root/arch/powerpc/kvm/bookehv_interrupts.S 
/* SPDX-License-Identifier: GPL-2.0-only */
/*
 *
 * Copyright (C) 2010-2011 Freescale Semiconductor, Inc.
 *
 * Author: Varun Sethi <varun.sethi@freescale.com>
 * Author: Scott Wood <scotwood@freescale.com>
 * Author: Mihai Caraman <mihai.caraman@freescale.com>
 *
 * This file is derived from arch/powerpc/kvm/booke_interrupts.S
 */

#include <asm/ppc_asm.h>
#include <asm/kvm_asm.h>
#include <asm/reg.h>
#include <asm/page.h>
#include <asm/asm-compat.h>
#include <asm/asm-offsets.h>
#include <asm/bitsperlong.h>

#ifdef CONFIG_64BIT
#include <asm/exception-64e.h>
#include <asm/hw_irq.h>
#include <asm/irqflags.h>
#else
#include "../kernel/head_booke.h" /* for THREAD_NORMSAVE() */
#endif

#define LONGBYTES               (BITS_PER_LONG / 8)

#define VCPU_GUEST_SPRG(n)      (VCPU_GUEST_SPRGS + (n * LONGBYTES))

/* The host stack layout: */
#define HOST_R1         0 /* Implied by stwu. */
#define HOST_CALLEE_LR  PPC_LR_STKOFF
#define HOST_RUN        (HOST_CALLEE_LR + LONGBYTES)
/*
 * r2 is special: it holds 'current', and it made nonvolatile in the
 * kernel with the -ffixed-r2 gcc option.
 */
#define HOST_R2         (HOST_RUN + LONGBYTES)
#define HOST_CR         (HOST_R2 + LONGBYTES)
#define HOST_NV_GPRS    (HOST_CR + LONGBYTES)
#define __HOST_NV_GPR(n)  (HOST_NV_GPRS + ((n - 14) * LONGBYTES))
#define HOST_NV_GPR(n)  __HOST_NV_GPR(__REG_##n)
#define HOST_MIN_STACK_SIZE (HOST_NV_GPR(R31) + LONGBYTES)
#define HOST_STACK_SIZE ((HOST_MIN_STACK_SIZE + 15) & ~15) /* Align. */
/* LR in caller stack frame. */
#define HOST_STACK_LR   (HOST_STACK_SIZE + PPC_LR_STKOFF)

#define NEED_EMU                0x00000001 /* emulation -- save nv regs */
#define NEED_DEAR               0x00000002 /* save faulting DEAR */
#define NEED_ESR                0x00000004 /* save faulting ESR */

/*
 * On entry:
 * r4 = vcpu, r5 = srr0, r6 = srr1
 * saved in vcpu: cr, ctr, r3-r13
 */
.macro kvm_handler_common intno, srr0, flags
        /* Restore host stack pointer */
        PPC_STL r1, VCPU_GPR(R1)(r4)
        PPC_STL r2, VCPU_GPR(R2)(r4)
        PPC_LL  r1, VCPU_HOST_STACK(r4)
        PPC_LL  r2, HOST_R2(r1)

START_BTB_FLUSH_SECTION
        BTB_FLUSH(r10)
END_BTB_FLUSH_SECTION

        mfspr   r10, SPRN_PID
        lwz     r8, VCPU_HOST_PID(r4)
        PPC_LL  r11, VCPU_SHARED(r4)
        PPC_STL r14, VCPU_GPR(R14)(r4) /* We need a non-volatile GPR. */
        li      r14, \intno

        stw     r10, VCPU_GUEST_PID(r4)
        mtspr   SPRN_PID, r8

#ifdef CONFIG_KVM_EXIT_TIMING
        /* save exit time */
1:      mfspr   r7, SPRN_TBRU
        mfspr   r8, SPRN_TBRL
        mfspr   r9, SPRN_TBRU
        cmpw    r9, r7
        stw     r8, VCPU_TIMING_EXIT_TBL(r4)
        bne-    1b
        stw     r9, VCPU_TIMING_EXIT_TBU(r4)
#endif

        oris    r8, r6, MSR_CE@h
        PPC_STD(r6, VCPU_SHARED_MSR, r11)
        ori     r8, r8, MSR_ME | MSR_RI
        PPC_STL r5, VCPU_PC(r4)

        /*
         * Make sure CE/ME/RI are set (if appropriate for exception type)
         * whether or not the guest had it set.  Since mfmsr/mtmsr are
         * somewhat expensive, skip in the common case where the guest
         * had all these bits set (and thus they're still set if
         * appropriate for the exception type).
         */
        cmpw    r6, r8
        beq     1f
        mfmsr   r7
        .if     \srr0 != SPRN_MCSRR0 && \srr0 != SPRN_CSRR0
        oris    r7, r7, MSR_CE@h
        .endif
        .if     \srr0 != SPRN_MCSRR0
        ori     r7, r7, MSR_ME | MSR_RI
        .endif
        mtmsr   r7
1:

        .if     \flags & NEED_EMU
        PPC_STL r15, VCPU_GPR(R15)(r4)
        PPC_STL r16, VCPU_GPR(R16)(r4)
        PPC_STL r17, VCPU_GPR(R17)(r4)
        PPC_STL r18, VCPU_GPR(R18)(r4)
        PPC_STL r19, VCPU_GPR(R19)(r4)
        PPC_STL r20, VCPU_GPR(R20)(r4)
        PPC_STL r21, VCPU_GPR(R21)(r4)
        PPC_STL r22, VCPU_GPR(R22)(r4)
        PPC_STL r23, VCPU_GPR(R23)(r4)
        PPC_STL r24, VCPU_GPR(R24)(r4)
        PPC_STL r25, VCPU_GPR(R25)(r4)
        PPC_STL r26, VCPU_GPR(R26)(r4)
        PPC_STL r27, VCPU_GPR(R27)(r4)
        PPC_STL r28, VCPU_GPR(R28)(r4)
        PPC_STL r29, VCPU_GPR(R29)(r4)
        PPC_STL r30, VCPU_GPR(R30)(r4)
        PPC_STL r31, VCPU_GPR(R31)(r4)

        /*
         * We don't use external PID support. lwepx faults would need to be
         * handled by KVM and this implies aditional code in DO_KVM (for
         * DTB_MISS, DSI and LRAT) to check ESR[EPID] and EPLC[EGS] which
         * is too intrusive for the host. Get last instuction in
         * kvmppc_get_last_inst().
         */
        li      r9, KVM_INST_FETCH_FAILED
        PPC_STL r9, VCPU_LAST_INST(r4)
        .endif

        .if     \flags & NEED_ESR
        mfspr   r8, SPRN_ESR
        PPC_STL r8, VCPU_FAULT_ESR(r4)
        .endif

        .if     \flags & NEED_DEAR
        mfspr   r9, SPRN_DEAR
        PPC_STL r9, VCPU_FAULT_DEAR(r4)
        .endif

        b       kvmppc_resume_host
.endm

#ifdef CONFIG_64BIT
/* Exception types */
#define EX_GEN                  1
#define EX_GDBELL               2
#define EX_DBG                  3
#define EX_MC                   4
#define EX_CRIT                 5
#define EX_TLB                  6

/*
 * For input register values, see arch/powerpc/include/asm/kvm_booke_hv_asm.h
 */
.macro kvm_handler intno type scratch, paca_ex, ex_r10, ex_r11, srr0, srr1, flags
 _GLOBAL(kvmppc_handler_\intno\()_\srr1)
        mr      r11, r4
        /*
         * Get vcpu from Paca: paca->__current.thread->kvm_vcpu
         */
        PPC_LL  r4, PACACURRENT(r13)
        PPC_LL  r4, (THREAD + THREAD_KVM_VCPU)(r4)
        PPC_STL r10, VCPU_CR(r4)
        PPC_STL r11, VCPU_GPR(R4)(r4)
        PPC_STL r5, VCPU_GPR(R5)(r4)
        PPC_STL r6, VCPU_GPR(R6)(r4)
        PPC_STL r8, VCPU_GPR(R8)(r4)
        PPC_STL r9, VCPU_GPR(R9)(r4)
        .if \type == EX_TLB
        PPC_LL  r5, EX_TLB_R13(r12)
        PPC_LL  r6, EX_TLB_R10(r12)
        PPC_LL  r8, EX_TLB_R11(r12)
        mfspr   r12, \scratch
        .else
        mfspr   r5, \scratch
        PPC_LL  r6, (\paca_ex + \ex_r10)(r13)
        PPC_LL  r8, (\paca_ex + \ex_r11)(r13)
        .endif
        PPC_STL r5, VCPU_GPR(R13)(r4)
        PPC_STL r3, VCPU_GPR(R3)(r4)
        PPC_STL r7, VCPU_GPR(R7)(r4)
        PPC_STL r12, VCPU_GPR(R12)(r4)
        PPC_STL r6, VCPU_GPR(R10)(r4)
        PPC_STL r8, VCPU_GPR(R11)(r4)
        mfctr   r5
        PPC_STL r5, VCPU_CTR(r4)
        mfspr   r5, \srr0
        mfspr   r6, \srr1
        kvm_handler_common \intno, \srr0, \flags
.endm

#define EX_PARAMS(type) \
        EX_##type, \
        SPRN_SPRG_##type##_SCRATCH, \
        PACA_EX##type, \
        EX_R10, \
        EX_R11

#define EX_PARAMS_TLB \
        EX_TLB, \
        SPRN_SPRG_GEN_SCRATCH, \
        PACA_EXTLB, \
        EX_TLB_R10, \
        EX_TLB_R11

kvm_handler BOOKE_INTERRUPT_CRITICAL, EX_PARAMS(CRIT), \
        SPRN_CSRR0, SPRN_CSRR1, 0
kvm_handler BOOKE_INTERRUPT_MACHINE_CHECK, EX_PARAMS(MC), \
        SPRN_MCSRR0, SPRN_MCSRR1, 0
kvm_handler BOOKE_INTERRUPT_DATA_STORAGE, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1,(NEED_EMU | NEED_DEAR | NEED_ESR)
kvm_handler BOOKE_INTERRUPT_INST_STORAGE, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1, NEED_ESR
kvm_handler BOOKE_INTERRUPT_EXTERNAL, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_ALIGNMENT, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1,(NEED_DEAR | NEED_ESR)
kvm_handler BOOKE_INTERRUPT_PROGRAM, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1, (NEED_ESR | NEED_EMU)
kvm_handler BOOKE_INTERRUPT_FP_UNAVAIL, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_AP_UNAVAIL, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_DECREMENTER, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_FIT, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_WATCHDOG, EX_PARAMS(CRIT),\
        SPRN_CSRR0, SPRN_CSRR1, 0
/*
 * Only bolted TLB miss exception handlers are supported for now
 */
kvm_handler BOOKE_INTERRUPT_DTLB_MISS, EX_PARAMS_TLB, \
        SPRN_SRR0, SPRN_SRR1, (NEED_EMU | NEED_DEAR | NEED_ESR)
kvm_handler BOOKE_INTERRUPT_ITLB_MISS, EX_PARAMS_TLB, \
        SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_ALTIVEC_UNAVAIL, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_ALTIVEC_ASSIST, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_PERFORMANCE_MONITOR, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_DOORBELL, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_DOORBELL_CRITICAL, EX_PARAMS(CRIT), \
        SPRN_CSRR0, SPRN_CSRR1, 0
kvm_handler BOOKE_INTERRUPT_HV_PRIV, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1, NEED_EMU
kvm_handler BOOKE_INTERRUPT_HV_SYSCALL, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_GUEST_DBELL, EX_PARAMS(GDBELL), \
        SPRN_GSRR0, SPRN_GSRR1, 0
kvm_handler BOOKE_INTERRUPT_GUEST_DBELL_CRIT, EX_PARAMS(CRIT), \
        SPRN_CSRR0, SPRN_CSRR1, 0
kvm_handler BOOKE_INTERRUPT_DEBUG, EX_PARAMS(DBG), \
        SPRN_DSRR0, SPRN_DSRR1, 0
kvm_handler BOOKE_INTERRUPT_DEBUG, EX_PARAMS(CRIT), \
        SPRN_CSRR0, SPRN_CSRR1, 0
kvm_handler BOOKE_INTERRUPT_LRAT_ERROR, EX_PARAMS(GEN), \
        SPRN_SRR0, SPRN_SRR1, (NEED_EMU | NEED_DEAR | NEED_ESR)
#else
/*
 * For input register values, see arch/powerpc/include/asm/kvm_booke_hv_asm.h
 */
.macro kvm_handler intno srr0, srr1, flags
_GLOBAL(kvmppc_handler_\intno\()_\srr1)
        PPC_LL  r11, THREAD_KVM_VCPU(r10)
        PPC_STL r3, VCPU_GPR(R3)(r11)
        mfspr   r3, SPRN_SPRG_RSCRATCH0
        PPC_STL r4, VCPU_GPR(R4)(r11)
        PPC_LL  r4, THREAD_NORMSAVE(0)(r10)
        PPC_STL r5, VCPU_GPR(R5)(r11)
        PPC_STL r13, VCPU_CR(r11)
        mfspr   r5, \srr0
        PPC_STL r3, VCPU_GPR(R10)(r11)
        PPC_LL  r3, THREAD_NORMSAVE(2)(r10)
        PPC_STL r6, VCPU_GPR(R6)(r11)
        PPC_STL r4, VCPU_GPR(R11)(r11)
        mfspr   r6, \srr1
        PPC_STL r7, VCPU_GPR(R7)(r11)
        PPC_STL r8, VCPU_GPR(R8)(r11)
        PPC_STL r9, VCPU_GPR(R9)(r11)
        PPC_STL r3, VCPU_GPR(R13)(r11)
        mfctr   r7
        PPC_STL r12, VCPU_GPR(R12)(r11)
        PPC_STL r7, VCPU_CTR(r11)
        mr      r4, r11
        kvm_handler_common \intno, \srr0, \flags
.endm

.macro kvm_lvl_handler intno scratch srr0, srr1, flags
_GLOBAL(kvmppc_handler_\intno\()_\srr1)
        mfspr   r10, SPRN_SPRG_THREAD
        PPC_LL  r11, THREAD_KVM_VCPU(r10)
        PPC_STL r3, VCPU_GPR(R3)(r11)
        mfspr   r3, \scratch
        PPC_STL r4, VCPU_GPR(R4)(r11)
        PPC_LL  r4, GPR9(r8)
        PPC_STL r5, VCPU_GPR(R5)(r11)
        PPC_STL r9, VCPU_CR(r11)
        mfspr   r5, \srr0
        PPC_STL r3, VCPU_GPR(R8)(r11)
        PPC_LL  r3, GPR10(r8)
        PPC_STL r6, VCPU_GPR(R6)(r11)
        PPC_STL r4, VCPU_GPR(R9)(r11)
        mfspr   r6, \srr1
        PPC_LL  r4, GPR11(r8)
        PPC_STL r7, VCPU_GPR(R7)(r11)
        PPC_STL r3, VCPU_GPR(R10)(r11)
        mfctr   r7
        PPC_STL r12, VCPU_GPR(R12)(r11)
        PPC_STL r13, VCPU_GPR(R13)(r11)
        PPC_STL r4, VCPU_GPR(R11)(r11)
        PPC_STL r7, VCPU_CTR(r11)
        mr      r4, r11
        kvm_handler_common \intno, \srr0, \flags
.endm

kvm_lvl_handler BOOKE_INTERRUPT_CRITICAL, \
        SPRN_SPRG_RSCRATCH_CRIT, SPRN_CSRR0, SPRN_CSRR1, 0
kvm_lvl_handler BOOKE_INTERRUPT_MACHINE_CHECK, \
        SPRN_SPRG_RSCRATCH_MC, SPRN_MCSRR0, SPRN_MCSRR1, 0
kvm_handler BOOKE_INTERRUPT_DATA_STORAGE, \
        SPRN_SRR0, SPRN_SRR1, (NEED_EMU | NEED_DEAR | NEED_ESR)
kvm_handler BOOKE_INTERRUPT_INST_STORAGE, SPRN_SRR0, SPRN_SRR1, NEED_ESR
kvm_handler BOOKE_INTERRUPT_EXTERNAL, SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_ALIGNMENT, \
        SPRN_SRR0, SPRN_SRR1, (NEED_DEAR | NEED_ESR)
kvm_handler BOOKE_INTERRUPT_PROGRAM, SPRN_SRR0, SPRN_SRR1, (NEED_ESR | NEED_EMU)
kvm_handler BOOKE_INTERRUPT_FP_UNAVAIL, SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_SYSCALL, SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_AP_UNAVAIL, SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_DECREMENTER, SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_FIT, SPRN_SRR0, SPRN_SRR1, 0
kvm_lvl_handler BOOKE_INTERRUPT_WATCHDOG, \
        SPRN_SPRG_RSCRATCH_CRIT, SPRN_CSRR0, SPRN_CSRR1, 0
kvm_handler BOOKE_INTERRUPT_DTLB_MISS, \
        SPRN_SRR0, SPRN_SRR1, (NEED_EMU | NEED_DEAR | NEED_ESR)
kvm_handler BOOKE_INTERRUPT_ITLB_MISS, SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_PERFORMANCE_MONITOR, SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_DOORBELL, SPRN_SRR0, SPRN_SRR1, 0
kvm_lvl_handler BOOKE_INTERRUPT_DOORBELL_CRITICAL, \
        SPRN_SPRG_RSCRATCH_CRIT, SPRN_CSRR0, SPRN_CSRR1, 0
kvm_handler BOOKE_INTERRUPT_HV_PRIV, SPRN_SRR0, SPRN_SRR1, NEED_EMU
kvm_handler BOOKE_INTERRUPT_HV_SYSCALL, SPRN_SRR0, SPRN_SRR1, 0
kvm_handler BOOKE_INTERRUPT_GUEST_DBELL, SPRN_GSRR0, SPRN_GSRR1, 0
kvm_lvl_handler BOOKE_INTERRUPT_GUEST_DBELL_CRIT, \
        SPRN_SPRG_RSCRATCH_CRIT, SPRN_CSRR0, SPRN_CSRR1, 0
kvm_lvl_handler BOOKE_INTERRUPT_DEBUG, \
        SPRN_SPRG_RSCRATCH_CRIT, SPRN_CSRR0, SPRN_CSRR1, 0
kvm_lvl_handler BOOKE_INTERRUPT_DEBUG, \
        SPRN_SPRG_RSCRATCH_DBG, SPRN_DSRR0, SPRN_DSRR1, 0
#endif

/* Registers:
 *  SPRG_SCRATCH0: guest r10
 *  r4: vcpu pointer
 *  r11: vcpu->arch.shared
 *  r14: KVM exit number
 */
_GLOBAL(kvmppc_resume_host)
        /* Save remaining volatile guest register state to vcpu. */
        mfspr   r3, SPRN_VRSAVE
        PPC_STL r0, VCPU_GPR(R0)(r4)
        mflr    r5
        mfspr   r6, SPRN_SPRG4
        PPC_STL r5, VCPU_LR(r4)
        mfspr   r7, SPRN_SPRG5
        stw     r3, VCPU_VRSAVE(r4)
#ifdef CONFIG_64BIT
        PPC_LL  r3, PACA_SPRG_VDSO(r13)
#endif
        mfspr   r5, SPRN_SPRG9
        PPC_STD(r6, VCPU_SHARED_SPRG4, r11)
        mfspr   r8, SPRN_SPRG6
        PPC_STD(r7, VCPU_SHARED_SPRG5, r11)
        mfspr   r9, SPRN_SPRG7
#ifdef CONFIG_64BIT
        mtspr   SPRN_SPRG_VDSO_WRITE, r3
#endif
        PPC_STD(r5, VCPU_SPRG9, r4)
        PPC_STD(r8, VCPU_SHARED_SPRG6, r11)
        mfxer   r3
        PPC_STD(r9, VCPU_SHARED_SPRG7, r11)

        /* save guest MAS registers and restore host mas4 & mas6 */
        mfspr   r5, SPRN_MAS0
        PPC_STL r3, VCPU_XER(r4)
        mfspr   r6, SPRN_MAS1
        stw     r5, VCPU_SHARED_MAS0(r11)
        mfspr   r7, SPRN_MAS2
        stw     r6, VCPU_SHARED_MAS1(r11)
        PPC_STD(r7, VCPU_SHARED_MAS2, r11)
        mfspr   r5, SPRN_MAS3
        mfspr   r6, SPRN_MAS4
        stw     r5, VCPU_SHARED_MAS7_3+4(r11)
        mfspr   r7, SPRN_MAS6
        stw     r6, VCPU_SHARED_MAS4(r11)
        mfspr   r5, SPRN_MAS7
        lwz     r6, VCPU_HOST_MAS4(r4)
        stw     r7, VCPU_SHARED_MAS6(r11)
        lwz     r8, VCPU_HOST_MAS6(r4)
        mtspr   SPRN_MAS4, r6
        stw     r5, VCPU_SHARED_MAS7_3+0(r11)
        mtspr   SPRN_MAS6, r8
        /* Enable MAS register updates via exception */
        mfspr   r3, SPRN_EPCR
        rlwinm  r3, r3, 0, ~SPRN_EPCR_DMIUH
        mtspr   SPRN_EPCR, r3
        isync

        /* Switch to kernel stack and jump to handler. */
        mr      r3, r4
        mr      r5, r14 /* intno */
        mr      r14, r4 /* Save vcpu pointer. */
        mr      r4, r5
        bl      kvmppc_handle_exit

        /* Restore vcpu pointer and the nonvolatiles we used. */
        mr      r4, r14
        PPC_LL  r14, VCPU_GPR(R14)(r4)

        andi.   r5, r3, RESUME_FLAG_NV
        beq     skip_nv_load
        PPC_LL  r15, VCPU_GPR(R15)(r4)
        PPC_LL  r16, VCPU_GPR(R16)(r4)
        PPC_LL  r17, VCPU_GPR(R17)(r4)
        PPC_LL  r18, VCPU_GPR(R18)(r4)
        PPC_LL  r19, VCPU_GPR(R19)(r4)
        PPC_LL  r20, VCPU_GPR(R20)(r4)
        PPC_LL  r21, VCPU_GPR(R21)(r4)
        PPC_LL  r22, VCPU_GPR(R22)(r4)
        PPC_LL  r23, VCPU_GPR(R23)(r4)
        PPC_LL  r24, VCPU_GPR(R24)(r4)
        PPC_LL  r25, VCPU_GPR(R25)(r4)
        PPC_LL  r26, VCPU_GPR(R26)(r4)
        PPC_LL  r27, VCPU_GPR(R27)(r4)
        PPC_LL  r28, VCPU_GPR(R28)(r4)
        PPC_LL  r29, VCPU_GPR(R29)(r4)
        PPC_LL  r30, VCPU_GPR(R30)(r4)
        PPC_LL  r31, VCPU_GPR(R31)(r4)
skip_nv_load:
        /* Should we return to the guest? */
        andi.   r5, r3, RESUME_FLAG_HOST
        beq     lightweight_exit

        srawi   r3, r3, 2 /* Shift -ERR back down. */

heavyweight_exit:
        /* Not returning to guest. */
        PPC_LL  r5, HOST_STACK_LR(r1)
        lwz     r6, HOST_CR(r1)

        /*
         * We already saved guest volatile register state; now save the
         * non-volatiles.
         */

        PPC_STL r15, VCPU_GPR(R15)(r4)
        PPC_STL r16, VCPU_GPR(R16)(r4)
        PPC_STL r17, VCPU_GPR(R17)(r4)
        PPC_STL r18, VCPU_GPR(R18)(r4)
        PPC_STL r19, VCPU_GPR(R19)(r4)
        PPC_STL r20, VCPU_GPR(R20)(r4)
        PPC_STL r21, VCPU_GPR(R21)(r4)
        PPC_STL r22, VCPU_GPR(R22)(r4)
        PPC_STL r23, VCPU_GPR(R23)(r4)
        PPC_STL r24, VCPU_GPR(R24)(r4)
        PPC_STL r25, VCPU_GPR(R25)(r4)
        PPC_STL r26, VCPU_GPR(R26)(r4)
        PPC_STL r27, VCPU_GPR(R27)(r4)
        PPC_STL r28, VCPU_GPR(R28)(r4)
        PPC_STL r29, VCPU_GPR(R29)(r4)
        PPC_STL r30, VCPU_GPR(R30)(r4)
        PPC_STL r31, VCPU_GPR(R31)(r4)

        /* Load host non-volatile register state from host stack. */
        PPC_LL  r14, HOST_NV_GPR(R14)(r1)
        PPC_LL  r15, HOST_NV_GPR(R15)(r1)
        PPC_LL  r16, HOST_NV_GPR(R16)(r1)
        PPC_LL  r17, HOST_NV_GPR(R17)(r1)
        PPC_LL  r18, HOST_NV_GPR(R18)(r1)
        PPC_LL  r19, HOST_NV_GPR(R19)(r1)
        PPC_LL  r20, HOST_NV_GPR(R20)(r1)
        PPC_LL  r21, HOST_NV_GPR(R21)(r1)
        PPC_LL  r22, HOST_NV_GPR(R22)(r1)
        PPC_LL  r23, HOST_NV_GPR(R23)(r1)
        PPC_LL  r24, HOST_NV_GPR(R24)(r1)
        PPC_LL  r25, HOST_NV_GPR(R25)(r1)
        PPC_LL  r26, HOST_NV_GPR(R26)(r1)
        PPC_LL  r27, HOST_NV_GPR(R27)(r1)
        PPC_LL  r28, HOST_NV_GPR(R28)(r1)
        PPC_LL  r29, HOST_NV_GPR(R29)(r1)
        PPC_LL  r30, HOST_NV_GPR(R30)(r1)
        PPC_LL  r31, HOST_NV_GPR(R31)(r1)

        /* Return to kvm_vcpu_run(). */
        mtlr    r5
        mtcr    r6
        addi    r1, r1, HOST_STACK_SIZE
        /* r3 still contains the return code from kvmppc_handle_exit(). */
        blr

/* Registers:
 *  r3: vcpu pointer
 */
_GLOBAL(__kvmppc_vcpu_run)
        stwu    r1, -HOST_STACK_SIZE(r1)
        PPC_STL r1, VCPU_HOST_STACK(r3) /* Save stack pointer to vcpu. */

        /* Save host state to stack. */
        mr      r4, r3
        mflr    r3
        mfcr    r5
        PPC_STL r3, HOST_STACK_LR(r1)

        stw     r5, HOST_CR(r1)

        /* Save host non-volatile register state to stack. */
        PPC_STL r14, HOST_NV_GPR(R14)(r1)
        PPC_STL r15, HOST_NV_GPR(R15)(r1)
        PPC_STL r16, HOST_NV_GPR(R16)(r1)
        PPC_STL r17, HOST_NV_GPR(R17)(r1)
        PPC_STL r18, HOST_NV_GPR(R18)(r1)
        PPC_STL r19, HOST_NV_GPR(R19)(r1)
        PPC_STL r20, HOST_NV_GPR(R20)(r1)
        PPC_STL r21, HOST_NV_GPR(R21)(r1)
        PPC_STL r22, HOST_NV_GPR(R22)(r1)
        PPC_STL r23, HOST_NV_GPR(R23)(r1)
        PPC_STL r24, HOST_NV_GPR(R24)(r1)
        PPC_STL r25, HOST_NV_GPR(R25)(r1)
        PPC_STL r26, HOST_NV_GPR(R26)(r1)
        PPC_STL r27, HOST_NV_GPR(R27)(r1)
        PPC_STL r28, HOST_NV_GPR(R28)(r1)
        PPC_STL r29, HOST_NV_GPR(R29)(r1)
        PPC_STL r30, HOST_NV_GPR(R30)(r1)
        PPC_STL r31, HOST_NV_GPR(R31)(r1)

        /* Load guest non-volatiles. */
        PPC_LL  r14, VCPU_GPR(R14)(r4)
        PPC_LL  r15, VCPU_GPR(R15)(r4)
        PPC_LL  r16, VCPU_GPR(R16)(r4)
        PPC_LL  r17, VCPU_GPR(R17)(r4)
        PPC_LL  r18, VCPU_GPR(R18)(r4)
        PPC_LL  r19, VCPU_GPR(R19)(r4)
        PPC_LL  r20, VCPU_GPR(R20)(r4)
        PPC_LL  r21, VCPU_GPR(R21)(r4)
        PPC_LL  r22, VCPU_GPR(R22)(r4)
        PPC_LL  r23, VCPU_GPR(R23)(r4)
        PPC_LL  r24, VCPU_GPR(R24)(r4)
        PPC_LL  r25, VCPU_GPR(R25)(r4)
        PPC_LL  r26, VCPU_GPR(R26)(r4)
        PPC_LL  r27, VCPU_GPR(R27)(r4)
        PPC_LL  r28, VCPU_GPR(R28)(r4)
        PPC_LL  r29, VCPU_GPR(R29)(r4)
        PPC_LL  r30, VCPU_GPR(R30)(r4)
        PPC_LL  r31, VCPU_GPR(R31)(r4)


lightweight_exit:
        PPC_STL r2, HOST_R2(r1)

        mfspr   r3, SPRN_PID
        stw     r3, VCPU_HOST_PID(r4)
        lwz     r3, VCPU_GUEST_PID(r4)
        mtspr   SPRN_PID, r3

        PPC_LL  r11, VCPU_SHARED(r4)
        /* Disable MAS register updates via exception */
        mfspr   r3, SPRN_EPCR
        oris    r3, r3, SPRN_EPCR_DMIUH@h
        mtspr   SPRN_EPCR, r3
        isync
        /* Save host mas4 and mas6 and load guest MAS registers */
        mfspr   r3, SPRN_MAS4
        stw     r3, VCPU_HOST_MAS4(r4)
        mfspr   r3, SPRN_MAS6
        stw     r3, VCPU_HOST_MAS6(r4)
        lwz     r3, VCPU_SHARED_MAS0(r11)
        lwz     r5, VCPU_SHARED_MAS1(r11)
        PPC_LD(r6, VCPU_SHARED_MAS2, r11)
        lwz     r7, VCPU_SHARED_MAS7_3+4(r11)
        lwz     r8, VCPU_SHARED_MAS4(r11)
        mtspr   SPRN_MAS0, r3
        mtspr   SPRN_MAS1, r5
        mtspr   SPRN_MAS2, r6
        mtspr   SPRN_MAS3, r7
        mtspr   SPRN_MAS4, r8
        lwz     r3, VCPU_SHARED_MAS6(r11)
        lwz     r5, VCPU_SHARED_MAS7_3+0(r11)
        mtspr   SPRN_MAS6, r3
        mtspr   SPRN_MAS7, r5

        /*
         * Host interrupt handlers may have clobbered these guest-readable
         * SPRGs, so we need to reload them here with the guest's values.
         */
        lwz     r3, VCPU_VRSAVE(r4)
        PPC_LD(r5, VCPU_SHARED_SPRG4, r11)
        mtspr   SPRN_VRSAVE, r3
        PPC_LD(r6, VCPU_SHARED_SPRG5, r11)
        mtspr   SPRN_SPRG4W, r5
        PPC_LD(r7, VCPU_SHARED_SPRG6, r11)
        mtspr   SPRN_SPRG5W, r6
        PPC_LD(r8, VCPU_SHARED_SPRG7, r11)
        mtspr   SPRN_SPRG6W, r7
        PPC_LD(r5, VCPU_SPRG9, r4)
        mtspr   SPRN_SPRG7W, r8
        mtspr   SPRN_SPRG9, r5

        /* Load some guest volatiles. */
        PPC_LL  r3, VCPU_LR(r4)
        PPC_LL  r5, VCPU_XER(r4)
        PPC_LL  r6, VCPU_CTR(r4)
        PPC_LL  r7, VCPU_CR(r4)
        PPC_LL  r8, VCPU_PC(r4)
        PPC_LD(r9, VCPU_SHARED_MSR, r11)
        PPC_LL  r0, VCPU_GPR(R0)(r4)
        PPC_LL  r1, VCPU_GPR(R1)(r4)
        PPC_LL  r2, VCPU_GPR(R2)(r4)
        PPC_LL  r10, VCPU_GPR(R10)(r4)
        PPC_LL  r11, VCPU_GPR(R11)(r4)
        PPC_LL  r12, VCPU_GPR(R12)(r4)
        PPC_LL  r13, VCPU_GPR(R13)(r4)
        mtlr    r3
        mtxer   r5
        mtctr   r6
        mtsrr0  r8
        mtsrr1  r9

#ifdef CONFIG_KVM_EXIT_TIMING
        /* save enter time */
1:
        mfspr   r6, SPRN_TBRU
        mfspr   r9, SPRN_TBRL
        mfspr   r8, SPRN_TBRU
        cmpw    r8, r6
        stw     r9, VCPU_TIMING_LAST_ENTER_TBL(r4)
        bne     1b
        stw     r8, VCPU_TIMING_LAST_ENTER_TBU(r4)
#endif

        /*
         * Don't execute any instruction which can change CR after
         * below instruction.
         */
        mtcr    r7

        /* Finish loading guest volatiles and jump to guest. */
        PPC_LL  r5, VCPU_GPR(R5)(r4)
        PPC_LL  r6, VCPU_GPR(R6)(r4)
        PPC_LL  r7, VCPU_GPR(R7)(r4)
        PPC_LL  r8, VCPU_GPR(R8)(r4)
        PPC_LL  r9, VCPU_GPR(R9)(r4)

        PPC_LL  r3, VCPU_GPR(R3)(r4)
        PPC_LL  r4, VCPU_GPR(R4)(r4)
        rfi