Virtqueue implementation for the device. More...

#include <virtio>

Inheritance diagram for L4virtio::Svr::Virtqueue:

Collaboration diagram for L4virtio::Svr::Virtqueue:

Data Structures
class	Head_desc
	VIRTIO request, essentially a descriptor from the available ring. More...

Public Member Functions
Request	next_avail ()
	Get the next available descriptor from the available ring.

bool	desc_avail () const
	Test for available descriptors.

void	consumed (Head_desc const &r, l4_uint32_t len=0)
	Put the given descriptor into the used ring.

void	disable_notify ()
	Set the 'no notify' flag for this queue.

void	enable_notify ()
	Clear the 'no notify' flag for this queue.

Desc const *	desc (unsigned idx) const
	Get a descriptor from the descriptor list.

Public Member Functions inherited from L4virtio::Virtqueue
void	disable ()
	Completely disable the queue.

unsigned long	total_size () const
	Calculate the total size of this virtqueue.

unsigned long	avail_offset () const
	Get the offset of the available ring from the descriptor table.

unsigned long	used_offset () const
	Get the offset of the used ring from the descriptor table.

void	setup (unsigned num, void desc, void avail, void *used)
	Enable this queue.

void	setup_simple (unsigned num, void *ring)
	Enable this queue.

void	dump (Desc const *d) const
	Dump descriptors for this queue.

bool	ready () const
	Test if this queue is in working state.

unsigned	num () const

bool	no_notify_guest () const
	Get the no IRQ flag of this queue.

bool	no_notify_host () const
	Get the no notify flag of this queue.

void	no_notify_host (bool value)
	Set the no-notify flag for this queue.

l4_uint16_t	get_avail_idx () const
	Get available index from available ring (for debugging).

l4_uint16_t	get_tail_avail_idx () const
	Get tail-available index stored in local state (for debugging).

Additional Inherited Members
Public Types inherited from L4virtio::Virtqueue
enum
	Fixed alignment values for different parts of a virtqueue.

Static Public Member Functions inherited from L4virtio::Virtqueue
static unsigned long	total_size (unsigned num)
	Calculate the total size for a virtqueue of the given dimensions.

static unsigned long	desc_size (unsigned num)
	Calculate the size of the descriptor table for `num` entries.

static unsigned long	desc_align ()
	Get the alignment in zero LSBs needed for the descriptor table.

static unsigned long	avail_size (unsigned num)
	Calculate the size of the available ring for `num` entries.

static unsigned long	avail_align ()
	Get the alignment in zero LSBs needed for the available ring.

static unsigned long	used_size (unsigned num)
	Calculate the size of the used ring for `num` entries.

static unsigned long	used_align ()
	Get the alignment in zero LSBs needed for the used ring.

Protected Member Functions inherited from L4virtio::Virtqueue
	Virtqueue ()
	Create a disabled virtqueue.

Protected Attributes inherited from L4virtio::Virtqueue
Desc *	_desc
	pointer to descriptor table, NULL if queue is off.

Avail *	_avail
	pointer to available ring.

Used *	_used
	pointer to used ring.

l4_uint16_t	_current_avail
	The life counter for the queue.

l4_uint16_t	_idx_mask
	mask used for indexing into the descriptor table and the rings.

Detailed Description

Virtqueue implementation for the device.

This class represents a single virtqueue, with a local running available index.

Note: The Virtqueue implementation is not thread-safe.

Definition at line 87 of file virtio.

Member Function Documentation

◆ consumed()

void L4virtio::Svr::Virtqueue::consumed	(	Head_desc const &	r,
		l4_uint32_t	len = `0`
	)

inline

Put the given descriptor into the used ring.

Parameters

r	request that shall be marked as finished.
len	the total number of bytes written.

Precondition: queue must be in working state.; r must be a valid request from this queue.

Definition at line 166 of file virtio.

References L4virtio::Virtqueue::_desc, L4virtio::Virtqueue::_idx_mask, L4virtio::Virtqueue::_used, L4virtio::Virtqueue::Used::idx, and L4virtio::Virtqueue::Used::ring.

◆ desc()

Desc const * L4virtio::Svr::Virtqueue::desc ( unsigned idx ) const

inline

Get a descriptor from the descriptor list.

Parameters

idx	the index of the descriptor.

Precondition: idx < num; queue must be in working state

Definition at line 231 of file virtio.

References L4virtio::Virtqueue::_desc.

Referenced by L4virtio::Svr::Request_processor::start().

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◆ desc_avail()

bool L4virtio::Svr::Virtqueue::desc_avail ( ) const

inline

Test for available descriptors.

Returns: true if there are descriptors available, false if not.

Precondition: The queue must be in working state.

Definition at line 154 of file virtio.

References L4virtio::Virtqueue::_avail, L4virtio::Virtqueue::_current_avail, and L4virtio::Virtqueue::Avail::idx.

◆ disable_notify()

void L4virtio::Svr::Virtqueue::disable_notify ( )

inline

Set the 'no notify' flag for this queue.

This function may be called on a disabled queue.

Definition at line 208 of file virtio.

References L4virtio::Virtqueue::_used, L4virtio::Virtqueue::Used::flags, L4_LIKELY, L4virtio::Virtqueue::Used::Flags::no_notify(), and L4virtio::Virtqueue::ready().

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◆ enable_notify()

void L4virtio::Svr::Virtqueue::enable_notify ( )

inline

Clear the 'no notify' flag for this queue.

This function may be called on a disabled queue.

Definition at line 219 of file virtio.

References L4virtio::Virtqueue::_used, L4virtio::Virtqueue::Used::flags, L4_LIKELY, L4virtio::Virtqueue::Used::Flags::no_notify(), and L4virtio::Virtqueue::ready().

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◆ next_avail()

Request L4virtio::Svr::Virtqueue::next_avail ( )

inline

Get the next available descriptor from the available ring.

Precondition: The queue must be in working state.

Returns: A Request for the next available descriptor, the Request is invalid if there are no descriptors in the available ring.

Note: The return value must be checked even when a previous desc_avail() returned true.

Definition at line 137 of file virtio.

References L4virtio::Virtqueue::_avail, L4virtio::Virtqueue::_current_avail, L4virtio::Virtqueue::_idx_mask, L4virtio::Virtqueue::Avail::idx, L4_LIKELY, and L4virtio::Virtqueue::Avail::ring.

The documentation for this class was generated from the following file:

l4/l4virtio/server/virtio

Data Structures

Public Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ consumed()

◆ desc()

◆ desc_avail()

◆ disable_notify()

◆ enable_notify()

◆ next_avail()