On 6/23/26 10:12, Srinivasan Shanmugam wrote:
> Current VM fault handling resolves PASIDs through VM state:
>
> PASID -> VM
>
> That is sufficient for VM fault handling, but process-scoped event
> delivery paths need a different semantic mapping:
>
> PASID -> amdgpu_fpriv
>
> Although both mappings are indexed by PASID, they serve different
> purposes:
>
> vm_manager.pasids
> PASID -> VM fault handling
>
> vm_manager.pasid_fprivs
> PASID -> process-scoped DRM file-private owner
>
> Add a PASID fpriv xarray beside the existing PASID to VM xarray.
>
> Cc: Alex Deucher <[email protected]>
> Cc: Christian König <[email protected]>
> Signed-off-by: Srinivasan Shanmugam <[email protected]>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 5 +++++
> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 13 +++++++++++++
> 2 files changed, 18 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index 450bd9dc6bc0..3141ae1383b0 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -2869,6 +2869,8 @@ void amdgpu_vm_manager_init(struct amdgpu_device *adev)
> #endif
>
> xa_init_flags(&adev->vm_manager.pasids, XA_FLAGS_LOCK_IRQ);
> + xa_init_flags(&adev->vm_manager.pasid_fprivs,
> + XA_FLAGS_LOCK_IRQ);
I think we should completely remove &adev->vm_manager.pasids.
Take a look at amdgpu_pasid_alloc(), we already store the PASIDs in the global
amdgpu_pasid_xa xarray.
But instead of a real value we just give xa_mk_value(0) as dummy for the entry.
I think we can re-use that array to store pasid->fpriv mapping. It just needs
proper locking and interface to retrive the fpriv for a pasid (while holding
the XA lock irqsave).
Let me know when you have more questions.
Regards,
Christian.
> }
>
> /**
> @@ -2881,7 +2883,10 @@ void amdgpu_vm_manager_init(struct amdgpu_device *adev)
> void amdgpu_vm_manager_fini(struct amdgpu_device *adev)
> {
> WARN_ON(!xa_empty(&adev->vm_manager.pasids));
> + WARN_ON(!xa_empty(&adev->vm_manager.pasid_fprivs));
> +
> xa_destroy(&adev->vm_manager.pasids);
> + xa_destroy(&adev->vm_manager.pasid_fprivs);
>
> amdgpu_vmid_mgr_fini(adev);
> amdgpu_pasid_mgr_cleanup();
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> index 4d96bb8c2c6d..5318e833bd97 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> @@ -450,6 +450,8 @@ struct amdgpu_vm {
> struct amdgpu_vm_fault_info fault_info;
> };
>
> +struct amdgpu_fpriv;
> +
> struct amdgpu_vm_manager {
> /* Handling of VMIDs */
> struct amdgpu_vmid_mgr id_mgr[AMDGPU_MAX_VMHUBS];
> @@ -484,6 +486,17 @@ struct amdgpu_vm_manager {
> * look up VM of a page fault
> */
> struct xarray pasids;
> +
> + /*
> + * PASID to DRM file-private mapping.
> + *
> + * This is separate from @pasids. @pasids answers which VM
> + * should be used for VM fault handling, while @pasid_fprivs
> + * answers which DRM file-private owner should receive
> + * process-scoped events.
> + */
> + struct xarray pasid_fprivs;
> +
> /* Global registration of recent page fault information */
> struct amdgpu_vm_fault_info fault_info;
> };
