[PATCH v1 06/11] KVM: arm64: Factor out reusable vCPU reset helpers
From: <hidden>
Date: 2026-06-12 06:59:34
Also in:
kvmarm, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
Pull the reusable pieces out of kvm_reset_vcpu(): expose the reset PSTATE values in kvm_arm.h, and split the core register reset and the PSCI-driven reset into kvm_reset_vcpu_core() and kvm_reset_vcpu_psci(). A follow-up series reuses these to reset protected vCPUs at EL2. No functional change intended. Signed-off-by: Fuad Tabba <redacted> --- arch/arm64/include/asm/kvm_arm.h | 12 ++++++ arch/arm64/include/asm/kvm_emulate.h | 58 +++++++++++++++++++++++++++ arch/arm64/kvm/reset.c | 60 ++-------------------------- 3 files changed, 73 insertions(+), 57 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index 3f9233b5a130..aba4ec09acd2 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h@@ -348,4 +348,16 @@ { PSR_AA32_MODE_UND, "32-bit UND" }, \ { PSR_AA32_MODE_SYS, "32-bit SYS" } +/* + * ARMv8 Reset Values + */ +#define VCPU_RESET_PSTATE_EL1 (PSR_MODE_EL1h | PSR_A_BIT | PSR_I_BIT | \ + PSR_F_BIT | PSR_D_BIT) + +#define VCPU_RESET_PSTATE_EL2 (PSR_MODE_EL2h | PSR_A_BIT | PSR_I_BIT | \ + PSR_F_BIT | PSR_D_BIT) + +#define VCPU_RESET_PSTATE_SVC (PSR_AA32_MODE_SVC | PSR_AA32_A_BIT | \ + PSR_AA32_I_BIT | PSR_AA32_F_BIT) + #endif /* __ARM64_KVM_ARM_H__ */
diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index aed9fc0b717b..8436e71c402d 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h@@ -704,4 +704,62 @@ static inline void vcpu_set_hcrx(struct kvm_vcpu *vcpu) vcpu->arch.hcrx_el2 |= HCRX_EL2_EnASR; } } + +/* Reset a vcpu's core registers. */ +static inline void kvm_reset_vcpu_core(struct kvm_vcpu *vcpu) +{ + u32 pstate; + + if (vcpu_el1_is_32bit(vcpu)) { + pstate = VCPU_RESET_PSTATE_SVC; + } else if (vcpu_has_nv(vcpu)) { + pstate = VCPU_RESET_PSTATE_EL2; + } else { + pstate = VCPU_RESET_PSTATE_EL1; + } + + /* Reset core registers */ + memset(vcpu_gp_regs(vcpu), 0, sizeof(*vcpu_gp_regs(vcpu))); + memset(&vcpu->arch.ctxt.fp_regs, 0, sizeof(vcpu->arch.ctxt.fp_regs)); + vcpu->arch.ctxt.spsr_abt = 0; + vcpu->arch.ctxt.spsr_und = 0; + vcpu->arch.ctxt.spsr_irq = 0; + vcpu->arch.ctxt.spsr_fiq = 0; + vcpu_gp_regs(vcpu)->pstate = pstate; +} + +/* PSCI reset handling for a vcpu. */ +static inline void kvm_reset_vcpu_psci(struct kvm_vcpu *vcpu, + struct vcpu_reset_state *reset_state) +{ + unsigned long target_pc = reset_state->pc; + + /* Gracefully handle Thumb2 entry point */ + if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) { + target_pc &= ~1UL; + vcpu_set_thumb(vcpu); + } + + /* Propagate caller endianness */ + if (reset_state->be) + kvm_vcpu_set_be(vcpu); + + *vcpu_pc(vcpu) = target_pc; + + /* + * We may come from a state where either a PC update was + * pending (SMC call resulting in PC being increpented to + * skip the SMC) or a pending exception. Make sure we get + * rid of all that, as this cannot be valid out of reset. + * + * Note that clearing the exception mask also clears PC + * updates, but that's an implementation detail, and we + * really want to make it explicit. + */ + vcpu_clear_flag(vcpu, PENDING_EXCEPTION); + vcpu_clear_flag(vcpu, EXCEPT_MASK); + vcpu_clear_flag(vcpu, INCREMENT_PC); + vcpu_set_reg(vcpu, 0, reset_state->r0); +} + #endif /* __ARM64_KVM_EMULATE_H__ */
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 60969d90bdd3..e22d0be9e57c 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c@@ -34,18 +34,6 @@ static u32 __ro_after_init kvm_ipa_limit; unsigned int __ro_after_init kvm_host_sve_max_vl; -/* - * ARMv8 Reset Values - */ -#define VCPU_RESET_PSTATE_EL1 (PSR_MODE_EL1h | PSR_A_BIT | PSR_I_BIT | \ - PSR_F_BIT | PSR_D_BIT) - -#define VCPU_RESET_PSTATE_EL2 (PSR_MODE_EL2h | PSR_A_BIT | PSR_I_BIT | \ - PSR_F_BIT | PSR_D_BIT) - -#define VCPU_RESET_PSTATE_SVC (PSR_AA32_MODE_SVC | PSR_AA32_A_BIT | \ - PSR_AA32_I_BIT | PSR_AA32_F_BIT) - unsigned int __ro_after_init kvm_sve_max_vl; int __init kvm_arm_init_sve(void)
@@ -191,7 +179,6 @@ void kvm_reset_vcpu(struct kvm_vcpu *vcpu) { struct vcpu_reset_state reset_state; bool loaded; - u32 pstate; scoped_guard(spinlock, &vcpu->arch.mp_state_lock) { reset_state = vcpu->arch.reset_state;
@@ -210,21 +197,8 @@ void kvm_reset_vcpu(struct kvm_vcpu *vcpu) kvm_vcpu_reset_sve(vcpu); } - if (vcpu_el1_is_32bit(vcpu)) - pstate = VCPU_RESET_PSTATE_SVC; - else if (vcpu_has_nv(vcpu)) - pstate = VCPU_RESET_PSTATE_EL2; - else - pstate = VCPU_RESET_PSTATE_EL1; - /* Reset core registers */ - memset(vcpu_gp_regs(vcpu), 0, sizeof(*vcpu_gp_regs(vcpu))); - memset(&vcpu->arch.ctxt.fp_regs, 0, sizeof(vcpu->arch.ctxt.fp_regs)); - vcpu->arch.ctxt.spsr_abt = 0; - vcpu->arch.ctxt.spsr_und = 0; - vcpu->arch.ctxt.spsr_irq = 0; - vcpu->arch.ctxt.spsr_fiq = 0; - vcpu_gp_regs(vcpu)->pstate = pstate; + kvm_reset_vcpu_core(vcpu); /* Reset system registers */ kvm_reset_sys_regs(vcpu);
@@ -233,36 +207,8 @@ void kvm_reset_vcpu(struct kvm_vcpu *vcpu) * Additional reset state handling that PSCI may have imposed on us. * Must be done after all the sys_reg reset. */ - if (reset_state.reset) { - unsigned long target_pc = reset_state.pc; - - /* Gracefully handle Thumb2 entry point */ - if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) { - target_pc &= ~1UL; - vcpu_set_thumb(vcpu); - } - - /* Propagate caller endianness */ - if (reset_state.be) - kvm_vcpu_set_be(vcpu); - - *vcpu_pc(vcpu) = target_pc; - - /* - * We may come from a state where either a PC update was - * pending (SMC call resulting in PC being increpented to - * skip the SMC) or a pending exception. Make sure we get - * rid of all that, as this cannot be valid out of reset. - * - * Note that clearing the exception mask also clears PC - * updates, but that's an implementation detail, and we - * really want to make it explicit. - */ - vcpu_clear_flag(vcpu, PENDING_EXCEPTION); - vcpu_clear_flag(vcpu, EXCEPT_MASK); - vcpu_clear_flag(vcpu, INCREMENT_PC); - vcpu_set_reg(vcpu, 0, reset_state.r0); - } + if (reset_state.reset) + kvm_reset_vcpu_psci(vcpu, &reset_state); /* Reset timer */ kvm_timer_vcpu_reset(vcpu);
--
2.54.0.1136.gdb2ca164c4-goog