drivers/lguest/lg.h

   1 #ifndef _LGUEST_H
   2 #define _LGUEST_H
   3
   4 #ifndef __ASSEMBLY__
   5 #include <linux/types.h>
   6 #include <linux/init.h>
   7 #include <linux/stringify.h>
   8 #include <linux/lguest.h>
   9 #include <linux/lguest_launcher.h>
  10 #include <linux/wait.h>
  11 #include <linux/err.h>
  12 #include <asm/semaphore.h>
  13
  14 #include <asm/lguest.h>
  15
  16 void free_pagetables(void);
  17 int init_pagetables(struct page **switcher_page, unsigned int pages);
  18
  19 struct pgdir
  20 {
  21         unsigned long gpgdir;
  22         pgd_t *pgdir;
  23 };
  24
  25 /* We have two pages shared with guests, per cpu.  */
  26 struct lguest_pages
  27 {
  28         /* This is the stack page mapped rw in guest */
  29         char spare[PAGE_SIZE - sizeof(struct lguest_regs)];
  30         struct lguest_regs regs;
  31
  32         /* This is the host state & guest descriptor page, ro in guest */
  33         struct lguest_ro_state state;
  34 } __attribute__((aligned(PAGE_SIZE)));
  35
  36 #define CHANGED_IDT             1
  37 #define CHANGED_GDT             2
  38 #define CHANGED_GDT_TLS         4 /* Actually a subset of CHANGED_GDT */
  39 #define CHANGED_ALL             3
  40
  41 /* The private info the thread maintains about the guest. */
  42 struct lguest
  43 {
  44         /* At end of a page shared mapped over lguest_pages in guest.  */
  45         unsigned long regs_page;
  46         struct lguest_regs *regs;
  47         struct lguest_data __user *lguest_data;
  48         struct task_struct *tsk;
  49         struct mm_struct *mm;   /* == tsk->mm, but that becomes NULL on exit */
  50         u32 pfn_limit;
  51         /* This provides the offset to the base of guest-physical
  52          * memory in the Launcher. */
  53         void __user *mem_base;
  54         unsigned long kernel_address;
  55         u32 cr2;
  56         int halted;
  57         int ts;
  58         u32 next_hcall;
  59         u32 esp1;
  60         u8 ss1;
  61
  62         /* If a hypercall was asked for, this points to the arguments. */
  63         struct hcall_args *hcall;
  64
  65         /* Do we need to stop what we're doing and return to userspace? */
  66         int break_out;
  67         wait_queue_head_t break_wq;
  68
  69         /* Bitmap of what has changed: see CHANGED_* above. */
  70         int changed;
  71         struct lguest_pages *last_pages;
  72
  73         /* We keep a small number of these. */
  74         u32 pgdidx;
  75         struct pgdir pgdirs[4];
  76
  77         /* Cached wakeup: we hold a reference to this task. */
  78         struct task_struct *wake;
  79
  80         unsigned long noirq_start, noirq_end;
  81         unsigned long pending_notify; /* pfn from LHCALL_NOTIFY */
  82
  83         unsigned int stack_pages;
  84         u32 tsc_khz;
  85
  86         /* Dead? */
  87         const char *dead;
  88
  89         struct lguest_arch arch;
  90
  91         /* Virtual clock device */
  92         struct hrtimer hrt;
  93
  94         /* Pending virtual interrupts */
  95         DECLARE_BITMAP(irqs_pending, LGUEST_IRQS);
  96 };
  97
  98 extern struct mutex lguest_lock;
  99
 100 /* core.c: */
 101 int lguest_address_ok(const struct lguest *lg,
 102                       unsigned long addr, unsigned long len);
 103 void __lgread(struct lguest *, void *, unsigned long, unsigned);
 104 void __lgwrite(struct lguest *, unsigned long, const void *, unsigned);
 105
 106 /*L:306 Using memory-copy operations like that is usually inconvient, so we
 107  * have the following helper macros which read and write a specific type (often
 108  * an unsigned long).
 109  *
 110  * This reads into a variable of the given type then returns that. */
 111 #define lgread(lg, addr, type)                                          \
 112         ({ type _v; __lgread((lg), &_v, (addr), sizeof(_v)); _v; })
 113
 114 /* This checks that the variable is of the given type, then writes it out. */
 115 #define lgwrite(lg, addr, type, val)                            \
 116         do {                                                    \
 117                 typecheck(type, val);                           \
 118                 __lgwrite((lg), (addr), &(val), sizeof(val));   \
 119         } while(0)
 120 /* (end of memory access helper routines) :*/
 121
 122 int run_guest(struct lguest *lg, unsigned long __user *user);
 123
 124 /* Helper macros to obtain the first 12 or the last 20 bits, this is only the
 125  * first step in the migration to the kernel types.  pte_pfn is already defined
 126  * in the kernel. */
 127 #define pgd_flags(x)    (pgd_val(x) & ~PAGE_MASK)
 128 #define pte_flags(x)    (pte_val(x) & ~PAGE_MASK)
 129 #define pgd_pfn(x)      (pgd_val(x) >> PAGE_SHIFT)
 130
 131 /* interrupts_and_traps.c: */
 132 void maybe_do_interrupt(struct lguest *lg);
 133 int deliver_trap(struct lguest *lg, unsigned int num);
 134 void load_guest_idt_entry(struct lguest *lg, unsigned int i, u32 low, u32 hi);
 135 void guest_set_stack(struct lguest *lg, u32 seg, u32 esp, unsigned int pages);
 136 void pin_stack_pages(struct lguest *lg);
 137 void setup_default_idt_entries(struct lguest_ro_state *state,
 138                                const unsigned long *def);
 139 void copy_traps(const struct lguest *lg, struct desc_struct *idt,
 140                 const unsigned long *def);
 141 void guest_set_clockevent(struct lguest *lg, unsigned long delta);
 142 void init_clockdev(struct lguest *lg);
 143 bool check_syscall_vector(struct lguest *lg);
 144 int init_interrupts(void);
 145 void free_interrupts(void);
 146
 147 /* segments.c: */
 148 void setup_default_gdt_entries(struct lguest_ro_state *state);
 149 void setup_guest_gdt(struct lguest *lg);
 150 void load_guest_gdt(struct lguest *lg, unsigned long table, u32 num);
 151 void guest_load_tls(struct lguest *lg, unsigned long tls_array);
 152 void copy_gdt(const struct lguest *lg, struct desc_struct *gdt);
 153 void copy_gdt_tls(const struct lguest *lg, struct desc_struct *gdt);
 154
 155 /* page_tables.c: */
 156 int init_guest_pagetable(struct lguest *lg, unsigned long pgtable);
 157 void free_guest_pagetable(struct lguest *lg);
 158 void guest_new_pagetable(struct lguest *lg, unsigned long pgtable);
 159 void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 i);
 160 void guest_pagetable_clear_all(struct lguest *lg);
 161 void guest_pagetable_flush_user(struct lguest *lg);
 162 void guest_set_pte(struct lguest *lg, unsigned long gpgdir,
 163                    unsigned long vaddr, pte_t val);
 164 void map_switcher_in_guest(struct lguest *lg, struct lguest_pages *pages);
 165 int demand_page(struct lguest *info, unsigned long cr2, int errcode);
 166 void pin_page(struct lguest *lg, unsigned long vaddr);
 167 unsigned long guest_pa(struct lguest *lg, unsigned long vaddr);
 168 void page_table_guest_data_init(struct lguest *lg);
 169
 170 /* <arch>/core.c: */
 171 void lguest_arch_host_init(void);
 172 void lguest_arch_host_fini(void);
 173 void lguest_arch_run_guest(struct lguest *lg);
 174 void lguest_arch_handle_trap(struct lguest *lg);
 175 int lguest_arch_init_hypercalls(struct lguest *lg);
 176 int lguest_arch_do_hcall(struct lguest *lg, struct hcall_args *args);
 177 void lguest_arch_setup_regs(struct lguest *lg, unsigned long start);
 178
 179 /* <arch>/switcher.S: */
 180 extern char start_switcher_text[], end_switcher_text[], switch_to_guest[];
 181
 182 /* lguest_user.c: */
 183 int lguest_device_init(void);
 184 void lguest_device_remove(void);
 185
 186 /* hypercalls.c: */
 187 void do_hypercalls(struct lguest *lg);
 188 void write_timestamp(struct lguest *lg);
 189
 190 /*L:035
 191  * Let's step aside for the moment, to study one important routine that's used
 192  * widely in the Host code.
 193  *
 194  * There are many cases where the Guest does something invalid, like pass crap
 195  * to a hypercall.  Since only the Guest kernel can make hypercalls, it's quite
 196  * acceptable to simply terminate the Guest and give the Launcher a nicely
 197  * formatted reason.  It's also simpler for the Guest itself, which doesn't
 198  * need to check most hypercalls for "success"; if you're still running, it
 199  * succeeded.
 200  *
 201  * Once this is called, the Guest will never run again, so most Host code can
 202  * call this then continue as if nothing had happened.  This means many
 203  * functions don't have to explicitly return an error code, which keeps the
 204  * code simple.
 205  *
 206  * It also means that this can be called more than once: only the first one is
 207  * remembered.  The only trick is that we still need to kill the Guest even if
 208  * we can't allocate memory to store the reason.  Linux has a neat way of
 209  * packing error codes into invalid pointers, so we use that here.
 210  *
 211  * Like any macro which uses an "if", it is safely wrapped in a run-once "do {
 212  * } while(0)".
 213  */
 214 #define kill_guest(lg, fmt...)                                  \
 215 do {                                                            \
 216         if (!(lg)->dead) {                                      \
 217                 (lg)->dead = kasprintf(GFP_ATOMIC, fmt);        \
 218                 if (!(lg)->dead)                                \
 219                         (lg)->dead = ERR_PTR(-ENOMEM);          \
 220         }                                                       \
 221 } while(0)
 222 /* (End of aside) :*/
 223
 224 #endif  /* __ASSEMBLY__ */
 225 #endif  /* _LGUEST_H */