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https://github.com/brain-hackers/linux-brain.git
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3d584a3c85
When fall-through warnings was enabled by default, commit d93512ef0f0e
("Makefile: Globally enable fall-through warning"), the following
warnings was starting to show up:
In file included from ../arch/arm64/include/asm/kvm_emulate.h:19,
from ../arch/arm64/kvm/regmap.c:13:
../arch/arm64/kvm/regmap.c: In function ‘vcpu_write_spsr32’:
../arch/arm64/include/asm/kvm_hyp.h:31:3: warning: this statement may fall
through [-Wimplicit-fallthrough=]
asm volatile(ALTERNATIVE(__msr_s(r##nvh, "%x0"), \
^~~
../arch/arm64/include/asm/kvm_hyp.h:46:31: note: in expansion of macro ‘write_sysreg_elx’
#define write_sysreg_el1(v,r) write_sysreg_elx(v, r, _EL1, _EL12)
^~~~~~~~~~~~~~~~
../arch/arm64/kvm/regmap.c:180:3: note: in expansion of macro ‘write_sysreg_el1’
write_sysreg_el1(v, SYS_SPSR);
^~~~~~~~~~~~~~~~
../arch/arm64/kvm/regmap.c:181:2: note: here
case KVM_SPSR_ABT:
^~~~
In file included from ../arch/arm64/include/asm/cputype.h:132,
from ../arch/arm64/include/asm/cache.h:8,
from ../include/linux/cache.h:6,
from ../include/linux/printk.h:9,
from ../include/linux/kernel.h:15,
from ../include/asm-generic/bug.h:18,
from ../arch/arm64/include/asm/bug.h:26,
from ../include/linux/bug.h:5,
from ../include/linux/mmdebug.h:5,
from ../include/linux/mm.h:9,
from ../arch/arm64/kvm/regmap.c:11:
../arch/arm64/include/asm/sysreg.h:837:2: warning: this statement may fall
through [-Wimplicit-fallthrough=]
asm volatile("msr " __stringify(r) ", %x0" \
^~~
../arch/arm64/kvm/regmap.c:182:3: note: in expansion of macro ‘write_sysreg’
write_sysreg(v, spsr_abt);
^~~~~~~~~~~~
../arch/arm64/kvm/regmap.c:183:2: note: here
case KVM_SPSR_UND:
^~~~
Rework to add a 'break;' in the swich-case since it didn't have that,
leading to an interresting set of bugs.
Cc: stable@vger.kernel.org # v4.17+
Fixes: a892819560 ("KVM: arm64: Prepare to handle deferred save/restore of 32-bit registers")
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
[maz: reworked commit message, fixed stable range]
Signed-off-by: Marc Zyngier <maz@kernel.org>
196 lines
5.0 KiB
C
196 lines
5.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2012,2013 - ARM Ltd
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* Author: Marc Zyngier <marc.zyngier@arm.com>
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*
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* Derived from arch/arm/kvm/emulate.c:
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* Copyright (C) 2012 - Virtual Open Systems and Columbia University
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* Author: Christoffer Dall <c.dall@virtualopensystems.com>
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*/
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#include <linux/mm.h>
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#include <linux/kvm_host.h>
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#include <asm/kvm_emulate.h>
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#include <asm/ptrace.h>
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#define VCPU_NR_MODES 6
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#define REG_OFFSET(_reg) \
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(offsetof(struct user_pt_regs, _reg) / sizeof(unsigned long))
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#define USR_REG_OFFSET(R) REG_OFFSET(compat_usr(R))
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static const unsigned long vcpu_reg_offsets[VCPU_NR_MODES][16] = {
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/* USR Registers */
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{
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USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
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USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
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USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
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USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
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USR_REG_OFFSET(12), USR_REG_OFFSET(13), USR_REG_OFFSET(14),
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REG_OFFSET(pc)
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},
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/* FIQ Registers */
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{
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USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
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USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
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USR_REG_OFFSET(6), USR_REG_OFFSET(7),
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REG_OFFSET(compat_r8_fiq), /* r8 */
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REG_OFFSET(compat_r9_fiq), /* r9 */
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REG_OFFSET(compat_r10_fiq), /* r10 */
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REG_OFFSET(compat_r11_fiq), /* r11 */
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REG_OFFSET(compat_r12_fiq), /* r12 */
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REG_OFFSET(compat_sp_fiq), /* r13 */
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REG_OFFSET(compat_lr_fiq), /* r14 */
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REG_OFFSET(pc)
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},
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/* IRQ Registers */
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{
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USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
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USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
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USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
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USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
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USR_REG_OFFSET(12),
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REG_OFFSET(compat_sp_irq), /* r13 */
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REG_OFFSET(compat_lr_irq), /* r14 */
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REG_OFFSET(pc)
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},
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/* SVC Registers */
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{
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USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
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USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
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USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
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USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
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USR_REG_OFFSET(12),
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REG_OFFSET(compat_sp_svc), /* r13 */
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REG_OFFSET(compat_lr_svc), /* r14 */
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REG_OFFSET(pc)
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},
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/* ABT Registers */
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{
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USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
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USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
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USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
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USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
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USR_REG_OFFSET(12),
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REG_OFFSET(compat_sp_abt), /* r13 */
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REG_OFFSET(compat_lr_abt), /* r14 */
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REG_OFFSET(pc)
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},
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/* UND Registers */
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{
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USR_REG_OFFSET(0), USR_REG_OFFSET(1), USR_REG_OFFSET(2),
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USR_REG_OFFSET(3), USR_REG_OFFSET(4), USR_REG_OFFSET(5),
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USR_REG_OFFSET(6), USR_REG_OFFSET(7), USR_REG_OFFSET(8),
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USR_REG_OFFSET(9), USR_REG_OFFSET(10), USR_REG_OFFSET(11),
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USR_REG_OFFSET(12),
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REG_OFFSET(compat_sp_und), /* r13 */
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REG_OFFSET(compat_lr_und), /* r14 */
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REG_OFFSET(pc)
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},
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};
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/*
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* Return a pointer to the register number valid in the current mode of
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* the virtual CPU.
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*/
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unsigned long *vcpu_reg32(const struct kvm_vcpu *vcpu, u8 reg_num)
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{
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unsigned long *reg_array = (unsigned long *)&vcpu->arch.ctxt.gp_regs.regs;
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unsigned long mode = *vcpu_cpsr(vcpu) & PSR_AA32_MODE_MASK;
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switch (mode) {
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case PSR_AA32_MODE_USR ... PSR_AA32_MODE_SVC:
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mode &= ~PSR_MODE32_BIT; /* 0 ... 3 */
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break;
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case PSR_AA32_MODE_ABT:
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mode = 4;
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break;
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case PSR_AA32_MODE_UND:
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mode = 5;
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break;
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case PSR_AA32_MODE_SYS:
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mode = 0; /* SYS maps to USR */
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break;
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default:
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BUG();
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}
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return reg_array + vcpu_reg_offsets[mode][reg_num];
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}
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/*
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* Return the SPSR for the current mode of the virtual CPU.
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*/
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static int vcpu_spsr32_mode(const struct kvm_vcpu *vcpu)
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{
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unsigned long mode = *vcpu_cpsr(vcpu) & PSR_AA32_MODE_MASK;
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switch (mode) {
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case PSR_AA32_MODE_SVC: return KVM_SPSR_SVC;
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case PSR_AA32_MODE_ABT: return KVM_SPSR_ABT;
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case PSR_AA32_MODE_UND: return KVM_SPSR_UND;
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case PSR_AA32_MODE_IRQ: return KVM_SPSR_IRQ;
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case PSR_AA32_MODE_FIQ: return KVM_SPSR_FIQ;
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default: BUG();
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}
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}
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unsigned long vcpu_read_spsr32(const struct kvm_vcpu *vcpu)
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{
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int spsr_idx = vcpu_spsr32_mode(vcpu);
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if (!vcpu->arch.sysregs_loaded_on_cpu)
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return vcpu_gp_regs(vcpu)->spsr[spsr_idx];
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switch (spsr_idx) {
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case KVM_SPSR_SVC:
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return read_sysreg_el1(SYS_SPSR);
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case KVM_SPSR_ABT:
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return read_sysreg(spsr_abt);
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case KVM_SPSR_UND:
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return read_sysreg(spsr_und);
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case KVM_SPSR_IRQ:
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return read_sysreg(spsr_irq);
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case KVM_SPSR_FIQ:
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return read_sysreg(spsr_fiq);
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default:
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BUG();
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}
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}
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void vcpu_write_spsr32(struct kvm_vcpu *vcpu, unsigned long v)
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{
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int spsr_idx = vcpu_spsr32_mode(vcpu);
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if (!vcpu->arch.sysregs_loaded_on_cpu) {
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vcpu_gp_regs(vcpu)->spsr[spsr_idx] = v;
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return;
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}
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switch (spsr_idx) {
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case KVM_SPSR_SVC:
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write_sysreg_el1(v, SYS_SPSR);
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break;
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case KVM_SPSR_ABT:
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write_sysreg(v, spsr_abt);
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break;
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case KVM_SPSR_UND:
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write_sysreg(v, spsr_und);
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break;
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case KVM_SPSR_IRQ:
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write_sysreg(v, spsr_irq);
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break;
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case KVM_SPSR_FIQ:
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write_sysreg(v, spsr_fiq);
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break;
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}
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}
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