From: Lu Baolu <baolu.lu@linux.intel.com>
To: Keqian Zhu <zhukeqian1@huawei.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
iommu@lists.linux-foundation.org,
Robin Murphy <robin.murphy@arm.com>,
Will Deacon <will@kernel.org>, Joerg Roedel <joro@8bytes.org>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
Yi Sun <yi.y.sun@linux.intel.com>,
Tian Kevin <kevin.tian@intel.com>
Cc: baolu.lu@linux.intel.com,
Alex Williamson <alex.williamson@redhat.com>,
Kirti Wankhede <kwankhede@nvidia.com>,
Cornelia Huck <cohuck@redhat.com>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>,
wanghaibin.wang@huawei.com, jiangkunkun@huawei.com,
yuzenghui@huawei.com, lushenming@huawei.com
Subject: Re: [RFC PATCH v4 01/13] iommu: Introduce dirty log tracking framework
Date: Thu, 13 May 2021 20:02:47 +0800 [thread overview]
Message-ID: <ce19e7a0-e7b7-aa09-b074-ad555d42bab2@linux.intel.com> (raw)
In-Reply-To: <bbc1960c-24f3-680a-b6ff-c81f70fa9c04@huawei.com>
On 5/13/21 6:58 PM, Keqian Zhu wrote:
>
>
> On 2021/5/12 19:36, Lu Baolu wrote:
>> Hi keqian,
>>
>> On 5/12/21 4:44 PM, Keqian Zhu wrote:
>>>
>>>
>>> On 2021/5/12 11:20, Lu Baolu wrote:
>>>> On 5/11/21 3:40 PM, Keqian Zhu wrote:
>>>>>> For upper layers, before starting page tracking, they check the
>>>>>> dirty_page_trackable attribution of the domain and start it only it's
>>>>>> capable. Once the page tracking is switched on the vendor iommu driver
>>>>>> (or iommu core) should block further device attach/detach operations
>>>>>> until page tracking is stopped.
>>>>> But when a domain becomes capable after detaching a device, the upper layer
>>>>> still needs to query it and enable dirty log for it...
>>>>>
>>>>> To make things coordinated, maybe the upper layer can register a notifier,
>>>>> when the domain's capability change, the upper layer do not need to query, instead
>>>>> they just need to realize a callback, and do their specific policy in the callback.
>>>>> What do you think?
>>>>>
>>>>
>>>> That might be an option. But why not checking domain's attribution every
>>>> time a new tracking period is about to start?
>>> Hi Baolu,
>>>
>>> I'll add an attribution in iommu_domain, and the vendor iommu driver will update
>>> the attribution when attach/detach devices.
>>>
>>> The attribute should be protected by a lock, so the upper layer shouldn't access
>>> the attribute directly. Then the iommu_domain_support_dirty_log() still should be
>>> retained. Does this design looks good to you?
>>
>> Yes, that's what I was thinking of. But I am not sure whether it worth
>> of a lock here. It seems not to be a valid behavior for upper layer to
>> attach or detach any device while doing the dirty page tracking.
> Hi Baolu,
>
> Right, if the "detach|attach" interfaces and "dirty tracking" interfaces can be called concurrently,
> a lock in iommu_domain_support_dirty_log() is still not enough. I will add another note for the dirty
> tracking interfaces.
>
> Do you have other suggestions? I will accelerate the progress, so I plan to send out v5 next week.
No further comments expect below nit:
"iommu_switch_dirty_log: Perform actions to start|stop dirty log tracking"
How about splitting it into
- iommu_start_dirty_log()
- iommu_stop_dirty_log()
Not a strong opinion anyway.
Best regards,
baolu
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next prev parent reply other threads:[~2021-05-13 12:06 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-07 10:21 [RFC PATCH v4 00/13] iommu/smmuv3: Implement hardware dirty log tracking Keqian Zhu
2021-05-07 10:21 ` [RFC PATCH v4 01/13] iommu: Introduce dirty log tracking framework Keqian Zhu
2021-05-08 3:46 ` Lu Baolu
2021-05-08 7:35 ` Keqian Zhu
2021-05-10 1:08 ` Lu Baolu
2021-05-10 11:07 ` Keqian Zhu
2021-05-11 3:12 ` Lu Baolu
2021-05-11 7:40 ` Keqian Zhu
2021-05-12 3:20 ` Lu Baolu
2021-05-12 8:44 ` Keqian Zhu
2021-05-12 11:36 ` Lu Baolu
2021-05-13 10:58 ` Keqian Zhu
2021-05-13 12:02 ` Lu Baolu [this message]
2021-05-14 2:30 ` Keqian Zhu
2021-05-07 10:22 ` [RFC PATCH v4 02/13] iommu/io-pgtable-arm: Add quirk ARM_HD and ARM_BBMLx Keqian Zhu
2021-05-07 10:22 ` [RFC PATCH v4 03/13] iommu/io-pgtable-arm: Add and realize split_block ops Keqian Zhu
2021-05-07 10:22 ` [RFC PATCH v4 04/13] iommu/io-pgtable-arm: Add and realize merge_page ops Keqian Zhu
2021-05-07 10:22 ` [RFC PATCH v4 05/13] iommu/io-pgtable-arm: Add and realize sync_dirty_log ops Keqian Zhu
2021-05-07 10:22 ` [RFC PATCH v4 06/13] iommu/io-pgtable-arm: Add and realize clear_dirty_log ops Keqian Zhu
2021-05-07 10:22 ` [RFC PATCH v4 07/13] iommu/arm-smmu-v3: Add support for Hardware Translation Table Update Keqian Zhu
2021-05-07 10:22 ` [RFC PATCH v4 08/13] iommu/arm-smmu-v3: Enable HTTU for stage1 with io-pgtable mapping Keqian Zhu
2021-05-07 10:22 ` [RFC PATCH v4 09/13] iommu/arm-smmu-v3: Add feature detection for BBML Keqian Zhu
2021-05-07 10:22 ` [RFC PATCH v4 10/13] iommu/arm-smmu-v3: Realize switch_dirty_log iommu ops Keqian Zhu
2021-05-07 10:22 ` [RFC PATCH v4 11/13] iommu/arm-smmu-v3: Realize sync_dirty_log " Keqian Zhu
2021-05-07 10:22 ` [RFC PATCH v4 12/13] iommu/arm-smmu-v3: Realize clear_dirty_log " Keqian Zhu
2021-05-07 10:22 ` [RFC PATCH v4 13/13] iommu/arm-smmu-v3: Realize support_dirty_log " Keqian Zhu
2021-05-17 8:46 ` [RFC PATCH v4 00/13] iommu/smmuv3: Implement hardware dirty log tracking Keqian Zhu
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