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Rusty Russell73344922007-10-25 14:12:20 +10001#ifndef _LINUX_LGUEST_LAUNCHER
2#define _LINUX_LGUEST_LAUNCHER
Rusty Russelld7e28ff2007-07-19 01:49:23 -07003/* Everything the "lguest" userspace program needs to know. */
Rusty Russellb45d8cb2007-10-22 10:56:24 +10004#include <linux/types.h>
Rusty Russelld7e28ff2007-07-19 01:49:23 -07005
Rusty Russelle2c97842007-07-26 10:41:03 -07006/*D:010
7 * Drivers
8 *
9 * The Guest needs devices to do anything useful. Since we don't let it touch
10 * real devices (think of the damage it could do!) we provide virtual devices.
11 * We could emulate a PCI bus with various devices on it, but that is a fairly
12 * complex burden for the Host and suboptimal for the Guest, so we have our own
Rusty Russelle1e72962007-10-25 15:02:50 +100013 * simple lguest bus and we use "virtio" drivers. These drivers need a set of
14 * routines from us which will actually do the virtual I/O, but they handle all
15 * the net/block/console stuff themselves. This means that if we want to add
16 * a new device, we simply need to write a new virtio driver and create support
17 * for it in the Launcher: this code won't need to change.
Rusty Russelle2c97842007-07-26 10:41:03 -070018 *
Rusty Russella6bd8e12008-03-28 11:05:53 -050019 * Virtio devices are also used by kvm, so we can simply reuse their optimized
20 * device drivers. And one day when everyone uses virtio, my plan will be
21 * complete. Bwahahahah!
22 *
Rusty Russell19f15372007-10-22 11:24:21 +100023 * Devices are described by a simplified ID, a status byte, and some "config"
24 * bytes which describe this device's configuration. This is placed by the
25 * Launcher just above the top of physical memory:
Rusty Russelle2c97842007-07-26 10:41:03 -070026 */
Rusty Russelld7e28ff2007-07-19 01:49:23 -070027struct lguest_device_desc {
Rusty Russell19f15372007-10-22 11:24:21 +100028 /* The device type: console, network, disk etc. Type 0 terminates. */
29 __u8 type;
Rusty Russella586d4f2008-02-04 23:49:56 -050030 /* The number of virtqueues (first in config array) */
31 __u8 num_vq;
32 /* The number of bytes of feature bits. Multiply by 2: one for host
Rusty Russella6bd8e12008-03-28 11:05:53 -050033 * features and one for Guest acknowledgements. */
Rusty Russella586d4f2008-02-04 23:49:56 -050034 __u8 feature_len;
35 /* The number of bytes of the config array after virtqueues. */
Rusty Russell19f15372007-10-22 11:24:21 +100036 __u8 config_len;
37 /* A status byte, written by the Guest. */
38 __u8 status;
39 __u8 config[0];
40};
Rusty Russelld7e28ff2007-07-19 01:49:23 -070041
Rusty Russell19f15372007-10-22 11:24:21 +100042/*D:135 This is how we expect the device configuration field for a virtqueue
Rusty Russella586d4f2008-02-04 23:49:56 -050043 * to be laid out in config space. */
Rusty Russell19f15372007-10-22 11:24:21 +100044struct lguest_vqconfig {
45 /* The number of entries in the virtio_ring */
46 __u16 num;
47 /* The interrupt we get when something happens. */
48 __u16 irq;
49 /* The page number of the virtio ring for this device. */
Rusty Russellb45d8cb2007-10-22 10:56:24 +100050 __u32 pfn;
Rusty Russelld7e28ff2007-07-19 01:49:23 -070051};
Rusty Russelle2c97842007-07-26 10:41:03 -070052/*:*/
Rusty Russelld7e28ff2007-07-19 01:49:23 -070053
54/* Write command first word is a request. */
55enum lguest_req
56{
Matias Zabaljauregui58a24562008-09-29 01:40:07 -030057 LHREQ_INITIALIZE, /* + base, pfnlimit, start */
Rusty Russell15045272007-10-22 11:24:10 +100058 LHREQ_GETDMA, /* No longer used */
Rusty Russelld7e28ff2007-07-19 01:49:23 -070059 LHREQ_IRQ, /* + irq */
60 LHREQ_BREAK, /* + on/off flag (on blocks until someone does off) */
61};
Rusty Russell2966af72008-12-30 09:25:58 -060062
63/* The alignment to use between consumer and producer parts of vring.
64 * x86 pagesize for historical reasons. */
65#define LGUEST_VRING_ALIGN 4096
Rusty Russell73344922007-10-25 14:12:20 +100066#endif /* _LINUX_LGUEST_LAUNCHER */