From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: [PATCH] ARM(64): KVM: add signed type cast for comparation Date: Mon, 29 Jul 2013 20:45:31 -0700 Message-ID: <20130730034531.GC5471@cbox> References: <51ECA4EC.3000408@asianux.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Gleb Natapov , pbonzini@redhat.com, Russell King - ARM Linux , kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, "linux-arm-kernel@lists.infradead.org" , Catalin Marinas , Will Deacon To: Chen Gang Return-path: Received: from mail-pd0-f173.google.com ([209.85.192.173]:43746 "EHLO mail-pd0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754623Ab3G3Dps (ORCPT ); Mon, 29 Jul 2013 23:45:48 -0400 Received: by mail-pd0-f173.google.com with SMTP id p11so2056988pdj.18 for ; Mon, 29 Jul 2013 20:45:48 -0700 (PDT) Content-Disposition: inline In-Reply-To: <51ECA4EC.3000408@asianux.com> Sender: kvm-owner@vger.kernel.org List-ID: On Mon, Jul 22, 2013 at 11:20:12AM +0800, Chen Gang wrote: > 'len' is 'unsigned long' which is never less than zero. > > So need a related type cast for comparation. > > The related warning (when building ARM64 with allmodconfig): > > arch/arm64/kvm/../../../arch/arm/kvm/mmio.c:82:2: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits] > Hmmm, interesting, I don't get this error with my compiler. > > Signed-off-by: Chen Gang > --- > arch/arm/kvm/mmio.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c > index b8e06b7..626dfc8 100644 > --- a/arch/arm/kvm/mmio.c > +++ b/arch/arm/kvm/mmio.c > @@ -79,7 +79,7 @@ static int decode_hsr(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > } > > len = kvm_vcpu_dabt_get_as(vcpu); > - if (unlikely(len < 0)) > + if (unlikely((long)len < 0)) > return len; > > is_write = kvm_vcpu_dabt_iswrite(vcpu); > -- > 1.7.7.6 I think the proper fix is to declare len as an int instead. I'll queue that instead. Thanks, -Christoffer