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 #include <asm/semaphore.h>
  14
  15 #include <asm/lguest.h>
  16
  17 void free_pagetables(void);
  18 int init_pagetables(struct page **switcher_page, unsigned int pages);
  19
  20 struct pgdir
  21 {
  22         unsigned long gpgdir;
  23         pgd_t *pgdir;
  24 };
  25
  26 /* We have two pages shared with guests, per cpu.  */
  27 struct lguest_pages
  28 {
  29         /* This is the stack page mapped rw in guest */
  30         char spare[PAGE_SIZE - sizeof(struct lguest_regs)];
  31         struct lguest_regs regs;
  32
  33         /* This is the host state & guest descriptor page, ro in guest */
  34         struct lguest_ro_state state;
  35 } __attribute__((aligned(PAGE_SIZE)));
  36
  37 #define CHANGED_IDT             1
  38 #define CHANGED_GDT             2
  39 #define CHANGED_GDT_TLS         4 /* Actually a subset of CHANGED_GDT */
  40 #define CHANGED_ALL             3
  41
  42 struct lguest;
  43
  44 struct lg_cpu {
  45         unsigned int id;
  46         struct lguest *lg;
  47         struct task_struct *tsk;
  48         struct mm_struct *mm;   /* == tsk->mm, but that becomes NULL on exit */
  49
  50         u32 cr2;
  51         int ts;
  52         u32 esp1;
  53         u8 ss1;
  54
  55         /* Bitmap of what has changed: see CHANGED_* above. */
  56         int changed;
  57
  58         unsigned long pending_notify; /* pfn from LHCALL_NOTIFY */
  59
  60         /* At end of a page shared mapped over lguest_pages in guest.  */
  61         unsigned long regs_page;
  62         struct lguest_regs *regs;
  63
  64         struct lguest_pages *last_pages;
  65
  66         int cpu_pgd; /* which pgd this cpu is currently using */
  67
  68         /* If a hypercall was asked for, this points to the arguments. */
  69         struct hcall_args *hcall;
  70         u32 next_hcall;
  71
  72         /* Virtual clock device */
  73         struct hrtimer hrt;
  74
  75         /* Do we need to stop what we're doing and return to userspace? */
  76         int break_out;
  77         wait_queue_head_t break_wq;
  78         int halted;
  79
  80         /* Pending virtual interrupts */
  81         DECLARE_BITMAP(irqs_pending, LGUEST_IRQS);
  82
  83         struct lg_cpu_arch arch;
  84 };
  85
  86 /* The private info the thread maintains about the guest. */
  87 struct lguest
  88 {
  89         struct lguest_data __user *lguest_data;
  90         struct lg_cpu cpus[NR_CPUS];
  91         unsigned int nr_cpus;
  92
  93         u32 pfn_limit;
  94         /* This provides the offset to the base of guest-physical
  95          * memory in the Launcher. */
  96         void __user *mem_base;
  97         unsigned long kernel_address;
  98
  99         struct pgdir pgdirs[4];
 100
 101         unsigned long noirq_start, noirq_end;
 102
 103         unsigned int stack_pages;
 104         u32 tsc_khz;
 105
 106         /* Dead? */
 107         const char *dead;
 108 };
 109
 110 extern struct mutex lguest_lock;
 111
 112 /* core.c: */
 113 int lguest_address_ok(const struct lguest *lg,
 114                       unsigned long addr, unsigned long len);
 115 void __lgread(struct lg_cpu *, void *, unsigned long, unsigned);
 116 void __lgwrite(struct lg_cpu *, unsigned long, const void *, unsigned);
 117
 118 /*H:035 Using memory-copy operations like that is usually inconvient, so we
 119  * have the following helper macros which read and write a specific type (often
 120  * an unsigned long).
 121  *
 122  * This reads into a variable of the given type then returns that. */
 123 #define lgread(cpu, addr, type)                                         \
 124         ({ type _v; __lgread((cpu), &_v, (addr), sizeof(_v)); _v; })
 125
 126 /* This checks that the variable is of the given type, then writes it out. */
 127 #define lgwrite(cpu, addr, type, val)                           \
 128         do {                                                    \
 129                 typecheck(type, val);                           \
 130                 __lgwrite((cpu), (addr), &(val), sizeof(val));  \
 131         } while(0)
 132 /* (end of memory access helper routines) :*/
 133
 134 int run_guest(struct lg_cpu *cpu, unsigned long __user *user);
 135
 136 /* Helper macros to obtain the first 12 or the last 20 bits, this is only the
 137  * first step in the migration to the kernel types.  pte_pfn is already defined
 138  * in the kernel. */
 139 #define pgd_flags(x)    (pgd_val(x) & ~PAGE_MASK)
 140 #define pte_flags(x)    (pte_val(x) & ~PAGE_MASK)
 141 #define pgd_pfn(x)      (pgd_val(x) >> PAGE_SHIFT)
 142
 143 /* interrupts_and_traps.c: */
 144 void maybe_do_interrupt(struct lg_cpu *cpu);
 145 int deliver_trap(struct lg_cpu *cpu, unsigned int num);
 146 void load_guest_idt_entry(struct lg_cpu *cpu, unsigned int i,
 147                           u32 low, u32 hi);
 148 void guest_set_stack(struct lg_cpu *cpu, u32 seg, u32 esp, unsigned int pages);
 149 void pin_stack_pages(struct lg_cpu *cpu);
 150 void setup_default_idt_entries(struct lguest_ro_state *state,
 151                                const unsigned long *def);
 152 void copy_traps(const struct lg_cpu *cpu, struct desc_struct *idt,
 153                 const unsigned long *def);
 154 void guest_set_clockevent(struct lg_cpu *cpu, unsigned long delta);
 155 void init_clockdev(struct lg_cpu *cpu);
 156 bool check_syscall_vector(struct lguest *lg);
 157 int init_interrupts(void);
 158 void free_interrupts(void);
 159
 160 /* segments.c: */
 161 void setup_default_gdt_entries(struct lguest_ro_state *state);
 162 void setup_guest_gdt(struct lg_cpu *cpu);
 163 void load_guest_gdt(struct lg_cpu *cpu, unsigned long table, u32 num);
 164 void guest_load_tls(struct lg_cpu *cpu, unsigned long tls_array);
 165 void copy_gdt(const struct lg_cpu *cpu, struct desc_struct *gdt);
 166 void copy_gdt_tls(const struct lg_cpu *cpu, struct desc_struct *gdt);
 167
 168 /* page_tables.c: */
 169 int init_guest_pagetable(struct lguest *lg, unsigned long pgtable);
 170 void free_guest_pagetable(struct lguest *lg);
 171 void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable);
 172 void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 i);
 173 void guest_pagetable_clear_all(struct lg_cpu *cpu);
 174 void guest_pagetable_flush_user(struct lg_cpu *cpu);
 175 void guest_set_pte(struct lg_cpu *cpu, unsigned long gpgdir,
 176                    unsigned long vaddr, pte_t val);
 177 void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages);
 178 int demand_page(struct lg_cpu *cpu, unsigned long cr2, int errcode);
 179 void pin_page(struct lg_cpu *cpu, unsigned long vaddr);
 180 unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr);
 181 void page_table_guest_data_init(struct lg_cpu *cpu);
 182
 183 /* <arch>/core.c: */
 184 void lguest_arch_host_init(void);
 185 void lguest_arch_host_fini(void);
 186 void lguest_arch_run_guest(struct lg_cpu *cpu);
 187 void lguest_arch_handle_trap(struct lg_cpu *cpu);
 188 int lguest_arch_init_hypercalls(struct lg_cpu *cpu);
 189 int lguest_arch_do_hcall(struct lg_cpu *cpu, struct hcall_args *args);
 190 void lguest_arch_setup_regs(struct lg_cpu *cpu, unsigned long start);
 191
 192 /* <arch>/switcher.S: */
 193 extern char start_switcher_text[], end_switcher_text[], switch_to_guest[];
 194
 195 /* lguest_user.c: */
 196 int lguest_device_init(void);
 197 void lguest_device_remove(void);
 198
 199 /* hypercalls.c: */
 200 void do_hypercalls(struct lg_cpu *cpu);
 201 void write_timestamp(struct lg_cpu *cpu);
 202
 203 /*L:035
 204  * Let's step aside for the moment, to study one important routine that's used
 205  * widely in the Host code.
 206  *
 207  * There are many cases where the Guest can do something invalid, like pass crap
 208  * to a hypercall.  Since only the Guest kernel can make hypercalls, it's quite
 209  * acceptable to simply terminate the Guest and give the Launcher a nicely
 210  * formatted reason.  It's also simpler for the Guest itself, which doesn't
 211  * need to check most hypercalls for "success"; if you're still running, it
 212  * succeeded.
 213  *
 214  * Once this is called, the Guest will never run again, so most Host code can
 215  * call this then continue as if nothing had happened.  This means many
 216  * functions don't have to explicitly return an error code, which keeps the
 217  * code simple.
 218  *
 219  * It also means that this can be called more than once: only the first one is
 220  * remembered.  The only trick is that we still need to kill the Guest even if
 221  * we can't allocate memory to store the reason.  Linux has a neat way of
 222  * packing error codes into invalid pointers, so we use that here.
 223  *
 224  * Like any macro which uses an "if", it is safely wrapped in a run-once "do {
 225  * } while(0)".
 226  */
 227 #define kill_guest(cpu, fmt...)                                 \
 228 do {                                                            \
 229         if (!(cpu)->lg->dead) {                                 \
 230                 (cpu)->lg->dead = kasprintf(GFP_ATOMIC, fmt);   \
 231                 if (!(cpu)->lg->dead)                           \
 232                         (cpu)->lg->dead = ERR_PTR(-ENOMEM);     \
 233         }                                                       \
 234 } while(0)
 235 /* (End of aside) :*/
 236
 237 #endif  /* __ASSEMBLY__ */
 238 #endif  /* _LGUEST_H */