Re: [PATCH v4 0/5] virtio-gpu: Add userptr support for compute workloads

[Dmitry Osipenko]

On 1/15/26 10:58, Honglei Huang wrote:
> From: Honglei Huang <honghuan@xxxxxxx>
> 
> Hello,
> 
> This series adds virtio-gpu userptr support to enable ROCm native
> context for compute workloads. The userptr feature allows the host to
> directly access guest userspace memory without memcpy overhead, which is
> essential for GPU compute performance.
> 
> The userptr implementation provides buffer-based zero-copy memory access. 
> This approach pins guest userspace pages and exposes them to the host
> via scatter-gather tables, enabling efficient compute operations.
> 
> Key features:
> - Zero-copy memory access between guest userspace and host GPU
> - Read-only and read-write userptr support
> - Runtime feature detection via VIRTGPU_PARAM_RESOURCE_USERPTR
> - ROCm capset support for ROCm stack integration
> - Proper page lifecycle management with FOLL_LONGTERM pinning
> 
> Patches overview:
> 1. Add VIRTIO_GPU_CAPSET_ROCM capability for compute workloads
> 2. Add virtio-gpu API definitions for userptr blob resources
> 3. Extend DRM UAPI with comprehensive userptr support
> 4. Implement core userptr functionality with page management
> 5. Integrate userptr into blob resource creation and advertise to userspace
> 
> Performance: In popular compute benchmarks, this implementation achieves
> approximately 70% efficiency compared to bare metal OpenCL performance on
> AMD V2000 hardware, achieves 92% efficiency on AMD W7900 hardware.
> 
> Testing: Verified with ROCm stack and OpenCL applications in VIRTIO virtualized
> environments.
> - Full OPENCL CTS tests passed on ROCm 5.7.0 in V2000 platform.
> - Near 70% percentage of OPENCL CTS tests passed on ROCm 7.0 W7900 platform.
> - most HIP catch tests passed on ROCm 7.0 W7900 platform.
> - Some AI applications enabled on ROCm 7.0 W7900 platform.
> 
> V4 changes:
>     - Renamed VIRTIO_GPU_CAPSET_HSAKMT to VIRTIO_GPU_CAPSET_ROCM
>     - Remove userptr feature probing cause it can reuse the guest 
>       blob resource code path, reduce patch count from 6 to 5
>     - Updated corresponding commit messages
>     - Consolidated userptr feature detection in final patch
>     - Update corresponding cover letter content
> 
> V3 changes:
>     - Split into focused patches for easier review
>     - Removed complex interval tree userptr management 
>     - Simplified resource creation without deduplication
>     - Added VIRTGPU_PARAM_RESOURCE_USERPTR for feature detection
>     - Improved UAPI documentation and error handling
>     - Enhanced code quality with proper cleanup paths
>     - Removed MMU notifier dependencies for simplicity
>     - Fixed resource lifecycle management issues
> 
> V2: - Split add HSAKMT context and blob userptr resource to two patches.
>     - Remove MMU notifier related patches, cause use not moveable user space
>       memory with MMU notifier is not a good idea.
>     - Remove HSAKMT context check when create context, let all the context
>       support the userptr feature.
>     - Remove MMU notifier related content in cover letter.
>     - Add more comments  for patch 6 in cover letter.
> 
> Honglei Huang (5):
>   drm/virtio-gpu: Add VIRTIO_GPU_CAPSET_ROCM capability
>   virtio-gpu api: add blob userptr resource
>   drm/virtgpu api: add blob userptr resource
>   drm/virtio: implement userptr support for zero-copy memory access
>   drm/virtio: advertise base userptr feature to userspace
> 
>  drivers/gpu/drm/virtio/Makefile          |   3 +-
>  drivers/gpu/drm/virtio/virtgpu_drv.h     |  33 ++++
>  drivers/gpu/drm/virtio/virtgpu_ioctl.c   |   9 +-
>  drivers/gpu/drm/virtio/virtgpu_object.c  |   6 +
>  drivers/gpu/drm/virtio/virtgpu_userptr.c | 231 +++++++++++++++++++++++
>  include/uapi/drm/virtgpu_drm.h           |   9 +
>  include/uapi/linux/virtio_gpu.h          |   7 +
>  7 files changed, 295 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/gpu/drm/virtio/virtgpu_userptr.c
> 

Hi, could you please send rebased patches?

-- 
Best regards,
Dmitry