From mboxrd@z Thu Jan  1 00:00:00 1970
From: Rosen Xu <rosen.xu@intel.com>
Subject: [PATCH v2] doc/guides/rel_notes: Add known issue for
	IOMMU attributes read
Date: Wed, 16 May 2018 15:29:12 +0800
Message-ID: <1526455752-147108-1-git-send-email-rosen.xu@intel.com>
References: <1526294652-102665-1-git-send-email-rosen.xu@intel.com>
Cc: anatoly.burakov@intel.com, gaetan.rivet@6wind.com, john.mcnamara@intel.com,
 rosen.xu@intel.com, yulong.pei@intel.com, stable@dpdk.org
To: dev@dpdk.org
Return-path: <dev-bounces@dpdk.org>
In-Reply-To: <1526294652-102665-1-git-send-email-rosen.xu@intel.com>
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <https://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <https://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

Linux kernel 4.10.0 iommu attribute read error

Cc: stable@dpdk.org

Signed-off-by: Rosen Xu <rosen.xu@intel.com>

v2 updates:
===========
 - Fixed Anatoly comments
---
 doc/guides/rel_notes/known_issues.rst | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/doc/guides/rel_notes/known_issues.rst b/doc/guides/rel_notes/known_issues.rst
index afcc2c4..716bd73 100644
--- a/doc/guides/rel_notes/known_issues.rst
+++ b/doc/guides/rel_notes/known_issues.rst
@@ -714,3 +714,28 @@ igb_uio can not be used when running l3fwd-power
 
 **Driver/Module**:
    ``igb_uio`` module.
+
+
+Linux kernel 4.10.0 iommu attribute read error
+----------------------------------------------
+
+**Description**:
+   When VT-d is enabled (``iommu=pt intel_iommu=on``), reading IOMMU attributes from
+   /sys/devices/virtual/iommu/dmarXXX/intel-iommu/cap on Linux kernel 4.10.0 error.
+   This bug is fixed in `Linux commmit a7fdb6e648fb
+   <https://patchwork.kernel.org/patch/9595727/>`_,
+   This bug is introduced in `Linux commmit 39ab9555c241
+   <https://patchwork.kernel.org/patch/9554403/>`_,
+
+**Implication**:
+   When binding devices to VFIO and attempting to run testpmd application,
+   testpmd (and other DPDK applications) will not initialize.
+
+**Resolution/Workaround**:
+   Use other linux kernel version. It only happens in linux kernel 4.10.0.
+
+**Affected Environment/Platform**:
+   ALL OS of linux kernel 4.10.0.
+
+**Driver/Module**:
+   ``vfio-pci`` module.
-- 
1.8.3.1