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 <linux/slab.h>
  14
  15 #include <asm/lguest.h>
  16
  17 struct pgdir {
  18         unsigned long gpgdir;
  19         bool switcher_mapped;
  20         int last_host_cpu;
  21         pgd_t *pgdir;
  22 };
  23
  24 /* We have two pages shared with guests, per cpu.  */
  25 struct lguest_pages {
  26         /* This is the stack page mapped rw in guest */
  27         char spare[PAGE_SIZE - sizeof(struct lguest_regs)];
  28         struct lguest_regs regs;
  29
  30         /* This is the host state & guest descriptor page, ro in guest */
  31         struct lguest_ro_state state;
  32 } __attribute__((aligned(PAGE_SIZE)));
  33
  34 #define CHANGED_IDT             1
  35 #define CHANGED_GDT             2
  36 #define CHANGED_GDT_TLS         4 /* Actually a subset of CHANGED_GDT */
  37 #define CHANGED_ALL             3
  38
  39 struct lg_cpu {
  40         unsigned int id;
  41         struct lguest *lg;
  42         struct task_struct *tsk;
  43         struct mm_struct *mm;   /* == tsk->mm, but that becomes NULL on exit */
  44
  45         u32 cr2;
  46         int ts;
  47         u32 esp1;
  48         u16 ss1;
  49
  50         /* Bitmap of what has changed: see CHANGED_* above. */
  51         int changed;
  52
  53         unsigned long pending_notify; /* pfn from LHCALL_NOTIFY */
  54
  55         /* At end of a page shared mapped over lguest_pages in guest. */
  56         unsigned long regs_page;
  57         struct lguest_regs *regs;
  58
  59         struct lguest_pages *last_pages;
  60
  61         /* Initialization mode: linear map everything. */
  62         bool linear_pages;
  63         int cpu_pgd; /* Which pgd this cpu is currently using */
  64
  65         /* If a hypercall was asked for, this points to the arguments. */
  66         struct hcall_args *hcall;
  67         u32 next_hcall;
  68
  69         /* Virtual clock device */
  70         struct hrtimer hrt;
  71
  72         /* Did the Guest tell us to halt? */
  73         int halted;
  74
  75         /* Pending virtual interrupts */
  76         DECLARE_BITMAP(irqs_pending, LGUEST_IRQS);
  77
  78         struct lg_cpu_arch arch;
  79 };
  80
  81 struct lg_eventfd {
  82         unsigned long addr;
  83         struct eventfd_ctx *event;
  84 };
  85
  86 struct lg_eventfd_map {
  87         unsigned int num;
  88         struct lg_eventfd map[];
  89 };
  90
  91 /* The private info the thread maintains about the guest. */
  92 struct lguest {
  93         struct lguest_data __user *lguest_data;
  94         struct lg_cpu cpus[NR_CPUS];
  95         unsigned int nr_cpus;
  96
  97         u32 pfn_limit;
  98
  99         /*
 100          * This provides the offset to the base of guest-physical memory in the
 101          * Launcher.
 102          */
 103         void __user *mem_base;
 104         unsigned long kernel_address;
 105
 106         struct pgdir pgdirs[4];
 107
 108         unsigned long noirq_start, noirq_end;
 109
 110         unsigned int stack_pages;
 111         u32 tsc_khz;
 112
 113         struct lg_eventfd_map *eventfds;
 114
 115         /* Dead? */
 116         const char *dead;
 117 };
 118
 119 extern struct mutex lguest_lock;
 120
 121 /* core.c: */
 122 bool lguest_address_ok(const struct lguest *lg,
 123                        unsigned long addr, unsigned long len);
 124 void __lgread(struct lg_cpu *, void *, unsigned long, unsigned);
 125 void __lgwrite(struct lg_cpu *, unsigned long, const void *, unsigned);
 126 extern struct page **lg_switcher_pages;
 127
 128 /*H:035
 129  * Using memory-copy operations like that is usually inconvient, so we
 130  * have the following helper macros which read and write a specific type (often
 131  * an unsigned long).
 132  *
 133  * This reads into a variable of the given type then returns that.
 134  */
 135 #define lgread(cpu, addr, type)                                         \
 136         ({ type _v; __lgread((cpu), &_v, (addr), sizeof(_v)); _v; })
 137
 138 /* This checks that the variable is of the given type, then writes it out. */
 139 #define lgwrite(cpu, addr, type, val)                           \
 140         do {                                                    \
 141                 typecheck(type, val);                           \
 142                 __lgwrite((cpu), (addr), &(val), sizeof(val));  \
 143         } while(0)
 144 /* (end of memory access helper routines) :*/
 145
 146 int run_guest(struct lg_cpu *cpu, unsigned long __user *user);
 147
 148 /*
 149  * Helper macros to obtain the first 12 or the last 20 bits, this is only the
 150  * first step in the migration to the kernel types.  pte_pfn is already defined
 151  * in the kernel.
 152  */
 153 #define pgd_flags(x)    (pgd_val(x) & ~PAGE_MASK)
 154 #define pgd_pfn(x)      (pgd_val(x) >> PAGE_SHIFT)
 155 #define pmd_flags(x)    (pmd_val(x) & ~PAGE_MASK)
 156 #define pmd_pfn(x)      (pmd_val(x) >> PAGE_SHIFT)
 157
 158 /* interrupts_and_traps.c: */
 159 unsigned int interrupt_pending(struct lg_cpu *cpu, bool *more);
 160 void try_deliver_interrupt(struct lg_cpu *cpu, unsigned int irq, bool more);
 161 void set_interrupt(struct lg_cpu *cpu, unsigned int irq);
 162 bool deliver_trap(struct lg_cpu *cpu, unsigned int num);
 163 void load_guest_idt_entry(struct lg_cpu *cpu, unsigned int i,
 164                           u32 low, u32 hi);
 165 void guest_set_stack(struct lg_cpu *cpu, u32 seg, u32 esp, unsigned int pages);
 166 void pin_stack_pages(struct lg_cpu *cpu);
 167 void setup_default_idt_entries(struct lguest_ro_state *state,
 168                                const unsigned long *def);
 169 void copy_traps(const struct lg_cpu *cpu, struct desc_struct *idt,
 170                 const unsigned long *def);
 171 void guest_set_clockevent(struct lg_cpu *cpu, unsigned long delta);
 172 bool send_notify_to_eventfd(struct lg_cpu *cpu);
 173 void init_clockdev(struct lg_cpu *cpu);
 174 bool check_syscall_vector(struct lguest *lg);
 175 int init_interrupts(void);
 176 void free_interrupts(void);
 177
 178 /* segments.c: */
 179 void setup_default_gdt_entries(struct lguest_ro_state *state);
 180 void setup_guest_gdt(struct lg_cpu *cpu);
 181 void load_guest_gdt_entry(struct lg_cpu *cpu, unsigned int i,
 182                           u32 low, u32 hi);
 183 void guest_load_tls(struct lg_cpu *cpu, unsigned long tls_array);
 184 void copy_gdt(const struct lg_cpu *cpu, struct desc_struct *gdt);
 185 void copy_gdt_tls(const struct lg_cpu *cpu, struct desc_struct *gdt);
 186
 187 /* page_tables.c: */
 188 int init_guest_pagetable(struct lguest *lg);
 189 void free_guest_pagetable(struct lguest *lg);
 190 void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable);
 191 void guest_set_pgd(struct lguest *lg, unsigned long gpgdir, u32 i);
 192 #ifdef CONFIG_X86_PAE
 193 void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 i);
 194 #endif
 195 void guest_pagetable_clear_all(struct lg_cpu *cpu);
 196 void guest_pagetable_flush_user(struct lg_cpu *cpu);
 197 void guest_set_pte(struct lg_cpu *cpu, unsigned long gpgdir,
 198                    unsigned long vaddr, pte_t val);
 199 void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages);
 200 bool demand_page(struct lg_cpu *cpu, unsigned long cr2, int errcode);
 201 void pin_page(struct lg_cpu *cpu, unsigned long vaddr);
 202 unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr);
 203 void page_table_guest_data_init(struct lg_cpu *cpu);
 204
 205 /* <arch>/core.c: */
 206 void lguest_arch_host_init(void);
 207 void lguest_arch_host_fini(void);
 208 void lguest_arch_run_guest(struct lg_cpu *cpu);
 209 void lguest_arch_handle_trap(struct lg_cpu *cpu);
 210 int lguest_arch_init_hypercalls(struct lg_cpu *cpu);
 211 int lguest_arch_do_hcall(struct lg_cpu *cpu, struct hcall_args *args);
 212 void lguest_arch_setup_regs(struct lg_cpu *cpu, unsigned long start);
 213
 214 /* <arch>/switcher.S: */
 215 extern char start_switcher_text[], end_switcher_text[], switch_to_guest[];
 216
 217 /* lguest_user.c: */
 218 int lguest_device_init(void);
 219 void lguest_device_remove(void);
 220
 221 /* hypercalls.c: */
 222 void do_hypercalls(struct lg_cpu *cpu);
 223 void write_timestamp(struct lg_cpu *cpu);
 224
 225 /*L:035
 226  * Let's step aside for the moment, to study one important routine that's used
 227  * widely in the Host code.
 228  *
 229  * There are many cases where the Guest can do something invalid, like pass crap
 230  * to a hypercall.  Since only the Guest kernel can make hypercalls, it's quite
 231  * acceptable to simply terminate the Guest and give the Launcher a nicely
 232  * formatted reason.  It's also simpler for the Guest itself, which doesn't
 233  * need to check most hypercalls for "success"; if you're still running, it
 234  * succeeded.
 235  *
 236  * Once this is called, the Guest will never run again, so most Host code can
 237  * call this then continue as if nothing had happened.  This means many
 238  * functions don't have to explicitly return an error code, which keeps the
 239  * code simple.
 240  *
 241  * It also means that this can be called more than once: only the first one is
 242  * remembered.  The only trick is that we still need to kill the Guest even if
 243  * we can't allocate memory to store the reason.  Linux has a neat way of
 244  * packing error codes into invalid pointers, so we use that here.
 245  *
 246  * Like any macro which uses an "if", it is safely wrapped in a run-once "do {
 247  * } while(0)".
 248  */
 249 #define kill_guest(cpu, fmt...)                                 \
 250 do {                                                            \
 251         if (!(cpu)->lg->dead) {                                 \
 252                 (cpu)->lg->dead = kasprintf(GFP_ATOMIC, fmt);   \
 253                 if (!(cpu)->lg->dead)                           \
 254                         (cpu)->lg->dead = ERR_PTR(-ENOMEM);     \
 255         }                                                       \
 256 } while(0)
 257 /* (End of aside) :*/
 258
 259 #endif  /* __ASSEMBLY__ */
 260 #endif  /* _LGUEST_H */