Re: [dpdk-dev] [PATCH v2 2/2] vhost: enable IOMMU for async vhost

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 9/24/21 03:53, Xia, Chenbo wrote:
>> -----Original Message-----
>> From: Maxime Coquelin <maxime.coquelin@redhat.com>
>> Sent: Thursday, September 23, 2021 10:56 PM
>> To: Hu, Jiayu <jiayu.hu@intel.com>; Ding, Xuan <xuan.ding@intel.com>;
>> dev@dpdk.org; Burakov, Anatoly <anatoly.burakov@intel.com>; Xia, Chenbo
>> <chenbo.xia@intel.com>
>> Cc: Jiang, Cheng1 <cheng1.jiang@intel.com>; Richardson, Bruce
>> <bruce.richardson@intel.com>; Pai G, Sunil <sunil.pai.g@intel.com>; Wang,
>> Yinan <yinan.wang@intel.com>; Yang, YvonneX <yvonnex.yang@intel.com>
>> Subject: Re: [PATCH v2 2/2] vhost: enable IOMMU for async vhost
>>
>>
>>
>> On 9/23/21 16:39, Hu, Jiayu wrote:
>>> Hi Xuan,
>>>
>>>> -----Original Message-----
>>>> From: Ding, Xuan <xuan.ding@intel.com>
>>>> Sent: Friday, September 17, 2021 1:26 PM
>>>> To: dev@dpdk.org; Burakov, Anatoly <anatoly.burakov@intel.com>;
>>>> maxime.coquelin@redhat.com; Xia, Chenbo <chenbo.xia@intel.com>
>>>> Cc: Hu, Jiayu <jiayu.hu@intel.com>; Jiang, Cheng1 <cheng1.jiang@intel.com>;
>>>> Richardson, Bruce <bruce.richardson@intel.com>; Pai G, Sunil
>>>> <sunil.pai.g@intel.com>; Wang, Yinan <yinan.wang@intel.com>; Yang,
>>>> YvonneX <yvonnex.yang@intel.com>; Ding, Xuan <xuan.ding@intel.com>
>>>> Subject: [PATCH v2 2/2] vhost: enable IOMMU for async vhost
>>>>
>>>> The use of IOMMU has many advantages, such as isolation and address
>>>> translation. This patch extends the capbility of DMA engine to use IOMMU if
>>>> the DMA engine is bound to vfio.
>>>>
>>>> When set memory table, the guest memory will be mapped into the default
>>>> container of DPDK.
>>>>
>>>> Signed-off-by: Xuan Ding <xuan.ding@intel.com>
>>>> ---
>>>>    lib/vhost/rte_vhost.h  |  1 +
>>>>    lib/vhost/vhost_user.c | 57
>>>> +++++++++++++++++++++++++++++++++++++++++-
>>>>    2 files changed, 57 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/lib/vhost/rte_vhost.h b/lib/vhost/rte_vhost.h index
>>>> 8d875e9322..e0537249f3 100644
>>>> --- a/lib/vhost/rte_vhost.h
>>>> +++ b/lib/vhost/rte_vhost.h
>>>> @@ -127,6 +127,7 @@ struct rte_vhost_mem_region {
>>>>    	void	 *mmap_addr;
>>>>    	uint64_t mmap_size;
>>>>    	int fd;
>>>> +	uint64_t dma_map_success;
>>>
>>> How about using bool for dma_map_success?
>>
>> The bigger problem here is that you are breaking the ABI.
> 
> Maybe this kind of driver-facing structs/functions should be removed
> from ABI, since we are refactoring DPDK ABI recently.

It has actually been exposed for SPDK, we cannot just remove it from
API.

Maxime

> /Chenbo
> 
>>
>>>>    };
>>>>
>>>>    /**
>