From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5095C31E46 for ; Wed, 12 Jun 2019 06:53:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6AF74205ED for ; Wed, 12 Jun 2019 06:53:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="GFvtK0jF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2407664AbfFLGxR (ORCPT ); Wed, 12 Jun 2019 02:53:17 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:45542 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2407244AbfFLGxQ (ORCPT ); Wed, 12 Jun 2019 02:53:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=xgUX4NVL92gkxOqiTvw1J9XqeyQ+MJXpugSZPm13AZs=; b=GFvtK0jFohgoH84MW52pkyI40 R1zEfRmP4a24R6XxrcvPT3RRZbLFUlUtEPxsULpUAaAK5nCVL8Sz4cA+wGpXZQLudidQvzYR6dqkg 89yQXiFkJzeTJdX/YYYJ56lXLo7Vk7rvNbee/3ocS7fbGmRvhLPyyxwLW15FdZIKkNpcEiWvDopqf T5QXYgcpiInC9kdOYDQXsM2QV5ii8Ur0ZT715wd7lQ4es8wB89/njfaF11nBFSWsohi1P3z+9BFJ3 OAbEfmPM0p4yE9eul8AJt2Eav6KrJtgquUD1xJPHnz2v0ox9BgG1BUWkq/2M7rQLshhgGHGEbLL31 JxdnZzHKg==; Received: from hch by bombadil.infradead.org with local (Exim 4.92 #3 (Red Hat Linux)) id 1hax8E-0000qt-4p; Wed, 12 Jun 2019 06:53:14 +0000 Date: Tue, 11 Jun 2019 23:53:14 -0700 From: Christoph Hellwig To: Oliver O'Halloran Cc: Oded Gabbay , Greg KH , linuxppc-dev@ozlabs.org, Christoph Hellwig , "Linux-Kernel@Vger. Kernel. Org" Subject: Re: [PATCH v2 8/8] habanalabs: enable 64-bit DMA mask in POWER9 Message-ID: <20190612065314.GA28838@infradead.org> References: <20190611092144.11194-1-oded.gabbay@gmail.com> <20190611095857.GB24058@kroah.com> <20190611151753.GA11404@infradead.org> <20190611152655.GA3972@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.4 (2019-03-13) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 12, 2019 at 04:35:22PM +1000, Oliver O'Halloran wrote: > Setting a 48 bit DMA mask doesn't work today because we only allocate > IOMMU tables to cover the 0..2GB range of PCI bus addresses. I don't think that is true upstream, and if it is we need to fix bug in the powerpc code. powerpc should be falling back treating a 48-bit dma mask like a 32-bit one at least, that is use dynamic iommu mappings instead of using the direct mapping. And from my reding of arch/powerpc/kernel/dma-iommu.c that is exactly what it does.