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Date:   Wed, 29 Mar 2023 14:22:50 +0800
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        "Luck, Tony" <tony.luck@intel.com>,
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Subject: Re: [PATCH v2 6/8] iommu/vt-d: Implement set_dev_pasid domain op
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To:     Jacob Pan <jacob.jun.pan@linux.intel.com>,
        "Tian, Kevin" <kevin.tian@intel.com>
References: <20230327232138.1490712-1-jacob.jun.pan@linux.intel.com>
 <20230327232138.1490712-7-jacob.jun.pan@linux.intel.com>
 <BN9PR11MB5276B3FF6D21608BB17E32A18C889@BN9PR11MB5276.namprd11.prod.outlook.com>
 <20230328084015.5c8c08ca@jacob-builder>
From:   Baolu Lu <baolu.lu@linux.intel.com>
In-Reply-To: <20230328084015.5c8c08ca@jacob-builder>
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On 3/28/23 11:40 PM, Jacob Pan wrote:
> Hi Kevin,
> 
> On Tue, 28 Mar 2023 07:47:45 +0000, "Tian, Kevin" <kevin.tian@intel.com>
> wrote:
> 
>>> From: Jacob Pan <jacob.jun.pan@linux.intel.com>
>>> Sent: Tuesday, March 28, 2023 7:22 AM
>>>
>>> Devices that use ENQCMDS to submit work on buffers mapped by DMA API
>>> must attach a PASID to the default domain of the device. In preparation
>>> for this use case, this patch implements set_dev_pasid() for the
>>> default_domain_ops. Besides PASID attachment, device will also be
>>> attached to the domain as the result of this call if the device has not
>>> been attached before.
>>>    
>>
>> I didn't get the last point. PASID attach should only have the scope
>> for the pasid. RID of the device might be attached to another domain
>> which shouldn't be changed by this call.
> I meant if the RID context has not been set up before attaching this PASID,
> this call will also set up the context, PASID dir etc. In the end, we
> eliminated ordering requirement of attaching device, RID_PASID first, then
> other PASIDs.

This occurs in default domain deferred attaching case.

> How about:
> "If the device context has not been set up prior to this call, this will
> set up the device context in addition to PASID attachment."

Best regards,
baolu