2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
6 * Main entry point for the guest, exception handling.
8 * Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
9 * Authors: Sanjay Lal <sanjayl@kymasys.com>
13 #include <asm/asmmacro.h>
14 #include <asm/regdef.h>
15 #include <asm/mipsregs.h>
16 #include <asm/stackframe.h>
17 #include <asm/asm-offsets.h>
20 #define MIPSX(name) mips32_ ## name
21 #define CALLFRAME_SIZ 32
25 * exception vector entrypoint
27 #define VECTOR(x, regmask) \
31 #define VECTOR_END(x) \
34 /* Overload, Danger Will Robinson!! */
35 #define PT_HOST_ASID PT_BVADDR
36 #define PT_HOST_USERLOCAL PT_EPC
38 #define CP0_DDATA_LO $28,3
39 #define CP0_EBASE $15,1
41 #define CP0_INTCTL $12,1
42 #define CP0_SRSCTL $12,2
43 #define CP0_SRSMAP $12,3
44 #define CP0_HWRENA $7,0
47 #define RESUME_FLAG_HOST (1<<1) /* Resume host? */
49 #define RESUME_GUEST 0
50 #define RESUME_HOST RESUME_FLAG_HOST
53 * __kvm_mips_vcpu_run: entry point to the guest
60 FEXPORT(__kvm_mips_vcpu_run)
61 /* k0/k1 not being used in host kernel context */
62 INT_ADDIU k1, sp, -PT_SIZE
75 LONG_S $10, PT_R10(k1)
76 LONG_S $11, PT_R11(k1)
77 LONG_S $12, PT_R12(k1)
78 LONG_S $13, PT_R13(k1)
79 LONG_S $14, PT_R14(k1)
80 LONG_S $15, PT_R15(k1)
81 LONG_S $16, PT_R16(k1)
82 LONG_S $17, PT_R17(k1)
84 LONG_S $18, PT_R18(k1)
85 LONG_S $19, PT_R19(k1)
86 LONG_S $20, PT_R20(k1)
87 LONG_S $21, PT_R21(k1)
88 LONG_S $22, PT_R22(k1)
89 LONG_S $23, PT_R23(k1)
90 LONG_S $24, PT_R24(k1)
91 LONG_S $25, PT_R25(k1)
94 * XXXKYMA k0/k1 not saved, not being used if we got here through
98 LONG_S $28, PT_R28(k1)
99 LONG_S $29, PT_R29(k1)
100 LONG_S $30, PT_R30(k1)
101 LONG_S $31, PT_R31(k1)
109 /* Save host status */
111 LONG_S v0, PT_STATUS(k1)
113 /* Save host ASID, shove it into the BVADDR location */
116 LONG_S v1, PT_HOST_ASID(k1)
118 /* Save DDATA_LO, will be used to store pointer to vcpu */
119 mfc0 v1, CP0_DDATA_LO
120 LONG_S v1, PT_HOST_USERLOCAL(k1)
122 /* DDATA_LO has pointer to vcpu */
123 mtc0 a1, CP0_DDATA_LO
125 /* Offset into vcpu->arch */
126 INT_ADDIU k1, a1, VCPU_HOST_ARCH
129 * Save the host stack to VCPU, used for exception processing
130 * when we exit from the Guest
132 LONG_S sp, VCPU_HOST_STACK(k1)
134 /* Save the kernel gp as well */
135 LONG_S gp, VCPU_HOST_GP(k1)
138 * Setup status register for running the guest in UM, interrupts
141 li k0, (ST0_EXL | KSU_USER | ST0_BEV)
145 /* load up the new EBASE */
146 LONG_L k0, VCPU_GUEST_EBASE(k1)
150 * Now that the new EBASE has been loaded, unset BEV, set
151 * interrupt mask as it was but make sure that timer interrupts
154 li k0, (ST0_EXL | KSU_USER | ST0_IE)
161 LONG_L t0, VCPU_PC(k1)
164 FEXPORT(__kvm_mips_load_asid)
165 /* Set the ASID for the Guest Kernel */
166 INT_SLL t0, t0, 1 /* with kseg0 @ 0x40000000, kernel */
167 /* addresses shift to 0x80000000 */
168 bltz t0, 1f /* If kernel */
169 INT_ADDIU t1, k1, VCPU_GUEST_KERNEL_ASID /* (BD) */
170 INT_ADDIU t1, k1, VCPU_GUEST_USER_ASID /* else user */
172 /* t1: contains the base of the ASID array, need to get the cpu id */
173 LONG_L t2, TI_CPU($28) /* smp_processor_id */
174 INT_SLL t2, t2, 2 /* x4 */
181 /* Disable RDHWR access */
182 mtc0 zero, CP0_HWRENA
184 /* Now load up the Guest Context from VCPU */
185 LONG_L $1, VCPU_R1(k1)
186 LONG_L $2, VCPU_R2(k1)
187 LONG_L $3, VCPU_R3(k1)
189 LONG_L $4, VCPU_R4(k1)
190 LONG_L $5, VCPU_R5(k1)
191 LONG_L $6, VCPU_R6(k1)
192 LONG_L $7, VCPU_R7(k1)
194 LONG_L $8, VCPU_R8(k1)
195 LONG_L $9, VCPU_R9(k1)
196 LONG_L $10, VCPU_R10(k1)
197 LONG_L $11, VCPU_R11(k1)
198 LONG_L $12, VCPU_R12(k1)
199 LONG_L $13, VCPU_R13(k1)
200 LONG_L $14, VCPU_R14(k1)
201 LONG_L $15, VCPU_R15(k1)
202 LONG_L $16, VCPU_R16(k1)
203 LONG_L $17, VCPU_R17(k1)
204 LONG_L $18, VCPU_R18(k1)
205 LONG_L $19, VCPU_R19(k1)
206 LONG_L $20, VCPU_R20(k1)
207 LONG_L $21, VCPU_R21(k1)
208 LONG_L $22, VCPU_R22(k1)
209 LONG_L $23, VCPU_R23(k1)
210 LONG_L $24, VCPU_R24(k1)
211 LONG_L $25, VCPU_R25(k1)
213 /* k0/k1 loaded up later */
215 LONG_L $28, VCPU_R28(k1)
216 LONG_L $29, VCPU_R29(k1)
217 LONG_L $30, VCPU_R30(k1)
218 LONG_L $31, VCPU_R31(k1)
221 LONG_L k0, VCPU_LO(k1)
224 LONG_L k0, VCPU_HI(k1)
227 FEXPORT(__kvm_mips_load_k0k1)
228 /* Restore the guest's k0/k1 registers */
229 LONG_L k0, VCPU_R26(k1)
230 LONG_L k1, VCPU_R27(k1)
235 VECTOR(MIPSX(exception), unknown)
236 /* Find out what mode we came from and jump to the proper handler. */
237 mtc0 k0, CP0_ERROREPC #01: Save guest k0
240 mfc0 k0, CP0_EBASE #02: Get EBASE
241 INT_SRL k0, k0, 10 #03: Get rid of CPUNum
242 INT_SLL k0, k0, 10 #04
243 LONG_S k1, 0x3000(k0) #05: Save k1 @ offset 0x3000
244 INT_ADDIU k0, k0, 0x2000 #06: Exception handler is
245 # installed @ offset 0x2000
246 j k0 #07: jump to the function
247 nop #08: branch delay slot
248 VECTOR_END(MIPSX(exceptionEnd))
249 .end MIPSX(exception)
252 * Generic Guest exception handler. We end up here when the guest
253 * does something that causes a trap to kernel mode.
255 NESTED (MIPSX(GuestException), CALLFRAME_SIZ, ra)
256 /* Get the VCPU pointer from DDTATA_LO */
257 mfc0 k1, CP0_DDATA_LO
258 INT_ADDIU k1, k1, VCPU_HOST_ARCH
260 /* Start saving Guest context to VCPU */
261 LONG_S $0, VCPU_R0(k1)
262 LONG_S $1, VCPU_R1(k1)
263 LONG_S $2, VCPU_R2(k1)
264 LONG_S $3, VCPU_R3(k1)
265 LONG_S $4, VCPU_R4(k1)
266 LONG_S $5, VCPU_R5(k1)
267 LONG_S $6, VCPU_R6(k1)
268 LONG_S $7, VCPU_R7(k1)
269 LONG_S $8, VCPU_R8(k1)
270 LONG_S $9, VCPU_R9(k1)
271 LONG_S $10, VCPU_R10(k1)
272 LONG_S $11, VCPU_R11(k1)
273 LONG_S $12, VCPU_R12(k1)
274 LONG_S $13, VCPU_R13(k1)
275 LONG_S $14, VCPU_R14(k1)
276 LONG_S $15, VCPU_R15(k1)
277 LONG_S $16, VCPU_R16(k1)
278 LONG_S $17, VCPU_R17(k1)
279 LONG_S $18, VCPU_R18(k1)
280 LONG_S $19, VCPU_R19(k1)
281 LONG_S $20, VCPU_R20(k1)
282 LONG_S $21, VCPU_R21(k1)
283 LONG_S $22, VCPU_R22(k1)
284 LONG_S $23, VCPU_R23(k1)
285 LONG_S $24, VCPU_R24(k1)
286 LONG_S $25, VCPU_R25(k1)
288 /* Guest k0/k1 saved later */
290 LONG_S $28, VCPU_R28(k1)
291 LONG_S $29, VCPU_R29(k1)
292 LONG_S $30, VCPU_R30(k1)
293 LONG_S $31, VCPU_R31(k1)
295 /* We need to save hi/lo and restore them on the way out */
297 LONG_S t0, VCPU_HI(k1)
300 LONG_S t0, VCPU_LO(k1)
302 /* Finally save guest k0/k1 to VCPU */
303 mfc0 t0, CP0_ERROREPC
304 LONG_S t0, VCPU_R26(k1)
306 /* Get GUEST k1 and save it in VCPU */
310 LONG_L t0, 0x3000(t0)
311 LONG_S t0, VCPU_R27(k1)
313 /* Now that context has been saved, we can use other registers */
316 mfc0 a1, CP0_DDATA_LO
319 /* Restore run (vcpu->run) */
320 LONG_L a0, VCPU_RUN(a1)
321 /* Save pointer to run in s0, will be saved by the compiler */
325 * Save Host level EPC, BadVaddr and Cause to VCPU, useful to
326 * process the exception
329 LONG_S k0, VCPU_PC(k1)
331 mfc0 k0, CP0_BADVADDR
332 LONG_S k0, VCPU_HOST_CP0_BADVADDR(k1)
335 LONG_S k0, VCPU_HOST_CP0_CAUSE(k1)
338 LONG_S k0, VCPU_HOST_ENTRYHI(k1)
340 /* Now restore the host state just enough to run the handlers */
342 /* Swtich EBASE to the one used by Linux */
343 /* load up the host EBASE */
353 LONG_L k0, VCPU_HOST_EBASE(k1)
356 /* Now that the new EBASE has been loaded, unset BEV and KSU_USER */
358 and v0, v0, ~(ST0_EXL | KSU_USER | ST0_IE)
364 /* Load up host GP */
365 LONG_L gp, VCPU_HOST_GP(k1)
367 /* Need a stack before we can jump to "C" */
368 LONG_L sp, VCPU_HOST_STACK(k1)
370 /* Saved host state */
371 INT_ADDIU sp, sp, -PT_SIZE
374 * XXXKYMA do we need to load the host ASID, maybe not because the
375 * kernel entries are marked GLOBAL, need to verify
378 /* Restore host DDATA_LO */
379 LONG_L k0, PT_HOST_USERLOCAL(sp)
380 mtc0 k0, CP0_DDATA_LO
382 /* Restore RDHWR access */
383 PTR_LI k0, 0x2000000F
386 /* Jump to handler */
387 FEXPORT(__kvm_mips_jump_to_handler)
389 * XXXKYMA: not sure if this is safe, how large is the stack??
390 * Now jump to the kvm_mips_handle_exit() to see if we can deal
391 * with this in the kernel
393 PTR_LA t9, kvm_mips_handle_exit
395 INT_ADDIU sp, sp, -CALLFRAME_SIZ /* BD Slot */
397 /* Return from handler Make sure interrupts are disabled */
402 * XXXKYMA: k0/k1 could have been blown away if we processed
403 * an exception while we were handling the exception from the
408 INT_ADDIU k1, k1, VCPU_HOST_ARCH
411 * Check return value, should tell us if we are returning to the
412 * host (handle I/O etc)or resuming the guest
414 andi t0, v0, RESUME_HOST
415 bnez t0, __kvm_mips_return_to_host
418 __kvm_mips_return_to_guest:
419 /* Put the saved pointer to vcpu (s1) back into the DDATA_LO Register */
420 mtc0 s1, CP0_DDATA_LO
422 /* Load up the Guest EBASE to minimize the window where BEV is set */
423 LONG_L t0, VCPU_GUEST_EBASE(k1)
425 /* Switch EBASE back to the one used by KVM */
434 /* Setup status register for running guest in UM */
436 or v1, v1, (ST0_EXL | KSU_USER | ST0_IE)
443 LONG_L t0, VCPU_PC(k1)
446 /* Set the ASID for the Guest Kernel */
447 INT_SLL t0, t0, 1 /* with kseg0 @ 0x40000000, kernel */
448 /* addresses shift to 0x80000000 */
449 bltz t0, 1f /* If kernel */
450 INT_ADDIU t1, k1, VCPU_GUEST_KERNEL_ASID /* (BD) */
451 INT_ADDIU t1, k1, VCPU_GUEST_USER_ASID /* else user */
453 /* t1: contains the base of the ASID array, need to get the cpu id */
454 LONG_L t2, TI_CPU($28) /* smp_processor_id */
455 INT_SLL t2, t2, 2 /* x4 */
462 /* Disable RDHWR access */
463 mtc0 zero, CP0_HWRENA
465 /* load the guest context from VCPU and return */
466 LONG_L $0, VCPU_R0(k1)
467 LONG_L $1, VCPU_R1(k1)
468 LONG_L $2, VCPU_R2(k1)
469 LONG_L $3, VCPU_R3(k1)
470 LONG_L $4, VCPU_R4(k1)
471 LONG_L $5, VCPU_R5(k1)
472 LONG_L $6, VCPU_R6(k1)
473 LONG_L $7, VCPU_R7(k1)
474 LONG_L $8, VCPU_R8(k1)
475 LONG_L $9, VCPU_R9(k1)
476 LONG_L $10, VCPU_R10(k1)
477 LONG_L $11, VCPU_R11(k1)
478 LONG_L $12, VCPU_R12(k1)
479 LONG_L $13, VCPU_R13(k1)
480 LONG_L $14, VCPU_R14(k1)
481 LONG_L $15, VCPU_R15(k1)
482 LONG_L $16, VCPU_R16(k1)
483 LONG_L $17, VCPU_R17(k1)
484 LONG_L $18, VCPU_R18(k1)
485 LONG_L $19, VCPU_R19(k1)
486 LONG_L $20, VCPU_R20(k1)
487 LONG_L $21, VCPU_R21(k1)
488 LONG_L $22, VCPU_R22(k1)
489 LONG_L $23, VCPU_R23(k1)
490 LONG_L $24, VCPU_R24(k1)
491 LONG_L $25, VCPU_R25(k1)
493 /* $/k1 loaded later */
494 LONG_L $28, VCPU_R28(k1)
495 LONG_L $29, VCPU_R29(k1)
496 LONG_L $30, VCPU_R30(k1)
497 LONG_L $31, VCPU_R31(k1)
499 FEXPORT(__kvm_mips_skip_guest_restore)
500 LONG_L k0, VCPU_HI(k1)
503 LONG_L k0, VCPU_LO(k1)
506 LONG_L k0, VCPU_R26(k1)
507 LONG_L k1, VCPU_R27(k1)
511 __kvm_mips_return_to_host:
512 /* EBASE is already pointing to Linux */
513 LONG_L k1, VCPU_HOST_STACK(k1)
514 INT_ADDIU k1,k1, -PT_SIZE
516 /* Restore host DDATA_LO */
517 LONG_L k0, PT_HOST_USERLOCAL(k1)
518 mtc0 k0, CP0_DDATA_LO
520 /* Restore host ASID */
521 LONG_L k0, PT_HOST_ASID(sp)
526 /* Load context saved on the host stack */
531 * r2/v0 is the return code, shift it down by 2 (arithmetic)
532 * to recover the err code
544 LONG_L $10, PT_R10(k1)
545 LONG_L $11, PT_R11(k1)
546 LONG_L $12, PT_R12(k1)
547 LONG_L $13, PT_R13(k1)
548 LONG_L $14, PT_R14(k1)
549 LONG_L $15, PT_R15(k1)
550 LONG_L $16, PT_R16(k1)
551 LONG_L $17, PT_R17(k1)
552 LONG_L $18, PT_R18(k1)
553 LONG_L $19, PT_R19(k1)
554 LONG_L $20, PT_R20(k1)
555 LONG_L $21, PT_R21(k1)
556 LONG_L $22, PT_R22(k1)
557 LONG_L $23, PT_R23(k1)
558 LONG_L $24, PT_R24(k1)
559 LONG_L $25, PT_R25(k1)
561 /* Host k0/k1 were not saved */
563 LONG_L $28, PT_R28(k1)
564 LONG_L $29, PT_R29(k1)
565 LONG_L $30, PT_R30(k1)
573 /* Restore RDHWR access */
574 PTR_LI k0, 0x2000000F
577 /* Restore RA, which is the address we will return to */
578 LONG_L ra, PT_R31(k1)
582 VECTOR_END(MIPSX(GuestExceptionEnd))
583 .end MIPSX(GuestException)
587 ##### The exception handlers.
589 .word _C_LABEL(MIPSX(GuestException)) # 0
590 .word _C_LABEL(MIPSX(GuestException)) # 1
591 .word _C_LABEL(MIPSX(GuestException)) # 2
592 .word _C_LABEL(MIPSX(GuestException)) # 3
593 .word _C_LABEL(MIPSX(GuestException)) # 4
594 .word _C_LABEL(MIPSX(GuestException)) # 5
595 .word _C_LABEL(MIPSX(GuestException)) # 6
596 .word _C_LABEL(MIPSX(GuestException)) # 7
597 .word _C_LABEL(MIPSX(GuestException)) # 8
598 .word _C_LABEL(MIPSX(GuestException)) # 9
599 .word _C_LABEL(MIPSX(GuestException)) # 10
600 .word _C_LABEL(MIPSX(GuestException)) # 11
601 .word _C_LABEL(MIPSX(GuestException)) # 12
602 .word _C_LABEL(MIPSX(GuestException)) # 13
603 .word _C_LABEL(MIPSX(GuestException)) # 14
604 .word _C_LABEL(MIPSX(GuestException)) # 15
605 .word _C_LABEL(MIPSX(GuestException)) # 16
606 .word _C_LABEL(MIPSX(GuestException)) # 17
607 .word _C_LABEL(MIPSX(GuestException)) # 18
608 .word _C_LABEL(MIPSX(GuestException)) # 19
609 .word _C_LABEL(MIPSX(GuestException)) # 20
610 .word _C_LABEL(MIPSX(GuestException)) # 21
611 .word _C_LABEL(MIPSX(GuestException)) # 22
612 .word _C_LABEL(MIPSX(GuestException)) # 23
613 .word _C_LABEL(MIPSX(GuestException)) # 24
614 .word _C_LABEL(MIPSX(GuestException)) # 25
615 .word _C_LABEL(MIPSX(GuestException)) # 26
616 .word _C_LABEL(MIPSX(GuestException)) # 27
617 .word _C_LABEL(MIPSX(GuestException)) # 28
618 .word _C_LABEL(MIPSX(GuestException)) # 29
619 .word _C_LABEL(MIPSX(GuestException)) # 30
620 .word _C_LABEL(MIPSX(GuestException)) # 31