On 2026. július 2., csütörtök 12:22:23 közép-európai nyári idő Christian König
wrote:
> On 7/1/26 18:17, Timur Kristóf wrote:
> > PTE_IS_PTE seems necessary for handling retry faults on GFX12.
> >
> > For reference see:
> > amdgpu_vm_pte_update_flags() that explains the problem
> > svm_range_get_pte_flags() that uses the flag on GFX12
> >
> > Also add NOALLOC on GFX10.3+ as we don't need to allocate
> > the fault handling PTE in the infinity cache (MALL).
> >
> > Signed-off-by: Timur Kristóf <[email protected]>
> > ---
> >
> > drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 8 ++++++--
> > 1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c index 32719f31b6c9..a915d061085f
> > 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> > @@ -3044,7 +3044,8 @@ bool amdgpu_vm_handle_fault(struct amdgpu_device
> > *adev, u32 pasid,>
> > }
> >
> > addr /= AMDGPU_GPU_PAGE_SIZE;
> >
> > - flags = AMDGPU_PTE_VALID | AMDGPU_PTE_SNOOPED |
> > + flags = adev->gmc.init_pte_flags |
> > + AMDGPU_PTE_VALID | AMDGPU_PTE_SNOOPED |
> >
> > AMDGPU_PTE_SYSTEM;
>
> That doesn't make sense the PTE flags should be adjusted to the device
> specific flags by the callbacks.
Can you please elaborate on what is it that doesn't make sense here and why,
and what you recommend to do instead?
> > if (is_compute_context) {
> >
> > @@ -3054,11 +3055,14 @@ bool amdgpu_vm_handle_fault(struct amdgpu_device
> > *adev, u32 pasid,>
> > flags = AMDGPU_VM_NORETRY_FLAGS;
> > value = 0;
> >
> > } else if (amdgpu_vm_fault_stop == AMDGPU_VM_FAULT_STOP_NEVER) {
> >
> > + /* Don't allocate this PTE in the MALL */
> > + if (amdgpu_ip_version(adev, GC_HWIP, 0) >=
IP_VERSION(10, 3, 0))
> > + flags |= AMDGPU_PTE_NOALLOC;
> > +
>
> This doesn't make sense either, mall allocation for the dummy page should be
> perfectly fine.
I think we shouldn't waste space for this PTE in the MALL.
>
> > /* Redirect the access to the dummy page */
> > value = adev->dummy_page_addr;
> > flags |= AMDGPU_PTE_EXECUTABLE | AMDGPU_PTE_READABLE |
> >
> > AMDGPU_PTE_WRITEABLE;
> >
> > -
> >
> > } else {
> >
> > /* Let the hw retry silently on the PTE */
> > value = 0;
