From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH v2 9/9] qemu-kvm: hpet: Add MSI support for in-kernel irqchip mode Date: Tue, 26 Apr 2011 15:58:42 +0200 Message-ID: <4DB6CF92.2010905@siemens.com> References: <3d089633897515a214af032ed633342a7001945f.1303823975.git.jan.kiszka@siemens.com> <4DB6C90F.4090401@msgid.tls.msk.ru> <4DB6CEDB.8000200@siemens.com> <4DB6CF29.1030100@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Michael Tokarev , Marcelo Tosatti , "kvm@vger.kernel.org" , "Michael S. Tsirkin" To: Avi Kivity Return-path: Received: from goliath.siemens.de ([192.35.17.28]:29828 "EHLO goliath.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754361Ab1DZN67 (ORCPT ); Tue, 26 Apr 2011 09:58:59 -0400 In-Reply-To: <4DB6CF29.1030100@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 2011-04-26 15:56, Avi Kivity wrote: > On 04/26/2011 04:55 PM, Jan Kiszka wrote: >> On 2011-04-26 15:30, Michael Tokarev wrote: >>> 26.04.2011 17:19, Jan Kiszka wrote: >>> >>>> hw/hpet.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++- >>> >>>> +static int modifying_bit(uint64_t old, uint64_t new, uint64_t mask) >>>> +{ >>>> + return (old ^ new)& mask; >>>> +} >>> >>> Such constructs always look suspicious. I'm not even sure anymore >>> (after using C for over 20 years ;) that this works... how about >>> >>> return (old ^ new)& mask ? 1 : 0; >>> >>> instead, or something along this? I mean, if sizeof(int)==4, how >>> `return 1ULL<<32' will be interpreted in this context? Tiny test >>> program tells me it will return 0... >> >> Good catch, will fix (doesn't bite use here, flags fit into 32 bit, but >> nevertheless). >> > > Note, a bool return type works here. Yes, that was my favorite as well. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux