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From: Lu Baolu <baolu.lu@linux.intel.com>
To: "Tian, Kevin" <kevin.tian@intel.com>,
	Joerg Roedel <joro@8bytes.org>, Jason Gunthorpe <jgg@nvidia.com>,
	Christoph Hellwig <hch@infradead.org>,
	"Raj, Ashok" <ashok.raj@intel.com>, Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"Pan, Jacob jun" <jacob.jun.pan@intel.com>
Subject: Re: [PATCH RFC v3 02/12] iommu: Add a flag to indicate immutable singleton group
Date: Tue, 12 Apr 2022 21:10:03 +0800	[thread overview]
Message-ID: <06240213-dbc6-ea1c-ca49-28663387ac70@linux.intel.com> (raw)
In-Reply-To: <BN9PR11MB527689614CBD807A113493B48CED9@BN9PR11MB5276.namprd11.prod.outlook.com>

On 2022/4/12 15:39, Tian, Kevin wrote:
>> From: Lu Baolu <baolu.lu@linux.intel.com>
>> Sent: Sunday, April 10, 2022 6:25 PM
>> @@ -898,6 +941,20 @@ int iommu_group_add_device(struct iommu_group
>> *group, struct device *dev)
>>   	list_add_tail(&device->list, &group->devices);
>>   	if (group->domain  && !iommu_is_attach_deferred(dev))
>>   		ret = __iommu_attach_device(group->domain, dev);
>> +
>> +	/*
>> +	 * Use standard PCI bus topology, isolation features, and DMA
>> +	 * alias quirks to set the immutable singleton attribute. If
>> +	 * the device came from DT, assume it is static and then
>> +	 * singleton can know from the device count in the group.
>> +	 */
>> +	if (dev_is_pci(dev))
>> +		group->immutable_singleton =
>> +				pci_immutably_isolated(to_pci_dev(dev));
>> +	else if (is_of_node(dev_fwnode(dev)))
>> +		group->immutable_singleton =
>> +				(iommu_group_device_count(group) == 1);
>> +
> 
> btw probably we also want to check when a 2nd device is added
> to a group marked as singleton, just in case some weird thing happens?

It depends on how we judge whether the group to which a DT device
belongs is a singleton. As I explained in another thread, current trick
doesn't support doing this.

Best regards,
baolu
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Lu Baolu <baolu.lu@linux.intel.com>
To: "Tian, Kevin" <kevin.tian@intel.com>,
	Joerg Roedel <joro@8bytes.org>, Jason Gunthorpe <jgg@nvidia.com>,
	Christoph Hellwig <hch@infradead.org>,
	"Raj, Ashok" <ashok.raj@intel.com>, Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.com>
Cc: baolu.lu@linux.intel.com, Eric Auger <eric.auger@redhat.com>,
	"Liu, Yi L" <yi.l.liu@intel.com>,
	"Pan, Jacob jun" <jacob.jun.pan@intel.com>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC v3 02/12] iommu: Add a flag to indicate immutable singleton group
Date: Tue, 12 Apr 2022 21:10:03 +0800	[thread overview]
Message-ID: <06240213-dbc6-ea1c-ca49-28663387ac70@linux.intel.com> (raw)
In-Reply-To: <BN9PR11MB527689614CBD807A113493B48CED9@BN9PR11MB5276.namprd11.prod.outlook.com>

On 2022/4/12 15:39, Tian, Kevin wrote:
>> From: Lu Baolu <baolu.lu@linux.intel.com>
>> Sent: Sunday, April 10, 2022 6:25 PM
>> @@ -898,6 +941,20 @@ int iommu_group_add_device(struct iommu_group
>> *group, struct device *dev)
>>   	list_add_tail(&device->list, &group->devices);
>>   	if (group->domain  && !iommu_is_attach_deferred(dev))
>>   		ret = __iommu_attach_device(group->domain, dev);
>> +
>> +	/*
>> +	 * Use standard PCI bus topology, isolation features, and DMA
>> +	 * alias quirks to set the immutable singleton attribute. If
>> +	 * the device came from DT, assume it is static and then
>> +	 * singleton can know from the device count in the group.
>> +	 */
>> +	if (dev_is_pci(dev))
>> +		group->immutable_singleton =
>> +				pci_immutably_isolated(to_pci_dev(dev));
>> +	else if (is_of_node(dev_fwnode(dev)))
>> +		group->immutable_singleton =
>> +				(iommu_group_device_count(group) == 1);
>> +
> 
> btw probably we also want to check when a 2nd device is added
> to a group marked as singleton, just in case some weird thing happens?

It depends on how we judge whether the group to which a DT device
belongs is a singleton. As I explained in another thread, current trick
doesn't support doing this.

Best regards,
baolu

  reply	other threads:[~2022-04-12 13:10 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-10 10:24 [PATCH RFC v3 00/12] iommu: SVA and IOPF refactoring Lu Baolu
2022-04-10 10:24 ` Lu Baolu
2022-04-10 10:24 ` [PATCH RFC v3 01/12] iommu: Add pasid_bits field in struct dev_iommu Lu Baolu
2022-04-10 10:24   ` Lu Baolu
2022-04-10 10:24 ` [PATCH RFC v3 02/12] iommu: Add a flag to indicate immutable singleton group Lu Baolu
2022-04-10 10:24   ` Lu Baolu
2022-04-12  3:15   ` Tian, Kevin
2022-04-12  3:15     ` Tian, Kevin
2022-04-12  5:08     ` Lu Baolu
2022-04-12  5:08       ` Lu Baolu
2022-04-12  6:34       ` Yi Liu
2022-04-12  6:34         ` Yi Liu
2022-04-12 11:56         ` Lu Baolu
2022-04-12 11:56           ` Lu Baolu
2022-04-12  7:37       ` Tian, Kevin
2022-04-12  7:37         ` Tian, Kevin
2022-04-12 13:02         ` Lu Baolu
2022-04-12 13:02           ` Lu Baolu
2022-04-12 23:32           ` Tian, Kevin
2022-04-12 23:32             ` Tian, Kevin
2022-04-13 12:02             ` Lu Baolu
2022-04-13 12:02               ` Lu Baolu
2022-04-12  7:39   ` Tian, Kevin
2022-04-12  7:39     ` Tian, Kevin
2022-04-12 13:10     ` Lu Baolu [this message]
2022-04-12 13:10       ` Lu Baolu
2022-04-10 10:24 ` [PATCH RFC v3 03/12] iommu: Add attach/detach_dev_pasid domain ops Lu Baolu
2022-04-10 10:24   ` Lu Baolu
2022-04-10 10:24 ` [PATCH RFC v3 04/12] iommu/sva: Basic data structures for SVA Lu Baolu
2022-04-10 10:24   ` Lu Baolu
2022-04-12  6:49   ` Tian, Kevin
2022-04-12  6:49     ` Tian, Kevin
2022-04-12 11:58     ` Lu Baolu
2022-04-12 11:58       ` Lu Baolu
2022-04-12  6:56   ` Tian, Kevin
2022-04-12  6:56     ` Tian, Kevin
2022-04-12 12:08     ` Lu Baolu
2022-04-12 12:08       ` Lu Baolu
2022-04-10 10:24 ` [PATCH RFC v3 05/12] iommu/vt-d: Remove SVM_FLAG_SUPERVISOR_MODE support Lu Baolu
2022-04-10 10:24   ` Lu Baolu
2022-04-10 10:24 ` [PATCH RFC v3 06/12] iommu/vt-d: Add SVA domain support Lu Baolu
2022-04-10 10:24   ` Lu Baolu
2022-04-10 10:24 ` [PATCH RFC v3 07/12] arm-smmu-v3/sva: " Lu Baolu
2022-04-10 10:24   ` Lu Baolu
2022-04-10 10:24 ` [PATCH RFC v3 08/12] iommu/sva: Use attach/detach_pasid_dev in SVA interfaces Lu Baolu
2022-04-10 10:24   ` Lu Baolu
2022-04-12  7:19   ` Tian, Kevin
2022-04-12  7:19     ` Tian, Kevin
2022-04-12 12:53     ` Lu Baolu
2022-04-12 12:53       ` Lu Baolu
2022-04-12 23:36       ` Tian, Kevin
2022-04-12 23:36         ` Tian, Kevin
2022-04-13 11:57         ` Lu Baolu
2022-04-13 11:57           ` Lu Baolu
2022-04-14  3:44           ` Tian, Kevin
2022-04-14  3:44             ` Tian, Kevin
2022-04-10 10:24 ` [PATCH RFC v3 09/12] iommu: Remove SVA related callbacks from iommu ops Lu Baolu
2022-04-10 10:24   ` Lu Baolu
2022-04-10 10:24 ` [PATCH RFC v3 10/12] iommu: Prepare IOMMU domain for IOPF Lu Baolu
2022-04-10 10:24   ` Lu Baolu
2022-04-10 10:24 ` [PATCH RFC v3 11/12] iommu: Per-domain I/O page fault handling Lu Baolu
2022-04-10 10:24   ` Lu Baolu
2022-04-10 10:24 ` [PATCH RFC v3 12/12] iommu: Rename iommu-sva-lib.{c,h} Lu Baolu
2022-04-10 10:24   ` Lu Baolu

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