Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <c0e94e88-94b8-69de-69c8-ed132ae28951@linux.intel.com>
Date:   Wed, 9 Aug 2023 18:58:15 +0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101
 Thunderbird/102.14.0
Cc:     baolu.lu@linux.intel.com,
        "iommu@lists.linux.dev" <iommu@lists.linux.dev>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/5] iommu: Call helper function to get assigned pasid
 value
Content-Language: en-US
To:     "Tian, Kevin" <kevin.tian@intel.com>,
        "Zhang, Tina" <tina.zhang@intel.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Michael Shavit <mshavit@google.com>
References: <20230808074944.7825-1-tina.zhang@intel.com>
 <20230808074944.7825-3-tina.zhang@intel.com>
 <f3d8692e-b13d-97ee-2288-c2be1858dcfa@linux.intel.com>
 <BN9PR11MB52767F29A6C11157659D375B8C12A@BN9PR11MB5276.namprd11.prod.outlook.com>
From:   Baolu Lu <baolu.lu@linux.intel.com>
In-Reply-To: <BN9PR11MB52767F29A6C11157659D375B8C12A@BN9PR11MB5276.namprd11.prod.outlook.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 2023/8/9 17:49, Tian, Kevin wrote:
>> From: Baolu Lu <baolu.lu@linux.intel.com>
>> Sent: Wednesday, August 9, 2023 8:22 AM
>>
>> On 2023/8/8 15:49, Tina Zhang wrote:
>>> Use the helper function mm_get_pasid() to get the mm assigned pasid
>>> value.
>>
>> For internal iommu drivers, perhaps we should use another helper.
>> Something like sva_domain_get_pasid()?
>>
>> Suppose that the iommu drivers should have no idea about the "mm".
>>
> 
> Aren't all touched functions accept a struct mm_struct pointer?

In the end we should remove all mm reference in the individual drivers.
The drivers only need to know what they need to know. All mm-aware code
should eventually be moved to the core.

For now, at least we should avoid using mm in the set/remove_dev_pasid
code path. Later, once we complete consolidating mm notification in the
core, drivers will have no need to use "mm" anymore.

Best regards,
baolu