Sean Christopherson <sean.j.christopherson@xxxxxxxxx> writes: > On Fri, Mar 15, 2019 at 10:14:47AM +0100, Vitaly Kuznetsov wrote: >> "Li,Rongqing" <lirongqing@xxxxxxxxx> writes: >> >> >> -----邮件原件----- >> >> 发件人: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx] >> >> 发送时间: 2019年3月14日 21:23 >> >> 收件人: Li,Rongqing <lirongqing@xxxxxxxxx> >> >> 抄送: x86@xxxxxxxxxx; kvm@xxxxxxxxxxxxxxx >> >> 主题: Re: [PATCH] KVM: svm: merge incomplete IPI emulation handling >> >> >> >> Li RongQing <lirongqing@xxxxxxxxx> writes: >> >> >> >> > Invalid int type emulation and target not running emulation have same >> >> > codes, which update APIC ICR high/low registers, and emulate sending >> >> > the IPI. >> >> > >> >> > so fall through this switch cases to reduce duplicate codes >> >> > >> >> > Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx> >> >> > Signed-off-by: Zhang Yu <zhangyu31@xxxxxxxxx> >> >> > --- >> >> > arch/x86/kvm/svm.c | 5 ----- >> >> > 1 file changed, 5 deletions(-) >> >> > >> >> > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index >> >> > 276ab8ab6c95..2e0c9cb349d2 100644 >> >> > --- a/arch/x86/kvm/svm.c >> >> > +++ b/arch/x86/kvm/svm.c >> >> > @@ -4508,12 +4508,7 @@ static int avic_incomplete_ipi_interception(struct >> >> vcpu_svm *svm) >> >> > * formats are supported. All other IPI types cause >> >> > * a #VMEXIT, which needs to emulated. >> >> > */ >> >> > - kvm_lapic_reg_write(apic, APIC_ICR2, icrh); >> >> > - kvm_lapic_reg_write(apic, APIC_ICR, icrl); >> >> > - break; >> >> >> >> >> >> Doesn't checkpatch.pl complain about missing 'Fall through' comment here? In >> >> any case it's probably worth it adding it. >> >> >> > >> > This place is a empty case block, which does not need the mark "fall through" >> > So checkpatch.pl did not complain, and gcc did not complain >> > >> > And I have sent patch to remove this unnecessary "fall through" before >> > >> >> (I'm not insisting on the change) >> >> Generally it makes sense to explicitly say 'fall through' in each 'case' >> without a 'break' to assist readers of the code, it's very easy to miss >> this subtle thing otherwise (just IMO). > > How about redoing the comments so that the cases statements are back-to-back? > I think that would resolve Vitaly's concern but also avoid the unnecessary > "fall through" annotation. It also provides an opportunity to trim a few > lines by widing the comment out to 80 columns. Sounds awesome to me! Back-to-back case statements obviously don't require "fall through" comments. -- Vitaly
