[PATCH i-g-t v1 0/2] tests/amdgpu: add SVM (shared virtual memory) test suite

This series adds IGT coverage for the amdgpu SVM (shared virtual memory)
uAPI, which exposes HMM-based unified virtual memory to user space
through the amdgpu render node CS path (DRM_IOCTL_AMDGPU_GEM_SVM).
Until now, SVM has only been testable via the KFD/ROCm stack; this
brings equivalent coverage to the DRM render-node interface.

The work is split into two patches so the reusable pieces land
independently of the test:

  1. lib/amdgpu: a small helper library (lib/amdgpu/amd_svm.{c,h})
     wrapping the SVM register/prefetch ioctls and the compute/SDMA
     submission needed to touch SVM ranges, plus the amdgpu_drm.h uAPI
     sync and meson wiring.

  2. tests/amdgpu: the amd_svm test itself, with subtests covering
     system- and VRAM-backed allocation, prefetch, CPU<->GPU migration
     and access-in-place, range split/merge, partial unmap, eviction of
     system ranges, and VRAM overcommit. Most subtests are adapted from
     the KFD SVM test suite (KFDSVMRangeTest) and ported to the amdgpu
     render-node CS path.

Testing:
  Run on a VEGA20 (GFX9) dGPU against an amdgpu kernel with the SVM
  uAPI applied, with XNACK enabled. The suite passes except for two
  expected cases:
    - set-get-attributes: fails due to a known kernel-side stale 
      attribute reporting issue (kept to track the fix).
    - read-only-range: skipped, as the kernel write-fault path is not
      yet safe to exercise.

Dependency:
  This series depends on the amdgpu SVM kernel support: the new uAPI
  (DRM_IOCTL_AMDGPU_GEM_SVM) together with its amdgpu driver
  implementation built on the DRM GPUSVM framework.

  Its userspace entry point is provided by libdrm (amdgpu_svm_*
  wrappers in libdrm_amdgpu); the amd_svm helper library in patch 1
  builds on top of that, and its bundled amdgpu_drm.h mirrors the
  kernel uAPI.

  Kernel series (uAPI + amdgpu DRM SVM implementation):
    https://lore.kernel.org/all/[email protected]/
  libdrm support (userspace DRM_IOCTL_AMDGPU_GEM_SVM wrappers):
    https://gitlab.freedesktop.org/mesa/libdrm/-/merge_requests/485

Junhua Shen (2):
  lib/amdgpu: add SVM helper library and uAPI
  tests/amdgpu: add SVM test suite

 include/drm-uapi/amdgpu_drm.h |  106 ++
 lib/amdgpu/amd_svm.c          |  215 ++++
 lib/amdgpu/amd_svm.h          |   42 +
 lib/meson.build               |    1 +
 tests/amdgpu/amd_svm.c        | 2184 +++++++++++++++++++++++++++++++++
 tests/amdgpu/meson.build      |    1 +
 6 files changed, 2549 insertions(+)
 create mode 100644 lib/amdgpu/amd_svm.c
 create mode 100644 lib/amdgpu/amd_svm.h
 create mode 100644 tests/amdgpu/amd_svm.c


base-commit: 0385a3845f2b29c202df21ebe7928462c98536f5
-- 
2.34.1