a586d4f601
Previously we used a type/len pair within the config space, but this seems overkill. We now simply define a structure which represents the layout in the config space: the config space can now only be extended at the end. The main driver-visible changes: 1) We indicate what fields are present with an explicit feature bit. 2) Virtqueues are explicitly numbered, and not in the config space. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
59 lines
2.1 KiB
C
59 lines
2.1 KiB
C
#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.
|
|
*
|
|
* 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_INITIALIZE, /* + base, pfnlimit, pgdir, start */
|
|
LHREQ_GETDMA, /* No longer used */
|
|
LHREQ_IRQ, /* + irq */
|
|
LHREQ_BREAK, /* + on/off flag (on blocks until someone does off) */
|
|
};
|
|
#endif /* _LINUX_LGUEST_LAUNCHER */
|