From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e37.co.us.ibm.com (e37.co.us.ibm.com [32.97.110.158]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 0B06D1A0CEB for ; Tue, 24 Feb 2015 05:55:34 +1100 (AEDT) Received: from /spool/local by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 23 Feb 2015 11:55:32 -0700 Received: from b03cxnp07029.gho.boulder.ibm.com (b03cxnp07029.gho.boulder.ibm.com [9.17.130.16]) by d03dlp02.boulder.ibm.com (Postfix) with ESMTP id 9FE743E40041 for ; Mon, 23 Feb 2015 11:55:30 -0700 (MST) Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by b03cxnp07029.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t1NItMCZ54067220 for ; Mon, 23 Feb 2015 11:55:30 -0700 Received: from d03av03.boulder.ibm.com (localhost [127.0.0.1]) by d03av03.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t1NIst1M031666 for ; Mon, 23 Feb 2015 11:54:57 -0700 Date: Mon, 23 Feb 2015 10:54:29 -0800 From: Nishanth Aravamudan To: Michael Ellerman Subject: Re: [v2] pseries/iommu: remove iommu device references via bus notifier Message-ID: <20150223185429.GA54252@linux.vnet.ibm.com> References: <20150221190050.GA20184@linux.vnet.ibm.com> <20150223022724.7884914012C@ozlabs.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20150223022724.7884914012C@ozlabs.org> Cc: linuxppc-dev@lists.ozlabs.org, Alexey Kardashevskiy List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 23.02.2015 [13:27:24 +1100], Michael Ellerman wrote: > On Sat, 2015-21-02 at 19:00:50 UTC, Nishanth Aravamudan wrote: > > On 20.02.2015 [15:31:29 +1100], Michael Ellerman wrote: > > > On Thu, 2015-02-19 at 10:41 -0800, Nishanth Aravamudan wrote: > > > > After d905c5df9aef ("PPC: POWERNV: move iommu_add_device earlier"), the > > > > refcnt on the kobject backing the IOMMU group for a PCI device is > > > > elevated by each call to pci_dma_dev_setup_pSeriesLP() (via > > > > set_iommu_table_base_and_group). When we go to dlpar a multi-function > > > > PCI device out: > > > > > > > > iommu_reconfig_notifier -> > > > > iommu_free_table -> > > > > iommu_group_put > > > > BUG_ON(tbl->it_group) > > > > > > > > We trip this BUG_ON, because there are still references on the table, so > > > > it is not freed. Fix this by also adding a bus notifier identical to > > > > PowerNV for pSeries. > > > > > > Please put it somewhere common, arch/powerpc/kernel/iommu.c perhaps, and just > > > add a second machine_init_call() for pseries. > > > > How does this look? Only compile-tested with CONFIG_IOMMU_API on/off so > > far, waiting for access to the test LPAR (should have it on Monday). > > Yeah that looks better, thanks. > > It probably doesn't build with CONFIG_PCI=n though, but I don't think > CONFIG_PCI=n builds anyway. Indeed it doesn't. Started looking at CONFIG_PCI=n and immediately hit the following: PCI_MSI depends on PCI PCI can be manually turned off PSERIES (and a bunch of other platforms) select PCI_MSI So you end up with PCI_MSI on and PCI off and the build breaks. Should the platforms depend on PCI_MSI instead? Per the Documentation: " select should be used with care. select will force a symbol to a value without visiting the dependencies. By abusing select you are able to select a symbol FOO even if FOO depends on BAR that is not set." Thanks, Nish