Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754690AbbEKPlB (ORCPT ); Mon, 11 May 2015 11:41:01 -0400 Received: from e23smtp06.au.ibm.com ([202.81.31.148]:56030 "EHLO e23smtp06.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754582AbbEKPkv (ORCPT ); Mon, 11 May 2015 11:40:51 -0400 From: Alexey Kardashevskiy To: linuxppc-dev@lists.ozlabs.org Cc: Alexey Kardashevskiy , David Gibson , Benjamin Herrenschmidt , Paul Mackerras , Alex Williamson , Gavin Shan , Wei Yang , linux-kernel@vger.kernel.org Subject: [PATCH kernel v10 07/34] vfio: powerpc/spapr: Check that IOMMU page is fully contained by system page Date: Tue, 12 May 2015 01:38:56 +1000 Message-Id: <1431358763-24371-8-git-send-email-aik@ozlabs.ru> X-Mailer: git-send-email 2.4.0.rc3.8.gfb3e7d5 In-Reply-To: <1431358763-24371-1-git-send-email-aik@ozlabs.ru> References: <1431358763-24371-1-git-send-email-aik@ozlabs.ru> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15051115-0021-0000-0000-000001377F24 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2150 Lines: 68 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 --- 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/