xref: /openbmc/qemu/include/exec/exec-all.h (revision 6620801f)
1 /*
2  * internal execution defines for qemu
3  *
4  *  Copyright (c) 2003 Fabrice Bellard
5  *
6  * This library is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2 of the License, or (at your option) any later version.
10  *
11  * This library is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #ifndef EXEC_ALL_H
21 #define EXEC_ALL_H
22 
23 #include "cpu.h"
24 #include "exec/tb-context.h"
25 #ifdef CONFIG_TCG
26 #include "exec/cpu_ldst.h"
27 #endif
28 #include "sysemu/cpus.h"
29 
30 /* allow to see translation results - the slowdown should be negligible, so we leave it */
31 #define DEBUG_DISAS
32 
33 /* Page tracking code uses ram addresses in system mode, and virtual
34    addresses in userspace mode.  Define tb_page_addr_t to be an appropriate
35    type.  */
36 #if defined(CONFIG_USER_ONLY)
37 typedef abi_ulong tb_page_addr_t;
38 #define TB_PAGE_ADDR_FMT TARGET_ABI_FMT_lx
39 #else
40 typedef ram_addr_t tb_page_addr_t;
41 #define TB_PAGE_ADDR_FMT RAM_ADDR_FMT
42 #endif
43 
44 #include "qemu/log.h"
45 
46 void gen_intermediate_code(CPUState *cpu, TranslationBlock *tb, int max_insns);
47 void restore_state_to_opc(CPUArchState *env, TranslationBlock *tb,
48                           target_ulong *data);
49 
50 void cpu_gen_init(void);
51 
52 /**
53  * cpu_restore_state:
54  * @cpu: the vCPU state is to be restore to
55  * @searched_pc: the host PC the fault occurred at
56  * @will_exit: true if the TB executed will be interrupted after some
57                cpu adjustments. Required for maintaining the correct
58                icount valus
59  * @return: true if state was restored, false otherwise
60  *
61  * Attempt to restore the state for a fault occurring in translated
62  * code. If the searched_pc is not in translated code no state is
63  * restored and the function returns false.
64  */
65 bool cpu_restore_state(CPUState *cpu, uintptr_t searched_pc, bool will_exit);
66 
67 void QEMU_NORETURN cpu_loop_exit_noexc(CPUState *cpu);
68 void QEMU_NORETURN cpu_io_recompile(CPUState *cpu, uintptr_t retaddr);
69 TranslationBlock *tb_gen_code(CPUState *cpu,
70                               target_ulong pc, target_ulong cs_base,
71                               uint32_t flags,
72                               int cflags);
73 
74 void QEMU_NORETURN cpu_loop_exit(CPUState *cpu);
75 void QEMU_NORETURN cpu_loop_exit_restore(CPUState *cpu, uintptr_t pc);
76 void QEMU_NORETURN cpu_loop_exit_atomic(CPUState *cpu, uintptr_t pc);
77 
78 /**
79  * cpu_loop_exit_requested:
80  * @cpu: The CPU state to be tested
81  *
82  * Indicate if somebody asked for a return of the CPU to the main loop
83  * (e.g., via cpu_exit() or cpu_interrupt()).
84  *
85  * This is helpful for architectures that support interruptible
86  * instructions. After writing back all state to registers/memory, this
87  * call can be used to check if it makes sense to return to the main loop
88  * or to continue executing the interruptible instruction.
89  */
90 static inline bool cpu_loop_exit_requested(CPUState *cpu)
91 {
92     return (int32_t)atomic_read(&cpu_neg(cpu)->icount_decr.u32) < 0;
93 }
94 
95 #if !defined(CONFIG_USER_ONLY)
96 void cpu_reloading_memory_map(void);
97 /**
98  * cpu_address_space_init:
99  * @cpu: CPU to add this address space to
100  * @asidx: integer index of this address space
101  * @prefix: prefix to be used as name of address space
102  * @mr: the root memory region of address space
103  *
104  * Add the specified address space to the CPU's cpu_ases list.
105  * The address space added with @asidx 0 is the one used for the
106  * convenience pointer cpu->as.
107  * The target-specific code which registers ASes is responsible
108  * for defining what semantics address space 0, 1, 2, etc have.
109  *
110  * Before the first call to this function, the caller must set
111  * cpu->num_ases to the total number of address spaces it needs
112  * to support.
113  *
114  * Note that with KVM only one address space is supported.
115  */
116 void cpu_address_space_init(CPUState *cpu, int asidx,
117                             const char *prefix, MemoryRegion *mr);
118 #endif
119 
120 #if !defined(CONFIG_USER_ONLY) && defined(CONFIG_TCG)
121 /* cputlb.c */
122 /**
123  * tlb_init - initialize a CPU's TLB
124  * @cpu: CPU whose TLB should be initialized
125  */
126 void tlb_init(CPUState *cpu);
127 /**
128  * tlb_flush_page:
129  * @cpu: CPU whose TLB should be flushed
130  * @addr: virtual address of page to be flushed
131  *
132  * Flush one page from the TLB of the specified CPU, for all
133  * MMU indexes.
134  */
135 void tlb_flush_page(CPUState *cpu, target_ulong addr);
136 /**
137  * tlb_flush_page_all_cpus:
138  * @cpu: src CPU of the flush
139  * @addr: virtual address of page to be flushed
140  *
141  * Flush one page from the TLB of the specified CPU, for all
142  * MMU indexes.
143  */
144 void tlb_flush_page_all_cpus(CPUState *src, target_ulong addr);
145 /**
146  * tlb_flush_page_all_cpus_synced:
147  * @cpu: src CPU of the flush
148  * @addr: virtual address of page to be flushed
149  *
150  * Flush one page from the TLB of the specified CPU, for all MMU
151  * indexes like tlb_flush_page_all_cpus except the source vCPUs work
152  * is scheduled as safe work meaning all flushes will be complete once
153  * the source vCPUs safe work is complete. This will depend on when
154  * the guests translation ends the TB.
155  */
156 void tlb_flush_page_all_cpus_synced(CPUState *src, target_ulong addr);
157 /**
158  * tlb_flush:
159  * @cpu: CPU whose TLB should be flushed
160  *
161  * Flush the entire TLB for the specified CPU. Most CPU architectures
162  * allow the implementation to drop entries from the TLB at any time
163  * so this is generally safe. If more selective flushing is required
164  * use one of the other functions for efficiency.
165  */
166 void tlb_flush(CPUState *cpu);
167 /**
168  * tlb_flush_all_cpus:
169  * @cpu: src CPU of the flush
170  */
171 void tlb_flush_all_cpus(CPUState *src_cpu);
172 /**
173  * tlb_flush_all_cpus_synced:
174  * @cpu: src CPU of the flush
175  *
176  * Like tlb_flush_all_cpus except this except the source vCPUs work is
177  * scheduled as safe work meaning all flushes will be complete once
178  * the source vCPUs safe work is complete. This will depend on when
179  * the guests translation ends the TB.
180  */
181 void tlb_flush_all_cpus_synced(CPUState *src_cpu);
182 /**
183  * tlb_flush_page_by_mmuidx:
184  * @cpu: CPU whose TLB should be flushed
185  * @addr: virtual address of page to be flushed
186  * @idxmap: bitmap of MMU indexes to flush
187  *
188  * Flush one page from the TLB of the specified CPU, for the specified
189  * MMU indexes.
190  */
191 void tlb_flush_page_by_mmuidx(CPUState *cpu, target_ulong addr,
192                               uint16_t idxmap);
193 /**
194  * tlb_flush_page_by_mmuidx_all_cpus:
195  * @cpu: Originating CPU of the flush
196  * @addr: virtual address of page to be flushed
197  * @idxmap: bitmap of MMU indexes to flush
198  *
199  * Flush one page from the TLB of all CPUs, for the specified
200  * MMU indexes.
201  */
202 void tlb_flush_page_by_mmuidx_all_cpus(CPUState *cpu, target_ulong addr,
203                                        uint16_t idxmap);
204 /**
205  * tlb_flush_page_by_mmuidx_all_cpus_synced:
206  * @cpu: Originating CPU of the flush
207  * @addr: virtual address of page to be flushed
208  * @idxmap: bitmap of MMU indexes to flush
209  *
210  * Flush one page from the TLB of all CPUs, for the specified MMU
211  * indexes like tlb_flush_page_by_mmuidx_all_cpus except the source
212  * vCPUs work is scheduled as safe work meaning all flushes will be
213  * complete once  the source vCPUs safe work is complete. This will
214  * depend on when the guests translation ends the TB.
215  */
216 void tlb_flush_page_by_mmuidx_all_cpus_synced(CPUState *cpu, target_ulong addr,
217                                               uint16_t idxmap);
218 /**
219  * tlb_flush_by_mmuidx:
220  * @cpu: CPU whose TLB should be flushed
221  * @wait: If true ensure synchronisation by exiting the cpu_loop
222  * @idxmap: bitmap of MMU indexes to flush
223  *
224  * Flush all entries from the TLB of the specified CPU, for the specified
225  * MMU indexes.
226  */
227 void tlb_flush_by_mmuidx(CPUState *cpu, uint16_t idxmap);
228 /**
229  * tlb_flush_by_mmuidx_all_cpus:
230  * @cpu: Originating CPU of the flush
231  * @idxmap: bitmap of MMU indexes to flush
232  *
233  * Flush all entries from all TLBs of all CPUs, for the specified
234  * MMU indexes.
235  */
236 void tlb_flush_by_mmuidx_all_cpus(CPUState *cpu, uint16_t idxmap);
237 /**
238  * tlb_flush_by_mmuidx_all_cpus_synced:
239  * @cpu: Originating CPU of the flush
240  * @idxmap: bitmap of MMU indexes to flush
241  *
242  * Flush all entries from all TLBs of all CPUs, for the specified
243  * MMU indexes like tlb_flush_by_mmuidx_all_cpus except except the source
244  * vCPUs work is scheduled as safe work meaning all flushes will be
245  * complete once  the source vCPUs safe work is complete. This will
246  * depend on when the guests translation ends the TB.
247  */
248 void tlb_flush_by_mmuidx_all_cpus_synced(CPUState *cpu, uint16_t idxmap);
249 /**
250  * tlb_set_page_with_attrs:
251  * @cpu: CPU to add this TLB entry for
252  * @vaddr: virtual address of page to add entry for
253  * @paddr: physical address of the page
254  * @attrs: memory transaction attributes
255  * @prot: access permissions (PAGE_READ/PAGE_WRITE/PAGE_EXEC bits)
256  * @mmu_idx: MMU index to insert TLB entry for
257  * @size: size of the page in bytes
258  *
259  * Add an entry to this CPU's TLB (a mapping from virtual address
260  * @vaddr to physical address @paddr) with the specified memory
261  * transaction attributes. This is generally called by the target CPU
262  * specific code after it has been called through the tlb_fill()
263  * entry point and performed a successful page table walk to find
264  * the physical address and attributes for the virtual address
265  * which provoked the TLB miss.
266  *
267  * At most one entry for a given virtual address is permitted. Only a
268  * single TARGET_PAGE_SIZE region is mapped; the supplied @size is only
269  * used by tlb_flush_page.
270  */
271 void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr,
272                              hwaddr paddr, MemTxAttrs attrs,
273                              int prot, int mmu_idx, target_ulong size);
274 /* tlb_set_page:
275  *
276  * This function is equivalent to calling tlb_set_page_with_attrs()
277  * with an @attrs argument of MEMTXATTRS_UNSPECIFIED. It's provided
278  * as a convenience for CPUs which don't use memory transaction attributes.
279  */
280 void tlb_set_page(CPUState *cpu, target_ulong vaddr,
281                   hwaddr paddr, int prot,
282                   int mmu_idx, target_ulong size);
283 #else
284 static inline void tlb_init(CPUState *cpu)
285 {
286 }
287 static inline void tlb_flush_page(CPUState *cpu, target_ulong addr)
288 {
289 }
290 static inline void tlb_flush_page_all_cpus(CPUState *src, target_ulong addr)
291 {
292 }
293 static inline void tlb_flush_page_all_cpus_synced(CPUState *src,
294                                                   target_ulong addr)
295 {
296 }
297 static inline void tlb_flush(CPUState *cpu)
298 {
299 }
300 static inline void tlb_flush_all_cpus(CPUState *src_cpu)
301 {
302 }
303 static inline void tlb_flush_all_cpus_synced(CPUState *src_cpu)
304 {
305 }
306 static inline void tlb_flush_page_by_mmuidx(CPUState *cpu,
307                                             target_ulong addr, uint16_t idxmap)
308 {
309 }
310 
311 static inline void tlb_flush_by_mmuidx(CPUState *cpu, uint16_t idxmap)
312 {
313 }
314 static inline void tlb_flush_page_by_mmuidx_all_cpus(CPUState *cpu,
315                                                      target_ulong addr,
316                                                      uint16_t idxmap)
317 {
318 }
319 static inline void tlb_flush_page_by_mmuidx_all_cpus_synced(CPUState *cpu,
320                                                             target_ulong addr,
321                                                             uint16_t idxmap)
322 {
323 }
324 static inline void tlb_flush_by_mmuidx_all_cpus(CPUState *cpu, uint16_t idxmap)
325 {
326 }
327 
328 static inline void tlb_flush_by_mmuidx_all_cpus_synced(CPUState *cpu,
329                                                        uint16_t idxmap)
330 {
331 }
332 #endif
333 void *probe_access(CPUArchState *env, target_ulong addr, int size,
334                    MMUAccessType access_type, int mmu_idx, uintptr_t retaddr);
335 
336 static inline void *probe_write(CPUArchState *env, target_ulong addr, int size,
337                                 int mmu_idx, uintptr_t retaddr)
338 {
339     return probe_access(env, addr, size, MMU_DATA_STORE, mmu_idx, retaddr);
340 }
341 
342 static inline void *probe_read(CPUArchState *env, target_ulong addr, int size,
343                                int mmu_idx, uintptr_t retaddr)
344 {
345     return probe_access(env, addr, size, MMU_DATA_LOAD, mmu_idx, retaddr);
346 }
347 
348 #define CODE_GEN_ALIGN           16 /* must be >= of the size of a icache line */
349 
350 /* Estimated block size for TB allocation.  */
351 /* ??? The following is based on a 2015 survey of x86_64 host output.
352    Better would seem to be some sort of dynamically sized TB array,
353    adapting to the block sizes actually being produced.  */
354 #if defined(CONFIG_SOFTMMU)
355 #define CODE_GEN_AVG_BLOCK_SIZE 400
356 #else
357 #define CODE_GEN_AVG_BLOCK_SIZE 150
358 #endif
359 
360 /*
361  * Translation Cache-related fields of a TB.
362  * This struct exists just for convenience; we keep track of TB's in a binary
363  * search tree, and the only fields needed to compare TB's in the tree are
364  * @ptr and @size.
365  * Note: the address of search data can be obtained by adding @size to @ptr.
366  */
367 struct tb_tc {
368     void *ptr;    /* pointer to the translated code */
369     size_t size;
370 };
371 
372 struct TranslationBlock {
373     target_ulong pc;   /* simulated PC corresponding to this block (EIP + CS base) */
374     target_ulong cs_base; /* CS base for this block */
375     uint32_t flags; /* flags defining in which context the code was generated */
376     uint16_t size;      /* size of target code for this block (1 <=
377                            size <= TARGET_PAGE_SIZE) */
378     uint16_t icount;
379     uint32_t cflags;    /* compile flags */
380 #define CF_COUNT_MASK  0x00007fff
381 #define CF_LAST_IO     0x00008000 /* Last insn may be an IO access.  */
382 #define CF_NOCACHE     0x00010000 /* To be freed after execution */
383 #define CF_USE_ICOUNT  0x00020000
384 #define CF_INVALID     0x00040000 /* TB is stale. Set with @jmp_lock held */
385 #define CF_PARALLEL    0x00080000 /* Generate code for a parallel context */
386 #define CF_CLUSTER_MASK 0xff000000 /* Top 8 bits are cluster ID */
387 #define CF_CLUSTER_SHIFT 24
388 /* cflags' mask for hashing/comparison */
389 #define CF_HASH_MASK   \
390     (CF_COUNT_MASK | CF_LAST_IO | CF_USE_ICOUNT | CF_PARALLEL | CF_CLUSTER_MASK)
391 
392     /* Per-vCPU dynamic tracing state used to generate this TB */
393     uint32_t trace_vcpu_dstate;
394 
395     struct tb_tc tc;
396 
397     /* original tb when cflags has CF_NOCACHE */
398     struct TranslationBlock *orig_tb;
399     /* first and second physical page containing code. The lower bit
400        of the pointer tells the index in page_next[].
401        The list is protected by the TB's page('s) lock(s) */
402     uintptr_t page_next[2];
403     tb_page_addr_t page_addr[2];
404 
405     /* jmp_lock placed here to fill a 4-byte hole. Its documentation is below */
406     QemuSpin jmp_lock;
407 
408     /* The following data are used to directly call another TB from
409      * the code of this one. This can be done either by emitting direct or
410      * indirect native jump instructions. These jumps are reset so that the TB
411      * just continues its execution. The TB can be linked to another one by
412      * setting one of the jump targets (or patching the jump instruction). Only
413      * two of such jumps are supported.
414      */
415     uint16_t jmp_reset_offset[2]; /* offset of original jump target */
416 #define TB_JMP_RESET_OFFSET_INVALID 0xffff /* indicates no jump generated */
417     uintptr_t jmp_target_arg[2];  /* target address or offset */
418 
419     /*
420      * Each TB has a NULL-terminated list (jmp_list_head) of incoming jumps.
421      * Each TB can have two outgoing jumps, and therefore can participate
422      * in two lists. The list entries are kept in jmp_list_next[2]. The least
423      * significant bit (LSB) of the pointers in these lists is used to encode
424      * which of the two list entries is to be used in the pointed TB.
425      *
426      * List traversals are protected by jmp_lock. The destination TB of each
427      * outgoing jump is kept in jmp_dest[] so that the appropriate jmp_lock
428      * can be acquired from any origin TB.
429      *
430      * jmp_dest[] are tagged pointers as well. The LSB is set when the TB is
431      * being invalidated, so that no further outgoing jumps from it can be set.
432      *
433      * jmp_lock also protects the CF_INVALID cflag; a jump must not be chained
434      * to a destination TB that has CF_INVALID set.
435      */
436     uintptr_t jmp_list_head;
437     uintptr_t jmp_list_next[2];
438     uintptr_t jmp_dest[2];
439 };
440 
441 extern bool parallel_cpus;
442 
443 /* Hide the atomic_read to make code a little easier on the eyes */
444 static inline uint32_t tb_cflags(const TranslationBlock *tb)
445 {
446     return atomic_read(&tb->cflags);
447 }
448 
449 /* current cflags for hashing/comparison */
450 static inline uint32_t curr_cflags(void)
451 {
452     return (parallel_cpus ? CF_PARALLEL : 0)
453          | (use_icount ? CF_USE_ICOUNT : 0);
454 }
455 
456 /* TranslationBlock invalidate API */
457 #if defined(CONFIG_USER_ONLY)
458 void tb_invalidate_phys_addr(target_ulong addr);
459 void tb_invalidate_phys_range(target_ulong start, target_ulong end);
460 #else
461 void tb_invalidate_phys_addr(AddressSpace *as, hwaddr addr, MemTxAttrs attrs);
462 #endif
463 void tb_flush(CPUState *cpu);
464 void tb_phys_invalidate(TranslationBlock *tb, tb_page_addr_t page_addr);
465 TranslationBlock *tb_htable_lookup(CPUState *cpu, target_ulong pc,
466                                    target_ulong cs_base, uint32_t flags,
467                                    uint32_t cf_mask);
468 void tb_set_jmp_target(TranslationBlock *tb, int n, uintptr_t addr);
469 
470 /* GETPC is the true target of the return instruction that we'll execute.  */
471 #if defined(CONFIG_TCG_INTERPRETER)
472 extern uintptr_t tci_tb_ptr;
473 # define GETPC() tci_tb_ptr
474 #else
475 # define GETPC() \
476     ((uintptr_t)__builtin_extract_return_addr(__builtin_return_address(0)))
477 #endif
478 
479 /* The true return address will often point to a host insn that is part of
480    the next translated guest insn.  Adjust the address backward to point to
481    the middle of the call insn.  Subtracting one would do the job except for
482    several compressed mode architectures (arm, mips) which set the low bit
483    to indicate the compressed mode; subtracting two works around that.  It
484    is also the case that there are no host isas that contain a call insn
485    smaller than 4 bytes, so we don't worry about special-casing this.  */
486 #define GETPC_ADJ   2
487 
488 #if !defined(CONFIG_USER_ONLY) && defined(CONFIG_DEBUG_TCG)
489 void assert_no_pages_locked(void);
490 #else
491 static inline void assert_no_pages_locked(void)
492 {
493 }
494 #endif
495 
496 #if !defined(CONFIG_USER_ONLY)
497 
498 /**
499  * iotlb_to_section:
500  * @cpu: CPU performing the access
501  * @index: TCG CPU IOTLB entry
502  *
503  * Given a TCG CPU IOTLB entry, return the MemoryRegionSection that
504  * it refers to. @index will have been initially created and returned
505  * by memory_region_section_get_iotlb().
506  */
507 struct MemoryRegionSection *iotlb_to_section(CPUState *cpu,
508                                              hwaddr index, MemTxAttrs attrs);
509 #endif
510 
511 #if defined(CONFIG_USER_ONLY)
512 void mmap_lock(void);
513 void mmap_unlock(void);
514 bool have_mmap_lock(void);
515 
516 /**
517  * get_page_addr_code() - user-mode version
518  * @env: CPUArchState
519  * @addr: guest virtual address of guest code
520  *
521  * Returns @addr.
522  */
523 static inline tb_page_addr_t get_page_addr_code(CPUArchState *env,
524                                                 target_ulong addr)
525 {
526     return addr;
527 }
528 
529 /**
530  * get_page_addr_code_hostp() - user-mode version
531  * @env: CPUArchState
532  * @addr: guest virtual address of guest code
533  *
534  * Returns @addr.
535  *
536  * If @hostp is non-NULL, sets *@hostp to the host address where @addr's content
537  * is kept.
538  */
539 static inline tb_page_addr_t get_page_addr_code_hostp(CPUArchState *env,
540                                                       target_ulong addr,
541                                                       void **hostp)
542 {
543     if (hostp) {
544         *hostp = g2h(addr);
545     }
546     return addr;
547 }
548 #else
549 static inline void mmap_lock(void) {}
550 static inline void mmap_unlock(void) {}
551 
552 /**
553  * get_page_addr_code() - full-system version
554  * @env: CPUArchState
555  * @addr: guest virtual address of guest code
556  *
557  * If we cannot translate and execute from the entire RAM page, or if
558  * the region is not backed by RAM, returns -1. Otherwise, returns the
559  * ram_addr_t corresponding to the guest code at @addr.
560  *
561  * Note: this function can trigger an exception.
562  */
563 tb_page_addr_t get_page_addr_code(CPUArchState *env, target_ulong addr);
564 
565 /**
566  * get_page_addr_code_hostp() - full-system version
567  * @env: CPUArchState
568  * @addr: guest virtual address of guest code
569  *
570  * See get_page_addr_code() (full-system version) for documentation on the
571  * return value.
572  *
573  * Sets *@hostp (when @hostp is non-NULL) as follows.
574  * If the return value is -1, sets *@hostp to NULL. Otherwise, sets *@hostp
575  * to the host address where @addr's content is kept.
576  *
577  * Note: this function can trigger an exception.
578  */
579 tb_page_addr_t get_page_addr_code_hostp(CPUArchState *env, target_ulong addr,
580                                         void **hostp);
581 
582 void tlb_reset_dirty(CPUState *cpu, ram_addr_t start1, ram_addr_t length);
583 void tlb_set_dirty(CPUState *cpu, target_ulong vaddr);
584 
585 /* exec.c */
586 void tb_flush_jmp_cache(CPUState *cpu, target_ulong addr);
587 
588 MemoryRegionSection *
589 address_space_translate_for_iotlb(CPUState *cpu, int asidx, hwaddr addr,
590                                   hwaddr *xlat, hwaddr *plen,
591                                   MemTxAttrs attrs, int *prot);
592 hwaddr memory_region_section_get_iotlb(CPUState *cpu,
593                                        MemoryRegionSection *section);
594 #endif
595 
596 /* vl.c */
597 extern int singlestep;
598 
599 #endif
600