From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ferruh Yigit <ferruh.yigit@intel.com>
Subject: Re: [PATCH] eal: disable IOVA mode detection by default
Date: Tue, 31 Oct 2017 23:32:45 -0700
Message-ID: <9339bd0d-b9be-21ef-5aa8-1f5b8b5af11f@intel.com>
References: <20171101010726.17781-1-ferruh.yigit@intel.com>
 <ED26CBA2FAD1BF48A8719AEF02201E3651338096@SHSMSX103.ccr.corp.intel.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Cc: "dev@dpdk.org" <dev@dpdk.org>,
 Santosh Shukla <santosh.shukla@caviumnetworks.com>
To: "Tan, Jianfeng" <jianfeng.tan@intel.com>,
 Thomas Monjalon <thomas@monjalon.net>,
 "Richardson, Bruce" <bruce.richardson@intel.com>,
 "Gonzalez Monroy, Sergio" <sergio.gonzalez.monroy@intel.com>
Return-path: <dev-bounces@dpdk.org>
Received: from mga01.intel.com (mga01.intel.com [192.55.52.88])
 by dpdk.org (Postfix) with ESMTP id 7C8971B281
 for <dev@dpdk.org>; Wed,  1 Nov 2017 07:32:47 +0100 (CET)
In-Reply-To: <ED26CBA2FAD1BF48A8719AEF02201E3651338096@SHSMSX103.ccr.corp.intel.com>
Content-Language: en-US
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <http://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: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

On 10/31/2017 7:17 PM, Tan, Jianfeng wrote:
> 
> 
>> -----Original Message-----
>> From: Yigit, Ferruh
>> Sent: Wednesday, November 1, 2017 9:07 AM
>> To: Thomas Monjalon; Richardson, Bruce; Gonzalez Monroy, Sergio
>> Cc: dev@dpdk.org; Yigit, Ferruh; Tan, Jianfeng; Santosh Shukla
>> Subject: [PATCH] eal: disable IOVA mode detection by default
>>
>> Fix kernel crash with KNI because KNI requires physical addresses.
>>
>> A config option introduced to disable IOVA mode detection and to set it
>> to physical address by default. Disabling config option will enable IOVA
>> mode detection.
>>
>> When there is no intension to use KNI, it is safe to enable detection.
>>
>> Config option disable IOVA mode detection by default to be sure only who
>> is aware of result enable it.
>>
>> Fixes: 72d013644bd6 ("mem: honor IOVA mode in malloc virt2phy")
>>
>> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
>> ---
>> Cc: Jianfeng Tan <jianfeng.tan@intel.com>
>> Cc: Santosh Shukla <santosh.shukla@caviumnetworks.com>
>> Cc: Thomas Monjalon <thomas@monjalon.net>
> 
> Refer to how vhost-kernel works, we may leverage a memory region table to do the translation. The bad side is it's less efficient than current phys_to_virt.

Hi Jianfeng,

Can you please elaborate?

Thanks,
ferruh

> Another side, we did not check the result of phys_to_virt, that's why kernel crashes.
> 
> Thanks,
> Jianfeng
>