From patchwork Tue Jan 5 19:42:30 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 563321 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 8AF0E140324; Wed, 6 Jan 2016 06:47:35 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1aGXZq-0002ur-GO; Tue, 05 Jan 2016 19:47:30 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1aGXYy-0002M7-0k for kernel-team@lists.ubuntu.com; Tue, 05 Jan 2016 19:46:36 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1aGXYx-0005gb-Jq; Tue, 05 Jan 2016 19:46:35 +0000 Received: from kamal by fourier with local (Exim 4.82) (envelope-from ) id 1aGXYu-0006nL-ST; Tue, 05 Jan 2016 11:46:32 -0800 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 4.2.y-ckt 042/211] iommu/vt-d: Fix ATSR handling for Root-Complex integrated endpoints Date: Tue, 5 Jan 2016 11:42:30 -0800 Message-Id: <1452023119-25647-43-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1452023119-25647-1-git-send-email-kamal@canonical.com> References: <1452023119-25647-1-git-send-email-kamal@canonical.com> MIME-Version: 1.0 X-Extended-Stable: 4.2 Cc: Kamal Mostafa , David Woodhouse 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: , Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 4.2.8-ckt1 -stable review patch. If anyone has any objections, please let me know. ------------------ From: David Woodhouse commit d14053b3c714178525f22660e6aaf41263d00056 upstream. The VT-d specification says that "Software must enable ATS on endpoint devices behind a Root Port only if the Root Port is reported as supporting ATS transactions." We walk up the tree to find a Root Port, but for integrated devices we don't find one — we get to the host bridge. In that case we *should* allow ATS. Currently we don't, which means that we are incorrectly failing to use ATS for the integrated graphics. Fix that. We should never break out of this loop "naturally" with bus==NULL, since we'll always find bridge==NULL in that case (and now return 1). So remove the check for (!bridge) after the loop, since it can never happen. If it did, it would be worthy of a BUG_ON(!bridge). But since it'll oops anyway in that case, that'll do just as well. Signed-off-by: David Woodhouse Signed-off-by: Kamal Mostafa --- drivers/iommu/intel-iommu.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index bd1b8ad..66e94b8 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -4231,14 +4231,17 @@ int dmar_find_matched_atsr_unit(struct pci_dev *dev) dev = pci_physfn(dev); for (bus = dev->bus; bus; bus = bus->parent) { bridge = bus->self; - if (!bridge || !pci_is_pcie(bridge) || + /* If it's an integrated device, allow ATS */ + if (!bridge) + return 1; + /* Connected via non-PCIe: no ATS */ + if (!pci_is_pcie(bridge) || pci_pcie_type(bridge) == PCI_EXP_TYPE_PCI_BRIDGE) return 0; + /* If we found the root port, look it up in the ATSR */ if (pci_pcie_type(bridge) == PCI_EXP_TYPE_ROOT_PORT) break; } - if (!bridge) - return 0; rcu_read_lock(); list_for_each_entry_rcu(atsru, &dmar_atsr_units, list) {