From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian Johnson Subject: Re: PIO port width on various archs? Date: Mon, 26 Feb 2007 10:52:47 -0600 Message-ID: <45E3105F.4070303@charter.net> References: <45E14F9D.3050502@qumranet.com> <1172464067.12245.4.camel@diesel> <45E27A94.3020400@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Return-path: In-Reply-To: <45E27A94.3020400-atKUWr5tajBWk0Htik3J/w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Avi Kivity wrote: > Hollis Blanchard wrote: >> On Sun, 2007-02-25 at 10:58 +0200, Avi Kivity wrote: >> >>> I'm changing the kvm userspace interface to be more friendly to other >>> archs. One issue is the PIO port size. x86 uses 16 bits to hold the >>> port size (64K ports). Is that an issue for other archs? >>> >>> I guess I could change it to __u32, but it's better to know what various >>> architectures actually require. >>> >> PowerPC doesn't have any such concept; access to ISA PIO is done by >> having the bridge translate a particular range of MMIO accesses as PIO. >> I'm no expert, but I don't know of any mainstream processor other than >> x86 that supports PIO. >> > > I think ia64 does, but it's probably exactly the same as x86. IA64 uses a special memory range which is translated into I/O port accesses by the CPU hardware (as opposed to the I/O bridge.) Section 10.7 of volume 2 of the Itanium SDM has the details. Only 64k of I/O ports is supported. Brian J. Johnson ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV