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From: Yi Liu <yi.l.liu@intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: <joro@8bytes.org>, <kevin.tian@intel.com>,
	<baolu.lu@linux.intel.com>, <alex.williamson@redhat.com>,
	<robin.murphy@arm.com>, <eric.auger@redhat.com>,
	<nicolinc@nvidia.com>, <kvm@vger.kernel.org>,
	<chao.p.peng@linux.intel.com>, <iommu@lists.linux.dev>,
	<zhenzhong.duan@intel.com>, <jacob.jun.pan@intel.com>
Subject: Re: [PATCH 1/2] iommu: Pass domain to remove_dev_pasid() op
Date: Thu, 28 Mar 2024 20:38:09 +0800	[thread overview]
Message-ID: <05d7736b-c432-4d8e-abf5-267aea036f75@intel.com> (raw)
In-Reply-To: <20240327130234.GE946323@nvidia.com>

On 2024/3/27 21:02, Jason Gunthorpe wrote:
> On Wed, Mar 27, 2024 at 05:54:32AM -0700, Yi Liu wrote:
>> Existing remove_dev_pasid() callbacks of the underlying iommu drivers get
>> the attached domain from the group->pasid_array. However, the domains
>> stored in group->pasid_array are not always correct. For example, the
>> set_dev_pasid() path updates group->pasid_array first and then invoke
>> remove_dev_pasid() callback when error happened. The remove_dev_pasid()
>> callback would get the updated domain. This is not correct for the
>> devices that are still attached with an old domain or just no attached
>> domain.
>>
>> To avoid the above problem, passing the attached domain to the
>> remove_dev_pasid() callback is more reliable.
> 
> I've relaized we have the same issue with set_dev_pasid, there is no
> way for the driver to get the old domain since the xarray was updated
> before calling set_dev_pasid. This is unlike the RID path. Meaning
> drivers can't implement PASID replace.
> 
> So we need another patch to pass the old domain into set_dev_pasid
> too...
> 
> This looks fine
> 
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

I dropped your r-b as the description changed. Please have another look
at the v2 of this patch. :)

[1] 
https://lore.kernel.org/linux-iommu/20240328122958.83332-3-yi.l.liu@intel.com/

-- 
Regards,
Yi Liu

  parent reply	other threads:[~2024-03-28 12:34 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-27 12:54 [PATCH 0/2] Two enhancements to iommu_at[de]tach_device_pasid() Yi Liu
2024-03-27 12:54 ` [PATCH 1/2] iommu: Pass domain to remove_dev_pasid() op Yi Liu
2024-03-27 13:02   ` Jason Gunthorpe
2024-03-27 13:10     ` Yi Liu
2024-03-28 12:38     ` Yi Liu [this message]
2024-03-28  3:12   ` Tian, Kevin
2024-03-28  6:28     ` Yi Liu
2024-03-27 12:54 ` [PATCH 2/2] iommu: Undo pasid attachment only for the devices that have succeeded Yi Liu
2024-03-27 13:05   ` Jason Gunthorpe
2024-03-27 13:12     ` Yi Liu
2024-03-28  3:15   ` Tian, Kevin
2024-03-28  6:29     ` Yi Liu

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