On Wed, Aug 29, 2018 at 12:05:06PM +0300, Liran Alon wrote: > > arch/x86/kvm/lapic.c | 17 +++++++++++++---- > > 1 file changed, 13 insertions(+), 4 deletions(-) > > > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > > index 0cefba2..86e933c 100644 > > --- a/arch/x86/kvm/lapic.c > > +++ b/arch/x86/kvm/lapic.c > > @@ -571,18 +571,27 @@ int kvm_pv_send_ipi(struct kvm *kvm, unsigned long ipi_bitmap_low, > > rcu_read_lock(); > > map = rcu_dereference(kvm->arch.apic_map); > > > > + if (unlikely((s32)(map->max_apic_id - __fls(ipi_bitmap_low)) < min)) > > + goto out; > > I personally think “if ((min + __fls(ipi_bitmap_low)) > map->max_apic_id)” is more readable. > But that’s just a matter of taste :) That's an integer overflow. But I do prefer to put the variable on the left. The truth is that some Smatch checks just ignore code which is backwards written because otherwise you have to write duplicate code and the most code is written with the variable on the left. if (min > (s32)(map->max_apic_id - __fls(ipi_bitmap_low)) Shouldn't this be >= instead? It looks off by one. regards, dan carpenter
