xref: /freebsd/sys/i386/i386/vm86.c (revision a0ee8cc6)
1 /*-
2  * Copyright (c) 1997 Jonathan Lemon
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/priv.h>
33 #include <sys/proc.h>
34 #include <sys/lock.h>
35 #include <sys/malloc.h>
36 #include <sys/mutex.h>
37 
38 #include <vm/vm.h>
39 #include <vm/pmap.h>
40 #include <vm/vm_map.h>
41 #include <vm/vm_page.h>
42 
43 #include <machine/md_var.h>
44 #include <machine/pcb.h>
45 #include <machine/pcb_ext.h>
46 #include <machine/psl.h>
47 #include <machine/specialreg.h>
48 #include <machine/sysarch.h>
49 
50 extern int vm86pa;
51 extern struct pcb *vm86pcb;
52 
53 static struct mtx vm86_lock;
54 
55 extern int vm86_bioscall(struct vm86frame *);
56 extern void vm86_biosret(struct vm86frame *);
57 
58 void vm86_prepcall(struct vm86frame *);
59 
60 struct system_map {
61 	int		type;
62 	vm_offset_t	start;
63 	vm_offset_t	end;
64 };
65 
66 #define	HLT	0xf4
67 #define	CLI	0xfa
68 #define	STI	0xfb
69 #define	PUSHF	0x9c
70 #define	POPF	0x9d
71 #define	INTn	0xcd
72 #define	IRET	0xcf
73 #define	CALLm	0xff
74 #define OPERAND_SIZE_PREFIX	0x66
75 #define ADDRESS_SIZE_PREFIX	0x67
76 #define PUSH_MASK	~(PSL_VM | PSL_RF | PSL_I)
77 #define POP_MASK	~(PSL_VIP | PSL_VIF | PSL_VM | PSL_RF | PSL_IOPL)
78 
79 static __inline caddr_t
80 MAKE_ADDR(u_short sel, u_short off)
81 {
82 	return ((caddr_t)((sel << 4) + off));
83 }
84 
85 static __inline void
86 GET_VEC(u_int vec, u_short *sel, u_short *off)
87 {
88 	*sel = vec >> 16;
89 	*off = vec & 0xffff;
90 }
91 
92 static __inline u_int
93 MAKE_VEC(u_short sel, u_short off)
94 {
95 	return ((sel << 16) | off);
96 }
97 
98 static __inline void
99 PUSH(u_short x, struct vm86frame *vmf)
100 {
101 	vmf->vmf_sp -= 2;
102 	suword16(MAKE_ADDR(vmf->vmf_ss, vmf->vmf_sp), x);
103 }
104 
105 static __inline void
106 PUSHL(u_int x, struct vm86frame *vmf)
107 {
108 	vmf->vmf_sp -= 4;
109 	suword(MAKE_ADDR(vmf->vmf_ss, vmf->vmf_sp), x);
110 }
111 
112 static __inline u_short
113 POP(struct vm86frame *vmf)
114 {
115 	u_short x = fuword16(MAKE_ADDR(vmf->vmf_ss, vmf->vmf_sp));
116 
117 	vmf->vmf_sp += 2;
118 	return (x);
119 }
120 
121 static __inline u_int
122 POPL(struct vm86frame *vmf)
123 {
124 	u_int x = fuword(MAKE_ADDR(vmf->vmf_ss, vmf->vmf_sp));
125 
126 	vmf->vmf_sp += 4;
127 	return (x);
128 }
129 
130 int
131 vm86_emulate(vmf)
132 	struct vm86frame *vmf;
133 {
134 	struct vm86_kernel *vm86;
135 	caddr_t addr;
136 	u_char i_byte;
137 	u_int temp_flags;
138 	int inc_ip = 1;
139 	int retcode = 0;
140 
141 	/*
142 	 * pcb_ext contains the address of the extension area, or zero if
143 	 * the extension is not present.  (This check should not be needed,
144 	 * as we can't enter vm86 mode until we set up an extension area)
145 	 */
146 	if (curpcb->pcb_ext == 0)
147 		return (SIGBUS);
148 	vm86 = &curpcb->pcb_ext->ext_vm86;
149 
150 	if (vmf->vmf_eflags & PSL_T)
151 		retcode = SIGTRAP;
152 
153 	addr = MAKE_ADDR(vmf->vmf_cs, vmf->vmf_ip);
154 	i_byte = fubyte(addr);
155 	if (i_byte == ADDRESS_SIZE_PREFIX) {
156 		i_byte = fubyte(++addr);
157 		inc_ip++;
158 	}
159 
160 	if (vm86->vm86_has_vme) {
161 		switch (i_byte) {
162 		case OPERAND_SIZE_PREFIX:
163 			i_byte = fubyte(++addr);
164 			inc_ip++;
165 			switch (i_byte) {
166 			case PUSHF:
167 				if (vmf->vmf_eflags & PSL_VIF)
168 					PUSHL((vmf->vmf_eflags & PUSH_MASK)
169 					    | PSL_IOPL | PSL_I, vmf);
170 				else
171 					PUSHL((vmf->vmf_eflags & PUSH_MASK)
172 					    | PSL_IOPL, vmf);
173 				vmf->vmf_ip += inc_ip;
174 				return (0);
175 
176 			case POPF:
177 				temp_flags = POPL(vmf) & POP_MASK;
178 				vmf->vmf_eflags = (vmf->vmf_eflags & ~POP_MASK)
179 				    | temp_flags | PSL_VM | PSL_I;
180 				vmf->vmf_ip += inc_ip;
181 				if (temp_flags & PSL_I) {
182 					vmf->vmf_eflags |= PSL_VIF;
183 					if (vmf->vmf_eflags & PSL_VIP)
184 						break;
185 				} else {
186 					vmf->vmf_eflags &= ~PSL_VIF;
187 				}
188 				return (0);
189 			}
190 			break;
191 
192 		/* VME faults here if VIP is set, but does not set VIF. */
193 		case STI:
194 			vmf->vmf_eflags |= PSL_VIF;
195 			vmf->vmf_ip += inc_ip;
196 			if ((vmf->vmf_eflags & PSL_VIP) == 0) {
197 				uprintf("fatal sti\n");
198 				return (SIGKILL);
199 			}
200 			break;
201 
202 		/* VME if no redirection support */
203 		case INTn:
204 			break;
205 
206 		/* VME if trying to set PSL_TF, or PSL_I when VIP is set */
207 		case POPF:
208 			temp_flags = POP(vmf) & POP_MASK;
209 			vmf->vmf_flags = (vmf->vmf_flags & ~POP_MASK)
210 			    | temp_flags | PSL_VM | PSL_I;
211 			vmf->vmf_ip += inc_ip;
212 			if (temp_flags & PSL_I) {
213 				vmf->vmf_eflags |= PSL_VIF;
214 				if (vmf->vmf_eflags & PSL_VIP)
215 					break;
216 			} else {
217 				vmf->vmf_eflags &= ~PSL_VIF;
218 			}
219 			return (retcode);
220 
221 		/* VME if trying to set PSL_TF, or PSL_I when VIP is set */
222 		case IRET:
223 			vmf->vmf_ip = POP(vmf);
224 			vmf->vmf_cs = POP(vmf);
225 			temp_flags = POP(vmf) & POP_MASK;
226 			vmf->vmf_flags = (vmf->vmf_flags & ~POP_MASK)
227 			    | temp_flags | PSL_VM | PSL_I;
228 			if (temp_flags & PSL_I) {
229 				vmf->vmf_eflags |= PSL_VIF;
230 				if (vmf->vmf_eflags & PSL_VIP)
231 					break;
232 			} else {
233 				vmf->vmf_eflags &= ~PSL_VIF;
234 			}
235 			return (retcode);
236 
237 		}
238 		return (SIGBUS);
239 	}
240 
241 	switch (i_byte) {
242 	case OPERAND_SIZE_PREFIX:
243 		i_byte = fubyte(++addr);
244 		inc_ip++;
245 		switch (i_byte) {
246 		case PUSHF:
247 			if (vm86->vm86_eflags & PSL_VIF)
248 				PUSHL((vmf->vmf_flags & PUSH_MASK)
249 				    | PSL_IOPL | PSL_I, vmf);
250 			else
251 				PUSHL((vmf->vmf_flags & PUSH_MASK)
252 				    | PSL_IOPL, vmf);
253 			vmf->vmf_ip += inc_ip;
254 			return (retcode);
255 
256 		case POPF:
257 			temp_flags = POPL(vmf) & POP_MASK;
258 			vmf->vmf_eflags = (vmf->vmf_eflags & ~POP_MASK)
259 			    | temp_flags | PSL_VM | PSL_I;
260 			vmf->vmf_ip += inc_ip;
261 			if (temp_flags & PSL_I) {
262 				vm86->vm86_eflags |= PSL_VIF;
263 				if (vm86->vm86_eflags & PSL_VIP)
264 					break;
265 			} else {
266 				vm86->vm86_eflags &= ~PSL_VIF;
267 			}
268 			return (retcode);
269 		}
270 		return (SIGBUS);
271 
272 	case CLI:
273 		vm86->vm86_eflags &= ~PSL_VIF;
274 		vmf->vmf_ip += inc_ip;
275 		return (retcode);
276 
277 	case STI:
278 		/* if there is a pending interrupt, go to the emulator */
279 		vm86->vm86_eflags |= PSL_VIF;
280 		vmf->vmf_ip += inc_ip;
281 		if (vm86->vm86_eflags & PSL_VIP)
282 			break;
283 		return (retcode);
284 
285 	case PUSHF:
286 		if (vm86->vm86_eflags & PSL_VIF)
287 			PUSH((vmf->vmf_flags & PUSH_MASK)
288 			    | PSL_IOPL | PSL_I, vmf);
289 		else
290 			PUSH((vmf->vmf_flags & PUSH_MASK) | PSL_IOPL, vmf);
291 		vmf->vmf_ip += inc_ip;
292 		return (retcode);
293 
294 	case INTn:
295 		i_byte = fubyte(addr + 1);
296 		if ((vm86->vm86_intmap[i_byte >> 3] & (1 << (i_byte & 7))) != 0)
297 			break;
298 		if (vm86->vm86_eflags & PSL_VIF)
299 			PUSH((vmf->vmf_flags & PUSH_MASK)
300 			    | PSL_IOPL | PSL_I, vmf);
301 		else
302 			PUSH((vmf->vmf_flags & PUSH_MASK) | PSL_IOPL, vmf);
303 		PUSH(vmf->vmf_cs, vmf);
304 		PUSH(vmf->vmf_ip + inc_ip + 1, vmf);	/* increment IP */
305 		GET_VEC(fuword((caddr_t)(i_byte * 4)),
306 		     &vmf->vmf_cs, &vmf->vmf_ip);
307 		vmf->vmf_flags &= ~PSL_T;
308 		vm86->vm86_eflags &= ~PSL_VIF;
309 		return (retcode);
310 
311 	case IRET:
312 		vmf->vmf_ip = POP(vmf);
313 		vmf->vmf_cs = POP(vmf);
314 		temp_flags = POP(vmf) & POP_MASK;
315 		vmf->vmf_flags = (vmf->vmf_flags & ~POP_MASK)
316 		    | temp_flags | PSL_VM | PSL_I;
317 		if (temp_flags & PSL_I) {
318 			vm86->vm86_eflags |= PSL_VIF;
319 			if (vm86->vm86_eflags & PSL_VIP)
320 				break;
321 		} else {
322 			vm86->vm86_eflags &= ~PSL_VIF;
323 		}
324 		return (retcode);
325 
326 	case POPF:
327 		temp_flags = POP(vmf) & POP_MASK;
328 		vmf->vmf_flags = (vmf->vmf_flags & ~POP_MASK)
329 		    | temp_flags | PSL_VM | PSL_I;
330 		vmf->vmf_ip += inc_ip;
331 		if (temp_flags & PSL_I) {
332 			vm86->vm86_eflags |= PSL_VIF;
333 			if (vm86->vm86_eflags & PSL_VIP)
334 				break;
335 		} else {
336 			vm86->vm86_eflags &= ~PSL_VIF;
337 		}
338 		return (retcode);
339 	}
340 	return (SIGBUS);
341 }
342 
343 #define PGTABLE_SIZE	((1024 + 64) * 1024 / PAGE_SIZE)
344 #define INTMAP_SIZE	32
345 #define IOMAP_SIZE	ctob(IOPAGES)
346 #define TSS_SIZE \
347 	(sizeof(struct pcb_ext) - sizeof(struct segment_descriptor) + \
348 	 INTMAP_SIZE + IOMAP_SIZE + 1)
349 
350 struct vm86_layout {
351 	pt_entry_t	vml_pgtbl[PGTABLE_SIZE];
352 	struct 	pcb vml_pcb;
353 	struct	pcb_ext vml_ext;
354 	char	vml_intmap[INTMAP_SIZE];
355 	char	vml_iomap[IOMAP_SIZE];
356 	char	vml_iomap_trailer;
357 };
358 
359 void
360 vm86_initialize(void)
361 {
362 	int i;
363 	u_int *addr;
364 	struct vm86_layout *vml = (struct vm86_layout *)vm86paddr;
365 	struct pcb *pcb;
366 	struct pcb_ext *ext;
367 	struct soft_segment_descriptor ssd = {
368 		0,			/* segment base address (overwritten) */
369 		0,			/* length (overwritten) */
370 		SDT_SYS386TSS,		/* segment type */
371 		0,			/* priority level */
372 		1,			/* descriptor present */
373 		0, 0,
374 		0,			/* default 16 size */
375 		0			/* granularity */
376 	};
377 
378 	/*
379 	 * this should be a compile time error, but cpp doesn't grok sizeof().
380 	 */
381 	if (sizeof(struct vm86_layout) > ctob(3))
382 		panic("struct vm86_layout exceeds space allocated in locore.s");
383 
384 	/*
385 	 * Below is the memory layout that we use for the vm86 region.
386 	 *
387 	 * +--------+
388 	 * |        |
389 	 * |        |
390 	 * | page 0 |
391 	 * |        | +--------+
392 	 * |        | | stack  |
393 	 * +--------+ +--------+ <--------- vm86paddr
394 	 * |        | |Page Tbl| 1M + 64K = 272 entries = 1088 bytes
395 	 * |        | +--------+
396 	 * |        | |  PCB   | size: ~240 bytes
397 	 * | page 1 | |PCB Ext | size: ~140 bytes (includes TSS)
398 	 * |        | +--------+
399 	 * |        | |int map |
400 	 * |        | +--------+
401 	 * +--------+ |        |
402 	 * | page 2 | |  I/O   |
403 	 * +--------+ | bitmap |
404 	 * | page 3 | |        |
405 	 * |        | +--------+
406 	 * +--------+
407 	 */
408 
409 	/*
410 	 * A rudimentary PCB must be installed, in order to get to the
411 	 * PCB extension area.  We use the PCB area as a scratchpad for
412 	 * data storage, the layout of which is shown below.
413 	 *
414 	 * pcb_esi	= new PTD entry 0
415 	 * pcb_ebp	= pointer to frame on vm86 stack
416 	 * pcb_esp	=    stack frame pointer at time of switch
417 	 * pcb_ebx	= va of vm86 page table
418 	 * pcb_eip	=    argument pointer to initial call
419 	 * pcb_spare[0]	=    saved TSS descriptor, word 0
420 	 * pcb_space[1]	=    saved TSS descriptor, word 1
421 	 */
422 #define new_ptd		pcb_esi
423 #define vm86_frame	pcb_ebp
424 #define pgtable_va	pcb_ebx
425 
426 	pcb = &vml->vml_pcb;
427 	ext = &vml->vml_ext;
428 
429 	mtx_init(&vm86_lock, "vm86 lock", NULL, MTX_DEF);
430 
431 	bzero(pcb, sizeof(struct pcb));
432 	pcb->new_ptd = vm86pa | PG_V | PG_RW | PG_U;
433 	pcb->vm86_frame = vm86paddr - sizeof(struct vm86frame);
434 	pcb->pgtable_va = vm86paddr;
435 	pcb->pcb_flags = PCB_VM86CALL;
436 	pcb->pcb_ext = ext;
437 
438 	bzero(ext, sizeof(struct pcb_ext));
439 	ext->ext_tss.tss_esp0 = vm86paddr;
440 	ext->ext_tss.tss_ss0 = GSEL(GDATA_SEL, SEL_KPL);
441 	ext->ext_tss.tss_ioopt =
442 		((u_int)vml->vml_iomap - (u_int)&ext->ext_tss) << 16;
443 	ext->ext_iomap = vml->vml_iomap;
444 	ext->ext_vm86.vm86_intmap = vml->vml_intmap;
445 
446 	if (cpu_feature & CPUID_VME)
447 		ext->ext_vm86.vm86_has_vme = (rcr4() & CR4_VME ? 1 : 0);
448 
449 	addr = (u_int *)ext->ext_vm86.vm86_intmap;
450 	for (i = 0; i < (INTMAP_SIZE + IOMAP_SIZE) / sizeof(u_int); i++)
451 		*addr++ = 0;
452 	vml->vml_iomap_trailer = 0xff;
453 
454 	ssd.ssd_base = (u_int)&ext->ext_tss;
455 	ssd.ssd_limit = TSS_SIZE - 1;
456 	ssdtosd(&ssd, &ext->ext_tssd);
457 
458 	vm86pcb = pcb;
459 
460 #if 0
461         /*
462          * use whatever is leftover of the vm86 page layout as a
463          * message buffer so we can capture early output.
464          */
465         msgbufinit((vm_offset_t)vm86paddr + sizeof(struct vm86_layout),
466             ctob(3) - sizeof(struct vm86_layout));
467 #endif
468 }
469 
470 vm_offset_t
471 vm86_getpage(struct vm86context *vmc, int pagenum)
472 {
473 	int i;
474 
475 	for (i = 0; i < vmc->npages; i++)
476 		if (vmc->pmap[i].pte_num == pagenum)
477 			return (vmc->pmap[i].kva);
478 	return (0);
479 }
480 
481 vm_offset_t
482 vm86_addpage(struct vm86context *vmc, int pagenum, vm_offset_t kva)
483 {
484 	int i, flags = 0;
485 
486 	for (i = 0; i < vmc->npages; i++)
487 		if (vmc->pmap[i].pte_num == pagenum)
488 			goto overlap;
489 
490 	if (vmc->npages == VM86_PMAPSIZE)
491 		goto full;			/* XXX grow map? */
492 
493 	if (kva == 0) {
494 		kva = (vm_offset_t)malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
495 		flags = VMAP_MALLOC;
496 	}
497 
498 	i = vmc->npages++;
499 	vmc->pmap[i].flags = flags;
500 	vmc->pmap[i].kva = kva;
501 	vmc->pmap[i].pte_num = pagenum;
502 	return (kva);
503 overlap:
504 	panic("vm86_addpage: overlap");
505 full:
506 	panic("vm86_addpage: not enough room");
507 }
508 
509 /*
510  * called from vm86_bioscall, while in vm86 address space, to finalize setup.
511  */
512 void
513 vm86_prepcall(struct vm86frame *vmf)
514 {
515 	struct vm86_kernel *vm86;
516 	uint32_t *stack;
517 	uint8_t *code;
518 
519 	code = (void *)0xa00;
520 	stack = (void *)(0x1000 - 2);	/* keep aligned */
521 	if ((vmf->vmf_trapno & PAGE_MASK) <= 0xff) {
522 		/* interrupt call requested */
523 		code[0] = INTn;
524 		code[1] = vmf->vmf_trapno & 0xff;
525 		code[2] = HLT;
526 		vmf->vmf_ip = (uintptr_t)code;
527 		vmf->vmf_cs = 0;
528 	} else {
529 		code[0] = HLT;
530 		stack--;
531 		stack[0] = MAKE_VEC(0, (uintptr_t)code);
532 	}
533 	vmf->vmf_sp = (uintptr_t)stack;
534 	vmf->vmf_ss = 0;
535 	vmf->kernel_fs = vmf->kernel_es = vmf->kernel_ds = 0;
536 	vmf->vmf_eflags = PSL_VIF | PSL_VM | PSL_USER;
537 
538 	vm86 = &curpcb->pcb_ext->ext_vm86;
539 	if (!vm86->vm86_has_vme)
540 		vm86->vm86_eflags = vmf->vmf_eflags;  /* save VIF, VIP */
541 }
542 
543 /*
544  * vm86 trap handler; determines whether routine succeeded or not.
545  * Called while in vm86 space, returns to calling process.
546  */
547 void
548 vm86_trap(struct vm86frame *vmf)
549 {
550 	caddr_t addr;
551 
552 	/* "should not happen" */
553 	if ((vmf->vmf_eflags & PSL_VM) == 0)
554 		panic("vm86_trap called, but not in vm86 mode");
555 
556 	addr = MAKE_ADDR(vmf->vmf_cs, vmf->vmf_ip);
557 	if (*(u_char *)addr == HLT)
558 		vmf->vmf_trapno = vmf->vmf_eflags & PSL_C;
559 	else
560 		vmf->vmf_trapno = vmf->vmf_trapno << 16;
561 
562 	vm86_biosret(vmf);
563 }
564 
565 int
566 vm86_intcall(int intnum, struct vm86frame *vmf)
567 {
568 	int retval;
569 
570 	if (intnum < 0 || intnum > 0xff)
571 		return (EINVAL);
572 
573 	vmf->vmf_trapno = intnum;
574 	mtx_lock(&vm86_lock);
575 	critical_enter();
576 	retval = vm86_bioscall(vmf);
577 	critical_exit();
578 	mtx_unlock(&vm86_lock);
579 	return (retval);
580 }
581 
582 /*
583  * struct vm86context contains the page table to use when making
584  * vm86 calls.  If intnum is a valid interrupt number (0-255), then
585  * the "interrupt trampoline" will be used, otherwise we use the
586  * caller's cs:ip routine.
587  */
588 int
589 vm86_datacall(intnum, vmf, vmc)
590 	int intnum;
591 	struct vm86frame *vmf;
592 	struct vm86context *vmc;
593 {
594 	pt_entry_t *pte = (pt_entry_t *)vm86paddr;
595 	vm_paddr_t page;
596 	int i, entry, retval;
597 
598 	mtx_lock(&vm86_lock);
599 	for (i = 0; i < vmc->npages; i++) {
600 		page = vtophys(vmc->pmap[i].kva & PG_FRAME);
601 		entry = vmc->pmap[i].pte_num;
602 		vmc->pmap[i].old_pte = pte[entry];
603 		pte[entry] = page | PG_V | PG_RW | PG_U;
604 		pmap_invalidate_page(kernel_pmap, vmc->pmap[i].kva);
605 	}
606 
607 	vmf->vmf_trapno = intnum;
608 	critical_enter();
609 	retval = vm86_bioscall(vmf);
610 	critical_exit();
611 
612 	for (i = 0; i < vmc->npages; i++) {
613 		entry = vmc->pmap[i].pte_num;
614 		pte[entry] = vmc->pmap[i].old_pte;
615 		pmap_invalidate_page(kernel_pmap, vmc->pmap[i].kva);
616 	}
617 	mtx_unlock(&vm86_lock);
618 
619 	return (retval);
620 }
621 
622 vm_offset_t
623 vm86_getaddr(struct vm86context *vmc, u_short sel, u_short off)
624 {
625 	int i, page;
626 	vm_offset_t addr;
627 
628 	addr = (vm_offset_t)MAKE_ADDR(sel, off);
629 	page = addr >> PAGE_SHIFT;
630 	for (i = 0; i < vmc->npages; i++)
631 		if (page == vmc->pmap[i].pte_num)
632 			return (vmc->pmap[i].kva + (addr & PAGE_MASK));
633 	return (0);
634 }
635 
636 int
637 vm86_getptr(vmc, kva, sel, off)
638 	struct vm86context *vmc;
639 	vm_offset_t kva;
640 	u_short *sel;
641 	u_short *off;
642 {
643 	int i;
644 
645 	for (i = 0; i < vmc->npages; i++)
646 		if (kva >= vmc->pmap[i].kva &&
647 		    kva < vmc->pmap[i].kva + PAGE_SIZE) {
648 			*off = kva - vmc->pmap[i].kva;
649 			*sel = vmc->pmap[i].pte_num << 8;
650 			return (1);
651 		}
652 	return (0);
653 }
654 
655 int
656 vm86_sysarch(td, args)
657 	struct thread *td;
658 	char *args;
659 {
660 	int error = 0;
661 	struct i386_vm86_args ua;
662 	struct vm86_kernel *vm86;
663 
664 	if ((error = copyin(args, &ua, sizeof(struct i386_vm86_args))) != 0)
665 		return (error);
666 
667 	if (td->td_pcb->pcb_ext == 0)
668 		if ((error = i386_extend_pcb(td)) != 0)
669 			return (error);
670 	vm86 = &td->td_pcb->pcb_ext->ext_vm86;
671 
672 	switch (ua.sub_op) {
673 	case VM86_INIT: {
674 		struct vm86_init_args sa;
675 
676 		if ((error = copyin(ua.sub_args, &sa, sizeof(sa))) != 0)
677 			return (error);
678 		if (cpu_feature & CPUID_VME)
679 			vm86->vm86_has_vme = (rcr4() & CR4_VME ? 1 : 0);
680 		else
681 			vm86->vm86_has_vme = 0;
682 		vm86->vm86_inited = 1;
683 		vm86->vm86_debug = sa.debug;
684 		bcopy(&sa.int_map, vm86->vm86_intmap, 32);
685 		}
686 		break;
687 
688 #if 0
689 	case VM86_SET_VME: {
690 		struct vm86_vme_args sa;
691 
692 		if ((cpu_feature & CPUID_VME) == 0)
693 			return (ENODEV);
694 
695 		if (error = copyin(ua.sub_args, &sa, sizeof(sa)))
696 			return (error);
697 		if (sa.state)
698 			load_cr4(rcr4() | CR4_VME);
699 		else
700 			load_cr4(rcr4() & ~CR4_VME);
701 		}
702 		break;
703 #endif
704 
705 	case VM86_GET_VME: {
706 		struct vm86_vme_args sa;
707 
708 		sa.state = (rcr4() & CR4_VME ? 1 : 0);
709         	error = copyout(&sa, ua.sub_args, sizeof(sa));
710 		}
711 		break;
712 
713 	case VM86_INTCALL: {
714 		struct vm86_intcall_args sa;
715 
716 		if ((error = priv_check(td, PRIV_VM86_INTCALL)))
717 			return (error);
718 		if ((error = copyin(ua.sub_args, &sa, sizeof(sa))))
719 			return (error);
720 		if ((error = vm86_intcall(sa.intnum, &sa.vmf)))
721 			return (error);
722 		error = copyout(&sa, ua.sub_args, sizeof(sa));
723 		}
724 		break;
725 
726 	default:
727 		error = EINVAL;
728 	}
729 	return (error);
730 }
731