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=-11.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 726B0C433DF for ; Mon, 13 Jul 2020 07:35:23 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 8C6CD20663 for ; Mon, 13 Jul 2020 07:35:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ozlabs-ru.20150623.gappssmtp.com header.i=@ozlabs-ru.20150623.gappssmtp.com header.b="Wrq2I/MW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8C6CD20663 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ozlabs.ru Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4B4wRD3fz1zDqV9 for ; Mon, 13 Jul 2020 17:35:20 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.ru (client-ip=2607:f8b0:4864:20::544; helo=mail-pg1-x544.google.com; envelope-from=aik@ozlabs.ru; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ozlabs.ru Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ozlabs-ru.20150623.gappssmtp.com header.i=@ozlabs-ru.20150623.gappssmtp.com header.a=rsa-sha256 header.s=20150623 header.b=Wrq2I/MW; dkim-atps=neutral Received: from mail-pg1-x544.google.com (mail-pg1-x544.google.com [IPv6:2607:f8b0:4864:20::544]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4B4wP76VYGzDqL5 for ; Mon, 13 Jul 2020 17:33:28 +1000 (AEST) Received: by mail-pg1-x544.google.com with SMTP id j19so5647041pgm.11 for ; Mon, 13 Jul 2020 00:33:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ozlabs-ru.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:autocrypt:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=7wXOsH2H7SE11ftN1oECGPb6WzsU/0FTfmI/DQyobkI=; b=Wrq2I/MWsjODAoCJNp73czwqr2cEo4pEX4ewuglN/rdDwp240S9sXpAV5Z4WxfMJxt hE9zvbqvDtbbVugxm3eQ71gV1mmK0RmVOn+ZBfaUMb8mcgFxdGDSQqI/6KM5Tc1ThV5B I4tD4jx89bSkYju/oXrMeTza3shF5YLc9Dtgkg6QOmBlb37SsEdQ7WO37u7hhuxpvsUS dvFx6zF0bV1WqCmvE8ZASeUqPZQEa6m3Ky7t9PtsvRptphA8CAV9SSD+reg/s5FdXdAL QkaP5VguX4Gm8fYTpHAsflr5AnQf/ImpmWq+p9RZw5nr901rRACCIe+L2+/HUNTL9WYW H0/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=7wXOsH2H7SE11ftN1oECGPb6WzsU/0FTfmI/DQyobkI=; b=g5NfT3djlUFzBbFkB+/yrP0isFxpbWNL81nahmV3fn6TEwOk+/4/qCjgi/nePMs4AM j7VfXELx/6bGwWgqHzYrxDr6ZwXvt7PCFfCccsgyWXb3766E3hQA5ruFAi9spoUwnQHY lWGfMhnOnGhT+/oDtfqrxDM/4bw1FpdrZbbULvcx1eZGaxq8eubsPoAUYAxtCL0lI3cg DFWEvAi6bmKr9iCZFB//V6Mz9UCf4vxLqgueztS8qD00mizrWL+paXUhvScQtzcdtqif SnZWM8UARmR1Dp4cMtgGFA8hYnXaBc2/votIBwRnjzdpD/lH8cIene8cr6U6UpFN63xw ewZQ== X-Gm-Message-State: AOAM532qE86yiZKuftZa61bYSZgPmoALuZsRAuvEdpTgAKZp6cuyYfiC qd41+rg89pkLAjScuXefEu65bA== X-Google-Smtp-Source: ABdhPJynOyQPO9gscwWImDYb2sLEkmu9S7o6v691VIIbwcDvN1BySlMM0qldtmpI4Fh+p5ngs0OjbA== X-Received: by 2002:a63:7246:: with SMTP id c6mr68073102pgn.422.1594625606877; Mon, 13 Jul 2020 00:33:26 -0700 (PDT) Received: from [192.168.10.94] (124-171-83-152.dyn.iinet.net.au. [124.171.83.152]) by smtp.gmail.com with ESMTPSA id nh14sm12988306pjb.4.2020.07.13.00.33.23 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 13 Jul 2020 00:33:26 -0700 (PDT) Subject: Re: [PATCH v3 4/6] powerpc/pseries/iommu: Remove default DMA window before creating DDW To: Leonardo Bras , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Thiago Jung Bauermann , Ram Pai References: <20200703061844.111865-1-leobras.c@gmail.com> <20200703061844.111865-5-leobras.c@gmail.com> From: Alexey Kardashevskiy Autocrypt: addr=aik@ozlabs.ru; keydata= mQINBE+rT0sBEADFEI2UtPRsLLvnRf+tI9nA8T91+jDK3NLkqV+2DKHkTGPP5qzDZpRSH6mD EePO1JqpVuIow/wGud9xaPA5uvuVgRS1q7RU8otD+7VLDFzPRiRE4Jfr2CW89Ox6BF+q5ZPV /pS4v4G9eOrw1v09lEKHB9WtiBVhhxKK1LnUjPEH3ifkOkgW7jFfoYgTdtB3XaXVgYnNPDFo PTBYsJy+wr89XfyHr2Ev7BB3Xaf7qICXdBF8MEVY8t/UFsesg4wFWOuzCfqxFmKEaPDZlTuR tfLAeVpslNfWCi5ybPlowLx6KJqOsI9R2a9o4qRXWGP7IwiMRAC3iiPyk9cknt8ee6EUIxI6 t847eFaVKI/6WcxhszI0R6Cj+N4y+1rHfkGWYWupCiHwj9DjILW9iEAncVgQmkNPpUsZECLT WQzMuVSxjuXW4nJ6f4OFHqL2dU//qR+BM/eJ0TT3OnfLcPqfucGxubhT7n/CXUxEy+mvWwnm s9p4uqVpTfEuzQ0/bE6t7dZdPBua7eYox1AQnk8JQDwC3Rn9kZq2O7u5KuJP5MfludMmQevm pHYEMF4vZuIpWcOrrSctJfIIEyhDoDmR34bCXAZfNJ4p4H6TPqPh671uMQV82CfTxTrMhGFq 8WYU2AH86FrVQfWoH09z1WqhlOm/KZhAV5FndwVjQJs1MRXD8QARAQABtCRBbGV4ZXkgS2Fy ZGFzaGV2c2tpeSA8YWlrQG96bGFicy5ydT6JAjgEEwECACIFAk+rT0sCGwMGCwkIBwMCBhUI AgkKCwQWAgMBAh4BAheAAAoJEIYTPdgrwSC5fAIP/0wf/oSYaCq9PhO0UP9zLSEz66SSZUf7 AM9O1rau1lJpT8RoNa0hXFXIVbqPPKPZgorQV8SVmYRLr0oSmPnTiZC82x2dJGOR8x4E01gK TanY53J/Z6+CpYykqcIpOlGsytUTBA+AFOpdaFxnJ9a8p2wA586fhCZHVpV7W6EtUPH1SFTQ q5xvBmr3KkWGjz1FSLH4FeB70zP6uyuf/B2KPmdlPkyuoafl2UrU8LBADi/efc53PZUAREih sm3ch4AxaL4QIWOmlE93S+9nHZSRo9jgGXB1LzAiMRII3/2Leg7O4hBHZ9Nki8/fbDo5///+ kD4L7UNbSUM/ACWHhd4m1zkzTbyRzvL8NAVQ3rckLOmju7Eu9whiPueGMi5sihy9VQKHmEOx OMEhxLRQbzj4ypRLS9a+oxk1BMMu9cd/TccNy0uwx2UUjDQw/cXw2rRWTRCxoKmUsQ+eNWEd iYLW6TCfl9CfHlT6A7Zmeqx2DCeFafqEd69DqR9A8W5rx6LQcl0iOlkNqJxxbbW3ddDsLU/Y r4cY20++WwOhSNghhtrroP+gouTOIrNE/tvG16jHs8nrYBZuc02nfX1/gd8eguNfVX/ZTHiR gHBWe40xBKwBEK2UeqSpeVTohYWGBkcd64naGtK9qHdo1zY1P55lHEc5Uhlk743PgAnOi27Q ns5zuQINBE+rT0sBEACnV6GBSm+25ACT+XAE0t6HHAwDy+UKfPNaQBNTTt31GIk5aXb2Kl/p AgwZhQFEjZwDbl9D/f2GtmUHWKcCmWsYd5M/6Ljnbp0Ti5/xi6FyfqnO+G/wD2VhGcKBId1X Em/B5y1kZVbzcGVjgD3HiRTqE63UPld45bgK2XVbi2+x8lFvzuFq56E3ZsJZ+WrXpArQXib2 hzNFwQleq/KLBDOqTT7H+NpjPFR09Qzfa7wIU6pMNF2uFg5ihb+KatxgRDHg70+BzQfa6PPA o1xioKXW1eHeRGMmULM0Eweuvpc7/STD3K7EJ5bBq8svoXKuRxoWRkAp9Ll65KTUXgfS+c0x gkzJAn8aTG0z/oEJCKPJ08CtYQ5j7AgWJBIqG+PpYrEkhjzSn+DZ5Yl8r+JnZ2cJlYsUHAB9 jwBnWmLCR3gfop65q84zLXRQKWkASRhBp4JK3IS2Zz7Nd/Sqsowwh8x+3/IUxVEIMaVoUaxk Wt8kx40h3VrnLTFRQwQChm/TBtXqVFIuv7/Mhvvcq11xnzKjm2FCnTvCh6T2wJw3de6kYjCO 7wsaQ2y3i1Gkad45S0hzag/AuhQJbieowKecuI7WSeV8AOFVHmgfhKti8t4Ff758Z0tw5Fpc BFDngh6Lty9yR/fKrbkkp6ux1gJ2QncwK1v5kFks82Cgj+DSXK6GUQARAQABiQIfBBgBAgAJ BQJPq09LAhsMAAoJEIYTPdgrwSC5NYEP/2DmcEa7K9A+BT2+G5GXaaiFa098DeDrnjmRvumJ BhA1UdZRdfqICBADmKHlJjj2xYo387sZpS6ABbhrFxM6s37g/pGPvFUFn49C47SqkoGcbeDz Ha7JHyYUC+Tz1dpB8EQDh5xHMXj7t59mRDgsZ2uVBKtXj2ZkbizSHlyoeCfs1gZKQgQE8Ffc F8eWKoqAQtn3j4nE3RXbxzTJJfExjFB53vy2wV48fUBdyoXKwE85fiPglQ8bU++0XdOr9oyy j1llZlB9t3tKVv401JAdX8EN0++ETiOovQdzE1m+6ioDCtKEx84ObZJM0yGSEGEanrWjiwsa nzeK0pJQM9EwoEYi8TBGhHC9ksaAAQipSH7F2OHSYIlYtd91QoiemgclZcSgrxKSJhyFhmLr QEiEILTKn/pqJfhHU/7R7UtlDAmFMUp7ByywB4JLcyD10lTmrEJ0iyRRTVfDrfVP82aMBXgF tKQaCxcmLCaEtrSrYGzd1sSPwJne9ssfq0SE/LM1J7VdCjm6OWV33SwKrfd6rOtvOzgadrG6 3bgUVBw+bsXhWDd8tvuCXmdY4bnUblxF2B6GOwSY43v6suugBttIyW5Bl2tXSTwP+zQisOJo +dpVG2pRr39h+buHB3NY83NEPXm1kUOhduJUA17XUY6QQCAaN4sdwPqHq938S3EmtVhsuQIN BFq54uIBEACtPWrRdrvqfwQF+KMieDAMGdWKGSYSfoEGGJ+iNR8v255IyCMkty+yaHafvzpl PFtBQ/D7Fjv+PoHdFq1BnNTk8u2ngfbre9wd9MvTDsyP/TmpF0wyyTXhhtYvE267Av4X/BQT lT9IXKyAf1fP4BGYdTNgQZmAjrRsVUW0j6gFDrN0rq2J9emkGIPvt9rQt6xGzrd6aXonbg5V j6Uac1F42ESOZkIh5cN6cgnGdqAQb8CgLK92Yc8eiCVCH3cGowtzQ2m6U32qf30cBWmzfSH0 HeYmTP9+5L8qSTA9s3z0228vlaY0cFGcXjdodBeVbhqQYseMF9FXiEyRs28uHAJEyvVZwI49 CnAgVV/n1eZa5qOBpBL+ZSURm8Ii0vgfvGSijPGbvc32UAeAmBWISm7QOmc6sWa1tobCiVmY SNzj5MCNk8z4cddoKIc7Wt197+X/X5JPUF5nQRvg3SEHvfjkS4uEst9GwQBpsbQYH9MYWq2P PdxZ+xQE6v7cNB/pGGyXqKjYCm6v70JOzJFmheuUq0Ljnfhfs15DmZaLCGSMC0Amr+rtefpA y9FO5KaARgdhVjP2svc1F9KmTUGinSfuFm3quadGcQbJw+lJNYIfM7PMS9fftq6vCUBoGu3L j4xlgA/uQl/LPneu9mcvit8JqcWGS3fO+YeagUOon1TRqQARAQABiQRsBBgBCAAgFiEEZSrP ibrORRTHQ99dhhM92CvBILkFAlq54uICGwICQAkQhhM92CvBILnBdCAEGQEIAB0WIQQIhvWx rCU+BGX+nH3N7sq0YorTbQUCWrni4gAKCRDN7sq0YorTbVVSD/9V1xkVFyUCZfWlRuryBRZm S4GVaNtiV2nfUfcThQBfF0sSW/aFkLP6y+35wlOGJE65Riw1C2Ca9WQYk0xKvcZrmuYkK3DZ 0M9/Ikkj5/2v0vxz5Z5w/9+IaCrnk7pTnHZuZqOh23NeVZGBls/IDIvvLEjpD5UYicH0wxv+ X6cl1RoP2Kiyvenf0cS73O22qSEw0Qb9SId8wh0+ClWet2E7hkjWFkQfgJ3hujR/JtwDT/8h 3oCZFR0KuMPHRDsCepaqb/k7VSGTLBjVDOmr6/C9FHSjq0WrVB9LGOkdnr/xcISDZcMIpbRm EkIQ91LkT/HYIImL33ynPB0SmA+1TyMgOMZ4bakFCEn1vxB8Ir8qx5O0lHMOiWMJAp/PAZB2 r4XSSHNlXUaWUg1w3SG2CQKMFX7vzA31ZeEiWO8tj/c2ZjQmYjTLlfDK04WpOy1vTeP45LG2 wwtMA1pKvQ9UdbYbovz92oyZXHq81+k5Fj/YA1y2PI4MdHO4QobzgREoPGDkn6QlbJUBf4To pEbIGgW5LRPLuFlOPWHmIS/sdXDrllPc29aX2P7zdD/ivHABslHmt7vN3QY+hG0xgsCO1JG5 pLORF2N5XpM95zxkZqvYfC5tS/qhKyMcn1kC0fcRySVVeR3tUkU8/caCqxOqeMe2B6yTiU1P aNDq25qYFLeYxg67D/4w/P6BvNxNxk8hx6oQ10TOlnmeWp1q0cuutccblU3ryRFLDJSngTEu ZgnOt5dUFuOZxmMkqXGPHP1iOb+YDznHmC0FYZFG2KAc9pO0WuO7uT70lL6larTQrEneTDxQ CMQLP3qAJ/2aBH6SzHIQ7sfbsxy/63jAiHiT3cOaxAKsWkoV2HQpnmPOJ9u02TPjYmdpeIfa X2tXyeBixa3i/6dWJ4nIp3vGQicQkut1YBwR7dJq67/FCV3Mlj94jI0myHT5PIrCS2S8LtWX ikTJSxWUKmh7OP5mrqhwNe0ezgGiWxxvyNwThOHc5JvpzJLd32VDFilbxgu4Hhnf6LcgZJ2c Zd44XWqUu7FzVOYaSgIvTP0hNrBYm/E6M7yrLbs3JY74fGzPWGRbBUHTZXQEqQnZglXaVB5V ZhSFtHopZnBSCUSNDbB+QGy4B/E++Bb02IBTGl/JxmOwG+kZUnymsPvTtnNIeTLHxN/H/ae0 c7E5M+/NpslPCmYnDjs5qg0/3ihh6XuOGggZQOqrYPC3PnsNs3NxirwOkVPQgO6mXxpuifvJ DG9EMkK8IBXnLulqVk54kf7fE0jT/d8RTtJIA92GzsgdK2rpT1MBKKVffjRFGwN7nQVOzi4T XrB5p+6ML7Bd84xOEGsj/vdaXmz1esuH7BOZAGEZfLRCHJ0GVCSssg== Message-ID: Date: Mon, 13 Jul 2020 17:33:21 +1000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200703061844.111865-5-leobras.c@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 03/07/2020 16:18, Leonardo Bras wrote: > On LoPAR "DMA Window Manipulation Calls", it's recommended to remove the > default DMA window for the device, before attempting to configure a DDW, > in order to make the maximum resources available for the next DDW to be > created. > > This is a requirement for using DDW on devices in which hypervisor > allows only one DMA window. > > If setting up a new DDW fails anywhere after the removal of this > default DMA window, it's needed to restore the default DMA window. > For this, an implementation of ibm,reset-pe-dma-windows rtas call is > needed: > > Platforms supporting the DDW option starting with LoPAR level 2.7 implement > ibm,ddw-extensions. The first extension available (index 2) carries the > token for ibm,reset-pe-dma-windows rtas call, which is used to restore > the default DMA window for a device, if it has been deleted. > > It does so by resetting the TCE table allocation for the PE to it's > boot time value, available in "ibm,dma-window" device tree node. > > Signed-off-by: Leonardo Bras > --- > arch/powerpc/platforms/pseries/iommu.c | 83 +++++++++++++++++++++----- > 1 file changed, 69 insertions(+), 14 deletions(-) > > diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c > index 4e33147825cc..5b520ac354c6 100644 > --- a/arch/powerpc/platforms/pseries/iommu.c > +++ b/arch/powerpc/platforms/pseries/iommu.c > @@ -1066,6 +1066,38 @@ static phys_addr_t ddw_memory_hotplug_max(void) > return max_addr; > } > > +/* > + * Platforms supporting the DDW option starting with LoPAR level 2.7 implement > + * ibm,ddw-extensions, which carries the rtas token for > + * ibm,reset-pe-dma-windows. > + * That rtas-call can be used to restore the default DMA window for the device. > + */ > +static void reset_dma_window(struct pci_dev *dev, struct device_node *par_dn) > +{ > + int ret; > + u32 cfg_addr, reset_dma_win; > + u64 buid; > + struct device_node *dn; > + struct pci_dn *pdn; > + > + ret = ddw_read_ext(par_dn, DDW_EXT_RESET_DMA_WIN, &reset_dma_win); > + if (ret) > + return; > + > + dn = pci_device_to_OF_node(dev); > + pdn = PCI_DN(dn); > + buid = pdn->phb->buid; > + cfg_addr = ((pdn->busno << 16) | (pdn->devfn << 8)); > + > + ret = rtas_call(reset_dma_win, 3, 1, NULL, cfg_addr, BUID_HI(buid), > + BUID_LO(buid)); > + if (ret) > + dev_info(&dev->dev, > + "ibm,reset-pe-dma-windows(%x) %x %x %x returned %d ", > + reset_dma_win, cfg_addr, BUID_HI(buid), BUID_LO(buid), > + ret); > +} > + > /* > * If the PE supports dynamic dma windows, and there is space for a table > * that can map all pages in a linear offset, then setup such a table, > @@ -1079,7 +1111,7 @@ static phys_addr_t ddw_memory_hotplug_max(void) > */ > static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn) > { > - int len, ret; > + int len, ret, reset_win_ext; Make it "reset_token". > struct ddw_query_response query; > struct ddw_create_response create; > int page_shift; > @@ -1087,7 +1119,7 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn) > struct device_node *dn; > u32 ddw_avail[DDW_APPLICABLE_SIZE]; > struct direct_window *window; > - struct property *win64; > + struct property *win64, *default_win = NULL; > struct dynamic_dma_window_prop *ddwprop; > struct failed_ddw_pdn *fpdn; > > @@ -1122,7 +1154,7 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn) > if (ret) > goto out_failed; > > - /* > + /* > * Query if there is a second window of size to map the > * whole partition. Query returns number of windows, largest > * block assigned to PE (partition endpoint), and two bitmasks > @@ -1133,14 +1165,34 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn) > if (ret != 0) > goto out_failed; > > + /* > + * If there is no window available, remove the default DMA window, > + * if it's present. This will make all the resources available to the > + * new DDW window. > + * If anything fails after this, we need to restore it, so also check > + * for extensions presence. > + */ > if (query.windows_available == 0) { > - /* > - * no additional windows are available for this device. > - * We might be able to reallocate the existing window, > - * trading in for a larger page size. > - */ > - dev_dbg(&dev->dev, "no free dynamic windows"); > - goto out_failed; > + default_win = of_find_property(pdn, "ibm,dma-window", NULL); > + if (!default_win) > + goto out_failed; > + > + reset_win_ext = ddw_read_ext(pdn, DDW_EXT_RESET_DMA_WIN, NULL); > + if (reset_win_ext) > + goto out_failed; > + > + remove_dma_window(pdn, ddw_avail, default_win); > + > + /* Query again, to check if the window is available */ > + ret = query_ddw(dev, ddw_avail, &query, pdn); > + if (ret != 0) > + goto out_restore_defwin; > + > + if (query.windows_available == 0) { > + /* no windows are available for this device. */ > + dev_dbg(&dev->dev, "no free dynamic windows"); > + goto out_restore_defwin; > + } > } > if (query.page_size & 4) { > page_shift = 24; /* 16MB */ > @@ -1151,7 +1203,7 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn) > } else { > dev_dbg(&dev->dev, "no supported direct page size in mask %x", > query.page_size); > - goto out_failed; > + goto out_restore_defwin; > } > /* verify the window * number of ptes will map the partition */ > /* check largest block * page size > max memory hotplug addr */ > @@ -1160,14 +1212,14 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn) > dev_dbg(&dev->dev, "can't map partition max 0x%llx with %llu " > "%llu-sized pages\n", max_addr, query.largest_available_block, > 1ULL << page_shift); > - goto out_failed; > + goto out_restore_defwin; > } > len = order_base_2(max_addr); > win64 = kzalloc(sizeof(struct property), GFP_KERNEL); > if (!win64) { > dev_info(&dev->dev, > "couldn't allocate property for 64bit dma window\n"); > - goto out_failed; > + goto out_restore_defwin; > } > win64->name = kstrdup(DIRECT64_PROPNAME, GFP_KERNEL); > win64->value = ddwprop = kmalloc(sizeof(*ddwprop), GFP_KERNEL); > @@ -1230,8 +1282,11 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn) > kfree(win64->value); > kfree(win64); > > -out_failed: > +out_restore_defwin: > + if (default_win && reset_win_ext == 0) reset_win_ext potentially may be uninitialized here. Yeah I know it is tied to default_win but still. After looking at this function for a few minutes, it could use some refactoring (way too many gotos) such as: 1. move (query.page_size & xx) checks before "if (query.windows_available == 0)" 2. move "win64 = kzalloc(sizeof(struct property), GFP_KERNEL)" before "if (query.windows_available == 0)" 3. call "reset_dma_window(dev, pdn)" inside the "if (query.windows_available == 0)" branch. Then you can drop all "goto out_restore_defwin" and move default_win and reset_win_ext inside "if (query.windows_available == 0)". The rest of the series is good as it is, however it may conflict with https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20200713062348.100552-1-aik@ozlabs.ru/ and the patchset it is made on top of - https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=188385 . thanks, > + reset_dma_window(dev, pdn); > > +out_failed: > fpdn = kzalloc(sizeof(*fpdn), GFP_KERNEL); > if (!fpdn) > goto out_unlock; > -- Alexey