From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:53846) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ROuF5-0006uy-9R for qemu-devel@nongnu.org; Fri, 11 Nov 2011 11:46:19 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ROuF4-0000cn-4x for qemu-devel@nongnu.org; Fri, 11 Nov 2011 11:46:15 -0500 Received: from cantor2.suse.de ([195.135.220.15]:41759 helo=mx2.suse.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ROuF3-0000cd-TQ for qemu-devel@nongnu.org; Fri, 11 Nov 2011 11:46:14 -0500 Message-ID: <4EBD5168.5060308@suse.de> Date: Fri, 11 Nov 2011 17:46:32 +0100 From: Alexander Graf MIME-Version: 1.0 References: <1320887981-2099-1-git-send-email-agraf@suse.de> <4A2D3614-438C-40F4-B3D1-A8ABF30FB82F@suse.de> <4EBD467F.7040107@suse.de> <4EBD4C57.1080709@suse.de> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] s390x: initialize virtio dev region List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: qemu-devel@nongnu.org On 11/11/2011 05:44 PM, Peter Maydell wrote: > On 11 November 2011 16:24, Alexander Graf wrote: >> On 11/11/2011 05:11 PM, Peter Maydell wrote: >>> Yes, so that's option (2) and you need to be using a target_phys_addr_t. >> But ram_size is ram_addr_t and is the ram size that I have available to use, >> so it's exactly the address that I want. I don't see your point. Should go >> jump through random useless hoops of doing >> >> target_phys_addr_t ram_end = ram_size; >> >> just because there are some subtile semantic differences between the two >> variables? They're integers at the end of the day. Both of them. > Because handing a ram_addr_t to something that wants a target_phys_addr_t > is a red flag that something might be wrong. (As is handing a variable > called _size to something that wants an address.) > > Force in Newtons and Force in pound-feet are also both just integers > at the end of the day, but that doesn't make them interchangeable: > http://en.wikipedia.org/wiki/Mars_Climate_Orbiter#Communications_loss Haha :). In this case, I pass ram_size indirectly to ram_alloc just a few lines above though, mapping it to 0. So while if this was normal device code I would agree with your reservation, in this case I don't think adding indirection buys us anything. Alex