#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_INITIALIZE, /* + base, pfnlimit, start */ LHREQ_GETDMA, /* No longer used */ LHREQ_IRQ, /* + irq */ LHREQ_BREAK, /* + on/off flag (on blocks until someone does off) */ }; /* The alignment to use between consumer and producer parts of vring. * x86 pagesize for historical reasons. */ #define LGUEST_VRING_ALIGN 4096 #endif /* _LINUX_LGUEST_LAUNCHER */