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Diffstat (limited to 'arch/mips/kvm/locore.S')
| -rw-r--r-- | arch/mips/kvm/locore.S | 620 |
1 files changed, 620 insertions, 0 deletions
diff --git a/arch/mips/kvm/locore.S b/arch/mips/kvm/locore.S new file mode 100644 index 000000000000..d7279c03c517 --- /dev/null +++ b/arch/mips/kvm/locore.S @@ -0,0 +1,620 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Main entry point for the guest, exception handling. + * + * Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved. + * Authors: Sanjay Lal <sanjayl@kymasys.com> + */ + +#include <asm/asm.h> +#include <asm/asmmacro.h> +#include <asm/regdef.h> +#include <asm/mipsregs.h> +#include <asm/stackframe.h> +#include <asm/asm-offsets.h> + +#define _C_LABEL(x) x +#define MIPSX(name) mips32_ ## name +#define CALLFRAME_SIZ 32 + +/* + * VECTOR + * exception vector entrypoint + */ +#define VECTOR(x, regmask) \ + .ent _C_LABEL(x),0; \ + EXPORT(x); + +#define VECTOR_END(x) \ + EXPORT(x); + +/* Overload, Danger Will Robinson!! */ +#define PT_HOST_ASID PT_BVADDR +#define PT_HOST_USERLOCAL PT_EPC + +#define CP0_DDATA_LO $28,3 +#define CP0_EBASE $15,1 + +#define CP0_INTCTL $12,1 +#define CP0_SRSCTL $12,2 +#define CP0_SRSMAP $12,3 +#define CP0_HWRENA $7,0 + +/* Resume Flags */ +#define RESUME_FLAG_HOST (1<<1) /* Resume host? */ + +#define RESUME_GUEST 0 +#define RESUME_HOST RESUME_FLAG_HOST + +/* + * __kvm_mips_vcpu_run: entry point to the guest + * a0: run + * a1: vcpu + */ + .set noreorder + .set noat + +FEXPORT(__kvm_mips_vcpu_run) + /* k0/k1 not being used in host kernel context */ + INT_ADDIU k1, sp, -PT_SIZE + LONG_S $0, PT_R0(k1) + LONG_S $1, PT_R1(k1) + LONG_S $2, PT_R2(k1) + LONG_S $3, PT_R3(k1) + + LONG_S $4, PT_R4(k1) + LONG_S $5, PT_R5(k1) + LONG_S $6, PT_R6(k1) + LONG_S $7, PT_R7(k1) + + LONG_S $8, PT_R8(k1) + LONG_S $9, PT_R9(k1) + LONG_S $10, PT_R10(k1) + LONG_S $11, PT_R11(k1) + LONG_S $12, PT_R12(k1) + LONG_S $13, PT_R13(k1) + LONG_S $14, PT_R14(k1) + LONG_S $15, PT_R15(k1) + LONG_S $16, PT_R16(k1) + LONG_S $17, PT_R17(k1) + + LONG_S $18, PT_R18(k1) + LONG_S $19, PT_R19(k1) + LONG_S $20, PT_R20(k1) + LONG_S $21, PT_R21(k1) + LONG_S $22, PT_R22(k1) + LONG_S $23, PT_R23(k1) + LONG_S $24, PT_R24(k1) + LONG_S $25, PT_R25(k1) + + /* + * XXXKYMA k0/k1 not saved, not being used if we got here through + * an ioctl() + */ + + LONG_S $28, PT_R28(k1) + LONG_S $29, PT_R29(k1) + LONG_S $30, PT_R30(k1) + LONG_S $31, PT_R31(k1) + + /* Save hi/lo */ + mflo v0 + LONG_S v0, PT_LO(k1) + mfhi v1 + LONG_S v1, PT_HI(k1) + + /* Save host status */ + mfc0 v0, CP0_STATUS + LONG_S v0, PT_STATUS(k1) + + /* Save host ASID, shove it into the BVADDR location */ + mfc0 v1, CP0_ENTRYHI + andi v1, 0xff + LONG_S v1, PT_HOST_ASID(k1) + + /* Save DDATA_LO, will be used to store pointer to vcpu */ + mfc0 v1, CP0_DDATA_LO + LONG_S v1, PT_HOST_USERLOCAL(k1) + + /* DDATA_LO has pointer to vcpu */ + mtc0 a1, CP0_DDATA_LO + + /* Offset into vcpu->arch */ + INT_ADDIU k1, a1, VCPU_HOST_ARCH + + /* + * Save the host stack to VCPU, used for exception processing + * when we exit from the Guest + */ + LONG_S sp, VCPU_HOST_STACK(k1) + + /* Save the kernel gp as well */ + LONG_S gp, VCPU_HOST_GP(k1) + + /* + * Setup status register for running the guest in UM, interrupts + * are disabled + */ + li k0, (ST0_EXL | KSU_USER | ST0_BEV) + mtc0 k0, CP0_STATUS + ehb + + /* load up the new EBASE */ + LONG_L k0, VCPU_GUEST_EBASE(k1) + mtc0 k0, CP0_EBASE + + /* + * Now that the new EBASE has been loaded, unset BEV, set + * interrupt mask as it was but make sure that timer interrupts + * are enabled + */ + li k0, (ST0_EXL | KSU_USER | ST0_IE) + andi v0, v0, ST0_IM + or k0, k0, v0 + mtc0 k0, CP0_STATUS + ehb + + /* Set Guest EPC */ + LONG_L t0, VCPU_PC(k1) + mtc0 t0, CP0_EPC + +FEXPORT(__kvm_mips_load_asid) + /* Set the ASID for the Guest Kernel */ + INT_SLL t0, t0, 1 /* with kseg0 @ 0x40000000, kernel */ + /* addresses shift to 0x80000000 */ + bltz t0, 1f /* If kernel */ + INT_ADDIU t1, k1, VCPU_GUEST_KERNEL_ASID /* (BD) */ + INT_ADDIU t1, k1, VCPU_GUEST_USER_ASID /* else user */ +1: + /* t1: contains the base of the ASID array, need to get the cpu id */ + LONG_L t2, TI_CPU($28) /* smp_processor_id */ + INT_SLL t2, t2, 2 /* x4 */ + REG_ADDU t3, t1, t2 + LONG_L k0, (t3) + andi k0, k0, 0xff + mtc0 k0, CP0_ENTRYHI + ehb + + /* Disable RDHWR access */ + mtc0 zero, CP0_HWRENA + + /* Now load up the Guest Context from VCPU */ + LONG_L $1, VCPU_R1(k1) + LONG_L $2, VCPU_R2(k1) + LONG_L $3, VCPU_R3(k1) + + LONG_L $4, VCPU_R4(k1) + LONG_L $5, VCPU_R5(k1) + LONG_L $6, VCPU_R6(k1) + LONG_L $7, VCPU_R7(k1) + + LONG_L $8, VCPU_R8(k1) + LONG_L $9, VCPU_R9(k1) + LONG_L $10, VCPU_R10(k1) + LONG_L $11, VCPU_R11(k1) + LONG_L $12, VCPU_R12(k1) + LONG_L $13, VCPU_R13(k1) + LONG_L $14, VCPU_R14(k1) + LONG_L $15, VCPU_R15(k1) + LONG_L $16, VCPU_R16(k1) + LONG_L $17, VCPU_R17(k1) + LONG_L $18, VCPU_R18(k1) + LONG_L $19, VCPU_R19(k1) + LONG_L $20, VCPU_R20(k1) + LONG_L $21, VCPU_R21(k1) + LONG_L $22, VCPU_R22(k1) + LONG_L $23, VCPU_R23(k1) + LONG_L $24, VCPU_R24(k1) + LONG_L $25, VCPU_R25(k1) + + /* k0/k1 loaded up later */ + + LONG_L $28, VCPU_R28(k1) + LONG_L $29, VCPU_R29(k1) + LONG_L $30, VCPU_R30(k1) + LONG_L $31, VCPU_R31(k1) + + /* Restore hi/lo */ + LONG_L k0, VCPU_LO(k1) + mtlo k0 + + LONG_L k0, VCPU_HI(k1) + mthi k0 + +FEXPORT(__kvm_mips_load_k0k1) + /* Restore the guest's k0/k1 registers */ + LONG_L k0, VCPU_R26(k1) + LONG_L k1, VCPU_R27(k1) + + /* Jump to guest */ + eret + +VECTOR(MIPSX(exception), unknown) +/* Find out what mode we came from and jump to the proper handler. */ + mtc0 k0, CP0_ERROREPC #01: Save guest k0 + ehb #02: + + mfc0 k0, CP0_EBASE #02: Get EBASE + INT_SRL k0, k0, 10 #03: Get rid of CPUNum + INT_SLL k0, k0, 10 #04 + LONG_S k1, 0x3000(k0) #05: Save k1 @ offset 0x3000 + INT_ADDIU k0, k0, 0x2000 #06: Exception handler is + # installed @ offset 0x2000 + j k0 #07: jump to the function + nop #08: branch delay slot +VECTOR_END(MIPSX(exceptionEnd)) +.end MIPSX(exception) + +/* + * Generic Guest exception handler. We end up here when the guest + * does something that causes a trap to kernel mode. + */ +NESTED (MIPSX(GuestException), CALLFRAME_SIZ, ra) + /* Get the VCPU pointer from DDTATA_LO */ + mfc0 k1, CP0_DDATA_LO + INT_ADDIU k1, k1, VCPU_HOST_ARCH + + /* Start saving Guest context to VCPU */ + LONG_S $0, VCPU_R0(k1) + LONG_S $1, VCPU_R1(k1) + LONG_S $2, VCPU_R2(k1) + LONG_S $3, VCPU_R3(k1) + LONG_S $4, VCPU_R4(k1) + LONG_S $5, VCPU_R5(k1) + LONG_S $6, VCPU_R6(k1) + LONG_S $7, VCPU_R7(k1) + LONG_S $8, VCPU_R8(k1) + LONG_S $9, VCPU_R9(k1) + LONG_S $10, VCPU_R10(k1) + LONG_S $11, VCPU_R11(k1) + LONG_S $12, VCPU_R12(k1) + LONG_S $13, VCPU_R13(k1) + LONG_S $14, VCPU_R14(k1) + LONG_S $15, VCPU_R15(k1) + LONG_S $16, VCPU_R16(k1) + LONG_S $17, VCPU_R17(k1) + LONG_S $18, VCPU_R18(k1) + LONG_S $19, VCPU_R19(k1) + LONG_S $20, VCPU_R20(k1) + LONG_S $21, VCPU_R21(k1) + LONG_S $22, VCPU_R22(k1) + LONG_S $23, VCPU_R23(k1) + LONG_S $24, VCPU_R24(k1) + LONG_S $25, VCPU_R25(k1) + + /* Guest k0/k1 saved later */ + + LONG_S $28, VCPU_R28(k1) + LONG_S $29, VCPU_R29(k1) + LONG_S $30, VCPU_R30(k1) + LONG_S $31, VCPU_R31(k1) + + /* We need to save hi/lo and restore them on the way out */ + mfhi t0 + LONG_S t0, VCPU_HI(k1) + + mflo t0 + LONG_S t0, VCPU_LO(k1) + + /* Finally save guest k0/k1 to VCPU */ + mfc0 t0, CP0_ERROREPC + LONG_S t0, VCPU_R26(k1) + + /* Get GUEST k1 and save it in VCPU */ + PTR_LI t1, ~0x2ff + mfc0 t0, CP0_EBASE + and t0, t0, t1 + LONG_L t0, 0x3000(t0) + LONG_S t0, VCPU_R27(k1) + + /* Now that context has been saved, we can use other registers */ + + /* Restore vcpu */ + mfc0 a1, CP0_DDATA_LO + move s1, a1 + + /* Restore run (vcpu->run) */ + LONG_L a0, VCPU_RUN(a1) + /* Save pointer to run in s0, will be saved by the compiler */ + move s0, a0 + + /* + * Save Host level EPC, BadVaddr and Cause to VCPU, useful to + * process the exception + */ + mfc0 k0,CP0_EPC + LONG_S k0, VCPU_PC(k1) + + mfc0 k0, CP0_BADVADDR + LONG_S k0, VCPU_HOST_CP0_BADVADDR(k1) + + mfc0 k0, CP0_CAUSE + LONG_S k0, VCPU_HOST_CP0_CAUSE(k1) + + mfc0 k0, CP0_ENTRYHI + LONG_S k0, VCPU_HOST_ENTRYHI(k1) + + /* Now restore the host state just enough to run the handlers */ + + /* Swtich EBASE to the one used by Linux */ + /* load up the host EBASE */ + mfc0 v0, CP0_STATUS + + .set at + or k0, v0, ST0_BEV + .set noat + + mtc0 k0, CP0_STATUS + ehb + + LONG_L k0, VCPU_HOST_EBASE(k1) + mtc0 k0,CP0_EBASE + + /* Now that the new EBASE has been loaded, unset BEV and KSU_USER */ + .set at + and v0, v0, ~(ST0_EXL | KSU_USER | ST0_IE) + or v0, v0, ST0_CU0 + .set noat + mtc0 v0, CP0_STATUS + ehb + + /* Load up host GP */ + LONG_L gp, VCPU_HOST_GP(k1) + + /* Need a stack before we can jump to "C" */ + LONG_L sp, VCPU_HOST_STACK(k1) + + /* Saved host state */ + INT_ADDIU sp, sp, -PT_SIZE + + /* + * XXXKYMA do we need to load the host ASID, maybe not because the + * kernel entries are marked GLOBAL, need to verify + */ + + /* Restore host DDATA_LO */ + LONG_L k0, PT_HOST_USERLOCAL(sp) + mtc0 k0, CP0_DDATA_LO + + /* Restore RDHWR access */ + PTR_LI k0, 0x2000000F + mtc0 k0, CP0_HWRENA + + /* Jump to handler */ +FEXPORT(__kvm_mips_jump_to_handler) + /* + * XXXKYMA: not sure if this is safe, how large is the stack?? + * Now jump to the kvm_mips_handle_exit() to see if we can deal + * with this in the kernel + */ + PTR_LA t9, kvm_mips_handle_exit + jalr.hb t9 + INT_ADDIU sp, sp, -CALLFRAME_SIZ /* BD Slot */ + + /* Return from handler Make sure interrupts are disabled */ + di + ehb + + /* + * XXXKYMA: k0/k1 could have been blown away if we processed + * an exception while we were handling the exception from the + * guest, reload k1 + */ + + move k1, s1 + INT_ADDIU k1, k1, VCPU_HOST_ARCH + + /* + * Check return value, should tell us if we are returning to the + * host (handle I/O etc)or resuming the guest + */ + andi t0, v0, RESUME_HOST + bnez t0, __kvm_mips_return_to_host + nop + +__kvm_mips_return_to_guest: + /* Put the saved pointer to vcpu (s1) back into the DDATA_LO Register */ + mtc0 s1, CP0_DDATA_LO + + /* Load up the Guest EBASE to minimize the window where BEV is set */ + LONG_L t0, VCPU_GUEST_EBASE(k1) + + /* Switch EBASE back to the one used by KVM */ + mfc0 v1, CP0_STATUS + .set at + or k0, v1, ST0_BEV + .set noat + mtc0 k0, CP0_STATUS + ehb + mtc0 t0, CP0_EBASE + + /* Setup status register for running guest in UM */ + .set at + or v1, v1, (ST0_EXL | KSU_USER | ST0_IE) + and v1, v1, ~ST0_CU0 + .set noat + mtc0 v1, CP0_STATUS + ehb + + /* Set Guest EPC */ + LONG_L t0, VCPU_PC(k1) + mtc0 t0, CP0_EPC + + /* Set the ASID for the Guest Kernel */ + INT_SLL t0, t0, 1 /* with kseg0 @ 0x40000000, kernel */ + /* addresses shift to 0x80000000 */ + bltz t0, 1f /* If kernel */ + INT_ADDIU t1, k1, VCPU_GUEST_KERNEL_ASID /* (BD) */ + INT_ADDIU t1, k1, VCPU_GUEST_USER_ASID /* else user */ +1: + /* t1: contains the base of the ASID array, need to get the cpu id */ + LONG_L t2, TI_CPU($28) /* smp_processor_id */ + INT_SLL t2, t2, 2 /* x4 */ + REG_ADDU t3, t1, t2 + LONG_L k0, (t3) + andi k0, k0, 0xff + mtc0 k0,CP0_ENTRYHI + ehb + + /* Disable RDHWR access */ + mtc0 zero, CP0_HWRENA + + /* load the guest context from VCPU and return */ + LONG_L $0, VCPU_R0(k1) + LONG_L $1, VCPU_R1(k1) + LONG_L $2, VCPU_R2(k1) + LONG_L $3, VCPU_R3(k1) + LONG_L $4, VCPU_R4(k1) + LONG_L $5, VCPU_R5(k1) + LONG_L $6, VCPU_R6(k1) + LONG_L $7, VCPU_R7(k1) + LONG_L $8, VCPU_R8(k1) + LONG_L $9, VCPU_R9(k1) + LONG_L $10, VCPU_R10(k1) + LONG_L $11, VCPU_R11(k1) + LONG_L $12, VCPU_R12(k1) + LONG_L $13, VCPU_R13(k1) + LONG_L $14, VCPU_R14(k1) + LONG_L $15, VCPU_R15(k1) + LONG_L $16, VCPU_R16(k1) + LONG_L $17, VCPU_R17(k1) + LONG_L $18, VCPU_R18(k1) + LONG_L $19, VCPU_R19(k1) + LONG_L $20, VCPU_R20(k1) + LONG_L $21, VCPU_R21(k1) + LONG_L $22, VCPU_R22(k1) + LONG_L $23, VCPU_R23(k1) + LONG_L $24, VCPU_R24(k1) + LONG_L $25, VCPU_R25(k1) + + /* $/k1 loaded later */ + LONG_L $28, VCPU_R28(k1) + LONG_L $29, VCPU_R29(k1) + LONG_L $30, VCPU_R30(k1) + LONG_L $31, VCPU_R31(k1) + +FEXPORT(__kvm_mips_skip_guest_restore) + LONG_L k0, VCPU_HI(k1) + mthi k0 + + LONG_L k0, VCPU_LO(k1) + mtlo k0 + + LONG_L k0, VCPU_R26(k1) + LONG_L k1, VCPU_R27(k1) + + eret + +__kvm_mips_return_to_host: + /* EBASE is already pointing to Linux */ + LONG_L k1, VCPU_HOST_STACK(k1) + INT_ADDIU k1,k1, -PT_SIZE + + /* Restore host DDATA_LO */ + LONG_L k0, PT_HOST_USERLOCAL(k1) + mtc0 k0, CP0_DDATA_LO + + /* Restore host ASID */ + LONG_L k0, PT_HOST_ASID(sp) + andi k0, 0xff + mtc0 k0,CP0_ENTRYHI + ehb + + /* Load context saved on the host stack */ + LONG_L $0, PT_R0(k1) + LONG_L $1, PT_R1(k1) + + /* + * r2/v0 is the return code, shift it down by 2 (arithmetic) + * to recover the err code + */ + INT_SRA k0, v0, 2 + move $2, k0 + + LONG_L $3, PT_R3(k1) + LONG_L $4, PT_R4(k1) + LONG_L $5, PT_R5(k1) + LONG_L $6, PT_R6(k1) + LONG_L $7, PT_R7(k1) + LONG_L $8, PT_R8(k1) + LONG_L $9, PT_R9(k1) + LONG_L $10, PT_R10(k1) + LONG_L $11, PT_R11(k1) + LONG_L $12, PT_R12(k1) + LONG_L $13, PT_R13(k1) + LONG_L $14, PT_R14(k1) + LONG_L $15, PT_R15(k1) + LONG_L $16, PT_R16(k1) + LONG_L $17, PT_R17(k1) + LONG_L $18, PT_R18(k1) + LONG_L $19, PT_R19(k1) + LONG_L $20, PT_R20(k1) + LONG_L $21, PT_R21(k1) + LONG_L $22, PT_R22(k1) + LONG_L $23, PT_R23(k1) + LONG_L $24, PT_R24(k1) + LONG_L $25, PT_R25(k1) + + /* Host k0/k1 were not saved */ + + LONG_L $28, PT_R28(k1) + LONG_L $29, PT_R29(k1) + LONG_L $30, PT_R30(k1) + + LONG_L k0, PT_HI(k1) + mthi k0 + + LONG_L k0, PT_LO(k1) + mtlo k0 + + /* Restore RDHWR access */ + PTR_LI k0, 0x2000000F + mtc0 k0, CP0_HWRENA + + /* Restore RA, which is the address we will return to */ + LONG_L ra, PT_R31(k1) + j ra + nop + +VECTOR_END(MIPSX(GuestExceptionEnd)) +.end MIPSX(GuestException) + +MIPSX(exceptions): + #### + ##### The exception handlers. + ##### + .word _C_LABEL(MIPSX(GuestException)) # 0 + .word _C_LABEL(MIPSX(GuestException)) # 1 + .word _C_LABEL(MIPSX(GuestException)) # 2 + .word _C_LABEL(MIPSX(GuestException)) # 3 + .word _C_LABEL(MIPSX(GuestException)) # 4 + .word _C_LABEL(MIPSX(GuestException)) # 5 + .word _C_LABEL(MIPSX(GuestException)) # 6 + .word _C_LABEL(MIPSX(GuestException)) # 7 + .word _C_LABEL(MIPSX(GuestException)) # 8 + .word _C_LABEL(MIPSX(GuestException)) # 9 + .word _C_LABEL(MIPSX(GuestException)) # 10 + .word _C_LABEL(MIPSX(GuestException)) # 11 + .word _C_LABEL(MIPSX(GuestException)) # 12 + .word _C_LABEL(MIPSX(GuestException)) # 13 + .word _C_LABEL(MIPSX(GuestException)) # 14 + .word _C_LABEL(MIPSX(GuestException)) # 15 + .word _C_LABEL(MIPSX(GuestException)) # 16 + .word _C_LABEL(MIPSX(GuestException)) # 17 + .word _C_LABEL(MIPSX(GuestException)) # 18 + .word _C_LABEL(MIPSX(GuestException)) # 19 + .word _C_LABEL(MIPSX(GuestException)) # 20 + .word _C_LABEL(MIPSX(GuestException)) # 21 + .word _C_LABEL(MIPSX(GuestException)) # 22 + .word _C_LABEL(MIPSX(GuestException)) # 23 + .word _C_LABEL(MIPSX(GuestException)) # 24 + .word _C_LABEL(MIPSX(GuestException)) # 25 + .word _C_LABEL(MIPSX(GuestException)) # 26 + .word _C_LABEL(MIPSX(GuestException)) # 27 + .word _C_LABEL(MIPSX(GuestException)) # 28 + .word _C_LABEL(MIPSX(GuestException)) # 29 + .word _C_LABEL(MIPSX(GuestException)) # 30 + .word _C_LABEL(MIPSX(GuestException)) # 31 |