Re: [dpdk-dev] [PATCH] eal: disable IOVA mode detection by default

[Ferruh Yigit <ferruh.yigit@intel.com>]

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
>