L4Re - L4 Runtime Environment
L4 VIRTIO Transport Layer

L4 specific VIRTIO Transport layer. More...

+ Collaboration diagram for L4 VIRTIO Transport Layer:

Namespaces

 L4virtio
 L4-VIRTIO Transport C++ API.
 

Data Structures

struct  l4virtio_config_hdr_t
 L4-VIRTIO config header, provided in shared data space. More...
 
struct  l4virtio_config_queue_t
 Queue configuration entry. More...
 

Typedefs

typedef struct l4virtio_config_hdr_t l4virtio_config_hdr_t
 L4-VIRTIO config header, provided in shared data space.
 
typedef struct l4virtio_config_queue_t l4virtio_config_queue_t
 Queue configuration entry. More...
 

Enumerations

enum  L4_virtio_protocol
 L4-VIRTIO protocol number.
 
enum  L4_virtio_opcodes { L4VIRTIO_OP_SET_STATUS = 0, L4VIRTIO_OP_CONFIG_QUEUE, L4VIRTIO_OP_REGISTER_IFACE, L4VIRTIO_OP_REGISTER_DS }
 L4-VIRTIO opcodes. More...
 
enum  L4virtio_device_ids {
  L4VIRTIO_ID_NET = 1, L4VIRTIO_ID_BLOCK = 2, L4VIRTIO_ID_CONSOLE = 3, L4VIRTIO_ID_RNG = 4,
  L4VIRTIO_ID_BALLOON = 5, L4VIRTIO_ID_RPMSG = 7, L4VIRTIO_ID_SCSI = 8, L4VIRTIO_ID_9P = 9,
  L4VIRTIO_ID_RPROC_SERIAL = 11, L4VIRTIO_ID_CAIF = 12, L4VIRTIO_ID_GPU = 16, L4VIRTIO_ID_INPUT = 18,
  L4VIRTIO_ID_VSOCK = 19, L4VIRTIO_ID_CRYPTO = 20, L4VIRTIO_ID_SOCK = 0x9999
}
 Virtio device IDs as reported in the driver's config space. More...
 
enum  L4virtio_device_status {
  L4VIRTIO_STATUS_ACKNOWLEDGE = 1, L4VIRTIO_STATUS_DRIVER = 2, L4VIRTIO_STATUS_DRIVER_OK = 4, L4VIRTIO_STATUS_FEATURES_OK = 8,
  L4VIRTIO_STATUS_FAILED = 0x80
}
 Virtio device status bits. More...
 
enum  L4virtio_feature_bits { L4VIRTIO_FEATURE_VERSION_1 = 32, L4VIRTIO_FEATURE_CMD_CONFIG = 224 }
 L4virtio-specific feature bits. More...
 
enum  L4_virtio_irq_status { L4VIRTIO_IRQ_STATUS_VRING = 1, L4VIRTIO_IRQ_STATUS_CONFIG = 2 }
 VIRTIO IRQ status codes (l4virtio_config_hdr_t::irq_status). More...
 
enum  L4_virtio_cmd { L4VIRTIO_CMD_NONE = 0x00000000, L4VIRTIO_CMD_SET_STATUS = 0x01000000, L4VIRTIO_CMD_CFG_QUEUE = 0x02000000, L4VIRTIO_CMD_MASK = 0xff000000 }
 Virtio commands for device configuration. More...
 

Functions

l4virtio_config_queue_tl4virtio_config_queues (l4virtio_config_hdr_t const *cfg)
 Get the pointer to the first queue config. More...
 
void * l4virtio_device_config (l4virtio_config_hdr_t const *cfg)
 Get the pointer to the device configuration. More...
 
void l4virtio_set_feature (l4_uint32_t *feature_map, unsigned feat)
 Set the given feature bit in a feature map.
 
void l4virtio_clear_feature (l4_uint32_t *feature_map, unsigned feat)
 Clear the given feature bit in a feature map.
 
unsigned l4virtio_get_feature (l4_uint32_t *feature_map, unsigned feat)
 Check if the given bit in a feature map is set.
 
int l4virtio_set_status (l4_cap_idx_t cap, unsigned status) L4_NOTHROW
 Write the VIRTIO status register. More...
 
int l4virtio_config_queue (l4_cap_idx_t cap, unsigned queue) L4_NOTHROW
 Trigger queue configuration of the given queue. More...
 
int l4virtio_register_ds (l4_cap_idx_t cap, l4_cap_idx_t ds_cap, l4_uint64_t base, l4_umword_t offset, l4_umword_t size) L4_NOTHROW
 Register a shared data space with VIRTIO host. More...
 
int l4virtio_register_iface (l4_cap_idx_t cap, l4_cap_idx_t guest_irq, l4_cap_idx_t host_irq, l4_cap_idx_t config_ds) L4_NOTHROW
 Register client to the given L4-VIRTIO host. More...
 

Detailed Description

L4 specific VIRTIO Transport layer.

The L4 specific VIRTIO Transport layer is based on L4Re::Dataspace as shared memory and L4::Irq for signaling. The VIRTIO configuration space is mostly based on a shared memory implementation too and accompanied by two IPC functions to synchronize the configuration between device and driver.

Typedef Documentation

◆ l4virtio_config_queue_t

Queue configuration entry.

An array of such entries is available at the l4virtio_config_hdr_t::queues_offset in the config data space.

Consistency rules for the queue config are:

  • A driver might read num_max at any time.
  • A driver must write to num, desc_addr, avail_addr, and used_addr only when ready is zero (0). Values in these fields are validated and used by the device only after successfully setting ready to one (1), either by the IPC or by L4VIRTIO_CMD_CFG_QUEUE.
  • The value of device_notify_index is valid only when ready is one.
  • The driver might write to device_notify_index at any time, however the change is guaranteed to take effect after a successful L4VIRTIO_CMD_CFG_QUEUE or after a config_queue IPC. Note, the change might also have immediate effect, depending on the device implementation.

Enumeration Type Documentation

◆ L4_virtio_cmd

Virtio commands for device configuration.

Enumerator
L4VIRTIO_CMD_NONE 

No command pending.

L4VIRTIO_CMD_SET_STATUS 

Set the status register.

L4VIRTIO_CMD_CFG_QUEUE 

Configure a queue.

L4VIRTIO_CMD_MASK 

Mask to get command bits.

Definition at line 116 of file virtio.h.

◆ L4_virtio_irq_status

VIRTIO IRQ status codes (l4virtio_config_hdr_t::irq_status).

Note
l4virtio_config_hdr_t::irq_status is currently unused.
Enumerator
L4VIRTIO_IRQ_STATUS_VRING 

VRING IRQ pending flag.

L4VIRTIO_IRQ_STATUS_CONFIG 

CONFIG IRQ pending flag.

Definition at line 107 of file virtio.h.

◆ L4_virtio_opcodes

L4-VIRTIO opcodes.

Enumerator
L4VIRTIO_OP_SET_STATUS 

Set status register in device config.

L4VIRTIO_OP_CONFIG_QUEUE 

Set queue config in device config.

L4VIRTIO_OP_REGISTER_IFACE 

Register a transport driver to the device.

L4VIRTIO_OP_REGISTER_DS 

Register a data space as transport memory.

Definition at line 55 of file virtio.h.

◆ L4virtio_device_ids

Virtio device IDs as reported in the driver's config space.

Enumerator
L4VIRTIO_ID_NET 

Virtual ethernet card.

L4VIRTIO_ID_BLOCK 

General block device.

L4VIRTIO_ID_CONSOLE 

Simple device for data IO via ports.

L4VIRTIO_ID_RNG 

Entropy source.

L4VIRTIO_ID_BALLOON 

Memory balooning device.

L4VIRTIO_ID_RPMSG 

Device using rpmsg protocol.

L4VIRTIO_ID_SCSI 

SCSI host device.

L4VIRTIO_ID_9P 

Device using 9P transport protocol.

L4VIRTIO_ID_RPROC_SERIAL 

Rproc serial device.

L4VIRTIO_ID_CAIF 

Device using CAIF network protocol.

L4VIRTIO_ID_GPU 

GPU.

L4VIRTIO_ID_INPUT 

Input.

L4VIRTIO_ID_VSOCK 

Vsock transport.

L4VIRTIO_ID_CRYPTO 

Crypto.

L4VIRTIO_ID_SOCK 

Inofficial socket device.

Definition at line 64 of file virtio.h.

◆ L4virtio_device_status

Virtio device status bits.

Enumerator
L4VIRTIO_STATUS_ACKNOWLEDGE 

Guest OS has found device.

L4VIRTIO_STATUS_DRIVER 

Guest OS knows how to drive device.

L4VIRTIO_STATUS_DRIVER_OK 

Driver is set up.

L4VIRTIO_STATUS_FEATURES_OK 

Driver has acknowledged feature set.

L4VIRTIO_STATUS_FAILED 

Fatal error in driver or device.

Definition at line 85 of file virtio.h.

◆ L4virtio_feature_bits

L4virtio-specific feature bits.

Enumerator
L4VIRTIO_FEATURE_VERSION_1 

Virtio protocol version 1 supported. Must be 1 for L4virtio.

L4VIRTIO_FEATURE_CMD_CONFIG 

Status and queue config are set via cmd field instead of via IPC.

Definition at line 95 of file virtio.h.

Function Documentation

◆ l4virtio_config_queue()

int l4virtio_config_queue ( l4_cap_idx_t  cap,
unsigned  queue 
)

Trigger queue configuration of the given queue.

Usually all queues are configured when the status is written to running. However, in some cases queues shall be disabled or enabled dynamically, in this case this function triggers a reconfiguration from the shared memory register of the queue config.

Parameters
capCapability to the VIRTIO host.
queueQueue index for the queue to be configured.
Return values
0on success.
-L4_EIOThe queue's status is invalid.
-L4_ERANGEThe queue index exceeds the number of queues.
-L4_EINVALOtherwise.

Referenced by l4virtio_get_feature().

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◆ l4virtio_config_queues()

l4virtio_config_queue_t* l4virtio_config_queues ( l4virtio_config_hdr_t const *  cfg)
inline

Get the pointer to the first queue config.

Parameters
cfgPointer to the config header.
Returns
pointer to queue config of queue 0.

Definition at line 237 of file virtio.h.

◆ l4virtio_device_config()

void* l4virtio_device_config ( l4virtio_config_hdr_t const *  cfg)
inline

Get the pointer to the device configuration.

Parameters
cfgPointer to the config header.
Returns
pointer to device configuration structure.

Definition at line 248 of file virtio.h.

◆ l4virtio_register_ds()

int l4virtio_register_ds ( l4_cap_idx_t  cap,
l4_cap_idx_t  ds_cap,
l4_uint64_t  base,
l4_umword_t  offset,
l4_umword_t  size 
)

Register a shared data space with VIRTIO host.

Parameters
capCapability to the VIRTIO host
ds_capData-space capability to register. The lower 8 bits determine the rights mask with which the guest's rights are masked during the registration of the dataspace at the VIRTIO host.
baseVIRTIO guest physical start address of shared memory region
offsetOffset within the data space that is attached to the given base in the guest physical memory.
sizeSize of the memory region in the guest
Returns
0 on success, < 0 on error

Referenced by l4virtio_get_feature().

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◆ l4virtio_register_iface()

int l4virtio_register_iface ( l4_cap_idx_t  cap,
l4_cap_idx_t  guest_irq,
l4_cap_idx_t  host_irq,
l4_cap_idx_t  config_ds 
)

Register client to the given L4-VIRTIO host.

Parameters
capCapability to the L4-VIRTIO host
guest_irqIRQ capability for valid IRQ object for host-to-guest notifications
host_irqCapability selector for receiving the guest-to-host notifications IRQ capability.
config_dsCapability for receiving the data-space capability for the shared L4-VIRTIO config data space.
Return values
0on success.
-L4_EINVALThe host did not receive the guest_irq cap.

Referenced by l4virtio_get_feature().

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◆ l4virtio_set_status()

int l4virtio_set_status ( l4_cap_idx_t  cap,
unsigned  status 
)

Write the VIRTIO status register.

Note
All other registers are accessed via shared memory.
Parameters
capCapability to the VIRTIO host
statusStatus word to write to the VIRTIO status.
Returns
0 on success, <0 on error.

Referenced by l4virtio_get_feature().

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