From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Gibson Subject: Re: [PATCH 2 of 3] [KVM] Add DCR access information to struct kvm_run Date: Tue, 8 Apr 2008 13:54:41 +1000 Message-ID: <20080408035441.GA18501@localhost.localdomain> References: <474b35009da7b7bdb58c.1207601613@localhost.localdomain> <20080408011128.GA13454@localhost.localdomain> <200804072225.33040.hollisb@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net, linuxppc-dev@ozlabs.org, kvm-ppc-devel@lists.sourceforge.net To: Hollis Blanchard Return-path: Content-Disposition: inline In-Reply-To: <200804072225.33040.hollisb@us.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org On Mon, Apr 07, 2008 at 10:25:32PM -0500, Hollis Blanchard wrote: > On Monday 07 April 2008 20:11:28 David Gibson wrote: > > On Mon, Apr 07, 2008 at 03:53:33PM -0500, Hollis Blanchard wrote: > > > 1 file changed, 7 insertions(+) > > > include/linux/kvm.h | 7 +++++++ > > > > > > > > > Device Control Registers are essentially another address space found on > > > PowerPC 4xx processors, analogous to PIO on x86. DCRs are always 32 bits, > > > and are identified by a 32-bit number. > > > > Well... 10-bit, actually. > > The mtdcrux description in the ppc440x6 user manual says the following: > > Let the contents of register RA denote a Device Control Register. > The contents of GPR[RS] are placed into the designated Device Control > Register. > > I take that to mean that we must worry about 32 bits worth of DCR numbers. > Perhaps I should say "no more than" rather than "always". I think that's less misleading. mtdcrux is very new, anything which only has the mtdcr instruction certainly can't take DCR numbers above 10 bits, and I would expect that even on chips with mtdcrux the DCR bus is probably still only 10-bits, although it could be extended. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Register now and save $200. Hurry, offer ends at 11:59 p.m., Monday, April 7! Use priority code J8TLD2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone