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1 | #ifndef _LINUX_LGUEST_LAUNCHER |
2 | #define _LINUX_LGUEST_LAUNCHER | |
d7e28ffe | 3 | /* Everything the "lguest" userspace program needs to know. */ |
b45d8cb0 | 4 | #include <linux/types.h> |
d7e28ffe | 5 | |
e2c97843 RR |
6 | /*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 | |
e1e72965 RR |
13 | * 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. | |
e2c97843 | 18 | * |
a6bd8e13 RR |
19 | * 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 | * | |
19f1537b RR |
23 | * 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: | |
e2c97843 | 26 | */ |
d7e28ffe | 27 | struct lguest_device_desc { |
19f1537b RR |
28 | /* The device type: console, network, disk etc. Type 0 terminates. */ |
29 | __u8 type; | |
a586d4f6 RR |
30 | /* 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 | |
a6bd8e13 | 33 | * features and one for Guest acknowledgements. */ |
a586d4f6 RR |
34 | __u8 feature_len; |
35 | /* The number of bytes of the config array after virtqueues. */ | |
19f1537b RR |
36 | __u8 config_len; |
37 | /* A status byte, written by the Guest. */ | |
38 | __u8 status; | |
39 | __u8 config[0]; | |
40 | }; | |
d7e28ffe | 41 | |
19f1537b | 42 | /*D:135 This is how we expect the device configuration field for a virtqueue |
a586d4f6 | 43 | * to be laid out in config space. */ |
19f1537b RR |
44 | struct 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. */ | |
b45d8cb0 | 50 | __u32 pfn; |
d7e28ffe | 51 | }; |
e2c97843 | 52 | /*:*/ |
d7e28ffe RR |
53 | |
54 | /* Write command first word is a request. */ | |
55 | enum lguest_req | |
56 | { | |
58a24566 | 57 | LHREQ_INITIALIZE, /* + base, pfnlimit, start */ |
15045275 | 58 | LHREQ_GETDMA, /* No longer used */ |
d7e28ffe RR |
59 | LHREQ_IRQ, /* + irq */ |
60 | LHREQ_BREAK, /* + on/off flag (on blocks until someone does off) */ | |
61 | }; | |
2966af73 RR |
62 | |
63 | /* The alignment to use between consumer and producer parts of vring. | |
64 | * x86 pagesize for historical reasons. */ | |
65 | #define LGUEST_VRING_ALIGN 4096 | |
7334492b | 66 | #endif /* _LINUX_LGUEST_LAUNCHER */ |