From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753524AbbC0O5M (ORCPT ); Fri, 27 Mar 2015 10:57:12 -0400 Received: from e23smtp04.au.ibm.com ([202.81.31.146]:39984 "EHLO e23smtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752546AbbC0O4g (ORCPT ); Fri, 27 Mar 2015 10:56:36 -0400 From: Alexey Kardashevskiy To: linuxppc-dev@lists.ozlabs.org Cc: Alexey Kardashevskiy , Benjamin Herrenschmidt , Paul Mackerras , Alex Williamson , linux-kernel@vger.kernel.org Subject: [PATCH kernel v7 03/31] vfio: powerpc/spapr: Check that TCE page size is equal to it_page_size Date: Sat, 28 Mar 2015 01:54:47 +1100 Message-Id: <1427468115-2224-4-git-send-email-aik@ozlabs.ru> X-Mailer: git-send-email 2.0.0 In-Reply-To: <1427468115-2224-1-git-send-email-aik@ozlabs.ru> References: <1427468115-2224-1-git-send-email-aik@ozlabs.ru> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15032714-0013-0000-0000-000001021066 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This checks that the TCE table page size is not bigger that the size of a page we just pinned and going to put its physical address to the table. Otherwise the hardware gets unwanted access to physical memory between the end of the actual page and the end of the aligned up TCE page. Since compound_order() and compound_head() work correctly on non-huge pages, there is no need for additional check whether the page is huge. Signed-off-by: Alexey Kardashevskiy --- Changes: v6: * the helper is simplified to one line v4: * s/tce_check_page_size/tce_page_is_contained/ --- drivers/vfio/vfio_iommu_spapr_tce.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c index e9b4d7d..f835e63 100644 --- a/drivers/vfio/vfio_iommu_spapr_tce.c +++ b/drivers/vfio/vfio_iommu_spapr_tce.c @@ -47,6 +47,16 @@ struct tce_container { bool enabled; }; +static bool tce_page_is_contained(struct page *page, unsigned page_shift) +{ + /* + * Check that the TCE table granularity is not bigger than the size of + * a page we just found. Otherwise the hardware can get access to + * a bigger memory chunk that it should. + */ + return (PAGE_SHIFT + compound_order(compound_head(page))) >= page_shift; +} + static int tce_iommu_enable(struct tce_container *container) { int ret = 0; @@ -195,6 +205,12 @@ static long tce_iommu_build(struct tce_container *container, ret = -EFAULT; break; } + + if (!tce_page_is_contained(page, tbl->it_page_shift)) { + ret = -EPERM; + break; + } + hva = (unsigned long) page_address(page) + (tce & IOMMU_PAGE_MASK(tbl) & ~PAGE_MASK); -- 2.0.0