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.

template<typename ITER >
void	consumed (ITER const &begin, ITER const &end)
	Put multiple descriptors into the used ring.

template<typename QUEUE_OBSERVER >
void	finish (Head_desc &d, QUEUE_OBSERVER *o, l4_uint32_t len=0)
	Add a descriptor to the used ring, and notify an observer.

template<typename ITER , typename QUEUE_OBSERVER >
void	finish (ITER const &begin, ITER const &end, QUEUE_OBSERVER *o)
	Add a range of descriptors to the used ring, and notify an observer once.

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 ()=default
	Create a disabled virtqueue.

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

Avail *	_avail = nullptr
	pointer to available ring.

Used *	_used = nullptr
	pointer to used ring.

l4_uint16_t	_current_avail = 0
	The life counter for the queue.

l4_uint16_t	_idx_mask = 0
	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() [1/2]

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 171 of file virtio.

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

Referenced by finish(), finish(), and L4virtio::Svr::Console::Virtio_con::handle_control_message().

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◆ consumed() [2/2]

template<typename ITER >

void L4virtio::Svr::Virtqueue::consumed	(	ITER const &	begin,
		ITER const &	end
	)

inline

Put multiple descriptors into the used ring.

A range of descriptors, specified by begin and end iterators is added. Each iterator points to a struct that has a first member that is a Head_desc and a second member that is the corresponding number of bytes written.

Template Parameters

ITER	The type of the iterator (inferred).

Parameters

begin	Iterator pointing to first new descriptor.
end	Iterator pointing to one past last entry.

Precondition: queue must be in working state.

Definition at line 194 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 279 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 156 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 254 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 265 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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◆ finish() [1/2]

template<typename QUEUE_OBSERVER >

void L4virtio::Svr::Virtqueue::finish	(	Head_desc &	d,
		QUEUE_OBSERVER *	o,
		l4_uint32_t	len = `0`
	)

inline

Add a descriptor to the used ring, and notify an observer.

Template Parameters

QUEUE_OBSERVER The type of the observer (inferred).

Parameters

d	descriptor of the request that is to be marked as finished.
o	Pointer to the observer that is notified.
len	Number of bytes written for this request.

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

Definition at line 221 of file virtio.

References consumed().

Referenced by L4virtio::Svr::Console::Device::port_read(), L4virtio::Svr::Console::Device::port_write(), and L4virtio::Svr::Console::Virtio_con::send_control_message().

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◆ finish() [2/2]

template<typename ITER , typename QUEUE_OBSERVER >

void L4virtio::Svr::Virtqueue::finish	(	ITER const &	begin,
		ITER const &	end,
		QUEUE_OBSERVER *	o
	)

inline

Add a range of descriptors to the used ring, and notify an observer once.

The iterators are passed to consumed<ITER>(ITER const &, ITER const &), and the requirements detailed there apply.

Template Parameters

ITER	type of the iterator (inferred)
QUEUE_OBSERVER	the type of the observer (inferred).

Parameters

begin	iterator pointing to first element.
end	iterator pointing to one past last element.
o	pointer to the observer that is notified.

Precondition: queue must be in working state.

Definition at line 243 of file virtio.

References consumed().

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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 138 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.

Referenced by L4virtio::Svr::Block_dev_base< Ds_data >::get_request(), L4virtio::Svr::Console::Virtio_con::handle_control_message(), L4virtio::Svr::Console::Device::port_read(), L4virtio::Svr::Console::Device::port_write(), and L4virtio::Svr::Console::Virtio_con::send_control_message().

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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() [1/2]

◆ consumed() [2/2]

◆ desc()

◆ desc_avail()

◆ disable_notify()

◆ enable_notify()

◆ finish() [1/2]

◆ finish() [2/2]

◆ next_avail()