drivers/lguest/lg.h

#ifndef _LGUEST_H
#define _LGUEST_H

#include <asm/desc.h>

#define GDT_ENTRY_LGUEST_CS	10
#define GDT_ENTRY_LGUEST_DS	11
#define LGUEST_CS		(GDT_ENTRY_LGUEST_CS * 8)
#define LGUEST_DS		(GDT_ENTRY_LGUEST_DS * 8)

#ifndef __ASSEMBLY__
#include <linux/types.h>
#include <linux/init.h>
#include <linux/stringify.h>
#include <linux/binfmts.h>
#include <linux/futex.h>
#include <linux/lguest.h>
#include <linux/lguest_launcher.h>
#include <linux/wait.h>
#include <linux/err.h>
#include <asm/semaphore.h>
#include "irq_vectors.h"

#define GUEST_PL 1

struct lguest_regs
{
	/* Manually saved part. */
	unsigned long ebx, ecx, edx;
	unsigned long esi, edi, ebp;
	unsigned long gs;
	unsigned long eax;
	unsigned long fs, ds, es;
	unsigned long trapnum, errcode;
	/* Trap pushed part */
	unsigned long eip;
	unsigned long cs;
	unsigned long eflags;
	unsigned long esp;
	unsigned long ss;
};

void free_pagetables(void);
int init_pagetables(struct page **switcher_page, unsigned int pages);

/* Full 4G segment descriptors, suitable for CS and DS. */
#define FULL_EXEC_SEGMENT ((struct desc_struct){0x0000ffff, 0x00cf9b00})
#define FULL_SEGMENT ((struct desc_struct){0x0000ffff, 0x00cf9300})

struct lguest_dma_info
{
	struct list_head list;
	union futex_key key;
	unsigned long dmas;
	u16 next_dma;
	u16 num_dmas;
	u16 guestid;
	u8 interrupt; 	/* 0 when not registered */
};

/*H:310 The page-table code owes a great debt of gratitude to Andi Kleen.  He
 * reviewed the original code which used "u32" for all page table entries, and
 * insisted that it would be far clearer with explicit typing.  I thought it
 * was overkill, but he was right: it is much clearer than it was before.
 *
 * We have separate types for the Guest's ptes & pgds and the shadow ptes &
 * pgds.  There's already a Linux type for these (pte_t and pgd_t) but they
 * change depending on kernel config options (PAE). */

/* Each entry is identical: lower 12 bits of flags and upper 20 bits for the
 * "page frame number" (0 == first physical page, etc).  They are different
 * types so the compiler will warn us if we mix them improperly. */
typedef union {
	struct { unsigned flags:12, pfn:20; };
	struct { unsigned long val; } raw;
} spgd_t;
typedef union {
	struct { unsigned flags:12, pfn:20; };
	struct { unsigned long val; } raw;
} spte_t;
typedef union {
	struct { unsigned flags:12, pfn:20; };
	struct { unsigned long val; } raw;
} gpgd_t;
typedef union {
	struct { unsigned flags:12, pfn:20; };
	struct { unsigned long val; } raw;
} gpte_t;

/* We have two convenient macros to convert a "raw" value as handed to us by
 * the Guest into the correct Guest PGD or PTE type. */
#define mkgpte(_val) ((gpte_t){.raw.val = _val})
#define mkgpgd(_val) ((gpgd_t){.raw.val = _val})
/*:*/

struct pgdir
{
	unsigned long cr3;
	spgd_t *pgdir;
};

/* This is a guest-specific page (mapped ro) into the guest. */
struct lguest_ro_state
{
	/* Host information we need to restore when we switch back. */
	u32 host_cr3;
	struct Xgt_desc_struct host_idt_desc;
	struct Xgt_desc_struct host_gdt_desc;
	u32 host_sp;

	/* Fields which are used when guest is running. */
	struct Xgt_desc_struct guest_idt_desc;
	struct Xgt_desc_struct guest_gdt_desc;
	struct i386_hw_tss guest_tss;
	struct desc_struct guest_idt[IDT_ENTRIES];
	struct desc_struct guest_gdt[GDT_ENTRIES];
};

/* We have two pages shared with guests, per cpu.  */
struct lguest_pages
{
	/* This is the stack page mapped rw in guest */
	char spare[PAGE_SIZE - sizeof(struct lguest_regs)];
	struct lguest_regs regs;

	/* This is the host state & guest descriptor page, ro in guest */
	struct lguest_ro_state state;
} __attribute__((aligned(PAGE_SIZE)));

#define CHANGED_IDT		1
#define CHANGED_GDT		2
#define CHANGED_GDT_TLS		4 /* Actually a subset of CHANGED_GDT */
#define CHANGED_ALL	        3

/* The private info the thread maintains about the guest. */
struct lguest
{
	/* At end of a page shared mapped over lguest_pages in guest.  */
	unsigned long regs_page;
	struct lguest_regs *regs;
	struct lguest_data __user *lguest_data;
	struct task_struct *tsk;
	struct mm_struct *mm; 	/* == tsk->mm, but that becomes NULL on exit */
	u16 guestid;
	u32 pfn_limit;
	u32 page_offset;
	u32 cr2;
	int halted;
	int ts;
	u32 next_hcall;
	u32 esp1;
	u8 ss1;

	/* Do we need to stop what we're doing and return to userspace? */
	int break_out;
	wait_queue_head_t break_wq;

	/* Bitmap of what has changed: see CHANGED_* above. */
	int changed;
	struct lguest_pages *last_pages;

	/* We keep a small number of these. */
	u32 pgdidx;
	struct pgdir pgdirs[4];

	/* Cached wakeup: we hold a reference to this task. */
	struct task_struct *wake;

	unsigned long noirq_start, noirq_end;
	int dma_is_pending;
	unsigned long pending_dma; /* struct lguest_dma */
	unsigned long pending_key; /* address they're sending to */

	unsigned int stack_pages;
	u32 tsc_khz;

	struct lguest_dma_info dma[LGUEST_MAX_DMA];

	/* Dead? */
	const char *dead;

	/* The GDT entries copied into lguest_ro_state when running. */
	struct desc_struct gdt[GDT_ENTRIES];

	/* The IDT entries: some copied into lguest_ro_state when running. */
	struct desc_struct idt[FIRST_EXTERNAL_VECTOR+LGUEST_IRQS];
	struct desc_struct syscall_idt;

	/* Virtual clock device */
	struct hrtimer hrt;

	/* Pending virtual interrupts */
	DECLARE_BITMAP(irqs_pending, LGUEST_IRQS);
};

extern struct lguest lguests[];
extern struct mutex lguest_lock;

/* core.c: */
u32 lgread_u32(struct lguest *lg, unsigned long addr);
void lgwrite_u32(struct lguest *lg, unsigned long addr, u32 val);
void lgread(struct lguest *lg, void *buf, unsigned long addr, unsigned len);
void lgwrite(struct lguest *lg, unsigned long, const void *buf, unsigned len);
int find_free_guest(void);
int lguest_address_ok(const struct lguest *lg,
		      unsigned long addr, unsigned long len);
int run_guest(struct lguest *lg, unsigned long __user *user);


/* interrupts_and_traps.c: */
void maybe_do_interrupt(struct lguest *lg);
int deliver_trap(struct lguest *lg, unsigned int num);
void load_guest_idt_entry(struct lguest *lg, unsigned int i, u32 low, u32 hi);
void guest_set_stack(struct lguest *lg, u32 seg, u32 esp, unsigned int pages);
void pin_stack_pages(struct lguest *lg);
void setup_default_idt_entries(struct lguest_ro_state *state,
			       const unsigned long *def);
void copy_traps(const struct lguest *lg, struct desc_struct *idt,
		const unsigned long *def);
void guest_set_clockevent(struct lguest *lg, unsigned long delta);
void init_clockdev(struct lguest *lg);

/* segments.c: */
void setup_default_gdt_entries(struct lguest_ro_state *state);
void setup_guest_gdt(struct lguest *lg);
void load_guest_gdt(struct lguest *lg, unsigned long table, u32 num);
void guest_load_tls(struct lguest *lg, unsigned long tls_array);
void copy_gdt(const struct lguest *lg, struct desc_struct *gdt);
void copy_gdt_tls(const struct lguest *lg, struct desc_struct *gdt);

/* page_tables.c: */
int init_guest_pagetable(struct lguest *lg, unsigned long pgtable);
void free_guest_pagetable(struct lguest *lg);
void guest_new_pagetable(struct lguest *lg, unsigned long pgtable);
void guest_set_pmd(struct lguest *lg, unsigned long cr3, u32 i);
void guest_pagetable_clear_all(struct lguest *lg);
void guest_pagetable_flush_user(struct lguest *lg);
void guest_set_pte(struct lguest *lg, unsigned long cr3,
		   unsigned long vaddr, gpte_t val);
void map_switcher_in_guest(struct lguest *lg, struct lguest_pages *pages);
int demand_page(struct lguest *info, unsigned long cr2, int errcode);
void pin_page(struct lguest *lg, unsigned long vaddr);

/* lguest_user.c: */
int lguest_device_init(void);
void lguest_device_remove(void);

/* io.c: */
void lguest_io_init(void);
int bind_dma(struct lguest *lg,
	     unsigned long key, unsigned long udma, u16 numdmas, u8 interrupt);
void send_dma(struct lguest *info, unsigned long key, unsigned long udma);
void release_all_dma(struct lguest *lg);
unsigned long get_dma_buffer(struct lguest *lg, unsigned long key,
			     unsigned long *interrupt);

/* hypercalls.c: */
void do_hypercalls(struct lguest *lg);
void write_timestamp(struct lguest *lg);

/*L:035
 * Let's step aside for the moment, to study one important routine that's used
 * widely in the Host code.
 *
 * There are many cases where the Guest does something invalid, like pass crap
 * to a hypercall.  Since only the Guest kernel can make hypercalls, it's quite
 * acceptable to simply terminate the Guest and give the Launcher a nicely
 * formatted reason.  It's also simpler for the Guest itself, which doesn't
 * need to check most hypercalls for "success"; if you're still running, it
 * succeeded.
 *
 * Once this is called, the Guest will never run again, so most Host code can
 * call this then continue as if nothing had happened.  This means many
 * functions don't have to explicitly return an error code, which keeps the
 * code simple.
 *
 * It also means that this can be called more than once: only the first one is
 * remembered.  The only trick is that we still need to kill the Guest even if
 * we can't allocate memory to store the reason.  Linux has a neat way of
 * packing error codes into invalid pointers, so we use that here.
 *
 * Like any macro which uses an "if", it is safely wrapped in a run-once "do {
 * } while(0)".
 */
#define kill_guest(lg, fmt...)					\
do {								\
	if (!(lg)->dead) {					\
		(lg)->dead = kasprintf(GFP_ATOMIC, fmt);	\
		if (!(lg)->dead)				\
			(lg)->dead = ERR_PTR(-ENOMEM);		\
	}							\
} while(0)
/* (End of aside) :*/

static inline unsigned long guest_pa(struct lguest *lg, unsigned long vaddr)
{
	return vaddr - lg->page_offset;
}
#endif	/* __ASSEMBLY__ */
#endif	/* _LGUEST_H */