Messages in this thread | | | From | "Tian, Kevin" <> | Subject | RE: [PATCH 0/5] Share sva domains with all devices bound to a mm | Date | Wed, 9 Aug 2023 09:44:11 +0000 |
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> From: Baolu Lu <baolu.lu@linux.intel.com> > Sent: Wednesday, August 9, 2023 8:18 AM > > On 2023/8/8 15:49, Tina Zhang wrote: > > A sva domain's lifetime begins with binding a device to a mm and ends > > by releasing all the bound devices from that sva domain. Technically, > > there could be more than one sva domain identified by the mm PASID for > > the use of bound devices issuing DMA transactions. > > > > To support mm PASID 1:n with sva domains, each mm needs to keep both > a > > reference list of allocated sva domains and the corresponding PASID. > > However, currently, mm struct only has one pasid field for sva usage, > > which is used to keep the info of an assigned PASID. That pasid field > > cannot provide sufficient info to build up the 1:n mapping between PASID > > and sva domains. > > Is it more appropriate to have the same life cycle for sva domain and mm > pasid? I feel that they represent the same thing, that is, the address > space shared by mm to a device. >
iirc it's a simplification to free mm pasid at __mmdrop() otherwise the implementation is tricky, but I don't remember all the detail...
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