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Message-ID: <599a72b7-3343-4862-93fe-c6985d20a784@linux.intel.com>
Date: Wed, 28 Feb 2024 11:30:02 +0800
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Cc: baolu.lu@linux.intel.com, "iommu@lists.linux.dev"
 <iommu@lists.linux.dev>,
 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
 Jason Gunthorpe <jgg@nvidia.com>
Subject: Re: [PATCH 1/2] iommu: Add static iommu_ops->release_domain
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To: "Tian, Kevin" <kevin.tian@intel.com>, Joerg Roedel <joro@8bytes.org>,
 Will Deacon <will@kernel.org>, Robin Murphy <robin.murphy@arm.com>,
 Jason Gunthorpe <jgg@ziepe.ca>, "Badger, Eric" <ebadger@purestorage.com>
References: <20240223051302.177596-1-baolu.lu@linux.intel.com>
 <20240223051302.177596-2-baolu.lu@linux.intel.com>
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 <c8bfc031-27a2-464e-b98e-47a7e6a05286@linux.intel.com>
 <BN9PR11MB52766698FA25EA5D397188878C582@BN9PR11MB5276.namprd11.prod.outlook.com>
From: Baolu Lu <baolu.lu@linux.intel.com>
In-Reply-To: <BN9PR11MB52766698FA25EA5D397188878C582@BN9PR11MB5276.namprd11.prod.outlook.com>
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On 2/28/24 11:08 AM, Tian, Kevin wrote:
>> From: Baolu Lu <baolu.lu@linux.intel.com>
>> Sent: Wednesday, February 28, 2024 9:14 AM
>>
>> On 2/27/24 3:32 PM, Tian, Kevin wrote:
>>>> From: Lu Baolu<baolu.lu@linux.intel.com>
>>>> Sent: Friday, February 23, 2024 1:13 PM
>>>>
>>>>
>>>> +	/*
>>>> +	 * If the iommu driver provides release_domain then the core code
>>>> +	 * ensures that domain is attached prior to calling release_device.
>>>> +	 * Drivers can use this to enforce a translation on the idle iommu.
>>> 'enforce a translation' is confusing in the context of blocking/identity
>>> domain.
>>
>> Blocking or identity domain is also kind of a translation from the
>> core's perspective. The core does not care what type of translation the
>> release_domain is; it just enforces this type of translation before
>> device release if the driver has specified one.
>>
> 
> OK.
> 
> btw you may also want to update the following comment together:
> 
> 	/*
> 	 * release_device() must stop using any attached domain on the device.
> 	 * If there are still other devices in the group they are not effected
> 	 * by this callback.
> 	 *
> 	 * The IOMMU driver must set the device to either an identity or
> 	 * blocking translation and stop using any domain pointer, as it is
> 	 * going to be freed.
> 	 */
> 
> all the purpose is to set the device to identity or blocking, either via attaching
> to an explicit release_domain or implicitly by release_device().

Done.

Best regards,
baolu