Messages in this thread | | | Subject | Re: [RFC] /dev/ioasid uAPI proposal | From | Jason Wang <> | Date | Wed, 2 Jun 2021 16:52:02 +0800 |
| |
在 2021/6/2 上午4:28, Jason Gunthorpe 写道: >> I summarized five opens here, about: >> >> 1) Finalizing the name to replace /dev/ioasid; >> 2) Whether one device is allowed to bind to multiple IOASID fd's; >> 3) Carry device information in invalidation/fault reporting uAPI; >> 4) What should/could be specified when allocating an IOASID; >> 5) The protocol between vfio group and kvm; >> >> For 1), two alternative names are mentioned: /dev/iommu and >> /dev/ioas. I don't have a strong preference and would like to hear >> votes from all stakeholders. /dev/iommu is slightly better imho for >> two reasons. First, per AMD's presentation in last KVM forum they >> implement vIOMMU in hardware thus need to support user-managed >> domains. An iommu uAPI notation might make more sense moving >> forward. Second, it makes later uAPI naming easier as 'IOASID' can >> be always put as an object, e.g. IOMMU_ALLOC_IOASID instead of >> IOASID_ALLOC_IOASID.:) > I think two years ago I suggested /dev/iommu and it didn't go very far > at the time.
It looks to me using "/dev/iommu" excludes the possibility of implementing IOASID in a device specific way (e.g through the co-operation with device MMU + platform IOMMU)?
What's more, ATS spec doesn't forbid the device #PF to be reported via a device specific way.
Thanks
> We've also talked about this as /dev/sva for a while and > now /dev/ioasid > > I think /dev/iommu is fine, and call the things inside them IOAS > objects. > > Then we don't have naming aliasing with kernel constructs. >
| |