#include <virtqueue>

Inheritance diagram for L4virtio::Virtqueue:

Collaboration diagram for L4virtio::Virtqueue:

Data Structures
class	Desc
	Descriptor in the descriptor table. More...
class	Avail
	Type of available ring, this is read-only for the host. More...
struct	Used_elem
	Type of an element of the used ring. More...
class	Used
	Used ring. More...

Public Types
enum
	Fixed alignment values for different parts of a virtqueue.

Public Member Functions
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, L4Re::Util::Dbg msg_dev=L4Re::Util::Dbg{2})
	Enable this queue.
void	setup_simple (unsigned num, void *ring, L4Re::Util::Dbg msg_dev=L4Re::Util::Dbg{2})
	Enable this queue.
void	dump (Desc const *d, L4Re::Util::Dbg dbg=L4Re::Util::Dbg{}) const
	Dump a descriptor 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).

Static Public Member Functions
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
	Virtqueue ()=default
	Create a disabled virtqueue.

Protected Attributes
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

Low-level Virtqueue.

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

Note: The Virtqueue implementation is not thread-safe.

Definition at line 86 of file virtqueue.

Member Function Documentation

◆ avail_align()

unsigned long L4virtio::Virtqueue::avail_align ( )

inlinestatic

Get the alignment in zero LSBs needed for the available ring.

Returns: The alignment in zero LSBs needed for an available ring.

Definition at line 295 of file virtqueue.

◆ avail_size()

unsigned long L4virtio::Virtqueue::avail_size ( unsigned num )

inlinestatic

Calculate the size of the available ring for num entries.

Parameters

num	The number of entries in the available ring.

Returns: The size in bytes needed for an available ring with num entries.

Definition at line 287 of file virtqueue.

References num().

Referenced by L4virtio::Svr::Device_t< No_custom_data >::setup_queue(), and total_size().

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◆ desc_align()

unsigned long L4virtio::Virtqueue::desc_align ( )

inlinestatic

Get the alignment in zero LSBs needed for the descriptor table.

Returns: The alignment in zero LSBs needed for a descriptor table.

Definition at line 277 of file virtqueue.

◆ desc_size()

unsigned long L4virtio::Virtqueue::desc_size ( unsigned num )

inlinestatic

Calculate the size of the descriptor table for num entries.

Parameters

num	The number of entries in the descriptor table.

Returns: The size in bytes needed for a descriptor table with num entries.

Definition at line 269 of file virtqueue.

References num().

Referenced by L4virtio::Svr::Device_t< No_custom_data >::setup_queue(), and total_size().

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◆ disable()

void L4virtio::Virtqueue::disable ( )

inline

Completely disable the queue.

setup() must be used to enable the queue again.

Definition at line 232 of file virtqueue.

References _desc.

Referenced by L4virtio::Svr::Device_t< No_custom_data >::setup_queue().

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◆ dump()

void L4virtio::Virtqueue::dump	(	Desc const *	d,
		L4Re::Util::Dbg	dbg = L4Re::Util::Dbg{} ) const

inline

Dump a descriptor for this queue.

Parameters

d	Descriptor pointer.
dbg	Debug channel for printing the information.

Precondition: the queue must be in working state.

Definition at line 409 of file virtqueue.

◆ get_avail_idx()

l4_uint16_t L4virtio::Virtqueue::get_avail_idx ( ) const

inline

Get available index from available ring (for debugging).

Precondition: Queue must be in a working state.

Returns: current index in the available ring (shared between device model and device driver).

Definition at line 468 of file virtqueue.

References _avail.

◆ get_tail_avail_idx()

l4_uint16_t L4virtio::Virtqueue::get_tail_avail_idx ( ) const

inline

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

Returns: current tail index for the the available ring.

Definition at line 475 of file virtqueue.

References _current_avail.

◆ no_notify_guest()

bool L4virtio::Virtqueue::no_notify_guest ( ) const

inline

Get the no IRQ flag of this queue.

Precondition: queue must be in working state.

Returns: true if the guest does not want to get IRQs (currently).

Definition at line 431 of file virtqueue.

References _avail.

Referenced by L4virtio::Svr::Block_dev_base< Ds_data >::finalize_request(), and L4virtio::Svr::Console::Device::notify_queue().

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◆ no_notify_host() [1/2]

bool L4virtio::Virtqueue::no_notify_host ( ) const

inline

Get the no notify flag of this queue.

Precondition: queue must be in working state.

Returns: true if the host does not want to get IRQs (currently).

Definition at line 444 of file virtqueue.

References _used.

◆ no_notify_host() [2/2]

void L4virtio::Virtqueue::no_notify_host ( bool value )

inline

Set the no-notify flag for this queue.

Precondition: Queue must be in a working state.

Definition at line 455 of file virtqueue.

References _used.

◆ num()

unsigned L4virtio::Virtqueue::num ( ) const

inline

Returns: The number of entries in the ring.

Definition at line 421 of file virtqueue.

References _idx_mask.

Referenced by avail_size(), desc_size(), L4virtio::Driver::Virtqueue::init_queue(), L4virtio::Driver::Virtqueue::init_queue(), L4virtio::Driver::Virtqueue::initialize_rings(), setup(), setup_simple(), L4virtio::Svr::Request_processor::start(), total_size(), total_size(), and used_size().

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◆ ready()

bool L4virtio::Virtqueue::ready ( ) const

inline

Test if this queue is in working state.

Returns: true when the queue is in working state, false else.

Definition at line 417 of file virtqueue.

References _desc, and L4_LIKELY.

Referenced by L4virtio::Svr::Virtqueue::disable_notify(), Virtio_net_request::drop_requests(), L4virtio::Svr::Virtqueue::enable_notify(), Virtio_net_request::get_request(), L4virtio::Svr::Console::Virtio_con::handle_control_message(), and L4virtio::Svr::Console::Virtio_con::send_control_message().

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◆ setup()

void L4virtio::Virtqueue::setup	(	unsigned	num,
		void *	desc,
		void *	avail,
		void *	used,
		L4Re::Util::Dbg	msg_dev = L4Re::Util::Dbg{2} )

inline

Enable this queue.

Parameters

num	The number of entries in the descriptor table, the available ring, and the used ring (must be a power of 2).
desc	The address of the descriptor table. (Must be Desc_align aligned and at least desc_size(num) bytes in size.)
avail	The address of the available ring. (Must be Avail_align aligned and at least avail_size(num) bytes in size.)
used	The address of the used ring. (Must be Used_align aligned and at least used_size(num) bytes in size.)
msg_dev	Debug channel for developer-related information. Verbosity of L4Re::Util::Dbg(2) by default.

Due to the data type of the descriptors, the queue can have a maximum size of 2^16.

Definition at line 359 of file virtqueue.

References num().

Referenced by L4virtio::Svr::Device_t< No_custom_data >::setup_queue().

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◆ setup_simple()

void L4virtio::Virtqueue::setup_simple	(	unsigned	num,
		void *	ring,
		L4Re::Util::Dbg	msg_dev = L4Re::Util::Dbg{2} )

inline

Enable this queue.

Parameters

num	The number of entries in the descriptor table, the available ring, and the used ring (must be a power of 2).
ring	The base address for the queue data structure. The memory block at ring must be at least total_size(num) bytes in size and have an alignment of Desc_align (desc_align()) bits.
msg_dev	Debug channel for developer-related information. Verbosity of L4Re::Util::Dbg(2) by default.

Due to the data type of the descriptors, the queue can have a maximum size of 2^16.

Definition at line 391 of file virtqueue.

References num().

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◆ total_size() [1/2]

unsigned long L4virtio::Virtqueue::total_size ( ) const

inline

Calculate the total size of this virtqueue.

Precondition: The queue has been set up.

Definition at line 322 of file virtqueue.

References _desc, _used, num(), and used_size().

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◆ total_size() [2/2]

unsigned long L4virtio::Virtqueue::total_size ( unsigned num )

inlinestatic

Calculate the total size for a virtqueue of the given dimensions.

Parameters

num	The number of entries in the descriptor table, the available ring, and the used ring (must be a power of 2).

Returns: The total size in bytes of the queue data structures.

Definition at line 253 of file virtqueue.

References avail_size(), desc_size(), l4_round_size(), num(), and used_size().

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◆ used_align()

unsigned long L4virtio::Virtqueue::used_align ( )

inlinestatic

Get the alignment in zero LSBs needed for the used ring.

Returns: The alignment in zero LSBs needed for an used ring.

Definition at line 314 of file virtqueue.

◆ used_size()

unsigned long L4virtio::Virtqueue::used_size ( unsigned num )

inlinestatic

Calculate the size of the used ring for num entries.

Parameters

num	The number of entries in the used ring.

Returns: The size in bytes needed for an used ring with num entries.

Definition at line 306 of file virtqueue.

References num().

Referenced by L4virtio::Svr::Device_t< No_custom_data >::setup_queue(), total_size(), and total_size().

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

l4/l4virtio/virtqueue

Data Structures

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Member Function Documentation

◆ avail_align()

◆ avail_size()

◆ desc_align()

◆ desc_size()

◆ disable()

◆ dump()

◆ get_avail_idx()

◆ get_tail_avail_idx()

◆ no_notify_guest()

◆ no_notify_host() [1/2]

◆ no_notify_host() [2/2]

◆ num()

◆ ready()

◆ setup()

◆ setup_simple()

◆ total_size() [1/2]

◆ total_size() [2/2]

◆ used_align()

◆ used_size()