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Unlike the other general-purpose SPRs, SPRG3 can be read by usermode code, and is used in recent kernels to store the CPU and NUMA node numbers so that they can be read by VDSO functions. Thus we need to load the guest's SPRG3 value into the real SPRG3 register when entering the guest, and restore the host's value when exiting the guest. We don't need to save the guest SPRG3 value when exiting the guest as usermode code can't modify SPRG3. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
208 lines
5.2 KiB
ArmAsm
208 lines
5.2 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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#elif defined(CONFIG_PPC_BOOK3S_32)
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#define FUNC(name) name
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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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#ifdef CONFIG_PPC_BOOK3S_64
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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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.global kvmppc_handler_highmem
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kvmppc_handler_highmem:
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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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/* R7 = vcpu */
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PPC_LL r7, GPR4(r1)
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#ifdef CONFIG_PPC_BOOK3S_64
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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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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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mr r5, r12
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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)
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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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