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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 950FDC43381 for ; Wed, 27 Mar 2019 19:07:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 656FF204FD for ; Wed, 27 Mar 2019 19:07:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553713677; bh=Ov1QuUJhEHTF/HRkiW26STtZhdPCawV1qgMKrz3c1AA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=UAqrycvIy7hayC0JkYTbPBdszDY2l6feqBvJ/KMFSfdEURWYAAqNRqLjNsLDCuD/j kPMLqdNGPCmtVdR9DvoVs5/4woVvW80Ku3R3OD8QlcPHNSrfqIawzhFJXcAXmR7nFd 0STwkleHhZH1rV+1EaEJq6btn/2hsh8QPLbqRv1I= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389431AbfC0TH4 (ORCPT ); Wed, 27 Mar 2019 15:07:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:54376 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389122AbfC0SMA (ORCPT ); Wed, 27 Mar 2019 14:12:00 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D5F4E2147C; Wed, 27 Mar 2019 18:11:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553710319; bh=Ov1QuUJhEHTF/HRkiW26STtZhdPCawV1qgMKrz3c1AA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ayofimgkUZ2W/afzvQs3mExkYDP3dYaYEFL4HuU8ZBkEJN7SfScz+O4jdUTww7RUZ bkha8bvbdUCitPspvhviEHLvZuSbgyJsILEibR3NBVDK79Yhym2TVoCqbs4Qfi9J5b Z6aa2WJCGpISE4HsagR3QzVgT2b4PkcfxO0tlN20= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Alexey Kardashevskiy , Michael Ellerman , Sasha Levin , linuxppc-dev@lists.ozlabs.org Subject: [PATCH AUTOSEL 4.19 052/192] powerpc/powernv/ioda: Fix locked_vm counting for memory used by IOMMU tables Date: Wed, 27 Mar 2019 14:08:04 -0400 Message-Id: <20190327181025.13507-52-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190327181025.13507-1-sashal@kernel.org> References: <20190327181025.13507-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alexey Kardashevskiy [ Upstream commit 11f5acce2fa43b015a8120fa7620fa4efd0a2952 ] We store 2 multilevel tables in iommu_table - one for the hardware and one with the corresponding userspace addresses. Before allocating the tables, the iommu_table_group_ops::get_table_size() hook returns the combined size of the two and VFIO SPAPR TCE IOMMU driver adjusts the locked_vm counter correctly. When the table is actually allocated, the amount of allocated memory is stored in iommu_table::it_allocated_size and used to decrement the locked_vm counter when we release the memory used by the table; .get_table_size() and .create_table() calculate it independently but the result is expected to be the same. However the allocator does not add the userspace table size to .it_allocated_size so when we destroy the table because of VFIO PCI unplug (i.e. VFIO container is gone but the userspace keeps running), we decrement locked_vm by just a half of size of memory we are releasing. To make things worse, since we enabled on-demand allocation of indirect levels, it_allocated_size contains only the amount of memory actually allocated at the table creation time which can just be a fraction. It is not a problem with incrementing locked_vm (as get_table_size() value is used) but it is with decrementing. As the result, we leak locked_vm and may not be able to allocate more IOMMU tables after few iterations of hotplug/unplug. This sets it_allocated_size in the pnv_pci_ioda2_ops::create_table() hook to what pnv_pci_ioda2_get_table_size() returns so from now on we have a single place which calculates the maximum memory a table can occupy. The original meaning of it_allocated_size is somewhat lost now though. We do not ditch it_allocated_size whatsoever here and we do not call get_table_size() from vfio_iommu_spapr_tce.c when decrementing locked_vm as we may have multiple IOMMU groups per container and even though they all are supposed to have the same get_table_size() implementation, there is a small chance for failure or confusion. Fixes: 090bad39b237 ("powerpc/powernv: Add indirect levels to it_userspace") Signed-off-by: Alexey Kardashevskiy Reviewed-by: David Gibson Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin --- arch/powerpc/platforms/powernv/pci-ioda-tce.c | 1 - arch/powerpc/platforms/powernv/pci-ioda.c | 7 ++++++- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/powernv/pci-ioda-tce.c b/arch/powerpc/platforms/powernv/pci-ioda-tce.c index 7639b2168755..f5adb6b756f7 100644 --- a/arch/powerpc/platforms/powernv/pci-ioda-tce.c +++ b/arch/powerpc/platforms/powernv/pci-ioda-tce.c @@ -313,7 +313,6 @@ long pnv_pci_ioda2_table_alloc_pages(int nid, __u64 bus_offset, page_shift); tbl->it_level_size = 1ULL << (level_shift - 3); tbl->it_indirect_levels = levels - 1; - tbl->it_allocated_size = total_allocated; tbl->it_userspace = uas; tbl->it_nid = nid; diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c index cde710297a4e..326ca6288bb1 100644 --- a/arch/powerpc/platforms/powernv/pci-ioda.c +++ b/arch/powerpc/platforms/powernv/pci-ioda.c @@ -2603,8 +2603,13 @@ static long pnv_pci_ioda2_create_table_userspace( int num, __u32 page_shift, __u64 window_size, __u32 levels, struct iommu_table **ptbl) { - return pnv_pci_ioda2_create_table(table_group, + long ret = pnv_pci_ioda2_create_table(table_group, num, page_shift, window_size, levels, true, ptbl); + + if (!ret) + (*ptbl)->it_allocated_size = pnv_pci_ioda2_get_table_size( + page_shift, window_size, levels); + return ret; } static void pnv_ioda2_take_ownership(struct iommu_table_group *table_group) -- 2.19.1