Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932453AbbFEGhK (ORCPT ); Fri, 5 Jun 2015 02:37:10 -0400 Received: from e23smtp04.au.ibm.com ([202.81.31.146]:53209 "EHLO e23smtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932326AbbFEGhH (ORCPT ); Fri, 5 Jun 2015 02:37:07 -0400 From: Alexey Kardashevskiy To: linuxppc-dev@lists.ozlabs.org Cc: Alexey Kardashevskiy , Alex Williamson , Benjamin Herrenschmidt , David Gibson , Gavin Shan , Paul Mackerras , Wei Yang , linux-kernel@vger.kernel.org Subject: [PATCH kernel v12 07/34] vfio: powerpc/spapr: Check that IOMMU page is fully contained by system page Date: Fri, 5 Jun 2015 16:34:59 +1000 Message-Id: <1433486126-23551-8-git-send-email-aik@ozlabs.ru> X-Mailer: git-send-email 2.4.0.rc3.8.gfb3e7d5 In-Reply-To: <1433486126-23551-1-git-send-email-aik@ozlabs.ru> References: <1433486126-23551-1-git-send-email-aik@ozlabs.ru> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15060506-0013-0000-0000-00000162EB33 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2202 Lines: 69 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 [aw: for the vfio related changes] Acked-by: Alex Williamson Reviewed-by: David Gibson Reviewed-by: Gavin Shan --- Changes: v8: changed subject 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 b95fa2b..735b308 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; @@ -189,6 +199,12 @@ 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) + offset; ret = iommu_tce_build(tbl, entry + i, hva, direction); -- 2.4.0.rc3.8.gfb3e7d5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/