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 /*H:310 The page-table code owes a great debt of gratitude to Andi Kleen.  He
  62  * reviewed the original code which used "u32" for all page table entries, and
  63  * insisted that it would be far clearer with explicit typing.  I thought it
  64  * was overkill, but he was right: it is much clearer than it was before.
  65  *
  66  * We have separate types for the Guest's ptes & pgds and the shadow ptes &
  67  * pgds.  There's already a Linux type for these (pte_t and pgd_t) but they
  68  * change depending on kernel config options (PAE). */
  69
  70 /* Each entry is identical: lower 12 bits of flags and upper 20 bits for the
  71  * "page frame number" (0 == first physical page, etc).  They are different
  72  * types so the compiler will warn us if we mix them improperly. */
  73 typedef union {
  74         struct { unsigned flags:12, pfn:20; };
  75         struct { unsigned long val; } raw;
  76 } spgd_t;
  77 typedef union {
  78         struct { unsigned flags:12, pfn:20; };
  79         struct { unsigned long val; } raw;
  80 } spte_t;
  81 typedef union {
  82         struct { unsigned flags:12, pfn:20; };
  83         struct { unsigned long val; } raw;
  84 } gpgd_t;
  85 typedef union {
  86         struct { unsigned flags:12, pfn:20; };
  87         struct { unsigned long val; } raw;
  88 } gpte_t;
  89
  90 /* We have two convenient macros to convert a "raw" value as handed to us by
  91  * the Guest into the correct Guest PGD or PTE type. */
  92 #define mkgpte(_val) ((gpte_t){.raw.val = _val})
  93 #define mkgpgd(_val) ((gpgd_t){.raw.val = _val})
  94 /*:*/
  95
  96 struct pgdir
  97 {
  98         unsigned long cr3;
  99         spgd_t *pgdir;
 100 };
 101
 102 /* This is a guest-specific page (mapped ro) into the guest. */
 103 struct lguest_ro_state
 104 {
 105         /* Host information we need to restore when we switch back. */
 106         u32 host_cr3;
 107         struct Xgt_desc_struct host_idt_desc;
 108         struct Xgt_desc_struct host_gdt_desc;
 109         u32 host_sp;
 110
 111         /* Fields which are used when guest is running. */
 112         struct Xgt_desc_struct guest_idt_desc;
 113         struct Xgt_desc_struct guest_gdt_desc;
 114         struct i386_hw_tss guest_tss;
 115         struct desc_struct guest_idt[IDT_ENTRIES];
 116         struct desc_struct guest_gdt[GDT_ENTRIES];
 117 };
 118
 119 /* We have two pages shared with guests, per cpu.  */
 120 struct lguest_pages
 121 {
 122         /* This is the stack page mapped rw in guest */
 123         char spare[PAGE_SIZE - sizeof(struct lguest_regs)];
 124         struct lguest_regs regs;
 125
 126         /* This is the host state & guest descriptor page, ro in guest */
 127         struct lguest_ro_state state;
 128 } __attribute__((aligned(PAGE_SIZE)));
 129
 130 #define CHANGED_IDT             1
 131 #define CHANGED_GDT             2
 132 #define CHANGED_GDT_TLS         4 /* Actually a subset of CHANGED_GDT */
 133 #define CHANGED_ALL             3
 134
 135 /* The private info the thread maintains about the guest. */
 136 struct lguest
 137 {
 138         /* At end of a page shared mapped over lguest_pages in guest.  */
 139         unsigned long regs_page;
 140         struct lguest_regs *regs;
 141         struct lguest_data __user *lguest_data;
 142         struct task_struct *tsk;
 143         struct mm_struct *mm;   /* == tsk->mm, but that becomes NULL on exit */
 144         u16 guestid;
 145         u32 pfn_limit;
 146         u32 page_offset;
 147         u32 cr2;
 148         int halted;
 149         int ts;
 150         u32 next_hcall;
 151         u32 esp1;
 152         u8 ss1;
 153
 154         /* Do we need to stop what we're doing and return to userspace? */
 155         int break_out;
 156         wait_queue_head_t break_wq;
 157
 158         /* Bitmap of what has changed: see CHANGED_* above. */
 159         int changed;
 160         struct lguest_pages *last_pages;
 161
 162         /* We keep a small number of these. */
 163         u32 pgdidx;
 164         struct pgdir pgdirs[4];
 165
 166         /* Cached wakeup: we hold a reference to this task. */
 167         struct task_struct *wake;
 168
 169         unsigned long noirq_start, noirq_end;
 170         int dma_is_pending;
 171         unsigned long pending_dma; /* struct lguest_dma */
 172         unsigned long pending_key; /* address they're sending to */
 173
 174         unsigned int stack_pages;
 175         u32 tsc_khz;
 176
 177         struct lguest_dma_info dma[LGUEST_MAX_DMA];
 178
 179         /* Dead? */
 180         const char *dead;
 181
 182         /* The GDT entries copied into lguest_ro_state when running. */
 183         struct desc_struct gdt[GDT_ENTRIES];
 184
 185         /* The IDT entries: some copied into lguest_ro_state when running. */
 186         struct desc_struct idt[FIRST_EXTERNAL_VECTOR+LGUEST_IRQS];
 187         struct desc_struct syscall_idt;
 188
 189         /* Virtual clock device */
 190         struct hrtimer hrt;
 191
 192         /* Pending virtual interrupts */
 193         DECLARE_BITMAP(irqs_pending, LGUEST_IRQS);
 194 };
 195
 196 extern struct lguest lguests[];
 197 extern struct mutex lguest_lock;
 198
 199 /* core.c: */
 200 u32 lgread_u32(struct lguest *lg, unsigned long addr);
 201 void lgwrite_u32(struct lguest *lg, unsigned long addr, u32 val);
 202 void lgread(struct lguest *lg, void *buf, unsigned long addr, unsigned len);
 203 void lgwrite(struct lguest *lg, unsigned long, const void *buf, unsigned len);
 204 int find_free_guest(void);
 205 int lguest_address_ok(const struct lguest *lg,
 206                       unsigned long addr, unsigned long len);
 207 int run_guest(struct lguest *lg, unsigned long __user *user);
 208
 209
 210 /* interrupts_and_traps.c: */
 211 void maybe_do_interrupt(struct lguest *lg);
 212 int deliver_trap(struct lguest *lg, unsigned int num);
 213 void load_guest_idt_entry(struct lguest *lg, unsigned int i, u32 low, u32 hi);
 214 void guest_set_stack(struct lguest *lg, u32 seg, u32 esp, unsigned int pages);
 215 void pin_stack_pages(struct lguest *lg);
 216 void setup_default_idt_entries(struct lguest_ro_state *state,
 217                                const unsigned long *def);
 218 void copy_traps(const struct lguest *lg, struct desc_struct *idt,
 219                 const unsigned long *def);
 220 void guest_set_clockevent(struct lguest *lg, unsigned long delta);
 221 void init_clockdev(struct lguest *lg);
 222
 223 /* segments.c: */
 224 void setup_default_gdt_entries(struct lguest_ro_state *state);
 225 void setup_guest_gdt(struct lguest *lg);
 226 void load_guest_gdt(struct lguest *lg, unsigned long table, u32 num);
 227 void guest_load_tls(struct lguest *lg, unsigned long tls_array);
 228 void copy_gdt(const struct lguest *lg, struct desc_struct *gdt);
 229 void copy_gdt_tls(const struct lguest *lg, struct desc_struct *gdt);
 230
 231 /* page_tables.c: */
 232 int init_guest_pagetable(struct lguest *lg, unsigned long pgtable);
 233 void free_guest_pagetable(struct lguest *lg);
 234 void guest_new_pagetable(struct lguest *lg, unsigned long pgtable);
 235 void guest_set_pmd(struct lguest *lg, unsigned long cr3, u32 i);
 236 void guest_pagetable_clear_all(struct lguest *lg);
 237 void guest_pagetable_flush_user(struct lguest *lg);
 238 void guest_set_pte(struct lguest *lg, unsigned long cr3,
 239                    unsigned long vaddr, gpte_t val);
 240 void map_switcher_in_guest(struct lguest *lg, struct lguest_pages *pages);
 241 int demand_page(struct lguest *info, unsigned long cr2, int errcode);
 242 void pin_page(struct lguest *lg, unsigned long vaddr);
 243
 244 /* lguest_user.c: */
 245 int lguest_device_init(void);
 246 void lguest_device_remove(void);
 247
 248 /* io.c: */
 249 void lguest_io_init(void);
 250 int bind_dma(struct lguest *lg,
 251              unsigned long key, unsigned long udma, u16 numdmas, u8 interrupt);
 252 void send_dma(struct lguest *info, unsigned long key, unsigned long udma);
 253 void release_all_dma(struct lguest *lg);
 254 unsigned long get_dma_buffer(struct lguest *lg, unsigned long key,
 255                              unsigned long *interrupt);
 256
 257 /* hypercalls.c: */
 258 void do_hypercalls(struct lguest *lg);
 259 void write_timestamp(struct lguest *lg);
 260
 261 /*L:035
 262  * Let's step aside for the moment, to study one important routine that's used
 263  * widely in the Host code.
 264  *
 265  * There are many cases where the Guest does something invalid, like pass crap
 266  * to a hypercall.  Since only the Guest kernel can make hypercalls, it's quite
 267  * acceptable to simply terminate the Guest and give the Launcher a nicely
 268  * formatted reason.  It's also simpler for the Guest itself, which doesn't
 269  * need to check most hypercalls for "success"; if you're still running, it
 270  * succeeded.
 271  *
 272  * Once this is called, the Guest will never run again, so most Host code can
 273  * call this then continue as if nothing had happened.  This means many
 274  * functions don't have to explicitly return an error code, which keeps the
 275  * code simple.
 276  *
 277  * It also means that this can be called more than once: only the first one is
 278  * remembered.  The only trick is that we still need to kill the Guest even if
 279  * we can't allocate memory to store the reason.  Linux has a neat way of
 280  * packing error codes into invalid pointers, so we use that here.
 281  *
 282  * Like any macro which uses an "if", it is safely wrapped in a run-once "do {
 283  * } while(0)".
 284  */
 285 #define kill_guest(lg, fmt...)                                  \
 286 do {                                                            \
 287         if (!(lg)->dead) {                                      \
 288                 (lg)->dead = kasprintf(GFP_ATOMIC, fmt);        \
 289                 if (!(lg)->dead)                                \
 290                         (lg)->dead = ERR_PTR(-ENOMEM);          \
 291         }                                                       \
 292 } while(0)
 293 /* (End of aside) :*/
 294
 295 static inline unsigned long guest_pa(struct lguest *lg, unsigned long vaddr)
 296 {
 297         return vaddr - lg->page_offset;
 298 }
 299 #endif  /* __ASSEMBLY__ */
 300 #endif  /* _LGUEST_H */