Hi, Jason and Jacob,
On 3/8/23 10:23, Jason Gunthorpe wrote:
On Tue, Mar 07, 2023 at 02:32:09PM -0800, Jacob Pan wrote:
Hi Jason,
On Fri, 3 Mar 2023 09:15:45 -0400, Jason Gunthorpe <jgg@xxxxxxxxxx> wrote:
On Fri, Mar 03, 2023 at 05:57:41PM +0800, Baolu Lu wrote:
On 2023/3/3 17:32, Jean-Philippe Brucker wrote:
I suppose the common thing is reserving some kind of special
PASIDs.
Are you planning to use RID_PASID != 0 in VT-d? Otherwise we could
just communicate min_pasid from the IOMMU driver the same way we do
max_pasid.
Otherwise I guess re-introduce a lighter ioasid_alloc() that the IOMMU
driver calls to reserve PASID0/RID_PASID.
Yes. We probably will use a non-zero RID_PASID in the future. An
interface to reserve (or allocate) a PASID from iommu_global_pasid_ida
should work then.
Just allowing the driver to store XA_ZERO_ENTRY would be fine
It looks like there are incoming users of iommu_sva_find()
https://lore.kernel.org/lkml/20230306163138.587484-1-fenghua.yu@xxxxxxxxx/T/#m1fc97725a0e56ea269c8bdabacee447070d51846
Should we keep the xa here instead of the global ida?
I'm not sure this should be in the iommu core, it is really gross.
I would expect IDXD to keep track of the PASID's and mms it is using
and do this kind of stuff itself.
And why is this using access_remote_vm anyhow? If you know you are in
a kthread then kthread_use_mm() is probably better anyhow.
In any event we don't need a iommu_sva_find() function to wrapper
xa_load for another function inside the same .c file.
Ok. I will maintain mm and find mm from PASID inside IDXD driver. And
will implement accessing the remote mm inside IDXD driver although the
implementation will have duplicate code as access_remote_vm().
Thanks.
-Fenghua
