From: Donet Tom <[email protected]> [ Upstream commit 42ea9cf2f16b7131cb7302acb3dac510968f8bdc ]
HW-supported EOP buffer sizes are 4K and 32K. On systems that do not use 4K pages, the minimum buffer object (BO) allocation size is PAGE_SIZE (for example, 64K). During queue buffer acquisition, the driver currently checks the allocated BO size against the supported EOP buffer size. Since the allocated BO is larger than the expected size, this check fails, preventing queue creation. Relax the strict size validation and allow PAGE_SIZE-sized BOs to be used. Only the required 4K region of the buffer will be used as the EOP buffer and avoids queue creation failures on non-4K page systems. Acked-by: Christian König <[email protected]> Suggested-by: Philip Yang <[email protected]> Signed-off-by: Donet Tom <[email protected]> Signed-off-by: Felix Kuehling <[email protected]> Reviewed-by: Felix Kuehling <[email protected]> Signed-off-by: Alex Deucher <[email protected]> Signed-off-by: Sasha Levin <[email protected]> --- LLM Generated explanations, may be completely bogus: The commit being analyzed fixes a bug introduced by `629568d25fea8` ("Validate queue cwsr area and eop buffer size"), which added overly strict validation. The validation was correct for 4K-page systems but broke non-4K-page systems. The current fix relaxes the validation to properly handle the page-size alignment used by the memory allocator. ### Conclusion This is a clear, small, well-reviewed bug fix that restores GPU compute functionality on non-4K page size systems. The change is logically correct (allowing larger-than-needed buffers and aligning to page size boundaries), has minimal risk, and has been thoroughly reviewed by AMD GPU subsystem maintainers. It fixes a regression introduced by a prior validation commit. The fix meets all stable kernel criteria: it's obviously correct, fixes a real and severe bug (complete loss of GPU compute on affected systems), is small in scope (4 lines, 1 file), and introduces no new features. **YES** drivers/gpu/drm/amd/amdkfd/kfd_queue.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_queue.c b/drivers/gpu/drm/amd/amdkfd/kfd_queue.c index 80c4fa2b0975d..2822c90bd7be4 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_queue.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_queue.c @@ -275,8 +275,8 @@ int kfd_queue_acquire_buffers(struct kfd_process_device *pdd, struct queue_prope /* EOP buffer is not required for all ASICs */ if (properties->eop_ring_buffer_address) { - if (properties->eop_ring_buffer_size != topo_dev->node_props.eop_buffer_size) { - pr_debug("queue eop bo size 0x%x not equal to node eop buf size 0x%x\n", + if (properties->eop_ring_buffer_size < topo_dev->node_props.eop_buffer_size) { + pr_debug("queue eop bo size 0x%x is less than node eop buf size 0x%x\n", properties->eop_ring_buffer_size, topo_dev->node_props.eop_buffer_size); err = -EINVAL; @@ -284,7 +284,7 @@ int kfd_queue_acquire_buffers(struct kfd_process_device *pdd, struct queue_prope } err = kfd_queue_buffer_get(vm, (void *)properties->eop_ring_buffer_address, &properties->eop_buf_bo, - properties->eop_ring_buffer_size); + ALIGN(properties->eop_ring_buffer_size, PAGE_SIZE)); if (err) goto out_err_unreserve; } -- 2.51.0
