Virtual registers (guest_shm.h)

The guest_shm.h public header file includes definitions for guests using the shmem vdev.

GUEST_SHM_*

Synopsis:

#define GUEST_SHM_MAX_CLIENTS	16
#define GUEST_SHM_MAX_NAME	32
#define GUEST_SHM_SIGNATURE 0x4d534732474d5651

Data:

The GUEST_SHM_* constants include the following:

GUEST_SHM_MAX_CLIENTS
Maximum number of clients allowed to connect to a shared memory region (16)
GUEST_SHM_MAX_NAME
Maximum length allowed for a region name, in bytes (32)
GUEST_SHM_SIGNATURE
Signature value to verify that the vdev is present (0x4d534732474d5651)

guest_shm_control

Register layout for a region control page

Synopsis:

struct guest_shm_control {
  uint32_t    status;
  uint32_t    idx;
  uint32_t    notify;
  uint32_t    detach;
};

Data:

The members of guest_shm_control include:

status
Read only. Lower 16 bits: pending notification bitset; upper 16 bits: current active clients (see guest_shm_status below).
idx
Read only. Connection index for this client.
notify
Write a bitset here to indicate which clients to notify.
detach
Write here to detach your client from the shared memory region.

guest_shm_factory

Register layout for shared memory factory page registers

Synopsis:

struct guest_shm_factory {
  uint64_t    signature;
  uint64_t    shmem;
  uint32_t    vector;
  uint32_t    status;
  uint32_t    size;
  char        name[GUEST_SHM_MAX_NAME];
  uint32_t    find;
};

Data:

The members of guest_shm_factory include:

signature
Read only. Is GUEST_SHM_SIGNATURE (see GUEST_SHM_* above).
shmem
Read only. The location of the shared memory in guest-physical memory.
vector
Read only. The interrupt number for this shared memory region.
status
Read only. The status of the last creation attempt (see guest_shm_status below).
size
The size of the requested named shared memory region, in multiples of 4 KB pages. A write with this value creates a shared memory region, if the region with the specified name and size doesn't already exist.
name
The name of the shared memory region.
find
Whether to find an existing shared memory connection.

guest_shm_status

Status of last request to create a named shared memory region

Synopsis:

enum guest_shm_status {
  GSS_OK,
  GSS_UNKNOWN_FAILURE,
  GSS_NOMEM,
  GSS_CLIENT_MAX,
  GSS_ILLEGAL_NAME,
  GSS_NO_PERMISSION,
  GSS_DOES_NOT_EXIST,
};

Data:

The guest_shm_status enumeration defines these values:

GSS_OK
The region was successfully created.
GSS_UNKNOWN_FAILURE
The region creation failed due to an unknown reason.
GSS_NOMEM
There was insufficient memory to create the region.
GSS_CLIENT_MAX
The region can't be connected to because it is already being used by the maximum permitted number of guests.
GSS_ILLEGAL_NAME
The region creation failed because the specified region name is illegal.
GSS_NO_PERMISSION
The region creation failed because the process attempting to create it has insufficient permissions.
GSS_DOES_NOT_EXIST
An attempt to find a named shared memory region failed.

PCI_VID_* and PCI_DID_*

Vendor IDs and Device IDs

Synopsis:

#define PCI_VID_BlackBerry_QNX   0x1C05
#define PCI_DID_QNX_GUEST_SHM    0x0001
Page updated: