L4virtio::Svr::Request_processor Class Reference

Encapsulate the state for processing a VIRTIO request. More...

#include <virtio>

Collaboration diagram for L4virtio::Svr::Request_processor:

Public Member Functions
template<typename DESC_MAN , typename ... ARGS>
void	start (DESC_MAN *dm, Virtqueue *ring, Virtqueue::Head_desc const &request, ARGS... args)
	Start processing a new request.
template<typename DESC_MAN , typename ... ARGS>
Virtqueue::Request const &	start (DESC_MAN *dm, Virtqueue::Request const &request, ARGS... args)
	Start processing a new request.
Virtqueue::Desc::Flags	current_flags () const
	Get the flags of the currently processed descriptor.
bool	has_more () const
	Are there more chained descriptors?
template<typename DESC_MAN , typename ... ARGS>
bool	next (DESC_MAN *dm, ARGS... args)
	Switch to the next descriptor in a descriptor chain.

Detailed Description

Encapsulate the state for processing a VIRTIO request.

A VIRTIO request is a possibly chained list of descriptors retrieved from the available ring of a virtqueue, using Virtqueue::next_avail().

The descriptor processing depends on helper (DESC_MAN) for interpreting the descriptors in the context of the device implementation.

DESC_MAN has to provide the functionality to safely dereference a descriptor from a descriptor list.

The following methods must be provided by DESC_MAN:

• DESC_MAN::load_desc(Virtqueue::Desc const &desc,
                      Request_processor const *proc,
                      Virtqueue::Desc const **table) 

  This function is used to dereference desc as an indirect descriptor table, and must return a pointer to an indirect descriptor table.

• DESC_MAN::load_desc(Virtqueue::Desc const &desc,
                      Request_processor const *proc, ...) 

  This function is used to dereference a descriptor as a normal data buffer, and '...' are the arguments that are passed to start() and next().

Definition at line 399 of file virtio.

Member Function Documentation

current_flags()

Virtqueue::Desc::Flags L4virtio::Svr::Request_processor::current_flags ( ) const

inline

Get the flags of the currently processed descriptor.

Returns

The flags of the currently processed descriptor.

Definition at line 469 of file virtio.

References L4virtio::Virtqueue::Desc::flags.

has_more()

bool L4virtio::Svr::Request_processor::has_more ( ) const

inline

Are there more chained descriptors?

Returns

true if there are more chained descriptors in the current request.

Definition at line 476 of file virtio.

References L4virtio::Virtqueue::Desc::flags, and L4virtio::Virtqueue::Desc::Flags::next().

Referenced by L4virtio::Svr::Block_request< Ds_data >::data_size(), L4virtio::Svr::Block_request< Ds_data >::has_more(), and L4virtio::Svr::Block_request< Ds_data >::next_block().

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next()

template<typename DESC_MAN , typename ... ARGS>

bool L4virtio::Svr::Request_processor::next ( DESC_MAN *  dm, ARGS...  args  )

inline

Switch to the next descriptor in a descriptor chain.

Template Parameters

DESC_MAN

Type of descriptor manager (implicit).

Parameters

dm	Descriptor manager that is used to translate VIRTIO descriptor addresses.
args	Extra arguments passed to dm->load_desc()

Return values

true	A next descriptor is available.
false	No descriptor available.

Exceptions

Bad_descriptor

The next index of this descriptor is invalid.

Definition at line 493 of file virtio.

References cxx::access_once(), L4virtio::Svr::Bad_descriptor::Bad_flags, L4virtio::Svr::Bad_descriptor::Bad_next, L4virtio::Virtqueue::Desc::flags, L4virtio::Virtqueue::Desc::Flags::indirect(), L4_UNLIKELY, L4virtio::Virtqueue::Desc::Flags::next(), and L4virtio::Virtqueue::Desc::next.

Referenced by L4virtio::Svr::Block_request< Ds_data >::data_size(), L4virtio::Svr::Block_request< Ds_data >::has_more(), and L4virtio::Svr::Block_request< Ds_data >::next_block().

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start() [1/2]

template<typename DESC_MAN , typename ... ARGS>

void L4virtio::Svr::Request_processor::start ( DESC_MAN *  dm, Virtqueue *  ring, Virtqueue::Head_desc const &  request, ARGS...  args  )

inline

Start processing a new request.

Template Parameters

DESC_MAN

Type of descriptor manager (implicit).

Parameters

dm	Descriptor manager that is used to translate VIRTIO descriptor addresses.
ring	VIRTIO ring of the request.
request	VIRTIO request from Virtqueue::next_avail()
args	Extra arguments passed to dm->load_desc()

Precondition

The given request must be valid.

Exceptions

Bad_descriptor

The descriptor has an invalid size or load_desc() has thrown an exception by itself.

Definition at line 428 of file virtio.

References cxx::access_once(), L4virtio::Svr::Bad_descriptor::Bad_size, L4virtio::Svr::Virtqueue::Head_desc::desc(), L4virtio::Svr::Virtqueue::desc(), L4virtio::Virtqueue::Desc::flags, L4virtio::Virtqueue::Desc::Flags::indirect(), L4_UNLIKELY, L4virtio::Virtqueue::Desc::len, and L4virtio::Virtqueue::num().

Referenced by L4virtio::Svr::Block_request< Ds_data >::data_size(), and start().

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start() [2/2]

template<typename DESC_MAN , typename ... ARGS>

Virtqueue::Request const & L4virtio::Svr::Request_processor::start ( DESC_MAN *  dm, Virtqueue::Request const &  request, ARGS...  args  )

inline

Start processing a new request.

Template Parameters

DESC_MAN

Type of descriptor manager (implicit).

Parameters

dm	Descriptor manager that is used to translate VIRTIO descriptor addresses.
request	VIRTIO request from Virtqueue::next_avail()
args	Extra arguments passed to dm->load_desc()

Precondition

The given request must be valid.

Definition at line 459 of file virtio.

References start().

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

• l4/l4virtio/server/virtio