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 struct lguest;
  42
  43 struct lg_cpu {
  44         unsigned int id;
  45         struct lguest *lg;
  46
  47         /* At end of a page shared mapped over lguest_pages in guest.  */
  48         unsigned long regs_page;
  49         struct lguest_regs *regs;
  50
  51         /* If a hypercall was asked for, this points to the arguments. */
  52         struct hcall_args *hcall;
  53         u32 next_hcall;
  54
  55         /* Virtual clock device */
  56         struct hrtimer hrt;
  57
  58         /* Pending virtual interrupts */
  59         DECLARE_BITMAP(irqs_pending, LGUEST_IRQS);
  60
  61         struct lg_cpu_arch arch;
  62 };
  63
  64 /* The private info the thread maintains about the guest. */
  65 struct lguest
  66 {
  67         struct lguest_data __user *lguest_data;
  68         struct task_struct *tsk;
  69         struct mm_struct *mm;   /* == tsk->mm, but that becomes NULL on exit */
  70         struct lg_cpu cpus[NR_CPUS];
  71         unsigned int nr_cpus;
  72
  73         u32 pfn_limit;
  74         /* This provides the offset to the base of guest-physical
  75          * memory in the Launcher. */
  76         void __user *mem_base;
  77         unsigned long kernel_address;
  78         u32 cr2;
  79         int halted;
  80         int ts;
  81         u32 esp1;
  82         u8 ss1;
  83
  84         /* Do we need to stop what we're doing and return to userspace? */
  85         int break_out;
  86         wait_queue_head_t break_wq;
  87
  88         /* Bitmap of what has changed: see CHANGED_* above. */
  89         int changed;
  90         struct lguest_pages *last_pages;
  91
  92         /* We keep a small number of these. */
  93         u32 pgdidx;
  94         struct pgdir pgdirs[4];
  95
  96         unsigned long noirq_start, noirq_end;
  97         unsigned long pending_notify; /* pfn from LHCALL_NOTIFY */
  98
  99         unsigned int stack_pages;
 100         u32 tsc_khz;
 101
 102         /* Dead? */
 103         const char *dead;
 104 };
 105
 106 extern struct mutex lguest_lock;
 107
 108 /* core.c: */
 109 int lguest_address_ok(const struct lguest *lg,
 110                       unsigned long addr, unsigned long len);
 111 void __lgread(struct lguest *, void *, unsigned long, unsigned);
 112 void __lgwrite(struct lguest *, unsigned long, const void *, unsigned);
 113
 114 /*H:035 Using memory-copy operations like that is usually inconvient, so we
 115  * have the following helper macros which read and write a specific type (often
 116  * an unsigned long).
 117  *
 118  * This reads into a variable of the given type then returns that. */
 119 #define lgread(lg, addr, type)                                          \
 120         ({ type _v; __lgread((lg), &_v, (addr), sizeof(_v)); _v; })
 121
 122 /* This checks that the variable is of the given type, then writes it out. */
 123 #define lgwrite(lg, addr, type, val)                            \
 124         do {                                                    \
 125                 typecheck(type, val);                           \
 126                 __lgwrite((lg), (addr), &(val), sizeof(val));   \
 127         } while(0)
 128 /* (end of memory access helper routines) :*/
 129
 130 int run_guest(struct lg_cpu *cpu, unsigned long __user *user);
 131
 132 /* Helper macros to obtain the first 12 or the last 20 bits, this is only the
 133  * first step in the migration to the kernel types.  pte_pfn is already defined
 134  * in the kernel. */
 135 #define pgd_flags(x)    (pgd_val(x) & ~PAGE_MASK)
 136 #define pte_flags(x)    (pte_val(x) & ~PAGE_MASK)
 137 #define pgd_pfn(x)      (pgd_val(x) >> PAGE_SHIFT)
 138
 139 /* interrupts_and_traps.c: */
 140 void maybe_do_interrupt(struct lg_cpu *cpu);
 141 int deliver_trap(struct lg_cpu *cpu, unsigned int num);
 142 void load_guest_idt_entry(struct lg_cpu *cpu, unsigned int i,
 143                           u32 low, u32 hi);
 144 void guest_set_stack(struct lguest *lg, u32 seg, u32 esp, unsigned int pages);
 145 void pin_stack_pages(struct lguest *lg);
 146 void setup_default_idt_entries(struct lguest_ro_state *state,
 147                                const unsigned long *def);
 148 void copy_traps(const struct lg_cpu *cpu, struct desc_struct *idt,
 149                 const unsigned long *def);
 150 void guest_set_clockevent(struct lg_cpu *cpu, unsigned long delta);
 151 void init_clockdev(struct lg_cpu *cpu);
 152 bool check_syscall_vector(struct lguest *lg);
 153 int init_interrupts(void);
 154 void free_interrupts(void);
 155
 156 /* segments.c: */
 157 void setup_default_gdt_entries(struct lguest_ro_state *state);
 158 void setup_guest_gdt(struct lg_cpu *cpu);
 159 void load_guest_gdt(struct lg_cpu *cpu, unsigned long table, u32 num);
 160 void guest_load_tls(struct lg_cpu *cpu, unsigned long tls_array);
 161 void copy_gdt(const struct lg_cpu *cpu, struct desc_struct *gdt);
 162 void copy_gdt_tls(const struct lg_cpu *cpu, struct desc_struct *gdt);
 163
 164 /* page_tables.c: */
 165 int init_guest_pagetable(struct lguest *lg, unsigned long pgtable);
 166 void free_guest_pagetable(struct lguest *lg);
 167 void guest_new_pagetable(struct lguest *lg, unsigned long pgtable);
 168 void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 i);
 169 void guest_pagetable_clear_all(struct lguest *lg);
 170 void guest_pagetable_flush_user(struct lguest *lg);
 171 void guest_set_pte(struct lguest *lg, unsigned long gpgdir,
 172                    unsigned long vaddr, pte_t val);
 173 void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages);
 174 int demand_page(struct lguest *info, unsigned long cr2, int errcode);
 175 void pin_page(struct lguest *lg, unsigned long vaddr);
 176 unsigned long guest_pa(struct lguest *lg, unsigned long vaddr);
 177 void page_table_guest_data_init(struct lguest *lg);
 178
 179 /* <arch>/core.c: */
 180 void lguest_arch_host_init(void);
 181 void lguest_arch_host_fini(void);
 182 void lguest_arch_run_guest(struct lg_cpu *cpu);
 183 void lguest_arch_handle_trap(struct lg_cpu *cpu);
 184 int lguest_arch_init_hypercalls(struct lg_cpu *cpu);
 185 int lguest_arch_do_hcall(struct lg_cpu *cpu, struct hcall_args *args);
 186 void lguest_arch_setup_regs(struct lg_cpu *cpu, unsigned long start);
 187
 188 /* <arch>/switcher.S: */
 189 extern char start_switcher_text[], end_switcher_text[], switch_to_guest[];
 190
 191 /* lguest_user.c: */
 192 int lguest_device_init(void);
 193 void lguest_device_remove(void);
 194
 195 /* hypercalls.c: */
 196 void do_hypercalls(struct lg_cpu *cpu);
 197 void write_timestamp(struct lguest *lg);
 198
 199 /*L:035
 200  * Let's step aside for the moment, to study one important routine that's used
 201  * widely in the Host code.
 202  *
 203  * There are many cases where the Guest can do something invalid, like pass crap
 204  * to a hypercall.  Since only the Guest kernel can make hypercalls, it's quite
 205  * acceptable to simply terminate the Guest and give the Launcher a nicely
 206  * formatted reason.  It's also simpler for the Guest itself, which doesn't
 207  * need to check most hypercalls for "success"; if you're still running, it
 208  * succeeded.
 209  *
 210  * Once this is called, the Guest will never run again, so most Host code can
 211  * call this then continue as if nothing had happened.  This means many
 212  * functions don't have to explicitly return an error code, which keeps the
 213  * code simple.
 214  *
 215  * It also means that this can be called more than once: only the first one is
 216  * remembered.  The only trick is that we still need to kill the Guest even if
 217  * we can't allocate memory to store the reason.  Linux has a neat way of
 218  * packing error codes into invalid pointers, so we use that here.
 219  *
 220  * Like any macro which uses an "if", it is safely wrapped in a run-once "do {
 221  * } while(0)".
 222  */
 223 #define kill_guest(lg, fmt...)                                  \
 224 do {                                                            \
 225         if (!(lg)->dead) {                                      \
 226                 (lg)->dead = kasprintf(GFP_ATOMIC, fmt);        \
 227                 if (!(lg)->dead)                                \
 228                         (lg)->dead = ERR_PTR(-ENOMEM);          \
 229         }                                                       \
 230 } while(0)
 231 /* (End of aside) :*/
 232
 233 #endif  /* __ASSEMBLY__ */
 234 #endif  /* _LGUEST_H */