lg.h

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#ifndef _LGUEST_H
#define _LGUEST_H

#ifndef __ASSEMBLY__
#include <linux/types.h>
#include <linux/init.h>
#include <linux/stringify.h>
#include <linux/lguest.h>
#include <linux/lguest_launcher.h>
#include <linux/wait.h>
#include <linux/hrtimer.h>
#include <linux/err.h>
#include <linux/slab.h>

#include <asm/lguest.h>

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

struct pgdir {
    unsigned long gpgdir;
    pgd_t *pgdir;
};

/* 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

struct lg_cpu {
    unsigned int id;
    struct lguest *lg;
    struct task_struct *tsk;
    struct mm_struct *mm;   /* == tsk->mm, but that becomes NULL on exit */

    u32 cr2;
    int ts;
    u32 esp1;
    u16 ss1;

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

    unsigned long pending_notify; /* pfn from LHCALL_NOTIFY */

    /* At end of a page shared mapped over lguest_pages in guest. */
    unsigned long regs_page;
    struct lguest_regs *regs;

    struct lguest_pages *last_pages;

    /* Initialization mode: linear map everything. */
    bool linear_pages;
    int cpu_pgd; /* Which pgd this cpu is currently using */

    /* If a hypercall was asked for, this points to the arguments. */
    struct hcall_args *hcall;
    u32 next_hcall;

    /* Virtual clock device */
    struct hrtimer hrt;

    /* Did the Guest tell us to halt? */
    int halted;

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

    struct lg_cpu_arch arch;
};

struct lg_eventfd {
    unsigned long addr;
    struct eventfd_ctx *event;
};

struct lg_eventfd_map {
    unsigned int num;
    struct lg_eventfd map[];
};

/* The private info the thread maintains about the guest. */
struct lguest {
    struct lguest_data __user *lguest_data;
    struct lg_cpu cpus[NR_CPUS];
    unsigned int nr_cpus;

    u32 pfn_limit;

    /*
     * This provides the offset to the base of guest-physical memory in the
     * Launcher.
     */
    void __user *mem_base;
    unsigned long kernel_address;

    struct pgdir pgdirs[4];

    unsigned long noirq_start, noirq_end;

    unsigned int stack_pages;
    u32 tsc_khz;

    struct lg_eventfd_map *eventfds;

    /* Dead? */
    const char *dead;
};

extern struct mutex lguest_lock;

/* core.c: */
bool lguest_address_ok(const struct lguest *lg,
               unsigned long addr, unsigned long len);
void __lgread(struct lg_cpu *, void *, unsigned long, unsigned);
void __lgwrite(struct lg_cpu *, unsigned long, const void *, unsigned);

/*H:035
 * Using memory-copy operations like that is usually inconvient, so we
 * have the following helper macros which read and write a specific type (often
 * an unsigned long).
 *
 * This reads into a variable of the given type then returns that.
 */
#define lgread(cpu, addr, type)                     \
    ({ type _v; __lgread((cpu), &_v, (addr), sizeof(_v)); _v; })

/* This checks that the variable is of the given type, then writes it out. */
#define lgwrite(cpu, addr, type, val)               \
    do {                            \
        typecheck(type, val);               \
        __lgwrite((cpu), (addr), &(val), sizeof(val));  \
    } while(0)
/* (end of memory access helper routines) :*/

int run_guest(struct lg_cpu *cpu, unsigned long __user *user);

/*
 * Helper macros to obtain the first 12 or the last 20 bits, this is only the
 * first step in the migration to the kernel types.  pte_pfn is already defined
 * in the kernel.
 */
#define pgd_flags(x)    (pgd_val(x) & ~PAGE_MASK)
#define pgd_pfn(x)  (pgd_val(x) >> PAGE_SHIFT)
#define pmd_flags(x)    (pmd_val(x) & ~PAGE_MASK)
#define pmd_pfn(x)  (pmd_val(x) >> PAGE_SHIFT)

/* interrupts_and_traps.c: */
unsigned int interrupt_pending(struct lg_cpu *cpu, bool *more);
void try_deliver_interrupt(struct lg_cpu *cpu, unsigned int irq, bool more);
void set_interrupt(struct lg_cpu *cpu, unsigned int irq);
bool deliver_trap(struct lg_cpu *cpu, unsigned int num);
void load_guest_idt_entry(struct lg_cpu *cpu, unsigned int i,
              u32 low, u32 hi);
void guest_set_stack(struct lg_cpu *cpu, u32 seg, u32 esp, unsigned int pages);
void pin_stack_pages(struct lg_cpu *cpu);
void setup_default_idt_entries(struct lguest_ro_state *state,
                   const unsigned long *def);
void copy_traps(const struct lg_cpu *cpu, struct desc_struct *idt,
        const unsigned long *def);
void guest_set_clockevent(struct lg_cpu *cpu, unsigned long delta);
bool send_notify_to_eventfd(struct lg_cpu *cpu);
void init_clockdev(struct lg_cpu *cpu);
bool check_syscall_vector(struct lguest *lg);
int init_interrupts(void);
void free_interrupts(void);

/* segments.c: */
void setup_default_gdt_entries(struct lguest_ro_state *state);
void setup_guest_gdt(struct lg_cpu *cpu);
void load_guest_gdt_entry(struct lg_cpu *cpu, unsigned int i,
              u32 low, u32 hi);
void guest_load_tls(struct lg_cpu *cpu, unsigned long tls_array);
void copy_gdt(const struct lg_cpu *cpu, struct desc_struct *gdt);
void copy_gdt_tls(const struct lg_cpu *cpu, struct desc_struct *gdt);

/* page_tables.c: */
int init_guest_pagetable(struct lguest *lg);
void free_guest_pagetable(struct lguest *lg);
void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable);
void guest_set_pgd(struct lguest *lg, unsigned long gpgdir, u32 i);
#ifdef CONFIG_X86_PAE
void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 i);
#endif
void guest_pagetable_clear_all(struct lg_cpu *cpu);
void guest_pagetable_flush_user(struct lg_cpu *cpu);
void guest_set_pte(struct lg_cpu *cpu, unsigned long gpgdir,
           unsigned long vaddr, pte_t val);
void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages);
bool demand_page(struct lg_cpu *cpu, unsigned long cr2, int errcode);
void pin_page(struct lg_cpu *cpu, unsigned long vaddr);
unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr);
void page_table_guest_data_init(struct lg_cpu *cpu);

/* <arch>/core.c: */
void lguest_arch_host_init(void);
void lguest_arch_host_fini(void);
void lguest_arch_run_guest(struct lg_cpu *cpu);
void lguest_arch_handle_trap(struct lg_cpu *cpu);
int lguest_arch_init_hypercalls(struct lg_cpu *cpu);
int lguest_arch_do_hcall(struct lg_cpu *cpu, struct hcall_args *args);
void lguest_arch_setup_regs(struct lg_cpu *cpu, unsigned long start);

/* <arch>/switcher.S: */
extern char start_switcher_text[], end_switcher_text[], switch_to_guest[];

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

/* hypercalls.c: */
void do_hypercalls(struct lg_cpu *cpu);
void write_timestamp(struct lg_cpu *cpu);

/*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 can do 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(cpu, fmt...)                 \
do {                                \
    if (!(cpu)->lg->dead) {                 \
        (cpu)->lg->dead = kasprintf(GFP_ATOMIC, fmt);   \
        if (!(cpu)->lg->dead)               \
            (cpu)->lg->dead = ERR_PTR(-ENOMEM); \
    }                           \
} while(0)
/* (End of aside) :*/

#endif  /* __ASSEMBLY__ */
#endif  /* _LGUEST_H */