[PATCH 15/30] KVM: arm64: Refactor enter_exception64()
From: Will Deacon <will@kernel.org>
Date: 2026-01-05 15:50:49
Also in:
kvmarm
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
From: Quentin Perret <redacted> In order to simplify the injection of exceptions in the host in pkvm context, refactor enter_exception64() to separate the code calculating the exception offset from VBAR_EL1 and the cpsr. No functional change intended. Signed-off-by: Quentin Perret <redacted> Signed-off-by: Will Deacon <will@kernel.org> --- arch/arm64/include/asm/kvm_emulate.h | 5 ++ arch/arm64/kvm/hyp/exception.c | 100 ++++++++++++++++----------- 2 files changed, 63 insertions(+), 42 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index c9eab316398e..c3f04bd5b2a5 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h@@ -71,6 +71,11 @@ static inline int kvm_inject_serror(struct kvm_vcpu *vcpu) return kvm_inject_serror_esr(vcpu, ESR_ELx_ISV); } +unsigned long get_except64_offset(unsigned long psr, unsigned long target_mode, + enum exception_type type); +unsigned long get_except64_cpsr(unsigned long old, bool has_mte, + unsigned long sctlr, unsigned long mode); + void kvm_vcpu_wfi(struct kvm_vcpu *vcpu); void kvm_emulate_nested_eret(struct kvm_vcpu *vcpu);
diff --git a/arch/arm64/kvm/hyp/exception.c b/arch/arm64/kvm/hyp/exception.c
index bef40ddb16db..d3bcda665612 100644
--- a/arch/arm64/kvm/hyp/exception.c
+++ b/arch/arm64/kvm/hyp/exception.c@@ -65,12 +65,25 @@ static void __vcpu_write_spsr_und(struct kvm_vcpu *vcpu, u64 val) vcpu->arch.ctxt.spsr_und = val; } +unsigned long get_except64_offset(unsigned long psr, unsigned long target_mode, + enum exception_type type) +{ + u64 mode = psr & (PSR_MODE_MASK | PSR_MODE32_BIT); + u64 exc_offset; + + if (mode == target_mode) + exc_offset = CURRENT_EL_SP_ELx_VECTOR; + else if ((mode | PSR_MODE_THREAD_BIT) == target_mode) + exc_offset = CURRENT_EL_SP_EL0_VECTOR; + else if (!(mode & PSR_MODE32_BIT)) + exc_offset = LOWER_EL_AArch64_VECTOR; + else + exc_offset = LOWER_EL_AArch32_VECTOR; + + return exc_offset + type; +} + /* - * This performs the exception entry at a given EL (@target_mode), stashing PC - * and PSTATE into ELR and SPSR respectively, and compute the new PC/PSTATE. - * The EL passed to this function *must* be a non-secure, privileged mode with - * bit 0 being set (PSTATE.SP == 1). - * * When an exception is taken, most PSTATE fields are left unchanged in the * handler. However, some are explicitly overridden (e.g. M[4:0]). Luckily all * of the inherited bits have the same position in the AArch64/AArch32 SPSR_ELx
@@ -82,50 +95,17 @@ static void __vcpu_write_spsr_und(struct kvm_vcpu *vcpu, u64 val) * Here we manipulate the fields in order of the AArch64 SPSR_ELx layout, from * MSB to LSB. */ -static void enter_exception64(struct kvm_vcpu *vcpu, unsigned long target_mode, - enum exception_type type) +unsigned long get_except64_cpsr(unsigned long old, bool has_mte, + unsigned long sctlr, unsigned long target_mode) { - unsigned long sctlr, vbar, old, new, mode; - u64 exc_offset; - - mode = *vcpu_cpsr(vcpu) & (PSR_MODE_MASK | PSR_MODE32_BIT); - - if (mode == target_mode) - exc_offset = CURRENT_EL_SP_ELx_VECTOR; - else if ((mode | PSR_MODE_THREAD_BIT) == target_mode) - exc_offset = CURRENT_EL_SP_EL0_VECTOR; - else if (!(mode & PSR_MODE32_BIT)) - exc_offset = LOWER_EL_AArch64_VECTOR; - else - exc_offset = LOWER_EL_AArch32_VECTOR; - - switch (target_mode) { - case PSR_MODE_EL1h: - vbar = __vcpu_read_sys_reg(vcpu, VBAR_EL1); - sctlr = __vcpu_read_sys_reg(vcpu, SCTLR_EL1); - __vcpu_write_sys_reg(vcpu, *vcpu_pc(vcpu), ELR_EL1); - break; - case PSR_MODE_EL2h: - vbar = __vcpu_read_sys_reg(vcpu, VBAR_EL2); - sctlr = __vcpu_read_sys_reg(vcpu, SCTLR_EL2); - __vcpu_write_sys_reg(vcpu, *vcpu_pc(vcpu), ELR_EL2); - break; - default: - /* Don't do that */ - BUG(); - } - - *vcpu_pc(vcpu) = vbar + exc_offset + type; - - old = *vcpu_cpsr(vcpu); - new = 0; + u64 new = 0; new |= (old & PSR_N_BIT); new |= (old & PSR_Z_BIT); new |= (old & PSR_C_BIT); new |= (old & PSR_V_BIT); - if (kvm_has_mte(kern_hyp_va(vcpu->kvm))) + if (has_mte) new |= PSR_TCO_BIT; new |= (old & PSR_DIT_BIT);
@@ -161,6 +141,42 @@ static void enter_exception64(struct kvm_vcpu *vcpu, unsigned long target_mode, new |= target_mode; + return new; +} + +/* + * This performs the exception entry at a given EL (@target_mode), stashing PC + * and PSTATE into ELR and SPSR respectively, and compute the new PC/PSTATE. + * The EL passed to this function *must* be a non-secure, privileged mode with + * bit 0 being set (PSTATE.SP == 1). + */ +static void enter_exception64(struct kvm_vcpu *vcpu, unsigned long target_mode, + enum exception_type type) +{ + u64 offset = get_except64_offset(*vcpu_cpsr(vcpu), target_mode, type); + unsigned long sctlr, vbar, old, new; + + switch (target_mode) { + case PSR_MODE_EL1h: + vbar = __vcpu_read_sys_reg(vcpu, VBAR_EL1); + sctlr = __vcpu_read_sys_reg(vcpu, SCTLR_EL1); + __vcpu_write_sys_reg(vcpu, *vcpu_pc(vcpu), ELR_EL1); + break; + case PSR_MODE_EL2h: + vbar = __vcpu_read_sys_reg(vcpu, VBAR_EL2); + sctlr = __vcpu_read_sys_reg(vcpu, SCTLR_EL2); + __vcpu_write_sys_reg(vcpu, *vcpu_pc(vcpu), ELR_EL2); + break; + default: + /* Don't do that */ + BUG(); + } + + *vcpu_pc(vcpu) = vbar + offset; + + old = *vcpu_cpsr(vcpu); + new = get_except64_cpsr(old, kvm_has_mte(kern_hyp_va(vcpu->kvm)), sctlr, + target_mode); *vcpu_cpsr(vcpu) = new; __vcpu_write_spsr(vcpu, target_mode, old); }
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2.52.0.351.gbe84eed79e-goog