Struct IoVecBufferMut 

pub struct IoVecBufferMut<const L: u16 = FIRECRACKER_MAX_QUEUE_SIZE> {
    pub vecs: IovDeque<L>,
    pub len: u32,
}

This is essentially a wrapper of a Vec<libc::iovec> which can be passed to libc::readv.

It describes a write-only buffer passed to us by the guest that is scattered across multiple memory regions. Additionally, this wrapper provides methods that allow reading arbitrary ranges of data from that buffer. L const generic value must be a multiple of 256 as required by the IovDeque requirements.

Fields

vecs: IovDeque<L>

len: u32

Implementations

impl<const L: u16> IoVecBufferMut<L>

pub unsafe fn append_descriptor_chain( &mut self, mem: &GuestMemoryMmap, head: DescriptorChain, ) -> Result<ParsedDescriptorChain, IoVecError>

Append a DescriptorChain in this IoVecBufferMut

Safety

The descriptor chain cannot be referencing the same memory location as another chain

pub fn new() -> Result<Self, IovDequeError>

Create an empty IoVecBufferMut.

pub unsafe fn load_descriptor_chain( &mut self, mem: &GuestMemoryMmap, head: DescriptorChain, ) -> Result<(), IoVecError>

Create an IoVecBufferMut from a DescriptorChain

This will clear any previous iovec objects in the buffer and load the new DescriptorChain.

Safety

The descriptor chain cannot be referencing the same memory location as another chain

pub fn drop_chain_front(&mut self, parse_descriptor: &ParsedDescriptorChain)

Drop descriptor chain from the IoVecBufferMut front

This will drop memory described by the IoVecBufferMut from the beginning.

pub fn drop_chain_back(&mut self, parse_descriptor: &ParsedDescriptorChain)

Drop descriptor chain from the IoVecBufferMut back

This will drop memory described by the IoVecBufferMut from the beginning.

pub unsafe fn from_descriptor_chain( mem: &GuestMemoryMmap, head: DescriptorChain, ) -> Result<Self, IoVecError>

Create an IoVecBuffer from a DescriptorChain

Safety

The descriptor chain cannot be referencing the same memory location as another chain

pub fn len(&self) -> u32

Get the total length of the memory regions covered by this IoVecBuffer

pub fn is_empty(&self) -> bool

Returns true if buffer is empty.

pub fn as_iovec_mut_slice(&mut self) -> &mut [iovec]

Returns a pointer to the memory keeping the iovec structs

pub fn clear(&mut self)

Clears the iovec array

pub fn write_all_volatile_at( &mut self, buf: &[u8], offset: usize, ) -> Result<(), VolatileMemoryError>

Writes a number of bytes into the IoVecBufferMut starting at a given offset.

This will try to fill IoVecBufferMut writing bytes from the buf starting from the given offset. It will write as many bytes from buf as they fit inside the IoVecBufferMut starting from offset.

Returns

Ok(()) if the entire contents of buf could be written to this IoVecBufferMut, Err(VolatileMemoryError::PartialBuffer) if only part of buf could be transferred, and Err(VolatileMemoryError::OutOfBounds) if offset >= self.len().

pub fn write_volatile_at<W: ReadVolatile>( &mut self, src: &mut W, offset: usize, len: usize, ) -> Result<usize, VolatileMemoryError>

Writes up to len bytes into the IoVecBuffer starting at the given offset.

This will try to write to the given [WriteVolatile].

Trait Implementations

impl<const L: u16> Debug for IoVecBufferMut<L>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<const L: u16> Send for IoVecBufferMut<L>