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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 49DB5C433EF for ; Thu, 30 Sep 2021 05:44:06 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 86CAA617E4 for ; Thu, 30 Sep 2021 05:44:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 86CAA617E4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4HKhxv4F02z3bhf for ; Thu, 30 Sep 2021 15:44:03 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lst.de (client-ip=213.95.11.211; helo=verein.lst.de; envelope-from=hch@lst.de; receiver=) Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4HKhxM2Mgqz2ynj for ; Thu, 30 Sep 2021 15:43:33 +1000 (AEST) Received: by verein.lst.de (Postfix, from userid 2407) id C56D867373; Thu, 30 Sep 2021 07:43:28 +0200 (CEST) Date: Thu, 30 Sep 2021 07:43:28 +0200 From: Christoph Hellwig To: Alexey Kardashevskiy Subject: Re: [PATCH kernel] powerpc/iommu: Report the correct most efficient DMA mask for PCI devices Message-ID: <20210930054328.GA22181@lst.de> References: <20210930034454.95794-1-aik@ozlabs.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210930034454.95794-1-aik@ozlabs.ru> User-Agent: Mutt/1.5.17 (2007-11-01) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Carol L Soto , iommu@lists.linux-foundation.org, linuxppc-dev@lists.ozlabs.org, Christoph Hellwig Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, Sep 30, 2021 at 01:44:54PM +1000, Alexey Kardashevskiy wrote: > and returns the IOMMU table mask on the pseries platform which makes some > drivers (mpt3sas is one example) choose 32bit DMA even though bypass is > supported. The powernv platform sort of handles it by having a bigger > default window with a mask >=40 but it only works as drivers choose > 63/64bit if the required mask is >32 which is rather pointless. > > This reintroduces the bypass capability check to let drivers make > a better choice of the DMA mask. > > Fixes: f1565c24b596 ("powerpc: use the generic dma_ops_bypass mode") > Signed-off-by: Alexey Kardashevskiy Looks good: Reviewed-by: Christoph Hellwig