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d825a04387
We call a C helper to save all svcpu fields into our vcpu. The C ABI states that r12 is considered volatile. However, we keep our exit handler id in r12 currently. So we need to save it away into a non-volatile register instead that definitely does get preserved across the C call. This bug usually didn't hit anyone yet since gcc is smart enough to generate code that doesn't even need r12 which means it stayed identical throughout the call by sheer luck. But we can't rely on that. Signed-off-by: Alexander Graf <agraf@suse.de>
234 lines
5.9 KiB
ArmAsm
234 lines
5.9 KiB
ArmAsm
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License, version 2, as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* Copyright SUSE Linux Products GmbH 2009
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*
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* Authors: Alexander Graf <agraf@suse.de>
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*/
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#include <asm/ppc_asm.h>
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#include <asm/kvm_asm.h>
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#include <asm/reg.h>
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#include <asm/page.h>
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#include <asm/asm-offsets.h>
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#include <asm/exception-64s.h>
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#if defined(CONFIG_PPC_BOOK3S_64)
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#define FUNC(name) GLUE(.,name)
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#define GET_SHADOW_VCPU(reg) addi reg, r13, PACA_SVCPU
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#elif defined(CONFIG_PPC_BOOK3S_32)
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#define FUNC(name) name
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#define GET_SHADOW_VCPU(reg) lwz reg, (THREAD + THREAD_KVM_SVCPU)(r2)
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#endif /* CONFIG_PPC_BOOK3S_XX */
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#define VCPU_LOAD_NVGPRS(vcpu) \
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PPC_LL r14, VCPU_GPR(R14)(vcpu); \
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PPC_LL r15, VCPU_GPR(R15)(vcpu); \
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PPC_LL r16, VCPU_GPR(R16)(vcpu); \
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PPC_LL r17, VCPU_GPR(R17)(vcpu); \
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PPC_LL r18, VCPU_GPR(R18)(vcpu); \
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PPC_LL r19, VCPU_GPR(R19)(vcpu); \
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PPC_LL r20, VCPU_GPR(R20)(vcpu); \
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PPC_LL r21, VCPU_GPR(R21)(vcpu); \
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PPC_LL r22, VCPU_GPR(R22)(vcpu); \
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PPC_LL r23, VCPU_GPR(R23)(vcpu); \
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PPC_LL r24, VCPU_GPR(R24)(vcpu); \
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PPC_LL r25, VCPU_GPR(R25)(vcpu); \
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PPC_LL r26, VCPU_GPR(R26)(vcpu); \
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PPC_LL r27, VCPU_GPR(R27)(vcpu); \
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PPC_LL r28, VCPU_GPR(R28)(vcpu); \
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PPC_LL r29, VCPU_GPR(R29)(vcpu); \
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PPC_LL r30, VCPU_GPR(R30)(vcpu); \
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PPC_LL r31, VCPU_GPR(R31)(vcpu); \
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/*****************************************************************************
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* *
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* Guest entry / exit code that is in kernel module memory (highmem) *
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* *
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****************************************************************************/
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/* Registers:
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* r3: kvm_run pointer
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* r4: vcpu pointer
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*/
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_GLOBAL(__kvmppc_vcpu_run)
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kvm_start_entry:
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/* Write correct stack frame */
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mflr r0
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PPC_STL r0,PPC_LR_STKOFF(r1)
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/* Save host state to the stack */
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PPC_STLU r1, -SWITCH_FRAME_SIZE(r1)
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/* Save r3 (kvm_run) and r4 (vcpu) */
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SAVE_2GPRS(3, r1)
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/* Save non-volatile registers (r14 - r31) */
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SAVE_NVGPRS(r1)
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/* Save CR */
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mfcr r14
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stw r14, _CCR(r1)
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/* Save LR */
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PPC_STL r0, _LINK(r1)
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/* Load non-volatile guest state from the vcpu */
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VCPU_LOAD_NVGPRS(r4)
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kvm_start_lightweight:
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/* Copy registers into shadow vcpu so we can access them in real mode */
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GET_SHADOW_VCPU(r3)
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bl FUNC(kvmppc_copy_to_svcpu)
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nop
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REST_GPR(4, r1)
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#ifdef CONFIG_PPC_BOOK3S_64
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/* Get the dcbz32 flag */
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PPC_LL r3, VCPU_HFLAGS(r4)
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rldicl r3, r3, 0, 63 /* r3 &= 1 */
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stb r3, HSTATE_RESTORE_HID5(r13)
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/* Load up guest SPRG3 value, since it's user readable */
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ld r3, VCPU_SHARED(r4)
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ld r3, VCPU_SHARED_SPRG3(r3)
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mtspr SPRN_SPRG3, r3
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#endif /* CONFIG_PPC_BOOK3S_64 */
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PPC_LL r4, VCPU_SHADOW_MSR(r4) /* get shadow_msr */
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/* Jump to segment patching handler and into our guest */
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bl FUNC(kvmppc_entry_trampoline)
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nop
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/*
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* This is the handler in module memory. It gets jumped at from the
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* lowmem trampoline code, so it's basically the guest exit code.
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*
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*/
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/*
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* Register usage at this point:
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*
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* R1 = host R1
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* R2 = host R2
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* R12 = exit handler id
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* R13 = PACA
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* SVCPU.* = guest *
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*
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*/
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PPC_LL r3, GPR4(r1) /* vcpu pointer */
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/*
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* kvmppc_copy_from_svcpu can clobber volatile registers, save
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* the exit handler id to the vcpu and restore it from there later.
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*/
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stw r12, VCPU_TRAP(r3)
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/* Transfer reg values from shadow vcpu back to vcpu struct */
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/* On 64-bit, interrupts are still off at this point */
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GET_SHADOW_VCPU(r4)
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bl FUNC(kvmppc_copy_from_svcpu)
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nop
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#ifdef CONFIG_PPC_BOOK3S_64
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/* Re-enable interrupts */
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ld r3, HSTATE_HOST_MSR(r13)
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ori r3, r3, MSR_EE
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MTMSR_EERI(r3)
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/*
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* Reload kernel SPRG3 value.
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* No need to save guest value as usermode can't modify SPRG3.
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*/
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ld r3, PACA_SPRG3(r13)
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mtspr SPRN_SPRG3, r3
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#endif /* CONFIG_PPC_BOOK3S_64 */
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/* R7 = vcpu */
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PPC_LL r7, GPR4(r1)
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PPC_STL r14, VCPU_GPR(R14)(r7)
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PPC_STL r15, VCPU_GPR(R15)(r7)
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PPC_STL r16, VCPU_GPR(R16)(r7)
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PPC_STL r17, VCPU_GPR(R17)(r7)
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PPC_STL r18, VCPU_GPR(R18)(r7)
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PPC_STL r19, VCPU_GPR(R19)(r7)
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PPC_STL r20, VCPU_GPR(R20)(r7)
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PPC_STL r21, VCPU_GPR(R21)(r7)
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PPC_STL r22, VCPU_GPR(R22)(r7)
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PPC_STL r23, VCPU_GPR(R23)(r7)
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PPC_STL r24, VCPU_GPR(R24)(r7)
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PPC_STL r25, VCPU_GPR(R25)(r7)
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PPC_STL r26, VCPU_GPR(R26)(r7)
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PPC_STL r27, VCPU_GPR(R27)(r7)
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PPC_STL r28, VCPU_GPR(R28)(r7)
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PPC_STL r29, VCPU_GPR(R29)(r7)
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PPC_STL r30, VCPU_GPR(R30)(r7)
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PPC_STL r31, VCPU_GPR(R31)(r7)
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/* Pass the exit number as 3rd argument to kvmppc_handle_exit */
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lwz r5, VCPU_TRAP(r7)
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/* Restore r3 (kvm_run) and r4 (vcpu) */
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REST_2GPRS(3, r1)
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bl FUNC(kvmppc_handle_exit_pr)
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/* If RESUME_GUEST, get back in the loop */
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cmpwi r3, RESUME_GUEST
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beq kvm_loop_lightweight
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cmpwi r3, RESUME_GUEST_NV
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beq kvm_loop_heavyweight
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kvm_exit_loop:
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PPC_LL r4, _LINK(r1)
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mtlr r4
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lwz r14, _CCR(r1)
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mtcr r14
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/* Restore non-volatile host registers (r14 - r31) */
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REST_NVGPRS(r1)
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addi r1, r1, SWITCH_FRAME_SIZE
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blr
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kvm_loop_heavyweight:
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PPC_LL r4, _LINK(r1)
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PPC_STL r4, (PPC_LR_STKOFF + SWITCH_FRAME_SIZE)(r1)
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/* Load vcpu and cpu_run */
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REST_2GPRS(3, r1)
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/* Load non-volatile guest state from the vcpu */
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VCPU_LOAD_NVGPRS(r4)
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/* Jump back into the beginning of this function */
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b kvm_start_lightweight
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kvm_loop_lightweight:
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/* We'll need the vcpu pointer */
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REST_GPR(4, r1)
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/* Jump back into the beginning of this function */
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b kvm_start_lightweight
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