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From: Yi Liu <yi.l.liu@intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>, Baolu Lu <baolu.lu@linux.intel.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
	"joro@8bytes.org" <joro@8bytes.org>,
	"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
	"robin.murphy@arm.com" <robin.murphy@arm.com>,
	"eric.auger@redhat.com" <eric.auger@redhat.com>,
	"nicolinc@nvidia.com" <nicolinc@nvidia.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"chao.p.peng@linux.intel.com" <chao.p.peng@linux.intel.com>,
	"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
	"Duan, Zhenzhong" <zhenzhong.duan@intel.com>,
	"Pan, Jacob jun" <jacob.jun.pan@intel.com>
Subject: Re: [PATCH v2 12/12] iommu/vt-d: Add set_dev_pasid callback for nested domain
Date: Tue, 7 May 2024 10:28:34 +0800	[thread overview]
Message-ID: <14a7b83e-0e5b-4518-a5d5-5f4d48aa6f2b@intel.com> (raw)
In-Reply-To: <20240506133635.GJ3341011@nvidia.com>

On 2024/5/6 21:36, Jason Gunthorpe wrote:
> On Mon, May 06, 2024 at 03:42:21PM +0800, Baolu Lu wrote:
>> On 2024/4/30 17:19, Yi Liu wrote:
>>> On 2024/4/17 17:25, Tian, Kevin wrote:
>>>>> From: Liu, Yi L <yi.l.liu@intel.com>
>>>>> Sent: Friday, April 12, 2024 4:15 PM
>>>>>
>>>>> From: Lu Baolu <baolu.lu@linux.intel.com>
>>>>>
>>>>> This allows the upper layers to set a nested type domain to a PASID of a
>>>>> device if the PASID feature is supported by the IOMMU hardware.
>>>>>
>>>>> The set_dev_pasid callback for non-nested domain has already be
>>>>> there, so
>>>>> this only needs to add it for nested domains. Note that the S2
>>>>> domain with
>>>>> dirty tracking capability is not supported yet as no user for now.
>>>>
>>>> S2 domain does support dirty tracking. Do you mean the specific
>>>> check in intel_iommu_set_dev_pasid() i.e. pasid-granular dirty
>>>> tracking is not supported yet?
>>>
>>> yes. We may remove this check when real usage comes. e.g. SIOV.
>>>
>>>>> +static int intel_nested_set_dev_pasid(struct iommu_domain *domain,
>>>>> +                      struct device *dev, ioasid_t pasid,
>>>>> +                      struct iommu_domain *old)
>>>>> +{
>>>>> +    struct device_domain_info *info = dev_iommu_priv_get(dev);
>>>>> +    struct dmar_domain *dmar_domain = to_dmar_domain(domain);
>>>>> +    struct intel_iommu *iommu = info->iommu;
>>>>> +
>>>>> +    if (iommu->agaw < dmar_domain->s2_domain->agaw)
>>>>> +        return -EINVAL;
>>>>> +
>>>>
>>>> this check is covered by prepare_domain_attach_device() already.
>>>
>>> This was added to avoid modifying the s2_domain's agaw. I'm fine to remove
>>> it personally as the existing attach path also needs to update domain's
>>> agaw per device attachment. @Baolu, how about your opinion?
>>
>> We still need something to do before we can safely remove this check.
>> All the domain allocation interfaces should eventually have the device
>> pointer as the input, and all domain attributions could be initialized
>> during domain allocation. In the attach paths, it should return -EINVAL
>> directly if the domain is not compatible with the iommu for the device.
> 
> Yes, and this is already true for PASID.

I'm not quite get why it is already true for PASID. I think Baolu's remark
is general to domains attached to either RID or PASID.

> I feel we could reasonably insist that domanis used with PASID are
> allocated with a non-NULL dev.

Any special reason for this disclaim?

> 
> If so it means we need to fixup the domain allocation in iommufd as
> part of the pasid series, and Intel will have to implement
> alloc_domain_paging().

I agree implementing alloc_domain_paging() is the final solution to avoid
such dynamic modifications to domain's caps. If it's really needed for
PASID series now, I can add it in next version. :)

-- 
Regards,
Yi Liu

  reply	other threads:[~2024-05-07  2:25 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-12  8:15 [PATCH v2 00/12] iommufd support pasid attach/replace Yi Liu
2024-04-12  8:15 ` [PATCH v2 01/12] iommu: Pass old domain to set_dev_pasid op Yi Liu
2024-04-15  5:32   ` Baolu Lu
2024-04-15 11:54     ` Jason Gunthorpe
2024-04-16  2:07       ` Baolu Lu
2024-04-16 17:47         ` Jason Gunthorpe
2024-04-12  8:15 ` [PATCH v2 02/12] iommu: Introduce a replace API for device pasid Yi Liu
2024-04-16  3:01   ` Duan, Zhenzhong
2024-04-16  9:18     ` Yi Liu
2024-04-17  8:44   ` Tian, Kevin
2024-04-17 12:17     ` Jason Gunthorpe
2024-04-18  0:08       ` Tian, Kevin
2024-04-29 13:55   ` Jason Gunthorpe
2024-04-30  5:00     ` Yi Liu
2024-04-30 12:26       ` Jason Gunthorpe
2024-04-12  8:15 ` [PATCH v2 03/12] iommufd: replace attach_fn with a structure Yi Liu
2024-04-12  8:15 ` [PATCH v2 04/12] iommufd: Support attach/replace hwpt per pasid Yi Liu
2024-04-29 13:56   ` Jason Gunthorpe
2024-04-12  8:15 ` [PATCH v2 05/12] iommu: Allow iommu driver to populate the max_pasids Yi Liu
2024-04-15  5:41   ` Baolu Lu
2024-04-17  8:49     ` Tian, Kevin
2024-04-20  5:45       ` Yi Liu
2024-04-22 11:52         ` Jason Gunthorpe
2024-04-12  8:15 ` [PATCH v2 06/12] iommufd/selftest: Add set_dev_pasid and remove_dev_pasid in mock iommu Yi Liu
2024-04-12  8:15 ` [PATCH v2 07/12] iommufd/selftest: Add a helper to get test device Yi Liu
2024-04-12  8:15 ` [PATCH v2 08/12] iommufd/selftest: Add test ops to test pasid attach/detach Yi Liu
2024-04-12  8:15 ` [PATCH v2 09/12] iommufd/selftest: Add coverage for iommufd " Yi Liu
2024-04-12  8:15 ` [PATCH v2 10/12] iommu/vt-d: Return if no dev_pasid is found in domain Yi Liu
2024-04-15  6:04   ` Baolu Lu
2024-04-16  9:21     ` Yi Liu
2024-04-17  2:30       ` Baolu Lu
2024-04-17  3:48         ` Yi Liu
2024-04-17  9:03   ` Tian, Kevin
2024-04-17  9:36     ` Yi Liu
2024-04-12  8:15 ` [PATCH v2 11/12] iommu/vt-d: Make intel_iommu_set_dev_pasid() to handle domain replacement Yi Liu
2024-04-17  9:19   ` Tian, Kevin
2024-04-17  9:35     ` Yi Liu
2024-04-17 12:19       ` Jason Gunthorpe
2024-04-12  8:15 ` [PATCH v2 12/12] iommu/vt-d: Add set_dev_pasid callback for nested domain Yi Liu
2024-04-17  9:25   ` Tian, Kevin
2024-04-30  9:19     ` Yi Liu
2024-05-06  7:42       ` Baolu Lu
2024-05-06 13:36         ` Jason Gunthorpe
2024-05-07  2:28           ` Yi Liu [this message]
2024-05-07 15:18             ` Jason Gunthorpe
2024-05-08  6:10               ` Yi Liu
2024-05-08 12:25                 ` Jason Gunthorpe
2024-05-08 13:26                   ` Yi Liu
2024-05-08 14:11                     ` Jason Gunthorpe
2024-05-09 14:22                       ` Liu, Yi L

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