manager: Split filesystem backed and anonymous RAM creation
This simplifies the code somewhat making the code paths more readable. Signed-off-by: Rob Bradford <robert.bradford@intel.com>
This commit is contained in:
Rob Bradford
parent
ff3fb91ba6
commit
1e5a4e8d77
@ -1216,75 +1216,74 @@ impl MemoryManager {
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}
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}
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fn open_memory_file(
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backing_file: &Option<PathBuf>,
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file_offset: u64,
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fn create_anonymous_file(
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size: usize,
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hugepages: bool,
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hugepage_size: Option<u64>,
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) -> Result<FileOffset, Error> {
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let (f, f_off) = match backing_file {
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Some(ref file) => {
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if file.is_dir() {
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// Override file offset as it does not apply in this case.
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info!(
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"Ignoring file offset since the backing file is a \
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temporary file created from the specified directory."
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);
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let fs_str = format!("{}{}", file.display(), "/tmpfile_XXXXXX");
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let fs = ffi::CString::new(fs_str).unwrap();
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let mut path = fs.as_bytes_with_nul().to_owned();
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let path_ptr = path.as_mut_ptr() as *mut _;
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let fd = unsafe { libc::mkstemp(path_ptr) };
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unsafe { libc::unlink(path_ptr) };
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let f = unsafe { File::from_raw_fd(fd) };
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f.set_len(size as u64).map_err(Error::SharedFileSetLen)?;
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let fd = Self::memfd_create(
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&ffi::CString::new("ch_ram").unwrap(),
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libc::MFD_CLOEXEC
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| if hugepages {
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libc::MFD_HUGETLB
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| if let Some(hugepage_size) = hugepage_size {
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/*
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* From the Linux kernel:
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* Several system calls take a flag to request "hugetlb" huge pages.
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* Without further specification, these system calls will use the
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* system's default huge page size. If a system supports multiple
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* huge page sizes, the desired huge page size can be specified in
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* bits [26:31] of the flag arguments. The value in these 6 bits
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* will encode the log2 of the huge page size.
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*/
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(f, 0)
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hugepage_size.trailing_zeros() << 26
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} else {
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// Use the system default huge page size
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0
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}
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} else {
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let f = OpenOptions::new()
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.read(true)
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.write(true)
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.open(file)
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.map_err(Error::SharedFileCreate)?;
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0
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},
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)
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.map_err(Error::SharedFileCreate)?;
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(f, file_offset)
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}
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}
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None => {
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let flags = libc::MFD_CLOEXEC
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| if hugepages {
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libc::MFD_HUGETLB
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| if let Some(hugepage_size) = hugepage_size {
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/*
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* From the Linux kernel:
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* Several system calls take a flag to request "hugetlb" huge pages.
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* Without further specification, these system calls will use the
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* system's default huge page size. If a system supports multiple
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* huge page sizes, the desired huge page size can be specified in
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* bits [26:31] of the flag arguments. The value in these 6 bits
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* will encode the log2 of the huge page size.
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*/
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let f = unsafe { File::from_raw_fd(fd) };
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f.set_len(size as u64).map_err(Error::SharedFileSetLen)?;
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hugepage_size.trailing_zeros() << 26
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} else {
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// Use the system default huge page size
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0
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}
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} else {
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0
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};
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let fd = Self::memfd_create(&ffi::CString::new("ch_ram").unwrap(), flags)
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.map_err(Error::SharedFileCreate)?;
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Ok(FileOffset::new(f, 0))
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}
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let f = unsafe { File::from_raw_fd(fd) };
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f.set_len(size as u64).map_err(Error::SharedFileSetLen)?;
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fn open_backing_file(
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backing_file: &PathBuf,
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file_offset: u64,
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size: usize,
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) -> Result<FileOffset, Error> {
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if backing_file.is_dir() {
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// Override file offset as it does not apply in this case.
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info!(
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"Ignoring file offset since the backing file is a \
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temporary file created from the specified directory."
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);
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let fs_str = format!("{}{}", backing_file.display(), "/tmpfile_XXXXXX");
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let fs = ffi::CString::new(fs_str).unwrap();
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let mut path = fs.as_bytes_with_nul().to_owned();
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let path_ptr = path.as_mut_ptr() as *mut _;
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let fd = unsafe { libc::mkstemp(path_ptr) };
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unsafe { libc::unlink(path_ptr) };
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let f = unsafe { File::from_raw_fd(fd) };
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f.set_len(size as u64).map_err(Error::SharedFileSetLen)?;
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(f, 0)
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}
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};
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Ok(FileOffset::new(f, 0))
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} else {
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let f = OpenOptions::new()
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.read(true)
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.write(true)
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.open(backing_file)
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.map_err(Error::SharedFileCreate)?;
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Ok(FileOffset::new(f, f_off))
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Ok(FileOffset::new(f, file_offset))
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}
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}
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#[allow(clippy::too_many_arguments)]
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@ -1302,14 +1301,10 @@ impl MemoryManager {
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) -> Result<Arc<GuestRegionMmap>, Error> {
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let fo = if let Some(f) = existing_memory_file {
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Some(FileOffset::new(f, file_offset))
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} else if let Some(backing_file) = backing_file {
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Some(Self::open_backing_file(backing_file, file_offset, size)?)
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} else {
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Some(Self::open_memory_file(
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backing_file,
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file_offset,
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size,
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hugepages,
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hugepage_size,
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)?)
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Some(Self::create_anonymous_file(size, hugepages, hugepage_size)?)
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};
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let mut mmap_flags = libc::MAP_NORESERVE
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