1#ifndef _LINUX_LGUEST_LAUNCHER 2#define _LINUX_LGUEST_LAUNCHER 3/* Everything the "lguest" userspace program needs to know. */ 4#include <linux/types.h> 5 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 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. 18 * 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 * 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: 26 */ 27struct lguest_device_desc { 28 /* The device type: console, network, disk etc. Type 0 terminates. */ 29 __u8 type; 30 /* The number of virtqueues (first in config array) */ 31 __u8 num_vq; 32 /* 33 * The number of bytes of feature bits. Multiply by 2: one for host 34 * features and one for Guest acknowledgements. 35 */ 36 __u8 feature_len; 37 /* The number of bytes of the config array after virtqueues. */ 38 __u8 config_len; 39 /* A status byte, written by the Guest. */ 40 __u8 status; 41 __u8 config[0]; 42}; 43 44/*D:135 45 * This is how we expect the device configuration field for a virtqueue 46 * to be laid out in config space. 47 */ 48struct lguest_vqconfig { 49 /* The number of entries in the virtio_ring */ 50 __u16 num; 51 /* The interrupt we get when something happens. */ 52 __u16 irq; 53 /* The page number of the virtio ring for this device. */ 54 __u32 pfn; 55}; 56/*:*/ 57 58/* Write command first word is a request. */ 59enum lguest_req 60{ 61 LHREQ_INITIALIZE, /* + base, pfnlimit, start */ 62 LHREQ_GETDMA, /* No longer used */ 63 LHREQ_IRQ, /* + irq */ 64 LHREQ_BREAK, /* No longer used */ 65 LHREQ_EVENTFD, /* + address, fd. */ 66}; 67 68/* 69 * The alignment to use between consumer and producer parts of vring. 70 * x86 pagesize for historical reasons. 71 */ 72#define LGUEST_VRING_ALIGN 4096 73#endif /* _LINUX_LGUEST_LAUNCHER */ 74