From patchwork Wed Jul 17 22:47:15 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 259861 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 554522C008C for ; Thu, 18 Jul 2013 08:58:22 +1000 (EST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1Uzafn-0000ni-LC; Wed, 17 Jul 2013 22:58:15 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1Uzabt-00084K-JJ for kernel-team@lists.ubuntu.com; Wed, 17 Jul 2013 22:54:13 +0000 Received: from c-67-160-231-162.hsd1.ca.comcast.net ([67.160.231.162] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1UzaWf-0008FQ-Jw; Wed, 17 Jul 2013 22:48:49 +0000 Received: from kamal by fourier with local (Exim 4.80) (envelope-from ) id 1UzaWd-0002SQ-Fv; Wed, 17 Jul 2013 15:48:47 -0700 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 103/145] iommu/amd: Only unmap large pages from the first pte Date: Wed, 17 Jul 2013 15:47:15 -0700 Message-Id: <1374101277-7915-104-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1374101277-7915-1-git-send-email-kamal@canonical.com> References: <1374101277-7915-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.8 Cc: Kamal Mostafa , Alex Williamson , Joerg Roedel X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.8.13.5 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Alex Williamson commit 60d0ca3cfd199b6612bbbbf4999a3470dad38bb1 upstream. If we use a large mapping, the expectation is that only unmaps from the first pte in the superpage are supported. Unmaps from offsets into the superpage should fail (ie. return zero sized unmap). In the current code, unmapping from an offset clears the size of the full mapping starting from an offset. For instance, if we map a 16k physically contiguous range at IOVA 0x0 with a large page, then attempt to unmap 4k at offset 12k, 4 ptes are cleared (12k - 28k) and the unmap returns 16k unmapped. This potentially incorrectly clears valid mappings and confuses drivers like VFIO that use the unmap size to release pinned pages. Fix by refusing to unmap from offsets into the page. Signed-off-by: Alex Williamson Signed-off-by: Joerg Roedel Signed-off-by: Kamal Mostafa --- drivers/iommu/amd_iommu.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index 409b171..895902e6 100644 --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -1508,6 +1508,10 @@ static unsigned long iommu_unmap_page(struct protection_domain *dom, /* Large PTE found which maps this address */ unmap_size = PTE_PAGE_SIZE(*pte); + + /* Only unmap from the first pte in the page */ + if ((unmap_size - 1) & bus_addr) + break; count = PAGE_SIZE_PTE_COUNT(unmap_size); for (i = 0; i < count; i++) pte[i] = 0ULL; @@ -1517,7 +1521,7 @@ static unsigned long iommu_unmap_page(struct protection_domain *dom, unmapped += unmap_size; } - BUG_ON(!is_power_of_2(unmapped)); + BUG_ON(unmapped && !is_power_of_2(unmapped)); return unmapped; }