qemu/hw/virtio-serial.h
Amit Shah 9ed7b059ef virtio-serial: Implement flow control for individual ports
Individual ports can now signal to the virtio-serial core to stop
sending data if the ports cannot immediately handle new data.  When a
port later unthrottles, any data queued up in the virtqueue are sent to
the port.

Disable throttling once a port is closed (and we discard all the
unconsumed buffers in the vq).

The guest kernel can reclaim the buffers when it receives the port close
event or when a port is being removed. Ensure we free up the buffers
before we send out any events to the guest.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-04-28 08:58:22 -05:00

186 lines
5.1 KiB
C

/*
* Virtio Serial / Console Support
*
* Copyright IBM, Corp. 2008
* Copyright Red Hat, Inc. 2009, 2010
*
* Authors:
* Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
* Amit Shah <amit.shah@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#ifndef _QEMU_VIRTIO_SERIAL_H
#define _QEMU_VIRTIO_SERIAL_H
#include <stdbool.h>
#include "qdev.h"
#include "virtio.h"
/* == Interface shared between the guest kernel and qemu == */
/* The Virtio ID for virtio console / serial ports */
#define VIRTIO_ID_CONSOLE 3
/* Features supported */
#define VIRTIO_CONSOLE_F_MULTIPORT 1
#define VIRTIO_CONSOLE_BAD_ID (~(uint32_t)0)
struct virtio_console_config {
/*
* These two fields are used by VIRTIO_CONSOLE_F_SIZE which
* isn't implemented here yet
*/
uint16_t cols;
uint16_t rows;
uint32_t max_nr_ports;
} __attribute__((packed));
struct virtio_console_control {
uint32_t id; /* Port number */
uint16_t event; /* The kind of control event (see below) */
uint16_t value; /* Extra information for the key */
};
/* Some events for the internal messages (control packets) */
#define VIRTIO_CONSOLE_DEVICE_READY 0
#define VIRTIO_CONSOLE_PORT_ADD 1
#define VIRTIO_CONSOLE_PORT_REMOVE 2
#define VIRTIO_CONSOLE_PORT_READY 3
#define VIRTIO_CONSOLE_CONSOLE_PORT 4
#define VIRTIO_CONSOLE_RESIZE 5
#define VIRTIO_CONSOLE_PORT_OPEN 6
#define VIRTIO_CONSOLE_PORT_NAME 7
/* == In-qemu interface == */
typedef struct VirtIOSerial VirtIOSerial;
typedef struct VirtIOSerialBus VirtIOSerialBus;
typedef struct VirtIOSerialPort VirtIOSerialPort;
typedef struct VirtIOSerialPortInfo VirtIOSerialPortInfo;
typedef struct VirtIOSerialDevice {
DeviceState qdev;
VirtIOSerialPortInfo *info;
} VirtIOSerialDevice;
/*
* This is the state that's shared between all the ports. Some of the
* state is configurable via command-line options. Some of it can be
* set by individual devices in their initfn routines. Some of the
* state is set by the generic qdev device init routine.
*/
struct VirtIOSerialPort {
DeviceState dev;
VirtIOSerialPortInfo *info;
QTAILQ_ENTRY(VirtIOSerialPort) next;
/*
* This field gives us the virtio device as well as the qdev bus
* that we are associated with
*/
VirtIOSerial *vser;
VirtQueue *ivq, *ovq;
/*
* This name is sent to the guest and exported via sysfs.
* The guest could create symlinks based on this information.
* The name is in the reverse fqdn format, like org.qemu.console.0
*/
char *name;
/*
* This id helps identify ports between the guest and the host.
* The guest sends a "header" with this id with each data packet
* that it sends and the host can then find out which associated
* device to send out this data to
*/
uint32_t id;
/* Identify if this is a port that binds with hvc in the guest */
uint8_t is_console;
/* Is the corresponding guest device open? */
bool guest_connected;
/* Is this device open for IO on the host? */
bool host_connected;
/* Do apps not want to receive data? */
bool throttled;
};
struct VirtIOSerialPortInfo {
DeviceInfo qdev;
/*
* The per-port (or per-app) init function that's called when a
* new device is found on the bus.
*/
int (*init)(VirtIOSerialDevice *dev);
/*
* Per-port exit function that's called when a port gets
* hot-unplugged or removed.
*/
int (*exit)(VirtIOSerialDevice *dev);
/* Callbacks for guest events */
/* Guest opened device. */
void (*guest_open)(VirtIOSerialPort *port);
/* Guest closed device. */
void (*guest_close)(VirtIOSerialPort *port);
/* Guest is now ready to accept data (virtqueues set up). */
void (*guest_ready)(VirtIOSerialPort *port);
/*
* Guest wrote some data to the port. This data is handed over to
* the app via this callback. The app is supposed to consume all
* the data that is presented to it.
*/
void (*have_data)(VirtIOSerialPort *port, const uint8_t *buf, size_t len);
};
/* Interface to the virtio-serial bus */
/*
* Individual ports/apps should call this function to register the port
* with the virtio-serial bus
*/
void virtio_serial_port_qdev_register(VirtIOSerialPortInfo *info);
/*
* Open a connection to the port
* Returns 0 on success (always).
*/
int virtio_serial_open(VirtIOSerialPort *port);
/*
* Close the connection to the port
* Returns 0 on success (always).
*/
int virtio_serial_close(VirtIOSerialPort *port);
/*
* Send data to Guest
*/
ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
size_t size);
/*
* Query whether a guest is ready to receive data.
*/
size_t virtio_serial_guest_ready(VirtIOSerialPort *port);
/*
* Flow control: Ports can signal to the virtio-serial core to stop
* sending data or re-start sending data, depending on the 'throttle'
* value here.
*/
void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle);
#endif