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