Commit 074fe395 authored by Donet Tom's avatar Donet Tom Committed by Alex Deucher
Browse files

drm/amdgpu: Handle GPU page faults correctly on non-4K page systems 



During a GPU page fault, the driver restores the SVM range and then maps it
into the GPU page tables. The current implementation passes a GPU-page-size
(4K-based) PFN to svm_range_restore_pages() to restore the range.

SVM ranges are tracked using system-page-size PFNs. On systems where the
system page size is larger than 4K, using GPU-page-size PFNs to restore the
range causes two problems:

Range lookup fails:
Because the restore function receives PFNs in GPU (4K) units, the SVM
range lookup does not find the existing range. This will result in a
duplicate SVM range being created.

VMA lookup failure:
The restore function also tries to locate the VMA for the faulting address.
It converts the GPU-page-size PFN into an address using the system page
size, which results in an incorrect address on non-4K page-size systems.
As a result, the VMA lookup fails with the message: "address 0xxxx VMA is
removed".

This patch passes the system-page-size PFN to svm_range_restore_pages() so
that the SVM range is restored correctly on non-4K page systems.

Acked-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarDonet Tom <donettom@linux.ibm.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 94c7e966

drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

+3 −3
Original line number Diff line number Diff line
@@ -2992,14 +2992,14 @@ bool amdgpu_vm_handle_fault(struct amdgpu_device *adev, u32 pasid, 
	if (!root)

		return false;



	addr /= AMDGPU_GPU_PAGE_SIZE;



	if (is_compute_context && !svm_range_restore_pages(adev, pasid, vmid,

	    node_id, addr, ts, write_fault)) {

	    node_id, addr >> PAGE_SHIFT, ts, write_fault)) {

		amdgpu_bo_unref(&root);

		return true;

	}



	addr /= AMDGPU_GPU_PAGE_SIZE;



	r = amdgpu_bo_reserve(root, true);

	if (r)

		goto error_unref;