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From: Baolu Lu <baolu.lu@linux.intel.com>
To: Ethan Zhao <haifeng.zhao@linux.intel.com>, iommu@lists.linux.dev
Cc: baolu.lu@linux.intel.com, Joerg Roedel <joro@8bytes.org>,
	Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Kevin Tian <kevin.tian@intel.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] iommu/vt-d: Enable PASID during iommu device probe
Date: Fri, 16 Sep 2022 11:05:47 +0800	[thread overview]
Message-ID: <fc1f5412-6041-71b8-2a87-84f2f32456fc@linux.intel.com> (raw)
In-Reply-To: <78ec0fab-6f69-1d3d-86f3-84f159817707@linux.intel.com>

On 2022/9/16 10:40, Ethan Zhao wrote:
>>
>> I may not get you exactly. 😄 Some IOMMU features reply on PASID
>> capabilities on both IOMMU and device. The IOMMU drivers enumerate the
>> capabilities and enable them if they are supported.
> I might not express it straightforward,  I mean with this patch iommu 
> deals with
> 
> the complexity of enabling PASID (globally?)  or not at probing stage , 
> instead
> 
> of other device driver side decision to request IOMMU PASID enabling during
> 
> their setup state.  if so you move the decision to iommu probe stage. 
> hmmm...

I am sorry that the commit message was a bit confusing. Actually we
always enable PASID at iommu probe path w/ or w/o this patch.

> 
> Pros,  iommu driver controls everything about PASID enabling.
> 
> Cons,  iommu driver handles all possible complexity about capability 
> matching

Do device drivers need to configure PCI PASID without IOMMU? I searched
the tree and found nothing.

Best regards,
baolu

  reply	other threads:[~2022-09-16  3:07 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-12  2:48 [PATCH 1/1] iommu/vt-d: Enable PASID during iommu device probe Lu Baolu
2022-09-13  3:13 ` Tian, Kevin
2022-09-13  6:01   ` Baolu Lu
2022-09-13  7:42     ` Tian, Kevin
2022-09-13  7:46 ` Ethan Zhao
2022-09-13  9:30   ` Baolu Lu
     [not found]     ` <e26efaee-d84a-3b60-8400-90d8e49a9b25@linux.intel.com>
2022-09-15  3:00       ` Baolu Lu
2022-09-16  2:40         ` Ethan Zhao
2022-09-16  3:05           ` Baolu Lu [this message]
2022-09-16  3:37             ` Ethan Zhao
     [not found]             ` <a6ac5953-7372-9894-58d4-d1ee2905d4dd@linux.intel.com>
2022-09-16  4:01               ` Baolu Lu
2022-09-13  8:01 ` Tian, Kevin
2022-09-13  9:25   ` Baolu Lu
2022-09-15  3:22     ` Tian, Kevin
2022-09-15  7:21       ` Baolu Lu

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