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#ifndef _ASM_LGUEST_USER
#define _ASM_LGUEST_USER
/* Everything the "lguest" userspace program needs to know. */
#include <linux/types.h>
/* They can register up to 32 arrays of lguest_dma. */
#define LGUEST_MAX_DMA 32
/* At most we can dma 16 lguest_dma in one op. */
#define LGUEST_MAX_DMA_SECTIONS 16
/* How many devices? Assume each one wants up to two dma arrays per device. */
#define LGUEST_MAX_DEVICES (LGUEST_MAX_DMA/2)
/*D:200
* Lguest I/O
*
* The lguest I/O mechanism is the only way Guests can talk to devices. There
* are two hypercalls involved: SEND_DMA for output and BIND_DMA for input. In
* each case, "struct lguest_dma" describes the buffer: this contains 16
* addr/len pairs, and if there are fewer buffer elements the len array is
* terminated with a 0.
*
* I/O is organized by keys: BIND_DMA attaches buffers to a particular key, and
* SEND_DMA transfers to buffers bound to particular key. By convention, keys
* correspond to a physical address within the device's page. This means that
* devices will never accidentally end up with the same keys, and allows the
* Host use The Futex Trick (as we'll see later in our journey).
*
* SEND_DMA simply indicates a key to send to, and the physical address of the
* "struct lguest_dma" to send. The Host will write the number of bytes
* transferred into the "struct lguest_dma"'s used_len member.
*
* BIND_DMA indicates a key to bind to, a pointer to an array of "struct
* lguest_dma"s ready for receiving, the size of that array, and an interrupt
* to trigger when data is received. The Host will only allow transfers into
* buffers with a used_len of zero: it then sets used_len to the number of
* bytes transferred and triggers the interrupt for the Guest to process the
* new input. */
struct lguest_dma
{
/* 0 if free to be used, filled by the Host. */
__u32 used_len;
__u16 len[LGUEST_MAX_DMA_SECTIONS];
unsigned long addr[LGUEST_MAX_DMA_SECTIONS];
};
/*:*/
/* Where the Host expects the Guest to SEND_DMA console output to. */
#define LGUEST_CONSOLE_DMA_KEY 0
/*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
* "lguest" bus and simple drivers.
*
* Devices are described by an array of LGUEST_MAX_DEVICES of these structs,
* placed by the Launcher just above the top of physical memory:
*/
struct lguest_device_desc {
/* The device type: console, network, disk etc. */
__u16 type;
#define LGUEST_DEVICE_T_CONSOLE 1
#define LGUEST_DEVICE_T_NET 2
#define LGUEST_DEVICE_T_BLOCK 3
/* The specific features of this device: these depends on device type
* except for LGUEST_DEVICE_F_RANDOMNESS. */
__u16 features;
#define LGUEST_NET_F_NOCSUM 0x4000 /* Don't bother checksumming */
#define LGUEST_DEVICE_F_RANDOMNESS 0x8000 /* IRQ is fairly random */
/* This is how the Guest reports status of the device: the Host can set
* LGUEST_DEVICE_S_REMOVED to indicate removal, but the rest are only
* ever manipulated by the Guest, and only ever set. */
__u16 status;
/* 256 and above are device specific. */
#define LGUEST_DEVICE_S_ACKNOWLEDGE 1 /* We have seen device. */
#define LGUEST_DEVICE_S_DRIVER 2 /* We have found a driver */
#define LGUEST_DEVICE_S_DRIVER_OK 4 /* Driver says OK! */
#define LGUEST_DEVICE_S_REMOVED 8 /* Device has gone away. */
#define LGUEST_DEVICE_S_REMOVED_ACK 16 /* Driver has been told. */
#define LGUEST_DEVICE_S_FAILED 128 /* Something actually failed */
/* Each device exists somewhere in Guest physical memory, over some
* number of pages. */
__u16 num_pages;
__u32 pfn;
};
/*:*/
/* Write command first word is a request. */
enum lguest_req
{
LHREQ_INITIALIZE, /* + pfnlimit, pgdir, start, pageoffset */
LHREQ_GETDMA, /* + addr (returns &lguest_dma, irq in ->used_len) */
LHREQ_IRQ, /* + irq */
LHREQ_BREAK, /* + on/off flag (on blocks until someone does off) */
};
#endif /* _ASM_LGUEST_USER */
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