drivers/lguest/lg.h

   1 #ifndef _LGUEST_H
   2 #define _LGUEST_H
   3
   4 #include <asm/desc.h>
   5
   6 #define GDT_ENTRY_LGUEST_CS     10
   7 #define GDT_ENTRY_LGUEST_DS     11
   8 #define LGUEST_CS               (GDT_ENTRY_LGUEST_CS * 8)
   9 #define LGUEST_DS               (GDT_ENTRY_LGUEST_DS * 8)
  10
  11 #ifndef __ASSEMBLY__
  12 #include <linux/types.h>
  13 #include <linux/init.h>
  14 #include <linux/stringify.h>
  15 #include <linux/binfmts.h>
  16 #include <linux/futex.h>
  17 #include <linux/lguest.h>
  18 #include <linux/lguest_launcher.h>
  19 #include <linux/wait.h>
  20 #include <linux/err.h>
  21 #include <asm/semaphore.h>
  22 #include "irq_vectors.h"
  23
  24 #define GUEST_PL 1
  25
  26 struct lguest_regs
  27 {
  28         /* Manually saved part. */
  29         unsigned long ebx, ecx, edx;
  30         unsigned long esi, edi, ebp;
  31         unsigned long gs;
  32         unsigned long eax;
  33         unsigned long fs, ds, es;
  34         unsigned long trapnum, errcode;
  35         /* Trap pushed part */
  36         unsigned long eip;
  37         unsigned long cs;
  38         unsigned long eflags;
  39         unsigned long esp;
  40         unsigned long ss;
  41 };
  42
  43 void free_pagetables(void);
  44 int init_pagetables(struct page **switcher_page, unsigned int pages);
  45
  46 /* Full 4G segment descriptors, suitable for CS and DS. */
  47 #define FULL_EXEC_SEGMENT ((struct desc_struct){0x0000ffff, 0x00cf9b00})
  48 #define FULL_SEGMENT ((struct desc_struct){0x0000ffff, 0x00cf9300})
  49
  50 struct lguest_dma_info
  51 {
  52         struct list_head list;
  53         union futex_key key;
  54         unsigned long dmas;
  55         u16 next_dma;
  56         u16 num_dmas;
  57         u16 guestid;
  58         u8 interrupt;   /* 0 when not registered */
  59 };
  60
  61 /* We have separate types for the guest's ptes & pgds and the shadow ptes &
  62  * pgds.  Since this host might use three-level pagetables and the guest and
  63  * shadow pagetables don't, we can't use the normal pte_t/pgd_t. */
  64 typedef union {
  65         struct { unsigned flags:12, pfn:20; };
  66         struct { unsigned long val; } raw;
  67 } spgd_t;
  68 typedef union {
  69         struct { unsigned flags:12, pfn:20; };
  70         struct { unsigned long val; } raw;
  71 } spte_t;
  72 typedef union {
  73         struct { unsigned flags:12, pfn:20; };
  74         struct { unsigned long val; } raw;
  75 } gpgd_t;
  76 typedef union {
  77         struct { unsigned flags:12, pfn:20; };
  78         struct { unsigned long val; } raw;
  79 } gpte_t;
  80 #define mkgpte(_val) ((gpte_t){.raw.val = _val})
  81 #define mkgpgd(_val) ((gpgd_t){.raw.val = _val})
  82
  83 struct pgdir
  84 {
  85         unsigned long cr3;
  86         spgd_t *pgdir;
  87 };
  88
  89 /* This is a guest-specific page (mapped ro) into the guest. */
  90 struct lguest_ro_state
  91 {
  92         /* Host information we need to restore when we switch back. */
  93         u32 host_cr3;
  94         struct Xgt_desc_struct host_idt_desc;
  95         struct Xgt_desc_struct host_gdt_desc;
  96         u32 host_sp;
  97
  98         /* Fields which are used when guest is running. */
  99         struct Xgt_desc_struct guest_idt_desc;
 100         struct Xgt_desc_struct guest_gdt_desc;
 101         struct i386_hw_tss guest_tss;
 102         struct desc_struct guest_idt[IDT_ENTRIES];
 103         struct desc_struct guest_gdt[GDT_ENTRIES];
 104 };
 105
 106 /* We have two pages shared with guests, per cpu.  */
 107 struct lguest_pages
 108 {
 109         /* This is the stack page mapped rw in guest */
 110         char spare[PAGE_SIZE - sizeof(struct lguest_regs)];
 111         struct lguest_regs regs;
 112
 113         /* This is the host state & guest descriptor page, ro in guest */
 114         struct lguest_ro_state state;
 115 } __attribute__((aligned(PAGE_SIZE)));
 116
 117 #define CHANGED_IDT             1
 118 #define CHANGED_GDT             2
 119 #define CHANGED_GDT_TLS         4 /* Actually a subset of CHANGED_GDT */
 120 #define CHANGED_ALL             3
 121
 122 /* The private info the thread maintains about the guest. */
 123 struct lguest
 124 {
 125         /* At end of a page shared mapped over lguest_pages in guest.  */
 126         unsigned long regs_page;
 127         struct lguest_regs *regs;
 128         struct lguest_data __user *lguest_data;
 129         struct task_struct *tsk;
 130         struct mm_struct *mm;   /* == tsk->mm, but that becomes NULL on exit */
 131         u16 guestid;
 132         u32 pfn_limit;
 133         u32 page_offset;
 134         u32 cr2;
 135         int halted;
 136         int ts;
 137         u32 next_hcall;
 138         u32 esp1;
 139         u8 ss1;
 140
 141         /* Do we need to stop what we're doing and return to userspace? */
 142         int break_out;
 143         wait_queue_head_t break_wq;
 144
 145         /* Bitmap of what has changed: see CHANGED_* above. */
 146         int changed;
 147         struct lguest_pages *last_pages;
 148
 149         /* We keep a small number of these. */
 150         u32 pgdidx;
 151         struct pgdir pgdirs[4];
 152
 153         /* Cached wakeup: we hold a reference to this task. */
 154         struct task_struct *wake;
 155
 156         unsigned long noirq_start, noirq_end;
 157         int dma_is_pending;
 158         unsigned long pending_dma; /* struct lguest_dma */
 159         unsigned long pending_key; /* address they're sending to */
 160
 161         unsigned int stack_pages;
 162         u32 tsc_khz;
 163
 164         struct lguest_dma_info dma[LGUEST_MAX_DMA];
 165
 166         /* Dead? */
 167         const char *dead;
 168
 169         /* The GDT entries copied into lguest_ro_state when running. */
 170         struct desc_struct gdt[GDT_ENTRIES];
 171
 172         /* The IDT entries: some copied into lguest_ro_state when running. */
 173         struct desc_struct idt[FIRST_EXTERNAL_VECTOR+LGUEST_IRQS];
 174         struct desc_struct syscall_idt;
 175
 176         /* Virtual clock device */
 177         struct hrtimer hrt;
 178
 179         /* Pending virtual interrupts */
 180         DECLARE_BITMAP(irqs_pending, LGUEST_IRQS);
 181 };
 182
 183 extern struct lguest lguests[];
 184 extern struct mutex lguest_lock;
 185
 186 /* core.c: */
 187 u32 lgread_u32(struct lguest *lg, unsigned long addr);
 188 void lgwrite_u32(struct lguest *lg, unsigned long addr, u32 val);
 189 void lgread(struct lguest *lg, void *buf, unsigned long addr, unsigned len);
 190 void lgwrite(struct lguest *lg, unsigned long, const void *buf, unsigned len);
 191 int find_free_guest(void);
 192 int lguest_address_ok(const struct lguest *lg,
 193                       unsigned long addr, unsigned long len);
 194 int run_guest(struct lguest *lg, unsigned long __user *user);
 195
 196
 197 /* interrupts_and_traps.c: */
 198 void maybe_do_interrupt(struct lguest *lg);
 199 int deliver_trap(struct lguest *lg, unsigned int num);
 200 void load_guest_idt_entry(struct lguest *lg, unsigned int i, u32 low, u32 hi);
 201 void guest_set_stack(struct lguest *lg, u32 seg, u32 esp, unsigned int pages);
 202 void pin_stack_pages(struct lguest *lg);
 203 void setup_default_idt_entries(struct lguest_ro_state *state,
 204                                const unsigned long *def);
 205 void copy_traps(const struct lguest *lg, struct desc_struct *idt,
 206                 const unsigned long *def);
 207 void guest_set_clockevent(struct lguest *lg, unsigned long delta);
 208 void init_clockdev(struct lguest *lg);
 209
 210 /* segments.c: */
 211 void setup_default_gdt_entries(struct lguest_ro_state *state);
 212 void setup_guest_gdt(struct lguest *lg);
 213 void load_guest_gdt(struct lguest *lg, unsigned long table, u32 num);
 214 void guest_load_tls(struct lguest *lg, unsigned long tls_array);
 215 void copy_gdt(const struct lguest *lg, struct desc_struct *gdt);
 216 void copy_gdt_tls(const struct lguest *lg, struct desc_struct *gdt);
 217
 218 /* page_tables.c: */
 219 int init_guest_pagetable(struct lguest *lg, unsigned long pgtable);
 220 void free_guest_pagetable(struct lguest *lg);
 221 void guest_new_pagetable(struct lguest *lg, unsigned long pgtable);
 222 void guest_set_pmd(struct lguest *lg, unsigned long cr3, u32 i);
 223 void guest_pagetable_clear_all(struct lguest *lg);
 224 void guest_pagetable_flush_user(struct lguest *lg);
 225 void guest_set_pte(struct lguest *lg, unsigned long cr3,
 226                    unsigned long vaddr, gpte_t val);
 227 void map_switcher_in_guest(struct lguest *lg, struct lguest_pages *pages);
 228 int demand_page(struct lguest *info, unsigned long cr2, int errcode);
 229 void pin_page(struct lguest *lg, unsigned long vaddr);
 230
 231 /* lguest_user.c: */
 232 int lguest_device_init(void);
 233 void lguest_device_remove(void);
 234
 235 /* io.c: */
 236 void lguest_io_init(void);
 237 int bind_dma(struct lguest *lg,
 238              unsigned long key, unsigned long udma, u16 numdmas, u8 interrupt);
 239 void send_dma(struct lguest *info, unsigned long key, unsigned long udma);
 240 void release_all_dma(struct lguest *lg);
 241 unsigned long get_dma_buffer(struct lguest *lg, unsigned long key,
 242                              unsigned long *interrupt);
 243
 244 /* hypercalls.c: */
 245 void do_hypercalls(struct lguest *lg);
 246
 247 /*L:035
 248  * Let's step aside for the moment, to study one important routine that's used
 249  * widely in the Host code.
 250  *
 251  * There are many cases where the Guest does something invalid, like pass crap
 252  * to a hypercall.  Since only the Guest kernel can make hypercalls, it's quite
 253  * acceptable to simply terminate the Guest and give the Launcher a nicely
 254  * formatted reason.  It's also simpler for the Guest itself, which doesn't
 255  * need to check most hypercalls for "success"; if you're still running, it
 256  * succeeded.
 257  *
 258  * Once this is called, the Guest will never run again, so most Host code can
 259  * call this then continue as if nothing had happened.  This means many
 260  * functions don't have to explicitly return an error code, which keeps the
 261  * code simple.
 262  *
 263  * It also means that this can be called more than once: only the first one is
 264  * remembered.  The only trick is that we still need to kill the Guest even if
 265  * we can't allocate memory to store the reason.  Linux has a neat way of
 266  * packing error codes into invalid pointers, so we use that here.
 267  *
 268  * Like any macro which uses an "if", it is safely wrapped in a run-once "do {
 269  * } while(0)".
 270  */
 271 #define kill_guest(lg, fmt...)                                  \
 272 do {                                                            \
 273         if (!(lg)->dead) {                                      \
 274                 (lg)->dead = kasprintf(GFP_ATOMIC, fmt);        \
 275                 if (!(lg)->dead)                                \
 276                         (lg)->dead = ERR_PTR(-ENOMEM);          \
 277         }                                                       \
 278 } while(0)
 279 /* (End of aside) :*/
 280
 281 static inline unsigned long guest_pa(struct lguest *lg, unsigned long vaddr)
 282 {
 283         return vaddr - lg->page_offset;
 284 }
 285 #endif  /* __ASSEMBLY__ */
 286 #endif  /* _LGUEST_H */