From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 56B671A0008 for ; Wed, 25 Jun 2014 07:46:27 +1000 (EST) Message-ID: <1403646374.4587.178.camel@pasglop> Subject: Re: [PATCH] vfio: Fix endianness handling for emulated BARs From: Benjamin Herrenschmidt To: Alexander Graf Date: Wed, 25 Jun 2014 07:46:14 +1000 In-Reply-To: <53A955F5.6050801@suse.de> References: <1403091391-31780-1-git-send-email-aik@ozlabs.ru> <1403116512.3707.175.camel@ul30vt.home> <53A233E9.6030006@ozlabs.ru> <53A241F6.9010307@ozlabs.ru> <53A25D74.5000804@ozlabs.ru> <1403234514.3707.278.camel@ul30vt.home> <1403305961.4587.66.camel@pasglop> <53A94EBD.101@ozlabs.ru> <53A955F5.6050801@suse.de> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Cc: kvm@vger.kernel.org, Nikunj A Dadhania , Alexey Kardashevskiy , linux-kernel@vger.kernel.org, Alex Williamson , linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2014-06-24 at 12:41 +0200, Alexander Graf wrote: > Is there actually any difference in generated code with this patch > applied and without? I would hope that iowrite..() is inlined and > cancels out the cpu_to_le..() calls that are also inlined? No, the former uses byteswapping asm, the compiler can't "cancel" it out, but the overhead of the additional byteswap might not be measurable. Cheers, Ben.