On 2019-11-18 17:24, Alex Sierra wrote:
Only for the debugger use case.
[why]
Avoid endless translation retries, after an invalid address access has
been issued to the GPU. Instead, the trap handler is forced to enter by
generating a no-retry-fault.
A s_trap instruction is inserted in the debugger case to let the wave to
enter trap handler to save context.
[how]
Intentionally using an invalid flag combination (F and P set at the same
time) to trigger a no-retry-fault, after a retry-fault happens. This is
only valid under compute context.
Change-Id: I4180c30e2631dc0401cbd6171f8a6776e4733c9a
Signed-off-by: Alex Sierra <alex.sierra@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index d51ac8771ae0..358a4f50fcfb 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -3207,6 +3207,12 @@ bool amdgpu_vm_handle_fault(struct amdgpu_device *adev, unsigned int pasid,
value = adev->dummy_page_addr;
flags |= AMDGPU_PTE_EXECUTABLE | AMDGPU_PTE_READABLE |
AMDGPU_PTE_WRITEABLE;
+
+ if (vm->is_compute_context) {
+ /* Setting PTE flags to trigger a no-retry-fault */
+ flags = AMDGPU_PTE_EXECUTABLE | AMDGPU_PDE_PTE |
+ AMDGPU_PTE_TF;
Hmm, this looks like you're setting flags twice in the compute-case. I
was also expecting something more like this:
if (vm->is_compute_context) {
...
} else if (amdgpu_vm_fault_stop == AMDGPU_VM_FAULT_STOP_NEVER) {
...
} else {
...
}
I.e. for compute contexts, we do our compute-specific thing, otherwise
the behaviour depends on the amdgpu_vm_fault_stop setting.
Regards,
Felix
+ }
} else {
/* Let the hw retry silently on the PTE */
value = 0;
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