#ifndef _LINUX_LGUEST_LAUNCHER

#define _LINUX_LGUEST_LAUNCHER

/* Everything the "lguest" userspace program needs to know. */

#include <linux/types.h>

/*D:010

 * Drivers

 *

 * The Guest needs devices to do anything useful.  Since we don't let it touch

 * real devices (think of the damage it could do!) we provide virtual devices.

 * We could emulate a PCI bus with various devices on it, but that is a fairly

 * complex burden for the Host and suboptimal for the Guest, so we have our own

 * simple lguest bus and we use "virtio" drivers.  These drivers need a set of

 * routines from us which will actually do the virtual I/O, but they handle all

 * the net/block/console stuff themselves.  This means that if we want to add

 * a new device, we simply need to write a new virtio driver and create support

 * for it in the Launcher: this code won't need to change.

 *

 * Virtio devices are also used by kvm, so we can simply reuse their optimized

 * device drivers.  And one day when everyone uses virtio, my plan will be

 * complete.  Bwahahahah!

 *

 * Devices are described by a simplified ID, a status byte, and some "config"

 * bytes which describe this device's configuration.  This is placed by the

 * Launcher just above the top of physical memory:

 */

struct lguest_device_desc {

	/* The device type: console, network, disk etc.  Type 0 terminates. */

	__u8 type;

	/* The number of virtqueues (first in config array) */

	__u8 num_vq;

	/* The number of bytes of feature bits.  Multiply by 2: one for host

	 * features and one for Guest acknowledgements. */

	__u8 feature_len;

	/* The number of bytes of the config array after virtqueues. */

	__u8 config_len;

	/* A status byte, written by the Guest. */

	__u8 status;

	__u8 config[0];

};

/*D:135 This is how we expect the device configuration field for a virtqueue

 * to be laid out in config space. */

struct lguest_vqconfig {

	/* The number of entries in the virtio_ring */

	__u16 num;

	/* The interrupt we get when something happens. */

	__u16 irq;

	/* The page number of the virtio ring for this device. */

	__u32 pfn;

};

/*:*/

/* Write command first word is a request. */

enum lguest_req

{

	LHREQ_GETDMA, /* No longer used */

	LHREQ_IRQ, /* + irq */

	LHREQ_BREAK, /* + on/off flag (on blocks until someone does off) */

};

#endif /* _LINUX_LGUEST_LAUNCHER */