From owner-freebsd-hackers@FreeBSD.ORG Mon Sep 26 19:29:51 2005 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 1B5A916A41F for ; Mon, 26 Sep 2005 19:29:51 +0000 (GMT) (envelope-from jhb@FreeBSD.org) Received: from mv.twc.weather.com (mv.twc.weather.com [65.212.71.225]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7A72943D5A for ; Mon, 26 Sep 2005 19:29:50 +0000 (GMT) (envelope-from jhb@FreeBSD.org) Received: from [10.50.41.233] (Not Verified[10.50.41.233]) by mv.twc.weather.com with NetIQ MailMarshal (v6, 0, 3, 8) id ; Mon, 26 Sep 2005 15:45:46 -0400 From: John Baldwin To: freebsd-hackers@freebsd.org, hselasky@c2i.net Date: Mon, 26 Sep 2005 15:25:05 -0400 User-Agent: KMail/1.8 References: <200509261931.46052.hselasky@c2i.net> In-Reply-To: <200509261931.46052.hselasky@c2i.net> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200509261525.06653.jhb@FreeBSD.org> Cc: Subject: Re: bus-dma question X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 26 Sep 2005 19:29:51 -0000 On Monday 26 September 2005 01:31 pm, Hans Petter Selasky wrote: > Hi, > > I see something suspicious on Amd64, when allocating small blocks of > DMA-able memory: > > bus_dmamap_load_callback: 0x0000000000caf200 > ^^^^ this is physical address > > QH(0xffffff0000caf200) at 0x00caf200: > ^^^^ this is kernel address > > Shouldn't kernel addresses always be different from physical addresses ? No. Especially not on archs like alpha, ia64, amd64, and sparc64 where part of KVA is direct-mapped to physical memory either in hardware (alpha's K0Seg) or via software (ia64, amd64, and sparc64). > When allocating larger blocks of memory I get, for example: > > bus_dmamap_load_callback: 0x000000003bc50000 > > which seems correct. > > --HPS > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org