Re: [PATCH -next 021/491] KERNEL VIRTUAL MACHINE FOR X86 (KVM/x86): Use fallthrough;

From: Paolo Bonzini <pbonzini@redhat.com>
To: Joe Perches <joe@perches.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH -next 021/491] KERNEL VIRTUAL MACHINE FOR X86 (KVM/x86): Use fallthrough;
Date: Wed, 11 Mar 2020 10:43:33 +0100	[thread overview]
Message-ID: <205522b8-a0f2-9baf-7365-782be0668d74@redhat.com> (raw)
In-Reply-To: <e5314fc18acfe821da47ea52fa074b4c414f9266.1583896348.git.joe@perches.com>

On 11/03/20 05:51, Joe Perches wrote:
> Convert the various uses of fallthrough comments to fallthrough;
> 
> Done via script
> Link: https://lore.kernel.org/lkml/b56602fcf79f849e733e7b521bb0e17895d390fa.1582230379.git.joe.com/
> 
> Signed-off-by: Joe Perches <joe@perches.com>
> ---
>  arch/x86/kvm/emulate.c  |  2 +-
>  arch/x86/kvm/hyperv.c   |  2 +-
>  arch/x86/kvm/irq_comm.c |  2 +-
>  arch/x86/kvm/lapic.c    |  6 +++---
>  arch/x86/kvm/mmu/mmu.c  |  2 +-
>  arch/x86/kvm/svm.c      |  2 +-
>  arch/x86/kvm/vmx/vmx.c  | 15 +++++++--------
>  arch/x86/kvm/x86.c      | 12 ++++--------
>  8 files changed, 19 insertions(+), 24 deletions(-)
> 
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index bc00642..bae4d8 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -3025,7 +3025,7 @@ static void string_registers_quirk(struct x86_emulate_ctxt *ctxt)
>  	case 0xa4:	/* movsb */
>  	case 0xa5:	/* movsd/w */
>  		*reg_rmw(ctxt, VCPU_REGS_RSI) &= (u32)-1;
> -		/* fall through */
> +		fallthrough;
>  	case 0xaa:	/* stosb */
>  	case 0xab:	/* stosd/w */
>  		*reg_rmw(ctxt, VCPU_REGS_RDI) &= (u32)-1;
> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
> index a86fda7..934bfb4 100644
> --- a/arch/x86/kvm/hyperv.c
> +++ b/arch/x86/kvm/hyperv.c
> @@ -1652,7 +1652,7 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
>  		ret = kvm_hvcall_signal_event(vcpu, fast, ingpa);
>  		if (ret != HV_STATUS_INVALID_PORT_ID)
>  			break;
> -		/* fall through - maybe userspace knows this conn_id. */
> +		fallthrough;	/* maybe userspace knows this conn_id */
>  	case HVCALL_POST_MESSAGE:
>  		/* don't bother userspace if it has no way to handle it */
>  		if (unlikely(rep || !vcpu_to_synic(vcpu)->active)) {
> diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
> index c47d2a..4aa1c2e 100644
> --- a/arch/x86/kvm/irq_comm.c
> +++ b/arch/x86/kvm/irq_comm.c
> @@ -285,7 +285,7 @@ int kvm_set_routing_entry(struct kvm *kvm,
>  		switch (ue->u.irqchip.irqchip) {
>  		case KVM_IRQCHIP_PIC_SLAVE:
>  			e->irqchip.pin += PIC_NUM_PINS / 2;
> -			/* fall through */
> +			fallthrough;
>  		case KVM_IRQCHIP_PIC_MASTER:
>  			if (ue->u.irqchip.pin >= PIC_NUM_PINS / 2)
>  				return -EINVAL;
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index e3099c..64b7a9c 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -1023,7 +1023,7 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
>  	switch (delivery_mode) {
>  	case APIC_DM_LOWEST:
>  		vcpu->arch.apic_arb_prio++;
> -		/* fall through */
> +		fallthrough;
>  	case APIC_DM_FIXED:
>  		if (unlikely(trig_mode && !level))
>  			break;
> @@ -1311,7 +1311,7 @@ static u32 __apic_read(struct kvm_lapic *apic, unsigned int offset)
>  		break;
>  	case APIC_TASKPRI:
>  		report_tpr_access(apic, false);
> -		/* fall thru */
> +		fallthrough;
>  	default:
>  		val = kvm_lapic_get_reg(apic, offset);
>  		break;
> @@ -1952,7 +1952,7 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
>  
>  	case APIC_LVT0:
>  		apic_manage_nmi_watchdog(apic, val);
> -		/* fall through */
> +		fallthrough;
>  	case APIC_LVTTHMR:
>  	case APIC_LVTPC:
>  	case APIC_LVT1:
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 87e9ba..8593cd 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -4475,7 +4475,7 @@ __reset_rsvds_bits_mask(struct kvm_vcpu *vcpu,
>  			rsvd_bits(maxphyaddr, 51);
>  		rsvd_check->rsvd_bits_mask[1][4] =
>  			rsvd_check->rsvd_bits_mask[0][4];
> -		/* fall through */
> +		fallthrough;
>  	case PT64_ROOT_4LEVEL:
>  		rsvd_check->rsvd_bits_mask[0][3] = exb_bit_rsvd |
>  			nonleaf_bit8_rsvd | rsvd_bits(7, 7) |
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 910005..73fa903 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -4449,7 +4449,7 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
>  	case MSR_IA32_APICBASE:
>  		if (kvm_vcpu_apicv_active(vcpu))
>  			avic_update_vapic_bar(to_svm(vcpu), data);
> -		/* Fall through */
> +		fallthrough;
>  	default:
>  		return kvm_set_msr_common(vcpu, msr);
>  	}
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 69c5bd..1577cd 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -4538,12 +4538,12 @@ static bool rmode_exception(struct kvm_vcpu *vcpu, int vec)
>  			vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
>  		if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP)
>  			return false;
> -		/* fall through */
> +		fallthrough;
>  	case DB_VECTOR:
>  		if (vcpu->guest_debug &
>  			(KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))
>  			return false;
> -		/* fall through */
> +		fallthrough;
>  	case DE_VECTOR:
>  	case OF_VECTOR:
>  	case BR_VECTOR:
> @@ -4692,7 +4692,7 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu)
>  		}
>  		kvm_run->debug.arch.dr6 = dr6 | DR6_FIXED_1;
>  		kvm_run->debug.arch.dr7 = vmcs_readl(GUEST_DR7);
> -		/* fall through */
> +		fallthrough;
>  	case BP_VECTOR:
>  		/*
>  		 * Update instruction length as we may reinject #BP from
> @@ -5119,7 +5119,7 @@ static int handle_task_switch(struct kvm_vcpu *vcpu)
>  				error_code =
>  					vmcs_read32(IDT_VECTORING_ERROR_CODE);
>  			}
> -			/* fall through */
> +			fallthrough;
>  		case INTR_TYPE_SOFT_EXCEPTION:
>  			kvm_clear_exception_queue(vcpu);
>  			break;
> @@ -5469,8 +5469,7 @@ static int handle_invpcid(struct kvm_vcpu *vcpu)
>  		 * global flush. If needed, we could optimize this later by
>  		 * keeping track of global entries in shadow page tables.
>  		 */
> -
> -		/* fall-through */
> +		fallthrough;
>  	case INVPCID_TYPE_ALL_INCL_GLOBAL:
>  		kvm_mmu_unload(vcpu);
>  		return kvm_skip_emulated_instruction(vcpu);
> @@ -6401,7 +6400,7 @@ static void __vmx_complete_interrupts(struct kvm_vcpu *vcpu,
>  		break;
>  	case INTR_TYPE_SOFT_EXCEPTION:
>  		vcpu->arch.event_exit_inst_len = vmcs_read32(instr_len_field);
> -		/* fall through */
> +		fallthrough;
>  	case INTR_TYPE_HARD_EXCEPTION:
>  		if (idt_vectoring_info & VECTORING_INFO_DELIVER_CODE_MASK) {
>  			u32 err = vmcs_read32(error_code_field);
> @@ -6411,7 +6410,7 @@ static void __vmx_complete_interrupts(struct kvm_vcpu *vcpu,
>  		break;
>  	case INTR_TYPE_SOFT_INTR:
>  		vcpu->arch.event_exit_inst_len = vmcs_read32(instr_len_field);
> -		/* fall through */
> +		fallthrough;
>  	case INTR_TYPE_EXT_INTR:
>  		kvm_queue_interrupt(vcpu, vector, type == INTR_TYPE_SOFT_INTR);
>  		break;
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 2bbc0e0..e6280e 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1071,7 +1071,6 @@ static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
>  			vcpu->arch.eff_db[dr] = val;
>  		break;
>  	case 4:
> -		/* fall through */
>  	case 6:
>  		if (val & 0xffffffff00000000ULL)
>  			return -1; /* #GP */
> @@ -1079,7 +1078,6 @@ static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
>  		kvm_update_dr6(vcpu);
>  		break;
>  	case 5:
> -		/* fall through */
>  	default: /* 7 */
>  		if (!kvm_dr7_valid(val))
>  			return -1; /* #GP */
> @@ -1110,7 +1108,6 @@ int kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val)
>  		*val = vcpu->arch.db[array_index_nospec(dr, size)];
>  		break;
>  	case 4:
> -		/* fall through */
>  	case 6:
>  		if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
>  			*val = vcpu->arch.dr6;
> @@ -1118,7 +1115,6 @@ int kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val)
>  			*val = kvm_x86_ops->get_dr6(vcpu);
>  		break;
>  	case 5:
> -		/* fall through */
>  	default: /* 7 */
>  		*val = vcpu->arch.dr7;
>  		break;
> @@ -2885,7 +2881,8 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>  
>  	case MSR_K7_PERFCTR0 ... MSR_K7_PERFCTR3:
>  	case MSR_P6_PERFCTR0 ... MSR_P6_PERFCTR1:
> -		pr = true; /* fall through */
> +		pr = true;
> +		fallthrough;
>  	case MSR_K7_EVNTSEL0 ... MSR_K7_EVNTSEL3:
>  	case MSR_P6_EVNTSEL0 ... MSR_P6_EVNTSEL1:
>  		if (kvm_pmu_is_valid_msr(vcpu, msr))
> @@ -4181,8 +4178,7 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
>  	case KVM_CAP_HYPERV_SYNIC2:
>  		if (cap->args[0])
>  			return -EINVAL;
> -		/* fall through */
> -
> +		fallthrough;
>  	case KVM_CAP_HYPERV_SYNIC:
>  		if (!irqchip_in_kernel(vcpu->kvm))
>  			return -EINVAL;
> @@ -8478,7 +8474,7 @@ static inline int vcpu_block(struct kvm *kvm, struct kvm_vcpu *vcpu)
>  		vcpu->arch.pv.pv_unhalted = false;
>  		vcpu->arch.mp_state =
>  			KVM_MP_STATE_RUNNABLE;
> -		/* fall through */
> +		fallthrough;
>  	case KVM_MP_STATE_RUNNABLE:
>  		vcpu->arch.apf.halted = false;
>  		break;
> 

Acked-by: Paolo Bonzini <pbonzini@redhat.com>